Research ArticleAnalysis of Hydration and Optimal Strength Combinations ofCement-Limestone-Metakaolin Ternary Composite
Xiao-Yong Wang
Department of Architectural Engineering Kangwon National University Chuncheon-Si Republic of Korea
Correspondence should be addressed to Xiao-Yong Wang wxbravekangwonackr
Received 28 January 2019 Revised 28 March 2019 Accepted 2 April 2019 Published 2 May 2019
Guest Editor Rishi Gupta
Copyright copy 2019 Xiao-YongWang +is is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited
Metakaolin (MK) is an aluminosilicate pozzolan material and can contribute to property development of concrete due to thepozzolanic reaction Limestone (LS) powder presents the dilution effect nucleation effect and chemical effect on hydration ofcement When metakaolin and limestone are used together due to the additional chemical reaction between the aluminum phasein MK and limestone the synergetic benefit can be achieved +is study presents a hydration model for cement-limestone-metakaolin ternary blends Individual reactions of cement metakaolin and limestone are simulated separately and the in-teractions among cement hydration limestone reaction and metakaolin reaction are considered through the contents of calciumhydroxide and capillary water +e hydration model considers the pozzolanic reaction of metakaolin chemical and physics effectsof limestone and synergetic effect between metakaolin and limestone Furthermore the gel-space ratio of hydrating concrete iscalculated using reaction degrees of binders and concrete mixtures+e strength development of ternary blends is evaluated usingthe gel-space ratio Based on parameter analysis the synergetic effect on strength development is shown and the optimalcombinations of cement-limestone-metakaolin ternary blends are determined
1 Introduction
Metakaolin is increasingly used in modern concrete in-dustry +e addition of metakaolin can make many ad-vantages on the performance of concrete Metakaolin canenhance workability and finishing ability increase com-pressive and flexural strength and reduce chloride perme-ability However metakaolin-blended binary concrete hassome drawbacks As the replacement level of cement bymetakaolin increases an increased amount of super-plasticizer is necessary to reach the required consistency+ematerial cost of the metakaolin is higher than that of cementTo avoid these drawbacks the substitution level of cement bymetakaolin is generally lower than 25 Summarily thebenefits of metakaolin such as mechanical performance andextended service life may overcome its negative effectMetakaolin is a very promising supplementary cementitiousmaterial for the concrete industry [1 2]
Limestone powder can improve the workability reducethe bleeding and reduce the amount of CO2 emission of theconcrete industry+e price of limestone is much lower than
that of metakaolin+e addition of limestone lowers the late-age strength of concrete When limestone and metakaolinare used together the pozzolanic reaction of metakaolin cancontribute to concrete late-age strength In addition met-akaolin has a high aluminum content which can react withlimestone form carboaluminate phases and increase solidvolume and strength of concrete +is is the synergetic effectof ternary concrete While metakaolin or limestone is addedindividually the synergetic effect cannot be achieved Insummary when using metakaolin- and limestone ternary-blended concrete the economic benefit and strength benefitcan be achieved [1 2]
Many experimental studies have been done aboutworkability mechanical and durability aspects of cement-limestone-metakaolin ternary blends Vance et al [3] re-ported that for cement-limestone-metakaolin ternaryblends the yield stress reduces as the limestone contentincreases +is is because of the particle packing waterdemand and interparticle spacing and contacts Vance et al[4] found that the synergetic effect of limestone andMK incorporation can improve early-age properties and
HindawiAdvances in Materials Science and EngineeringVolume 2019 Article ID 8361810 13 pageshttpsdoiorg10115520198361810
maintain late-age properties of concrete Alvarez et al [5]presented that combined mixtures of limestone and MKenhance compressive strength compared with 100 Port-land cement concrete Ramezanianpour and Hooton [6]presented that carboaluminate hydrates are formed forcement-limestone-MK ternary blends and there is an op-timum level of limestone in terms of the maximum strengthand minimum porosity Perlot et al [7] reported thatternary-blended mix presents a real benefit for carbonationdurability performances due to the refinement of the porestructure Sotiriadis et al [8] reported that the use of MK inthe limestone cement concrete retards and inhibits de-terioration due to the sulfate attack and improves itsdurability
Compared with abundant experimental studies thetheoretical models about cement-limestone-metakaolinternary blends are very limited Antoni et al [9] made thethermodynamic model for cement-limestone-metakaolinternary blends and present phase assemblage for differentcombinations of binders Shi et al [10 11] presented thethermodynamic model for carbonation and chloride in-gression of cement-limestone-metakaolin ternary blendsChanges in phase assemblages and total porosities due tocarbonation and chloride exposure are evaluated [10 11]+e thermodynamic models [9ndash11] mainly focus on thechemical aspect of ternary blends such as the phase as-semblages of hydrated concrete and reaction products be-tween concrete and ingression ions However limited workswas done about mechanical aspects such as the evaluation ofstrength development and optimal combinations of bindersof ternary blends [9ndash11]
Optimal combinations of binders of ternary blends arean interesting topic for concrete manufacture and con-struction company +is study presents a blended hydrationmodel for ternary blends considering the synergetic effectbetween limestone and MK +e strength development ofternary blends is evaluated using reaction degrees of bindersand gel-space ratios Based on parameter analysis the op-timal combinations of cement-limestone-metakaolin ter-nary blends are determined
2 Hydration Model and Strength Model forTernary Blends
21 Hydration Model For MK- and limestone-blendedconcrete the hydration of cement the reaction of MKand reaction of limestone coexist In this study we simulatethe hydration of cement MK and limestone respectivelyMeanwhile the interactions among cement hydrationmetakaolin reaction and limestone reaction are consideredthrough the contents of capillary water and calcium hy-droxide in hydrating blends
211 Cement Hydration Model +e hydration of cementcan be described using a kinetic model shown in our formerstudies [12] +e degree of hydration α can be calculated asα 1113938
t
0 (dαdt)dt where t is the time and dαdt is the rate ofhydration which can be determined as follows
dαdt
f(B CDe kr) lowast λ1 lowast λ2 (1)
where B and C are the rate-determining coefficients in theinitial dormant period De is the reaction parameter inthe diffusion-controlled period kr is the reaction parame-ter in the phase boundary-controlled period λ1 considersthe reduction of the hydration rate due to developmentof microstructure and λ2 considers the reduction of hy-dration rate due to the consumption of capillary water(λ2 WcapW0 where Wcap is the amount of capillary waterand W0 is the amount of water in concrete mixtures)
+e kinetic processes involved in cement hydration suchas the initial dormant process phase boundary reactionprocess and diffusion process are considered in the cementhydration model +e input variables of the cement hy-dration model are cement compound compositions Blainesurface of cement concrete mixing proportions and curingconditions+e values of hydration parameters B C De andkr can be determined using cement compound composi-tions Furthermore the reaction degree of cement can becalculated automatically using hydration parameters B CDe and kr +e effect of curing temperature on cementhydration is considered using Arrhenius law [12] For high-strength concrete the water-to-cement ratio is low and thehydration rate is significantly lowered due to the reductionof capillary water [13 14] +is effect is considered usingcapillary water concentration λ2 Summarily the proposedcement hydration model is valid for concrete with differentstrength levels different types of Portland cement anddifferent curing conditions [12]
212 MK ReactionModel +e reaction process of MK alsoconsists of the initial dormant process phase boundaryreaction process and diffusion process which is similarwith the processes involved in hydration of cement [15]On the contrary MK is a pozzolanic material +e re-action rate of the pozzolanic reaction is dependent on theamount of calcium hydroxide in blends [16 17] Con-sidering the kinetic reaction processes and the essenceof MK as the pozzolanic material Wang [15] proposedthat the reaction equation of MK can be written asfollows
dαMK
dt f BMK CMKDeMK krMK( 1113857 lowast
CH(t)
P (2)
where αMK is the reaction degree of MK dαMKdt is thereaction rate of MK BMK and CMK are reaction parametersof MK in the dormant period DeMK is the reaction pa-rameter of MK in the diffusion-controlled period krMK is thereaction parameter of MK in the phase boundary-controlledperiod CH(t) is the content of calcium hydroxide in blendsand P is the content of MK in concrete mixtures +everifications of the MK reaction model are available in ourformer study [15] An integrated hydration-strength-durability model for MK-blended concrete is proposedfor evaluating the reaction degrees of binders strengthdevelopment and chloride penetrability [15]
2 Advances in Materials Science and Engineering
213 Limestone Reaction Model +e addition of limestonepowder presents the dilution effect nucleation effect andchemical effect on hydration of cement In this study di-lution effect is considered through the amount of capillarywater nucleation effect is considered through a nucleationeffect indicator and chemical effect is considered through alogarithm function with multiple modification factors[18 19]
+e hydration products of cement can form on thesurface of limestone powder +is is called as the nucleationeffect +e nucleation effect indicator of limestone powdercan be written as follows [2]
Lr LS0 lowast SLS
C0 lowast SC (3)
where Lr is the limestone nucleation effect indicator LS0 andC0 are the mass of limestone and cement in mixing pro-portions respectively and SLS and SC are the Blaine surfacearea of limestone powder and cement respectively
In our former study [2] based on the experimentalresults of hydration degree of cement in cement-limestonebinary blends Wang and Luan [2] proposed that the nu-cleation effect of limestone powder can be described asfollows
krLS kr 1 + 12Lr( 1113857 (4)
DeLS De 1 + 12Lr( 1113857 (5)
where krLS is the updated phase boundary reaction co-efficient in cement-limestone blends 12 is enhancing co-efficients of kr [2] DeLS is the updated diffusion coefficient incement-limestone blends and 12 is enhancing coefficientsof De [2]
Until now the experimental results about the reactiondegree of limestone are very limit Tentatively Wang andLuan [2] proposed an empirical model with multi-modification factors for analyzing the reaction degree oflimestone +e empirical model considers the effects ofvarious factors on the chemical reaction of limestone suchas limestone replacement ratios mineral admixtures addi-tions limestone fineness cement fineness water-to-binderratio and curing temperature +e empirical model for thelimestone reaction is shown as follows
αLS1 00087 ln(t)minus 00265 tgt 21 hours (6)
αLS αLS1 lowast m1 lowast m2 lowast m3 lowast m4 lowast m5 lowast m6 (7)
where αLS1 is the reaction degree of limestone in a referencemixture +is reference mixture is Portland cement andlimestone binary blends with a water-to-binder ratio 05 and20 limestone addition cured at 20degC m1 considers the effectof limestone replacement ratios on the reaction degree oflimestone m2 considers the effect of limestone fineness m3considers the effect of cement finenessm4 considers the effectofMK additionm5 considers the effect of the water-to-binderratio and m6 considers the effect of the curing temperatureTable 1 shows the summary of influencing factors of thelimestone reaction As limestone replacement ratio increases
reaction degree of LS decreases While fineness of limestonefineness of cement MK addition and water to binder ratioincrease the reaction degree of LS increases Especially formodification factor m4 1 + (AlMKαMKPAlCαC0) whereAlMK is the aluminum content in MK AlC is the aluminumcontent in cement AlMKαMKP in the numerator is reactedaluminum content from the MK reaction and AlCαC0 indenominator is the reacted aluminum content from the ce-ment reaction Because the aluminum content in MK is muchhigher than that in cement the addition of MK can signifi-cantly improve the reactivity of limestone +e factor m4considers the synergetic effect of limestone and MK A higheraluminum content and a higher reactivity of MK are effectiveto enhance the reactivity of limestone
Summarily this study considers the dilution effectnucleation effect and chemical effect of limestone addi-tions +e enhancement of limestone reactivity due to theaddition of metakaolin is considered through a modifi-cation factor +e influences of other factors such aslimestone replacement ratio fineness of binders andwater-to-binder ratios are also considered in the limestonereaction model
214 Interaction Model among Cement Metakaolin andLimestone In this study the interactions among cementhydration metakaolin reaction and limestone reaction areconsidered through the contents of capillary water andcalcium hydroxide Maekawa et al [13] proposed that as 1 gcement hydrates 04 g capillary water will be consumedDunster et al [20] proposed that as 1 g metakaolin reacts055 g capillary water will be consumed Bentz [21] proposedthat as 1 g limestone reacts 162 g capillary water will beconsumed For hydrating cement-metakaolin-limestoneternary blends the content of capillary water can be de-termined as follows
Wcap W0 minus 04lowastC0 lowast αminus 055 lowast αMK lowast P
minus 162 lowast LS0 lowast αLS(8)
where 04 lowast C0 lowast α 055 lowast αMK lowast P and 162 lowast LS0 lowast αLSare the contents of consumed water from cement hydrationmetakaolin reaction and limestone reaction respectively[13 20 21] +e consumption of capillary water from the 1 glimestone reaction is much higher than those of cement andmetakaolin +is is because the reaction products of lime-stone powder are monocarboaluminate and ettringite whichcontains abundant water
For hydrating cement-metakaolin-limestone ternaryblends the content of calcium hydroxide can be determinedas follows
CH(t) RCHCE lowast C0 lowast αminus vMK lowast αMK lowastP (9)
where RCHCE means the mass of CH produced from thehydration of 1 unit mass of cement and vMK means the massof CH consumed from the reaction of 1 unit mass ofmetakaolin [15] RCHCE lowast C0 lowast α is the mass of CH pro-duced from cement hydration vMK lowast αMK lowast P is the massof CH consumed from the metakaolin reaction
Advances in Materials Science and Engineering 3
Summarily the effect of cement hydration metakaolinreaction and limestone reaction on the contents of capillarywater and calcium hydroxide is considered +e capillarywater content can be used for the cement hydration model(equation (1)) and the calcium hydroxide content can beused for the metakaolin reaction model (equation (2)) Inaddition because the blended hydration model has con-sidered the interactions among cement metakaolin andlimestone reactions the coefficients of the hydration modeldo not vary with different mixtures When the mixtureschange from one to another the coefficients of the hydrationmodel are constant
22 Strength Development Model +e gel-space ratio de-notes the ratio of the volume of binder hydration products tothe sum of volume of hydrated binders and capillary poreFor cement-metakaolin-limestone blends 1ml hydratedcement 1ml reacted metakaolin and 1ml reacted limestoneoccupy 206ml of space [16 22] 252ml space [16 22] and41ml space respectively Reacted products of 1ml lime-stone can occupy much higher space that those of cement(41 vs 206)+is is due to the development of ettringite andmonocarboaluminate from the limestone reaction Con-sidering the reactions of cement metakaolin and limestonethe gel-space ratio of cement-metakaolin-limestone ternary-blended cement can be determined as follows
xc 206 1ρC( 1113857αC0 + 252 1ρMK( 1113857αMKP + 41 1ρLS( 1113857αLSLS0
1ρC( 1113857αC0 + 1ρMK( 1113857αMKP + 1ρLS( 1113857αLSLS0 + W0
(10)
where ρC ρMK and ρLS are densities of cement metakaolinand limestone powder respectively
According to Powersrsquo strength theory the compressivestrength of hydrating concrete can be evaluated using thegel-space ratio as follows
fc(t) Axnc (11)
where fc(t) is the concrete compressive strength A is theintrinsic strength of concrete and n is the strength exponent
For cement-metakaolin-limestone blends cementmetakaolin and limestone will affect the intrinsic strength ofconcrete and strength exponent We assume that the in-trinsic strength of concrete A and strength exponent n is
proportional to the weight fractions of cement metakaolinand limestone in the mixing proportion as follows
A a1 lowastC0
C0 + P + LS0+ a2 lowast
P
C0 + P + LS0
+ a3 lowastLS0
C0 + P + LS0
(12)
n b1 lowastC0
C0 + P + LS0+ b2 lowast
P
C0 + P + LS0
+ b3 lowastLS0
C0 + P + LS0
(13)
where coefficients a1 a2 and a3 in equation (12) representthe contributions of cement metakaolin and limestone tothe intrinsic strength of concrete respectively and the unitsof a1 a2 and a3 are MPa the coefficients b1 b2 and b3 inequation (13) represent the contributions of cement met-akaolin and limestone to the strength exponent re-spectively For neat Portland cement concrete withoutlimestone or metakaolin the strength of concrete onlypertains to a1 and b1 For metakaolin-blended binaryconcrete without limestone the strength of concrete pertainsto coefficients a1 a2 b1 and b2 For ternary-blendedconcrete the strength of concrete pertains to coefficientsa1 a2 a3 b1 b2 and b3+ese coefficients a1 a2 a3 b1 b2and b3 do not change for various mixing proportions ofconcrete
+e flowchart of calculation is proven in Figure 1 Eachtime step the response levels of cement metakaolin andlimestone powder are calculated by utilizing ternary-blendedhydration model +e quantity of CH and capillary water arebased on using reaction levels of binders and concretemixtures In addition the gel-space ratio of hydratingconcrete is decided thinking about the contributions fromreactions of cement metakaolin and limestone reactions Byutilizing Powersrsquo strength theory the compressive strengthof hardening concrete is calculated
3 Verifications of Proposed Models
31 Verification of Hydration Model Experimental resultsfrom Antoni et al [9] are used to verify the proposedblended hydration model and strength development model
Table 1 Summary of influencing factors of the limestone reaction
Factor Equation Influencing trend
Limestone replacement ratios m1 02(LS0(C0 + LS0))As the limestone replacement ratio increases αLS
decreases
Fineness of limestone m2 10131minus 00144 lowast dLS where dLS is an averagediameter of limestone As fineness of limestone increases αLS increases
Fineness of cement m3 055(SCSC1) + 045 where SC1 is the Blainesurface of cement used in the reference study As fineness of cement increases αLS increases
Metakaolin additions m4 1 + (AlMKαMKPAlCαC0) As the MK addition increases αLS increases
Water-to-binder ratios m5 αα05 where α05 is the reaction degreeof cement in the reference study As water-to-binder ratio increases αLS increases
Curing temperature m6 1 Curing temperature does not present significantinfluence on αLS
4 Advances in Materials Science and Engineering
Antoni et al [9] measured the reaction degrees of binder andcompressive strength of cement-MK-LS ternary-blendedconcrete +e chemical compositions of cement meta-kaolin and limestone are shown in Table 2 +e mixingproportions are shown in Table 3 Paste specimens with awater-to-binder ratio of 04 were used for measuring re-action degree of binders Mortar specimens with a water-to-binder ratio of 05 were used for measuring compressivestrength For cement-limestone binary blends the re-placement ratio of limestone was 15 while for cement-metakaolin binary blends the replacement ratio of meta-kaolin was 30 For ternary-blended specimens the sum oflimestone and metakaolin ranged from 15 to 60 and themass ratio of metakaolin to limestone was fixed as 2 +ereaction degrees and strength were measured at the ages of 17 28 and 90 days
+e input parameters of the ternary-blended cementhydration model are concrete mixtures curing temperatureand compound compositions and Blaine surface areas ofbinders By using the blended cement hydration model thereaction degree of MK and LS is calculated and shown inFigure 2
As shown in Figure 2(a) the sequences of the reactiondegree of MK from higher to lower are B15gtB30gtMK30gtB45gtB60 +is can be explained using the MK reactionmodel (equation (2)) As shown in equation (2) the reactiondegree of MKmainly depends on the mass ratio of cement to
MK As the ratio of cement to MK increases the activationeffect from cement hydration is enhanced and reactiondegree of MK increases +e mass ratios of cement to MKwere 85 35 233 183 and 1 in the mixtures of B15 B30MK30 B45 and B60 respectively +e orders of reactiondegree of MK are consistent with the mass ratios of cementto MK
As shown in Figure 2(b) the sequences of reactiondegree of limestone from higher to lower areB15 gt B30 gt B45 gt B60 +e proposed ternary-blendedhydration model can reflect this trend of reaction de-gree of LS In this study the mass ratio of MK to LS internary blends is constant and the difference of the re-action degree of LS is mainly due to the variations of thecement-to-limestone ratio +e mass ratios of cement toLS were 17 7 366 and 2 in the mixtures of B15 B30 B45and B60 respectively As the mass ratio of cement to LSdecreases the reaction degree of LS also decreases (pa-rameter m1 of equation (7)) +e trend of the reactiondegree of LS is consistent with the mass ratio of cement toLS In addition the reaction degree of LS at 1 day is almostzero +is also agrees with our analysis As shown inequation (6) we assumed that the reaction of LS startsafter 21 hours Furthermore the reactivity of LS is verylow At the age of 90 days the reaction degree of LS for B15is 12 which is much lower than cement
Figure 3 shows the parameter analysis of the hydrationmodel Figure 3(a) shows the reaction degree of LS incement-LS binary blends As limestone replacement ratioincreases the reaction degree of limestone decreases Similarto the contents shown in Figure 3(a) Aqel and Panesar [23]
Table 2 Chemical compositions of binders
Cement()
Limestone()
Metakaolin()
SiO2 2101 004 5062Al2O3 463 006 4691Fe2O3 260 005 038CaO 6418 5653 002MgO 182 010 009SO3 278 - 008Na2O 020 004 028K2O 094 004 018TiO2 014 003 129Others 044 002 016Loss on ignition(LOI) 126 4309 000
Total 1000 1000 1000
Table 3 Mixing proportions of specimens [9]
Cement () Limestone () Metakaolin ()PC 100 0 0LS15 85 15 0MK30 70 0 30B15 85 5 10B30 70 10 20B45 55 15 30B60 40 20 40
Setting of initial conditions and calculating time tend
t = t + Δt
t gt tendNo
End
Hydration model
Calculating a degree of hydration
Δα = fce(T t) ΔαMK = fMK(T t) ΔαLS = fLS(T t)
α = α + Δα αMK = αMK + ΔαMK αLS = αLS + ΔαLS
Amount of calcium hydroxideCH(t) = RCHCE lowast C0 lowast α ndash vMK lowast αMK lowast P
Amount of capillary water
Compressive strength
Wcap = W0 ndash 04 lowast C0 lowast α ndash 055 lowast αMK lowast P ndash 162 lowast LS0 lowast αLS
fc(t) = Axcn
Figure 1 Flowchart of simulation
Advances in Materials Science and Engineering 5
also found the reactivity of limestone will be lower with theincreasing of limestone content
Figure 3(b) shows the reaction degree of MK in cement-MK binary blends As MK replacement ratio increases theactivation effect from cement hydration becomes weakerand the reaction degree of MK decreases Similar to thecontents shown in Figure 3(b) Poon et al [24] also foundsimilar results that the reaction degree ofMKwill be lower asthe content of MK increases
Figure 3(c) shows the effect of MK additions on thereaction degree of LS +e addition of MK presents thetwofold effect on reaction of LS First when MK is added toreplace partial cement in the mixtures the mass ratio ofcement to LS decreases which will lower the reaction degreeof LS (this is considered through parameter m1 of equation(7)) However the aluminum content in MK (46) is aboutten times of the aluminum content in cement (46) +eaddition of MK will enhance the reaction of LS (this isconsidered through parameter m4 of equation (7)) Becausethe enhancing effect is much more significant than thelowering effect the addition of MK can increase the reactiondegree of limestone (shown in Figure 3(c)) Similar to thecontents shown in Figure 3(c) many researchers [4 9] alsoexperimentally found that reactivity of limestone can beimproved due to MK addition
Figure 3(d) shows the effect of metakaolin and limestonecontents on the reaction degree of cement When meta-kaolin and limestone are used to replace partial cement thereaction degree of cement is improved due to the dilutioneffect and nucleation effect (the dilution effect is consideredthrough parameter λ2 in equation (1) and the nucleationeffect is considered through equations (4) and (5)) Similarto the contents shown in Figure 3(d) Lam et al [25] alsofound that the addition of mineral admixtures can improvethe reaction degree of cement
32VerificationofStrengthDevelopmentModel By using thecement-MK-LS ternary-blended hydration model the gel-space ratio of hydrating concrete can be calculated (equation(10)) Furthermore based on the strength of concrete atdifferent ages the values of strength coefficients of a1 a2and a3 and b1 b2 and b3 can be calibrated (a1 140MPaa2 258MPa a3120MPa b1 385 b2113 andb3134) +ese coefficients do not vary with concretemixtures+e values of a1 and b1 relate to cement hydrationthe values of a2 and b2 relate to the metakaolin reaction andthe values of a3 and b3 relate to the limestone reaction Forcement-metakaolin binary blends the development ofstrength relates to a1 a2 b1 and b2 For cement-limestonebinary blends the development of strength relates to a1 a3b1 and b3 For cement-metakaolin-limestone ternaryblends the development of strength relates to a1 a2 a3 b1b2 and b3 +e analyzed results of compressive strength areshown in Figure 4 +e analysis results generally agree withexperimental results At the ages of 28 days the B15 concrete(cement 85+metakaolin 10+ limestone 5) has ahighest strength than other mixtures +is may be because ofthe synergetic effect of metakaolin and limestone
Because the strength coefficients of strength evaluationequation are constants for different concrete mixtures wecan make parameter analysis for different concrete mixturesFigure 5(a) shows the strength development of cement-limestone binary blends At the early age due to the nu-cleation effect the strength of limestone blends concreteshows higher strength than control concrete While at lateages due to the dilution effect the strength of limestoneblends concrete is lower than control concrete As thecontents of limestone increases from 10 to 20 the late-age strength decreases +e trend shown in Figure 5(a)agrees with Bonavetti et alrsquos [19] studies about strengthdevelopment of limestone-blended concrete
Time (hours)
08
06
04
02
0
Reac
tion
degr
ee o
f MK
100 102
MK30B15-MK10LS5B30-MK20LS10B45-MK30LS15B60-MK40LS20
Exper-MK30Exper-B15Exper-B30Exper-B45Exper-B60
(a)
100 102
Time (hours)
0
005
01
015
02
025
03
Reac
tion
degr
ee o
f lim
esto
ne p
owde
r
B15-MK10LS5B30-MK20LS10B45-MK30LS15B60-MK40LS20
Exper-B15Exper-B30Exper-B45Exper-B60
(b)
Figure 2 Verification of the hydration model (a) reaction degree of MK (b) reaction degree of LS
6 Advances in Materials Science and Engineering
Figure 5(b) shows the strength development of cement-metakaolin binary blends Metakaolin-blended concrete hasa higher strength than control concrete As the contents ofmetakaolin increases from 5 to 10 the strength alsoincreases +e trend shown in Figure 5(b) agrees with Poonet alrsquos [24] studies about strength development ofmetakaolin-blended concrete
Damidot et al [26] studies the strength development of70 cement + 30 clay-limestone ternary blends +e sumof clay and limestone was fixed as 30 and the weightfraction of clay(clay + limestone) ranges from 0 to 100[26] Damidot et al [26] found that at the age of 28 days themix with 70metakaolin has the highest strength than othermixes +is is because of the synergetic effect of limestoneand metakaolin [26] Based on the proposed strength de-velopment in this study we make parameter analysis of
strength development for 70 cement + 30 clay-limestoneternary blends In our analysis the sum of clay and limestoneis also fixed as 30 the weight fractions of clay(clay + limestone) are given as 0 25 50 75 and 100and the ages of parameter analysis are 15 days 3 days28 days and 90 days respectively +e results of parameteranalysis are shown in Figures 6(a)ndash6(d) As shown inFigure 6(a) at the age of 15 days the strength of blendedconcrete is higher than base Portland cement+is is becauseof the nucleation effect of limestone While as shown inFigures 6(b)ndash6(d) at the age of 3 days 28 days and 90 dayswhen the mk(mk + limestone) equals to zero (the content ofmetakaolin is zero and binder consists of 30 limestone and70 cement) the strength of limestone-blended concreteis lower than base Portland cement +is is because ofthe dilution effect of limestone While for other mk
0 500 1000 1500 2000 2500Time (hours)
0
001
002
003
004
005
006
007Re
actio
n de
gree
of l
imes
tone
Cement 95 + limestone 5Cement 90 + limestone 10Cement 85 + limestone 15
(a)
0 500 1000 1500 2000 2500Time (hours)
0
02
04
06
08
Reac
tion
degr
ee o
f MK
Cement 95 + MK5Cement 90 + MK10Cement 80 + MK20
(b)
0 500 1000 1500 2000 2500Time (hours)
0
001
002
003
004
005
006
007
Reac
tion
degr
ee o
f lim
esto
ne
Cement 55 + MK30 + LS15Cement 85 + MK0 + LS15
(c)
0 500 1000 1500 2000 2500Time (hours)
0
02
04
06
08
1Re
actio
n de
gree
of c
emen
t
ControlB60-MK40LS20
(d)
Figure 3 Parameter analysis of reaction degree of binders (a) effect of limestone contents on the reaction degree of limestone (b) effect ofmetakaolin contents on the reaction degree of metakaolin (c) effect of metakaolin contents on the reaction degree of limestone (d) effect ofmetakaolin and limestone contents on the reaction degree of cement
Advances in Materials Science and Engineering 7
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70C
ompr
essiv
e stre
ngth
(MPa
)
Analysis resultsExperimental results
Control
(a)
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
Analysis resultsExperimental results
(b)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
(c)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70C
ompr
essiv
e stre
ngth
(MPa
)MK 10 limestone 5
(d)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 20 limestone 10
(e)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 30 limestone 20
(f )
Figure 4 Continued
8 Advances in Materials Science and Engineering
(mk+ limestone) ratios of 25 50 75 and 100 be-cause the reaction of metakaolin can contribute to thestrength the strength of blended concrete is higher than basePortland cement
At the age of 15 days 3 days 28 days and 90 days theoptimum weight fractions of clay(clay + limestone) are 2550 75 and 75 respectively (shown in Figures 6(e)) Ouranalysis result about optimum weight fraction of clay(clay + limestone) is similar to that of Damidot et al [26]studies In addition our analysis shows that at the ages of15 days 3 days 28 days and 90 days the optimum weightfraction of limestone(clay + limestone) is 75 50 25 and25 respectively It means that at the early age limestone iseffective to improve the strength of concrete (this is because of
the nucleation effect of limestone) and at the late agemetakaolin is effective to improve the strength of concrete(this is because of the pozzolanic reaction of metakaolin)
In Figure 6 the sum of metakaolin and limestone isfixed as 30 To find the optimum combinations of ce-ment metakaolin and limestone we make much widerparameter analysis In this wider parameter analysis thesum of metakaolin and limestone is not a fixed value +econtents of metakaolin vary from 0 to 30 and thecontents of limestone vary from 0 to 20 +e analysisresults of isoline of strength are shown in Figures 7(a)ndash7(d) At the early age 15 days the concrete with a higherlimestone content and a lower metakaolin content hashighest strength (shown in Figure 7(a)) while at the late
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 40 limestone 20
(g)
Figure 4 Analysis of compressive strength (a) PC (b) LS15 (c) MK30 (d) B15 (e) B30 (f ) B45 (g) B60
10ndash2 100 102 104
Time (hours)
0
10
20
30
40
50
60
Com
pres
sive s
treng
th (M
Pa)
ControlLS10LS20
(a)
ControlMK5MK10
10ndash2 100 102 104
Time (hours)
0
20
40
60
80
Com
pres
sive s
treng
th (M
Pa)
(b)
Figure 5 Effect of LS and MK on strength development (a) cement-LS binary blends (b) cement-MK binary blends
Advances in Materials Science and Engineering 9
0 02 04 06 08 1MK(MK + limestone) weight fraction
19
195
20
205
21
215
221
5-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
Metakaolin + limestoneBase Portland cement
(a)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
25
26
27
28
29
30
3-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(b)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
35
40
45
50
55
60
28-d
ay co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(c)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
45
50
55
60
65
7090
-day
com
pres
sive s
treng
th (M
Pa)
70 PC + 30 (MK-limestone mix)
(d)
0 20 40 60 80 100Time (days)
02
03
04
05
06
07
08
Opt
imum
wei
ght f
ract
ion
in M
K +
limes
tone
ble
nds
70 PC + 30 (MK-limestone mix)
MK
(e)
Figure 6 Synergetic effect of cement-MK-LS ternary blends (MK+LS 30) (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimumfractions of MK
10 Advances in Materials Science and Engineering
age of 90 days the concrete with a higher metakaolincontent and a lower limestone content has higheststrength (shown in Figure 7(d)) In other words toachieve the highest strength of cement-metakaolin-limestone ternary blends the optimum combination ofmetakaolin and limestone is dependent on ages From theearly age to late age the optimum combinations change
shift from high limestone-low metakaolin zone to lowlimestone-high metakaolin zone (shown in Figure 7(e))
4 Conclusions
+is study presents an integrated hydration-strength modelfor cement-limestone-metakaolin ternary blends
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03M
K w
eigh
t fra
ctio
n in
tota
l bin
der
195
20
205
21
215
(a)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
265
27
275
28
285
29
295
(b)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
44
46
48
50
52
54
56
(c)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
52
54
56
58
60
62
64
66
68
(d)
008 01 012 014 016 018MK weight fraction in total binder
0
005
01
015
02
Lim
esto
ne w
eigh
t fra
ctio
n in
tota
l bin
der
15 days
3 days
28 days and90 days
(e)
Figure 7 Analysis of optimum MK and LS combinations (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimum MK and LScombinations at different ages
Advances in Materials Science and Engineering 11
First a cement hydration model a metakaolin reactionmodel and a limestone reaction model are proposed in theternary-blended hydration model Pozzolanic reaction ofmetakaolin chemical and physics effect of limestone andsynergetic effect between metakaolin and limestone aredetailed considered in the ternary-blended hydration modelMoreover the interactions among cement hydrationlimestone reaction and metakaolin reaction are consideredthrough the contents of calcium hydroxide and capillarywater+e coefficients of the hydration model do not changefor various concrete mixtures
Second based on the hydration model the gel-spaceratio of hydrating blends is calculated considering thecontributions from the reactions of cement metakaolin andlimestone Furthermore the strength development of ter-nary blends is evaluated using the gel-space ratio +e co-efficients of the strength model do not change for variousconcrete mixtures Based on parameter analysis the syn-ergetic effect on strength development is shown and theoptimal combinations of cement-limestone-metakaolinternary blends are determined From the early age to lateage the optimum combinations of ternary blends shift fromhigh limestone-low metakaolin zone to low limestone-highmetakaolin zone
Data Availability
+e data used to support the findings of this study are in-cluded within the article
Conflicts of Interest
+e author declares that there are no conflicts of interestregarding the publication of this paper
Acknowledgments
+is research was supported by Basic Science ResearchProgram through the National Research Foundation ofKorea (NRF) funded by the Ministry of Science ICT andFuture Planning (no 2015R1A5A1037548) and a NRF grant(NRF-2017R1C1B1010076)
References
[1] X-Y Wang ldquoModeling of hydration compressive strengthand carbonation of Portland-limestone cement (PLC) con-creterdquo Materials vol 10 no 2 pp 115ndash131 2017
[2] X Y Wang and Y Luan ldquoModeling of hydration strengthdevelopment and optimum combinations of cement-slag-limestone ternary concreterdquo International Journal of Con-crete Structures and Materials vol 12 no 1 pp 193ndash2062018
[3] K Vance A Kumar G Sant and N Neithalath ldquo+e rhe-ological properties of ternary binders containing Portlandcement limestone and metakaolin or fly ashrdquo Cement andConcrete Research vol 52 pp 196ndash207 2013
[4] K Vance M Aguayo T Oey G Sant and N NeithalathldquoHydration and strength development in ternary portlandcement blends containing limestone and fly ash or
metakaolinrdquo Cement and Concrete Composites vol 39pp 93ndash103 2013
[5] G L Alvarez A Nazari A Bagheri J G Sanjayan andC De Lange ldquoMicrostructure electrical and mechanicalproperties of steel fibres reinforced cement mortars withpartial metakaolin and limestone additionrdquo Construction andBuilding Materials vol 135 pp 8ndash20 2017
[6] A M Ramezanianpour and R D Hooton ldquoA study on hy-dration compressive strength and porosity of Portland-limestone cement mixes containing SCMsrdquo Cement andConcrete Composites vol 51 pp 1ndash13 2014
[7] C Perlot P Rougeau and S Dehaudt ldquoSlurry of metakaolincombined with limestone addition for self-compacted con-crete application for precast industryrdquo Cement and ConcreteComposites vol 44 pp 50ndash57 2013
[8] K Sotiriadis E Nikolopoulou S Tsivilis A PavlouE Chaniotakis and R N Swamy ldquo+e effect of chlorides onthe thaumasite form of sulfate attack of limestone cementconcrete containing mineral admixtures at low temperaturerdquoConstruction and Building Materials vol 43 pp 156ndash1642013
[9] M Antoni J Rossen F Martirena and K Scrivener ldquoCementsubstitution by a combination of metakaolin and limestonerdquoCement and Concrete Research vol 42 no 12 pp 1579ndash15892012
[10] Z Shi M R Geiker K De Weerdt et al ldquoRole of calcium onchloride binding in hydrated Portland cement-metakaolin-limestone blendsrdquo Cement and Concrete Research vol 95pp 205ndash216 2017
[11] Z Shi B Lothenbach M R Geiker et al ldquoExperimentalstudies and thermodynamic modeling of the carbonation ofPortland cement metakaolin and limestonemortarsrdquo Cementand Concrete Research vol 88 pp 60ndash72 2016
[12] X-Y Wang and H-S Lee ldquoModeling the hydration ofconcrete incorporating fly ash or slagrdquo Cement and ConcreteResearch vol 40 no 7 pp 984ndash996 2010
[13] K Maekawa R Chaube and T Kishi Modelling of ConcretePerformance Hydration Microstructure and Mass TransportCRC Press London UK 1999
[14] K van Breugel Simulation of Hydration and Formation ofStructure in Hardening Cement-Based Materials Delft Uni-versity Press Delft Netherlands 1997
[15] X-Y Wang ldquoAnalysis of hydration-mechanical-durabilityproperties of metakaolin blended concreterdquo Applied Sci-ences vol 7 no 10 pp 1087ndash1102 2017
[16] V G Papadakis ldquoExperimental investigation and theoreticalmodeling of silica fume activity in concreterdquo Cement andConcrete Research vol 29 no 1 pp 79ndash86 1999
[17] Y Elakneswaran E Owaki S Miyahara M OginoT Maruya and T Nawa ldquoHydration study of slag-blendedcement based on thermodynamic considerationsrdquo Con-struction and Building Materials vol 124 pp 615ndash625 2016
[18] T Vuk V Tinta R Gabrovsek and V Kaucic ldquo+e effects oflimestone addition clinker type and fineness on properties ofPortland cementrdquo Cement and Concrete Research vol 31no 1 pp 135ndash139 2001
[19] V Bonavetti H Donza G Menendez O Cabrera andE F Irassar ldquoLimestone filler cement in low wc concrete arational use of energyrdquo Cement and Concrete Researchvol 33 no 6 pp 865ndash871 2003
[20] A M Dunster J R Parsonage and M J K +omas ldquo+epozzolanic reaction of metakaolinite and its effects onPortland cement hydrationrdquo Journal of Materials Sciencevol 28 no 5 pp 1345ndash1350 1993
12 Advances in Materials Science and Engineering
[21] D P Bentz ldquoModeling the influence of limestone filler oncement hydration using CEMHYD3Drdquo Cement and ConcreteComposites vol 28 no 2 pp 124ndash129 2006
[22] B Pichler C Hellmich J Eberhardsteiner et al ldquoEffect of gel-space ratio and microstructure on strength of hydrating ce-mentitious materials an engineering micromechanics ap-proachrdquo Cement and Concrete Research vol 45 pp 55ndash682013
[23] M Aqel and D K Panesar ldquoHydration kinetics and com-pressive strength of steam-cured cement pastes and mortarscontaining limestone fillerrdquo Construction and Building Ma-terials vol 113 pp 359ndash368 2016
[24] C-S Poon L Lam S C Kou Y-L Wong and R WongldquoRate of pozzolanic reaction of metakaolin in high-performance cement pastesrdquo Cement and Concrete Re-search vol 31 no 9 pp 1301ndash1306 2001
[25] L Lam Y L Wong and C S Poon ldquoDegree of hydration andgelspace ratio of high-volume fly ashcement systemsrdquo Ce-ment and Concrete Research vol 30 no 5 pp 747ndash756 2000
[26] D Damidot B Lothenbach D Herfort and F P Glasserldquo+ermodynamics and cement sciencerdquo Cement and ConcreteResearch vol 41 no 7 pp 679ndash695 2011
Advances in Materials Science and Engineering 13
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Submit your manuscripts atwwwhindawicom
maintain late-age properties of concrete Alvarez et al [5]presented that combined mixtures of limestone and MKenhance compressive strength compared with 100 Port-land cement concrete Ramezanianpour and Hooton [6]presented that carboaluminate hydrates are formed forcement-limestone-MK ternary blends and there is an op-timum level of limestone in terms of the maximum strengthand minimum porosity Perlot et al [7] reported thatternary-blended mix presents a real benefit for carbonationdurability performances due to the refinement of the porestructure Sotiriadis et al [8] reported that the use of MK inthe limestone cement concrete retards and inhibits de-terioration due to the sulfate attack and improves itsdurability
Compared with abundant experimental studies thetheoretical models about cement-limestone-metakaolinternary blends are very limited Antoni et al [9] made thethermodynamic model for cement-limestone-metakaolinternary blends and present phase assemblage for differentcombinations of binders Shi et al [10 11] presented thethermodynamic model for carbonation and chloride in-gression of cement-limestone-metakaolin ternary blendsChanges in phase assemblages and total porosities due tocarbonation and chloride exposure are evaluated [10 11]+e thermodynamic models [9ndash11] mainly focus on thechemical aspect of ternary blends such as the phase as-semblages of hydrated concrete and reaction products be-tween concrete and ingression ions However limited workswas done about mechanical aspects such as the evaluation ofstrength development and optimal combinations of bindersof ternary blends [9ndash11]
Optimal combinations of binders of ternary blends arean interesting topic for concrete manufacture and con-struction company +is study presents a blended hydrationmodel for ternary blends considering the synergetic effectbetween limestone and MK +e strength development ofternary blends is evaluated using reaction degrees of bindersand gel-space ratios Based on parameter analysis the op-timal combinations of cement-limestone-metakaolin ter-nary blends are determined
2 Hydration Model and Strength Model forTernary Blends
21 Hydration Model For MK- and limestone-blendedconcrete the hydration of cement the reaction of MKand reaction of limestone coexist In this study we simulatethe hydration of cement MK and limestone respectivelyMeanwhile the interactions among cement hydrationmetakaolin reaction and limestone reaction are consideredthrough the contents of capillary water and calcium hy-droxide in hydrating blends
211 Cement Hydration Model +e hydration of cementcan be described using a kinetic model shown in our formerstudies [12] +e degree of hydration α can be calculated asα 1113938
t
0 (dαdt)dt where t is the time and dαdt is the rate ofhydration which can be determined as follows
dαdt
f(B CDe kr) lowast λ1 lowast λ2 (1)
where B and C are the rate-determining coefficients in theinitial dormant period De is the reaction parameter inthe diffusion-controlled period kr is the reaction parame-ter in the phase boundary-controlled period λ1 considersthe reduction of the hydration rate due to developmentof microstructure and λ2 considers the reduction of hy-dration rate due to the consumption of capillary water(λ2 WcapW0 where Wcap is the amount of capillary waterand W0 is the amount of water in concrete mixtures)
+e kinetic processes involved in cement hydration suchas the initial dormant process phase boundary reactionprocess and diffusion process are considered in the cementhydration model +e input variables of the cement hy-dration model are cement compound compositions Blainesurface of cement concrete mixing proportions and curingconditions+e values of hydration parameters B C De andkr can be determined using cement compound composi-tions Furthermore the reaction degree of cement can becalculated automatically using hydration parameters B CDe and kr +e effect of curing temperature on cementhydration is considered using Arrhenius law [12] For high-strength concrete the water-to-cement ratio is low and thehydration rate is significantly lowered due to the reductionof capillary water [13 14] +is effect is considered usingcapillary water concentration λ2 Summarily the proposedcement hydration model is valid for concrete with differentstrength levels different types of Portland cement anddifferent curing conditions [12]
212 MK ReactionModel +e reaction process of MK alsoconsists of the initial dormant process phase boundaryreaction process and diffusion process which is similarwith the processes involved in hydration of cement [15]On the contrary MK is a pozzolanic material +e re-action rate of the pozzolanic reaction is dependent on theamount of calcium hydroxide in blends [16 17] Con-sidering the kinetic reaction processes and the essenceof MK as the pozzolanic material Wang [15] proposedthat the reaction equation of MK can be written asfollows
dαMK
dt f BMK CMKDeMK krMK( 1113857 lowast
CH(t)
P (2)
where αMK is the reaction degree of MK dαMKdt is thereaction rate of MK BMK and CMK are reaction parametersof MK in the dormant period DeMK is the reaction pa-rameter of MK in the diffusion-controlled period krMK is thereaction parameter of MK in the phase boundary-controlledperiod CH(t) is the content of calcium hydroxide in blendsand P is the content of MK in concrete mixtures +everifications of the MK reaction model are available in ourformer study [15] An integrated hydration-strength-durability model for MK-blended concrete is proposedfor evaluating the reaction degrees of binders strengthdevelopment and chloride penetrability [15]
2 Advances in Materials Science and Engineering
213 Limestone Reaction Model +e addition of limestonepowder presents the dilution effect nucleation effect andchemical effect on hydration of cement In this study di-lution effect is considered through the amount of capillarywater nucleation effect is considered through a nucleationeffect indicator and chemical effect is considered through alogarithm function with multiple modification factors[18 19]
+e hydration products of cement can form on thesurface of limestone powder +is is called as the nucleationeffect +e nucleation effect indicator of limestone powdercan be written as follows [2]
Lr LS0 lowast SLS
C0 lowast SC (3)
where Lr is the limestone nucleation effect indicator LS0 andC0 are the mass of limestone and cement in mixing pro-portions respectively and SLS and SC are the Blaine surfacearea of limestone powder and cement respectively
In our former study [2] based on the experimentalresults of hydration degree of cement in cement-limestonebinary blends Wang and Luan [2] proposed that the nu-cleation effect of limestone powder can be described asfollows
krLS kr 1 + 12Lr( 1113857 (4)
DeLS De 1 + 12Lr( 1113857 (5)
where krLS is the updated phase boundary reaction co-efficient in cement-limestone blends 12 is enhancing co-efficients of kr [2] DeLS is the updated diffusion coefficient incement-limestone blends and 12 is enhancing coefficientsof De [2]
Until now the experimental results about the reactiondegree of limestone are very limit Tentatively Wang andLuan [2] proposed an empirical model with multi-modification factors for analyzing the reaction degree oflimestone +e empirical model considers the effects ofvarious factors on the chemical reaction of limestone suchas limestone replacement ratios mineral admixtures addi-tions limestone fineness cement fineness water-to-binderratio and curing temperature +e empirical model for thelimestone reaction is shown as follows
αLS1 00087 ln(t)minus 00265 tgt 21 hours (6)
αLS αLS1 lowast m1 lowast m2 lowast m3 lowast m4 lowast m5 lowast m6 (7)
where αLS1 is the reaction degree of limestone in a referencemixture +is reference mixture is Portland cement andlimestone binary blends with a water-to-binder ratio 05 and20 limestone addition cured at 20degC m1 considers the effectof limestone replacement ratios on the reaction degree oflimestone m2 considers the effect of limestone fineness m3considers the effect of cement finenessm4 considers the effectofMK additionm5 considers the effect of the water-to-binderratio and m6 considers the effect of the curing temperatureTable 1 shows the summary of influencing factors of thelimestone reaction As limestone replacement ratio increases
reaction degree of LS decreases While fineness of limestonefineness of cement MK addition and water to binder ratioincrease the reaction degree of LS increases Especially formodification factor m4 1 + (AlMKαMKPAlCαC0) whereAlMK is the aluminum content in MK AlC is the aluminumcontent in cement AlMKαMKP in the numerator is reactedaluminum content from the MK reaction and AlCαC0 indenominator is the reacted aluminum content from the ce-ment reaction Because the aluminum content in MK is muchhigher than that in cement the addition of MK can signifi-cantly improve the reactivity of limestone +e factor m4considers the synergetic effect of limestone and MK A higheraluminum content and a higher reactivity of MK are effectiveto enhance the reactivity of limestone
Summarily this study considers the dilution effectnucleation effect and chemical effect of limestone addi-tions +e enhancement of limestone reactivity due to theaddition of metakaolin is considered through a modifi-cation factor +e influences of other factors such aslimestone replacement ratio fineness of binders andwater-to-binder ratios are also considered in the limestonereaction model
214 Interaction Model among Cement Metakaolin andLimestone In this study the interactions among cementhydration metakaolin reaction and limestone reaction areconsidered through the contents of capillary water andcalcium hydroxide Maekawa et al [13] proposed that as 1 gcement hydrates 04 g capillary water will be consumedDunster et al [20] proposed that as 1 g metakaolin reacts055 g capillary water will be consumed Bentz [21] proposedthat as 1 g limestone reacts 162 g capillary water will beconsumed For hydrating cement-metakaolin-limestoneternary blends the content of capillary water can be de-termined as follows
Wcap W0 minus 04lowastC0 lowast αminus 055 lowast αMK lowast P
minus 162 lowast LS0 lowast αLS(8)
where 04 lowast C0 lowast α 055 lowast αMK lowast P and 162 lowast LS0 lowast αLSare the contents of consumed water from cement hydrationmetakaolin reaction and limestone reaction respectively[13 20 21] +e consumption of capillary water from the 1 glimestone reaction is much higher than those of cement andmetakaolin +is is because the reaction products of lime-stone powder are monocarboaluminate and ettringite whichcontains abundant water
For hydrating cement-metakaolin-limestone ternaryblends the content of calcium hydroxide can be determinedas follows
CH(t) RCHCE lowast C0 lowast αminus vMK lowast αMK lowastP (9)
where RCHCE means the mass of CH produced from thehydration of 1 unit mass of cement and vMK means the massof CH consumed from the reaction of 1 unit mass ofmetakaolin [15] RCHCE lowast C0 lowast α is the mass of CH pro-duced from cement hydration vMK lowast αMK lowast P is the massof CH consumed from the metakaolin reaction
Advances in Materials Science and Engineering 3
Summarily the effect of cement hydration metakaolinreaction and limestone reaction on the contents of capillarywater and calcium hydroxide is considered +e capillarywater content can be used for the cement hydration model(equation (1)) and the calcium hydroxide content can beused for the metakaolin reaction model (equation (2)) Inaddition because the blended hydration model has con-sidered the interactions among cement metakaolin andlimestone reactions the coefficients of the hydration modeldo not vary with different mixtures When the mixtureschange from one to another the coefficients of the hydrationmodel are constant
22 Strength Development Model +e gel-space ratio de-notes the ratio of the volume of binder hydration products tothe sum of volume of hydrated binders and capillary poreFor cement-metakaolin-limestone blends 1ml hydratedcement 1ml reacted metakaolin and 1ml reacted limestoneoccupy 206ml of space [16 22] 252ml space [16 22] and41ml space respectively Reacted products of 1ml lime-stone can occupy much higher space that those of cement(41 vs 206)+is is due to the development of ettringite andmonocarboaluminate from the limestone reaction Con-sidering the reactions of cement metakaolin and limestonethe gel-space ratio of cement-metakaolin-limestone ternary-blended cement can be determined as follows
xc 206 1ρC( 1113857αC0 + 252 1ρMK( 1113857αMKP + 41 1ρLS( 1113857αLSLS0
1ρC( 1113857αC0 + 1ρMK( 1113857αMKP + 1ρLS( 1113857αLSLS0 + W0
(10)
where ρC ρMK and ρLS are densities of cement metakaolinand limestone powder respectively
According to Powersrsquo strength theory the compressivestrength of hydrating concrete can be evaluated using thegel-space ratio as follows
fc(t) Axnc (11)
where fc(t) is the concrete compressive strength A is theintrinsic strength of concrete and n is the strength exponent
For cement-metakaolin-limestone blends cementmetakaolin and limestone will affect the intrinsic strength ofconcrete and strength exponent We assume that the in-trinsic strength of concrete A and strength exponent n is
proportional to the weight fractions of cement metakaolinand limestone in the mixing proportion as follows
A a1 lowastC0
C0 + P + LS0+ a2 lowast
P
C0 + P + LS0
+ a3 lowastLS0
C0 + P + LS0
(12)
n b1 lowastC0
C0 + P + LS0+ b2 lowast
P
C0 + P + LS0
+ b3 lowastLS0
C0 + P + LS0
(13)
where coefficients a1 a2 and a3 in equation (12) representthe contributions of cement metakaolin and limestone tothe intrinsic strength of concrete respectively and the unitsof a1 a2 and a3 are MPa the coefficients b1 b2 and b3 inequation (13) represent the contributions of cement met-akaolin and limestone to the strength exponent re-spectively For neat Portland cement concrete withoutlimestone or metakaolin the strength of concrete onlypertains to a1 and b1 For metakaolin-blended binaryconcrete without limestone the strength of concrete pertainsto coefficients a1 a2 b1 and b2 For ternary-blendedconcrete the strength of concrete pertains to coefficientsa1 a2 a3 b1 b2 and b3+ese coefficients a1 a2 a3 b1 b2and b3 do not change for various mixing proportions ofconcrete
+e flowchart of calculation is proven in Figure 1 Eachtime step the response levels of cement metakaolin andlimestone powder are calculated by utilizing ternary-blendedhydration model +e quantity of CH and capillary water arebased on using reaction levels of binders and concretemixtures In addition the gel-space ratio of hydratingconcrete is decided thinking about the contributions fromreactions of cement metakaolin and limestone reactions Byutilizing Powersrsquo strength theory the compressive strengthof hardening concrete is calculated
3 Verifications of Proposed Models
31 Verification of Hydration Model Experimental resultsfrom Antoni et al [9] are used to verify the proposedblended hydration model and strength development model
Table 1 Summary of influencing factors of the limestone reaction
Factor Equation Influencing trend
Limestone replacement ratios m1 02(LS0(C0 + LS0))As the limestone replacement ratio increases αLS
decreases
Fineness of limestone m2 10131minus 00144 lowast dLS where dLS is an averagediameter of limestone As fineness of limestone increases αLS increases
Fineness of cement m3 055(SCSC1) + 045 where SC1 is the Blainesurface of cement used in the reference study As fineness of cement increases αLS increases
Metakaolin additions m4 1 + (AlMKαMKPAlCαC0) As the MK addition increases αLS increases
Water-to-binder ratios m5 αα05 where α05 is the reaction degreeof cement in the reference study As water-to-binder ratio increases αLS increases
Curing temperature m6 1 Curing temperature does not present significantinfluence on αLS
4 Advances in Materials Science and Engineering
Antoni et al [9] measured the reaction degrees of binder andcompressive strength of cement-MK-LS ternary-blendedconcrete +e chemical compositions of cement meta-kaolin and limestone are shown in Table 2 +e mixingproportions are shown in Table 3 Paste specimens with awater-to-binder ratio of 04 were used for measuring re-action degree of binders Mortar specimens with a water-to-binder ratio of 05 were used for measuring compressivestrength For cement-limestone binary blends the re-placement ratio of limestone was 15 while for cement-metakaolin binary blends the replacement ratio of meta-kaolin was 30 For ternary-blended specimens the sum oflimestone and metakaolin ranged from 15 to 60 and themass ratio of metakaolin to limestone was fixed as 2 +ereaction degrees and strength were measured at the ages of 17 28 and 90 days
+e input parameters of the ternary-blended cementhydration model are concrete mixtures curing temperatureand compound compositions and Blaine surface areas ofbinders By using the blended cement hydration model thereaction degree of MK and LS is calculated and shown inFigure 2
As shown in Figure 2(a) the sequences of the reactiondegree of MK from higher to lower are B15gtB30gtMK30gtB45gtB60 +is can be explained using the MK reactionmodel (equation (2)) As shown in equation (2) the reactiondegree of MKmainly depends on the mass ratio of cement to
MK As the ratio of cement to MK increases the activationeffect from cement hydration is enhanced and reactiondegree of MK increases +e mass ratios of cement to MKwere 85 35 233 183 and 1 in the mixtures of B15 B30MK30 B45 and B60 respectively +e orders of reactiondegree of MK are consistent with the mass ratios of cementto MK
As shown in Figure 2(b) the sequences of reactiondegree of limestone from higher to lower areB15 gt B30 gt B45 gt B60 +e proposed ternary-blendedhydration model can reflect this trend of reaction de-gree of LS In this study the mass ratio of MK to LS internary blends is constant and the difference of the re-action degree of LS is mainly due to the variations of thecement-to-limestone ratio +e mass ratios of cement toLS were 17 7 366 and 2 in the mixtures of B15 B30 B45and B60 respectively As the mass ratio of cement to LSdecreases the reaction degree of LS also decreases (pa-rameter m1 of equation (7)) +e trend of the reactiondegree of LS is consistent with the mass ratio of cement toLS In addition the reaction degree of LS at 1 day is almostzero +is also agrees with our analysis As shown inequation (6) we assumed that the reaction of LS startsafter 21 hours Furthermore the reactivity of LS is verylow At the age of 90 days the reaction degree of LS for B15is 12 which is much lower than cement
Figure 3 shows the parameter analysis of the hydrationmodel Figure 3(a) shows the reaction degree of LS incement-LS binary blends As limestone replacement ratioincreases the reaction degree of limestone decreases Similarto the contents shown in Figure 3(a) Aqel and Panesar [23]
Table 2 Chemical compositions of binders
Cement()
Limestone()
Metakaolin()
SiO2 2101 004 5062Al2O3 463 006 4691Fe2O3 260 005 038CaO 6418 5653 002MgO 182 010 009SO3 278 - 008Na2O 020 004 028K2O 094 004 018TiO2 014 003 129Others 044 002 016Loss on ignition(LOI) 126 4309 000
Total 1000 1000 1000
Table 3 Mixing proportions of specimens [9]
Cement () Limestone () Metakaolin ()PC 100 0 0LS15 85 15 0MK30 70 0 30B15 85 5 10B30 70 10 20B45 55 15 30B60 40 20 40
Setting of initial conditions and calculating time tend
t = t + Δt
t gt tendNo
End
Hydration model
Calculating a degree of hydration
Δα = fce(T t) ΔαMK = fMK(T t) ΔαLS = fLS(T t)
α = α + Δα αMK = αMK + ΔαMK αLS = αLS + ΔαLS
Amount of calcium hydroxideCH(t) = RCHCE lowast C0 lowast α ndash vMK lowast αMK lowast P
Amount of capillary water
Compressive strength
Wcap = W0 ndash 04 lowast C0 lowast α ndash 055 lowast αMK lowast P ndash 162 lowast LS0 lowast αLS
fc(t) = Axcn
Figure 1 Flowchart of simulation
Advances in Materials Science and Engineering 5
also found the reactivity of limestone will be lower with theincreasing of limestone content
Figure 3(b) shows the reaction degree of MK in cement-MK binary blends As MK replacement ratio increases theactivation effect from cement hydration becomes weakerand the reaction degree of MK decreases Similar to thecontents shown in Figure 3(b) Poon et al [24] also foundsimilar results that the reaction degree ofMKwill be lower asthe content of MK increases
Figure 3(c) shows the effect of MK additions on thereaction degree of LS +e addition of MK presents thetwofold effect on reaction of LS First when MK is added toreplace partial cement in the mixtures the mass ratio ofcement to LS decreases which will lower the reaction degreeof LS (this is considered through parameter m1 of equation(7)) However the aluminum content in MK (46) is aboutten times of the aluminum content in cement (46) +eaddition of MK will enhance the reaction of LS (this isconsidered through parameter m4 of equation (7)) Becausethe enhancing effect is much more significant than thelowering effect the addition of MK can increase the reactiondegree of limestone (shown in Figure 3(c)) Similar to thecontents shown in Figure 3(c) many researchers [4 9] alsoexperimentally found that reactivity of limestone can beimproved due to MK addition
Figure 3(d) shows the effect of metakaolin and limestonecontents on the reaction degree of cement When meta-kaolin and limestone are used to replace partial cement thereaction degree of cement is improved due to the dilutioneffect and nucleation effect (the dilution effect is consideredthrough parameter λ2 in equation (1) and the nucleationeffect is considered through equations (4) and (5)) Similarto the contents shown in Figure 3(d) Lam et al [25] alsofound that the addition of mineral admixtures can improvethe reaction degree of cement
32VerificationofStrengthDevelopmentModel By using thecement-MK-LS ternary-blended hydration model the gel-space ratio of hydrating concrete can be calculated (equation(10)) Furthermore based on the strength of concrete atdifferent ages the values of strength coefficients of a1 a2and a3 and b1 b2 and b3 can be calibrated (a1 140MPaa2 258MPa a3120MPa b1 385 b2113 andb3134) +ese coefficients do not vary with concretemixtures+e values of a1 and b1 relate to cement hydrationthe values of a2 and b2 relate to the metakaolin reaction andthe values of a3 and b3 relate to the limestone reaction Forcement-metakaolin binary blends the development ofstrength relates to a1 a2 b1 and b2 For cement-limestonebinary blends the development of strength relates to a1 a3b1 and b3 For cement-metakaolin-limestone ternaryblends the development of strength relates to a1 a2 a3 b1b2 and b3 +e analyzed results of compressive strength areshown in Figure 4 +e analysis results generally agree withexperimental results At the ages of 28 days the B15 concrete(cement 85+metakaolin 10+ limestone 5) has ahighest strength than other mixtures +is may be because ofthe synergetic effect of metakaolin and limestone
Because the strength coefficients of strength evaluationequation are constants for different concrete mixtures wecan make parameter analysis for different concrete mixturesFigure 5(a) shows the strength development of cement-limestone binary blends At the early age due to the nu-cleation effect the strength of limestone blends concreteshows higher strength than control concrete While at lateages due to the dilution effect the strength of limestoneblends concrete is lower than control concrete As thecontents of limestone increases from 10 to 20 the late-age strength decreases +e trend shown in Figure 5(a)agrees with Bonavetti et alrsquos [19] studies about strengthdevelopment of limestone-blended concrete
Time (hours)
08
06
04
02
0
Reac
tion
degr
ee o
f MK
100 102
MK30B15-MK10LS5B30-MK20LS10B45-MK30LS15B60-MK40LS20
Exper-MK30Exper-B15Exper-B30Exper-B45Exper-B60
(a)
100 102
Time (hours)
0
005
01
015
02
025
03
Reac
tion
degr
ee o
f lim
esto
ne p
owde
r
B15-MK10LS5B30-MK20LS10B45-MK30LS15B60-MK40LS20
Exper-B15Exper-B30Exper-B45Exper-B60
(b)
Figure 2 Verification of the hydration model (a) reaction degree of MK (b) reaction degree of LS
6 Advances in Materials Science and Engineering
Figure 5(b) shows the strength development of cement-metakaolin binary blends Metakaolin-blended concrete hasa higher strength than control concrete As the contents ofmetakaolin increases from 5 to 10 the strength alsoincreases +e trend shown in Figure 5(b) agrees with Poonet alrsquos [24] studies about strength development ofmetakaolin-blended concrete
Damidot et al [26] studies the strength development of70 cement + 30 clay-limestone ternary blends +e sumof clay and limestone was fixed as 30 and the weightfraction of clay(clay + limestone) ranges from 0 to 100[26] Damidot et al [26] found that at the age of 28 days themix with 70metakaolin has the highest strength than othermixes +is is because of the synergetic effect of limestoneand metakaolin [26] Based on the proposed strength de-velopment in this study we make parameter analysis of
strength development for 70 cement + 30 clay-limestoneternary blends In our analysis the sum of clay and limestoneis also fixed as 30 the weight fractions of clay(clay + limestone) are given as 0 25 50 75 and 100and the ages of parameter analysis are 15 days 3 days28 days and 90 days respectively +e results of parameteranalysis are shown in Figures 6(a)ndash6(d) As shown inFigure 6(a) at the age of 15 days the strength of blendedconcrete is higher than base Portland cement+is is becauseof the nucleation effect of limestone While as shown inFigures 6(b)ndash6(d) at the age of 3 days 28 days and 90 dayswhen the mk(mk + limestone) equals to zero (the content ofmetakaolin is zero and binder consists of 30 limestone and70 cement) the strength of limestone-blended concreteis lower than base Portland cement +is is because ofthe dilution effect of limestone While for other mk
0 500 1000 1500 2000 2500Time (hours)
0
001
002
003
004
005
006
007Re
actio
n de
gree
of l
imes
tone
Cement 95 + limestone 5Cement 90 + limestone 10Cement 85 + limestone 15
(a)
0 500 1000 1500 2000 2500Time (hours)
0
02
04
06
08
Reac
tion
degr
ee o
f MK
Cement 95 + MK5Cement 90 + MK10Cement 80 + MK20
(b)
0 500 1000 1500 2000 2500Time (hours)
0
001
002
003
004
005
006
007
Reac
tion
degr
ee o
f lim
esto
ne
Cement 55 + MK30 + LS15Cement 85 + MK0 + LS15
(c)
0 500 1000 1500 2000 2500Time (hours)
0
02
04
06
08
1Re
actio
n de
gree
of c
emen
t
ControlB60-MK40LS20
(d)
Figure 3 Parameter analysis of reaction degree of binders (a) effect of limestone contents on the reaction degree of limestone (b) effect ofmetakaolin contents on the reaction degree of metakaolin (c) effect of metakaolin contents on the reaction degree of limestone (d) effect ofmetakaolin and limestone contents on the reaction degree of cement
Advances in Materials Science and Engineering 7
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70C
ompr
essiv
e stre
ngth
(MPa
)
Analysis resultsExperimental results
Control
(a)
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
Analysis resultsExperimental results
(b)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
(c)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70C
ompr
essiv
e stre
ngth
(MPa
)MK 10 limestone 5
(d)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 20 limestone 10
(e)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 30 limestone 20
(f )
Figure 4 Continued
8 Advances in Materials Science and Engineering
(mk+ limestone) ratios of 25 50 75 and 100 be-cause the reaction of metakaolin can contribute to thestrength the strength of blended concrete is higher than basePortland cement
At the age of 15 days 3 days 28 days and 90 days theoptimum weight fractions of clay(clay + limestone) are 2550 75 and 75 respectively (shown in Figures 6(e)) Ouranalysis result about optimum weight fraction of clay(clay + limestone) is similar to that of Damidot et al [26]studies In addition our analysis shows that at the ages of15 days 3 days 28 days and 90 days the optimum weightfraction of limestone(clay + limestone) is 75 50 25 and25 respectively It means that at the early age limestone iseffective to improve the strength of concrete (this is because of
the nucleation effect of limestone) and at the late agemetakaolin is effective to improve the strength of concrete(this is because of the pozzolanic reaction of metakaolin)
In Figure 6 the sum of metakaolin and limestone isfixed as 30 To find the optimum combinations of ce-ment metakaolin and limestone we make much widerparameter analysis In this wider parameter analysis thesum of metakaolin and limestone is not a fixed value +econtents of metakaolin vary from 0 to 30 and thecontents of limestone vary from 0 to 20 +e analysisresults of isoline of strength are shown in Figures 7(a)ndash7(d) At the early age 15 days the concrete with a higherlimestone content and a lower metakaolin content hashighest strength (shown in Figure 7(a)) while at the late
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 40 limestone 20
(g)
Figure 4 Analysis of compressive strength (a) PC (b) LS15 (c) MK30 (d) B15 (e) B30 (f ) B45 (g) B60
10ndash2 100 102 104
Time (hours)
0
10
20
30
40
50
60
Com
pres
sive s
treng
th (M
Pa)
ControlLS10LS20
(a)
ControlMK5MK10
10ndash2 100 102 104
Time (hours)
0
20
40
60
80
Com
pres
sive s
treng
th (M
Pa)
(b)
Figure 5 Effect of LS and MK on strength development (a) cement-LS binary blends (b) cement-MK binary blends
Advances in Materials Science and Engineering 9
0 02 04 06 08 1MK(MK + limestone) weight fraction
19
195
20
205
21
215
221
5-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
Metakaolin + limestoneBase Portland cement
(a)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
25
26
27
28
29
30
3-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(b)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
35
40
45
50
55
60
28-d
ay co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(c)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
45
50
55
60
65
7090
-day
com
pres
sive s
treng
th (M
Pa)
70 PC + 30 (MK-limestone mix)
(d)
0 20 40 60 80 100Time (days)
02
03
04
05
06
07
08
Opt
imum
wei
ght f
ract
ion
in M
K +
limes
tone
ble
nds
70 PC + 30 (MK-limestone mix)
MK
(e)
Figure 6 Synergetic effect of cement-MK-LS ternary blends (MK+LS 30) (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimumfractions of MK
10 Advances in Materials Science and Engineering
age of 90 days the concrete with a higher metakaolincontent and a lower limestone content has higheststrength (shown in Figure 7(d)) In other words toachieve the highest strength of cement-metakaolin-limestone ternary blends the optimum combination ofmetakaolin and limestone is dependent on ages From theearly age to late age the optimum combinations change
shift from high limestone-low metakaolin zone to lowlimestone-high metakaolin zone (shown in Figure 7(e))
4 Conclusions
+is study presents an integrated hydration-strength modelfor cement-limestone-metakaolin ternary blends
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03M
K w
eigh
t fra
ctio
n in
tota
l bin
der
195
20
205
21
215
(a)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
265
27
275
28
285
29
295
(b)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
44
46
48
50
52
54
56
(c)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
52
54
56
58
60
62
64
66
68
(d)
008 01 012 014 016 018MK weight fraction in total binder
0
005
01
015
02
Lim
esto
ne w
eigh
t fra
ctio
n in
tota
l bin
der
15 days
3 days
28 days and90 days
(e)
Figure 7 Analysis of optimum MK and LS combinations (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimum MK and LScombinations at different ages
Advances in Materials Science and Engineering 11
First a cement hydration model a metakaolin reactionmodel and a limestone reaction model are proposed in theternary-blended hydration model Pozzolanic reaction ofmetakaolin chemical and physics effect of limestone andsynergetic effect between metakaolin and limestone aredetailed considered in the ternary-blended hydration modelMoreover the interactions among cement hydrationlimestone reaction and metakaolin reaction are consideredthrough the contents of calcium hydroxide and capillarywater+e coefficients of the hydration model do not changefor various concrete mixtures
Second based on the hydration model the gel-spaceratio of hydrating blends is calculated considering thecontributions from the reactions of cement metakaolin andlimestone Furthermore the strength development of ter-nary blends is evaluated using the gel-space ratio +e co-efficients of the strength model do not change for variousconcrete mixtures Based on parameter analysis the syn-ergetic effect on strength development is shown and theoptimal combinations of cement-limestone-metakaolinternary blends are determined From the early age to lateage the optimum combinations of ternary blends shift fromhigh limestone-low metakaolin zone to low limestone-highmetakaolin zone
Data Availability
+e data used to support the findings of this study are in-cluded within the article
Conflicts of Interest
+e author declares that there are no conflicts of interestregarding the publication of this paper
Acknowledgments
+is research was supported by Basic Science ResearchProgram through the National Research Foundation ofKorea (NRF) funded by the Ministry of Science ICT andFuture Planning (no 2015R1A5A1037548) and a NRF grant(NRF-2017R1C1B1010076)
References
[1] X-Y Wang ldquoModeling of hydration compressive strengthand carbonation of Portland-limestone cement (PLC) con-creterdquo Materials vol 10 no 2 pp 115ndash131 2017
[2] X Y Wang and Y Luan ldquoModeling of hydration strengthdevelopment and optimum combinations of cement-slag-limestone ternary concreterdquo International Journal of Con-crete Structures and Materials vol 12 no 1 pp 193ndash2062018
[3] K Vance A Kumar G Sant and N Neithalath ldquo+e rhe-ological properties of ternary binders containing Portlandcement limestone and metakaolin or fly ashrdquo Cement andConcrete Research vol 52 pp 196ndash207 2013
[4] K Vance M Aguayo T Oey G Sant and N NeithalathldquoHydration and strength development in ternary portlandcement blends containing limestone and fly ash or
metakaolinrdquo Cement and Concrete Composites vol 39pp 93ndash103 2013
[5] G L Alvarez A Nazari A Bagheri J G Sanjayan andC De Lange ldquoMicrostructure electrical and mechanicalproperties of steel fibres reinforced cement mortars withpartial metakaolin and limestone additionrdquo Construction andBuilding Materials vol 135 pp 8ndash20 2017
[6] A M Ramezanianpour and R D Hooton ldquoA study on hy-dration compressive strength and porosity of Portland-limestone cement mixes containing SCMsrdquo Cement andConcrete Composites vol 51 pp 1ndash13 2014
[7] C Perlot P Rougeau and S Dehaudt ldquoSlurry of metakaolincombined with limestone addition for self-compacted con-crete application for precast industryrdquo Cement and ConcreteComposites vol 44 pp 50ndash57 2013
[8] K Sotiriadis E Nikolopoulou S Tsivilis A PavlouE Chaniotakis and R N Swamy ldquo+e effect of chlorides onthe thaumasite form of sulfate attack of limestone cementconcrete containing mineral admixtures at low temperaturerdquoConstruction and Building Materials vol 43 pp 156ndash1642013
[9] M Antoni J Rossen F Martirena and K Scrivener ldquoCementsubstitution by a combination of metakaolin and limestonerdquoCement and Concrete Research vol 42 no 12 pp 1579ndash15892012
[10] Z Shi M R Geiker K De Weerdt et al ldquoRole of calcium onchloride binding in hydrated Portland cement-metakaolin-limestone blendsrdquo Cement and Concrete Research vol 95pp 205ndash216 2017
[11] Z Shi B Lothenbach M R Geiker et al ldquoExperimentalstudies and thermodynamic modeling of the carbonation ofPortland cement metakaolin and limestonemortarsrdquo Cementand Concrete Research vol 88 pp 60ndash72 2016
[12] X-Y Wang and H-S Lee ldquoModeling the hydration ofconcrete incorporating fly ash or slagrdquo Cement and ConcreteResearch vol 40 no 7 pp 984ndash996 2010
[13] K Maekawa R Chaube and T Kishi Modelling of ConcretePerformance Hydration Microstructure and Mass TransportCRC Press London UK 1999
[14] K van Breugel Simulation of Hydration and Formation ofStructure in Hardening Cement-Based Materials Delft Uni-versity Press Delft Netherlands 1997
[15] X-Y Wang ldquoAnalysis of hydration-mechanical-durabilityproperties of metakaolin blended concreterdquo Applied Sci-ences vol 7 no 10 pp 1087ndash1102 2017
[16] V G Papadakis ldquoExperimental investigation and theoreticalmodeling of silica fume activity in concreterdquo Cement andConcrete Research vol 29 no 1 pp 79ndash86 1999
[17] Y Elakneswaran E Owaki S Miyahara M OginoT Maruya and T Nawa ldquoHydration study of slag-blendedcement based on thermodynamic considerationsrdquo Con-struction and Building Materials vol 124 pp 615ndash625 2016
[18] T Vuk V Tinta R Gabrovsek and V Kaucic ldquo+e effects oflimestone addition clinker type and fineness on properties ofPortland cementrdquo Cement and Concrete Research vol 31no 1 pp 135ndash139 2001
[19] V Bonavetti H Donza G Menendez O Cabrera andE F Irassar ldquoLimestone filler cement in low wc concrete arational use of energyrdquo Cement and Concrete Researchvol 33 no 6 pp 865ndash871 2003
[20] A M Dunster J R Parsonage and M J K +omas ldquo+epozzolanic reaction of metakaolinite and its effects onPortland cement hydrationrdquo Journal of Materials Sciencevol 28 no 5 pp 1345ndash1350 1993
12 Advances in Materials Science and Engineering
[21] D P Bentz ldquoModeling the influence of limestone filler oncement hydration using CEMHYD3Drdquo Cement and ConcreteComposites vol 28 no 2 pp 124ndash129 2006
[22] B Pichler C Hellmich J Eberhardsteiner et al ldquoEffect of gel-space ratio and microstructure on strength of hydrating ce-mentitious materials an engineering micromechanics ap-proachrdquo Cement and Concrete Research vol 45 pp 55ndash682013
[23] M Aqel and D K Panesar ldquoHydration kinetics and com-pressive strength of steam-cured cement pastes and mortarscontaining limestone fillerrdquo Construction and Building Ma-terials vol 113 pp 359ndash368 2016
[24] C-S Poon L Lam S C Kou Y-L Wong and R WongldquoRate of pozzolanic reaction of metakaolin in high-performance cement pastesrdquo Cement and Concrete Re-search vol 31 no 9 pp 1301ndash1306 2001
[25] L Lam Y L Wong and C S Poon ldquoDegree of hydration andgelspace ratio of high-volume fly ashcement systemsrdquo Ce-ment and Concrete Research vol 30 no 5 pp 747ndash756 2000
[26] D Damidot B Lothenbach D Herfort and F P Glasserldquo+ermodynamics and cement sciencerdquo Cement and ConcreteResearch vol 41 no 7 pp 679ndash695 2011
Advances in Materials Science and Engineering 13
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Submit your manuscripts atwwwhindawicom
213 Limestone Reaction Model +e addition of limestonepowder presents the dilution effect nucleation effect andchemical effect on hydration of cement In this study di-lution effect is considered through the amount of capillarywater nucleation effect is considered through a nucleationeffect indicator and chemical effect is considered through alogarithm function with multiple modification factors[18 19]
+e hydration products of cement can form on thesurface of limestone powder +is is called as the nucleationeffect +e nucleation effect indicator of limestone powdercan be written as follows [2]
Lr LS0 lowast SLS
C0 lowast SC (3)
where Lr is the limestone nucleation effect indicator LS0 andC0 are the mass of limestone and cement in mixing pro-portions respectively and SLS and SC are the Blaine surfacearea of limestone powder and cement respectively
In our former study [2] based on the experimentalresults of hydration degree of cement in cement-limestonebinary blends Wang and Luan [2] proposed that the nu-cleation effect of limestone powder can be described asfollows
krLS kr 1 + 12Lr( 1113857 (4)
DeLS De 1 + 12Lr( 1113857 (5)
where krLS is the updated phase boundary reaction co-efficient in cement-limestone blends 12 is enhancing co-efficients of kr [2] DeLS is the updated diffusion coefficient incement-limestone blends and 12 is enhancing coefficientsof De [2]
Until now the experimental results about the reactiondegree of limestone are very limit Tentatively Wang andLuan [2] proposed an empirical model with multi-modification factors for analyzing the reaction degree oflimestone +e empirical model considers the effects ofvarious factors on the chemical reaction of limestone suchas limestone replacement ratios mineral admixtures addi-tions limestone fineness cement fineness water-to-binderratio and curing temperature +e empirical model for thelimestone reaction is shown as follows
αLS1 00087 ln(t)minus 00265 tgt 21 hours (6)
αLS αLS1 lowast m1 lowast m2 lowast m3 lowast m4 lowast m5 lowast m6 (7)
where αLS1 is the reaction degree of limestone in a referencemixture +is reference mixture is Portland cement andlimestone binary blends with a water-to-binder ratio 05 and20 limestone addition cured at 20degC m1 considers the effectof limestone replacement ratios on the reaction degree oflimestone m2 considers the effect of limestone fineness m3considers the effect of cement finenessm4 considers the effectofMK additionm5 considers the effect of the water-to-binderratio and m6 considers the effect of the curing temperatureTable 1 shows the summary of influencing factors of thelimestone reaction As limestone replacement ratio increases
reaction degree of LS decreases While fineness of limestonefineness of cement MK addition and water to binder ratioincrease the reaction degree of LS increases Especially formodification factor m4 1 + (AlMKαMKPAlCαC0) whereAlMK is the aluminum content in MK AlC is the aluminumcontent in cement AlMKαMKP in the numerator is reactedaluminum content from the MK reaction and AlCαC0 indenominator is the reacted aluminum content from the ce-ment reaction Because the aluminum content in MK is muchhigher than that in cement the addition of MK can signifi-cantly improve the reactivity of limestone +e factor m4considers the synergetic effect of limestone and MK A higheraluminum content and a higher reactivity of MK are effectiveto enhance the reactivity of limestone
Summarily this study considers the dilution effectnucleation effect and chemical effect of limestone addi-tions +e enhancement of limestone reactivity due to theaddition of metakaolin is considered through a modifi-cation factor +e influences of other factors such aslimestone replacement ratio fineness of binders andwater-to-binder ratios are also considered in the limestonereaction model
214 Interaction Model among Cement Metakaolin andLimestone In this study the interactions among cementhydration metakaolin reaction and limestone reaction areconsidered through the contents of capillary water andcalcium hydroxide Maekawa et al [13] proposed that as 1 gcement hydrates 04 g capillary water will be consumedDunster et al [20] proposed that as 1 g metakaolin reacts055 g capillary water will be consumed Bentz [21] proposedthat as 1 g limestone reacts 162 g capillary water will beconsumed For hydrating cement-metakaolin-limestoneternary blends the content of capillary water can be de-termined as follows
Wcap W0 minus 04lowastC0 lowast αminus 055 lowast αMK lowast P
minus 162 lowast LS0 lowast αLS(8)
where 04 lowast C0 lowast α 055 lowast αMK lowast P and 162 lowast LS0 lowast αLSare the contents of consumed water from cement hydrationmetakaolin reaction and limestone reaction respectively[13 20 21] +e consumption of capillary water from the 1 glimestone reaction is much higher than those of cement andmetakaolin +is is because the reaction products of lime-stone powder are monocarboaluminate and ettringite whichcontains abundant water
For hydrating cement-metakaolin-limestone ternaryblends the content of calcium hydroxide can be determinedas follows
CH(t) RCHCE lowast C0 lowast αminus vMK lowast αMK lowastP (9)
where RCHCE means the mass of CH produced from thehydration of 1 unit mass of cement and vMK means the massof CH consumed from the reaction of 1 unit mass ofmetakaolin [15] RCHCE lowast C0 lowast α is the mass of CH pro-duced from cement hydration vMK lowast αMK lowast P is the massof CH consumed from the metakaolin reaction
Advances in Materials Science and Engineering 3
Summarily the effect of cement hydration metakaolinreaction and limestone reaction on the contents of capillarywater and calcium hydroxide is considered +e capillarywater content can be used for the cement hydration model(equation (1)) and the calcium hydroxide content can beused for the metakaolin reaction model (equation (2)) Inaddition because the blended hydration model has con-sidered the interactions among cement metakaolin andlimestone reactions the coefficients of the hydration modeldo not vary with different mixtures When the mixtureschange from one to another the coefficients of the hydrationmodel are constant
22 Strength Development Model +e gel-space ratio de-notes the ratio of the volume of binder hydration products tothe sum of volume of hydrated binders and capillary poreFor cement-metakaolin-limestone blends 1ml hydratedcement 1ml reacted metakaolin and 1ml reacted limestoneoccupy 206ml of space [16 22] 252ml space [16 22] and41ml space respectively Reacted products of 1ml lime-stone can occupy much higher space that those of cement(41 vs 206)+is is due to the development of ettringite andmonocarboaluminate from the limestone reaction Con-sidering the reactions of cement metakaolin and limestonethe gel-space ratio of cement-metakaolin-limestone ternary-blended cement can be determined as follows
xc 206 1ρC( 1113857αC0 + 252 1ρMK( 1113857αMKP + 41 1ρLS( 1113857αLSLS0
1ρC( 1113857αC0 + 1ρMK( 1113857αMKP + 1ρLS( 1113857αLSLS0 + W0
(10)
where ρC ρMK and ρLS are densities of cement metakaolinand limestone powder respectively
According to Powersrsquo strength theory the compressivestrength of hydrating concrete can be evaluated using thegel-space ratio as follows
fc(t) Axnc (11)
where fc(t) is the concrete compressive strength A is theintrinsic strength of concrete and n is the strength exponent
For cement-metakaolin-limestone blends cementmetakaolin and limestone will affect the intrinsic strength ofconcrete and strength exponent We assume that the in-trinsic strength of concrete A and strength exponent n is
proportional to the weight fractions of cement metakaolinand limestone in the mixing proportion as follows
A a1 lowastC0
C0 + P + LS0+ a2 lowast
P
C0 + P + LS0
+ a3 lowastLS0
C0 + P + LS0
(12)
n b1 lowastC0
C0 + P + LS0+ b2 lowast
P
C0 + P + LS0
+ b3 lowastLS0
C0 + P + LS0
(13)
where coefficients a1 a2 and a3 in equation (12) representthe contributions of cement metakaolin and limestone tothe intrinsic strength of concrete respectively and the unitsof a1 a2 and a3 are MPa the coefficients b1 b2 and b3 inequation (13) represent the contributions of cement met-akaolin and limestone to the strength exponent re-spectively For neat Portland cement concrete withoutlimestone or metakaolin the strength of concrete onlypertains to a1 and b1 For metakaolin-blended binaryconcrete without limestone the strength of concrete pertainsto coefficients a1 a2 b1 and b2 For ternary-blendedconcrete the strength of concrete pertains to coefficientsa1 a2 a3 b1 b2 and b3+ese coefficients a1 a2 a3 b1 b2and b3 do not change for various mixing proportions ofconcrete
+e flowchart of calculation is proven in Figure 1 Eachtime step the response levels of cement metakaolin andlimestone powder are calculated by utilizing ternary-blendedhydration model +e quantity of CH and capillary water arebased on using reaction levels of binders and concretemixtures In addition the gel-space ratio of hydratingconcrete is decided thinking about the contributions fromreactions of cement metakaolin and limestone reactions Byutilizing Powersrsquo strength theory the compressive strengthof hardening concrete is calculated
3 Verifications of Proposed Models
31 Verification of Hydration Model Experimental resultsfrom Antoni et al [9] are used to verify the proposedblended hydration model and strength development model
Table 1 Summary of influencing factors of the limestone reaction
Factor Equation Influencing trend
Limestone replacement ratios m1 02(LS0(C0 + LS0))As the limestone replacement ratio increases αLS
decreases
Fineness of limestone m2 10131minus 00144 lowast dLS where dLS is an averagediameter of limestone As fineness of limestone increases αLS increases
Fineness of cement m3 055(SCSC1) + 045 where SC1 is the Blainesurface of cement used in the reference study As fineness of cement increases αLS increases
Metakaolin additions m4 1 + (AlMKαMKPAlCαC0) As the MK addition increases αLS increases
Water-to-binder ratios m5 αα05 where α05 is the reaction degreeof cement in the reference study As water-to-binder ratio increases αLS increases
Curing temperature m6 1 Curing temperature does not present significantinfluence on αLS
4 Advances in Materials Science and Engineering
Antoni et al [9] measured the reaction degrees of binder andcompressive strength of cement-MK-LS ternary-blendedconcrete +e chemical compositions of cement meta-kaolin and limestone are shown in Table 2 +e mixingproportions are shown in Table 3 Paste specimens with awater-to-binder ratio of 04 were used for measuring re-action degree of binders Mortar specimens with a water-to-binder ratio of 05 were used for measuring compressivestrength For cement-limestone binary blends the re-placement ratio of limestone was 15 while for cement-metakaolin binary blends the replacement ratio of meta-kaolin was 30 For ternary-blended specimens the sum oflimestone and metakaolin ranged from 15 to 60 and themass ratio of metakaolin to limestone was fixed as 2 +ereaction degrees and strength were measured at the ages of 17 28 and 90 days
+e input parameters of the ternary-blended cementhydration model are concrete mixtures curing temperatureand compound compositions and Blaine surface areas ofbinders By using the blended cement hydration model thereaction degree of MK and LS is calculated and shown inFigure 2
As shown in Figure 2(a) the sequences of the reactiondegree of MK from higher to lower are B15gtB30gtMK30gtB45gtB60 +is can be explained using the MK reactionmodel (equation (2)) As shown in equation (2) the reactiondegree of MKmainly depends on the mass ratio of cement to
MK As the ratio of cement to MK increases the activationeffect from cement hydration is enhanced and reactiondegree of MK increases +e mass ratios of cement to MKwere 85 35 233 183 and 1 in the mixtures of B15 B30MK30 B45 and B60 respectively +e orders of reactiondegree of MK are consistent with the mass ratios of cementto MK
As shown in Figure 2(b) the sequences of reactiondegree of limestone from higher to lower areB15 gt B30 gt B45 gt B60 +e proposed ternary-blendedhydration model can reflect this trend of reaction de-gree of LS In this study the mass ratio of MK to LS internary blends is constant and the difference of the re-action degree of LS is mainly due to the variations of thecement-to-limestone ratio +e mass ratios of cement toLS were 17 7 366 and 2 in the mixtures of B15 B30 B45and B60 respectively As the mass ratio of cement to LSdecreases the reaction degree of LS also decreases (pa-rameter m1 of equation (7)) +e trend of the reactiondegree of LS is consistent with the mass ratio of cement toLS In addition the reaction degree of LS at 1 day is almostzero +is also agrees with our analysis As shown inequation (6) we assumed that the reaction of LS startsafter 21 hours Furthermore the reactivity of LS is verylow At the age of 90 days the reaction degree of LS for B15is 12 which is much lower than cement
Figure 3 shows the parameter analysis of the hydrationmodel Figure 3(a) shows the reaction degree of LS incement-LS binary blends As limestone replacement ratioincreases the reaction degree of limestone decreases Similarto the contents shown in Figure 3(a) Aqel and Panesar [23]
Table 2 Chemical compositions of binders
Cement()
Limestone()
Metakaolin()
SiO2 2101 004 5062Al2O3 463 006 4691Fe2O3 260 005 038CaO 6418 5653 002MgO 182 010 009SO3 278 - 008Na2O 020 004 028K2O 094 004 018TiO2 014 003 129Others 044 002 016Loss on ignition(LOI) 126 4309 000
Total 1000 1000 1000
Table 3 Mixing proportions of specimens [9]
Cement () Limestone () Metakaolin ()PC 100 0 0LS15 85 15 0MK30 70 0 30B15 85 5 10B30 70 10 20B45 55 15 30B60 40 20 40
Setting of initial conditions and calculating time tend
t = t + Δt
t gt tendNo
End
Hydration model
Calculating a degree of hydration
Δα = fce(T t) ΔαMK = fMK(T t) ΔαLS = fLS(T t)
α = α + Δα αMK = αMK + ΔαMK αLS = αLS + ΔαLS
Amount of calcium hydroxideCH(t) = RCHCE lowast C0 lowast α ndash vMK lowast αMK lowast P
Amount of capillary water
Compressive strength
Wcap = W0 ndash 04 lowast C0 lowast α ndash 055 lowast αMK lowast P ndash 162 lowast LS0 lowast αLS
fc(t) = Axcn
Figure 1 Flowchart of simulation
Advances in Materials Science and Engineering 5
also found the reactivity of limestone will be lower with theincreasing of limestone content
Figure 3(b) shows the reaction degree of MK in cement-MK binary blends As MK replacement ratio increases theactivation effect from cement hydration becomes weakerand the reaction degree of MK decreases Similar to thecontents shown in Figure 3(b) Poon et al [24] also foundsimilar results that the reaction degree ofMKwill be lower asthe content of MK increases
Figure 3(c) shows the effect of MK additions on thereaction degree of LS +e addition of MK presents thetwofold effect on reaction of LS First when MK is added toreplace partial cement in the mixtures the mass ratio ofcement to LS decreases which will lower the reaction degreeof LS (this is considered through parameter m1 of equation(7)) However the aluminum content in MK (46) is aboutten times of the aluminum content in cement (46) +eaddition of MK will enhance the reaction of LS (this isconsidered through parameter m4 of equation (7)) Becausethe enhancing effect is much more significant than thelowering effect the addition of MK can increase the reactiondegree of limestone (shown in Figure 3(c)) Similar to thecontents shown in Figure 3(c) many researchers [4 9] alsoexperimentally found that reactivity of limestone can beimproved due to MK addition
Figure 3(d) shows the effect of metakaolin and limestonecontents on the reaction degree of cement When meta-kaolin and limestone are used to replace partial cement thereaction degree of cement is improved due to the dilutioneffect and nucleation effect (the dilution effect is consideredthrough parameter λ2 in equation (1) and the nucleationeffect is considered through equations (4) and (5)) Similarto the contents shown in Figure 3(d) Lam et al [25] alsofound that the addition of mineral admixtures can improvethe reaction degree of cement
32VerificationofStrengthDevelopmentModel By using thecement-MK-LS ternary-blended hydration model the gel-space ratio of hydrating concrete can be calculated (equation(10)) Furthermore based on the strength of concrete atdifferent ages the values of strength coefficients of a1 a2and a3 and b1 b2 and b3 can be calibrated (a1 140MPaa2 258MPa a3120MPa b1 385 b2113 andb3134) +ese coefficients do not vary with concretemixtures+e values of a1 and b1 relate to cement hydrationthe values of a2 and b2 relate to the metakaolin reaction andthe values of a3 and b3 relate to the limestone reaction Forcement-metakaolin binary blends the development ofstrength relates to a1 a2 b1 and b2 For cement-limestonebinary blends the development of strength relates to a1 a3b1 and b3 For cement-metakaolin-limestone ternaryblends the development of strength relates to a1 a2 a3 b1b2 and b3 +e analyzed results of compressive strength areshown in Figure 4 +e analysis results generally agree withexperimental results At the ages of 28 days the B15 concrete(cement 85+metakaolin 10+ limestone 5) has ahighest strength than other mixtures +is may be because ofthe synergetic effect of metakaolin and limestone
Because the strength coefficients of strength evaluationequation are constants for different concrete mixtures wecan make parameter analysis for different concrete mixturesFigure 5(a) shows the strength development of cement-limestone binary blends At the early age due to the nu-cleation effect the strength of limestone blends concreteshows higher strength than control concrete While at lateages due to the dilution effect the strength of limestoneblends concrete is lower than control concrete As thecontents of limestone increases from 10 to 20 the late-age strength decreases +e trend shown in Figure 5(a)agrees with Bonavetti et alrsquos [19] studies about strengthdevelopment of limestone-blended concrete
Time (hours)
08
06
04
02
0
Reac
tion
degr
ee o
f MK
100 102
MK30B15-MK10LS5B30-MK20LS10B45-MK30LS15B60-MK40LS20
Exper-MK30Exper-B15Exper-B30Exper-B45Exper-B60
(a)
100 102
Time (hours)
0
005
01
015
02
025
03
Reac
tion
degr
ee o
f lim
esto
ne p
owde
r
B15-MK10LS5B30-MK20LS10B45-MK30LS15B60-MK40LS20
Exper-B15Exper-B30Exper-B45Exper-B60
(b)
Figure 2 Verification of the hydration model (a) reaction degree of MK (b) reaction degree of LS
6 Advances in Materials Science and Engineering
Figure 5(b) shows the strength development of cement-metakaolin binary blends Metakaolin-blended concrete hasa higher strength than control concrete As the contents ofmetakaolin increases from 5 to 10 the strength alsoincreases +e trend shown in Figure 5(b) agrees with Poonet alrsquos [24] studies about strength development ofmetakaolin-blended concrete
Damidot et al [26] studies the strength development of70 cement + 30 clay-limestone ternary blends +e sumof clay and limestone was fixed as 30 and the weightfraction of clay(clay + limestone) ranges from 0 to 100[26] Damidot et al [26] found that at the age of 28 days themix with 70metakaolin has the highest strength than othermixes +is is because of the synergetic effect of limestoneand metakaolin [26] Based on the proposed strength de-velopment in this study we make parameter analysis of
strength development for 70 cement + 30 clay-limestoneternary blends In our analysis the sum of clay and limestoneis also fixed as 30 the weight fractions of clay(clay + limestone) are given as 0 25 50 75 and 100and the ages of parameter analysis are 15 days 3 days28 days and 90 days respectively +e results of parameteranalysis are shown in Figures 6(a)ndash6(d) As shown inFigure 6(a) at the age of 15 days the strength of blendedconcrete is higher than base Portland cement+is is becauseof the nucleation effect of limestone While as shown inFigures 6(b)ndash6(d) at the age of 3 days 28 days and 90 dayswhen the mk(mk + limestone) equals to zero (the content ofmetakaolin is zero and binder consists of 30 limestone and70 cement) the strength of limestone-blended concreteis lower than base Portland cement +is is because ofthe dilution effect of limestone While for other mk
0 500 1000 1500 2000 2500Time (hours)
0
001
002
003
004
005
006
007Re
actio
n de
gree
of l
imes
tone
Cement 95 + limestone 5Cement 90 + limestone 10Cement 85 + limestone 15
(a)
0 500 1000 1500 2000 2500Time (hours)
0
02
04
06
08
Reac
tion
degr
ee o
f MK
Cement 95 + MK5Cement 90 + MK10Cement 80 + MK20
(b)
0 500 1000 1500 2000 2500Time (hours)
0
001
002
003
004
005
006
007
Reac
tion
degr
ee o
f lim
esto
ne
Cement 55 + MK30 + LS15Cement 85 + MK0 + LS15
(c)
0 500 1000 1500 2000 2500Time (hours)
0
02
04
06
08
1Re
actio
n de
gree
of c
emen
t
ControlB60-MK40LS20
(d)
Figure 3 Parameter analysis of reaction degree of binders (a) effect of limestone contents on the reaction degree of limestone (b) effect ofmetakaolin contents on the reaction degree of metakaolin (c) effect of metakaolin contents on the reaction degree of limestone (d) effect ofmetakaolin and limestone contents on the reaction degree of cement
Advances in Materials Science and Engineering 7
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70C
ompr
essiv
e stre
ngth
(MPa
)
Analysis resultsExperimental results
Control
(a)
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
Analysis resultsExperimental results
(b)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
(c)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70C
ompr
essiv
e stre
ngth
(MPa
)MK 10 limestone 5
(d)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 20 limestone 10
(e)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 30 limestone 20
(f )
Figure 4 Continued
8 Advances in Materials Science and Engineering
(mk+ limestone) ratios of 25 50 75 and 100 be-cause the reaction of metakaolin can contribute to thestrength the strength of blended concrete is higher than basePortland cement
At the age of 15 days 3 days 28 days and 90 days theoptimum weight fractions of clay(clay + limestone) are 2550 75 and 75 respectively (shown in Figures 6(e)) Ouranalysis result about optimum weight fraction of clay(clay + limestone) is similar to that of Damidot et al [26]studies In addition our analysis shows that at the ages of15 days 3 days 28 days and 90 days the optimum weightfraction of limestone(clay + limestone) is 75 50 25 and25 respectively It means that at the early age limestone iseffective to improve the strength of concrete (this is because of
the nucleation effect of limestone) and at the late agemetakaolin is effective to improve the strength of concrete(this is because of the pozzolanic reaction of metakaolin)
In Figure 6 the sum of metakaolin and limestone isfixed as 30 To find the optimum combinations of ce-ment metakaolin and limestone we make much widerparameter analysis In this wider parameter analysis thesum of metakaolin and limestone is not a fixed value +econtents of metakaolin vary from 0 to 30 and thecontents of limestone vary from 0 to 20 +e analysisresults of isoline of strength are shown in Figures 7(a)ndash7(d) At the early age 15 days the concrete with a higherlimestone content and a lower metakaolin content hashighest strength (shown in Figure 7(a)) while at the late
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 40 limestone 20
(g)
Figure 4 Analysis of compressive strength (a) PC (b) LS15 (c) MK30 (d) B15 (e) B30 (f ) B45 (g) B60
10ndash2 100 102 104
Time (hours)
0
10
20
30
40
50
60
Com
pres
sive s
treng
th (M
Pa)
ControlLS10LS20
(a)
ControlMK5MK10
10ndash2 100 102 104
Time (hours)
0
20
40
60
80
Com
pres
sive s
treng
th (M
Pa)
(b)
Figure 5 Effect of LS and MK on strength development (a) cement-LS binary blends (b) cement-MK binary blends
Advances in Materials Science and Engineering 9
0 02 04 06 08 1MK(MK + limestone) weight fraction
19
195
20
205
21
215
221
5-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
Metakaolin + limestoneBase Portland cement
(a)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
25
26
27
28
29
30
3-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(b)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
35
40
45
50
55
60
28-d
ay co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(c)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
45
50
55
60
65
7090
-day
com
pres
sive s
treng
th (M
Pa)
70 PC + 30 (MK-limestone mix)
(d)
0 20 40 60 80 100Time (days)
02
03
04
05
06
07
08
Opt
imum
wei
ght f
ract
ion
in M
K +
limes
tone
ble
nds
70 PC + 30 (MK-limestone mix)
MK
(e)
Figure 6 Synergetic effect of cement-MK-LS ternary blends (MK+LS 30) (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimumfractions of MK
10 Advances in Materials Science and Engineering
age of 90 days the concrete with a higher metakaolincontent and a lower limestone content has higheststrength (shown in Figure 7(d)) In other words toachieve the highest strength of cement-metakaolin-limestone ternary blends the optimum combination ofmetakaolin and limestone is dependent on ages From theearly age to late age the optimum combinations change
shift from high limestone-low metakaolin zone to lowlimestone-high metakaolin zone (shown in Figure 7(e))
4 Conclusions
+is study presents an integrated hydration-strength modelfor cement-limestone-metakaolin ternary blends
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03M
K w
eigh
t fra
ctio
n in
tota
l bin
der
195
20
205
21
215
(a)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
265
27
275
28
285
29
295
(b)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
44
46
48
50
52
54
56
(c)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
52
54
56
58
60
62
64
66
68
(d)
008 01 012 014 016 018MK weight fraction in total binder
0
005
01
015
02
Lim
esto
ne w
eigh
t fra
ctio
n in
tota
l bin
der
15 days
3 days
28 days and90 days
(e)
Figure 7 Analysis of optimum MK and LS combinations (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimum MK and LScombinations at different ages
Advances in Materials Science and Engineering 11
First a cement hydration model a metakaolin reactionmodel and a limestone reaction model are proposed in theternary-blended hydration model Pozzolanic reaction ofmetakaolin chemical and physics effect of limestone andsynergetic effect between metakaolin and limestone aredetailed considered in the ternary-blended hydration modelMoreover the interactions among cement hydrationlimestone reaction and metakaolin reaction are consideredthrough the contents of calcium hydroxide and capillarywater+e coefficients of the hydration model do not changefor various concrete mixtures
Second based on the hydration model the gel-spaceratio of hydrating blends is calculated considering thecontributions from the reactions of cement metakaolin andlimestone Furthermore the strength development of ter-nary blends is evaluated using the gel-space ratio +e co-efficients of the strength model do not change for variousconcrete mixtures Based on parameter analysis the syn-ergetic effect on strength development is shown and theoptimal combinations of cement-limestone-metakaolinternary blends are determined From the early age to lateage the optimum combinations of ternary blends shift fromhigh limestone-low metakaolin zone to low limestone-highmetakaolin zone
Data Availability
+e data used to support the findings of this study are in-cluded within the article
Conflicts of Interest
+e author declares that there are no conflicts of interestregarding the publication of this paper
Acknowledgments
+is research was supported by Basic Science ResearchProgram through the National Research Foundation ofKorea (NRF) funded by the Ministry of Science ICT andFuture Planning (no 2015R1A5A1037548) and a NRF grant(NRF-2017R1C1B1010076)
References
[1] X-Y Wang ldquoModeling of hydration compressive strengthand carbonation of Portland-limestone cement (PLC) con-creterdquo Materials vol 10 no 2 pp 115ndash131 2017
[2] X Y Wang and Y Luan ldquoModeling of hydration strengthdevelopment and optimum combinations of cement-slag-limestone ternary concreterdquo International Journal of Con-crete Structures and Materials vol 12 no 1 pp 193ndash2062018
[3] K Vance A Kumar G Sant and N Neithalath ldquo+e rhe-ological properties of ternary binders containing Portlandcement limestone and metakaolin or fly ashrdquo Cement andConcrete Research vol 52 pp 196ndash207 2013
[4] K Vance M Aguayo T Oey G Sant and N NeithalathldquoHydration and strength development in ternary portlandcement blends containing limestone and fly ash or
metakaolinrdquo Cement and Concrete Composites vol 39pp 93ndash103 2013
[5] G L Alvarez A Nazari A Bagheri J G Sanjayan andC De Lange ldquoMicrostructure electrical and mechanicalproperties of steel fibres reinforced cement mortars withpartial metakaolin and limestone additionrdquo Construction andBuilding Materials vol 135 pp 8ndash20 2017
[6] A M Ramezanianpour and R D Hooton ldquoA study on hy-dration compressive strength and porosity of Portland-limestone cement mixes containing SCMsrdquo Cement andConcrete Composites vol 51 pp 1ndash13 2014
[7] C Perlot P Rougeau and S Dehaudt ldquoSlurry of metakaolincombined with limestone addition for self-compacted con-crete application for precast industryrdquo Cement and ConcreteComposites vol 44 pp 50ndash57 2013
[8] K Sotiriadis E Nikolopoulou S Tsivilis A PavlouE Chaniotakis and R N Swamy ldquo+e effect of chlorides onthe thaumasite form of sulfate attack of limestone cementconcrete containing mineral admixtures at low temperaturerdquoConstruction and Building Materials vol 43 pp 156ndash1642013
[9] M Antoni J Rossen F Martirena and K Scrivener ldquoCementsubstitution by a combination of metakaolin and limestonerdquoCement and Concrete Research vol 42 no 12 pp 1579ndash15892012
[10] Z Shi M R Geiker K De Weerdt et al ldquoRole of calcium onchloride binding in hydrated Portland cement-metakaolin-limestone blendsrdquo Cement and Concrete Research vol 95pp 205ndash216 2017
[11] Z Shi B Lothenbach M R Geiker et al ldquoExperimentalstudies and thermodynamic modeling of the carbonation ofPortland cement metakaolin and limestonemortarsrdquo Cementand Concrete Research vol 88 pp 60ndash72 2016
[12] X-Y Wang and H-S Lee ldquoModeling the hydration ofconcrete incorporating fly ash or slagrdquo Cement and ConcreteResearch vol 40 no 7 pp 984ndash996 2010
[13] K Maekawa R Chaube and T Kishi Modelling of ConcretePerformance Hydration Microstructure and Mass TransportCRC Press London UK 1999
[14] K van Breugel Simulation of Hydration and Formation ofStructure in Hardening Cement-Based Materials Delft Uni-versity Press Delft Netherlands 1997
[15] X-Y Wang ldquoAnalysis of hydration-mechanical-durabilityproperties of metakaolin blended concreterdquo Applied Sci-ences vol 7 no 10 pp 1087ndash1102 2017
[16] V G Papadakis ldquoExperimental investigation and theoreticalmodeling of silica fume activity in concreterdquo Cement andConcrete Research vol 29 no 1 pp 79ndash86 1999
[17] Y Elakneswaran E Owaki S Miyahara M OginoT Maruya and T Nawa ldquoHydration study of slag-blendedcement based on thermodynamic considerationsrdquo Con-struction and Building Materials vol 124 pp 615ndash625 2016
[18] T Vuk V Tinta R Gabrovsek and V Kaucic ldquo+e effects oflimestone addition clinker type and fineness on properties ofPortland cementrdquo Cement and Concrete Research vol 31no 1 pp 135ndash139 2001
[19] V Bonavetti H Donza G Menendez O Cabrera andE F Irassar ldquoLimestone filler cement in low wc concrete arational use of energyrdquo Cement and Concrete Researchvol 33 no 6 pp 865ndash871 2003
[20] A M Dunster J R Parsonage and M J K +omas ldquo+epozzolanic reaction of metakaolinite and its effects onPortland cement hydrationrdquo Journal of Materials Sciencevol 28 no 5 pp 1345ndash1350 1993
12 Advances in Materials Science and Engineering
[21] D P Bentz ldquoModeling the influence of limestone filler oncement hydration using CEMHYD3Drdquo Cement and ConcreteComposites vol 28 no 2 pp 124ndash129 2006
[22] B Pichler C Hellmich J Eberhardsteiner et al ldquoEffect of gel-space ratio and microstructure on strength of hydrating ce-mentitious materials an engineering micromechanics ap-proachrdquo Cement and Concrete Research vol 45 pp 55ndash682013
[23] M Aqel and D K Panesar ldquoHydration kinetics and com-pressive strength of steam-cured cement pastes and mortarscontaining limestone fillerrdquo Construction and Building Ma-terials vol 113 pp 359ndash368 2016
[24] C-S Poon L Lam S C Kou Y-L Wong and R WongldquoRate of pozzolanic reaction of metakaolin in high-performance cement pastesrdquo Cement and Concrete Re-search vol 31 no 9 pp 1301ndash1306 2001
[25] L Lam Y L Wong and C S Poon ldquoDegree of hydration andgelspace ratio of high-volume fly ashcement systemsrdquo Ce-ment and Concrete Research vol 30 no 5 pp 747ndash756 2000
[26] D Damidot B Lothenbach D Herfort and F P Glasserldquo+ermodynamics and cement sciencerdquo Cement and ConcreteResearch vol 41 no 7 pp 679ndash695 2011
Advances in Materials Science and Engineering 13
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Summarily the effect of cement hydration metakaolinreaction and limestone reaction on the contents of capillarywater and calcium hydroxide is considered +e capillarywater content can be used for the cement hydration model(equation (1)) and the calcium hydroxide content can beused for the metakaolin reaction model (equation (2)) Inaddition because the blended hydration model has con-sidered the interactions among cement metakaolin andlimestone reactions the coefficients of the hydration modeldo not vary with different mixtures When the mixtureschange from one to another the coefficients of the hydrationmodel are constant
22 Strength Development Model +e gel-space ratio de-notes the ratio of the volume of binder hydration products tothe sum of volume of hydrated binders and capillary poreFor cement-metakaolin-limestone blends 1ml hydratedcement 1ml reacted metakaolin and 1ml reacted limestoneoccupy 206ml of space [16 22] 252ml space [16 22] and41ml space respectively Reacted products of 1ml lime-stone can occupy much higher space that those of cement(41 vs 206)+is is due to the development of ettringite andmonocarboaluminate from the limestone reaction Con-sidering the reactions of cement metakaolin and limestonethe gel-space ratio of cement-metakaolin-limestone ternary-blended cement can be determined as follows
xc 206 1ρC( 1113857αC0 + 252 1ρMK( 1113857αMKP + 41 1ρLS( 1113857αLSLS0
1ρC( 1113857αC0 + 1ρMK( 1113857αMKP + 1ρLS( 1113857αLSLS0 + W0
(10)
where ρC ρMK and ρLS are densities of cement metakaolinand limestone powder respectively
According to Powersrsquo strength theory the compressivestrength of hydrating concrete can be evaluated using thegel-space ratio as follows
fc(t) Axnc (11)
where fc(t) is the concrete compressive strength A is theintrinsic strength of concrete and n is the strength exponent
For cement-metakaolin-limestone blends cementmetakaolin and limestone will affect the intrinsic strength ofconcrete and strength exponent We assume that the in-trinsic strength of concrete A and strength exponent n is
proportional to the weight fractions of cement metakaolinand limestone in the mixing proportion as follows
A a1 lowastC0
C0 + P + LS0+ a2 lowast
P
C0 + P + LS0
+ a3 lowastLS0
C0 + P + LS0
(12)
n b1 lowastC0
C0 + P + LS0+ b2 lowast
P
C0 + P + LS0
+ b3 lowastLS0
C0 + P + LS0
(13)
where coefficients a1 a2 and a3 in equation (12) representthe contributions of cement metakaolin and limestone tothe intrinsic strength of concrete respectively and the unitsof a1 a2 and a3 are MPa the coefficients b1 b2 and b3 inequation (13) represent the contributions of cement met-akaolin and limestone to the strength exponent re-spectively For neat Portland cement concrete withoutlimestone or metakaolin the strength of concrete onlypertains to a1 and b1 For metakaolin-blended binaryconcrete without limestone the strength of concrete pertainsto coefficients a1 a2 b1 and b2 For ternary-blendedconcrete the strength of concrete pertains to coefficientsa1 a2 a3 b1 b2 and b3+ese coefficients a1 a2 a3 b1 b2and b3 do not change for various mixing proportions ofconcrete
+e flowchart of calculation is proven in Figure 1 Eachtime step the response levels of cement metakaolin andlimestone powder are calculated by utilizing ternary-blendedhydration model +e quantity of CH and capillary water arebased on using reaction levels of binders and concretemixtures In addition the gel-space ratio of hydratingconcrete is decided thinking about the contributions fromreactions of cement metakaolin and limestone reactions Byutilizing Powersrsquo strength theory the compressive strengthof hardening concrete is calculated
3 Verifications of Proposed Models
31 Verification of Hydration Model Experimental resultsfrom Antoni et al [9] are used to verify the proposedblended hydration model and strength development model
Table 1 Summary of influencing factors of the limestone reaction
Factor Equation Influencing trend
Limestone replacement ratios m1 02(LS0(C0 + LS0))As the limestone replacement ratio increases αLS
decreases
Fineness of limestone m2 10131minus 00144 lowast dLS where dLS is an averagediameter of limestone As fineness of limestone increases αLS increases
Fineness of cement m3 055(SCSC1) + 045 where SC1 is the Blainesurface of cement used in the reference study As fineness of cement increases αLS increases
Metakaolin additions m4 1 + (AlMKαMKPAlCαC0) As the MK addition increases αLS increases
Water-to-binder ratios m5 αα05 where α05 is the reaction degreeof cement in the reference study As water-to-binder ratio increases αLS increases
Curing temperature m6 1 Curing temperature does not present significantinfluence on αLS
4 Advances in Materials Science and Engineering
Antoni et al [9] measured the reaction degrees of binder andcompressive strength of cement-MK-LS ternary-blendedconcrete +e chemical compositions of cement meta-kaolin and limestone are shown in Table 2 +e mixingproportions are shown in Table 3 Paste specimens with awater-to-binder ratio of 04 were used for measuring re-action degree of binders Mortar specimens with a water-to-binder ratio of 05 were used for measuring compressivestrength For cement-limestone binary blends the re-placement ratio of limestone was 15 while for cement-metakaolin binary blends the replacement ratio of meta-kaolin was 30 For ternary-blended specimens the sum oflimestone and metakaolin ranged from 15 to 60 and themass ratio of metakaolin to limestone was fixed as 2 +ereaction degrees and strength were measured at the ages of 17 28 and 90 days
+e input parameters of the ternary-blended cementhydration model are concrete mixtures curing temperatureand compound compositions and Blaine surface areas ofbinders By using the blended cement hydration model thereaction degree of MK and LS is calculated and shown inFigure 2
As shown in Figure 2(a) the sequences of the reactiondegree of MK from higher to lower are B15gtB30gtMK30gtB45gtB60 +is can be explained using the MK reactionmodel (equation (2)) As shown in equation (2) the reactiondegree of MKmainly depends on the mass ratio of cement to
MK As the ratio of cement to MK increases the activationeffect from cement hydration is enhanced and reactiondegree of MK increases +e mass ratios of cement to MKwere 85 35 233 183 and 1 in the mixtures of B15 B30MK30 B45 and B60 respectively +e orders of reactiondegree of MK are consistent with the mass ratios of cementto MK
As shown in Figure 2(b) the sequences of reactiondegree of limestone from higher to lower areB15 gt B30 gt B45 gt B60 +e proposed ternary-blendedhydration model can reflect this trend of reaction de-gree of LS In this study the mass ratio of MK to LS internary blends is constant and the difference of the re-action degree of LS is mainly due to the variations of thecement-to-limestone ratio +e mass ratios of cement toLS were 17 7 366 and 2 in the mixtures of B15 B30 B45and B60 respectively As the mass ratio of cement to LSdecreases the reaction degree of LS also decreases (pa-rameter m1 of equation (7)) +e trend of the reactiondegree of LS is consistent with the mass ratio of cement toLS In addition the reaction degree of LS at 1 day is almostzero +is also agrees with our analysis As shown inequation (6) we assumed that the reaction of LS startsafter 21 hours Furthermore the reactivity of LS is verylow At the age of 90 days the reaction degree of LS for B15is 12 which is much lower than cement
Figure 3 shows the parameter analysis of the hydrationmodel Figure 3(a) shows the reaction degree of LS incement-LS binary blends As limestone replacement ratioincreases the reaction degree of limestone decreases Similarto the contents shown in Figure 3(a) Aqel and Panesar [23]
Table 2 Chemical compositions of binders
Cement()
Limestone()
Metakaolin()
SiO2 2101 004 5062Al2O3 463 006 4691Fe2O3 260 005 038CaO 6418 5653 002MgO 182 010 009SO3 278 - 008Na2O 020 004 028K2O 094 004 018TiO2 014 003 129Others 044 002 016Loss on ignition(LOI) 126 4309 000
Total 1000 1000 1000
Table 3 Mixing proportions of specimens [9]
Cement () Limestone () Metakaolin ()PC 100 0 0LS15 85 15 0MK30 70 0 30B15 85 5 10B30 70 10 20B45 55 15 30B60 40 20 40
Setting of initial conditions and calculating time tend
t = t + Δt
t gt tendNo
End
Hydration model
Calculating a degree of hydration
Δα = fce(T t) ΔαMK = fMK(T t) ΔαLS = fLS(T t)
α = α + Δα αMK = αMK + ΔαMK αLS = αLS + ΔαLS
Amount of calcium hydroxideCH(t) = RCHCE lowast C0 lowast α ndash vMK lowast αMK lowast P
Amount of capillary water
Compressive strength
Wcap = W0 ndash 04 lowast C0 lowast α ndash 055 lowast αMK lowast P ndash 162 lowast LS0 lowast αLS
fc(t) = Axcn
Figure 1 Flowchart of simulation
Advances in Materials Science and Engineering 5
also found the reactivity of limestone will be lower with theincreasing of limestone content
Figure 3(b) shows the reaction degree of MK in cement-MK binary blends As MK replacement ratio increases theactivation effect from cement hydration becomes weakerand the reaction degree of MK decreases Similar to thecontents shown in Figure 3(b) Poon et al [24] also foundsimilar results that the reaction degree ofMKwill be lower asthe content of MK increases
Figure 3(c) shows the effect of MK additions on thereaction degree of LS +e addition of MK presents thetwofold effect on reaction of LS First when MK is added toreplace partial cement in the mixtures the mass ratio ofcement to LS decreases which will lower the reaction degreeof LS (this is considered through parameter m1 of equation(7)) However the aluminum content in MK (46) is aboutten times of the aluminum content in cement (46) +eaddition of MK will enhance the reaction of LS (this isconsidered through parameter m4 of equation (7)) Becausethe enhancing effect is much more significant than thelowering effect the addition of MK can increase the reactiondegree of limestone (shown in Figure 3(c)) Similar to thecontents shown in Figure 3(c) many researchers [4 9] alsoexperimentally found that reactivity of limestone can beimproved due to MK addition
Figure 3(d) shows the effect of metakaolin and limestonecontents on the reaction degree of cement When meta-kaolin and limestone are used to replace partial cement thereaction degree of cement is improved due to the dilutioneffect and nucleation effect (the dilution effect is consideredthrough parameter λ2 in equation (1) and the nucleationeffect is considered through equations (4) and (5)) Similarto the contents shown in Figure 3(d) Lam et al [25] alsofound that the addition of mineral admixtures can improvethe reaction degree of cement
32VerificationofStrengthDevelopmentModel By using thecement-MK-LS ternary-blended hydration model the gel-space ratio of hydrating concrete can be calculated (equation(10)) Furthermore based on the strength of concrete atdifferent ages the values of strength coefficients of a1 a2and a3 and b1 b2 and b3 can be calibrated (a1 140MPaa2 258MPa a3120MPa b1 385 b2113 andb3134) +ese coefficients do not vary with concretemixtures+e values of a1 and b1 relate to cement hydrationthe values of a2 and b2 relate to the metakaolin reaction andthe values of a3 and b3 relate to the limestone reaction Forcement-metakaolin binary blends the development ofstrength relates to a1 a2 b1 and b2 For cement-limestonebinary blends the development of strength relates to a1 a3b1 and b3 For cement-metakaolin-limestone ternaryblends the development of strength relates to a1 a2 a3 b1b2 and b3 +e analyzed results of compressive strength areshown in Figure 4 +e analysis results generally agree withexperimental results At the ages of 28 days the B15 concrete(cement 85+metakaolin 10+ limestone 5) has ahighest strength than other mixtures +is may be because ofthe synergetic effect of metakaolin and limestone
Because the strength coefficients of strength evaluationequation are constants for different concrete mixtures wecan make parameter analysis for different concrete mixturesFigure 5(a) shows the strength development of cement-limestone binary blends At the early age due to the nu-cleation effect the strength of limestone blends concreteshows higher strength than control concrete While at lateages due to the dilution effect the strength of limestoneblends concrete is lower than control concrete As thecontents of limestone increases from 10 to 20 the late-age strength decreases +e trend shown in Figure 5(a)agrees with Bonavetti et alrsquos [19] studies about strengthdevelopment of limestone-blended concrete
Time (hours)
08
06
04
02
0
Reac
tion
degr
ee o
f MK
100 102
MK30B15-MK10LS5B30-MK20LS10B45-MK30LS15B60-MK40LS20
Exper-MK30Exper-B15Exper-B30Exper-B45Exper-B60
(a)
100 102
Time (hours)
0
005
01
015
02
025
03
Reac
tion
degr
ee o
f lim
esto
ne p
owde
r
B15-MK10LS5B30-MK20LS10B45-MK30LS15B60-MK40LS20
Exper-B15Exper-B30Exper-B45Exper-B60
(b)
Figure 2 Verification of the hydration model (a) reaction degree of MK (b) reaction degree of LS
6 Advances in Materials Science and Engineering
Figure 5(b) shows the strength development of cement-metakaolin binary blends Metakaolin-blended concrete hasa higher strength than control concrete As the contents ofmetakaolin increases from 5 to 10 the strength alsoincreases +e trend shown in Figure 5(b) agrees with Poonet alrsquos [24] studies about strength development ofmetakaolin-blended concrete
Damidot et al [26] studies the strength development of70 cement + 30 clay-limestone ternary blends +e sumof clay and limestone was fixed as 30 and the weightfraction of clay(clay + limestone) ranges from 0 to 100[26] Damidot et al [26] found that at the age of 28 days themix with 70metakaolin has the highest strength than othermixes +is is because of the synergetic effect of limestoneand metakaolin [26] Based on the proposed strength de-velopment in this study we make parameter analysis of
strength development for 70 cement + 30 clay-limestoneternary blends In our analysis the sum of clay and limestoneis also fixed as 30 the weight fractions of clay(clay + limestone) are given as 0 25 50 75 and 100and the ages of parameter analysis are 15 days 3 days28 days and 90 days respectively +e results of parameteranalysis are shown in Figures 6(a)ndash6(d) As shown inFigure 6(a) at the age of 15 days the strength of blendedconcrete is higher than base Portland cement+is is becauseof the nucleation effect of limestone While as shown inFigures 6(b)ndash6(d) at the age of 3 days 28 days and 90 dayswhen the mk(mk + limestone) equals to zero (the content ofmetakaolin is zero and binder consists of 30 limestone and70 cement) the strength of limestone-blended concreteis lower than base Portland cement +is is because ofthe dilution effect of limestone While for other mk
0 500 1000 1500 2000 2500Time (hours)
0
001
002
003
004
005
006
007Re
actio
n de
gree
of l
imes
tone
Cement 95 + limestone 5Cement 90 + limestone 10Cement 85 + limestone 15
(a)
0 500 1000 1500 2000 2500Time (hours)
0
02
04
06
08
Reac
tion
degr
ee o
f MK
Cement 95 + MK5Cement 90 + MK10Cement 80 + MK20
(b)
0 500 1000 1500 2000 2500Time (hours)
0
001
002
003
004
005
006
007
Reac
tion
degr
ee o
f lim
esto
ne
Cement 55 + MK30 + LS15Cement 85 + MK0 + LS15
(c)
0 500 1000 1500 2000 2500Time (hours)
0
02
04
06
08
1Re
actio
n de
gree
of c
emen
t
ControlB60-MK40LS20
(d)
Figure 3 Parameter analysis of reaction degree of binders (a) effect of limestone contents on the reaction degree of limestone (b) effect ofmetakaolin contents on the reaction degree of metakaolin (c) effect of metakaolin contents on the reaction degree of limestone (d) effect ofmetakaolin and limestone contents on the reaction degree of cement
Advances in Materials Science and Engineering 7
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70C
ompr
essiv
e stre
ngth
(MPa
)
Analysis resultsExperimental results
Control
(a)
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
Analysis resultsExperimental results
(b)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
(c)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70C
ompr
essiv
e stre
ngth
(MPa
)MK 10 limestone 5
(d)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 20 limestone 10
(e)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 30 limestone 20
(f )
Figure 4 Continued
8 Advances in Materials Science and Engineering
(mk+ limestone) ratios of 25 50 75 and 100 be-cause the reaction of metakaolin can contribute to thestrength the strength of blended concrete is higher than basePortland cement
At the age of 15 days 3 days 28 days and 90 days theoptimum weight fractions of clay(clay + limestone) are 2550 75 and 75 respectively (shown in Figures 6(e)) Ouranalysis result about optimum weight fraction of clay(clay + limestone) is similar to that of Damidot et al [26]studies In addition our analysis shows that at the ages of15 days 3 days 28 days and 90 days the optimum weightfraction of limestone(clay + limestone) is 75 50 25 and25 respectively It means that at the early age limestone iseffective to improve the strength of concrete (this is because of
the nucleation effect of limestone) and at the late agemetakaolin is effective to improve the strength of concrete(this is because of the pozzolanic reaction of metakaolin)
In Figure 6 the sum of metakaolin and limestone isfixed as 30 To find the optimum combinations of ce-ment metakaolin and limestone we make much widerparameter analysis In this wider parameter analysis thesum of metakaolin and limestone is not a fixed value +econtents of metakaolin vary from 0 to 30 and thecontents of limestone vary from 0 to 20 +e analysisresults of isoline of strength are shown in Figures 7(a)ndash7(d) At the early age 15 days the concrete with a higherlimestone content and a lower metakaolin content hashighest strength (shown in Figure 7(a)) while at the late
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 40 limestone 20
(g)
Figure 4 Analysis of compressive strength (a) PC (b) LS15 (c) MK30 (d) B15 (e) B30 (f ) B45 (g) B60
10ndash2 100 102 104
Time (hours)
0
10
20
30
40
50
60
Com
pres
sive s
treng
th (M
Pa)
ControlLS10LS20
(a)
ControlMK5MK10
10ndash2 100 102 104
Time (hours)
0
20
40
60
80
Com
pres
sive s
treng
th (M
Pa)
(b)
Figure 5 Effect of LS and MK on strength development (a) cement-LS binary blends (b) cement-MK binary blends
Advances in Materials Science and Engineering 9
0 02 04 06 08 1MK(MK + limestone) weight fraction
19
195
20
205
21
215
221
5-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
Metakaolin + limestoneBase Portland cement
(a)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
25
26
27
28
29
30
3-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(b)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
35
40
45
50
55
60
28-d
ay co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(c)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
45
50
55
60
65
7090
-day
com
pres
sive s
treng
th (M
Pa)
70 PC + 30 (MK-limestone mix)
(d)
0 20 40 60 80 100Time (days)
02
03
04
05
06
07
08
Opt
imum
wei
ght f
ract
ion
in M
K +
limes
tone
ble
nds
70 PC + 30 (MK-limestone mix)
MK
(e)
Figure 6 Synergetic effect of cement-MK-LS ternary blends (MK+LS 30) (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimumfractions of MK
10 Advances in Materials Science and Engineering
age of 90 days the concrete with a higher metakaolincontent and a lower limestone content has higheststrength (shown in Figure 7(d)) In other words toachieve the highest strength of cement-metakaolin-limestone ternary blends the optimum combination ofmetakaolin and limestone is dependent on ages From theearly age to late age the optimum combinations change
shift from high limestone-low metakaolin zone to lowlimestone-high metakaolin zone (shown in Figure 7(e))
4 Conclusions
+is study presents an integrated hydration-strength modelfor cement-limestone-metakaolin ternary blends
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03M
K w
eigh
t fra
ctio
n in
tota
l bin
der
195
20
205
21
215
(a)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
265
27
275
28
285
29
295
(b)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
44
46
48
50
52
54
56
(c)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
52
54
56
58
60
62
64
66
68
(d)
008 01 012 014 016 018MK weight fraction in total binder
0
005
01
015
02
Lim
esto
ne w
eigh
t fra
ctio
n in
tota
l bin
der
15 days
3 days
28 days and90 days
(e)
Figure 7 Analysis of optimum MK and LS combinations (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimum MK and LScombinations at different ages
Advances in Materials Science and Engineering 11
First a cement hydration model a metakaolin reactionmodel and a limestone reaction model are proposed in theternary-blended hydration model Pozzolanic reaction ofmetakaolin chemical and physics effect of limestone andsynergetic effect between metakaolin and limestone aredetailed considered in the ternary-blended hydration modelMoreover the interactions among cement hydrationlimestone reaction and metakaolin reaction are consideredthrough the contents of calcium hydroxide and capillarywater+e coefficients of the hydration model do not changefor various concrete mixtures
Second based on the hydration model the gel-spaceratio of hydrating blends is calculated considering thecontributions from the reactions of cement metakaolin andlimestone Furthermore the strength development of ter-nary blends is evaluated using the gel-space ratio +e co-efficients of the strength model do not change for variousconcrete mixtures Based on parameter analysis the syn-ergetic effect on strength development is shown and theoptimal combinations of cement-limestone-metakaolinternary blends are determined From the early age to lateage the optimum combinations of ternary blends shift fromhigh limestone-low metakaolin zone to low limestone-highmetakaolin zone
Data Availability
+e data used to support the findings of this study are in-cluded within the article
Conflicts of Interest
+e author declares that there are no conflicts of interestregarding the publication of this paper
Acknowledgments
+is research was supported by Basic Science ResearchProgram through the National Research Foundation ofKorea (NRF) funded by the Ministry of Science ICT andFuture Planning (no 2015R1A5A1037548) and a NRF grant(NRF-2017R1C1B1010076)
References
[1] X-Y Wang ldquoModeling of hydration compressive strengthand carbonation of Portland-limestone cement (PLC) con-creterdquo Materials vol 10 no 2 pp 115ndash131 2017
[2] X Y Wang and Y Luan ldquoModeling of hydration strengthdevelopment and optimum combinations of cement-slag-limestone ternary concreterdquo International Journal of Con-crete Structures and Materials vol 12 no 1 pp 193ndash2062018
[3] K Vance A Kumar G Sant and N Neithalath ldquo+e rhe-ological properties of ternary binders containing Portlandcement limestone and metakaolin or fly ashrdquo Cement andConcrete Research vol 52 pp 196ndash207 2013
[4] K Vance M Aguayo T Oey G Sant and N NeithalathldquoHydration and strength development in ternary portlandcement blends containing limestone and fly ash or
metakaolinrdquo Cement and Concrete Composites vol 39pp 93ndash103 2013
[5] G L Alvarez A Nazari A Bagheri J G Sanjayan andC De Lange ldquoMicrostructure electrical and mechanicalproperties of steel fibres reinforced cement mortars withpartial metakaolin and limestone additionrdquo Construction andBuilding Materials vol 135 pp 8ndash20 2017
[6] A M Ramezanianpour and R D Hooton ldquoA study on hy-dration compressive strength and porosity of Portland-limestone cement mixes containing SCMsrdquo Cement andConcrete Composites vol 51 pp 1ndash13 2014
[7] C Perlot P Rougeau and S Dehaudt ldquoSlurry of metakaolincombined with limestone addition for self-compacted con-crete application for precast industryrdquo Cement and ConcreteComposites vol 44 pp 50ndash57 2013
[8] K Sotiriadis E Nikolopoulou S Tsivilis A PavlouE Chaniotakis and R N Swamy ldquo+e effect of chlorides onthe thaumasite form of sulfate attack of limestone cementconcrete containing mineral admixtures at low temperaturerdquoConstruction and Building Materials vol 43 pp 156ndash1642013
[9] M Antoni J Rossen F Martirena and K Scrivener ldquoCementsubstitution by a combination of metakaolin and limestonerdquoCement and Concrete Research vol 42 no 12 pp 1579ndash15892012
[10] Z Shi M R Geiker K De Weerdt et al ldquoRole of calcium onchloride binding in hydrated Portland cement-metakaolin-limestone blendsrdquo Cement and Concrete Research vol 95pp 205ndash216 2017
[11] Z Shi B Lothenbach M R Geiker et al ldquoExperimentalstudies and thermodynamic modeling of the carbonation ofPortland cement metakaolin and limestonemortarsrdquo Cementand Concrete Research vol 88 pp 60ndash72 2016
[12] X-Y Wang and H-S Lee ldquoModeling the hydration ofconcrete incorporating fly ash or slagrdquo Cement and ConcreteResearch vol 40 no 7 pp 984ndash996 2010
[13] K Maekawa R Chaube and T Kishi Modelling of ConcretePerformance Hydration Microstructure and Mass TransportCRC Press London UK 1999
[14] K van Breugel Simulation of Hydration and Formation ofStructure in Hardening Cement-Based Materials Delft Uni-versity Press Delft Netherlands 1997
[15] X-Y Wang ldquoAnalysis of hydration-mechanical-durabilityproperties of metakaolin blended concreterdquo Applied Sci-ences vol 7 no 10 pp 1087ndash1102 2017
[16] V G Papadakis ldquoExperimental investigation and theoreticalmodeling of silica fume activity in concreterdquo Cement andConcrete Research vol 29 no 1 pp 79ndash86 1999
[17] Y Elakneswaran E Owaki S Miyahara M OginoT Maruya and T Nawa ldquoHydration study of slag-blendedcement based on thermodynamic considerationsrdquo Con-struction and Building Materials vol 124 pp 615ndash625 2016
[18] T Vuk V Tinta R Gabrovsek and V Kaucic ldquo+e effects oflimestone addition clinker type and fineness on properties ofPortland cementrdquo Cement and Concrete Research vol 31no 1 pp 135ndash139 2001
[19] V Bonavetti H Donza G Menendez O Cabrera andE F Irassar ldquoLimestone filler cement in low wc concrete arational use of energyrdquo Cement and Concrete Researchvol 33 no 6 pp 865ndash871 2003
[20] A M Dunster J R Parsonage and M J K +omas ldquo+epozzolanic reaction of metakaolinite and its effects onPortland cement hydrationrdquo Journal of Materials Sciencevol 28 no 5 pp 1345ndash1350 1993
12 Advances in Materials Science and Engineering
[21] D P Bentz ldquoModeling the influence of limestone filler oncement hydration using CEMHYD3Drdquo Cement and ConcreteComposites vol 28 no 2 pp 124ndash129 2006
[22] B Pichler C Hellmich J Eberhardsteiner et al ldquoEffect of gel-space ratio and microstructure on strength of hydrating ce-mentitious materials an engineering micromechanics ap-proachrdquo Cement and Concrete Research vol 45 pp 55ndash682013
[23] M Aqel and D K Panesar ldquoHydration kinetics and com-pressive strength of steam-cured cement pastes and mortarscontaining limestone fillerrdquo Construction and Building Ma-terials vol 113 pp 359ndash368 2016
[24] C-S Poon L Lam S C Kou Y-L Wong and R WongldquoRate of pozzolanic reaction of metakaolin in high-performance cement pastesrdquo Cement and Concrete Re-search vol 31 no 9 pp 1301ndash1306 2001
[25] L Lam Y L Wong and C S Poon ldquoDegree of hydration andgelspace ratio of high-volume fly ashcement systemsrdquo Ce-ment and Concrete Research vol 30 no 5 pp 747ndash756 2000
[26] D Damidot B Lothenbach D Herfort and F P Glasserldquo+ermodynamics and cement sciencerdquo Cement and ConcreteResearch vol 41 no 7 pp 679ndash695 2011
Advances in Materials Science and Engineering 13
CorrosionInternational Journal of
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ate
ria
ls
Hindawiwwwhindawicom Volume 2018
Journal ofNanomaterials
Submit your manuscripts atwwwhindawicom
Antoni et al [9] measured the reaction degrees of binder andcompressive strength of cement-MK-LS ternary-blendedconcrete +e chemical compositions of cement meta-kaolin and limestone are shown in Table 2 +e mixingproportions are shown in Table 3 Paste specimens with awater-to-binder ratio of 04 were used for measuring re-action degree of binders Mortar specimens with a water-to-binder ratio of 05 were used for measuring compressivestrength For cement-limestone binary blends the re-placement ratio of limestone was 15 while for cement-metakaolin binary blends the replacement ratio of meta-kaolin was 30 For ternary-blended specimens the sum oflimestone and metakaolin ranged from 15 to 60 and themass ratio of metakaolin to limestone was fixed as 2 +ereaction degrees and strength were measured at the ages of 17 28 and 90 days
+e input parameters of the ternary-blended cementhydration model are concrete mixtures curing temperatureand compound compositions and Blaine surface areas ofbinders By using the blended cement hydration model thereaction degree of MK and LS is calculated and shown inFigure 2
As shown in Figure 2(a) the sequences of the reactiondegree of MK from higher to lower are B15gtB30gtMK30gtB45gtB60 +is can be explained using the MK reactionmodel (equation (2)) As shown in equation (2) the reactiondegree of MKmainly depends on the mass ratio of cement to
MK As the ratio of cement to MK increases the activationeffect from cement hydration is enhanced and reactiondegree of MK increases +e mass ratios of cement to MKwere 85 35 233 183 and 1 in the mixtures of B15 B30MK30 B45 and B60 respectively +e orders of reactiondegree of MK are consistent with the mass ratios of cementto MK
As shown in Figure 2(b) the sequences of reactiondegree of limestone from higher to lower areB15 gt B30 gt B45 gt B60 +e proposed ternary-blendedhydration model can reflect this trend of reaction de-gree of LS In this study the mass ratio of MK to LS internary blends is constant and the difference of the re-action degree of LS is mainly due to the variations of thecement-to-limestone ratio +e mass ratios of cement toLS were 17 7 366 and 2 in the mixtures of B15 B30 B45and B60 respectively As the mass ratio of cement to LSdecreases the reaction degree of LS also decreases (pa-rameter m1 of equation (7)) +e trend of the reactiondegree of LS is consistent with the mass ratio of cement toLS In addition the reaction degree of LS at 1 day is almostzero +is also agrees with our analysis As shown inequation (6) we assumed that the reaction of LS startsafter 21 hours Furthermore the reactivity of LS is verylow At the age of 90 days the reaction degree of LS for B15is 12 which is much lower than cement
Figure 3 shows the parameter analysis of the hydrationmodel Figure 3(a) shows the reaction degree of LS incement-LS binary blends As limestone replacement ratioincreases the reaction degree of limestone decreases Similarto the contents shown in Figure 3(a) Aqel and Panesar [23]
Table 2 Chemical compositions of binders
Cement()
Limestone()
Metakaolin()
SiO2 2101 004 5062Al2O3 463 006 4691Fe2O3 260 005 038CaO 6418 5653 002MgO 182 010 009SO3 278 - 008Na2O 020 004 028K2O 094 004 018TiO2 014 003 129Others 044 002 016Loss on ignition(LOI) 126 4309 000
Total 1000 1000 1000
Table 3 Mixing proportions of specimens [9]
Cement () Limestone () Metakaolin ()PC 100 0 0LS15 85 15 0MK30 70 0 30B15 85 5 10B30 70 10 20B45 55 15 30B60 40 20 40
Setting of initial conditions and calculating time tend
t = t + Δt
t gt tendNo
End
Hydration model
Calculating a degree of hydration
Δα = fce(T t) ΔαMK = fMK(T t) ΔαLS = fLS(T t)
α = α + Δα αMK = αMK + ΔαMK αLS = αLS + ΔαLS
Amount of calcium hydroxideCH(t) = RCHCE lowast C0 lowast α ndash vMK lowast αMK lowast P
Amount of capillary water
Compressive strength
Wcap = W0 ndash 04 lowast C0 lowast α ndash 055 lowast αMK lowast P ndash 162 lowast LS0 lowast αLS
fc(t) = Axcn
Figure 1 Flowchart of simulation
Advances in Materials Science and Engineering 5
also found the reactivity of limestone will be lower with theincreasing of limestone content
Figure 3(b) shows the reaction degree of MK in cement-MK binary blends As MK replacement ratio increases theactivation effect from cement hydration becomes weakerand the reaction degree of MK decreases Similar to thecontents shown in Figure 3(b) Poon et al [24] also foundsimilar results that the reaction degree ofMKwill be lower asthe content of MK increases
Figure 3(c) shows the effect of MK additions on thereaction degree of LS +e addition of MK presents thetwofold effect on reaction of LS First when MK is added toreplace partial cement in the mixtures the mass ratio ofcement to LS decreases which will lower the reaction degreeof LS (this is considered through parameter m1 of equation(7)) However the aluminum content in MK (46) is aboutten times of the aluminum content in cement (46) +eaddition of MK will enhance the reaction of LS (this isconsidered through parameter m4 of equation (7)) Becausethe enhancing effect is much more significant than thelowering effect the addition of MK can increase the reactiondegree of limestone (shown in Figure 3(c)) Similar to thecontents shown in Figure 3(c) many researchers [4 9] alsoexperimentally found that reactivity of limestone can beimproved due to MK addition
Figure 3(d) shows the effect of metakaolin and limestonecontents on the reaction degree of cement When meta-kaolin and limestone are used to replace partial cement thereaction degree of cement is improved due to the dilutioneffect and nucleation effect (the dilution effect is consideredthrough parameter λ2 in equation (1) and the nucleationeffect is considered through equations (4) and (5)) Similarto the contents shown in Figure 3(d) Lam et al [25] alsofound that the addition of mineral admixtures can improvethe reaction degree of cement
32VerificationofStrengthDevelopmentModel By using thecement-MK-LS ternary-blended hydration model the gel-space ratio of hydrating concrete can be calculated (equation(10)) Furthermore based on the strength of concrete atdifferent ages the values of strength coefficients of a1 a2and a3 and b1 b2 and b3 can be calibrated (a1 140MPaa2 258MPa a3120MPa b1 385 b2113 andb3134) +ese coefficients do not vary with concretemixtures+e values of a1 and b1 relate to cement hydrationthe values of a2 and b2 relate to the metakaolin reaction andthe values of a3 and b3 relate to the limestone reaction Forcement-metakaolin binary blends the development ofstrength relates to a1 a2 b1 and b2 For cement-limestonebinary blends the development of strength relates to a1 a3b1 and b3 For cement-metakaolin-limestone ternaryblends the development of strength relates to a1 a2 a3 b1b2 and b3 +e analyzed results of compressive strength areshown in Figure 4 +e analysis results generally agree withexperimental results At the ages of 28 days the B15 concrete(cement 85+metakaolin 10+ limestone 5) has ahighest strength than other mixtures +is may be because ofthe synergetic effect of metakaolin and limestone
Because the strength coefficients of strength evaluationequation are constants for different concrete mixtures wecan make parameter analysis for different concrete mixturesFigure 5(a) shows the strength development of cement-limestone binary blends At the early age due to the nu-cleation effect the strength of limestone blends concreteshows higher strength than control concrete While at lateages due to the dilution effect the strength of limestoneblends concrete is lower than control concrete As thecontents of limestone increases from 10 to 20 the late-age strength decreases +e trend shown in Figure 5(a)agrees with Bonavetti et alrsquos [19] studies about strengthdevelopment of limestone-blended concrete
Time (hours)
08
06
04
02
0
Reac
tion
degr
ee o
f MK
100 102
MK30B15-MK10LS5B30-MK20LS10B45-MK30LS15B60-MK40LS20
Exper-MK30Exper-B15Exper-B30Exper-B45Exper-B60
(a)
100 102
Time (hours)
0
005
01
015
02
025
03
Reac
tion
degr
ee o
f lim
esto
ne p
owde
r
B15-MK10LS5B30-MK20LS10B45-MK30LS15B60-MK40LS20
Exper-B15Exper-B30Exper-B45Exper-B60
(b)
Figure 2 Verification of the hydration model (a) reaction degree of MK (b) reaction degree of LS
6 Advances in Materials Science and Engineering
Figure 5(b) shows the strength development of cement-metakaolin binary blends Metakaolin-blended concrete hasa higher strength than control concrete As the contents ofmetakaolin increases from 5 to 10 the strength alsoincreases +e trend shown in Figure 5(b) agrees with Poonet alrsquos [24] studies about strength development ofmetakaolin-blended concrete
Damidot et al [26] studies the strength development of70 cement + 30 clay-limestone ternary blends +e sumof clay and limestone was fixed as 30 and the weightfraction of clay(clay + limestone) ranges from 0 to 100[26] Damidot et al [26] found that at the age of 28 days themix with 70metakaolin has the highest strength than othermixes +is is because of the synergetic effect of limestoneand metakaolin [26] Based on the proposed strength de-velopment in this study we make parameter analysis of
strength development for 70 cement + 30 clay-limestoneternary blends In our analysis the sum of clay and limestoneis also fixed as 30 the weight fractions of clay(clay + limestone) are given as 0 25 50 75 and 100and the ages of parameter analysis are 15 days 3 days28 days and 90 days respectively +e results of parameteranalysis are shown in Figures 6(a)ndash6(d) As shown inFigure 6(a) at the age of 15 days the strength of blendedconcrete is higher than base Portland cement+is is becauseof the nucleation effect of limestone While as shown inFigures 6(b)ndash6(d) at the age of 3 days 28 days and 90 dayswhen the mk(mk + limestone) equals to zero (the content ofmetakaolin is zero and binder consists of 30 limestone and70 cement) the strength of limestone-blended concreteis lower than base Portland cement +is is because ofthe dilution effect of limestone While for other mk
0 500 1000 1500 2000 2500Time (hours)
0
001
002
003
004
005
006
007Re
actio
n de
gree
of l
imes
tone
Cement 95 + limestone 5Cement 90 + limestone 10Cement 85 + limestone 15
(a)
0 500 1000 1500 2000 2500Time (hours)
0
02
04
06
08
Reac
tion
degr
ee o
f MK
Cement 95 + MK5Cement 90 + MK10Cement 80 + MK20
(b)
0 500 1000 1500 2000 2500Time (hours)
0
001
002
003
004
005
006
007
Reac
tion
degr
ee o
f lim
esto
ne
Cement 55 + MK30 + LS15Cement 85 + MK0 + LS15
(c)
0 500 1000 1500 2000 2500Time (hours)
0
02
04
06
08
1Re
actio
n de
gree
of c
emen
t
ControlB60-MK40LS20
(d)
Figure 3 Parameter analysis of reaction degree of binders (a) effect of limestone contents on the reaction degree of limestone (b) effect ofmetakaolin contents on the reaction degree of metakaolin (c) effect of metakaolin contents on the reaction degree of limestone (d) effect ofmetakaolin and limestone contents on the reaction degree of cement
Advances in Materials Science and Engineering 7
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70C
ompr
essiv
e stre
ngth
(MPa
)
Analysis resultsExperimental results
Control
(a)
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
Analysis resultsExperimental results
(b)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
(c)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70C
ompr
essiv
e stre
ngth
(MPa
)MK 10 limestone 5
(d)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 20 limestone 10
(e)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 30 limestone 20
(f )
Figure 4 Continued
8 Advances in Materials Science and Engineering
(mk+ limestone) ratios of 25 50 75 and 100 be-cause the reaction of metakaolin can contribute to thestrength the strength of blended concrete is higher than basePortland cement
At the age of 15 days 3 days 28 days and 90 days theoptimum weight fractions of clay(clay + limestone) are 2550 75 and 75 respectively (shown in Figures 6(e)) Ouranalysis result about optimum weight fraction of clay(clay + limestone) is similar to that of Damidot et al [26]studies In addition our analysis shows that at the ages of15 days 3 days 28 days and 90 days the optimum weightfraction of limestone(clay + limestone) is 75 50 25 and25 respectively It means that at the early age limestone iseffective to improve the strength of concrete (this is because of
the nucleation effect of limestone) and at the late agemetakaolin is effective to improve the strength of concrete(this is because of the pozzolanic reaction of metakaolin)
In Figure 6 the sum of metakaolin and limestone isfixed as 30 To find the optimum combinations of ce-ment metakaolin and limestone we make much widerparameter analysis In this wider parameter analysis thesum of metakaolin and limestone is not a fixed value +econtents of metakaolin vary from 0 to 30 and thecontents of limestone vary from 0 to 20 +e analysisresults of isoline of strength are shown in Figures 7(a)ndash7(d) At the early age 15 days the concrete with a higherlimestone content and a lower metakaolin content hashighest strength (shown in Figure 7(a)) while at the late
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 40 limestone 20
(g)
Figure 4 Analysis of compressive strength (a) PC (b) LS15 (c) MK30 (d) B15 (e) B30 (f ) B45 (g) B60
10ndash2 100 102 104
Time (hours)
0
10
20
30
40
50
60
Com
pres
sive s
treng
th (M
Pa)
ControlLS10LS20
(a)
ControlMK5MK10
10ndash2 100 102 104
Time (hours)
0
20
40
60
80
Com
pres
sive s
treng
th (M
Pa)
(b)
Figure 5 Effect of LS and MK on strength development (a) cement-LS binary blends (b) cement-MK binary blends
Advances in Materials Science and Engineering 9
0 02 04 06 08 1MK(MK + limestone) weight fraction
19
195
20
205
21
215
221
5-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
Metakaolin + limestoneBase Portland cement
(a)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
25
26
27
28
29
30
3-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(b)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
35
40
45
50
55
60
28-d
ay co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(c)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
45
50
55
60
65
7090
-day
com
pres
sive s
treng
th (M
Pa)
70 PC + 30 (MK-limestone mix)
(d)
0 20 40 60 80 100Time (days)
02
03
04
05
06
07
08
Opt
imum
wei
ght f
ract
ion
in M
K +
limes
tone
ble
nds
70 PC + 30 (MK-limestone mix)
MK
(e)
Figure 6 Synergetic effect of cement-MK-LS ternary blends (MK+LS 30) (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimumfractions of MK
10 Advances in Materials Science and Engineering
age of 90 days the concrete with a higher metakaolincontent and a lower limestone content has higheststrength (shown in Figure 7(d)) In other words toachieve the highest strength of cement-metakaolin-limestone ternary blends the optimum combination ofmetakaolin and limestone is dependent on ages From theearly age to late age the optimum combinations change
shift from high limestone-low metakaolin zone to lowlimestone-high metakaolin zone (shown in Figure 7(e))
4 Conclusions
+is study presents an integrated hydration-strength modelfor cement-limestone-metakaolin ternary blends
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03M
K w
eigh
t fra
ctio
n in
tota
l bin
der
195
20
205
21
215
(a)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
265
27
275
28
285
29
295
(b)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
44
46
48
50
52
54
56
(c)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
52
54
56
58
60
62
64
66
68
(d)
008 01 012 014 016 018MK weight fraction in total binder
0
005
01
015
02
Lim
esto
ne w
eigh
t fra
ctio
n in
tota
l bin
der
15 days
3 days
28 days and90 days
(e)
Figure 7 Analysis of optimum MK and LS combinations (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimum MK and LScombinations at different ages
Advances in Materials Science and Engineering 11
First a cement hydration model a metakaolin reactionmodel and a limestone reaction model are proposed in theternary-blended hydration model Pozzolanic reaction ofmetakaolin chemical and physics effect of limestone andsynergetic effect between metakaolin and limestone aredetailed considered in the ternary-blended hydration modelMoreover the interactions among cement hydrationlimestone reaction and metakaolin reaction are consideredthrough the contents of calcium hydroxide and capillarywater+e coefficients of the hydration model do not changefor various concrete mixtures
Second based on the hydration model the gel-spaceratio of hydrating blends is calculated considering thecontributions from the reactions of cement metakaolin andlimestone Furthermore the strength development of ter-nary blends is evaluated using the gel-space ratio +e co-efficients of the strength model do not change for variousconcrete mixtures Based on parameter analysis the syn-ergetic effect on strength development is shown and theoptimal combinations of cement-limestone-metakaolinternary blends are determined From the early age to lateage the optimum combinations of ternary blends shift fromhigh limestone-low metakaolin zone to low limestone-highmetakaolin zone
Data Availability
+e data used to support the findings of this study are in-cluded within the article
Conflicts of Interest
+e author declares that there are no conflicts of interestregarding the publication of this paper
Acknowledgments
+is research was supported by Basic Science ResearchProgram through the National Research Foundation ofKorea (NRF) funded by the Ministry of Science ICT andFuture Planning (no 2015R1A5A1037548) and a NRF grant(NRF-2017R1C1B1010076)
References
[1] X-Y Wang ldquoModeling of hydration compressive strengthand carbonation of Portland-limestone cement (PLC) con-creterdquo Materials vol 10 no 2 pp 115ndash131 2017
[2] X Y Wang and Y Luan ldquoModeling of hydration strengthdevelopment and optimum combinations of cement-slag-limestone ternary concreterdquo International Journal of Con-crete Structures and Materials vol 12 no 1 pp 193ndash2062018
[3] K Vance A Kumar G Sant and N Neithalath ldquo+e rhe-ological properties of ternary binders containing Portlandcement limestone and metakaolin or fly ashrdquo Cement andConcrete Research vol 52 pp 196ndash207 2013
[4] K Vance M Aguayo T Oey G Sant and N NeithalathldquoHydration and strength development in ternary portlandcement blends containing limestone and fly ash or
metakaolinrdquo Cement and Concrete Composites vol 39pp 93ndash103 2013
[5] G L Alvarez A Nazari A Bagheri J G Sanjayan andC De Lange ldquoMicrostructure electrical and mechanicalproperties of steel fibres reinforced cement mortars withpartial metakaolin and limestone additionrdquo Construction andBuilding Materials vol 135 pp 8ndash20 2017
[6] A M Ramezanianpour and R D Hooton ldquoA study on hy-dration compressive strength and porosity of Portland-limestone cement mixes containing SCMsrdquo Cement andConcrete Composites vol 51 pp 1ndash13 2014
[7] C Perlot P Rougeau and S Dehaudt ldquoSlurry of metakaolincombined with limestone addition for self-compacted con-crete application for precast industryrdquo Cement and ConcreteComposites vol 44 pp 50ndash57 2013
[8] K Sotiriadis E Nikolopoulou S Tsivilis A PavlouE Chaniotakis and R N Swamy ldquo+e effect of chlorides onthe thaumasite form of sulfate attack of limestone cementconcrete containing mineral admixtures at low temperaturerdquoConstruction and Building Materials vol 43 pp 156ndash1642013
[9] M Antoni J Rossen F Martirena and K Scrivener ldquoCementsubstitution by a combination of metakaolin and limestonerdquoCement and Concrete Research vol 42 no 12 pp 1579ndash15892012
[10] Z Shi M R Geiker K De Weerdt et al ldquoRole of calcium onchloride binding in hydrated Portland cement-metakaolin-limestone blendsrdquo Cement and Concrete Research vol 95pp 205ndash216 2017
[11] Z Shi B Lothenbach M R Geiker et al ldquoExperimentalstudies and thermodynamic modeling of the carbonation ofPortland cement metakaolin and limestonemortarsrdquo Cementand Concrete Research vol 88 pp 60ndash72 2016
[12] X-Y Wang and H-S Lee ldquoModeling the hydration ofconcrete incorporating fly ash or slagrdquo Cement and ConcreteResearch vol 40 no 7 pp 984ndash996 2010
[13] K Maekawa R Chaube and T Kishi Modelling of ConcretePerformance Hydration Microstructure and Mass TransportCRC Press London UK 1999
[14] K van Breugel Simulation of Hydration and Formation ofStructure in Hardening Cement-Based Materials Delft Uni-versity Press Delft Netherlands 1997
[15] X-Y Wang ldquoAnalysis of hydration-mechanical-durabilityproperties of metakaolin blended concreterdquo Applied Sci-ences vol 7 no 10 pp 1087ndash1102 2017
[16] V G Papadakis ldquoExperimental investigation and theoreticalmodeling of silica fume activity in concreterdquo Cement andConcrete Research vol 29 no 1 pp 79ndash86 1999
[17] Y Elakneswaran E Owaki S Miyahara M OginoT Maruya and T Nawa ldquoHydration study of slag-blendedcement based on thermodynamic considerationsrdquo Con-struction and Building Materials vol 124 pp 615ndash625 2016
[18] T Vuk V Tinta R Gabrovsek and V Kaucic ldquo+e effects oflimestone addition clinker type and fineness on properties ofPortland cementrdquo Cement and Concrete Research vol 31no 1 pp 135ndash139 2001
[19] V Bonavetti H Donza G Menendez O Cabrera andE F Irassar ldquoLimestone filler cement in low wc concrete arational use of energyrdquo Cement and Concrete Researchvol 33 no 6 pp 865ndash871 2003
[20] A M Dunster J R Parsonage and M J K +omas ldquo+epozzolanic reaction of metakaolinite and its effects onPortland cement hydrationrdquo Journal of Materials Sciencevol 28 no 5 pp 1345ndash1350 1993
12 Advances in Materials Science and Engineering
[21] D P Bentz ldquoModeling the influence of limestone filler oncement hydration using CEMHYD3Drdquo Cement and ConcreteComposites vol 28 no 2 pp 124ndash129 2006
[22] B Pichler C Hellmich J Eberhardsteiner et al ldquoEffect of gel-space ratio and microstructure on strength of hydrating ce-mentitious materials an engineering micromechanics ap-proachrdquo Cement and Concrete Research vol 45 pp 55ndash682013
[23] M Aqel and D K Panesar ldquoHydration kinetics and com-pressive strength of steam-cured cement pastes and mortarscontaining limestone fillerrdquo Construction and Building Ma-terials vol 113 pp 359ndash368 2016
[24] C-S Poon L Lam S C Kou Y-L Wong and R WongldquoRate of pozzolanic reaction of metakaolin in high-performance cement pastesrdquo Cement and Concrete Re-search vol 31 no 9 pp 1301ndash1306 2001
[25] L Lam Y L Wong and C S Poon ldquoDegree of hydration andgelspace ratio of high-volume fly ashcement systemsrdquo Ce-ment and Concrete Research vol 30 no 5 pp 747ndash756 2000
[26] D Damidot B Lothenbach D Herfort and F P Glasserldquo+ermodynamics and cement sciencerdquo Cement and ConcreteResearch vol 41 no 7 pp 679ndash695 2011
Advances in Materials Science and Engineering 13
CorrosionInternational Journal of
Hindawiwwwhindawicom Volume 2018
Advances in
Materials Science and EngineeringHindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Journal of
Chemistry
Analytical ChemistryInternational Journal of
Hindawiwwwhindawicom Volume 2018
ScienticaHindawiwwwhindawicom Volume 2018
Polymer ScienceInternational Journal of
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Advances in Condensed Matter Physics
Hindawiwwwhindawicom Volume 2018
International Journal of
BiomaterialsHindawiwwwhindawicom
Journal ofEngineeringVolume 2018
Applied ChemistryJournal of
Hindawiwwwhindawicom Volume 2018
NanotechnologyHindawiwwwhindawicom Volume 2018
Journal of
Hindawiwwwhindawicom Volume 2018
High Energy PhysicsAdvances in
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The Scientific World Journal
Volume 2018
TribologyAdvances in
Hindawiwwwhindawicom Volume 2018
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Hindawiwwwhindawicom Volume 2018
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Hindawiwwwhindawicom Volume 2018
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ate
ria
ls
Hindawiwwwhindawicom Volume 2018
Journal ofNanomaterials
Submit your manuscripts atwwwhindawicom
also found the reactivity of limestone will be lower with theincreasing of limestone content
Figure 3(b) shows the reaction degree of MK in cement-MK binary blends As MK replacement ratio increases theactivation effect from cement hydration becomes weakerand the reaction degree of MK decreases Similar to thecontents shown in Figure 3(b) Poon et al [24] also foundsimilar results that the reaction degree ofMKwill be lower asthe content of MK increases
Figure 3(c) shows the effect of MK additions on thereaction degree of LS +e addition of MK presents thetwofold effect on reaction of LS First when MK is added toreplace partial cement in the mixtures the mass ratio ofcement to LS decreases which will lower the reaction degreeof LS (this is considered through parameter m1 of equation(7)) However the aluminum content in MK (46) is aboutten times of the aluminum content in cement (46) +eaddition of MK will enhance the reaction of LS (this isconsidered through parameter m4 of equation (7)) Becausethe enhancing effect is much more significant than thelowering effect the addition of MK can increase the reactiondegree of limestone (shown in Figure 3(c)) Similar to thecontents shown in Figure 3(c) many researchers [4 9] alsoexperimentally found that reactivity of limestone can beimproved due to MK addition
Figure 3(d) shows the effect of metakaolin and limestonecontents on the reaction degree of cement When meta-kaolin and limestone are used to replace partial cement thereaction degree of cement is improved due to the dilutioneffect and nucleation effect (the dilution effect is consideredthrough parameter λ2 in equation (1) and the nucleationeffect is considered through equations (4) and (5)) Similarto the contents shown in Figure 3(d) Lam et al [25] alsofound that the addition of mineral admixtures can improvethe reaction degree of cement
32VerificationofStrengthDevelopmentModel By using thecement-MK-LS ternary-blended hydration model the gel-space ratio of hydrating concrete can be calculated (equation(10)) Furthermore based on the strength of concrete atdifferent ages the values of strength coefficients of a1 a2and a3 and b1 b2 and b3 can be calibrated (a1 140MPaa2 258MPa a3120MPa b1 385 b2113 andb3134) +ese coefficients do not vary with concretemixtures+e values of a1 and b1 relate to cement hydrationthe values of a2 and b2 relate to the metakaolin reaction andthe values of a3 and b3 relate to the limestone reaction Forcement-metakaolin binary blends the development ofstrength relates to a1 a2 b1 and b2 For cement-limestonebinary blends the development of strength relates to a1 a3b1 and b3 For cement-metakaolin-limestone ternaryblends the development of strength relates to a1 a2 a3 b1b2 and b3 +e analyzed results of compressive strength areshown in Figure 4 +e analysis results generally agree withexperimental results At the ages of 28 days the B15 concrete(cement 85+metakaolin 10+ limestone 5) has ahighest strength than other mixtures +is may be because ofthe synergetic effect of metakaolin and limestone
Because the strength coefficients of strength evaluationequation are constants for different concrete mixtures wecan make parameter analysis for different concrete mixturesFigure 5(a) shows the strength development of cement-limestone binary blends At the early age due to the nu-cleation effect the strength of limestone blends concreteshows higher strength than control concrete While at lateages due to the dilution effect the strength of limestoneblends concrete is lower than control concrete As thecontents of limestone increases from 10 to 20 the late-age strength decreases +e trend shown in Figure 5(a)agrees with Bonavetti et alrsquos [19] studies about strengthdevelopment of limestone-blended concrete
Time (hours)
08
06
04
02
0
Reac
tion
degr
ee o
f MK
100 102
MK30B15-MK10LS5B30-MK20LS10B45-MK30LS15B60-MK40LS20
Exper-MK30Exper-B15Exper-B30Exper-B45Exper-B60
(a)
100 102
Time (hours)
0
005
01
015
02
025
03
Reac
tion
degr
ee o
f lim
esto
ne p
owde
r
B15-MK10LS5B30-MK20LS10B45-MK30LS15B60-MK40LS20
Exper-B15Exper-B30Exper-B45Exper-B60
(b)
Figure 2 Verification of the hydration model (a) reaction degree of MK (b) reaction degree of LS
6 Advances in Materials Science and Engineering
Figure 5(b) shows the strength development of cement-metakaolin binary blends Metakaolin-blended concrete hasa higher strength than control concrete As the contents ofmetakaolin increases from 5 to 10 the strength alsoincreases +e trend shown in Figure 5(b) agrees with Poonet alrsquos [24] studies about strength development ofmetakaolin-blended concrete
Damidot et al [26] studies the strength development of70 cement + 30 clay-limestone ternary blends +e sumof clay and limestone was fixed as 30 and the weightfraction of clay(clay + limestone) ranges from 0 to 100[26] Damidot et al [26] found that at the age of 28 days themix with 70metakaolin has the highest strength than othermixes +is is because of the synergetic effect of limestoneand metakaolin [26] Based on the proposed strength de-velopment in this study we make parameter analysis of
strength development for 70 cement + 30 clay-limestoneternary blends In our analysis the sum of clay and limestoneis also fixed as 30 the weight fractions of clay(clay + limestone) are given as 0 25 50 75 and 100and the ages of parameter analysis are 15 days 3 days28 days and 90 days respectively +e results of parameteranalysis are shown in Figures 6(a)ndash6(d) As shown inFigure 6(a) at the age of 15 days the strength of blendedconcrete is higher than base Portland cement+is is becauseof the nucleation effect of limestone While as shown inFigures 6(b)ndash6(d) at the age of 3 days 28 days and 90 dayswhen the mk(mk + limestone) equals to zero (the content ofmetakaolin is zero and binder consists of 30 limestone and70 cement) the strength of limestone-blended concreteis lower than base Portland cement +is is because ofthe dilution effect of limestone While for other mk
0 500 1000 1500 2000 2500Time (hours)
0
001
002
003
004
005
006
007Re
actio
n de
gree
of l
imes
tone
Cement 95 + limestone 5Cement 90 + limestone 10Cement 85 + limestone 15
(a)
0 500 1000 1500 2000 2500Time (hours)
0
02
04
06
08
Reac
tion
degr
ee o
f MK
Cement 95 + MK5Cement 90 + MK10Cement 80 + MK20
(b)
0 500 1000 1500 2000 2500Time (hours)
0
001
002
003
004
005
006
007
Reac
tion
degr
ee o
f lim
esto
ne
Cement 55 + MK30 + LS15Cement 85 + MK0 + LS15
(c)
0 500 1000 1500 2000 2500Time (hours)
0
02
04
06
08
1Re
actio
n de
gree
of c
emen
t
ControlB60-MK40LS20
(d)
Figure 3 Parameter analysis of reaction degree of binders (a) effect of limestone contents on the reaction degree of limestone (b) effect ofmetakaolin contents on the reaction degree of metakaolin (c) effect of metakaolin contents on the reaction degree of limestone (d) effect ofmetakaolin and limestone contents on the reaction degree of cement
Advances in Materials Science and Engineering 7
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70C
ompr
essiv
e stre
ngth
(MPa
)
Analysis resultsExperimental results
Control
(a)
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
Analysis resultsExperimental results
(b)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
(c)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70C
ompr
essiv
e stre
ngth
(MPa
)MK 10 limestone 5
(d)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 20 limestone 10
(e)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 30 limestone 20
(f )
Figure 4 Continued
8 Advances in Materials Science and Engineering
(mk+ limestone) ratios of 25 50 75 and 100 be-cause the reaction of metakaolin can contribute to thestrength the strength of blended concrete is higher than basePortland cement
At the age of 15 days 3 days 28 days and 90 days theoptimum weight fractions of clay(clay + limestone) are 2550 75 and 75 respectively (shown in Figures 6(e)) Ouranalysis result about optimum weight fraction of clay(clay + limestone) is similar to that of Damidot et al [26]studies In addition our analysis shows that at the ages of15 days 3 days 28 days and 90 days the optimum weightfraction of limestone(clay + limestone) is 75 50 25 and25 respectively It means that at the early age limestone iseffective to improve the strength of concrete (this is because of
the nucleation effect of limestone) and at the late agemetakaolin is effective to improve the strength of concrete(this is because of the pozzolanic reaction of metakaolin)
In Figure 6 the sum of metakaolin and limestone isfixed as 30 To find the optimum combinations of ce-ment metakaolin and limestone we make much widerparameter analysis In this wider parameter analysis thesum of metakaolin and limestone is not a fixed value +econtents of metakaolin vary from 0 to 30 and thecontents of limestone vary from 0 to 20 +e analysisresults of isoline of strength are shown in Figures 7(a)ndash7(d) At the early age 15 days the concrete with a higherlimestone content and a lower metakaolin content hashighest strength (shown in Figure 7(a)) while at the late
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 40 limestone 20
(g)
Figure 4 Analysis of compressive strength (a) PC (b) LS15 (c) MK30 (d) B15 (e) B30 (f ) B45 (g) B60
10ndash2 100 102 104
Time (hours)
0
10
20
30
40
50
60
Com
pres
sive s
treng
th (M
Pa)
ControlLS10LS20
(a)
ControlMK5MK10
10ndash2 100 102 104
Time (hours)
0
20
40
60
80
Com
pres
sive s
treng
th (M
Pa)
(b)
Figure 5 Effect of LS and MK on strength development (a) cement-LS binary blends (b) cement-MK binary blends
Advances in Materials Science and Engineering 9
0 02 04 06 08 1MK(MK + limestone) weight fraction
19
195
20
205
21
215
221
5-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
Metakaolin + limestoneBase Portland cement
(a)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
25
26
27
28
29
30
3-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(b)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
35
40
45
50
55
60
28-d
ay co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(c)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
45
50
55
60
65
7090
-day
com
pres
sive s
treng
th (M
Pa)
70 PC + 30 (MK-limestone mix)
(d)
0 20 40 60 80 100Time (days)
02
03
04
05
06
07
08
Opt
imum
wei
ght f
ract
ion
in M
K +
limes
tone
ble
nds
70 PC + 30 (MK-limestone mix)
MK
(e)
Figure 6 Synergetic effect of cement-MK-LS ternary blends (MK+LS 30) (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimumfractions of MK
10 Advances in Materials Science and Engineering
age of 90 days the concrete with a higher metakaolincontent and a lower limestone content has higheststrength (shown in Figure 7(d)) In other words toachieve the highest strength of cement-metakaolin-limestone ternary blends the optimum combination ofmetakaolin and limestone is dependent on ages From theearly age to late age the optimum combinations change
shift from high limestone-low metakaolin zone to lowlimestone-high metakaolin zone (shown in Figure 7(e))
4 Conclusions
+is study presents an integrated hydration-strength modelfor cement-limestone-metakaolin ternary blends
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03M
K w
eigh
t fra
ctio
n in
tota
l bin
der
195
20
205
21
215
(a)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
265
27
275
28
285
29
295
(b)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
44
46
48
50
52
54
56
(c)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
52
54
56
58
60
62
64
66
68
(d)
008 01 012 014 016 018MK weight fraction in total binder
0
005
01
015
02
Lim
esto
ne w
eigh
t fra
ctio
n in
tota
l bin
der
15 days
3 days
28 days and90 days
(e)
Figure 7 Analysis of optimum MK and LS combinations (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimum MK and LScombinations at different ages
Advances in Materials Science and Engineering 11
First a cement hydration model a metakaolin reactionmodel and a limestone reaction model are proposed in theternary-blended hydration model Pozzolanic reaction ofmetakaolin chemical and physics effect of limestone andsynergetic effect between metakaolin and limestone aredetailed considered in the ternary-blended hydration modelMoreover the interactions among cement hydrationlimestone reaction and metakaolin reaction are consideredthrough the contents of calcium hydroxide and capillarywater+e coefficients of the hydration model do not changefor various concrete mixtures
Second based on the hydration model the gel-spaceratio of hydrating blends is calculated considering thecontributions from the reactions of cement metakaolin andlimestone Furthermore the strength development of ter-nary blends is evaluated using the gel-space ratio +e co-efficients of the strength model do not change for variousconcrete mixtures Based on parameter analysis the syn-ergetic effect on strength development is shown and theoptimal combinations of cement-limestone-metakaolinternary blends are determined From the early age to lateage the optimum combinations of ternary blends shift fromhigh limestone-low metakaolin zone to low limestone-highmetakaolin zone
Data Availability
+e data used to support the findings of this study are in-cluded within the article
Conflicts of Interest
+e author declares that there are no conflicts of interestregarding the publication of this paper
Acknowledgments
+is research was supported by Basic Science ResearchProgram through the National Research Foundation ofKorea (NRF) funded by the Ministry of Science ICT andFuture Planning (no 2015R1A5A1037548) and a NRF grant(NRF-2017R1C1B1010076)
References
[1] X-Y Wang ldquoModeling of hydration compressive strengthand carbonation of Portland-limestone cement (PLC) con-creterdquo Materials vol 10 no 2 pp 115ndash131 2017
[2] X Y Wang and Y Luan ldquoModeling of hydration strengthdevelopment and optimum combinations of cement-slag-limestone ternary concreterdquo International Journal of Con-crete Structures and Materials vol 12 no 1 pp 193ndash2062018
[3] K Vance A Kumar G Sant and N Neithalath ldquo+e rhe-ological properties of ternary binders containing Portlandcement limestone and metakaolin or fly ashrdquo Cement andConcrete Research vol 52 pp 196ndash207 2013
[4] K Vance M Aguayo T Oey G Sant and N NeithalathldquoHydration and strength development in ternary portlandcement blends containing limestone and fly ash or
metakaolinrdquo Cement and Concrete Composites vol 39pp 93ndash103 2013
[5] G L Alvarez A Nazari A Bagheri J G Sanjayan andC De Lange ldquoMicrostructure electrical and mechanicalproperties of steel fibres reinforced cement mortars withpartial metakaolin and limestone additionrdquo Construction andBuilding Materials vol 135 pp 8ndash20 2017
[6] A M Ramezanianpour and R D Hooton ldquoA study on hy-dration compressive strength and porosity of Portland-limestone cement mixes containing SCMsrdquo Cement andConcrete Composites vol 51 pp 1ndash13 2014
[7] C Perlot P Rougeau and S Dehaudt ldquoSlurry of metakaolincombined with limestone addition for self-compacted con-crete application for precast industryrdquo Cement and ConcreteComposites vol 44 pp 50ndash57 2013
[8] K Sotiriadis E Nikolopoulou S Tsivilis A PavlouE Chaniotakis and R N Swamy ldquo+e effect of chlorides onthe thaumasite form of sulfate attack of limestone cementconcrete containing mineral admixtures at low temperaturerdquoConstruction and Building Materials vol 43 pp 156ndash1642013
[9] M Antoni J Rossen F Martirena and K Scrivener ldquoCementsubstitution by a combination of metakaolin and limestonerdquoCement and Concrete Research vol 42 no 12 pp 1579ndash15892012
[10] Z Shi M R Geiker K De Weerdt et al ldquoRole of calcium onchloride binding in hydrated Portland cement-metakaolin-limestone blendsrdquo Cement and Concrete Research vol 95pp 205ndash216 2017
[11] Z Shi B Lothenbach M R Geiker et al ldquoExperimentalstudies and thermodynamic modeling of the carbonation ofPortland cement metakaolin and limestonemortarsrdquo Cementand Concrete Research vol 88 pp 60ndash72 2016
[12] X-Y Wang and H-S Lee ldquoModeling the hydration ofconcrete incorporating fly ash or slagrdquo Cement and ConcreteResearch vol 40 no 7 pp 984ndash996 2010
[13] K Maekawa R Chaube and T Kishi Modelling of ConcretePerformance Hydration Microstructure and Mass TransportCRC Press London UK 1999
[14] K van Breugel Simulation of Hydration and Formation ofStructure in Hardening Cement-Based Materials Delft Uni-versity Press Delft Netherlands 1997
[15] X-Y Wang ldquoAnalysis of hydration-mechanical-durabilityproperties of metakaolin blended concreterdquo Applied Sci-ences vol 7 no 10 pp 1087ndash1102 2017
[16] V G Papadakis ldquoExperimental investigation and theoreticalmodeling of silica fume activity in concreterdquo Cement andConcrete Research vol 29 no 1 pp 79ndash86 1999
[17] Y Elakneswaran E Owaki S Miyahara M OginoT Maruya and T Nawa ldquoHydration study of slag-blendedcement based on thermodynamic considerationsrdquo Con-struction and Building Materials vol 124 pp 615ndash625 2016
[18] T Vuk V Tinta R Gabrovsek and V Kaucic ldquo+e effects oflimestone addition clinker type and fineness on properties ofPortland cementrdquo Cement and Concrete Research vol 31no 1 pp 135ndash139 2001
[19] V Bonavetti H Donza G Menendez O Cabrera andE F Irassar ldquoLimestone filler cement in low wc concrete arational use of energyrdquo Cement and Concrete Researchvol 33 no 6 pp 865ndash871 2003
[20] A M Dunster J R Parsonage and M J K +omas ldquo+epozzolanic reaction of metakaolinite and its effects onPortland cement hydrationrdquo Journal of Materials Sciencevol 28 no 5 pp 1345ndash1350 1993
12 Advances in Materials Science and Engineering
[21] D P Bentz ldquoModeling the influence of limestone filler oncement hydration using CEMHYD3Drdquo Cement and ConcreteComposites vol 28 no 2 pp 124ndash129 2006
[22] B Pichler C Hellmich J Eberhardsteiner et al ldquoEffect of gel-space ratio and microstructure on strength of hydrating ce-mentitious materials an engineering micromechanics ap-proachrdquo Cement and Concrete Research vol 45 pp 55ndash682013
[23] M Aqel and D K Panesar ldquoHydration kinetics and com-pressive strength of steam-cured cement pastes and mortarscontaining limestone fillerrdquo Construction and Building Ma-terials vol 113 pp 359ndash368 2016
[24] C-S Poon L Lam S C Kou Y-L Wong and R WongldquoRate of pozzolanic reaction of metakaolin in high-performance cement pastesrdquo Cement and Concrete Re-search vol 31 no 9 pp 1301ndash1306 2001
[25] L Lam Y L Wong and C S Poon ldquoDegree of hydration andgelspace ratio of high-volume fly ashcement systemsrdquo Ce-ment and Concrete Research vol 30 no 5 pp 747ndash756 2000
[26] D Damidot B Lothenbach D Herfort and F P Glasserldquo+ermodynamics and cement sciencerdquo Cement and ConcreteResearch vol 41 no 7 pp 679ndash695 2011
Advances in Materials Science and Engineering 13
CorrosionInternational Journal of
Hindawiwwwhindawicom Volume 2018
Advances in
Materials Science and EngineeringHindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Journal of
Chemistry
Analytical ChemistryInternational Journal of
Hindawiwwwhindawicom Volume 2018
ScienticaHindawiwwwhindawicom Volume 2018
Polymer ScienceInternational Journal of
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Advances in Condensed Matter Physics
Hindawiwwwhindawicom Volume 2018
International Journal of
BiomaterialsHindawiwwwhindawicom
Journal ofEngineeringVolume 2018
Applied ChemistryJournal of
Hindawiwwwhindawicom Volume 2018
NanotechnologyHindawiwwwhindawicom Volume 2018
Journal of
Hindawiwwwhindawicom Volume 2018
High Energy PhysicsAdvances in
Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom
The Scientific World Journal
Volume 2018
TribologyAdvances in
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
ChemistryAdvances in
Hindawiwwwhindawicom Volume 2018
Advances inPhysical Chemistry
Hindawiwwwhindawicom Volume 2018
BioMed Research InternationalMaterials
Journal of
Hindawiwwwhindawicom Volume 2018
Na
nom
ate
ria
ls
Hindawiwwwhindawicom Volume 2018
Journal ofNanomaterials
Submit your manuscripts atwwwhindawicom
Figure 5(b) shows the strength development of cement-metakaolin binary blends Metakaolin-blended concrete hasa higher strength than control concrete As the contents ofmetakaolin increases from 5 to 10 the strength alsoincreases +e trend shown in Figure 5(b) agrees with Poonet alrsquos [24] studies about strength development ofmetakaolin-blended concrete
Damidot et al [26] studies the strength development of70 cement + 30 clay-limestone ternary blends +e sumof clay and limestone was fixed as 30 and the weightfraction of clay(clay + limestone) ranges from 0 to 100[26] Damidot et al [26] found that at the age of 28 days themix with 70metakaolin has the highest strength than othermixes +is is because of the synergetic effect of limestoneand metakaolin [26] Based on the proposed strength de-velopment in this study we make parameter analysis of
strength development for 70 cement + 30 clay-limestoneternary blends In our analysis the sum of clay and limestoneis also fixed as 30 the weight fractions of clay(clay + limestone) are given as 0 25 50 75 and 100and the ages of parameter analysis are 15 days 3 days28 days and 90 days respectively +e results of parameteranalysis are shown in Figures 6(a)ndash6(d) As shown inFigure 6(a) at the age of 15 days the strength of blendedconcrete is higher than base Portland cement+is is becauseof the nucleation effect of limestone While as shown inFigures 6(b)ndash6(d) at the age of 3 days 28 days and 90 dayswhen the mk(mk + limestone) equals to zero (the content ofmetakaolin is zero and binder consists of 30 limestone and70 cement) the strength of limestone-blended concreteis lower than base Portland cement +is is because ofthe dilution effect of limestone While for other mk
0 500 1000 1500 2000 2500Time (hours)
0
001
002
003
004
005
006
007Re
actio
n de
gree
of l
imes
tone
Cement 95 + limestone 5Cement 90 + limestone 10Cement 85 + limestone 15
(a)
0 500 1000 1500 2000 2500Time (hours)
0
02
04
06
08
Reac
tion
degr
ee o
f MK
Cement 95 + MK5Cement 90 + MK10Cement 80 + MK20
(b)
0 500 1000 1500 2000 2500Time (hours)
0
001
002
003
004
005
006
007
Reac
tion
degr
ee o
f lim
esto
ne
Cement 55 + MK30 + LS15Cement 85 + MK0 + LS15
(c)
0 500 1000 1500 2000 2500Time (hours)
0
02
04
06
08
1Re
actio
n de
gree
of c
emen
t
ControlB60-MK40LS20
(d)
Figure 3 Parameter analysis of reaction degree of binders (a) effect of limestone contents on the reaction degree of limestone (b) effect ofmetakaolin contents on the reaction degree of metakaolin (c) effect of metakaolin contents on the reaction degree of limestone (d) effect ofmetakaolin and limestone contents on the reaction degree of cement
Advances in Materials Science and Engineering 7
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70C
ompr
essiv
e stre
ngth
(MPa
)
Analysis resultsExperimental results
Control
(a)
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
Analysis resultsExperimental results
(b)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
(c)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70C
ompr
essiv
e stre
ngth
(MPa
)MK 10 limestone 5
(d)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 20 limestone 10
(e)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 30 limestone 20
(f )
Figure 4 Continued
8 Advances in Materials Science and Engineering
(mk+ limestone) ratios of 25 50 75 and 100 be-cause the reaction of metakaolin can contribute to thestrength the strength of blended concrete is higher than basePortland cement
At the age of 15 days 3 days 28 days and 90 days theoptimum weight fractions of clay(clay + limestone) are 2550 75 and 75 respectively (shown in Figures 6(e)) Ouranalysis result about optimum weight fraction of clay(clay + limestone) is similar to that of Damidot et al [26]studies In addition our analysis shows that at the ages of15 days 3 days 28 days and 90 days the optimum weightfraction of limestone(clay + limestone) is 75 50 25 and25 respectively It means that at the early age limestone iseffective to improve the strength of concrete (this is because of
the nucleation effect of limestone) and at the late agemetakaolin is effective to improve the strength of concrete(this is because of the pozzolanic reaction of metakaolin)
In Figure 6 the sum of metakaolin and limestone isfixed as 30 To find the optimum combinations of ce-ment metakaolin and limestone we make much widerparameter analysis In this wider parameter analysis thesum of metakaolin and limestone is not a fixed value +econtents of metakaolin vary from 0 to 30 and thecontents of limestone vary from 0 to 20 +e analysisresults of isoline of strength are shown in Figures 7(a)ndash7(d) At the early age 15 days the concrete with a higherlimestone content and a lower metakaolin content hashighest strength (shown in Figure 7(a)) while at the late
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 40 limestone 20
(g)
Figure 4 Analysis of compressive strength (a) PC (b) LS15 (c) MK30 (d) B15 (e) B30 (f ) B45 (g) B60
10ndash2 100 102 104
Time (hours)
0
10
20
30
40
50
60
Com
pres
sive s
treng
th (M
Pa)
ControlLS10LS20
(a)
ControlMK5MK10
10ndash2 100 102 104
Time (hours)
0
20
40
60
80
Com
pres
sive s
treng
th (M
Pa)
(b)
Figure 5 Effect of LS and MK on strength development (a) cement-LS binary blends (b) cement-MK binary blends
Advances in Materials Science and Engineering 9
0 02 04 06 08 1MK(MK + limestone) weight fraction
19
195
20
205
21
215
221
5-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
Metakaolin + limestoneBase Portland cement
(a)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
25
26
27
28
29
30
3-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(b)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
35
40
45
50
55
60
28-d
ay co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(c)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
45
50
55
60
65
7090
-day
com
pres
sive s
treng
th (M
Pa)
70 PC + 30 (MK-limestone mix)
(d)
0 20 40 60 80 100Time (days)
02
03
04
05
06
07
08
Opt
imum
wei
ght f
ract
ion
in M
K +
limes
tone
ble
nds
70 PC + 30 (MK-limestone mix)
MK
(e)
Figure 6 Synergetic effect of cement-MK-LS ternary blends (MK+LS 30) (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimumfractions of MK
10 Advances in Materials Science and Engineering
age of 90 days the concrete with a higher metakaolincontent and a lower limestone content has higheststrength (shown in Figure 7(d)) In other words toachieve the highest strength of cement-metakaolin-limestone ternary blends the optimum combination ofmetakaolin and limestone is dependent on ages From theearly age to late age the optimum combinations change
shift from high limestone-low metakaolin zone to lowlimestone-high metakaolin zone (shown in Figure 7(e))
4 Conclusions
+is study presents an integrated hydration-strength modelfor cement-limestone-metakaolin ternary blends
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03M
K w
eigh
t fra
ctio
n in
tota
l bin
der
195
20
205
21
215
(a)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
265
27
275
28
285
29
295
(b)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
44
46
48
50
52
54
56
(c)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
52
54
56
58
60
62
64
66
68
(d)
008 01 012 014 016 018MK weight fraction in total binder
0
005
01
015
02
Lim
esto
ne w
eigh
t fra
ctio
n in
tota
l bin
der
15 days
3 days
28 days and90 days
(e)
Figure 7 Analysis of optimum MK and LS combinations (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimum MK and LScombinations at different ages
Advances in Materials Science and Engineering 11
First a cement hydration model a metakaolin reactionmodel and a limestone reaction model are proposed in theternary-blended hydration model Pozzolanic reaction ofmetakaolin chemical and physics effect of limestone andsynergetic effect between metakaolin and limestone aredetailed considered in the ternary-blended hydration modelMoreover the interactions among cement hydrationlimestone reaction and metakaolin reaction are consideredthrough the contents of calcium hydroxide and capillarywater+e coefficients of the hydration model do not changefor various concrete mixtures
Second based on the hydration model the gel-spaceratio of hydrating blends is calculated considering thecontributions from the reactions of cement metakaolin andlimestone Furthermore the strength development of ter-nary blends is evaluated using the gel-space ratio +e co-efficients of the strength model do not change for variousconcrete mixtures Based on parameter analysis the syn-ergetic effect on strength development is shown and theoptimal combinations of cement-limestone-metakaolinternary blends are determined From the early age to lateage the optimum combinations of ternary blends shift fromhigh limestone-low metakaolin zone to low limestone-highmetakaolin zone
Data Availability
+e data used to support the findings of this study are in-cluded within the article
Conflicts of Interest
+e author declares that there are no conflicts of interestregarding the publication of this paper
Acknowledgments
+is research was supported by Basic Science ResearchProgram through the National Research Foundation ofKorea (NRF) funded by the Ministry of Science ICT andFuture Planning (no 2015R1A5A1037548) and a NRF grant(NRF-2017R1C1B1010076)
References
[1] X-Y Wang ldquoModeling of hydration compressive strengthand carbonation of Portland-limestone cement (PLC) con-creterdquo Materials vol 10 no 2 pp 115ndash131 2017
[2] X Y Wang and Y Luan ldquoModeling of hydration strengthdevelopment and optimum combinations of cement-slag-limestone ternary concreterdquo International Journal of Con-crete Structures and Materials vol 12 no 1 pp 193ndash2062018
[3] K Vance A Kumar G Sant and N Neithalath ldquo+e rhe-ological properties of ternary binders containing Portlandcement limestone and metakaolin or fly ashrdquo Cement andConcrete Research vol 52 pp 196ndash207 2013
[4] K Vance M Aguayo T Oey G Sant and N NeithalathldquoHydration and strength development in ternary portlandcement blends containing limestone and fly ash or
metakaolinrdquo Cement and Concrete Composites vol 39pp 93ndash103 2013
[5] G L Alvarez A Nazari A Bagheri J G Sanjayan andC De Lange ldquoMicrostructure electrical and mechanicalproperties of steel fibres reinforced cement mortars withpartial metakaolin and limestone additionrdquo Construction andBuilding Materials vol 135 pp 8ndash20 2017
[6] A M Ramezanianpour and R D Hooton ldquoA study on hy-dration compressive strength and porosity of Portland-limestone cement mixes containing SCMsrdquo Cement andConcrete Composites vol 51 pp 1ndash13 2014
[7] C Perlot P Rougeau and S Dehaudt ldquoSlurry of metakaolincombined with limestone addition for self-compacted con-crete application for precast industryrdquo Cement and ConcreteComposites vol 44 pp 50ndash57 2013
[8] K Sotiriadis E Nikolopoulou S Tsivilis A PavlouE Chaniotakis and R N Swamy ldquo+e effect of chlorides onthe thaumasite form of sulfate attack of limestone cementconcrete containing mineral admixtures at low temperaturerdquoConstruction and Building Materials vol 43 pp 156ndash1642013
[9] M Antoni J Rossen F Martirena and K Scrivener ldquoCementsubstitution by a combination of metakaolin and limestonerdquoCement and Concrete Research vol 42 no 12 pp 1579ndash15892012
[10] Z Shi M R Geiker K De Weerdt et al ldquoRole of calcium onchloride binding in hydrated Portland cement-metakaolin-limestone blendsrdquo Cement and Concrete Research vol 95pp 205ndash216 2017
[11] Z Shi B Lothenbach M R Geiker et al ldquoExperimentalstudies and thermodynamic modeling of the carbonation ofPortland cement metakaolin and limestonemortarsrdquo Cementand Concrete Research vol 88 pp 60ndash72 2016
[12] X-Y Wang and H-S Lee ldquoModeling the hydration ofconcrete incorporating fly ash or slagrdquo Cement and ConcreteResearch vol 40 no 7 pp 984ndash996 2010
[13] K Maekawa R Chaube and T Kishi Modelling of ConcretePerformance Hydration Microstructure and Mass TransportCRC Press London UK 1999
[14] K van Breugel Simulation of Hydration and Formation ofStructure in Hardening Cement-Based Materials Delft Uni-versity Press Delft Netherlands 1997
[15] X-Y Wang ldquoAnalysis of hydration-mechanical-durabilityproperties of metakaolin blended concreterdquo Applied Sci-ences vol 7 no 10 pp 1087ndash1102 2017
[16] V G Papadakis ldquoExperimental investigation and theoreticalmodeling of silica fume activity in concreterdquo Cement andConcrete Research vol 29 no 1 pp 79ndash86 1999
[17] Y Elakneswaran E Owaki S Miyahara M OginoT Maruya and T Nawa ldquoHydration study of slag-blendedcement based on thermodynamic considerationsrdquo Con-struction and Building Materials vol 124 pp 615ndash625 2016
[18] T Vuk V Tinta R Gabrovsek and V Kaucic ldquo+e effects oflimestone addition clinker type and fineness on properties ofPortland cementrdquo Cement and Concrete Research vol 31no 1 pp 135ndash139 2001
[19] V Bonavetti H Donza G Menendez O Cabrera andE F Irassar ldquoLimestone filler cement in low wc concrete arational use of energyrdquo Cement and Concrete Researchvol 33 no 6 pp 865ndash871 2003
[20] A M Dunster J R Parsonage and M J K +omas ldquo+epozzolanic reaction of metakaolinite and its effects onPortland cement hydrationrdquo Journal of Materials Sciencevol 28 no 5 pp 1345ndash1350 1993
12 Advances in Materials Science and Engineering
[21] D P Bentz ldquoModeling the influence of limestone filler oncement hydration using CEMHYD3Drdquo Cement and ConcreteComposites vol 28 no 2 pp 124ndash129 2006
[22] B Pichler C Hellmich J Eberhardsteiner et al ldquoEffect of gel-space ratio and microstructure on strength of hydrating ce-mentitious materials an engineering micromechanics ap-proachrdquo Cement and Concrete Research vol 45 pp 55ndash682013
[23] M Aqel and D K Panesar ldquoHydration kinetics and com-pressive strength of steam-cured cement pastes and mortarscontaining limestone fillerrdquo Construction and Building Ma-terials vol 113 pp 359ndash368 2016
[24] C-S Poon L Lam S C Kou Y-L Wong and R WongldquoRate of pozzolanic reaction of metakaolin in high-performance cement pastesrdquo Cement and Concrete Re-search vol 31 no 9 pp 1301ndash1306 2001
[25] L Lam Y L Wong and C S Poon ldquoDegree of hydration andgelspace ratio of high-volume fly ashcement systemsrdquo Ce-ment and Concrete Research vol 30 no 5 pp 747ndash756 2000
[26] D Damidot B Lothenbach D Herfort and F P Glasserldquo+ermodynamics and cement sciencerdquo Cement and ConcreteResearch vol 41 no 7 pp 679ndash695 2011
Advances in Materials Science and Engineering 13
CorrosionInternational Journal of
Hindawiwwwhindawicom Volume 2018
Advances in
Materials Science and EngineeringHindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Journal of
Chemistry
Analytical ChemistryInternational Journal of
Hindawiwwwhindawicom Volume 2018
ScienticaHindawiwwwhindawicom Volume 2018
Polymer ScienceInternational Journal of
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Advances in Condensed Matter Physics
Hindawiwwwhindawicom Volume 2018
International Journal of
BiomaterialsHindawiwwwhindawicom
Journal ofEngineeringVolume 2018
Applied ChemistryJournal of
Hindawiwwwhindawicom Volume 2018
NanotechnologyHindawiwwwhindawicom Volume 2018
Journal of
Hindawiwwwhindawicom Volume 2018
High Energy PhysicsAdvances in
Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom
The Scientific World Journal
Volume 2018
TribologyAdvances in
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
ChemistryAdvances in
Hindawiwwwhindawicom Volume 2018
Advances inPhysical Chemistry
Hindawiwwwhindawicom Volume 2018
BioMed Research InternationalMaterials
Journal of
Hindawiwwwhindawicom Volume 2018
Na
nom
ate
ria
ls
Hindawiwwwhindawicom Volume 2018
Journal ofNanomaterials
Submit your manuscripts atwwwhindawicom
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70C
ompr
essiv
e stre
ngth
(MPa
)
Analysis resultsExperimental results
Control
(a)
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
Analysis resultsExperimental results
(b)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
(c)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70C
ompr
essiv
e stre
ngth
(MPa
)MK 10 limestone 5
(d)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 20 limestone 10
(e)
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 30 limestone 20
(f )
Figure 4 Continued
8 Advances in Materials Science and Engineering
(mk+ limestone) ratios of 25 50 75 and 100 be-cause the reaction of metakaolin can contribute to thestrength the strength of blended concrete is higher than basePortland cement
At the age of 15 days 3 days 28 days and 90 days theoptimum weight fractions of clay(clay + limestone) are 2550 75 and 75 respectively (shown in Figures 6(e)) Ouranalysis result about optimum weight fraction of clay(clay + limestone) is similar to that of Damidot et al [26]studies In addition our analysis shows that at the ages of15 days 3 days 28 days and 90 days the optimum weightfraction of limestone(clay + limestone) is 75 50 25 and25 respectively It means that at the early age limestone iseffective to improve the strength of concrete (this is because of
the nucleation effect of limestone) and at the late agemetakaolin is effective to improve the strength of concrete(this is because of the pozzolanic reaction of metakaolin)
In Figure 6 the sum of metakaolin and limestone isfixed as 30 To find the optimum combinations of ce-ment metakaolin and limestone we make much widerparameter analysis In this wider parameter analysis thesum of metakaolin and limestone is not a fixed value +econtents of metakaolin vary from 0 to 30 and thecontents of limestone vary from 0 to 20 +e analysisresults of isoline of strength are shown in Figures 7(a)ndash7(d) At the early age 15 days the concrete with a higherlimestone content and a lower metakaolin content hashighest strength (shown in Figure 7(a)) while at the late
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 40 limestone 20
(g)
Figure 4 Analysis of compressive strength (a) PC (b) LS15 (c) MK30 (d) B15 (e) B30 (f ) B45 (g) B60
10ndash2 100 102 104
Time (hours)
0
10
20
30
40
50
60
Com
pres
sive s
treng
th (M
Pa)
ControlLS10LS20
(a)
ControlMK5MK10
10ndash2 100 102 104
Time (hours)
0
20
40
60
80
Com
pres
sive s
treng
th (M
Pa)
(b)
Figure 5 Effect of LS and MK on strength development (a) cement-LS binary blends (b) cement-MK binary blends
Advances in Materials Science and Engineering 9
0 02 04 06 08 1MK(MK + limestone) weight fraction
19
195
20
205
21
215
221
5-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
Metakaolin + limestoneBase Portland cement
(a)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
25
26
27
28
29
30
3-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(b)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
35
40
45
50
55
60
28-d
ay co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(c)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
45
50
55
60
65
7090
-day
com
pres
sive s
treng
th (M
Pa)
70 PC + 30 (MK-limestone mix)
(d)
0 20 40 60 80 100Time (days)
02
03
04
05
06
07
08
Opt
imum
wei
ght f
ract
ion
in M
K +
limes
tone
ble
nds
70 PC + 30 (MK-limestone mix)
MK
(e)
Figure 6 Synergetic effect of cement-MK-LS ternary blends (MK+LS 30) (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimumfractions of MK
10 Advances in Materials Science and Engineering
age of 90 days the concrete with a higher metakaolincontent and a lower limestone content has higheststrength (shown in Figure 7(d)) In other words toachieve the highest strength of cement-metakaolin-limestone ternary blends the optimum combination ofmetakaolin and limestone is dependent on ages From theearly age to late age the optimum combinations change
shift from high limestone-low metakaolin zone to lowlimestone-high metakaolin zone (shown in Figure 7(e))
4 Conclusions
+is study presents an integrated hydration-strength modelfor cement-limestone-metakaolin ternary blends
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03M
K w
eigh
t fra
ctio
n in
tota
l bin
der
195
20
205
21
215
(a)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
265
27
275
28
285
29
295
(b)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
44
46
48
50
52
54
56
(c)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
52
54
56
58
60
62
64
66
68
(d)
008 01 012 014 016 018MK weight fraction in total binder
0
005
01
015
02
Lim
esto
ne w
eigh
t fra
ctio
n in
tota
l bin
der
15 days
3 days
28 days and90 days
(e)
Figure 7 Analysis of optimum MK and LS combinations (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimum MK and LScombinations at different ages
Advances in Materials Science and Engineering 11
First a cement hydration model a metakaolin reactionmodel and a limestone reaction model are proposed in theternary-blended hydration model Pozzolanic reaction ofmetakaolin chemical and physics effect of limestone andsynergetic effect between metakaolin and limestone aredetailed considered in the ternary-blended hydration modelMoreover the interactions among cement hydrationlimestone reaction and metakaolin reaction are consideredthrough the contents of calcium hydroxide and capillarywater+e coefficients of the hydration model do not changefor various concrete mixtures
Second based on the hydration model the gel-spaceratio of hydrating blends is calculated considering thecontributions from the reactions of cement metakaolin andlimestone Furthermore the strength development of ter-nary blends is evaluated using the gel-space ratio +e co-efficients of the strength model do not change for variousconcrete mixtures Based on parameter analysis the syn-ergetic effect on strength development is shown and theoptimal combinations of cement-limestone-metakaolinternary blends are determined From the early age to lateage the optimum combinations of ternary blends shift fromhigh limestone-low metakaolin zone to low limestone-highmetakaolin zone
Data Availability
+e data used to support the findings of this study are in-cluded within the article
Conflicts of Interest
+e author declares that there are no conflicts of interestregarding the publication of this paper
Acknowledgments
+is research was supported by Basic Science ResearchProgram through the National Research Foundation ofKorea (NRF) funded by the Ministry of Science ICT andFuture Planning (no 2015R1A5A1037548) and a NRF grant(NRF-2017R1C1B1010076)
References
[1] X-Y Wang ldquoModeling of hydration compressive strengthand carbonation of Portland-limestone cement (PLC) con-creterdquo Materials vol 10 no 2 pp 115ndash131 2017
[2] X Y Wang and Y Luan ldquoModeling of hydration strengthdevelopment and optimum combinations of cement-slag-limestone ternary concreterdquo International Journal of Con-crete Structures and Materials vol 12 no 1 pp 193ndash2062018
[3] K Vance A Kumar G Sant and N Neithalath ldquo+e rhe-ological properties of ternary binders containing Portlandcement limestone and metakaolin or fly ashrdquo Cement andConcrete Research vol 52 pp 196ndash207 2013
[4] K Vance M Aguayo T Oey G Sant and N NeithalathldquoHydration and strength development in ternary portlandcement blends containing limestone and fly ash or
metakaolinrdquo Cement and Concrete Composites vol 39pp 93ndash103 2013
[5] G L Alvarez A Nazari A Bagheri J G Sanjayan andC De Lange ldquoMicrostructure electrical and mechanicalproperties of steel fibres reinforced cement mortars withpartial metakaolin and limestone additionrdquo Construction andBuilding Materials vol 135 pp 8ndash20 2017
[6] A M Ramezanianpour and R D Hooton ldquoA study on hy-dration compressive strength and porosity of Portland-limestone cement mixes containing SCMsrdquo Cement andConcrete Composites vol 51 pp 1ndash13 2014
[7] C Perlot P Rougeau and S Dehaudt ldquoSlurry of metakaolincombined with limestone addition for self-compacted con-crete application for precast industryrdquo Cement and ConcreteComposites vol 44 pp 50ndash57 2013
[8] K Sotiriadis E Nikolopoulou S Tsivilis A PavlouE Chaniotakis and R N Swamy ldquo+e effect of chlorides onthe thaumasite form of sulfate attack of limestone cementconcrete containing mineral admixtures at low temperaturerdquoConstruction and Building Materials vol 43 pp 156ndash1642013
[9] M Antoni J Rossen F Martirena and K Scrivener ldquoCementsubstitution by a combination of metakaolin and limestonerdquoCement and Concrete Research vol 42 no 12 pp 1579ndash15892012
[10] Z Shi M R Geiker K De Weerdt et al ldquoRole of calcium onchloride binding in hydrated Portland cement-metakaolin-limestone blendsrdquo Cement and Concrete Research vol 95pp 205ndash216 2017
[11] Z Shi B Lothenbach M R Geiker et al ldquoExperimentalstudies and thermodynamic modeling of the carbonation ofPortland cement metakaolin and limestonemortarsrdquo Cementand Concrete Research vol 88 pp 60ndash72 2016
[12] X-Y Wang and H-S Lee ldquoModeling the hydration ofconcrete incorporating fly ash or slagrdquo Cement and ConcreteResearch vol 40 no 7 pp 984ndash996 2010
[13] K Maekawa R Chaube and T Kishi Modelling of ConcretePerformance Hydration Microstructure and Mass TransportCRC Press London UK 1999
[14] K van Breugel Simulation of Hydration and Formation ofStructure in Hardening Cement-Based Materials Delft Uni-versity Press Delft Netherlands 1997
[15] X-Y Wang ldquoAnalysis of hydration-mechanical-durabilityproperties of metakaolin blended concreterdquo Applied Sci-ences vol 7 no 10 pp 1087ndash1102 2017
[16] V G Papadakis ldquoExperimental investigation and theoreticalmodeling of silica fume activity in concreterdquo Cement andConcrete Research vol 29 no 1 pp 79ndash86 1999
[17] Y Elakneswaran E Owaki S Miyahara M OginoT Maruya and T Nawa ldquoHydration study of slag-blendedcement based on thermodynamic considerationsrdquo Con-struction and Building Materials vol 124 pp 615ndash625 2016
[18] T Vuk V Tinta R Gabrovsek and V Kaucic ldquo+e effects oflimestone addition clinker type and fineness on properties ofPortland cementrdquo Cement and Concrete Research vol 31no 1 pp 135ndash139 2001
[19] V Bonavetti H Donza G Menendez O Cabrera andE F Irassar ldquoLimestone filler cement in low wc concrete arational use of energyrdquo Cement and Concrete Researchvol 33 no 6 pp 865ndash871 2003
[20] A M Dunster J R Parsonage and M J K +omas ldquo+epozzolanic reaction of metakaolinite and its effects onPortland cement hydrationrdquo Journal of Materials Sciencevol 28 no 5 pp 1345ndash1350 1993
12 Advances in Materials Science and Engineering
[21] D P Bentz ldquoModeling the influence of limestone filler oncement hydration using CEMHYD3Drdquo Cement and ConcreteComposites vol 28 no 2 pp 124ndash129 2006
[22] B Pichler C Hellmich J Eberhardsteiner et al ldquoEffect of gel-space ratio and microstructure on strength of hydrating ce-mentitious materials an engineering micromechanics ap-proachrdquo Cement and Concrete Research vol 45 pp 55ndash682013
[23] M Aqel and D K Panesar ldquoHydration kinetics and com-pressive strength of steam-cured cement pastes and mortarscontaining limestone fillerrdquo Construction and Building Ma-terials vol 113 pp 359ndash368 2016
[24] C-S Poon L Lam S C Kou Y-L Wong and R WongldquoRate of pozzolanic reaction of metakaolin in high-performance cement pastesrdquo Cement and Concrete Re-search vol 31 no 9 pp 1301ndash1306 2001
[25] L Lam Y L Wong and C S Poon ldquoDegree of hydration andgelspace ratio of high-volume fly ashcement systemsrdquo Ce-ment and Concrete Research vol 30 no 5 pp 747ndash756 2000
[26] D Damidot B Lothenbach D Herfort and F P Glasserldquo+ermodynamics and cement sciencerdquo Cement and ConcreteResearch vol 41 no 7 pp 679ndash695 2011
Advances in Materials Science and Engineering 13
CorrosionInternational Journal of
Hindawiwwwhindawicom Volume 2018
Advances in
Materials Science and EngineeringHindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Journal of
Chemistry
Analytical ChemistryInternational Journal of
Hindawiwwwhindawicom Volume 2018
ScienticaHindawiwwwhindawicom Volume 2018
Polymer ScienceInternational Journal of
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Advances in Condensed Matter Physics
Hindawiwwwhindawicom Volume 2018
International Journal of
BiomaterialsHindawiwwwhindawicom
Journal ofEngineeringVolume 2018
Applied ChemistryJournal of
Hindawiwwwhindawicom Volume 2018
NanotechnologyHindawiwwwhindawicom Volume 2018
Journal of
Hindawiwwwhindawicom Volume 2018
High Energy PhysicsAdvances in
Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom
The Scientific World Journal
Volume 2018
TribologyAdvances in
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
ChemistryAdvances in
Hindawiwwwhindawicom Volume 2018
Advances inPhysical Chemistry
Hindawiwwwhindawicom Volume 2018
BioMed Research InternationalMaterials
Journal of
Hindawiwwwhindawicom Volume 2018
Na
nom
ate
ria
ls
Hindawiwwwhindawicom Volume 2018
Journal ofNanomaterials
Submit your manuscripts atwwwhindawicom
(mk+ limestone) ratios of 25 50 75 and 100 be-cause the reaction of metakaolin can contribute to thestrength the strength of blended concrete is higher than basePortland cement
At the age of 15 days 3 days 28 days and 90 days theoptimum weight fractions of clay(clay + limestone) are 2550 75 and 75 respectively (shown in Figures 6(e)) Ouranalysis result about optimum weight fraction of clay(clay + limestone) is similar to that of Damidot et al [26]studies In addition our analysis shows that at the ages of15 days 3 days 28 days and 90 days the optimum weightfraction of limestone(clay + limestone) is 75 50 25 and25 respectively It means that at the early age limestone iseffective to improve the strength of concrete (this is because of
the nucleation effect of limestone) and at the late agemetakaolin is effective to improve the strength of concrete(this is because of the pozzolanic reaction of metakaolin)
In Figure 6 the sum of metakaolin and limestone isfixed as 30 To find the optimum combinations of ce-ment metakaolin and limestone we make much widerparameter analysis In this wider parameter analysis thesum of metakaolin and limestone is not a fixed value +econtents of metakaolin vary from 0 to 30 and thecontents of limestone vary from 0 to 20 +e analysisresults of isoline of strength are shown in Figures 7(a)ndash7(d) At the early age 15 days the concrete with a higherlimestone content and a lower metakaolin content hashighest strength (shown in Figure 7(a)) while at the late
Analysis resultsExperimental results
0 20 40 60 80 100Time (days)
0
10
20
30
40
50
60
70
Com
pres
sive s
treng
th (M
Pa)
MK 40 limestone 20
(g)
Figure 4 Analysis of compressive strength (a) PC (b) LS15 (c) MK30 (d) B15 (e) B30 (f ) B45 (g) B60
10ndash2 100 102 104
Time (hours)
0
10
20
30
40
50
60
Com
pres
sive s
treng
th (M
Pa)
ControlLS10LS20
(a)
ControlMK5MK10
10ndash2 100 102 104
Time (hours)
0
20
40
60
80
Com
pres
sive s
treng
th (M
Pa)
(b)
Figure 5 Effect of LS and MK on strength development (a) cement-LS binary blends (b) cement-MK binary blends
Advances in Materials Science and Engineering 9
0 02 04 06 08 1MK(MK + limestone) weight fraction
19
195
20
205
21
215
221
5-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
Metakaolin + limestoneBase Portland cement
(a)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
25
26
27
28
29
30
3-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(b)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
35
40
45
50
55
60
28-d
ay co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(c)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
45
50
55
60
65
7090
-day
com
pres
sive s
treng
th (M
Pa)
70 PC + 30 (MK-limestone mix)
(d)
0 20 40 60 80 100Time (days)
02
03
04
05
06
07
08
Opt
imum
wei
ght f
ract
ion
in M
K +
limes
tone
ble
nds
70 PC + 30 (MK-limestone mix)
MK
(e)
Figure 6 Synergetic effect of cement-MK-LS ternary blends (MK+LS 30) (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimumfractions of MK
10 Advances in Materials Science and Engineering
age of 90 days the concrete with a higher metakaolincontent and a lower limestone content has higheststrength (shown in Figure 7(d)) In other words toachieve the highest strength of cement-metakaolin-limestone ternary blends the optimum combination ofmetakaolin and limestone is dependent on ages From theearly age to late age the optimum combinations change
shift from high limestone-low metakaolin zone to lowlimestone-high metakaolin zone (shown in Figure 7(e))
4 Conclusions
+is study presents an integrated hydration-strength modelfor cement-limestone-metakaolin ternary blends
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03M
K w
eigh
t fra
ctio
n in
tota
l bin
der
195
20
205
21
215
(a)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
265
27
275
28
285
29
295
(b)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
44
46
48
50
52
54
56
(c)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
52
54
56
58
60
62
64
66
68
(d)
008 01 012 014 016 018MK weight fraction in total binder
0
005
01
015
02
Lim
esto
ne w
eigh
t fra
ctio
n in
tota
l bin
der
15 days
3 days
28 days and90 days
(e)
Figure 7 Analysis of optimum MK and LS combinations (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimum MK and LScombinations at different ages
Advances in Materials Science and Engineering 11
First a cement hydration model a metakaolin reactionmodel and a limestone reaction model are proposed in theternary-blended hydration model Pozzolanic reaction ofmetakaolin chemical and physics effect of limestone andsynergetic effect between metakaolin and limestone aredetailed considered in the ternary-blended hydration modelMoreover the interactions among cement hydrationlimestone reaction and metakaolin reaction are consideredthrough the contents of calcium hydroxide and capillarywater+e coefficients of the hydration model do not changefor various concrete mixtures
Second based on the hydration model the gel-spaceratio of hydrating blends is calculated considering thecontributions from the reactions of cement metakaolin andlimestone Furthermore the strength development of ter-nary blends is evaluated using the gel-space ratio +e co-efficients of the strength model do not change for variousconcrete mixtures Based on parameter analysis the syn-ergetic effect on strength development is shown and theoptimal combinations of cement-limestone-metakaolinternary blends are determined From the early age to lateage the optimum combinations of ternary blends shift fromhigh limestone-low metakaolin zone to low limestone-highmetakaolin zone
Data Availability
+e data used to support the findings of this study are in-cluded within the article
Conflicts of Interest
+e author declares that there are no conflicts of interestregarding the publication of this paper
Acknowledgments
+is research was supported by Basic Science ResearchProgram through the National Research Foundation ofKorea (NRF) funded by the Ministry of Science ICT andFuture Planning (no 2015R1A5A1037548) and a NRF grant(NRF-2017R1C1B1010076)
References
[1] X-Y Wang ldquoModeling of hydration compressive strengthand carbonation of Portland-limestone cement (PLC) con-creterdquo Materials vol 10 no 2 pp 115ndash131 2017
[2] X Y Wang and Y Luan ldquoModeling of hydration strengthdevelopment and optimum combinations of cement-slag-limestone ternary concreterdquo International Journal of Con-crete Structures and Materials vol 12 no 1 pp 193ndash2062018
[3] K Vance A Kumar G Sant and N Neithalath ldquo+e rhe-ological properties of ternary binders containing Portlandcement limestone and metakaolin or fly ashrdquo Cement andConcrete Research vol 52 pp 196ndash207 2013
[4] K Vance M Aguayo T Oey G Sant and N NeithalathldquoHydration and strength development in ternary portlandcement blends containing limestone and fly ash or
metakaolinrdquo Cement and Concrete Composites vol 39pp 93ndash103 2013
[5] G L Alvarez A Nazari A Bagheri J G Sanjayan andC De Lange ldquoMicrostructure electrical and mechanicalproperties of steel fibres reinforced cement mortars withpartial metakaolin and limestone additionrdquo Construction andBuilding Materials vol 135 pp 8ndash20 2017
[6] A M Ramezanianpour and R D Hooton ldquoA study on hy-dration compressive strength and porosity of Portland-limestone cement mixes containing SCMsrdquo Cement andConcrete Composites vol 51 pp 1ndash13 2014
[7] C Perlot P Rougeau and S Dehaudt ldquoSlurry of metakaolincombined with limestone addition for self-compacted con-crete application for precast industryrdquo Cement and ConcreteComposites vol 44 pp 50ndash57 2013
[8] K Sotiriadis E Nikolopoulou S Tsivilis A PavlouE Chaniotakis and R N Swamy ldquo+e effect of chlorides onthe thaumasite form of sulfate attack of limestone cementconcrete containing mineral admixtures at low temperaturerdquoConstruction and Building Materials vol 43 pp 156ndash1642013
[9] M Antoni J Rossen F Martirena and K Scrivener ldquoCementsubstitution by a combination of metakaolin and limestonerdquoCement and Concrete Research vol 42 no 12 pp 1579ndash15892012
[10] Z Shi M R Geiker K De Weerdt et al ldquoRole of calcium onchloride binding in hydrated Portland cement-metakaolin-limestone blendsrdquo Cement and Concrete Research vol 95pp 205ndash216 2017
[11] Z Shi B Lothenbach M R Geiker et al ldquoExperimentalstudies and thermodynamic modeling of the carbonation ofPortland cement metakaolin and limestonemortarsrdquo Cementand Concrete Research vol 88 pp 60ndash72 2016
[12] X-Y Wang and H-S Lee ldquoModeling the hydration ofconcrete incorporating fly ash or slagrdquo Cement and ConcreteResearch vol 40 no 7 pp 984ndash996 2010
[13] K Maekawa R Chaube and T Kishi Modelling of ConcretePerformance Hydration Microstructure and Mass TransportCRC Press London UK 1999
[14] K van Breugel Simulation of Hydration and Formation ofStructure in Hardening Cement-Based Materials Delft Uni-versity Press Delft Netherlands 1997
[15] X-Y Wang ldquoAnalysis of hydration-mechanical-durabilityproperties of metakaolin blended concreterdquo Applied Sci-ences vol 7 no 10 pp 1087ndash1102 2017
[16] V G Papadakis ldquoExperimental investigation and theoreticalmodeling of silica fume activity in concreterdquo Cement andConcrete Research vol 29 no 1 pp 79ndash86 1999
[17] Y Elakneswaran E Owaki S Miyahara M OginoT Maruya and T Nawa ldquoHydration study of slag-blendedcement based on thermodynamic considerationsrdquo Con-struction and Building Materials vol 124 pp 615ndash625 2016
[18] T Vuk V Tinta R Gabrovsek and V Kaucic ldquo+e effects oflimestone addition clinker type and fineness on properties ofPortland cementrdquo Cement and Concrete Research vol 31no 1 pp 135ndash139 2001
[19] V Bonavetti H Donza G Menendez O Cabrera andE F Irassar ldquoLimestone filler cement in low wc concrete arational use of energyrdquo Cement and Concrete Researchvol 33 no 6 pp 865ndash871 2003
[20] A M Dunster J R Parsonage and M J K +omas ldquo+epozzolanic reaction of metakaolinite and its effects onPortland cement hydrationrdquo Journal of Materials Sciencevol 28 no 5 pp 1345ndash1350 1993
12 Advances in Materials Science and Engineering
[21] D P Bentz ldquoModeling the influence of limestone filler oncement hydration using CEMHYD3Drdquo Cement and ConcreteComposites vol 28 no 2 pp 124ndash129 2006
[22] B Pichler C Hellmich J Eberhardsteiner et al ldquoEffect of gel-space ratio and microstructure on strength of hydrating ce-mentitious materials an engineering micromechanics ap-proachrdquo Cement and Concrete Research vol 45 pp 55ndash682013
[23] M Aqel and D K Panesar ldquoHydration kinetics and com-pressive strength of steam-cured cement pastes and mortarscontaining limestone fillerrdquo Construction and Building Ma-terials vol 113 pp 359ndash368 2016
[24] C-S Poon L Lam S C Kou Y-L Wong and R WongldquoRate of pozzolanic reaction of metakaolin in high-performance cement pastesrdquo Cement and Concrete Re-search vol 31 no 9 pp 1301ndash1306 2001
[25] L Lam Y L Wong and C S Poon ldquoDegree of hydration andgelspace ratio of high-volume fly ashcement systemsrdquo Ce-ment and Concrete Research vol 30 no 5 pp 747ndash756 2000
[26] D Damidot B Lothenbach D Herfort and F P Glasserldquo+ermodynamics and cement sciencerdquo Cement and ConcreteResearch vol 41 no 7 pp 679ndash695 2011
Advances in Materials Science and Engineering 13
CorrosionInternational Journal of
Hindawiwwwhindawicom Volume 2018
Advances in
Materials Science and EngineeringHindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Journal of
Chemistry
Analytical ChemistryInternational Journal of
Hindawiwwwhindawicom Volume 2018
ScienticaHindawiwwwhindawicom Volume 2018
Polymer ScienceInternational Journal of
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Advances in Condensed Matter Physics
Hindawiwwwhindawicom Volume 2018
International Journal of
BiomaterialsHindawiwwwhindawicom
Journal ofEngineeringVolume 2018
Applied ChemistryJournal of
Hindawiwwwhindawicom Volume 2018
NanotechnologyHindawiwwwhindawicom Volume 2018
Journal of
Hindawiwwwhindawicom Volume 2018
High Energy PhysicsAdvances in
Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom
The Scientific World Journal
Volume 2018
TribologyAdvances in
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
ChemistryAdvances in
Hindawiwwwhindawicom Volume 2018
Advances inPhysical Chemistry
Hindawiwwwhindawicom Volume 2018
BioMed Research InternationalMaterials
Journal of
Hindawiwwwhindawicom Volume 2018
Na
nom
ate
ria
ls
Hindawiwwwhindawicom Volume 2018
Journal ofNanomaterials
Submit your manuscripts atwwwhindawicom
0 02 04 06 08 1MK(MK + limestone) weight fraction
19
195
20
205
21
215
221
5-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
Metakaolin + limestoneBase Portland cement
(a)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
25
26
27
28
29
30
3-da
y co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(b)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
35
40
45
50
55
60
28-d
ay co
mpr
essiv
e stre
ngth
(MPa
)
70 PC + 30 (MK-limestone mix)
(c)
Metakaolin + limestoneBase Portland cement
0 02 04 06 08 1MK(MK + limestone) weight fraction
45
50
55
60
65
7090
-day
com
pres
sive s
treng
th (M
Pa)
70 PC + 30 (MK-limestone mix)
(d)
0 20 40 60 80 100Time (days)
02
03
04
05
06
07
08
Opt
imum
wei
ght f
ract
ion
in M
K +
limes
tone
ble
nds
70 PC + 30 (MK-limestone mix)
MK
(e)
Figure 6 Synergetic effect of cement-MK-LS ternary blends (MK+LS 30) (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimumfractions of MK
10 Advances in Materials Science and Engineering
age of 90 days the concrete with a higher metakaolincontent and a lower limestone content has higheststrength (shown in Figure 7(d)) In other words toachieve the highest strength of cement-metakaolin-limestone ternary blends the optimum combination ofmetakaolin and limestone is dependent on ages From theearly age to late age the optimum combinations change
shift from high limestone-low metakaolin zone to lowlimestone-high metakaolin zone (shown in Figure 7(e))
4 Conclusions
+is study presents an integrated hydration-strength modelfor cement-limestone-metakaolin ternary blends
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03M
K w
eigh
t fra
ctio
n in
tota
l bin
der
195
20
205
21
215
(a)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
265
27
275
28
285
29
295
(b)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
44
46
48
50
52
54
56
(c)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
52
54
56
58
60
62
64
66
68
(d)
008 01 012 014 016 018MK weight fraction in total binder
0
005
01
015
02
Lim
esto
ne w
eigh
t fra
ctio
n in
tota
l bin
der
15 days
3 days
28 days and90 days
(e)
Figure 7 Analysis of optimum MK and LS combinations (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimum MK and LScombinations at different ages
Advances in Materials Science and Engineering 11
First a cement hydration model a metakaolin reactionmodel and a limestone reaction model are proposed in theternary-blended hydration model Pozzolanic reaction ofmetakaolin chemical and physics effect of limestone andsynergetic effect between metakaolin and limestone aredetailed considered in the ternary-blended hydration modelMoreover the interactions among cement hydrationlimestone reaction and metakaolin reaction are consideredthrough the contents of calcium hydroxide and capillarywater+e coefficients of the hydration model do not changefor various concrete mixtures
Second based on the hydration model the gel-spaceratio of hydrating blends is calculated considering thecontributions from the reactions of cement metakaolin andlimestone Furthermore the strength development of ter-nary blends is evaluated using the gel-space ratio +e co-efficients of the strength model do not change for variousconcrete mixtures Based on parameter analysis the syn-ergetic effect on strength development is shown and theoptimal combinations of cement-limestone-metakaolinternary blends are determined From the early age to lateage the optimum combinations of ternary blends shift fromhigh limestone-low metakaolin zone to low limestone-highmetakaolin zone
Data Availability
+e data used to support the findings of this study are in-cluded within the article
Conflicts of Interest
+e author declares that there are no conflicts of interestregarding the publication of this paper
Acknowledgments
+is research was supported by Basic Science ResearchProgram through the National Research Foundation ofKorea (NRF) funded by the Ministry of Science ICT andFuture Planning (no 2015R1A5A1037548) and a NRF grant(NRF-2017R1C1B1010076)
References
[1] X-Y Wang ldquoModeling of hydration compressive strengthand carbonation of Portland-limestone cement (PLC) con-creterdquo Materials vol 10 no 2 pp 115ndash131 2017
[2] X Y Wang and Y Luan ldquoModeling of hydration strengthdevelopment and optimum combinations of cement-slag-limestone ternary concreterdquo International Journal of Con-crete Structures and Materials vol 12 no 1 pp 193ndash2062018
[3] K Vance A Kumar G Sant and N Neithalath ldquo+e rhe-ological properties of ternary binders containing Portlandcement limestone and metakaolin or fly ashrdquo Cement andConcrete Research vol 52 pp 196ndash207 2013
[4] K Vance M Aguayo T Oey G Sant and N NeithalathldquoHydration and strength development in ternary portlandcement blends containing limestone and fly ash or
metakaolinrdquo Cement and Concrete Composites vol 39pp 93ndash103 2013
[5] G L Alvarez A Nazari A Bagheri J G Sanjayan andC De Lange ldquoMicrostructure electrical and mechanicalproperties of steel fibres reinforced cement mortars withpartial metakaolin and limestone additionrdquo Construction andBuilding Materials vol 135 pp 8ndash20 2017
[6] A M Ramezanianpour and R D Hooton ldquoA study on hy-dration compressive strength and porosity of Portland-limestone cement mixes containing SCMsrdquo Cement andConcrete Composites vol 51 pp 1ndash13 2014
[7] C Perlot P Rougeau and S Dehaudt ldquoSlurry of metakaolincombined with limestone addition for self-compacted con-crete application for precast industryrdquo Cement and ConcreteComposites vol 44 pp 50ndash57 2013
[8] K Sotiriadis E Nikolopoulou S Tsivilis A PavlouE Chaniotakis and R N Swamy ldquo+e effect of chlorides onthe thaumasite form of sulfate attack of limestone cementconcrete containing mineral admixtures at low temperaturerdquoConstruction and Building Materials vol 43 pp 156ndash1642013
[9] M Antoni J Rossen F Martirena and K Scrivener ldquoCementsubstitution by a combination of metakaolin and limestonerdquoCement and Concrete Research vol 42 no 12 pp 1579ndash15892012
[10] Z Shi M R Geiker K De Weerdt et al ldquoRole of calcium onchloride binding in hydrated Portland cement-metakaolin-limestone blendsrdquo Cement and Concrete Research vol 95pp 205ndash216 2017
[11] Z Shi B Lothenbach M R Geiker et al ldquoExperimentalstudies and thermodynamic modeling of the carbonation ofPortland cement metakaolin and limestonemortarsrdquo Cementand Concrete Research vol 88 pp 60ndash72 2016
[12] X-Y Wang and H-S Lee ldquoModeling the hydration ofconcrete incorporating fly ash or slagrdquo Cement and ConcreteResearch vol 40 no 7 pp 984ndash996 2010
[13] K Maekawa R Chaube and T Kishi Modelling of ConcretePerformance Hydration Microstructure and Mass TransportCRC Press London UK 1999
[14] K van Breugel Simulation of Hydration and Formation ofStructure in Hardening Cement-Based Materials Delft Uni-versity Press Delft Netherlands 1997
[15] X-Y Wang ldquoAnalysis of hydration-mechanical-durabilityproperties of metakaolin blended concreterdquo Applied Sci-ences vol 7 no 10 pp 1087ndash1102 2017
[16] V G Papadakis ldquoExperimental investigation and theoreticalmodeling of silica fume activity in concreterdquo Cement andConcrete Research vol 29 no 1 pp 79ndash86 1999
[17] Y Elakneswaran E Owaki S Miyahara M OginoT Maruya and T Nawa ldquoHydration study of slag-blendedcement based on thermodynamic considerationsrdquo Con-struction and Building Materials vol 124 pp 615ndash625 2016
[18] T Vuk V Tinta R Gabrovsek and V Kaucic ldquo+e effects oflimestone addition clinker type and fineness on properties ofPortland cementrdquo Cement and Concrete Research vol 31no 1 pp 135ndash139 2001
[19] V Bonavetti H Donza G Menendez O Cabrera andE F Irassar ldquoLimestone filler cement in low wc concrete arational use of energyrdquo Cement and Concrete Researchvol 33 no 6 pp 865ndash871 2003
[20] A M Dunster J R Parsonage and M J K +omas ldquo+epozzolanic reaction of metakaolinite and its effects onPortland cement hydrationrdquo Journal of Materials Sciencevol 28 no 5 pp 1345ndash1350 1993
12 Advances in Materials Science and Engineering
[21] D P Bentz ldquoModeling the influence of limestone filler oncement hydration using CEMHYD3Drdquo Cement and ConcreteComposites vol 28 no 2 pp 124ndash129 2006
[22] B Pichler C Hellmich J Eberhardsteiner et al ldquoEffect of gel-space ratio and microstructure on strength of hydrating ce-mentitious materials an engineering micromechanics ap-proachrdquo Cement and Concrete Research vol 45 pp 55ndash682013
[23] M Aqel and D K Panesar ldquoHydration kinetics and com-pressive strength of steam-cured cement pastes and mortarscontaining limestone fillerrdquo Construction and Building Ma-terials vol 113 pp 359ndash368 2016
[24] C-S Poon L Lam S C Kou Y-L Wong and R WongldquoRate of pozzolanic reaction of metakaolin in high-performance cement pastesrdquo Cement and Concrete Re-search vol 31 no 9 pp 1301ndash1306 2001
[25] L Lam Y L Wong and C S Poon ldquoDegree of hydration andgelspace ratio of high-volume fly ashcement systemsrdquo Ce-ment and Concrete Research vol 30 no 5 pp 747ndash756 2000
[26] D Damidot B Lothenbach D Herfort and F P Glasserldquo+ermodynamics and cement sciencerdquo Cement and ConcreteResearch vol 41 no 7 pp 679ndash695 2011
Advances in Materials Science and Engineering 13
CorrosionInternational Journal of
Hindawiwwwhindawicom Volume 2018
Advances in
Materials Science and EngineeringHindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Journal of
Chemistry
Analytical ChemistryInternational Journal of
Hindawiwwwhindawicom Volume 2018
ScienticaHindawiwwwhindawicom Volume 2018
Polymer ScienceInternational Journal of
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Advances in Condensed Matter Physics
Hindawiwwwhindawicom Volume 2018
International Journal of
BiomaterialsHindawiwwwhindawicom
Journal ofEngineeringVolume 2018
Applied ChemistryJournal of
Hindawiwwwhindawicom Volume 2018
NanotechnologyHindawiwwwhindawicom Volume 2018
Journal of
Hindawiwwwhindawicom Volume 2018
High Energy PhysicsAdvances in
Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom
The Scientific World Journal
Volume 2018
TribologyAdvances in
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
ChemistryAdvances in
Hindawiwwwhindawicom Volume 2018
Advances inPhysical Chemistry
Hindawiwwwhindawicom Volume 2018
BioMed Research InternationalMaterials
Journal of
Hindawiwwwhindawicom Volume 2018
Na
nom
ate
ria
ls
Hindawiwwwhindawicom Volume 2018
Journal ofNanomaterials
Submit your manuscripts atwwwhindawicom
age of 90 days the concrete with a higher metakaolincontent and a lower limestone content has higheststrength (shown in Figure 7(d)) In other words toachieve the highest strength of cement-metakaolin-limestone ternary blends the optimum combination ofmetakaolin and limestone is dependent on ages From theearly age to late age the optimum combinations change
shift from high limestone-low metakaolin zone to lowlimestone-high metakaolin zone (shown in Figure 7(e))
4 Conclusions
+is study presents an integrated hydration-strength modelfor cement-limestone-metakaolin ternary blends
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03M
K w
eigh
t fra
ctio
n in
tota
l bin
der
195
20
205
21
215
(a)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
265
27
275
28
285
29
295
(b)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
44
46
48
50
52
54
56
(c)
0 005 01 015 02Limestone weight fraction in total binder
0
005
01
015
02
025
03
MK
wei
ght f
ract
ion
in to
tal b
inde
r
52
54
56
58
60
62
64
66
68
(d)
008 01 012 014 016 018MK weight fraction in total binder
0
005
01
015
02
Lim
esto
ne w
eigh
t fra
ctio
n in
tota
l bin
der
15 days
3 days
28 days and90 days
(e)
Figure 7 Analysis of optimum MK and LS combinations (a) 15 days (b) 3 days (c) 28 days (d) 90 days (e) optimum MK and LScombinations at different ages
Advances in Materials Science and Engineering 11
First a cement hydration model a metakaolin reactionmodel and a limestone reaction model are proposed in theternary-blended hydration model Pozzolanic reaction ofmetakaolin chemical and physics effect of limestone andsynergetic effect between metakaolin and limestone aredetailed considered in the ternary-blended hydration modelMoreover the interactions among cement hydrationlimestone reaction and metakaolin reaction are consideredthrough the contents of calcium hydroxide and capillarywater+e coefficients of the hydration model do not changefor various concrete mixtures
Second based on the hydration model the gel-spaceratio of hydrating blends is calculated considering thecontributions from the reactions of cement metakaolin andlimestone Furthermore the strength development of ter-nary blends is evaluated using the gel-space ratio +e co-efficients of the strength model do not change for variousconcrete mixtures Based on parameter analysis the syn-ergetic effect on strength development is shown and theoptimal combinations of cement-limestone-metakaolinternary blends are determined From the early age to lateage the optimum combinations of ternary blends shift fromhigh limestone-low metakaolin zone to low limestone-highmetakaolin zone
Data Availability
+e data used to support the findings of this study are in-cluded within the article
Conflicts of Interest
+e author declares that there are no conflicts of interestregarding the publication of this paper
Acknowledgments
+is research was supported by Basic Science ResearchProgram through the National Research Foundation ofKorea (NRF) funded by the Ministry of Science ICT andFuture Planning (no 2015R1A5A1037548) and a NRF grant(NRF-2017R1C1B1010076)
References
[1] X-Y Wang ldquoModeling of hydration compressive strengthand carbonation of Portland-limestone cement (PLC) con-creterdquo Materials vol 10 no 2 pp 115ndash131 2017
[2] X Y Wang and Y Luan ldquoModeling of hydration strengthdevelopment and optimum combinations of cement-slag-limestone ternary concreterdquo International Journal of Con-crete Structures and Materials vol 12 no 1 pp 193ndash2062018
[3] K Vance A Kumar G Sant and N Neithalath ldquo+e rhe-ological properties of ternary binders containing Portlandcement limestone and metakaolin or fly ashrdquo Cement andConcrete Research vol 52 pp 196ndash207 2013
[4] K Vance M Aguayo T Oey G Sant and N NeithalathldquoHydration and strength development in ternary portlandcement blends containing limestone and fly ash or
metakaolinrdquo Cement and Concrete Composites vol 39pp 93ndash103 2013
[5] G L Alvarez A Nazari A Bagheri J G Sanjayan andC De Lange ldquoMicrostructure electrical and mechanicalproperties of steel fibres reinforced cement mortars withpartial metakaolin and limestone additionrdquo Construction andBuilding Materials vol 135 pp 8ndash20 2017
[6] A M Ramezanianpour and R D Hooton ldquoA study on hy-dration compressive strength and porosity of Portland-limestone cement mixes containing SCMsrdquo Cement andConcrete Composites vol 51 pp 1ndash13 2014
[7] C Perlot P Rougeau and S Dehaudt ldquoSlurry of metakaolincombined with limestone addition for self-compacted con-crete application for precast industryrdquo Cement and ConcreteComposites vol 44 pp 50ndash57 2013
[8] K Sotiriadis E Nikolopoulou S Tsivilis A PavlouE Chaniotakis and R N Swamy ldquo+e effect of chlorides onthe thaumasite form of sulfate attack of limestone cementconcrete containing mineral admixtures at low temperaturerdquoConstruction and Building Materials vol 43 pp 156ndash1642013
[9] M Antoni J Rossen F Martirena and K Scrivener ldquoCementsubstitution by a combination of metakaolin and limestonerdquoCement and Concrete Research vol 42 no 12 pp 1579ndash15892012
[10] Z Shi M R Geiker K De Weerdt et al ldquoRole of calcium onchloride binding in hydrated Portland cement-metakaolin-limestone blendsrdquo Cement and Concrete Research vol 95pp 205ndash216 2017
[11] Z Shi B Lothenbach M R Geiker et al ldquoExperimentalstudies and thermodynamic modeling of the carbonation ofPortland cement metakaolin and limestonemortarsrdquo Cementand Concrete Research vol 88 pp 60ndash72 2016
[12] X-Y Wang and H-S Lee ldquoModeling the hydration ofconcrete incorporating fly ash or slagrdquo Cement and ConcreteResearch vol 40 no 7 pp 984ndash996 2010
[13] K Maekawa R Chaube and T Kishi Modelling of ConcretePerformance Hydration Microstructure and Mass TransportCRC Press London UK 1999
[14] K van Breugel Simulation of Hydration and Formation ofStructure in Hardening Cement-Based Materials Delft Uni-versity Press Delft Netherlands 1997
[15] X-Y Wang ldquoAnalysis of hydration-mechanical-durabilityproperties of metakaolin blended concreterdquo Applied Sci-ences vol 7 no 10 pp 1087ndash1102 2017
[16] V G Papadakis ldquoExperimental investigation and theoreticalmodeling of silica fume activity in concreterdquo Cement andConcrete Research vol 29 no 1 pp 79ndash86 1999
[17] Y Elakneswaran E Owaki S Miyahara M OginoT Maruya and T Nawa ldquoHydration study of slag-blendedcement based on thermodynamic considerationsrdquo Con-struction and Building Materials vol 124 pp 615ndash625 2016
[18] T Vuk V Tinta R Gabrovsek and V Kaucic ldquo+e effects oflimestone addition clinker type and fineness on properties ofPortland cementrdquo Cement and Concrete Research vol 31no 1 pp 135ndash139 2001
[19] V Bonavetti H Donza G Menendez O Cabrera andE F Irassar ldquoLimestone filler cement in low wc concrete arational use of energyrdquo Cement and Concrete Researchvol 33 no 6 pp 865ndash871 2003
[20] A M Dunster J R Parsonage and M J K +omas ldquo+epozzolanic reaction of metakaolinite and its effects onPortland cement hydrationrdquo Journal of Materials Sciencevol 28 no 5 pp 1345ndash1350 1993
12 Advances in Materials Science and Engineering
[21] D P Bentz ldquoModeling the influence of limestone filler oncement hydration using CEMHYD3Drdquo Cement and ConcreteComposites vol 28 no 2 pp 124ndash129 2006
[22] B Pichler C Hellmich J Eberhardsteiner et al ldquoEffect of gel-space ratio and microstructure on strength of hydrating ce-mentitious materials an engineering micromechanics ap-proachrdquo Cement and Concrete Research vol 45 pp 55ndash682013
[23] M Aqel and D K Panesar ldquoHydration kinetics and com-pressive strength of steam-cured cement pastes and mortarscontaining limestone fillerrdquo Construction and Building Ma-terials vol 113 pp 359ndash368 2016
[24] C-S Poon L Lam S C Kou Y-L Wong and R WongldquoRate of pozzolanic reaction of metakaolin in high-performance cement pastesrdquo Cement and Concrete Re-search vol 31 no 9 pp 1301ndash1306 2001
[25] L Lam Y L Wong and C S Poon ldquoDegree of hydration andgelspace ratio of high-volume fly ashcement systemsrdquo Ce-ment and Concrete Research vol 30 no 5 pp 747ndash756 2000
[26] D Damidot B Lothenbach D Herfort and F P Glasserldquo+ermodynamics and cement sciencerdquo Cement and ConcreteResearch vol 41 no 7 pp 679ndash695 2011
Advances in Materials Science and Engineering 13
CorrosionInternational Journal of
Hindawiwwwhindawicom Volume 2018
Advances in
Materials Science and EngineeringHindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Journal of
Chemistry
Analytical ChemistryInternational Journal of
Hindawiwwwhindawicom Volume 2018
ScienticaHindawiwwwhindawicom Volume 2018
Polymer ScienceInternational Journal of
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Advances in Condensed Matter Physics
Hindawiwwwhindawicom Volume 2018
International Journal of
BiomaterialsHindawiwwwhindawicom
Journal ofEngineeringVolume 2018
Applied ChemistryJournal of
Hindawiwwwhindawicom Volume 2018
NanotechnologyHindawiwwwhindawicom Volume 2018
Journal of
Hindawiwwwhindawicom Volume 2018
High Energy PhysicsAdvances in
Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom
The Scientific World Journal
Volume 2018
TribologyAdvances in
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
ChemistryAdvances in
Hindawiwwwhindawicom Volume 2018
Advances inPhysical Chemistry
Hindawiwwwhindawicom Volume 2018
BioMed Research InternationalMaterials
Journal of
Hindawiwwwhindawicom Volume 2018
Na
nom
ate
ria
ls
Hindawiwwwhindawicom Volume 2018
Journal ofNanomaterials
Submit your manuscripts atwwwhindawicom
First a cement hydration model a metakaolin reactionmodel and a limestone reaction model are proposed in theternary-blended hydration model Pozzolanic reaction ofmetakaolin chemical and physics effect of limestone andsynergetic effect between metakaolin and limestone aredetailed considered in the ternary-blended hydration modelMoreover the interactions among cement hydrationlimestone reaction and metakaolin reaction are consideredthrough the contents of calcium hydroxide and capillarywater+e coefficients of the hydration model do not changefor various concrete mixtures
Second based on the hydration model the gel-spaceratio of hydrating blends is calculated considering thecontributions from the reactions of cement metakaolin andlimestone Furthermore the strength development of ter-nary blends is evaluated using the gel-space ratio +e co-efficients of the strength model do not change for variousconcrete mixtures Based on parameter analysis the syn-ergetic effect on strength development is shown and theoptimal combinations of cement-limestone-metakaolinternary blends are determined From the early age to lateage the optimum combinations of ternary blends shift fromhigh limestone-low metakaolin zone to low limestone-highmetakaolin zone
Data Availability
+e data used to support the findings of this study are in-cluded within the article
Conflicts of Interest
+e author declares that there are no conflicts of interestregarding the publication of this paper
Acknowledgments
+is research was supported by Basic Science ResearchProgram through the National Research Foundation ofKorea (NRF) funded by the Ministry of Science ICT andFuture Planning (no 2015R1A5A1037548) and a NRF grant(NRF-2017R1C1B1010076)
References
[1] X-Y Wang ldquoModeling of hydration compressive strengthand carbonation of Portland-limestone cement (PLC) con-creterdquo Materials vol 10 no 2 pp 115ndash131 2017
[2] X Y Wang and Y Luan ldquoModeling of hydration strengthdevelopment and optimum combinations of cement-slag-limestone ternary concreterdquo International Journal of Con-crete Structures and Materials vol 12 no 1 pp 193ndash2062018
[3] K Vance A Kumar G Sant and N Neithalath ldquo+e rhe-ological properties of ternary binders containing Portlandcement limestone and metakaolin or fly ashrdquo Cement andConcrete Research vol 52 pp 196ndash207 2013
[4] K Vance M Aguayo T Oey G Sant and N NeithalathldquoHydration and strength development in ternary portlandcement blends containing limestone and fly ash or
metakaolinrdquo Cement and Concrete Composites vol 39pp 93ndash103 2013
[5] G L Alvarez A Nazari A Bagheri J G Sanjayan andC De Lange ldquoMicrostructure electrical and mechanicalproperties of steel fibres reinforced cement mortars withpartial metakaolin and limestone additionrdquo Construction andBuilding Materials vol 135 pp 8ndash20 2017
[6] A M Ramezanianpour and R D Hooton ldquoA study on hy-dration compressive strength and porosity of Portland-limestone cement mixes containing SCMsrdquo Cement andConcrete Composites vol 51 pp 1ndash13 2014
[7] C Perlot P Rougeau and S Dehaudt ldquoSlurry of metakaolincombined with limestone addition for self-compacted con-crete application for precast industryrdquo Cement and ConcreteComposites vol 44 pp 50ndash57 2013
[8] K Sotiriadis E Nikolopoulou S Tsivilis A PavlouE Chaniotakis and R N Swamy ldquo+e effect of chlorides onthe thaumasite form of sulfate attack of limestone cementconcrete containing mineral admixtures at low temperaturerdquoConstruction and Building Materials vol 43 pp 156ndash1642013
[9] M Antoni J Rossen F Martirena and K Scrivener ldquoCementsubstitution by a combination of metakaolin and limestonerdquoCement and Concrete Research vol 42 no 12 pp 1579ndash15892012
[10] Z Shi M R Geiker K De Weerdt et al ldquoRole of calcium onchloride binding in hydrated Portland cement-metakaolin-limestone blendsrdquo Cement and Concrete Research vol 95pp 205ndash216 2017
[11] Z Shi B Lothenbach M R Geiker et al ldquoExperimentalstudies and thermodynamic modeling of the carbonation ofPortland cement metakaolin and limestonemortarsrdquo Cementand Concrete Research vol 88 pp 60ndash72 2016
[12] X-Y Wang and H-S Lee ldquoModeling the hydration ofconcrete incorporating fly ash or slagrdquo Cement and ConcreteResearch vol 40 no 7 pp 984ndash996 2010
[13] K Maekawa R Chaube and T Kishi Modelling of ConcretePerformance Hydration Microstructure and Mass TransportCRC Press London UK 1999
[14] K van Breugel Simulation of Hydration and Formation ofStructure in Hardening Cement-Based Materials Delft Uni-versity Press Delft Netherlands 1997
[15] X-Y Wang ldquoAnalysis of hydration-mechanical-durabilityproperties of metakaolin blended concreterdquo Applied Sci-ences vol 7 no 10 pp 1087ndash1102 2017
[16] V G Papadakis ldquoExperimental investigation and theoreticalmodeling of silica fume activity in concreterdquo Cement andConcrete Research vol 29 no 1 pp 79ndash86 1999
[17] Y Elakneswaran E Owaki S Miyahara M OginoT Maruya and T Nawa ldquoHydration study of slag-blendedcement based on thermodynamic considerationsrdquo Con-struction and Building Materials vol 124 pp 615ndash625 2016
[18] T Vuk V Tinta R Gabrovsek and V Kaucic ldquo+e effects oflimestone addition clinker type and fineness on properties ofPortland cementrdquo Cement and Concrete Research vol 31no 1 pp 135ndash139 2001
[19] V Bonavetti H Donza G Menendez O Cabrera andE F Irassar ldquoLimestone filler cement in low wc concrete arational use of energyrdquo Cement and Concrete Researchvol 33 no 6 pp 865ndash871 2003
[20] A M Dunster J R Parsonage and M J K +omas ldquo+epozzolanic reaction of metakaolinite and its effects onPortland cement hydrationrdquo Journal of Materials Sciencevol 28 no 5 pp 1345ndash1350 1993
12 Advances in Materials Science and Engineering
[21] D P Bentz ldquoModeling the influence of limestone filler oncement hydration using CEMHYD3Drdquo Cement and ConcreteComposites vol 28 no 2 pp 124ndash129 2006
[22] B Pichler C Hellmich J Eberhardsteiner et al ldquoEffect of gel-space ratio and microstructure on strength of hydrating ce-mentitious materials an engineering micromechanics ap-proachrdquo Cement and Concrete Research vol 45 pp 55ndash682013
[23] M Aqel and D K Panesar ldquoHydration kinetics and com-pressive strength of steam-cured cement pastes and mortarscontaining limestone fillerrdquo Construction and Building Ma-terials vol 113 pp 359ndash368 2016
[24] C-S Poon L Lam S C Kou Y-L Wong and R WongldquoRate of pozzolanic reaction of metakaolin in high-performance cement pastesrdquo Cement and Concrete Re-search vol 31 no 9 pp 1301ndash1306 2001
[25] L Lam Y L Wong and C S Poon ldquoDegree of hydration andgelspace ratio of high-volume fly ashcement systemsrdquo Ce-ment and Concrete Research vol 30 no 5 pp 747ndash756 2000
[26] D Damidot B Lothenbach D Herfort and F P Glasserldquo+ermodynamics and cement sciencerdquo Cement and ConcreteResearch vol 41 no 7 pp 679ndash695 2011
Advances in Materials Science and Engineering 13
CorrosionInternational Journal of
Hindawiwwwhindawicom Volume 2018
Advances in
Materials Science and EngineeringHindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Journal of
Chemistry
Analytical ChemistryInternational Journal of
Hindawiwwwhindawicom Volume 2018
ScienticaHindawiwwwhindawicom Volume 2018
Polymer ScienceInternational Journal of
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Advances in Condensed Matter Physics
Hindawiwwwhindawicom Volume 2018
International Journal of
BiomaterialsHindawiwwwhindawicom
Journal ofEngineeringVolume 2018
Applied ChemistryJournal of
Hindawiwwwhindawicom Volume 2018
NanotechnologyHindawiwwwhindawicom Volume 2018
Journal of
Hindawiwwwhindawicom Volume 2018
High Energy PhysicsAdvances in
Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom
The Scientific World Journal
Volume 2018
TribologyAdvances in
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
ChemistryAdvances in
Hindawiwwwhindawicom Volume 2018
Advances inPhysical Chemistry
Hindawiwwwhindawicom Volume 2018
BioMed Research InternationalMaterials
Journal of
Hindawiwwwhindawicom Volume 2018
Na
nom
ate
ria
ls
Hindawiwwwhindawicom Volume 2018
Journal ofNanomaterials
Submit your manuscripts atwwwhindawicom
[21] D P Bentz ldquoModeling the influence of limestone filler oncement hydration using CEMHYD3Drdquo Cement and ConcreteComposites vol 28 no 2 pp 124ndash129 2006
[22] B Pichler C Hellmich J Eberhardsteiner et al ldquoEffect of gel-space ratio and microstructure on strength of hydrating ce-mentitious materials an engineering micromechanics ap-proachrdquo Cement and Concrete Research vol 45 pp 55ndash682013
[23] M Aqel and D K Panesar ldquoHydration kinetics and com-pressive strength of steam-cured cement pastes and mortarscontaining limestone fillerrdquo Construction and Building Ma-terials vol 113 pp 359ndash368 2016
[24] C-S Poon L Lam S C Kou Y-L Wong and R WongldquoRate of pozzolanic reaction of metakaolin in high-performance cement pastesrdquo Cement and Concrete Re-search vol 31 no 9 pp 1301ndash1306 2001
[25] L Lam Y L Wong and C S Poon ldquoDegree of hydration andgelspace ratio of high-volume fly ashcement systemsrdquo Ce-ment and Concrete Research vol 30 no 5 pp 747ndash756 2000
[26] D Damidot B Lothenbach D Herfort and F P Glasserldquo+ermodynamics and cement sciencerdquo Cement and ConcreteResearch vol 41 no 7 pp 679ndash695 2011
Advances in Materials Science and Engineering 13
CorrosionInternational Journal of
Hindawiwwwhindawicom Volume 2018
Advances in
Materials Science and EngineeringHindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Journal of
Chemistry
Analytical ChemistryInternational Journal of
Hindawiwwwhindawicom Volume 2018
ScienticaHindawiwwwhindawicom Volume 2018
Polymer ScienceInternational Journal of
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Advances in Condensed Matter Physics
Hindawiwwwhindawicom Volume 2018
International Journal of
BiomaterialsHindawiwwwhindawicom
Journal ofEngineeringVolume 2018
Applied ChemistryJournal of
Hindawiwwwhindawicom Volume 2018
NanotechnologyHindawiwwwhindawicom Volume 2018
Journal of
Hindawiwwwhindawicom Volume 2018
High Energy PhysicsAdvances in
Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom
The Scientific World Journal
Volume 2018
TribologyAdvances in
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
ChemistryAdvances in
Hindawiwwwhindawicom Volume 2018
Advances inPhysical Chemistry
Hindawiwwwhindawicom Volume 2018
BioMed Research InternationalMaterials
Journal of
Hindawiwwwhindawicom Volume 2018
Na
nom
ate
ria
ls
Hindawiwwwhindawicom Volume 2018
Journal ofNanomaterials
Submit your manuscripts atwwwhindawicom
CorrosionInternational Journal of
Hindawiwwwhindawicom Volume 2018
Advances in
Materials Science and EngineeringHindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Journal of
Chemistry
Analytical ChemistryInternational Journal of
Hindawiwwwhindawicom Volume 2018
ScienticaHindawiwwwhindawicom Volume 2018
Polymer ScienceInternational Journal of
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Advances in Condensed Matter Physics
Hindawiwwwhindawicom Volume 2018
International Journal of
BiomaterialsHindawiwwwhindawicom
Journal ofEngineeringVolume 2018
Applied ChemistryJournal of
Hindawiwwwhindawicom Volume 2018
NanotechnologyHindawiwwwhindawicom Volume 2018
Journal of
Hindawiwwwhindawicom Volume 2018
High Energy PhysicsAdvances in
Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom
The Scientific World Journal
Volume 2018
TribologyAdvances in
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
ChemistryAdvances in
Hindawiwwwhindawicom Volume 2018
Advances inPhysical Chemistry
Hindawiwwwhindawicom Volume 2018
BioMed Research InternationalMaterials
Journal of
Hindawiwwwhindawicom Volume 2018
Na
nom
ate
ria
ls
Hindawiwwwhindawicom Volume 2018
Journal ofNanomaterials
Submit your manuscripts atwwwhindawicom
Top Related