Research ArticleDevelopment and Performance Test including Mechanical andThermal of New Tenon Composite Block Masonry Walls

Hui Su 1 Dongyue Wu 2 Mengying Shen3 Wei Chen2 and Shilin Wang2

1School of Architectural Engineering Jinling Institute of Technology Nanjing China2School of Civil Engineering and Architecture Jiangsu University of Science and Technology Zhenjiang China3Zhenjiang Archives Zhenjiang Jiangsu China

Correspondence should be addressed to Dongyue Wu dywujusteducn

Received 31 May 2019 Revised 19 August 2019 Accepted 24 August 2019 Published 22 September 2019

Academic Editor Giorgio Pia

Copyright copy 2019 Hui Su et al is is an open access article distributed under the Creative Commons Attribution License whichpermits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

To improve the thermal performance of external masonry walls a new tenon composite block is proposed as the externalmaintenance component which contains the internal hollow concrete block part the external block part and the extrudedpolystyrene layer fixed by tenons e production process and concrete material mixing ratio were optimized for the new tenoncomposite block to promote its application e mechanical strength and thermal properties of the optimized tenon compositeblocks were tested with experiments and numerical simulation in this studye testing and simulation results indicated that afterutilizing the two optimized concrete mixing ratios the tenon composite block strength matched the strength requirementsaccording to the related design code e thermal performance of the tenon composite block wall was also good compared withthat of a common block wall

1 Introduction

Large amount of energy consumption and CO2 emissionshave caused serious environmental damage in recent yearsdue to rapid urbanization Climate change and energy con-servation are seriously concerned As a result architecturalconcepts of ldquoecological citiesrdquo ldquogreen buildingsrdquo ldquobuildingenergy conservationrdquo and ldquolow-carbon buildingsrdquo have beengradually applied [1ndash3] Statistical data indicate that heatingventilation and air-conditioning systems for buildingscomprise approximately 50 of the building energy con-sumption and 20 of the total energy consumption in theUnited States [4 5] Table 1 shows the energy consumptionpercentage of different building parts including the air-conditioning illumination kitchen and water supply sys-tems and it can be seen that air-conditioning accounts formost of the energy consumption which is related to the airtemperature and the thermal performance of externalmaintenance components in a building Some relevant sta-tistical data also indicated that within the service age ofbuildings the heat loss through external protection or

structure components accounts for 70ndash80 of the total heatloss [3] and the heat loss through external walls accounts forapproximately 25 and 35 of the total heat loss duringwinter and summer respectively [6 7] us improving thethermal performance of building external walls is the key toreduce energy consumption in building service age

In traditional masonry walls fired clay brick has beenwidely used as a conventional masonry material for a longtime However this led to excessive consumption of clayenergy and resources and had a significant negative influ-ence on the environment [8] us recently new thermalinsulation wall materials are playing key role in improvingthe thermal performance of external walls and realisinggreen energy conservation in buildings New concretehollow blocks are effective replacements for traditional claybricks ey have simplified construction and reducedconstruction time as the thermal materials have been in-tegrated in the blocks and additional external thermalconstruction is not needed [9ndash12]

However in the development and application of newconcrete hollow blocks thermal performance and mechanical

HindawiAdvances in Materials Science and EngineeringVolume 2019 Article ID 5253946 11 pageshttpsdoiorg10115520195253946

performance are still limited e polystyrene material hasbeen proved as one of the most effective thermal insulationmaterials of which the thermal conductivity is only03W(mmiddotK) and very close to that of air [13] But the ap-plication of polystyrene when used as polystyrene layer in-tegrated in building walls may cause unreliable connectingbetween thermal insulation layer with the main block or wallpart and reduce the service age e application of metalfasteners including steel bars was able to fix the polystyrenethermal insulation layer but heat bridge caused by steel barswas very serious and reduced the total thermal performance[14ndash16] So the thermal performance and mechanical per-formance are still limited and need to be balanced in appli-cation when using polystyrene material in new hollow blocks

Based on the energy conservation requirements a newtenon composite block (TCB) is proposed as the externalmaintenance component in building as shown in Figure 1e TCB consists of the internal hollow concrete block partand the external block part which includes the concretedecoration layer at the block surface and the extrudedpolystyrene layer fixed by tenons between the internal hollowblock part and decoration layere staggered arrangement oftenons in the TCB improves the connecting strength betweenthe internal block and thermal insulation layer Moreover thestaggered arrangement tenon prevents the reduction of thethermal insulation thickness and ensures the stability of thethermal insulation performance is study focused on thestrength and thermal performance of the TCB By the opti-mization of concrete mixing ratio the strength testing onsingle TCB the thermal experimental test and the finiteelement simulation of TCB specimens the mechanical andthermal performance of TCB has been proved Figure 2 showsthe main contents and study procedure of this study

2 Tenon Composite Block

21 Initial Concrete Mixing Ratio of Block Material As thetenon composite block is produced by vibrating and pressingconcrete materials into specially manufactured steel moldthe concrete material needs good molding performance einitial concrete mixing ratio of TCB was determined basedon the experience obtained from early preproduction ofconcrete block molding manufacturing and casting con-ditions in the laboratory e initial concrete mixing ratio ofthe TCB was 20 gravel 20 stone powder 40 mediumsand 12 fly ash 7 water-reducing agent and 6 water

22 Block Manufacturing Mold e traditional blockmolding approach includes two steps (1) the molding of theinternal block part which is used to bear loads and wascompletely made of concrete (2) the connecting between theinternal block part and the external heat insulation part e

traditional molding approach is complicated due to the twoseparated steps and leads to unreliable connection perfor-mance between the internal block part and the external heatinsulation part which may cause service lifetime reductiondue to temperature stresses between internal and externalblock parts To avoid the service lifetime reduction caused bythe traditional block molding approach this study applied anewmolding approache new one-stepmolding approachonly contains onemolding step according to the block shapesize and experimental manufacturing condition e moldfor the new one-step block manufacturing is shown inFigure 3

Table 1 Energy consumption percentage of different buildingparts

Energy category Air condition Illumination Kitchen Watersupply

Proportion 65 14 6 15

390

35 50 35

300

195

6515

15

25

Internal hollow concrete block part

Extruded polystyrene layer

External block part

35 R25

45deg

Figure 1 e tenon composite block (mm)

Research aim invite new concrete hollow blocks with reliable thermal and mechanical performance

to satisfy energy conservation requirements

The new tenon composite block (TCB)

Optimization on new TCB manufacture

Mixing ratioof materials

Manufacturingmold

Manufacturingprocess

Thermal and mechanical performance

Experimental test for thermal performance

Experimental test for mechanical

performance

Finite element simulation test for thermal performance

Background and early achievement

Figure 2 Main contents and study procedure of this study

2 Advances in Materials Science and Engineering

23 Optimized Mixing Ratio of TCB Concrete In earlyconcrete production for new TCB one problem was foundthat the fine stone with 5mmndash16mm diameter has anundesirable influence on concrete properties because itcombines with water and cement to form large mud blockand hinders the hydration reaction [9] To avoid thedamaging influence from fine stone with large diametermechanical basalt sand with a diameter of 2mmndash5mmwhich also has a lower thermal conductivity than traditionallimestone was applied as coarse aggregates to optimize theconcrete properties and thermal performance

By using the mechanical basalt sand the mixing ratio ofraw materials needs to be verified To optimize the materialsmixing ratio the following measures were adopted

(1) More water was needed because the mechanicalstone is rough with more sharp edges and has lowgradation properties which may influence theconcrete strength and mechanical properties estone powder was added into the concrete mixingratio to fill the gaps between concrete aggregates andto improve the compactness and strength of con-crete To achieve better thermal performancelimestone powder was the final selection

(2) Ceramsite is a lightweight aggregate produced byfoaming in a rotary kiln and has spherical shapesmooth and hard surface low density low thermalconductivity and high strength It was added to the

mixing ratio of rawmaterials to optimize the thermaland mechanical properties of concrete Additionallyto avoid forming large blocks of mud the diameter ofthe ceramsite particles was controlled to be lowerthan 5mm

(3) e content of fly ash was increased to improve theconcrete strength durability thermal properties andwater absorption properties and to generateldquobridgesrdquo and cavities inside the concrete material toreduce the thermal conductivity [17]

According to the above measures two mixing ratios of Aand B were designed which differ from the mechanical sandand stone powder proportions e A and B mixing ratiosare shown in Table 2 e actual performance of the twomixing ratios was evaluated in the following mechanical andthermal tests

24 Manufacturing Process e manufacturing processprocedure is shown in Figure 4 After the blockmanufacturing equipment was placed in correct positionthe extruded polystyrene heat insulation layer can be placedinto the block mold after lubricant was brushed on moldsidewalls as shown in Figure 5

e concrete production process contains two steps thefirst step is a 20-second premixing step in a vertical materialmixer to prepare uniform mixture of concrete raw materials

1

2

3

45

6

(a)

7

8

(b)

9

(c)

10

(d)

Figure 3 Block manufacturing equipment (1) Upper hydraulic jack (2) upper mold plate (3) blockmold (4) supporting screw (5) base hydraulicjack (6) base fixing plate (7) extruded polystyrene layer (8) movable side plate of blockmold (9) uppermold plate (10) block locating plate (a)ewhole block manufacturing system (b) Details of the block mold (c) Details of the upper block plate (d) Details of the block support plate

Advances in Materials Science and Engineering 3

which consists of cement stone powder fly ash and water-reducing agent according to the mixing ratio the coarseaggregate and water are not included in this stepe secondstep consists of stirring for 1minute with 12 of the requiredwater and at least 2minutes of stirring after the addition ofall the remaining coarse aggregate and water

After the prepared hard concrete was added into theblock cast mold the block was formed with the pressuregenerated by the microcomputer-controlled electrohy-draulic servo-loading system as shown in Figure 6 Fol-lowing the block formation the block can be easily releasedby lifting the upper hydraulic jack as shown in Figure 7

e block products are shown in Figure 8 e curingprocess for all blocks was in the natural environment wherethe blocks were covered with straw and watered for the first14 days after the blocks were released A TCB after 28 days ofstandard curing is shown in Figure 9

3 Strength Test

Ten blocks from each mixing ratio (A and B) were randomlyselected and divided into two groups to test the strengthEach group contained five blocks from every mixing ratioOne group (5 from A and 5 from B) was tested after blockproduction e blocks in the other group (5 from A and 5from B) were tested after being placed for 6months in open-air conditions e strength tests used a WAW-1000 elec-trohydraulic servo-testing machine e loading speed wascontrolled to be 02ndash03MPas and the loading continueduntil a vertical crack appeared on the block according toldquoTest Methods for the Concrete Block and Brickrdquo [18]Limited by experimental conditions of the WAW-1000electrohydraulic servo-testing machine the effect of porosityand eccentricity were not considered in the strength testeaverage compressive strengths are shown in Table 3

e average compressive strength for each case is shownin Table 3 Effect of porosity and eccentricity on the me-chanical properties can be found e strength requirementof 5MPa [19] was exceeded for each case meaning that thethree concrete mixing ratios can be applied to blocks used asinfill walls and load-bearing walls in multilayer masonrystructures As in the block manufacturing process the po-rosity was mainly controlled in the materials stirring and

Table 2 Optimized A and B mixing ratios ()

Cement Gravel (mechanical sand) Stone powder Ceramsite Medium sand Fly ash Water-reducing agent WaterInitial ratio 20 20 33 12 7 2 6Mixing ratio A 18 25 18 8 10 10 2 9Mixing ratio B 18 18 25 8 10 10 2 9

Cleaning and fixing block equipment

Preparing

Materials mixing stepRequirements 1-minute stirring for raw materials with half required water and at

least 2 minutes of stirring with all remaining coarse aggregate and water

Achievement finished concrete material

Concrete production processEquipment vertical material mixer

Premixing step Requirements all raw materials except

coarse aggregate and water mixing for 20 seconds

Achievement uniform mixture of materials

Block production processEquipment cast mold electrohydraulic

servo-loading system

Block casting and forming Requirements the block was formed in the block cast mold with the pressure generated

by the microcomputer-controlled electrohydraulic servo-loading system

Achievement complete block

Block releasing and curing Requirement block is released by hydraulic jack and cured for 28 days standard curing

Achievement to release the block out of mold and generate block strength

Figure 4 Manufacturing process of the new TCB

Figure 5 e extruded polystyrene heat insulation layer locationin the mold

4 Advances in Materials Science and Engineering

block casting step in the manufacturing process the testingstrength of TCB matched the strength requirements ofdesign codes proving that the porosity was well controlled inthe manufacturing process

e compressive strength of mixing ratio A is less than5 that of mixing ratio B e main difference between

mixing ratio A and B is the portion of mechanical sand andstone powder e mechanical sand percentage in mixingratio A is higher but as a coarse aggregate mechanical sandimproved the strength and reduced the thermal insulationperformanceerefore the thermal insulation performanceof mixing ratios A and B is discussed below in Section 3together with mechanical performance

Blocks with the A and B mixing ratios with open-airplacing for 6months after manufacture have 77 and 41higher in average compressive strengths respectively thanthe A and Bmixing ratio blocks after productionis meansthe chemical reaction of material components continued toincrease the strength with time Finally the TCB with theinitial concrete mixing ratio had the highest strength of 815MPa compared to that of ratios A and B meaning that theoptimization of the thermal performance caused a reductionin the block compressive strength

4 Thermal Testing

41 -ermal Testing Apparatus and Specimens e WTRZ-1212 steady-state heat transfer performance testing machinewas used for this test which was developed and producedstrictly according to the requirements in the national teststandard of ldquoBuilding Element-Determination of Steady-State

(a) (b)

Figure 6 Blocks being formed (a) Concrete being prepared (b) Pressure being applied by a hydraulic jack

Figure 7 Upper hydraulic jack being lifted to release the block

Figure 8 Blocks being cured

Figure 9 Block after the curing process

Advances in Materials Science and Engineering 5

ermal Transmission PropertiesmdashCalibrated and GuardedHot Boxrdquo (GBT13475-2008) in China [17] e maximumsample size for standard WTRZ-1212 is 164mtimes 164m andthe measuring size of the TCB wall specimen is 12mtimes 12me testingmachine is shown in Figure 10e test is based onthe guarding hot-box method which relies on a heat pro-tective box to balance external and internal environments andquantitatively analyze thermal performance with minimizedheat consumption and high accuracy e box is also opti-mized to reduce error by synthetically measuring the heat lossof test instruments e testing machine and specimen inreality are shown in Figure 11

ree TCB wall specimens were tested to compare thethermal performance using different concrete mix pro-portions initial mixing ratio and the A and B mixing ratiose block and wall parameters are shown in Table 4 Table 5shows the initial parameters used for the thermal test

42 -ermal Test Results e three TCB wall specimenswere tested strictly according to the national test standard ofldquoBuilding Element-Determination of Steady-State ermalTransmission PropertiesmdashCalibrated and Guarded HotBoxrdquo (GBT13475-2008) [17] In the test the heating powerQp of the heating machine shown in Figure 12 will becollected Apart from that the temperature difference θ3between the inner wall and the outer wall of shelter inheating part (Figure 12) the hot surface temperature Tsi andthe cool surface temperature Tse of the specimen the airtemperature of protective hot box Tni and the air temper-atures of cool box Tne will be collected among which the Tniand Tne were set to be 30degC and minus 10degC in the test but werestill collected to consider testing errors and to improvetesting accuracy e thermal parameters of the three blockwall specimens can be calculated from the collected data andaccording to equations (1)mdash(5) shown in Table 6 includingthe thermal resistance the thermal conductivity the heattransfer coefficient and the total thermal resistance

Q1 QP minus M3θ3 (1)

R A Tsi minus Tse( 1113857

Q1 (2)

λk δR

(3)

K Q1

A Tni minus Tne( 11138571113858 1113859 (4)

Rsu 1K

(5)

From the thermal parameters in Table 6 the followingconclusions can be drawn

(1) e TCB specimens have good total thermal per-formance when compared the total thermal re-sistance Rsu to the Rsu value of 30m2 middot KW ofcommon block wall in which the block has threerows of heat isolation holes and size of390mmtimes 190mmtimes 190mm e Rsu values of theTCB wall are 610 650 and 670 times of the totalthermal resistance of common block wall for the Q-1the Q-2 and the Q-3 respectively

(2) According to the total thermal resistance Rsu valuesof the three wall specimens of Q-1 Q-2 and Q-3 theheat insulation properties of the TCB walls withmixing ratios A and B are 656 and 984 higherthan that of specimen with the initial mixing ratiorespectively which indicates that the mixing ratioand production processing optimization have im-proved thermal performance As this study con-cluded in Section 2 that the TCB with the initialconcrete mixing ratio had the highest strength of815MPa compared to that of ratios A and B to-gether with the Rsu values differences between Q-1 toQ-2 and Q-3 it can be proved that by the optimi-zation of concrete mixing ratio the thermal per-formance was improved and the block compressivestrength was reduced Based on the above conclu-sions it is suggested that the two optimized mixingratios and block production process should be usedin TCB production

(3) e total thermal resistance Rsu of the block wall withthe mixing ratio A (Q-2) is 308 lower than that ofthe block wall with mixing ration B (Q-3) meaningthat the heat isolation properties of the mixing ratioA wall are better than that of the mixing ratio B wallAccording to the block compressive strength shownin Table 3 and the results in Section 2 the com-pressive strength of mixing ratio A is less than 5that of mixing ratio B Together with thermal pa-rameters in Table 6 it can be insufficiently provedthat the portion of mechanical sand and stonepowder is the key to control thermal insulation andmechanical performance more mechanical sand canimprove the strength and more stone powder canimprove the thermal insulation performance Butwhen considering there is a difference of 308 inRsubetween the A and B mixing ratios however thetrend is not obvious when considering the 7 dif-ference in the mechanical sand and stone powderpercentages in the A and B mixing ratios e in-fluence of mechanical sand and limestone powder

Table 3 Average compressive strength of blocks (MPa)

Mixing ratio A B A (6months in open air) B (6months in open air) Initial mixing ratioCompressive strength 688 657 741 684 815

6 Advances in Materials Science and Engineering

percentage should be further evaluated based onmore test cases

5 Finite Element Simulation

51 Finite Element Model e thermal analysis module in-tegrated in ANSYS finite element simulation software wasused to simulate the thermal performance of the TCB wall inheated steady state In the thermal simulation of wall

specimen in this study as the wall size is 12mtimes 12mtimes 02mof which the specimen front face sizes are much larger thanthe specimen thickness the heat energy flow simulation willbe simplified to be one-dimensional heat conduction simu-lation on the two-dimensional finite element model whichonly considers the heat energy flow in the thickness directionAnd as the thermal experimental testing was the steady-stateheat transfer performance testing the finite element simu-lation will also assume that the specimen was in steady-stateheat transfer situation Finally the finite element simulationadopted the following three assumptions

(1) Different material parts in TCB including the internalhollow concrete block part the extruded polystyrenelayer and the external block part will be assumed tobe inseparable connected and no material or thermalproperties changes with temperature

(2) e heat energy flow will only be in the thicknessdirection and the simulation will be simplified to beone-dimensional heat conduction simulation

(3) e simulation of the specimen is in the steady-stateheat transfer situation which means the environ-ment temperature of the two sides of the specimenremains constant

Based on the above assumptions and test method[20ndash22] the simulation element for the TCB wall wasselected as PLANE55 which is a two-dimensional thermalsolid element with 4 nodes and can be used as a planar oraxisymmetric element in two-dimensional heat steady-stage and instantaneous-stage analyses [23] e node inthe PLANE55 element only contains one temperaturedegree of freedom

52 Material Properties According to the experimental testresults and the theory of the parallel-series method inequations (1)mdash(5) the thermal conductivity of the concretefor mixing ratio A can be calculated as λk 1178W(mmiddotK)Other thermophysical parameters of related materials usedin the TCB are determined according to the testing standardof ldquoCode for ermal Design of Civil Buildingrdquo (GB 50176-2016) [24] and are shown in Table 7

53 Meshing and Boundary Conditions e finite elementgeometric model was automatically generated by the ANSYS

Specimen frame

ShelterHeating machine

Heat conduction screen

Heat circulating fan

Heat circulating pipeline

Cooling pipeline

Specimen

Cooling screen

Cooling fan

Cooler

Cooling machine

Figure 10 Schematic of the test machine for the joggled joint block wall thermal test

Figure 11 Testing machine in reality

Table 4 Specimen parameters

Specimen Block Size (mm)Q-1 Initial mixing ratio block 390times 300times115Q-2 A mixing ratio block 390times 300times115Q-3 B mixing ratio block 390times 300times115

Table 5 Initial parameters used for the thermal test

Air temperature of experimental heat box 300degCAir temperature of protective hot box 300degCAir temperature of cold box minus 100degCRelative humidity of experimental heat box 30Heat flux coefficient M3 of the external wall ofmeasuring heat box 152WK

Wall thickness 300mm

Advances in Materials Science and Engineering 7

simulation software and the mesh was discretized into atriangle or quadrilateral shape with 5mm mesh sizeCompared with the thermal experimental test results of thewall the interior temperature of the simulated wall was 30degCand the exterior temperature of the wall was minus 10degC efinite element simulation model assumed that the boundaryconditions are complete heat isolation the convective heattransfer is only applied on internal and external surfaceswhich are selected as boundary condition while no heattransfer exists on block connection joints e convectiveheat transfer coefficients of the interior and exterior were87W(m2 middotK) and 230 W(m2 middotK) respectively e sim-plified one-dimensional TCB wall model is shown in Fig-ure 12 e ANSYS geometric model is shown in Figure 13e mesh used for the joggled joint block wall model isshown in Figure 14

54 Simulation Results e finite element simulation cal-culated the temperature distribution and heat flux distribu-tion maps shown in Figures 15 and 16 According to the heatflux distribution map the average heat flux density Q1 can beobtained by ANSYS software And according to Fourierrsquos lawof heat conduction in equation (2) the thermal conductivityvalue can be obtained e relation between specimen totalthermal resistance and thermal conductivity can be obtainedby equation (3)e average thermal performance parametersof the wall specimen are shown in Table 8 By comparing thecalculation results with those obtained in the previous ex-perimental test it can be found that the numerical simulation

thermal resistance of the A mixing ratio block wall is2133(m2 middotK)W which is 61 higher than that obtainedfrom experimental testing of 1950(m2 middotK)W e relativeerror is caused by two reasons (1) the simulation modelassumes that the boundary conditions are complete heatisolation and inconsistent with reality (2) heat loss andmeasurement error are inevitable in the experimental testprocess Comparing the simulation results with the experi-mental results the relative error is low and acceptable

Figure 15 shows the temperature distribution of the TCBwall where it can be seen that the temperature decreasesgradually from the internal surface to the external surfaceHowever the area with the most rapid temperature decreasewas the heat isolation layer Because temperature variationrate is inversely proportional to the thermal conductivityvalue of the material and the thermal conductivity value ofthe extruded polystyrene layer is 0030W(mmiddotK) which is farless than the value of 1178W(mmiddotK) for concrete and0746W(mmiddotK) for air it can be proved that the extrudedpolystyrene layer contributes most of the heat isolationperformance It can be found in Figure 15 that the tem-perature boundary lines of 21degC and 25degC exhibited obviousfluctuations there was a high temperature distribution areain the middle position of block while low temperaturedistribution area is close to the block joint proving theexistence of thermal bridge caused by the block jointsHowever because the main heat isolation component is theextruded polystyrene layer the fluctuate depth of temper-ature was limited in the concrete part and no temperatureinfluence reached at the external surface

Tenon composite block Mortar joint

5 390 390 51010

1200

30degC interior temperature

ndash10degC interior temperature

300

390

Figure 12 Simplified heat transfer model of the block wall

Table 6 ermal parameters of test specimens

Specimen ermal resistanceR(m2 middotKW)

ermal conductivityλk (W(mmiddotK))

Heat transfer coefficientK (W(m2 middotK))

Total thermal resistanceRsu(m2 middotKW)

Q-1 1581 0632 0546 1830Q-2 1691 0591 0513 1950Q-3 1765 0567 0497 2010

Table 7 ermophysical parameters of materials in TCB

Material ermal conductivity (W(mmiddotK)) ickness (mm)Concrete 1178 195Extruded polystyrene layer 0030 65Vertical air interlayer 0746 135Masonry mortar 0930 25

8 Advances in Materials Science and Engineering

Figure 16 is the heat flux density distribution of thetenon connected block wall model in heat steady stage eheat flux density in most of the wall area is very low in-cluding the internal hollow concrete part the extrudedpolystyrene layer and the external concrete part whichindicated that the extruded polystyrene layer and the airinsulation layer effectively prevent heat transmissionHowever a very high heat flux density distributed at theblock joints which proved the same phenomenon of thethermal bridge in Figure 15

Concluding the temperature and heat flux density dis-tribution in Figures 15 and 16 the extruded polystyrenelayer contributed very reliable and continuous thermal

insulation performance which contributed to the staggeredarranged tenon avoiding the thickness reduction of extrudedpolystyrene layer is also proved the reasonability of thestaggered arranged tenon in this new TCB Apart from thereasonably arranged tenon the block joint still inevitablybecomes the heat bridge of tenon composite thermalinsulation wall and further study on avoiding heat bridge ofblock joint should be focused

6 Conclusion

e main conclusions obtained from the experimentaltesting and numerical simulation are as follows

Figure 13 Geometric model of the thermal analysis unit

Figure 14 Grid diagram of the thermal analysis unit

ndash10 ndash111111 777778 166667 25555630211111122222333333ndash555556

Figure 15 Cloud pattern of wall temperature distribution

122015 808705 160521 240171 319822410453 120696 200346 279997 359647

Figure 16 Distribution of heat flux density in the wall

Table 8 Total thermal resistance of the block wall in the experimental test and numerical simulation

Condition Total thermal resistance Ru (m2 middotK)W Relevant error

Experiment 2010 61Numerical simulation 2133

Advances in Materials Science and Engineering 9

(1) e experimental strength test of the blocks with threedifferent mixing ratios which were proposed by earlyexperimental test experiences and optimizationproved that the mixing ratios were reliable to supplyhigher strength than the design code required strength

(2) e experimental steady-state thermal test on TCBwall specimens indicated that the TCB wall specimenhas good thermal performance when compared tothe total thermal resistance with the common blockwall

(3) Experimental results from the thermal test and themechanical test proved that the A mixing ratio blockhad better thermal performance which contributesto the mechanical sand and stone powder percent-ages while very close strength to that of B mixingratio block erefore it is suggested that the opti-mized A mixing ratio can be used in the TCBproduction

(4) e numerical simulation provided acceptable andaccurate results with a low relative error e nu-merical simulation results proved the reasonabilityof the staggered arranged tenon to avoid thermalperformance reduction But the inevitable thermalbridge existed at the block joints and should befocused in further study

Nomenclature

Basic UnitsK Kelvin temperatureMPa Mega Pascalm Metermm MillimeterW Watts SeconddegC Celsius temperatureLatin and Greek lettersA Face area of specimen (m2)

K Heat transfer coefficient (W(m2 middotK))

M3 Heat flux coefficient of external wall of measuring heatbox (WK)

Q1 Heat flux rate (W)

R ermal resistance (m2 middotKW)

Rsu Total thermal resistance (m2 middotKW)

δ Specimen thickness (m)

λk ermal conductivity (W(mmiddotK))

AcronymsCO2 Carbon dioxideTCB Tenon composite block

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

is work was supported by the Science Project of JiangsuWater Conservancy Bureau (Grant no 2016038) the SocialDevelopment Project of Nanjing Science and TechnologyCommission Fund Programs (Grant no 201505018) and theNational Natural Science Foundation for Young Scientists ofChina (Grant no 51708260)

References

[1] A N Raut and C P Gomez ldquoAssessment of thermal andenergy performance of thermally efficient sustainable wallsystem for Malaysian low cost housingrdquo Applied -ermalEngineering vol 136 pp 309ndash318 2018

[2] G Vasconcelos P Lourenco P Mendonca et al ldquoProposal ofan innovative solution for partition walls mechanical ther-mal and acoustic validationrdquo Construction and BuildingMaterials vol 48 pp 961ndash979 2013

[3] R D Diao L Z Sun and F Yang ldquoermal performance ofbuilding wall materials in villages and towns in hot summerand cold winter zone in Chinardquo Applied-ermal Engineeringvol 128 pp 517ndash530 2018

[4] V Echarri-Iribarren C Rizo-Maestre and F Echarri-Iri-barren ldquoHealthy climate and energy savings using thermalceramic panels and solar thermal panels in mediterraneanhousing blocksrdquo Energies vol 11 no 10 2018

[5] M Fogiatto G Santos and J Catelan ldquoNumerical two-di-mensional steady-state evaluation of the thermal trans-mittance reduction in hollow blocksrdquo Energies vol 12 no 3p 449 2019

[6] E Wati P Meukam and J C Damfeu ldquoModeling thermalperformance of exterior walls retrofitted from insulation andmodified laterite based bricks materialsrdquo Heat and MassTransfer vol 53 no 12 pp 3487ndash3499 2017

[7] A Laaouatni N Martaj R Bennacer M Lachi M El Omariand M El Ganaoui ldquoermal building control using activeventilated block integrating phase change materialrdquo Energyand Buildings vol 187 pp 50ndash63 2019

[8] J Wu G L Bai P Wang and Y Liu ldquoMechanical propertiesof a new type of block made from shale and coal ganguerdquoConstruction and Building Materials vol 190 pp 796ndash8042018

[9] M X Xiong Y H Wang and J Y R Liew ldquoEvaluation onthermal behaviour of concrete-filled steel tubular columnsbased on modified finite difference methodrdquo Advances inStructural Engineering vol 19 no 5 pp 746ndash761 2016

[10] D Y Wu S T Liang M Y Shen Z X Guo X J Zhu andC F Sun ldquoExperimental estimation of seismic properties ofnew precast shear wall spatial structure modelrdquo EngineeringStructures vol 183 pp 319ndash339 2019

[11] D Y Wu S T Liang M Y Shen et al ldquoFinite-elementsimulation on NPGCS precast shear wall spatial structuremodelrdquo Advances in Civil Engineering vol 2019 Article ID2647891 17 pages 2019

[12] S Noor-E-Khuda and F Albermani ldquoMechanical propertiesof clay masonry units destructive and ultrasonic testingrdquoConstruction and Building Materials vol 219 pp 111ndash1202019

[13] I Gnip S Vejelis and S Vaitkus ldquoermal conductivity ofexpanded polystyrene (EPS) at 10 degrees C and its con-version to temperatures within interval from 0 to 50 degreesCrdquo Energy and Buildings vol 52 pp 107ndash111 2012

10 Advances in Materials Science and Engineering

[14] T eodosiou K Tsikaloudaki S Tsoka and P Chastasldquoermal bridging problems on advanced cladding systemsand smart building facadesrdquo Journal of Cleaner Productionvol 214 pp 62ndash69 2019

[15] P Brzyski M Grudzinska and D Majerek ldquoAnalysis of theoccurrence of thermal bridges in several variants of con-nections of the wall and the ground floor in constructionTechnology with the use of a hemp-lime compositerdquo Mate-rials vol 12 no 15 2019

[16] M Khoukhi ldquoe combined effect of heat and moisturetransfer dependent thermal conductivity of polystyreneinsulation material impact on building energy performancerdquoEnergy and Buildings vol 169 pp 228ndash235 2018

[17] GBT13475-2008 Building Element-Determination of Steady-State -ermal Transmission PropertiesndashCalibrated andGuarded Hot Box China Architecture amp Building PressBeijing China 2008

[18] GBT4111-2013 Test Methods for the Concrete Block andBrick China Architecture amp Building Press Beijing China2013

[19] GB50003-2011 Code for Design of Masonry Structures ChinaArchitecture amp Building Press Beijing China 2011

[20] H Yang X Xu W Xu and I Neumann ldquoTerrestrial laserscanning-based deformation analysis for arch and beamstructuresrdquo IEEE Sensors Journal vol 17 no 14 pp 4605ndash4611 2017

[21] H Yang X Xu and I Neumann ldquoDeformation behavioranalysis of composite structures under monotonic loads basedon terrestrial laser scanning Technologyrdquo Composite Struc-tures vol 183 pp 594ndash599 2017

[22] H Yang X Xu and I Neumann ldquoLaser scanning-basedupdating of a finite-element model for structural healthmonitoringrdquo IEEE Sensors Journal vol 16 no 7 pp 2100ndash2104 2016

[23] V Koci J Koci J Madera et al ldquoermal and hygric as-sessment of an inside-insulated brick wall 2D critical ex-periment and computational analysisrdquo Journal of BuildingPhysics vol 41 no 6 pp 497ndash520 2018

[24] GB 50176-2016 Code for -ermal Design of Civil BuildingChina Architecture amp Building Press Beijing China 2016

Advances in Materials Science and Engineering 11

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

23 Optimized Mixing Ratio of TCB Concrete In earlyconcrete production for new TCB one problem was foundthat the fine stone with 5mmndash16mm diameter has anundesirable influence on concrete properties because itcombines with water and cement to form large mud blockand hinders the hydration reaction [9] To avoid thedamaging influence from fine stone with large diametermechanical basalt sand with a diameter of 2mmndash5mmwhich also has a lower thermal conductivity than traditionallimestone was applied as coarse aggregates to optimize theconcrete properties and thermal performance

By using the mechanical basalt sand the mixing ratio ofraw materials needs to be verified To optimize the materialsmixing ratio the following measures were adopted

(1) More water was needed because the mechanicalstone is rough with more sharp edges and has lowgradation properties which may influence theconcrete strength and mechanical properties estone powder was added into the concrete mixingratio to fill the gaps between concrete aggregates andto improve the compactness and strength of con-crete To achieve better thermal performancelimestone powder was the final selection

(2) Ceramsite is a lightweight aggregate produced byfoaming in a rotary kiln and has spherical shapesmooth and hard surface low density low thermalconductivity and high strength It was added to the

mixing ratio of rawmaterials to optimize the thermaland mechanical properties of concrete Additionallyto avoid forming large blocks of mud the diameter ofthe ceramsite particles was controlled to be lowerthan 5mm

(3) e content of fly ash was increased to improve theconcrete strength durability thermal properties andwater absorption properties and to generateldquobridgesrdquo and cavities inside the concrete material toreduce the thermal conductivity [17]

According to the above measures two mixing ratios of Aand B were designed which differ from the mechanical sandand stone powder proportions e A and B mixing ratiosare shown in Table 2 e actual performance of the twomixing ratios was evaluated in the following mechanical andthermal tests

24 Manufacturing Process e manufacturing processprocedure is shown in Figure 4 After the blockmanufacturing equipment was placed in correct positionthe extruded polystyrene heat insulation layer can be placedinto the block mold after lubricant was brushed on moldsidewalls as shown in Figure 5

e concrete production process contains two steps thefirst step is a 20-second premixing step in a vertical materialmixer to prepare uniform mixture of concrete raw materials

1

2

3

45

6

(a)

7

8

(b)

9

(c)

10

(d)

Figure 3 Block manufacturing equipment (1) Upper hydraulic jack (2) upper mold plate (3) blockmold (4) supporting screw (5) base hydraulicjack (6) base fixing plate (7) extruded polystyrene layer (8) movable side plate of blockmold (9) uppermold plate (10) block locating plate (a)ewhole block manufacturing system (b) Details of the block mold (c) Details of the upper block plate (d) Details of the block support plate

Advances in Materials Science and Engineering 3

which consists of cement stone powder fly ash and water-reducing agent according to the mixing ratio the coarseaggregate and water are not included in this stepe secondstep consists of stirring for 1minute with 12 of the requiredwater and at least 2minutes of stirring after the addition ofall the remaining coarse aggregate and water

After the prepared hard concrete was added into theblock cast mold the block was formed with the pressuregenerated by the microcomputer-controlled electrohy-draulic servo-loading system as shown in Figure 6 Fol-lowing the block formation the block can be easily releasedby lifting the upper hydraulic jack as shown in Figure 7

e block products are shown in Figure 8 e curingprocess for all blocks was in the natural environment wherethe blocks were covered with straw and watered for the first14 days after the blocks were released A TCB after 28 days ofstandard curing is shown in Figure 9

3 Strength Test

Ten blocks from each mixing ratio (A and B) were randomlyselected and divided into two groups to test the strengthEach group contained five blocks from every mixing ratioOne group (5 from A and 5 from B) was tested after blockproduction e blocks in the other group (5 from A and 5from B) were tested after being placed for 6months in open-air conditions e strength tests used a WAW-1000 elec-trohydraulic servo-testing machine e loading speed wascontrolled to be 02ndash03MPas and the loading continueduntil a vertical crack appeared on the block according toldquoTest Methods for the Concrete Block and Brickrdquo [18]Limited by experimental conditions of the WAW-1000electrohydraulic servo-testing machine the effect of porosityand eccentricity were not considered in the strength testeaverage compressive strengths are shown in Table 3

e average compressive strength for each case is shownin Table 3 Effect of porosity and eccentricity on the me-chanical properties can be found e strength requirementof 5MPa [19] was exceeded for each case meaning that thethree concrete mixing ratios can be applied to blocks used asinfill walls and load-bearing walls in multilayer masonrystructures As in the block manufacturing process the po-rosity was mainly controlled in the materials stirring and

Table 2 Optimized A and B mixing ratios ()

Cement Gravel (mechanical sand) Stone powder Ceramsite Medium sand Fly ash Water-reducing agent WaterInitial ratio 20 20 33 12 7 2 6Mixing ratio A 18 25 18 8 10 10 2 9Mixing ratio B 18 18 25 8 10 10 2 9

Cleaning and fixing block equipment

Preparing

Materials mixing stepRequirements 1-minute stirring for raw materials with half required water and at

least 2 minutes of stirring with all remaining coarse aggregate and water

Achievement finished concrete material

Concrete production processEquipment vertical material mixer

Premixing step Requirements all raw materials except

coarse aggregate and water mixing for 20 seconds

Achievement uniform mixture of materials

Block production processEquipment cast mold electrohydraulic

servo-loading system

Block casting and forming Requirements the block was formed in the block cast mold with the pressure generated

by the microcomputer-controlled electrohydraulic servo-loading system

Achievement complete block

Block releasing and curing Requirement block is released by hydraulic jack and cured for 28 days standard curing

Achievement to release the block out of mold and generate block strength

Figure 4 Manufacturing process of the new TCB

Figure 5 e extruded polystyrene heat insulation layer locationin the mold

4 Advances in Materials Science and Engineering

block casting step in the manufacturing process the testingstrength of TCB matched the strength requirements ofdesign codes proving that the porosity was well controlled inthe manufacturing process

e compressive strength of mixing ratio A is less than5 that of mixing ratio B e main difference between

mixing ratio A and B is the portion of mechanical sand andstone powder e mechanical sand percentage in mixingratio A is higher but as a coarse aggregate mechanical sandimproved the strength and reduced the thermal insulationperformanceerefore the thermal insulation performanceof mixing ratios A and B is discussed below in Section 3together with mechanical performance

Blocks with the A and B mixing ratios with open-airplacing for 6months after manufacture have 77 and 41higher in average compressive strengths respectively thanthe A and Bmixing ratio blocks after productionis meansthe chemical reaction of material components continued toincrease the strength with time Finally the TCB with theinitial concrete mixing ratio had the highest strength of 815MPa compared to that of ratios A and B meaning that theoptimization of the thermal performance caused a reductionin the block compressive strength

4 Thermal Testing

41 -ermal Testing Apparatus and Specimens e WTRZ-1212 steady-state heat transfer performance testing machinewas used for this test which was developed and producedstrictly according to the requirements in the national teststandard of ldquoBuilding Element-Determination of Steady-State

(a) (b)

Figure 6 Blocks being formed (a) Concrete being prepared (b) Pressure being applied by a hydraulic jack

Figure 7 Upper hydraulic jack being lifted to release the block

Figure 8 Blocks being cured

Figure 9 Block after the curing process

Advances in Materials Science and Engineering 5

ermal Transmission PropertiesmdashCalibrated and GuardedHot Boxrdquo (GBT13475-2008) in China [17] e maximumsample size for standard WTRZ-1212 is 164mtimes 164m andthe measuring size of the TCB wall specimen is 12mtimes 12me testingmachine is shown in Figure 10e test is based onthe guarding hot-box method which relies on a heat pro-tective box to balance external and internal environments andquantitatively analyze thermal performance with minimizedheat consumption and high accuracy e box is also opti-mized to reduce error by synthetically measuring the heat lossof test instruments e testing machine and specimen inreality are shown in Figure 11

ree TCB wall specimens were tested to compare thethermal performance using different concrete mix pro-portions initial mixing ratio and the A and B mixing ratiose block and wall parameters are shown in Table 4 Table 5shows the initial parameters used for the thermal test

42 -ermal Test Results e three TCB wall specimenswere tested strictly according to the national test standard ofldquoBuilding Element-Determination of Steady-State ermalTransmission PropertiesmdashCalibrated and Guarded HotBoxrdquo (GBT13475-2008) [17] In the test the heating powerQp of the heating machine shown in Figure 12 will becollected Apart from that the temperature difference θ3between the inner wall and the outer wall of shelter inheating part (Figure 12) the hot surface temperature Tsi andthe cool surface temperature Tse of the specimen the airtemperature of protective hot box Tni and the air temper-atures of cool box Tne will be collected among which the Tniand Tne were set to be 30degC and minus 10degC in the test but werestill collected to consider testing errors and to improvetesting accuracy e thermal parameters of the three blockwall specimens can be calculated from the collected data andaccording to equations (1)mdash(5) shown in Table 6 includingthe thermal resistance the thermal conductivity the heattransfer coefficient and the total thermal resistance

Q1 QP minus M3θ3 (1)

R A Tsi minus Tse( 1113857

Q1 (2)

λk δR

(3)

K Q1

A Tni minus Tne( 11138571113858 1113859 (4)

Rsu 1K

(5)

From the thermal parameters in Table 6 the followingconclusions can be drawn

(1) e TCB specimens have good total thermal per-formance when compared the total thermal re-sistance Rsu to the Rsu value of 30m2 middot KW ofcommon block wall in which the block has threerows of heat isolation holes and size of390mmtimes 190mmtimes 190mm e Rsu values of theTCB wall are 610 650 and 670 times of the totalthermal resistance of common block wall for the Q-1the Q-2 and the Q-3 respectively

(2) According to the total thermal resistance Rsu valuesof the three wall specimens of Q-1 Q-2 and Q-3 theheat insulation properties of the TCB walls withmixing ratios A and B are 656 and 984 higherthan that of specimen with the initial mixing ratiorespectively which indicates that the mixing ratioand production processing optimization have im-proved thermal performance As this study con-cluded in Section 2 that the TCB with the initialconcrete mixing ratio had the highest strength of815MPa compared to that of ratios A and B to-gether with the Rsu values differences between Q-1 toQ-2 and Q-3 it can be proved that by the optimi-zation of concrete mixing ratio the thermal per-formance was improved and the block compressivestrength was reduced Based on the above conclu-sions it is suggested that the two optimized mixingratios and block production process should be usedin TCB production

(3) e total thermal resistance Rsu of the block wall withthe mixing ratio A (Q-2) is 308 lower than that ofthe block wall with mixing ration B (Q-3) meaningthat the heat isolation properties of the mixing ratioA wall are better than that of the mixing ratio B wallAccording to the block compressive strength shownin Table 3 and the results in Section 2 the com-pressive strength of mixing ratio A is less than 5that of mixing ratio B Together with thermal pa-rameters in Table 6 it can be insufficiently provedthat the portion of mechanical sand and stonepowder is the key to control thermal insulation andmechanical performance more mechanical sand canimprove the strength and more stone powder canimprove the thermal insulation performance Butwhen considering there is a difference of 308 inRsubetween the A and B mixing ratios however thetrend is not obvious when considering the 7 dif-ference in the mechanical sand and stone powderpercentages in the A and B mixing ratios e in-fluence of mechanical sand and limestone powder

Table 3 Average compressive strength of blocks (MPa)

Mixing ratio A B A (6months in open air) B (6months in open air) Initial mixing ratioCompressive strength 688 657 741 684 815

6 Advances in Materials Science and Engineering

percentage should be further evaluated based onmore test cases

5 Finite Element Simulation

51 Finite Element Model e thermal analysis module in-tegrated in ANSYS finite element simulation software wasused to simulate the thermal performance of the TCB wall inheated steady state In the thermal simulation of wall

specimen in this study as the wall size is 12mtimes 12mtimes 02mof which the specimen front face sizes are much larger thanthe specimen thickness the heat energy flow simulation willbe simplified to be one-dimensional heat conduction simu-lation on the two-dimensional finite element model whichonly considers the heat energy flow in the thickness directionAnd as the thermal experimental testing was the steady-stateheat transfer performance testing the finite element simu-lation will also assume that the specimen was in steady-stateheat transfer situation Finally the finite element simulationadopted the following three assumptions

(1) Different material parts in TCB including the internalhollow concrete block part the extruded polystyrenelayer and the external block part will be assumed tobe inseparable connected and no material or thermalproperties changes with temperature

(2) e heat energy flow will only be in the thicknessdirection and the simulation will be simplified to beone-dimensional heat conduction simulation

(3) e simulation of the specimen is in the steady-stateheat transfer situation which means the environ-ment temperature of the two sides of the specimenremains constant

Based on the above assumptions and test method[20ndash22] the simulation element for the TCB wall wasselected as PLANE55 which is a two-dimensional thermalsolid element with 4 nodes and can be used as a planar oraxisymmetric element in two-dimensional heat steady-stage and instantaneous-stage analyses [23] e node inthe PLANE55 element only contains one temperaturedegree of freedom

52 Material Properties According to the experimental testresults and the theory of the parallel-series method inequations (1)mdash(5) the thermal conductivity of the concretefor mixing ratio A can be calculated as λk 1178W(mmiddotK)Other thermophysical parameters of related materials usedin the TCB are determined according to the testing standardof ldquoCode for ermal Design of Civil Buildingrdquo (GB 50176-2016) [24] and are shown in Table 7

53 Meshing and Boundary Conditions e finite elementgeometric model was automatically generated by the ANSYS

Specimen frame

ShelterHeating machine

Heat conduction screen

Heat circulating fan

Heat circulating pipeline

Cooling pipeline

Specimen

Cooling screen

Cooling fan

Cooler

Cooling machine

Figure 10 Schematic of the test machine for the joggled joint block wall thermal test

Figure 11 Testing machine in reality

Table 4 Specimen parameters

Specimen Block Size (mm)Q-1 Initial mixing ratio block 390times 300times115Q-2 A mixing ratio block 390times 300times115Q-3 B mixing ratio block 390times 300times115

Table 5 Initial parameters used for the thermal test

Air temperature of experimental heat box 300degCAir temperature of protective hot box 300degCAir temperature of cold box minus 100degCRelative humidity of experimental heat box 30Heat flux coefficient M3 of the external wall ofmeasuring heat box 152WK

Wall thickness 300mm

Advances in Materials Science and Engineering 7

simulation software and the mesh was discretized into atriangle or quadrilateral shape with 5mm mesh sizeCompared with the thermal experimental test results of thewall the interior temperature of the simulated wall was 30degCand the exterior temperature of the wall was minus 10degC efinite element simulation model assumed that the boundaryconditions are complete heat isolation the convective heattransfer is only applied on internal and external surfaceswhich are selected as boundary condition while no heattransfer exists on block connection joints e convectiveheat transfer coefficients of the interior and exterior were87W(m2 middotK) and 230 W(m2 middotK) respectively e sim-plified one-dimensional TCB wall model is shown in Fig-ure 12 e ANSYS geometric model is shown in Figure 13e mesh used for the joggled joint block wall model isshown in Figure 14

54 Simulation Results e finite element simulation cal-culated the temperature distribution and heat flux distribu-tion maps shown in Figures 15 and 16 According to the heatflux distribution map the average heat flux density Q1 can beobtained by ANSYS software And according to Fourierrsquos lawof heat conduction in equation (2) the thermal conductivityvalue can be obtained e relation between specimen totalthermal resistance and thermal conductivity can be obtainedby equation (3)e average thermal performance parametersof the wall specimen are shown in Table 8 By comparing thecalculation results with those obtained in the previous ex-perimental test it can be found that the numerical simulation

thermal resistance of the A mixing ratio block wall is2133(m2 middotK)W which is 61 higher than that obtainedfrom experimental testing of 1950(m2 middotK)W e relativeerror is caused by two reasons (1) the simulation modelassumes that the boundary conditions are complete heatisolation and inconsistent with reality (2) heat loss andmeasurement error are inevitable in the experimental testprocess Comparing the simulation results with the experi-mental results the relative error is low and acceptable

Figure 15 shows the temperature distribution of the TCBwall where it can be seen that the temperature decreasesgradually from the internal surface to the external surfaceHowever the area with the most rapid temperature decreasewas the heat isolation layer Because temperature variationrate is inversely proportional to the thermal conductivityvalue of the material and the thermal conductivity value ofthe extruded polystyrene layer is 0030W(mmiddotK) which is farless than the value of 1178W(mmiddotK) for concrete and0746W(mmiddotK) for air it can be proved that the extrudedpolystyrene layer contributes most of the heat isolationperformance It can be found in Figure 15 that the tem-perature boundary lines of 21degC and 25degC exhibited obviousfluctuations there was a high temperature distribution areain the middle position of block while low temperaturedistribution area is close to the block joint proving theexistence of thermal bridge caused by the block jointsHowever because the main heat isolation component is theextruded polystyrene layer the fluctuate depth of temper-ature was limited in the concrete part and no temperatureinfluence reached at the external surface

Tenon composite block Mortar joint

5 390 390 51010

1200

30degC interior temperature

ndash10degC interior temperature

300

390

Figure 12 Simplified heat transfer model of the block wall

Table 6 ermal parameters of test specimens

Specimen ermal resistanceR(m2 middotKW)

ermal conductivityλk (W(mmiddotK))

Heat transfer coefficientK (W(m2 middotK))

Total thermal resistanceRsu(m2 middotKW)

Q-1 1581 0632 0546 1830Q-2 1691 0591 0513 1950Q-3 1765 0567 0497 2010

Table 7 ermophysical parameters of materials in TCB

Material ermal conductivity (W(mmiddotK)) ickness (mm)Concrete 1178 195Extruded polystyrene layer 0030 65Vertical air interlayer 0746 135Masonry mortar 0930 25

8 Advances in Materials Science and Engineering

Figure 16 is the heat flux density distribution of thetenon connected block wall model in heat steady stage eheat flux density in most of the wall area is very low in-cluding the internal hollow concrete part the extrudedpolystyrene layer and the external concrete part whichindicated that the extruded polystyrene layer and the airinsulation layer effectively prevent heat transmissionHowever a very high heat flux density distributed at theblock joints which proved the same phenomenon of thethermal bridge in Figure 15

Concluding the temperature and heat flux density dis-tribution in Figures 15 and 16 the extruded polystyrenelayer contributed very reliable and continuous thermal

insulation performance which contributed to the staggeredarranged tenon avoiding the thickness reduction of extrudedpolystyrene layer is also proved the reasonability of thestaggered arranged tenon in this new TCB Apart from thereasonably arranged tenon the block joint still inevitablybecomes the heat bridge of tenon composite thermalinsulation wall and further study on avoiding heat bridge ofblock joint should be focused

6 Conclusion

e main conclusions obtained from the experimentaltesting and numerical simulation are as follows

Figure 13 Geometric model of the thermal analysis unit

Figure 14 Grid diagram of the thermal analysis unit

ndash10 ndash111111 777778 166667 25555630211111122222333333ndash555556

Figure 15 Cloud pattern of wall temperature distribution

122015 808705 160521 240171 319822410453 120696 200346 279997 359647

Figure 16 Distribution of heat flux density in the wall

Table 8 Total thermal resistance of the block wall in the experimental test and numerical simulation

Condition Total thermal resistance Ru (m2 middotK)W Relevant error

Experiment 2010 61Numerical simulation 2133

Advances in Materials Science and Engineering 9

(1) e experimental strength test of the blocks with threedifferent mixing ratios which were proposed by earlyexperimental test experiences and optimizationproved that the mixing ratios were reliable to supplyhigher strength than the design code required strength

(2) e experimental steady-state thermal test on TCBwall specimens indicated that the TCB wall specimenhas good thermal performance when compared tothe total thermal resistance with the common blockwall

(3) Experimental results from the thermal test and themechanical test proved that the A mixing ratio blockhad better thermal performance which contributesto the mechanical sand and stone powder percent-ages while very close strength to that of B mixingratio block erefore it is suggested that the opti-mized A mixing ratio can be used in the TCBproduction

(4) e numerical simulation provided acceptable andaccurate results with a low relative error e nu-merical simulation results proved the reasonabilityof the staggered arranged tenon to avoid thermalperformance reduction But the inevitable thermalbridge existed at the block joints and should befocused in further study

Nomenclature

Basic UnitsK Kelvin temperatureMPa Mega Pascalm Metermm MillimeterW Watts SeconddegC Celsius temperatureLatin and Greek lettersA Face area of specimen (m2)

K Heat transfer coefficient (W(m2 middotK))

M3 Heat flux coefficient of external wall of measuring heatbox (WK)

Q1 Heat flux rate (W)

R ermal resistance (m2 middotKW)

Rsu Total thermal resistance (m2 middotKW)

δ Specimen thickness (m)

λk ermal conductivity (W(mmiddotK))

AcronymsCO2 Carbon dioxideTCB Tenon composite block

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

is work was supported by the Science Project of JiangsuWater Conservancy Bureau (Grant no 2016038) the SocialDevelopment Project of Nanjing Science and TechnologyCommission Fund Programs (Grant no 201505018) and theNational Natural Science Foundation for Young Scientists ofChina (Grant no 51708260)

References

[1] A N Raut and C P Gomez ldquoAssessment of thermal andenergy performance of thermally efficient sustainable wallsystem for Malaysian low cost housingrdquo Applied -ermalEngineering vol 136 pp 309ndash318 2018

[2] G Vasconcelos P Lourenco P Mendonca et al ldquoProposal ofan innovative solution for partition walls mechanical ther-mal and acoustic validationrdquo Construction and BuildingMaterials vol 48 pp 961ndash979 2013

[3] R D Diao L Z Sun and F Yang ldquoermal performance ofbuilding wall materials in villages and towns in hot summerand cold winter zone in Chinardquo Applied-ermal Engineeringvol 128 pp 517ndash530 2018

[4] V Echarri-Iribarren C Rizo-Maestre and F Echarri-Iri-barren ldquoHealthy climate and energy savings using thermalceramic panels and solar thermal panels in mediterraneanhousing blocksrdquo Energies vol 11 no 10 2018

[5] M Fogiatto G Santos and J Catelan ldquoNumerical two-di-mensional steady-state evaluation of the thermal trans-mittance reduction in hollow blocksrdquo Energies vol 12 no 3p 449 2019

[6] E Wati P Meukam and J C Damfeu ldquoModeling thermalperformance of exterior walls retrofitted from insulation andmodified laterite based bricks materialsrdquo Heat and MassTransfer vol 53 no 12 pp 3487ndash3499 2017

[7] A Laaouatni N Martaj R Bennacer M Lachi M El Omariand M El Ganaoui ldquoermal building control using activeventilated block integrating phase change materialrdquo Energyand Buildings vol 187 pp 50ndash63 2019

[8] J Wu G L Bai P Wang and Y Liu ldquoMechanical propertiesof a new type of block made from shale and coal ganguerdquoConstruction and Building Materials vol 190 pp 796ndash8042018

[9] M X Xiong Y H Wang and J Y R Liew ldquoEvaluation onthermal behaviour of concrete-filled steel tubular columnsbased on modified finite difference methodrdquo Advances inStructural Engineering vol 19 no 5 pp 746ndash761 2016

[10] D Y Wu S T Liang M Y Shen Z X Guo X J Zhu andC F Sun ldquoExperimental estimation of seismic properties ofnew precast shear wall spatial structure modelrdquo EngineeringStructures vol 183 pp 319ndash339 2019

[11] D Y Wu S T Liang M Y Shen et al ldquoFinite-elementsimulation on NPGCS precast shear wall spatial structuremodelrdquo Advances in Civil Engineering vol 2019 Article ID2647891 17 pages 2019

[12] S Noor-E-Khuda and F Albermani ldquoMechanical propertiesof clay masonry units destructive and ultrasonic testingrdquoConstruction and Building Materials vol 219 pp 111ndash1202019

[13] I Gnip S Vejelis and S Vaitkus ldquoermal conductivity ofexpanded polystyrene (EPS) at 10 degrees C and its con-version to temperatures within interval from 0 to 50 degreesCrdquo Energy and Buildings vol 52 pp 107ndash111 2012

10 Advances in Materials Science and Engineering

[14] T eodosiou K Tsikaloudaki S Tsoka and P Chastasldquoermal bridging problems on advanced cladding systemsand smart building facadesrdquo Journal of Cleaner Productionvol 214 pp 62ndash69 2019

[15] P Brzyski M Grudzinska and D Majerek ldquoAnalysis of theoccurrence of thermal bridges in several variants of con-nections of the wall and the ground floor in constructionTechnology with the use of a hemp-lime compositerdquo Mate-rials vol 12 no 15 2019

[16] M Khoukhi ldquoe combined effect of heat and moisturetransfer dependent thermal conductivity of polystyreneinsulation material impact on building energy performancerdquoEnergy and Buildings vol 169 pp 228ndash235 2018

[17] GBT13475-2008 Building Element-Determination of Steady-State -ermal Transmission PropertiesndashCalibrated andGuarded Hot Box China Architecture amp Building PressBeijing China 2008

[18] GBT4111-2013 Test Methods for the Concrete Block andBrick China Architecture amp Building Press Beijing China2013

[19] GB50003-2011 Code for Design of Masonry Structures ChinaArchitecture amp Building Press Beijing China 2011

[20] H Yang X Xu W Xu and I Neumann ldquoTerrestrial laserscanning-based deformation analysis for arch and beamstructuresrdquo IEEE Sensors Journal vol 17 no 14 pp 4605ndash4611 2017

[21] H Yang X Xu and I Neumann ldquoDeformation behavioranalysis of composite structures under monotonic loads basedon terrestrial laser scanning Technologyrdquo Composite Struc-tures vol 183 pp 594ndash599 2017

[22] H Yang X Xu and I Neumann ldquoLaser scanning-basedupdating of a finite-element model for structural healthmonitoringrdquo IEEE Sensors Journal vol 16 no 7 pp 2100ndash2104 2016

[23] V Koci J Koci J Madera et al ldquoermal and hygric as-sessment of an inside-insulated brick wall 2D critical ex-periment and computational analysisrdquo Journal of BuildingPhysics vol 41 no 6 pp 497ndash520 2018

[24] GB 50176-2016 Code for -ermal Design of Civil BuildingChina Architecture amp Building Press Beijing China 2016

Advances in Materials Science and Engineering 11

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

which consists of cement stone powder fly ash and water-reducing agent according to the mixing ratio the coarseaggregate and water are not included in this stepe secondstep consists of stirring for 1minute with 12 of the requiredwater and at least 2minutes of stirring after the addition ofall the remaining coarse aggregate and water

After the prepared hard concrete was added into theblock cast mold the block was formed with the pressuregenerated by the microcomputer-controlled electrohy-draulic servo-loading system as shown in Figure 6 Fol-lowing the block formation the block can be easily releasedby lifting the upper hydraulic jack as shown in Figure 7

e block products are shown in Figure 8 e curingprocess for all blocks was in the natural environment wherethe blocks were covered with straw and watered for the first14 days after the blocks were released A TCB after 28 days ofstandard curing is shown in Figure 9

3 Strength Test

Ten blocks from each mixing ratio (A and B) were randomlyselected and divided into two groups to test the strengthEach group contained five blocks from every mixing ratioOne group (5 from A and 5 from B) was tested after blockproduction e blocks in the other group (5 from A and 5from B) were tested after being placed for 6months in open-air conditions e strength tests used a WAW-1000 elec-trohydraulic servo-testing machine e loading speed wascontrolled to be 02ndash03MPas and the loading continueduntil a vertical crack appeared on the block according toldquoTest Methods for the Concrete Block and Brickrdquo [18]Limited by experimental conditions of the WAW-1000electrohydraulic servo-testing machine the effect of porosityand eccentricity were not considered in the strength testeaverage compressive strengths are shown in Table 3

e average compressive strength for each case is shownin Table 3 Effect of porosity and eccentricity on the me-chanical properties can be found e strength requirementof 5MPa [19] was exceeded for each case meaning that thethree concrete mixing ratios can be applied to blocks used asinfill walls and load-bearing walls in multilayer masonrystructures As in the block manufacturing process the po-rosity was mainly controlled in the materials stirring and

Table 2 Optimized A and B mixing ratios ()

Cement Gravel (mechanical sand) Stone powder Ceramsite Medium sand Fly ash Water-reducing agent WaterInitial ratio 20 20 33 12 7 2 6Mixing ratio A 18 25 18 8 10 10 2 9Mixing ratio B 18 18 25 8 10 10 2 9

Cleaning and fixing block equipment

Preparing

Materials mixing stepRequirements 1-minute stirring for raw materials with half required water and at

least 2 minutes of stirring with all remaining coarse aggregate and water

Achievement finished concrete material

Concrete production processEquipment vertical material mixer

Premixing step Requirements all raw materials except

coarse aggregate and water mixing for 20 seconds

Achievement uniform mixture of materials

Block production processEquipment cast mold electrohydraulic

servo-loading system

Block casting and forming Requirements the block was formed in the block cast mold with the pressure generated

by the microcomputer-controlled electrohydraulic servo-loading system

Achievement complete block

Block releasing and curing Requirement block is released by hydraulic jack and cured for 28 days standard curing

Achievement to release the block out of mold and generate block strength

Figure 4 Manufacturing process of the new TCB

Figure 5 e extruded polystyrene heat insulation layer locationin the mold

4 Advances in Materials Science and Engineering

block casting step in the manufacturing process the testingstrength of TCB matched the strength requirements ofdesign codes proving that the porosity was well controlled inthe manufacturing process

e compressive strength of mixing ratio A is less than5 that of mixing ratio B e main difference between

mixing ratio A and B is the portion of mechanical sand andstone powder e mechanical sand percentage in mixingratio A is higher but as a coarse aggregate mechanical sandimproved the strength and reduced the thermal insulationperformanceerefore the thermal insulation performanceof mixing ratios A and B is discussed below in Section 3together with mechanical performance

Blocks with the A and B mixing ratios with open-airplacing for 6months after manufacture have 77 and 41higher in average compressive strengths respectively thanthe A and Bmixing ratio blocks after productionis meansthe chemical reaction of material components continued toincrease the strength with time Finally the TCB with theinitial concrete mixing ratio had the highest strength of 815MPa compared to that of ratios A and B meaning that theoptimization of the thermal performance caused a reductionin the block compressive strength

4 Thermal Testing

41 -ermal Testing Apparatus and Specimens e WTRZ-1212 steady-state heat transfer performance testing machinewas used for this test which was developed and producedstrictly according to the requirements in the national teststandard of ldquoBuilding Element-Determination of Steady-State

(a) (b)

Figure 6 Blocks being formed (a) Concrete being prepared (b) Pressure being applied by a hydraulic jack

Figure 7 Upper hydraulic jack being lifted to release the block

Figure 8 Blocks being cured

Figure 9 Block after the curing process

Advances in Materials Science and Engineering 5

ermal Transmission PropertiesmdashCalibrated and GuardedHot Boxrdquo (GBT13475-2008) in China [17] e maximumsample size for standard WTRZ-1212 is 164mtimes 164m andthe measuring size of the TCB wall specimen is 12mtimes 12me testingmachine is shown in Figure 10e test is based onthe guarding hot-box method which relies on a heat pro-tective box to balance external and internal environments andquantitatively analyze thermal performance with minimizedheat consumption and high accuracy e box is also opti-mized to reduce error by synthetically measuring the heat lossof test instruments e testing machine and specimen inreality are shown in Figure 11

ree TCB wall specimens were tested to compare thethermal performance using different concrete mix pro-portions initial mixing ratio and the A and B mixing ratiose block and wall parameters are shown in Table 4 Table 5shows the initial parameters used for the thermal test

42 -ermal Test Results e three TCB wall specimenswere tested strictly according to the national test standard ofldquoBuilding Element-Determination of Steady-State ermalTransmission PropertiesmdashCalibrated and Guarded HotBoxrdquo (GBT13475-2008) [17] In the test the heating powerQp of the heating machine shown in Figure 12 will becollected Apart from that the temperature difference θ3between the inner wall and the outer wall of shelter inheating part (Figure 12) the hot surface temperature Tsi andthe cool surface temperature Tse of the specimen the airtemperature of protective hot box Tni and the air temper-atures of cool box Tne will be collected among which the Tniand Tne were set to be 30degC and minus 10degC in the test but werestill collected to consider testing errors and to improvetesting accuracy e thermal parameters of the three blockwall specimens can be calculated from the collected data andaccording to equations (1)mdash(5) shown in Table 6 includingthe thermal resistance the thermal conductivity the heattransfer coefficient and the total thermal resistance

Q1 QP minus M3θ3 (1)

R A Tsi minus Tse( 1113857

Q1 (2)

λk δR

(3)

K Q1

A Tni minus Tne( 11138571113858 1113859 (4)

Rsu 1K

(5)

From the thermal parameters in Table 6 the followingconclusions can be drawn

(1) e TCB specimens have good total thermal per-formance when compared the total thermal re-sistance Rsu to the Rsu value of 30m2 middot KW ofcommon block wall in which the block has threerows of heat isolation holes and size of390mmtimes 190mmtimes 190mm e Rsu values of theTCB wall are 610 650 and 670 times of the totalthermal resistance of common block wall for the Q-1the Q-2 and the Q-3 respectively

(2) According to the total thermal resistance Rsu valuesof the three wall specimens of Q-1 Q-2 and Q-3 theheat insulation properties of the TCB walls withmixing ratios A and B are 656 and 984 higherthan that of specimen with the initial mixing ratiorespectively which indicates that the mixing ratioand production processing optimization have im-proved thermal performance As this study con-cluded in Section 2 that the TCB with the initialconcrete mixing ratio had the highest strength of815MPa compared to that of ratios A and B to-gether with the Rsu values differences between Q-1 toQ-2 and Q-3 it can be proved that by the optimi-zation of concrete mixing ratio the thermal per-formance was improved and the block compressivestrength was reduced Based on the above conclu-sions it is suggested that the two optimized mixingratios and block production process should be usedin TCB production

(3) e total thermal resistance Rsu of the block wall withthe mixing ratio A (Q-2) is 308 lower than that ofthe block wall with mixing ration B (Q-3) meaningthat the heat isolation properties of the mixing ratioA wall are better than that of the mixing ratio B wallAccording to the block compressive strength shownin Table 3 and the results in Section 2 the com-pressive strength of mixing ratio A is less than 5that of mixing ratio B Together with thermal pa-rameters in Table 6 it can be insufficiently provedthat the portion of mechanical sand and stonepowder is the key to control thermal insulation andmechanical performance more mechanical sand canimprove the strength and more stone powder canimprove the thermal insulation performance Butwhen considering there is a difference of 308 inRsubetween the A and B mixing ratios however thetrend is not obvious when considering the 7 dif-ference in the mechanical sand and stone powderpercentages in the A and B mixing ratios e in-fluence of mechanical sand and limestone powder

Table 3 Average compressive strength of blocks (MPa)

Mixing ratio A B A (6months in open air) B (6months in open air) Initial mixing ratioCompressive strength 688 657 741 684 815

6 Advances in Materials Science and Engineering

percentage should be further evaluated based onmore test cases

5 Finite Element Simulation

51 Finite Element Model e thermal analysis module in-tegrated in ANSYS finite element simulation software wasused to simulate the thermal performance of the TCB wall inheated steady state In the thermal simulation of wall

specimen in this study as the wall size is 12mtimes 12mtimes 02mof which the specimen front face sizes are much larger thanthe specimen thickness the heat energy flow simulation willbe simplified to be one-dimensional heat conduction simu-lation on the two-dimensional finite element model whichonly considers the heat energy flow in the thickness directionAnd as the thermal experimental testing was the steady-stateheat transfer performance testing the finite element simu-lation will also assume that the specimen was in steady-stateheat transfer situation Finally the finite element simulationadopted the following three assumptions

(1) Different material parts in TCB including the internalhollow concrete block part the extruded polystyrenelayer and the external block part will be assumed tobe inseparable connected and no material or thermalproperties changes with temperature

(2) e heat energy flow will only be in the thicknessdirection and the simulation will be simplified to beone-dimensional heat conduction simulation

(3) e simulation of the specimen is in the steady-stateheat transfer situation which means the environ-ment temperature of the two sides of the specimenremains constant

Based on the above assumptions and test method[20ndash22] the simulation element for the TCB wall wasselected as PLANE55 which is a two-dimensional thermalsolid element with 4 nodes and can be used as a planar oraxisymmetric element in two-dimensional heat steady-stage and instantaneous-stage analyses [23] e node inthe PLANE55 element only contains one temperaturedegree of freedom

52 Material Properties According to the experimental testresults and the theory of the parallel-series method inequations (1)mdash(5) the thermal conductivity of the concretefor mixing ratio A can be calculated as λk 1178W(mmiddotK)Other thermophysical parameters of related materials usedin the TCB are determined according to the testing standardof ldquoCode for ermal Design of Civil Buildingrdquo (GB 50176-2016) [24] and are shown in Table 7

53 Meshing and Boundary Conditions e finite elementgeometric model was automatically generated by the ANSYS

Specimen frame

ShelterHeating machine

Heat conduction screen

Heat circulating fan

Heat circulating pipeline

Cooling pipeline

Specimen

Cooling screen

Cooling fan

Cooler

Cooling machine

Figure 10 Schematic of the test machine for the joggled joint block wall thermal test

Figure 11 Testing machine in reality

Table 4 Specimen parameters

Specimen Block Size (mm)Q-1 Initial mixing ratio block 390times 300times115Q-2 A mixing ratio block 390times 300times115Q-3 B mixing ratio block 390times 300times115

Table 5 Initial parameters used for the thermal test

Air temperature of experimental heat box 300degCAir temperature of protective hot box 300degCAir temperature of cold box minus 100degCRelative humidity of experimental heat box 30Heat flux coefficient M3 of the external wall ofmeasuring heat box 152WK

Wall thickness 300mm

Advances in Materials Science and Engineering 7

simulation software and the mesh was discretized into atriangle or quadrilateral shape with 5mm mesh sizeCompared with the thermal experimental test results of thewall the interior temperature of the simulated wall was 30degCand the exterior temperature of the wall was minus 10degC efinite element simulation model assumed that the boundaryconditions are complete heat isolation the convective heattransfer is only applied on internal and external surfaceswhich are selected as boundary condition while no heattransfer exists on block connection joints e convectiveheat transfer coefficients of the interior and exterior were87W(m2 middotK) and 230 W(m2 middotK) respectively e sim-plified one-dimensional TCB wall model is shown in Fig-ure 12 e ANSYS geometric model is shown in Figure 13e mesh used for the joggled joint block wall model isshown in Figure 14

54 Simulation Results e finite element simulation cal-culated the temperature distribution and heat flux distribu-tion maps shown in Figures 15 and 16 According to the heatflux distribution map the average heat flux density Q1 can beobtained by ANSYS software And according to Fourierrsquos lawof heat conduction in equation (2) the thermal conductivityvalue can be obtained e relation between specimen totalthermal resistance and thermal conductivity can be obtainedby equation (3)e average thermal performance parametersof the wall specimen are shown in Table 8 By comparing thecalculation results with those obtained in the previous ex-perimental test it can be found that the numerical simulation

thermal resistance of the A mixing ratio block wall is2133(m2 middotK)W which is 61 higher than that obtainedfrom experimental testing of 1950(m2 middotK)W e relativeerror is caused by two reasons (1) the simulation modelassumes that the boundary conditions are complete heatisolation and inconsistent with reality (2) heat loss andmeasurement error are inevitable in the experimental testprocess Comparing the simulation results with the experi-mental results the relative error is low and acceptable

Figure 15 shows the temperature distribution of the TCBwall where it can be seen that the temperature decreasesgradually from the internal surface to the external surfaceHowever the area with the most rapid temperature decreasewas the heat isolation layer Because temperature variationrate is inversely proportional to the thermal conductivityvalue of the material and the thermal conductivity value ofthe extruded polystyrene layer is 0030W(mmiddotK) which is farless than the value of 1178W(mmiddotK) for concrete and0746W(mmiddotK) for air it can be proved that the extrudedpolystyrene layer contributes most of the heat isolationperformance It can be found in Figure 15 that the tem-perature boundary lines of 21degC and 25degC exhibited obviousfluctuations there was a high temperature distribution areain the middle position of block while low temperaturedistribution area is close to the block joint proving theexistence of thermal bridge caused by the block jointsHowever because the main heat isolation component is theextruded polystyrene layer the fluctuate depth of temper-ature was limited in the concrete part and no temperatureinfluence reached at the external surface

Tenon composite block Mortar joint

5 390 390 51010

1200

30degC interior temperature

ndash10degC interior temperature

300

390

Figure 12 Simplified heat transfer model of the block wall

Table 6 ermal parameters of test specimens

Specimen ermal resistanceR(m2 middotKW)

ermal conductivityλk (W(mmiddotK))

Heat transfer coefficientK (W(m2 middotK))

Total thermal resistanceRsu(m2 middotKW)

Q-1 1581 0632 0546 1830Q-2 1691 0591 0513 1950Q-3 1765 0567 0497 2010

Table 7 ermophysical parameters of materials in TCB

Material ermal conductivity (W(mmiddotK)) ickness (mm)Concrete 1178 195Extruded polystyrene layer 0030 65Vertical air interlayer 0746 135Masonry mortar 0930 25

8 Advances in Materials Science and Engineering

Figure 16 is the heat flux density distribution of thetenon connected block wall model in heat steady stage eheat flux density in most of the wall area is very low in-cluding the internal hollow concrete part the extrudedpolystyrene layer and the external concrete part whichindicated that the extruded polystyrene layer and the airinsulation layer effectively prevent heat transmissionHowever a very high heat flux density distributed at theblock joints which proved the same phenomenon of thethermal bridge in Figure 15

Concluding the temperature and heat flux density dis-tribution in Figures 15 and 16 the extruded polystyrenelayer contributed very reliable and continuous thermal

insulation performance which contributed to the staggeredarranged tenon avoiding the thickness reduction of extrudedpolystyrene layer is also proved the reasonability of thestaggered arranged tenon in this new TCB Apart from thereasonably arranged tenon the block joint still inevitablybecomes the heat bridge of tenon composite thermalinsulation wall and further study on avoiding heat bridge ofblock joint should be focused

6 Conclusion

e main conclusions obtained from the experimentaltesting and numerical simulation are as follows

Figure 13 Geometric model of the thermal analysis unit

Figure 14 Grid diagram of the thermal analysis unit

ndash10 ndash111111 777778 166667 25555630211111122222333333ndash555556

Figure 15 Cloud pattern of wall temperature distribution

122015 808705 160521 240171 319822410453 120696 200346 279997 359647

Figure 16 Distribution of heat flux density in the wall

Table 8 Total thermal resistance of the block wall in the experimental test and numerical simulation

Condition Total thermal resistance Ru (m2 middotK)W Relevant error

Experiment 2010 61Numerical simulation 2133

Advances in Materials Science and Engineering 9

(1) e experimental strength test of the blocks with threedifferent mixing ratios which were proposed by earlyexperimental test experiences and optimizationproved that the mixing ratios were reliable to supplyhigher strength than the design code required strength

(2) e experimental steady-state thermal test on TCBwall specimens indicated that the TCB wall specimenhas good thermal performance when compared tothe total thermal resistance with the common blockwall

(3) Experimental results from the thermal test and themechanical test proved that the A mixing ratio blockhad better thermal performance which contributesto the mechanical sand and stone powder percent-ages while very close strength to that of B mixingratio block erefore it is suggested that the opti-mized A mixing ratio can be used in the TCBproduction

(4) e numerical simulation provided acceptable andaccurate results with a low relative error e nu-merical simulation results proved the reasonabilityof the staggered arranged tenon to avoid thermalperformance reduction But the inevitable thermalbridge existed at the block joints and should befocused in further study

Nomenclature

Basic UnitsK Kelvin temperatureMPa Mega Pascalm Metermm MillimeterW Watts SeconddegC Celsius temperatureLatin and Greek lettersA Face area of specimen (m2)

K Heat transfer coefficient (W(m2 middotK))

M3 Heat flux coefficient of external wall of measuring heatbox (WK)

Q1 Heat flux rate (W)

R ermal resistance (m2 middotKW)

Rsu Total thermal resistance (m2 middotKW)

δ Specimen thickness (m)

λk ermal conductivity (W(mmiddotK))

AcronymsCO2 Carbon dioxideTCB Tenon composite block

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

is work was supported by the Science Project of JiangsuWater Conservancy Bureau (Grant no 2016038) the SocialDevelopment Project of Nanjing Science and TechnologyCommission Fund Programs (Grant no 201505018) and theNational Natural Science Foundation for Young Scientists ofChina (Grant no 51708260)

References

[1] A N Raut and C P Gomez ldquoAssessment of thermal andenergy performance of thermally efficient sustainable wallsystem for Malaysian low cost housingrdquo Applied -ermalEngineering vol 136 pp 309ndash318 2018

[2] G Vasconcelos P Lourenco P Mendonca et al ldquoProposal ofan innovative solution for partition walls mechanical ther-mal and acoustic validationrdquo Construction and BuildingMaterials vol 48 pp 961ndash979 2013

[3] R D Diao L Z Sun and F Yang ldquoermal performance ofbuilding wall materials in villages and towns in hot summerand cold winter zone in Chinardquo Applied-ermal Engineeringvol 128 pp 517ndash530 2018

[4] V Echarri-Iribarren C Rizo-Maestre and F Echarri-Iri-barren ldquoHealthy climate and energy savings using thermalceramic panels and solar thermal panels in mediterraneanhousing blocksrdquo Energies vol 11 no 10 2018

[5] M Fogiatto G Santos and J Catelan ldquoNumerical two-di-mensional steady-state evaluation of the thermal trans-mittance reduction in hollow blocksrdquo Energies vol 12 no 3p 449 2019

[6] E Wati P Meukam and J C Damfeu ldquoModeling thermalperformance of exterior walls retrofitted from insulation andmodified laterite based bricks materialsrdquo Heat and MassTransfer vol 53 no 12 pp 3487ndash3499 2017

[7] A Laaouatni N Martaj R Bennacer M Lachi M El Omariand M El Ganaoui ldquoermal building control using activeventilated block integrating phase change materialrdquo Energyand Buildings vol 187 pp 50ndash63 2019

[8] J Wu G L Bai P Wang and Y Liu ldquoMechanical propertiesof a new type of block made from shale and coal ganguerdquoConstruction and Building Materials vol 190 pp 796ndash8042018

[9] M X Xiong Y H Wang and J Y R Liew ldquoEvaluation onthermal behaviour of concrete-filled steel tubular columnsbased on modified finite difference methodrdquo Advances inStructural Engineering vol 19 no 5 pp 746ndash761 2016

[10] D Y Wu S T Liang M Y Shen Z X Guo X J Zhu andC F Sun ldquoExperimental estimation of seismic properties ofnew precast shear wall spatial structure modelrdquo EngineeringStructures vol 183 pp 319ndash339 2019

[11] D Y Wu S T Liang M Y Shen et al ldquoFinite-elementsimulation on NPGCS precast shear wall spatial structuremodelrdquo Advances in Civil Engineering vol 2019 Article ID2647891 17 pages 2019

[12] S Noor-E-Khuda and F Albermani ldquoMechanical propertiesof clay masonry units destructive and ultrasonic testingrdquoConstruction and Building Materials vol 219 pp 111ndash1202019

[13] I Gnip S Vejelis and S Vaitkus ldquoermal conductivity ofexpanded polystyrene (EPS) at 10 degrees C and its con-version to temperatures within interval from 0 to 50 degreesCrdquo Energy and Buildings vol 52 pp 107ndash111 2012

10 Advances in Materials Science and Engineering

[14] T eodosiou K Tsikaloudaki S Tsoka and P Chastasldquoermal bridging problems on advanced cladding systemsand smart building facadesrdquo Journal of Cleaner Productionvol 214 pp 62ndash69 2019

[15] P Brzyski M Grudzinska and D Majerek ldquoAnalysis of theoccurrence of thermal bridges in several variants of con-nections of the wall and the ground floor in constructionTechnology with the use of a hemp-lime compositerdquo Mate-rials vol 12 no 15 2019

[16] M Khoukhi ldquoe combined effect of heat and moisturetransfer dependent thermal conductivity of polystyreneinsulation material impact on building energy performancerdquoEnergy and Buildings vol 169 pp 228ndash235 2018

[17] GBT13475-2008 Building Element-Determination of Steady-State -ermal Transmission PropertiesndashCalibrated andGuarded Hot Box China Architecture amp Building PressBeijing China 2008

[18] GBT4111-2013 Test Methods for the Concrete Block andBrick China Architecture amp Building Press Beijing China2013

[19] GB50003-2011 Code for Design of Masonry Structures ChinaArchitecture amp Building Press Beijing China 2011

[20] H Yang X Xu W Xu and I Neumann ldquoTerrestrial laserscanning-based deformation analysis for arch and beamstructuresrdquo IEEE Sensors Journal vol 17 no 14 pp 4605ndash4611 2017

[21] H Yang X Xu and I Neumann ldquoDeformation behavioranalysis of composite structures under monotonic loads basedon terrestrial laser scanning Technologyrdquo Composite Struc-tures vol 183 pp 594ndash599 2017

[22] H Yang X Xu and I Neumann ldquoLaser scanning-basedupdating of a finite-element model for structural healthmonitoringrdquo IEEE Sensors Journal vol 16 no 7 pp 2100ndash2104 2016

[23] V Koci J Koci J Madera et al ldquoermal and hygric as-sessment of an inside-insulated brick wall 2D critical ex-periment and computational analysisrdquo Journal of BuildingPhysics vol 41 no 6 pp 497ndash520 2018

[24] GB 50176-2016 Code for -ermal Design of Civil BuildingChina Architecture amp Building Press Beijing China 2016

Advances in Materials Science and Engineering 11

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Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom

block casting step in the manufacturing process the testingstrength of TCB matched the strength requirements ofdesign codes proving that the porosity was well controlled inthe manufacturing process

e compressive strength of mixing ratio A is less than5 that of mixing ratio B e main difference between

mixing ratio A and B is the portion of mechanical sand andstone powder e mechanical sand percentage in mixingratio A is higher but as a coarse aggregate mechanical sandimproved the strength and reduced the thermal insulationperformanceerefore the thermal insulation performanceof mixing ratios A and B is discussed below in Section 3together with mechanical performance

Blocks with the A and B mixing ratios with open-airplacing for 6months after manufacture have 77 and 41higher in average compressive strengths respectively thanthe A and Bmixing ratio blocks after productionis meansthe chemical reaction of material components continued toincrease the strength with time Finally the TCB with theinitial concrete mixing ratio had the highest strength of 815MPa compared to that of ratios A and B meaning that theoptimization of the thermal performance caused a reductionin the block compressive strength

4 Thermal Testing

41 -ermal Testing Apparatus and Specimens e WTRZ-1212 steady-state heat transfer performance testing machinewas used for this test which was developed and producedstrictly according to the requirements in the national teststandard of ldquoBuilding Element-Determination of Steady-State

(a) (b)

Figure 6 Blocks being formed (a) Concrete being prepared (b) Pressure being applied by a hydraulic jack

Figure 7 Upper hydraulic jack being lifted to release the block

Figure 8 Blocks being cured

Figure 9 Block after the curing process

Advances in Materials Science and Engineering 5

ermal Transmission PropertiesmdashCalibrated and GuardedHot Boxrdquo (GBT13475-2008) in China [17] e maximumsample size for standard WTRZ-1212 is 164mtimes 164m andthe measuring size of the TCB wall specimen is 12mtimes 12me testingmachine is shown in Figure 10e test is based onthe guarding hot-box method which relies on a heat pro-tective box to balance external and internal environments andquantitatively analyze thermal performance with minimizedheat consumption and high accuracy e box is also opti-mized to reduce error by synthetically measuring the heat lossof test instruments e testing machine and specimen inreality are shown in Figure 11

ree TCB wall specimens were tested to compare thethermal performance using different concrete mix pro-portions initial mixing ratio and the A and B mixing ratiose block and wall parameters are shown in Table 4 Table 5shows the initial parameters used for the thermal test

42 -ermal Test Results e three TCB wall specimenswere tested strictly according to the national test standard ofldquoBuilding Element-Determination of Steady-State ermalTransmission PropertiesmdashCalibrated and Guarded HotBoxrdquo (GBT13475-2008) [17] In the test the heating powerQp of the heating machine shown in Figure 12 will becollected Apart from that the temperature difference θ3between the inner wall and the outer wall of shelter inheating part (Figure 12) the hot surface temperature Tsi andthe cool surface temperature Tse of the specimen the airtemperature of protective hot box Tni and the air temper-atures of cool box Tne will be collected among which the Tniand Tne were set to be 30degC and minus 10degC in the test but werestill collected to consider testing errors and to improvetesting accuracy e thermal parameters of the three blockwall specimens can be calculated from the collected data andaccording to equations (1)mdash(5) shown in Table 6 includingthe thermal resistance the thermal conductivity the heattransfer coefficient and the total thermal resistance

Q1 QP minus M3θ3 (1)

R A Tsi minus Tse( 1113857

Q1 (2)

λk δR

(3)

K Q1

A Tni minus Tne( 11138571113858 1113859 (4)

Rsu 1K

(5)

From the thermal parameters in Table 6 the followingconclusions can be drawn

(1) e TCB specimens have good total thermal per-formance when compared the total thermal re-sistance Rsu to the Rsu value of 30m2 middot KW ofcommon block wall in which the block has threerows of heat isolation holes and size of390mmtimes 190mmtimes 190mm e Rsu values of theTCB wall are 610 650 and 670 times of the totalthermal resistance of common block wall for the Q-1the Q-2 and the Q-3 respectively

(2) According to the total thermal resistance Rsu valuesof the three wall specimens of Q-1 Q-2 and Q-3 theheat insulation properties of the TCB walls withmixing ratios A and B are 656 and 984 higherthan that of specimen with the initial mixing ratiorespectively which indicates that the mixing ratioand production processing optimization have im-proved thermal performance As this study con-cluded in Section 2 that the TCB with the initialconcrete mixing ratio had the highest strength of815MPa compared to that of ratios A and B to-gether with the Rsu values differences between Q-1 toQ-2 and Q-3 it can be proved that by the optimi-zation of concrete mixing ratio the thermal per-formance was improved and the block compressivestrength was reduced Based on the above conclu-sions it is suggested that the two optimized mixingratios and block production process should be usedin TCB production

(3) e total thermal resistance Rsu of the block wall withthe mixing ratio A (Q-2) is 308 lower than that ofthe block wall with mixing ration B (Q-3) meaningthat the heat isolation properties of the mixing ratioA wall are better than that of the mixing ratio B wallAccording to the block compressive strength shownin Table 3 and the results in Section 2 the com-pressive strength of mixing ratio A is less than 5that of mixing ratio B Together with thermal pa-rameters in Table 6 it can be insufficiently provedthat the portion of mechanical sand and stonepowder is the key to control thermal insulation andmechanical performance more mechanical sand canimprove the strength and more stone powder canimprove the thermal insulation performance Butwhen considering there is a difference of 308 inRsubetween the A and B mixing ratios however thetrend is not obvious when considering the 7 dif-ference in the mechanical sand and stone powderpercentages in the A and B mixing ratios e in-fluence of mechanical sand and limestone powder

Table 3 Average compressive strength of blocks (MPa)

Mixing ratio A B A (6months in open air) B (6months in open air) Initial mixing ratioCompressive strength 688 657 741 684 815

6 Advances in Materials Science and Engineering

percentage should be further evaluated based onmore test cases

5 Finite Element Simulation

51 Finite Element Model e thermal analysis module in-tegrated in ANSYS finite element simulation software wasused to simulate the thermal performance of the TCB wall inheated steady state In the thermal simulation of wall

specimen in this study as the wall size is 12mtimes 12mtimes 02mof which the specimen front face sizes are much larger thanthe specimen thickness the heat energy flow simulation willbe simplified to be one-dimensional heat conduction simu-lation on the two-dimensional finite element model whichonly considers the heat energy flow in the thickness directionAnd as the thermal experimental testing was the steady-stateheat transfer performance testing the finite element simu-lation will also assume that the specimen was in steady-stateheat transfer situation Finally the finite element simulationadopted the following three assumptions

(1) Different material parts in TCB including the internalhollow concrete block part the extruded polystyrenelayer and the external block part will be assumed tobe inseparable connected and no material or thermalproperties changes with temperature

(2) e heat energy flow will only be in the thicknessdirection and the simulation will be simplified to beone-dimensional heat conduction simulation

(3) e simulation of the specimen is in the steady-stateheat transfer situation which means the environ-ment temperature of the two sides of the specimenremains constant

Based on the above assumptions and test method[20ndash22] the simulation element for the TCB wall wasselected as PLANE55 which is a two-dimensional thermalsolid element with 4 nodes and can be used as a planar oraxisymmetric element in two-dimensional heat steady-stage and instantaneous-stage analyses [23] e node inthe PLANE55 element only contains one temperaturedegree of freedom

52 Material Properties According to the experimental testresults and the theory of the parallel-series method inequations (1)mdash(5) the thermal conductivity of the concretefor mixing ratio A can be calculated as λk 1178W(mmiddotK)Other thermophysical parameters of related materials usedin the TCB are determined according to the testing standardof ldquoCode for ermal Design of Civil Buildingrdquo (GB 50176-2016) [24] and are shown in Table 7

53 Meshing and Boundary Conditions e finite elementgeometric model was automatically generated by the ANSYS

Specimen frame

ShelterHeating machine

Heat conduction screen

Heat circulating fan

Heat circulating pipeline

Cooling pipeline

Specimen

Cooling screen

Cooling fan

Cooler

Cooling machine

Figure 10 Schematic of the test machine for the joggled joint block wall thermal test

Figure 11 Testing machine in reality

Table 4 Specimen parameters

Specimen Block Size (mm)Q-1 Initial mixing ratio block 390times 300times115Q-2 A mixing ratio block 390times 300times115Q-3 B mixing ratio block 390times 300times115

Table 5 Initial parameters used for the thermal test

Air temperature of experimental heat box 300degCAir temperature of protective hot box 300degCAir temperature of cold box minus 100degCRelative humidity of experimental heat box 30Heat flux coefficient M3 of the external wall ofmeasuring heat box 152WK

Wall thickness 300mm

Advances in Materials Science and Engineering 7

simulation software and the mesh was discretized into atriangle or quadrilateral shape with 5mm mesh sizeCompared with the thermal experimental test results of thewall the interior temperature of the simulated wall was 30degCand the exterior temperature of the wall was minus 10degC efinite element simulation model assumed that the boundaryconditions are complete heat isolation the convective heattransfer is only applied on internal and external surfaceswhich are selected as boundary condition while no heattransfer exists on block connection joints e convectiveheat transfer coefficients of the interior and exterior were87W(m2 middotK) and 230 W(m2 middotK) respectively e sim-plified one-dimensional TCB wall model is shown in Fig-ure 12 e ANSYS geometric model is shown in Figure 13e mesh used for the joggled joint block wall model isshown in Figure 14

54 Simulation Results e finite element simulation cal-culated the temperature distribution and heat flux distribu-tion maps shown in Figures 15 and 16 According to the heatflux distribution map the average heat flux density Q1 can beobtained by ANSYS software And according to Fourierrsquos lawof heat conduction in equation (2) the thermal conductivityvalue can be obtained e relation between specimen totalthermal resistance and thermal conductivity can be obtainedby equation (3)e average thermal performance parametersof the wall specimen are shown in Table 8 By comparing thecalculation results with those obtained in the previous ex-perimental test it can be found that the numerical simulation

thermal resistance of the A mixing ratio block wall is2133(m2 middotK)W which is 61 higher than that obtainedfrom experimental testing of 1950(m2 middotK)W e relativeerror is caused by two reasons (1) the simulation modelassumes that the boundary conditions are complete heatisolation and inconsistent with reality (2) heat loss andmeasurement error are inevitable in the experimental testprocess Comparing the simulation results with the experi-mental results the relative error is low and acceptable

Figure 15 shows the temperature distribution of the TCBwall where it can be seen that the temperature decreasesgradually from the internal surface to the external surfaceHowever the area with the most rapid temperature decreasewas the heat isolation layer Because temperature variationrate is inversely proportional to the thermal conductivityvalue of the material and the thermal conductivity value ofthe extruded polystyrene layer is 0030W(mmiddotK) which is farless than the value of 1178W(mmiddotK) for concrete and0746W(mmiddotK) for air it can be proved that the extrudedpolystyrene layer contributes most of the heat isolationperformance It can be found in Figure 15 that the tem-perature boundary lines of 21degC and 25degC exhibited obviousfluctuations there was a high temperature distribution areain the middle position of block while low temperaturedistribution area is close to the block joint proving theexistence of thermal bridge caused by the block jointsHowever because the main heat isolation component is theextruded polystyrene layer the fluctuate depth of temper-ature was limited in the concrete part and no temperatureinfluence reached at the external surface

Tenon composite block Mortar joint

5 390 390 51010

1200

30degC interior temperature

ndash10degC interior temperature

300

390

Figure 12 Simplified heat transfer model of the block wall

Table 6 ermal parameters of test specimens

Specimen ermal resistanceR(m2 middotKW)

ermal conductivityλk (W(mmiddotK))

Heat transfer coefficientK (W(m2 middotK))

Total thermal resistanceRsu(m2 middotKW)

Q-1 1581 0632 0546 1830Q-2 1691 0591 0513 1950Q-3 1765 0567 0497 2010

Table 7 ermophysical parameters of materials in TCB

Material ermal conductivity (W(mmiddotK)) ickness (mm)Concrete 1178 195Extruded polystyrene layer 0030 65Vertical air interlayer 0746 135Masonry mortar 0930 25

8 Advances in Materials Science and Engineering

Figure 16 is the heat flux density distribution of thetenon connected block wall model in heat steady stage eheat flux density in most of the wall area is very low in-cluding the internal hollow concrete part the extrudedpolystyrene layer and the external concrete part whichindicated that the extruded polystyrene layer and the airinsulation layer effectively prevent heat transmissionHowever a very high heat flux density distributed at theblock joints which proved the same phenomenon of thethermal bridge in Figure 15

Concluding the temperature and heat flux density dis-tribution in Figures 15 and 16 the extruded polystyrenelayer contributed very reliable and continuous thermal

insulation performance which contributed to the staggeredarranged tenon avoiding the thickness reduction of extrudedpolystyrene layer is also proved the reasonability of thestaggered arranged tenon in this new TCB Apart from thereasonably arranged tenon the block joint still inevitablybecomes the heat bridge of tenon composite thermalinsulation wall and further study on avoiding heat bridge ofblock joint should be focused

6 Conclusion

e main conclusions obtained from the experimentaltesting and numerical simulation are as follows

Figure 13 Geometric model of the thermal analysis unit

Figure 14 Grid diagram of the thermal analysis unit

ndash10 ndash111111 777778 166667 25555630211111122222333333ndash555556

Figure 15 Cloud pattern of wall temperature distribution

122015 808705 160521 240171 319822410453 120696 200346 279997 359647

Figure 16 Distribution of heat flux density in the wall

Table 8 Total thermal resistance of the block wall in the experimental test and numerical simulation

Condition Total thermal resistance Ru (m2 middotK)W Relevant error

Experiment 2010 61Numerical simulation 2133

Advances in Materials Science and Engineering 9

(1) e experimental strength test of the blocks with threedifferent mixing ratios which were proposed by earlyexperimental test experiences and optimizationproved that the mixing ratios were reliable to supplyhigher strength than the design code required strength

(2) e experimental steady-state thermal test on TCBwall specimens indicated that the TCB wall specimenhas good thermal performance when compared tothe total thermal resistance with the common blockwall

(3) Experimental results from the thermal test and themechanical test proved that the A mixing ratio blockhad better thermal performance which contributesto the mechanical sand and stone powder percent-ages while very close strength to that of B mixingratio block erefore it is suggested that the opti-mized A mixing ratio can be used in the TCBproduction

(4) e numerical simulation provided acceptable andaccurate results with a low relative error e nu-merical simulation results proved the reasonabilityof the staggered arranged tenon to avoid thermalperformance reduction But the inevitable thermalbridge existed at the block joints and should befocused in further study

Nomenclature

Basic UnitsK Kelvin temperatureMPa Mega Pascalm Metermm MillimeterW Watts SeconddegC Celsius temperatureLatin and Greek lettersA Face area of specimen (m2)

K Heat transfer coefficient (W(m2 middotK))

M3 Heat flux coefficient of external wall of measuring heatbox (WK)

Q1 Heat flux rate (W)

R ermal resistance (m2 middotKW)

Rsu Total thermal resistance (m2 middotKW)

δ Specimen thickness (m)

λk ermal conductivity (W(mmiddotK))

AcronymsCO2 Carbon dioxideTCB Tenon composite block

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

is work was supported by the Science Project of JiangsuWater Conservancy Bureau (Grant no 2016038) the SocialDevelopment Project of Nanjing Science and TechnologyCommission Fund Programs (Grant no 201505018) and theNational Natural Science Foundation for Young Scientists ofChina (Grant no 51708260)

References

[1] A N Raut and C P Gomez ldquoAssessment of thermal andenergy performance of thermally efficient sustainable wallsystem for Malaysian low cost housingrdquo Applied -ermalEngineering vol 136 pp 309ndash318 2018

[2] G Vasconcelos P Lourenco P Mendonca et al ldquoProposal ofan innovative solution for partition walls mechanical ther-mal and acoustic validationrdquo Construction and BuildingMaterials vol 48 pp 961ndash979 2013

[3] R D Diao L Z Sun and F Yang ldquoermal performance ofbuilding wall materials in villages and towns in hot summerand cold winter zone in Chinardquo Applied-ermal Engineeringvol 128 pp 517ndash530 2018

[4] V Echarri-Iribarren C Rizo-Maestre and F Echarri-Iri-barren ldquoHealthy climate and energy savings using thermalceramic panels and solar thermal panels in mediterraneanhousing blocksrdquo Energies vol 11 no 10 2018

[5] M Fogiatto G Santos and J Catelan ldquoNumerical two-di-mensional steady-state evaluation of the thermal trans-mittance reduction in hollow blocksrdquo Energies vol 12 no 3p 449 2019

[6] E Wati P Meukam and J C Damfeu ldquoModeling thermalperformance of exterior walls retrofitted from insulation andmodified laterite based bricks materialsrdquo Heat and MassTransfer vol 53 no 12 pp 3487ndash3499 2017

[7] A Laaouatni N Martaj R Bennacer M Lachi M El Omariand M El Ganaoui ldquoermal building control using activeventilated block integrating phase change materialrdquo Energyand Buildings vol 187 pp 50ndash63 2019

[8] J Wu G L Bai P Wang and Y Liu ldquoMechanical propertiesof a new type of block made from shale and coal ganguerdquoConstruction and Building Materials vol 190 pp 796ndash8042018

[9] M X Xiong Y H Wang and J Y R Liew ldquoEvaluation onthermal behaviour of concrete-filled steel tubular columnsbased on modified finite difference methodrdquo Advances inStructural Engineering vol 19 no 5 pp 746ndash761 2016

[10] D Y Wu S T Liang M Y Shen Z X Guo X J Zhu andC F Sun ldquoExperimental estimation of seismic properties ofnew precast shear wall spatial structure modelrdquo EngineeringStructures vol 183 pp 319ndash339 2019

[11] D Y Wu S T Liang M Y Shen et al ldquoFinite-elementsimulation on NPGCS precast shear wall spatial structuremodelrdquo Advances in Civil Engineering vol 2019 Article ID2647891 17 pages 2019

[12] S Noor-E-Khuda and F Albermani ldquoMechanical propertiesof clay masonry units destructive and ultrasonic testingrdquoConstruction and Building Materials vol 219 pp 111ndash1202019

[13] I Gnip S Vejelis and S Vaitkus ldquoermal conductivity ofexpanded polystyrene (EPS) at 10 degrees C and its con-version to temperatures within interval from 0 to 50 degreesCrdquo Energy and Buildings vol 52 pp 107ndash111 2012

10 Advances in Materials Science and Engineering

[14] T eodosiou K Tsikaloudaki S Tsoka and P Chastasldquoermal bridging problems on advanced cladding systemsand smart building facadesrdquo Journal of Cleaner Productionvol 214 pp 62ndash69 2019

[15] P Brzyski M Grudzinska and D Majerek ldquoAnalysis of theoccurrence of thermal bridges in several variants of con-nections of the wall and the ground floor in constructionTechnology with the use of a hemp-lime compositerdquo Mate-rials vol 12 no 15 2019

[16] M Khoukhi ldquoe combined effect of heat and moisturetransfer dependent thermal conductivity of polystyreneinsulation material impact on building energy performancerdquoEnergy and Buildings vol 169 pp 228ndash235 2018

[17] GBT13475-2008 Building Element-Determination of Steady-State -ermal Transmission PropertiesndashCalibrated andGuarded Hot Box China Architecture amp Building PressBeijing China 2008

[18] GBT4111-2013 Test Methods for the Concrete Block andBrick China Architecture amp Building Press Beijing China2013

[19] GB50003-2011 Code for Design of Masonry Structures ChinaArchitecture amp Building Press Beijing China 2011

[20] H Yang X Xu W Xu and I Neumann ldquoTerrestrial laserscanning-based deformation analysis for arch and beamstructuresrdquo IEEE Sensors Journal vol 17 no 14 pp 4605ndash4611 2017

[21] H Yang X Xu and I Neumann ldquoDeformation behavioranalysis of composite structures under monotonic loads basedon terrestrial laser scanning Technologyrdquo Composite Struc-tures vol 183 pp 594ndash599 2017

[22] H Yang X Xu and I Neumann ldquoLaser scanning-basedupdating of a finite-element model for structural healthmonitoringrdquo IEEE Sensors Journal vol 16 no 7 pp 2100ndash2104 2016

[23] V Koci J Koci J Madera et al ldquoermal and hygric as-sessment of an inside-insulated brick wall 2D critical ex-periment and computational analysisrdquo Journal of BuildingPhysics vol 41 no 6 pp 497ndash520 2018

[24] GB 50176-2016 Code for -ermal Design of Civil BuildingChina Architecture amp Building Press Beijing China 2016

Advances in Materials Science and Engineering 11

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

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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

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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

ermal Transmission PropertiesmdashCalibrated and GuardedHot Boxrdquo (GBT13475-2008) in China [17] e maximumsample size for standard WTRZ-1212 is 164mtimes 164m andthe measuring size of the TCB wall specimen is 12mtimes 12me testingmachine is shown in Figure 10e test is based onthe guarding hot-box method which relies on a heat pro-tective box to balance external and internal environments andquantitatively analyze thermal performance with minimizedheat consumption and high accuracy e box is also opti-mized to reduce error by synthetically measuring the heat lossof test instruments e testing machine and specimen inreality are shown in Figure 11

ree TCB wall specimens were tested to compare thethermal performance using different concrete mix pro-portions initial mixing ratio and the A and B mixing ratiose block and wall parameters are shown in Table 4 Table 5shows the initial parameters used for the thermal test

42 -ermal Test Results e three TCB wall specimenswere tested strictly according to the national test standard ofldquoBuilding Element-Determination of Steady-State ermalTransmission PropertiesmdashCalibrated and Guarded HotBoxrdquo (GBT13475-2008) [17] In the test the heating powerQp of the heating machine shown in Figure 12 will becollected Apart from that the temperature difference θ3between the inner wall and the outer wall of shelter inheating part (Figure 12) the hot surface temperature Tsi andthe cool surface temperature Tse of the specimen the airtemperature of protective hot box Tni and the air temper-atures of cool box Tne will be collected among which the Tniand Tne were set to be 30degC and minus 10degC in the test but werestill collected to consider testing errors and to improvetesting accuracy e thermal parameters of the three blockwall specimens can be calculated from the collected data andaccording to equations (1)mdash(5) shown in Table 6 includingthe thermal resistance the thermal conductivity the heattransfer coefficient and the total thermal resistance

Q1 QP minus M3θ3 (1)

R A Tsi minus Tse( 1113857

Q1 (2)

λk δR

(3)

K Q1

A Tni minus Tne( 11138571113858 1113859 (4)

Rsu 1K

(5)

From the thermal parameters in Table 6 the followingconclusions can be drawn

(1) e TCB specimens have good total thermal per-formance when compared the total thermal re-sistance Rsu to the Rsu value of 30m2 middot KW ofcommon block wall in which the block has threerows of heat isolation holes and size of390mmtimes 190mmtimes 190mm e Rsu values of theTCB wall are 610 650 and 670 times of the totalthermal resistance of common block wall for the Q-1the Q-2 and the Q-3 respectively

(2) According to the total thermal resistance Rsu valuesof the three wall specimens of Q-1 Q-2 and Q-3 theheat insulation properties of the TCB walls withmixing ratios A and B are 656 and 984 higherthan that of specimen with the initial mixing ratiorespectively which indicates that the mixing ratioand production processing optimization have im-proved thermal performance As this study con-cluded in Section 2 that the TCB with the initialconcrete mixing ratio had the highest strength of815MPa compared to that of ratios A and B to-gether with the Rsu values differences between Q-1 toQ-2 and Q-3 it can be proved that by the optimi-zation of concrete mixing ratio the thermal per-formance was improved and the block compressivestrength was reduced Based on the above conclu-sions it is suggested that the two optimized mixingratios and block production process should be usedin TCB production

(3) e total thermal resistance Rsu of the block wall withthe mixing ratio A (Q-2) is 308 lower than that ofthe block wall with mixing ration B (Q-3) meaningthat the heat isolation properties of the mixing ratioA wall are better than that of the mixing ratio B wallAccording to the block compressive strength shownin Table 3 and the results in Section 2 the com-pressive strength of mixing ratio A is less than 5that of mixing ratio B Together with thermal pa-rameters in Table 6 it can be insufficiently provedthat the portion of mechanical sand and stonepowder is the key to control thermal insulation andmechanical performance more mechanical sand canimprove the strength and more stone powder canimprove the thermal insulation performance Butwhen considering there is a difference of 308 inRsubetween the A and B mixing ratios however thetrend is not obvious when considering the 7 dif-ference in the mechanical sand and stone powderpercentages in the A and B mixing ratios e in-fluence of mechanical sand and limestone powder

Table 3 Average compressive strength of blocks (MPa)

Mixing ratio A B A (6months in open air) B (6months in open air) Initial mixing ratioCompressive strength 688 657 741 684 815

6 Advances in Materials Science and Engineering

percentage should be further evaluated based onmore test cases

5 Finite Element Simulation

51 Finite Element Model e thermal analysis module in-tegrated in ANSYS finite element simulation software wasused to simulate the thermal performance of the TCB wall inheated steady state In the thermal simulation of wall

specimen in this study as the wall size is 12mtimes 12mtimes 02mof which the specimen front face sizes are much larger thanthe specimen thickness the heat energy flow simulation willbe simplified to be one-dimensional heat conduction simu-lation on the two-dimensional finite element model whichonly considers the heat energy flow in the thickness directionAnd as the thermal experimental testing was the steady-stateheat transfer performance testing the finite element simu-lation will also assume that the specimen was in steady-stateheat transfer situation Finally the finite element simulationadopted the following three assumptions

(1) Different material parts in TCB including the internalhollow concrete block part the extruded polystyrenelayer and the external block part will be assumed tobe inseparable connected and no material or thermalproperties changes with temperature

(2) e heat energy flow will only be in the thicknessdirection and the simulation will be simplified to beone-dimensional heat conduction simulation

(3) e simulation of the specimen is in the steady-stateheat transfer situation which means the environ-ment temperature of the two sides of the specimenremains constant

Based on the above assumptions and test method[20ndash22] the simulation element for the TCB wall wasselected as PLANE55 which is a two-dimensional thermalsolid element with 4 nodes and can be used as a planar oraxisymmetric element in two-dimensional heat steady-stage and instantaneous-stage analyses [23] e node inthe PLANE55 element only contains one temperaturedegree of freedom

52 Material Properties According to the experimental testresults and the theory of the parallel-series method inequations (1)mdash(5) the thermal conductivity of the concretefor mixing ratio A can be calculated as λk 1178W(mmiddotK)Other thermophysical parameters of related materials usedin the TCB are determined according to the testing standardof ldquoCode for ermal Design of Civil Buildingrdquo (GB 50176-2016) [24] and are shown in Table 7

53 Meshing and Boundary Conditions e finite elementgeometric model was automatically generated by the ANSYS

Specimen frame

ShelterHeating machine

Heat conduction screen

Heat circulating fan

Heat circulating pipeline

Cooling pipeline

Specimen

Cooling screen

Cooling fan

Cooler

Cooling machine

Figure 10 Schematic of the test machine for the joggled joint block wall thermal test

Figure 11 Testing machine in reality

Table 4 Specimen parameters

Specimen Block Size (mm)Q-1 Initial mixing ratio block 390times 300times115Q-2 A mixing ratio block 390times 300times115Q-3 B mixing ratio block 390times 300times115

Table 5 Initial parameters used for the thermal test

Air temperature of experimental heat box 300degCAir temperature of protective hot box 300degCAir temperature of cold box minus 100degCRelative humidity of experimental heat box 30Heat flux coefficient M3 of the external wall ofmeasuring heat box 152WK

Wall thickness 300mm

Advances in Materials Science and Engineering 7

simulation software and the mesh was discretized into atriangle or quadrilateral shape with 5mm mesh sizeCompared with the thermal experimental test results of thewall the interior temperature of the simulated wall was 30degCand the exterior temperature of the wall was minus 10degC efinite element simulation model assumed that the boundaryconditions are complete heat isolation the convective heattransfer is only applied on internal and external surfaceswhich are selected as boundary condition while no heattransfer exists on block connection joints e convectiveheat transfer coefficients of the interior and exterior were87W(m2 middotK) and 230 W(m2 middotK) respectively e sim-plified one-dimensional TCB wall model is shown in Fig-ure 12 e ANSYS geometric model is shown in Figure 13e mesh used for the joggled joint block wall model isshown in Figure 14

54 Simulation Results e finite element simulation cal-culated the temperature distribution and heat flux distribu-tion maps shown in Figures 15 and 16 According to the heatflux distribution map the average heat flux density Q1 can beobtained by ANSYS software And according to Fourierrsquos lawof heat conduction in equation (2) the thermal conductivityvalue can be obtained e relation between specimen totalthermal resistance and thermal conductivity can be obtainedby equation (3)e average thermal performance parametersof the wall specimen are shown in Table 8 By comparing thecalculation results with those obtained in the previous ex-perimental test it can be found that the numerical simulation

thermal resistance of the A mixing ratio block wall is2133(m2 middotK)W which is 61 higher than that obtainedfrom experimental testing of 1950(m2 middotK)W e relativeerror is caused by two reasons (1) the simulation modelassumes that the boundary conditions are complete heatisolation and inconsistent with reality (2) heat loss andmeasurement error are inevitable in the experimental testprocess Comparing the simulation results with the experi-mental results the relative error is low and acceptable

Figure 15 shows the temperature distribution of the TCBwall where it can be seen that the temperature decreasesgradually from the internal surface to the external surfaceHowever the area with the most rapid temperature decreasewas the heat isolation layer Because temperature variationrate is inversely proportional to the thermal conductivityvalue of the material and the thermal conductivity value ofthe extruded polystyrene layer is 0030W(mmiddotK) which is farless than the value of 1178W(mmiddotK) for concrete and0746W(mmiddotK) for air it can be proved that the extrudedpolystyrene layer contributes most of the heat isolationperformance It can be found in Figure 15 that the tem-perature boundary lines of 21degC and 25degC exhibited obviousfluctuations there was a high temperature distribution areain the middle position of block while low temperaturedistribution area is close to the block joint proving theexistence of thermal bridge caused by the block jointsHowever because the main heat isolation component is theextruded polystyrene layer the fluctuate depth of temper-ature was limited in the concrete part and no temperatureinfluence reached at the external surface

Tenon composite block Mortar joint

5 390 390 51010

1200

30degC interior temperature

ndash10degC interior temperature

300

390

Figure 12 Simplified heat transfer model of the block wall

Table 6 ermal parameters of test specimens

Specimen ermal resistanceR(m2 middotKW)

ermal conductivityλk (W(mmiddotK))

Heat transfer coefficientK (W(m2 middotK))

Total thermal resistanceRsu(m2 middotKW)

Q-1 1581 0632 0546 1830Q-2 1691 0591 0513 1950Q-3 1765 0567 0497 2010

Table 7 ermophysical parameters of materials in TCB

Material ermal conductivity (W(mmiddotK)) ickness (mm)Concrete 1178 195Extruded polystyrene layer 0030 65Vertical air interlayer 0746 135Masonry mortar 0930 25

8 Advances in Materials Science and Engineering

Figure 16 is the heat flux density distribution of thetenon connected block wall model in heat steady stage eheat flux density in most of the wall area is very low in-cluding the internal hollow concrete part the extrudedpolystyrene layer and the external concrete part whichindicated that the extruded polystyrene layer and the airinsulation layer effectively prevent heat transmissionHowever a very high heat flux density distributed at theblock joints which proved the same phenomenon of thethermal bridge in Figure 15

Concluding the temperature and heat flux density dis-tribution in Figures 15 and 16 the extruded polystyrenelayer contributed very reliable and continuous thermal

insulation performance which contributed to the staggeredarranged tenon avoiding the thickness reduction of extrudedpolystyrene layer is also proved the reasonability of thestaggered arranged tenon in this new TCB Apart from thereasonably arranged tenon the block joint still inevitablybecomes the heat bridge of tenon composite thermalinsulation wall and further study on avoiding heat bridge ofblock joint should be focused

6 Conclusion

e main conclusions obtained from the experimentaltesting and numerical simulation are as follows

Figure 13 Geometric model of the thermal analysis unit

Figure 14 Grid diagram of the thermal analysis unit

ndash10 ndash111111 777778 166667 25555630211111122222333333ndash555556

Figure 15 Cloud pattern of wall temperature distribution

122015 808705 160521 240171 319822410453 120696 200346 279997 359647

Figure 16 Distribution of heat flux density in the wall

Table 8 Total thermal resistance of the block wall in the experimental test and numerical simulation

Condition Total thermal resistance Ru (m2 middotK)W Relevant error

Experiment 2010 61Numerical simulation 2133

Advances in Materials Science and Engineering 9

(1) e experimental strength test of the blocks with threedifferent mixing ratios which were proposed by earlyexperimental test experiences and optimizationproved that the mixing ratios were reliable to supplyhigher strength than the design code required strength

(2) e experimental steady-state thermal test on TCBwall specimens indicated that the TCB wall specimenhas good thermal performance when compared tothe total thermal resistance with the common blockwall

(3) Experimental results from the thermal test and themechanical test proved that the A mixing ratio blockhad better thermal performance which contributesto the mechanical sand and stone powder percent-ages while very close strength to that of B mixingratio block erefore it is suggested that the opti-mized A mixing ratio can be used in the TCBproduction

(4) e numerical simulation provided acceptable andaccurate results with a low relative error e nu-merical simulation results proved the reasonabilityof the staggered arranged tenon to avoid thermalperformance reduction But the inevitable thermalbridge existed at the block joints and should befocused in further study

Nomenclature

Basic UnitsK Kelvin temperatureMPa Mega Pascalm Metermm MillimeterW Watts SeconddegC Celsius temperatureLatin and Greek lettersA Face area of specimen (m2)

K Heat transfer coefficient (W(m2 middotK))

M3 Heat flux coefficient of external wall of measuring heatbox (WK)

Q1 Heat flux rate (W)

R ermal resistance (m2 middotKW)

Rsu Total thermal resistance (m2 middotKW)

δ Specimen thickness (m)

λk ermal conductivity (W(mmiddotK))

AcronymsCO2 Carbon dioxideTCB Tenon composite block

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

is work was supported by the Science Project of JiangsuWater Conservancy Bureau (Grant no 2016038) the SocialDevelopment Project of Nanjing Science and TechnologyCommission Fund Programs (Grant no 201505018) and theNational Natural Science Foundation for Young Scientists ofChina (Grant no 51708260)

References

[1] A N Raut and C P Gomez ldquoAssessment of thermal andenergy performance of thermally efficient sustainable wallsystem for Malaysian low cost housingrdquo Applied -ermalEngineering vol 136 pp 309ndash318 2018

[2] G Vasconcelos P Lourenco P Mendonca et al ldquoProposal ofan innovative solution for partition walls mechanical ther-mal and acoustic validationrdquo Construction and BuildingMaterials vol 48 pp 961ndash979 2013

[3] R D Diao L Z Sun and F Yang ldquoermal performance ofbuilding wall materials in villages and towns in hot summerand cold winter zone in Chinardquo Applied-ermal Engineeringvol 128 pp 517ndash530 2018

[4] V Echarri-Iribarren C Rizo-Maestre and F Echarri-Iri-barren ldquoHealthy climate and energy savings using thermalceramic panels and solar thermal panels in mediterraneanhousing blocksrdquo Energies vol 11 no 10 2018

[5] M Fogiatto G Santos and J Catelan ldquoNumerical two-di-mensional steady-state evaluation of the thermal trans-mittance reduction in hollow blocksrdquo Energies vol 12 no 3p 449 2019

[6] E Wati P Meukam and J C Damfeu ldquoModeling thermalperformance of exterior walls retrofitted from insulation andmodified laterite based bricks materialsrdquo Heat and MassTransfer vol 53 no 12 pp 3487ndash3499 2017

[7] A Laaouatni N Martaj R Bennacer M Lachi M El Omariand M El Ganaoui ldquoermal building control using activeventilated block integrating phase change materialrdquo Energyand Buildings vol 187 pp 50ndash63 2019

[8] J Wu G L Bai P Wang and Y Liu ldquoMechanical propertiesof a new type of block made from shale and coal ganguerdquoConstruction and Building Materials vol 190 pp 796ndash8042018

[9] M X Xiong Y H Wang and J Y R Liew ldquoEvaluation onthermal behaviour of concrete-filled steel tubular columnsbased on modified finite difference methodrdquo Advances inStructural Engineering vol 19 no 5 pp 746ndash761 2016

[10] D Y Wu S T Liang M Y Shen Z X Guo X J Zhu andC F Sun ldquoExperimental estimation of seismic properties ofnew precast shear wall spatial structure modelrdquo EngineeringStructures vol 183 pp 319ndash339 2019

[11] D Y Wu S T Liang M Y Shen et al ldquoFinite-elementsimulation on NPGCS precast shear wall spatial structuremodelrdquo Advances in Civil Engineering vol 2019 Article ID2647891 17 pages 2019

[12] S Noor-E-Khuda and F Albermani ldquoMechanical propertiesof clay masonry units destructive and ultrasonic testingrdquoConstruction and Building Materials vol 219 pp 111ndash1202019

[13] I Gnip S Vejelis and S Vaitkus ldquoermal conductivity ofexpanded polystyrene (EPS) at 10 degrees C and its con-version to temperatures within interval from 0 to 50 degreesCrdquo Energy and Buildings vol 52 pp 107ndash111 2012

10 Advances in Materials Science and Engineering

[14] T eodosiou K Tsikaloudaki S Tsoka and P Chastasldquoermal bridging problems on advanced cladding systemsand smart building facadesrdquo Journal of Cleaner Productionvol 214 pp 62ndash69 2019

[15] P Brzyski M Grudzinska and D Majerek ldquoAnalysis of theoccurrence of thermal bridges in several variants of con-nections of the wall and the ground floor in constructionTechnology with the use of a hemp-lime compositerdquo Mate-rials vol 12 no 15 2019

[16] M Khoukhi ldquoe combined effect of heat and moisturetransfer dependent thermal conductivity of polystyreneinsulation material impact on building energy performancerdquoEnergy and Buildings vol 169 pp 228ndash235 2018

[17] GBT13475-2008 Building Element-Determination of Steady-State -ermal Transmission PropertiesndashCalibrated andGuarded Hot Box China Architecture amp Building PressBeijing China 2008

[18] GBT4111-2013 Test Methods for the Concrete Block andBrick China Architecture amp Building Press Beijing China2013

[19] GB50003-2011 Code for Design of Masonry Structures ChinaArchitecture amp Building Press Beijing China 2011

[20] H Yang X Xu W Xu and I Neumann ldquoTerrestrial laserscanning-based deformation analysis for arch and beamstructuresrdquo IEEE Sensors Journal vol 17 no 14 pp 4605ndash4611 2017

[21] H Yang X Xu and I Neumann ldquoDeformation behavioranalysis of composite structures under monotonic loads basedon terrestrial laser scanning Technologyrdquo Composite Struc-tures vol 183 pp 594ndash599 2017

[22] H Yang X Xu and I Neumann ldquoLaser scanning-basedupdating of a finite-element model for structural healthmonitoringrdquo IEEE Sensors Journal vol 16 no 7 pp 2100ndash2104 2016

[23] V Koci J Koci J Madera et al ldquoermal and hygric as-sessment of an inside-insulated brick wall 2D critical ex-periment and computational analysisrdquo Journal of BuildingPhysics vol 41 no 6 pp 497ndash520 2018

[24] GB 50176-2016 Code for -ermal Design of Civil BuildingChina Architecture amp Building Press Beijing China 2016

Advances in Materials Science and Engineering 11

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

percentage should be further evaluated based onmore test cases

5 Finite Element Simulation

51 Finite Element Model e thermal analysis module in-tegrated in ANSYS finite element simulation software wasused to simulate the thermal performance of the TCB wall inheated steady state In the thermal simulation of wall

specimen in this study as the wall size is 12mtimes 12mtimes 02mof which the specimen front face sizes are much larger thanthe specimen thickness the heat energy flow simulation willbe simplified to be one-dimensional heat conduction simu-lation on the two-dimensional finite element model whichonly considers the heat energy flow in the thickness directionAnd as the thermal experimental testing was the steady-stateheat transfer performance testing the finite element simu-lation will also assume that the specimen was in steady-stateheat transfer situation Finally the finite element simulationadopted the following three assumptions

(1) Different material parts in TCB including the internalhollow concrete block part the extruded polystyrenelayer and the external block part will be assumed tobe inseparable connected and no material or thermalproperties changes with temperature

(2) e heat energy flow will only be in the thicknessdirection and the simulation will be simplified to beone-dimensional heat conduction simulation

(3) e simulation of the specimen is in the steady-stateheat transfer situation which means the environ-ment temperature of the two sides of the specimenremains constant

Based on the above assumptions and test method[20ndash22] the simulation element for the TCB wall wasselected as PLANE55 which is a two-dimensional thermalsolid element with 4 nodes and can be used as a planar oraxisymmetric element in two-dimensional heat steady-stage and instantaneous-stage analyses [23] e node inthe PLANE55 element only contains one temperaturedegree of freedom

52 Material Properties According to the experimental testresults and the theory of the parallel-series method inequations (1)mdash(5) the thermal conductivity of the concretefor mixing ratio A can be calculated as λk 1178W(mmiddotK)Other thermophysical parameters of related materials usedin the TCB are determined according to the testing standardof ldquoCode for ermal Design of Civil Buildingrdquo (GB 50176-2016) [24] and are shown in Table 7

53 Meshing and Boundary Conditions e finite elementgeometric model was automatically generated by the ANSYS

Specimen frame

ShelterHeating machine

Heat conduction screen

Heat circulating fan

Heat circulating pipeline

Cooling pipeline

Specimen

Cooling screen

Cooling fan

Cooler

Cooling machine

Figure 10 Schematic of the test machine for the joggled joint block wall thermal test

Figure 11 Testing machine in reality

Table 4 Specimen parameters

Specimen Block Size (mm)Q-1 Initial mixing ratio block 390times 300times115Q-2 A mixing ratio block 390times 300times115Q-3 B mixing ratio block 390times 300times115

Table 5 Initial parameters used for the thermal test

Air temperature of experimental heat box 300degCAir temperature of protective hot box 300degCAir temperature of cold box minus 100degCRelative humidity of experimental heat box 30Heat flux coefficient M3 of the external wall ofmeasuring heat box 152WK

Wall thickness 300mm

Advances in Materials Science and Engineering 7

simulation software and the mesh was discretized into atriangle or quadrilateral shape with 5mm mesh sizeCompared with the thermal experimental test results of thewall the interior temperature of the simulated wall was 30degCand the exterior temperature of the wall was minus 10degC efinite element simulation model assumed that the boundaryconditions are complete heat isolation the convective heattransfer is only applied on internal and external surfaceswhich are selected as boundary condition while no heattransfer exists on block connection joints e convectiveheat transfer coefficients of the interior and exterior were87W(m2 middotK) and 230 W(m2 middotK) respectively e sim-plified one-dimensional TCB wall model is shown in Fig-ure 12 e ANSYS geometric model is shown in Figure 13e mesh used for the joggled joint block wall model isshown in Figure 14

54 Simulation Results e finite element simulation cal-culated the temperature distribution and heat flux distribu-tion maps shown in Figures 15 and 16 According to the heatflux distribution map the average heat flux density Q1 can beobtained by ANSYS software And according to Fourierrsquos lawof heat conduction in equation (2) the thermal conductivityvalue can be obtained e relation between specimen totalthermal resistance and thermal conductivity can be obtainedby equation (3)e average thermal performance parametersof the wall specimen are shown in Table 8 By comparing thecalculation results with those obtained in the previous ex-perimental test it can be found that the numerical simulation

thermal resistance of the A mixing ratio block wall is2133(m2 middotK)W which is 61 higher than that obtainedfrom experimental testing of 1950(m2 middotK)W e relativeerror is caused by two reasons (1) the simulation modelassumes that the boundary conditions are complete heatisolation and inconsistent with reality (2) heat loss andmeasurement error are inevitable in the experimental testprocess Comparing the simulation results with the experi-mental results the relative error is low and acceptable

Figure 15 shows the temperature distribution of the TCBwall where it can be seen that the temperature decreasesgradually from the internal surface to the external surfaceHowever the area with the most rapid temperature decreasewas the heat isolation layer Because temperature variationrate is inversely proportional to the thermal conductivityvalue of the material and the thermal conductivity value ofthe extruded polystyrene layer is 0030W(mmiddotK) which is farless than the value of 1178W(mmiddotK) for concrete and0746W(mmiddotK) for air it can be proved that the extrudedpolystyrene layer contributes most of the heat isolationperformance It can be found in Figure 15 that the tem-perature boundary lines of 21degC and 25degC exhibited obviousfluctuations there was a high temperature distribution areain the middle position of block while low temperaturedistribution area is close to the block joint proving theexistence of thermal bridge caused by the block jointsHowever because the main heat isolation component is theextruded polystyrene layer the fluctuate depth of temper-ature was limited in the concrete part and no temperatureinfluence reached at the external surface

Tenon composite block Mortar joint

5 390 390 51010

1200

30degC interior temperature

ndash10degC interior temperature

300

390

Figure 12 Simplified heat transfer model of the block wall

Table 6 ermal parameters of test specimens

Specimen ermal resistanceR(m2 middotKW)

ermal conductivityλk (W(mmiddotK))

Heat transfer coefficientK (W(m2 middotK))

Total thermal resistanceRsu(m2 middotKW)

Q-1 1581 0632 0546 1830Q-2 1691 0591 0513 1950Q-3 1765 0567 0497 2010

Table 7 ermophysical parameters of materials in TCB

Material ermal conductivity (W(mmiddotK)) ickness (mm)Concrete 1178 195Extruded polystyrene layer 0030 65Vertical air interlayer 0746 135Masonry mortar 0930 25

8 Advances in Materials Science and Engineering

Figure 16 is the heat flux density distribution of thetenon connected block wall model in heat steady stage eheat flux density in most of the wall area is very low in-cluding the internal hollow concrete part the extrudedpolystyrene layer and the external concrete part whichindicated that the extruded polystyrene layer and the airinsulation layer effectively prevent heat transmissionHowever a very high heat flux density distributed at theblock joints which proved the same phenomenon of thethermal bridge in Figure 15

Concluding the temperature and heat flux density dis-tribution in Figures 15 and 16 the extruded polystyrenelayer contributed very reliable and continuous thermal

insulation performance which contributed to the staggeredarranged tenon avoiding the thickness reduction of extrudedpolystyrene layer is also proved the reasonability of thestaggered arranged tenon in this new TCB Apart from thereasonably arranged tenon the block joint still inevitablybecomes the heat bridge of tenon composite thermalinsulation wall and further study on avoiding heat bridge ofblock joint should be focused

6 Conclusion

e main conclusions obtained from the experimentaltesting and numerical simulation are as follows

Figure 13 Geometric model of the thermal analysis unit

Figure 14 Grid diagram of the thermal analysis unit

ndash10 ndash111111 777778 166667 25555630211111122222333333ndash555556

Figure 15 Cloud pattern of wall temperature distribution

122015 808705 160521 240171 319822410453 120696 200346 279997 359647

Figure 16 Distribution of heat flux density in the wall

Table 8 Total thermal resistance of the block wall in the experimental test and numerical simulation

Condition Total thermal resistance Ru (m2 middotK)W Relevant error

Experiment 2010 61Numerical simulation 2133

Advances in Materials Science and Engineering 9

(1) e experimental strength test of the blocks with threedifferent mixing ratios which were proposed by earlyexperimental test experiences and optimizationproved that the mixing ratios were reliable to supplyhigher strength than the design code required strength

(2) e experimental steady-state thermal test on TCBwall specimens indicated that the TCB wall specimenhas good thermal performance when compared tothe total thermal resistance with the common blockwall

(3) Experimental results from the thermal test and themechanical test proved that the A mixing ratio blockhad better thermal performance which contributesto the mechanical sand and stone powder percent-ages while very close strength to that of B mixingratio block erefore it is suggested that the opti-mized A mixing ratio can be used in the TCBproduction

(4) e numerical simulation provided acceptable andaccurate results with a low relative error e nu-merical simulation results proved the reasonabilityof the staggered arranged tenon to avoid thermalperformance reduction But the inevitable thermalbridge existed at the block joints and should befocused in further study

Nomenclature

Basic UnitsK Kelvin temperatureMPa Mega Pascalm Metermm MillimeterW Watts SeconddegC Celsius temperatureLatin and Greek lettersA Face area of specimen (m2)

K Heat transfer coefficient (W(m2 middotK))

M3 Heat flux coefficient of external wall of measuring heatbox (WK)

Q1 Heat flux rate (W)

R ermal resistance (m2 middotKW)

Rsu Total thermal resistance (m2 middotKW)

δ Specimen thickness (m)

λk ermal conductivity (W(mmiddotK))

AcronymsCO2 Carbon dioxideTCB Tenon composite block

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

is work was supported by the Science Project of JiangsuWater Conservancy Bureau (Grant no 2016038) the SocialDevelopment Project of Nanjing Science and TechnologyCommission Fund Programs (Grant no 201505018) and theNational Natural Science Foundation for Young Scientists ofChina (Grant no 51708260)

References

[1] A N Raut and C P Gomez ldquoAssessment of thermal andenergy performance of thermally efficient sustainable wallsystem for Malaysian low cost housingrdquo Applied -ermalEngineering vol 136 pp 309ndash318 2018

[2] G Vasconcelos P Lourenco P Mendonca et al ldquoProposal ofan innovative solution for partition walls mechanical ther-mal and acoustic validationrdquo Construction and BuildingMaterials vol 48 pp 961ndash979 2013

[3] R D Diao L Z Sun and F Yang ldquoermal performance ofbuilding wall materials in villages and towns in hot summerand cold winter zone in Chinardquo Applied-ermal Engineeringvol 128 pp 517ndash530 2018

[4] V Echarri-Iribarren C Rizo-Maestre and F Echarri-Iri-barren ldquoHealthy climate and energy savings using thermalceramic panels and solar thermal panels in mediterraneanhousing blocksrdquo Energies vol 11 no 10 2018

[5] M Fogiatto G Santos and J Catelan ldquoNumerical two-di-mensional steady-state evaluation of the thermal trans-mittance reduction in hollow blocksrdquo Energies vol 12 no 3p 449 2019

[6] E Wati P Meukam and J C Damfeu ldquoModeling thermalperformance of exterior walls retrofitted from insulation andmodified laterite based bricks materialsrdquo Heat and MassTransfer vol 53 no 12 pp 3487ndash3499 2017

[7] A Laaouatni N Martaj R Bennacer M Lachi M El Omariand M El Ganaoui ldquoermal building control using activeventilated block integrating phase change materialrdquo Energyand Buildings vol 187 pp 50ndash63 2019

[8] J Wu G L Bai P Wang and Y Liu ldquoMechanical propertiesof a new type of block made from shale and coal ganguerdquoConstruction and Building Materials vol 190 pp 796ndash8042018

[9] M X Xiong Y H Wang and J Y R Liew ldquoEvaluation onthermal behaviour of concrete-filled steel tubular columnsbased on modified finite difference methodrdquo Advances inStructural Engineering vol 19 no 5 pp 746ndash761 2016

[10] D Y Wu S T Liang M Y Shen Z X Guo X J Zhu andC F Sun ldquoExperimental estimation of seismic properties ofnew precast shear wall spatial structure modelrdquo EngineeringStructures vol 183 pp 319ndash339 2019

[11] D Y Wu S T Liang M Y Shen et al ldquoFinite-elementsimulation on NPGCS precast shear wall spatial structuremodelrdquo Advances in Civil Engineering vol 2019 Article ID2647891 17 pages 2019

[12] S Noor-E-Khuda and F Albermani ldquoMechanical propertiesof clay masonry units destructive and ultrasonic testingrdquoConstruction and Building Materials vol 219 pp 111ndash1202019

[13] I Gnip S Vejelis and S Vaitkus ldquoermal conductivity ofexpanded polystyrene (EPS) at 10 degrees C and its con-version to temperatures within interval from 0 to 50 degreesCrdquo Energy and Buildings vol 52 pp 107ndash111 2012

10 Advances in Materials Science and Engineering

[14] T eodosiou K Tsikaloudaki S Tsoka and P Chastasldquoermal bridging problems on advanced cladding systemsand smart building facadesrdquo Journal of Cleaner Productionvol 214 pp 62ndash69 2019

[15] P Brzyski M Grudzinska and D Majerek ldquoAnalysis of theoccurrence of thermal bridges in several variants of con-nections of the wall and the ground floor in constructionTechnology with the use of a hemp-lime compositerdquo Mate-rials vol 12 no 15 2019

[16] M Khoukhi ldquoe combined effect of heat and moisturetransfer dependent thermal conductivity of polystyreneinsulation material impact on building energy performancerdquoEnergy and Buildings vol 169 pp 228ndash235 2018

[17] GBT13475-2008 Building Element-Determination of Steady-State -ermal Transmission PropertiesndashCalibrated andGuarded Hot Box China Architecture amp Building PressBeijing China 2008

[18] GBT4111-2013 Test Methods for the Concrete Block andBrick China Architecture amp Building Press Beijing China2013

[19] GB50003-2011 Code for Design of Masonry Structures ChinaArchitecture amp Building Press Beijing China 2011

[20] H Yang X Xu W Xu and I Neumann ldquoTerrestrial laserscanning-based deformation analysis for arch and beamstructuresrdquo IEEE Sensors Journal vol 17 no 14 pp 4605ndash4611 2017

[21] H Yang X Xu and I Neumann ldquoDeformation behavioranalysis of composite structures under monotonic loads basedon terrestrial laser scanning Technologyrdquo Composite Struc-tures vol 183 pp 594ndash599 2017

[22] H Yang X Xu and I Neumann ldquoLaser scanning-basedupdating of a finite-element model for structural healthmonitoringrdquo IEEE Sensors Journal vol 16 no 7 pp 2100ndash2104 2016

[23] V Koci J Koci J Madera et al ldquoermal and hygric as-sessment of an inside-insulated brick wall 2D critical ex-periment and computational analysisrdquo Journal of BuildingPhysics vol 41 no 6 pp 497ndash520 2018

[24] GB 50176-2016 Code for -ermal Design of Civil BuildingChina Architecture amp Building Press Beijing China 2016

Advances in Materials Science and Engineering 11

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

simulation software and the mesh was discretized into atriangle or quadrilateral shape with 5mm mesh sizeCompared with the thermal experimental test results of thewall the interior temperature of the simulated wall was 30degCand the exterior temperature of the wall was minus 10degC efinite element simulation model assumed that the boundaryconditions are complete heat isolation the convective heattransfer is only applied on internal and external surfaceswhich are selected as boundary condition while no heattransfer exists on block connection joints e convectiveheat transfer coefficients of the interior and exterior were87W(m2 middotK) and 230 W(m2 middotK) respectively e sim-plified one-dimensional TCB wall model is shown in Fig-ure 12 e ANSYS geometric model is shown in Figure 13e mesh used for the joggled joint block wall model isshown in Figure 14

54 Simulation Results e finite element simulation cal-culated the temperature distribution and heat flux distribu-tion maps shown in Figures 15 and 16 According to the heatflux distribution map the average heat flux density Q1 can beobtained by ANSYS software And according to Fourierrsquos lawof heat conduction in equation (2) the thermal conductivityvalue can be obtained e relation between specimen totalthermal resistance and thermal conductivity can be obtainedby equation (3)e average thermal performance parametersof the wall specimen are shown in Table 8 By comparing thecalculation results with those obtained in the previous ex-perimental test it can be found that the numerical simulation

thermal resistance of the A mixing ratio block wall is2133(m2 middotK)W which is 61 higher than that obtainedfrom experimental testing of 1950(m2 middotK)W e relativeerror is caused by two reasons (1) the simulation modelassumes that the boundary conditions are complete heatisolation and inconsistent with reality (2) heat loss andmeasurement error are inevitable in the experimental testprocess Comparing the simulation results with the experi-mental results the relative error is low and acceptable

Figure 15 shows the temperature distribution of the TCBwall where it can be seen that the temperature decreasesgradually from the internal surface to the external surfaceHowever the area with the most rapid temperature decreasewas the heat isolation layer Because temperature variationrate is inversely proportional to the thermal conductivityvalue of the material and the thermal conductivity value ofthe extruded polystyrene layer is 0030W(mmiddotK) which is farless than the value of 1178W(mmiddotK) for concrete and0746W(mmiddotK) for air it can be proved that the extrudedpolystyrene layer contributes most of the heat isolationperformance It can be found in Figure 15 that the tem-perature boundary lines of 21degC and 25degC exhibited obviousfluctuations there was a high temperature distribution areain the middle position of block while low temperaturedistribution area is close to the block joint proving theexistence of thermal bridge caused by the block jointsHowever because the main heat isolation component is theextruded polystyrene layer the fluctuate depth of temper-ature was limited in the concrete part and no temperatureinfluence reached at the external surface

Tenon composite block Mortar joint

5 390 390 51010

1200

30degC interior temperature

ndash10degC interior temperature

300

390

Figure 12 Simplified heat transfer model of the block wall

Table 6 ermal parameters of test specimens

Specimen ermal resistanceR(m2 middotKW)

ermal conductivityλk (W(mmiddotK))

Heat transfer coefficientK (W(m2 middotK))

Total thermal resistanceRsu(m2 middotKW)

Q-1 1581 0632 0546 1830Q-2 1691 0591 0513 1950Q-3 1765 0567 0497 2010

Table 7 ermophysical parameters of materials in TCB

Material ermal conductivity (W(mmiddotK)) ickness (mm)Concrete 1178 195Extruded polystyrene layer 0030 65Vertical air interlayer 0746 135Masonry mortar 0930 25

8 Advances in Materials Science and Engineering

Figure 16 is the heat flux density distribution of thetenon connected block wall model in heat steady stage eheat flux density in most of the wall area is very low in-cluding the internal hollow concrete part the extrudedpolystyrene layer and the external concrete part whichindicated that the extruded polystyrene layer and the airinsulation layer effectively prevent heat transmissionHowever a very high heat flux density distributed at theblock joints which proved the same phenomenon of thethermal bridge in Figure 15

Concluding the temperature and heat flux density dis-tribution in Figures 15 and 16 the extruded polystyrenelayer contributed very reliable and continuous thermal

insulation performance which contributed to the staggeredarranged tenon avoiding the thickness reduction of extrudedpolystyrene layer is also proved the reasonability of thestaggered arranged tenon in this new TCB Apart from thereasonably arranged tenon the block joint still inevitablybecomes the heat bridge of tenon composite thermalinsulation wall and further study on avoiding heat bridge ofblock joint should be focused

6 Conclusion

e main conclusions obtained from the experimentaltesting and numerical simulation are as follows

Figure 13 Geometric model of the thermal analysis unit

Figure 14 Grid diagram of the thermal analysis unit

ndash10 ndash111111 777778 166667 25555630211111122222333333ndash555556

Figure 15 Cloud pattern of wall temperature distribution

122015 808705 160521 240171 319822410453 120696 200346 279997 359647

Figure 16 Distribution of heat flux density in the wall

Table 8 Total thermal resistance of the block wall in the experimental test and numerical simulation

Condition Total thermal resistance Ru (m2 middotK)W Relevant error

Experiment 2010 61Numerical simulation 2133

Advances in Materials Science and Engineering 9

(1) e experimental strength test of the blocks with threedifferent mixing ratios which were proposed by earlyexperimental test experiences and optimizationproved that the mixing ratios were reliable to supplyhigher strength than the design code required strength

(2) e experimental steady-state thermal test on TCBwall specimens indicated that the TCB wall specimenhas good thermal performance when compared tothe total thermal resistance with the common blockwall

(3) Experimental results from the thermal test and themechanical test proved that the A mixing ratio blockhad better thermal performance which contributesto the mechanical sand and stone powder percent-ages while very close strength to that of B mixingratio block erefore it is suggested that the opti-mized A mixing ratio can be used in the TCBproduction

(4) e numerical simulation provided acceptable andaccurate results with a low relative error e nu-merical simulation results proved the reasonabilityof the staggered arranged tenon to avoid thermalperformance reduction But the inevitable thermalbridge existed at the block joints and should befocused in further study

Nomenclature

Basic UnitsK Kelvin temperatureMPa Mega Pascalm Metermm MillimeterW Watts SeconddegC Celsius temperatureLatin and Greek lettersA Face area of specimen (m2)

K Heat transfer coefficient (W(m2 middotK))

M3 Heat flux coefficient of external wall of measuring heatbox (WK)

Q1 Heat flux rate (W)

R ermal resistance (m2 middotKW)

Rsu Total thermal resistance (m2 middotKW)

δ Specimen thickness (m)

λk ermal conductivity (W(mmiddotK))

AcronymsCO2 Carbon dioxideTCB Tenon composite block

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

is work was supported by the Science Project of JiangsuWater Conservancy Bureau (Grant no 2016038) the SocialDevelopment Project of Nanjing Science and TechnologyCommission Fund Programs (Grant no 201505018) and theNational Natural Science Foundation for Young Scientists ofChina (Grant no 51708260)

References

[1] A N Raut and C P Gomez ldquoAssessment of thermal andenergy performance of thermally efficient sustainable wallsystem for Malaysian low cost housingrdquo Applied -ermalEngineering vol 136 pp 309ndash318 2018

[2] G Vasconcelos P Lourenco P Mendonca et al ldquoProposal ofan innovative solution for partition walls mechanical ther-mal and acoustic validationrdquo Construction and BuildingMaterials vol 48 pp 961ndash979 2013

[3] R D Diao L Z Sun and F Yang ldquoermal performance ofbuilding wall materials in villages and towns in hot summerand cold winter zone in Chinardquo Applied-ermal Engineeringvol 128 pp 517ndash530 2018

[4] V Echarri-Iribarren C Rizo-Maestre and F Echarri-Iri-barren ldquoHealthy climate and energy savings using thermalceramic panels and solar thermal panels in mediterraneanhousing blocksrdquo Energies vol 11 no 10 2018

[5] M Fogiatto G Santos and J Catelan ldquoNumerical two-di-mensional steady-state evaluation of the thermal trans-mittance reduction in hollow blocksrdquo Energies vol 12 no 3p 449 2019

[6] E Wati P Meukam and J C Damfeu ldquoModeling thermalperformance of exterior walls retrofitted from insulation andmodified laterite based bricks materialsrdquo Heat and MassTransfer vol 53 no 12 pp 3487ndash3499 2017

[7] A Laaouatni N Martaj R Bennacer M Lachi M El Omariand M El Ganaoui ldquoermal building control using activeventilated block integrating phase change materialrdquo Energyand Buildings vol 187 pp 50ndash63 2019

[8] J Wu G L Bai P Wang and Y Liu ldquoMechanical propertiesof a new type of block made from shale and coal ganguerdquoConstruction and Building Materials vol 190 pp 796ndash8042018

[9] M X Xiong Y H Wang and J Y R Liew ldquoEvaluation onthermal behaviour of concrete-filled steel tubular columnsbased on modified finite difference methodrdquo Advances inStructural Engineering vol 19 no 5 pp 746ndash761 2016

[10] D Y Wu S T Liang M Y Shen Z X Guo X J Zhu andC F Sun ldquoExperimental estimation of seismic properties ofnew precast shear wall spatial structure modelrdquo EngineeringStructures vol 183 pp 319ndash339 2019

[11] D Y Wu S T Liang M Y Shen et al ldquoFinite-elementsimulation on NPGCS precast shear wall spatial structuremodelrdquo Advances in Civil Engineering vol 2019 Article ID2647891 17 pages 2019

[12] S Noor-E-Khuda and F Albermani ldquoMechanical propertiesof clay masonry units destructive and ultrasonic testingrdquoConstruction and Building Materials vol 219 pp 111ndash1202019

[13] I Gnip S Vejelis and S Vaitkus ldquoermal conductivity ofexpanded polystyrene (EPS) at 10 degrees C and its con-version to temperatures within interval from 0 to 50 degreesCrdquo Energy and Buildings vol 52 pp 107ndash111 2012

10 Advances in Materials Science and Engineering

[14] T eodosiou K Tsikaloudaki S Tsoka and P Chastasldquoermal bridging problems on advanced cladding systemsand smart building facadesrdquo Journal of Cleaner Productionvol 214 pp 62ndash69 2019

[15] P Brzyski M Grudzinska and D Majerek ldquoAnalysis of theoccurrence of thermal bridges in several variants of con-nections of the wall and the ground floor in constructionTechnology with the use of a hemp-lime compositerdquo Mate-rials vol 12 no 15 2019

[16] M Khoukhi ldquoe combined effect of heat and moisturetransfer dependent thermal conductivity of polystyreneinsulation material impact on building energy performancerdquoEnergy and Buildings vol 169 pp 228ndash235 2018

[17] GBT13475-2008 Building Element-Determination of Steady-State -ermal Transmission PropertiesndashCalibrated andGuarded Hot Box China Architecture amp Building PressBeijing China 2008

[18] GBT4111-2013 Test Methods for the Concrete Block andBrick China Architecture amp Building Press Beijing China2013

[19] GB50003-2011 Code for Design of Masonry Structures ChinaArchitecture amp Building Press Beijing China 2011

[20] H Yang X Xu W Xu and I Neumann ldquoTerrestrial laserscanning-based deformation analysis for arch and beamstructuresrdquo IEEE Sensors Journal vol 17 no 14 pp 4605ndash4611 2017

[21] H Yang X Xu and I Neumann ldquoDeformation behavioranalysis of composite structures under monotonic loads basedon terrestrial laser scanning Technologyrdquo Composite Struc-tures vol 183 pp 594ndash599 2017

[22] H Yang X Xu and I Neumann ldquoLaser scanning-basedupdating of a finite-element model for structural healthmonitoringrdquo IEEE Sensors Journal vol 16 no 7 pp 2100ndash2104 2016

[23] V Koci J Koci J Madera et al ldquoermal and hygric as-sessment of an inside-insulated brick wall 2D critical ex-periment and computational analysisrdquo Journal of BuildingPhysics vol 41 no 6 pp 497ndash520 2018

[24] GB 50176-2016 Code for -ermal Design of Civil BuildingChina Architecture amp Building Press Beijing China 2016

Advances in Materials Science and Engineering 11

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 16 is the heat flux density distribution of thetenon connected block wall model in heat steady stage eheat flux density in most of the wall area is very low in-cluding the internal hollow concrete part the extrudedpolystyrene layer and the external concrete part whichindicated that the extruded polystyrene layer and the airinsulation layer effectively prevent heat transmissionHowever a very high heat flux density distributed at theblock joints which proved the same phenomenon of thethermal bridge in Figure 15

Concluding the temperature and heat flux density dis-tribution in Figures 15 and 16 the extruded polystyrenelayer contributed very reliable and continuous thermal

insulation performance which contributed to the staggeredarranged tenon avoiding the thickness reduction of extrudedpolystyrene layer is also proved the reasonability of thestaggered arranged tenon in this new TCB Apart from thereasonably arranged tenon the block joint still inevitablybecomes the heat bridge of tenon composite thermalinsulation wall and further study on avoiding heat bridge ofblock joint should be focused

6 Conclusion

e main conclusions obtained from the experimentaltesting and numerical simulation are as follows

Figure 13 Geometric model of the thermal analysis unit

Figure 14 Grid diagram of the thermal analysis unit

ndash10 ndash111111 777778 166667 25555630211111122222333333ndash555556

Figure 15 Cloud pattern of wall temperature distribution

122015 808705 160521 240171 319822410453 120696 200346 279997 359647

Figure 16 Distribution of heat flux density in the wall

Table 8 Total thermal resistance of the block wall in the experimental test and numerical simulation

Condition Total thermal resistance Ru (m2 middotK)W Relevant error

Experiment 2010 61Numerical simulation 2133

Advances in Materials Science and Engineering 9

(1) e experimental strength test of the blocks with threedifferent mixing ratios which were proposed by earlyexperimental test experiences and optimizationproved that the mixing ratios were reliable to supplyhigher strength than the design code required strength

(2) e experimental steady-state thermal test on TCBwall specimens indicated that the TCB wall specimenhas good thermal performance when compared tothe total thermal resistance with the common blockwall

(3) Experimental results from the thermal test and themechanical test proved that the A mixing ratio blockhad better thermal performance which contributesto the mechanical sand and stone powder percent-ages while very close strength to that of B mixingratio block erefore it is suggested that the opti-mized A mixing ratio can be used in the TCBproduction

(4) e numerical simulation provided acceptable andaccurate results with a low relative error e nu-merical simulation results proved the reasonabilityof the staggered arranged tenon to avoid thermalperformance reduction But the inevitable thermalbridge existed at the block joints and should befocused in further study

Nomenclature

Basic UnitsK Kelvin temperatureMPa Mega Pascalm Metermm MillimeterW Watts SeconddegC Celsius temperatureLatin and Greek lettersA Face area of specimen (m2)

K Heat transfer coefficient (W(m2 middotK))

M3 Heat flux coefficient of external wall of measuring heatbox (WK)

Q1 Heat flux rate (W)

R ermal resistance (m2 middotKW)

Rsu Total thermal resistance (m2 middotKW)

δ Specimen thickness (m)

λk ermal conductivity (W(mmiddotK))

AcronymsCO2 Carbon dioxideTCB Tenon composite block

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

is work was supported by the Science Project of JiangsuWater Conservancy Bureau (Grant no 2016038) the SocialDevelopment Project of Nanjing Science and TechnologyCommission Fund Programs (Grant no 201505018) and theNational Natural Science Foundation for Young Scientists ofChina (Grant no 51708260)

References

[1] A N Raut and C P Gomez ldquoAssessment of thermal andenergy performance of thermally efficient sustainable wallsystem for Malaysian low cost housingrdquo Applied -ermalEngineering vol 136 pp 309ndash318 2018

[2] G Vasconcelos P Lourenco P Mendonca et al ldquoProposal ofan innovative solution for partition walls mechanical ther-mal and acoustic validationrdquo Construction and BuildingMaterials vol 48 pp 961ndash979 2013

[3] R D Diao L Z Sun and F Yang ldquoermal performance ofbuilding wall materials in villages and towns in hot summerand cold winter zone in Chinardquo Applied-ermal Engineeringvol 128 pp 517ndash530 2018

[4] V Echarri-Iribarren C Rizo-Maestre and F Echarri-Iri-barren ldquoHealthy climate and energy savings using thermalceramic panels and solar thermal panels in mediterraneanhousing blocksrdquo Energies vol 11 no 10 2018

[5] M Fogiatto G Santos and J Catelan ldquoNumerical two-di-mensional steady-state evaluation of the thermal trans-mittance reduction in hollow blocksrdquo Energies vol 12 no 3p 449 2019

[6] E Wati P Meukam and J C Damfeu ldquoModeling thermalperformance of exterior walls retrofitted from insulation andmodified laterite based bricks materialsrdquo Heat and MassTransfer vol 53 no 12 pp 3487ndash3499 2017

[7] A Laaouatni N Martaj R Bennacer M Lachi M El Omariand M El Ganaoui ldquoermal building control using activeventilated block integrating phase change materialrdquo Energyand Buildings vol 187 pp 50ndash63 2019

[8] J Wu G L Bai P Wang and Y Liu ldquoMechanical propertiesof a new type of block made from shale and coal ganguerdquoConstruction and Building Materials vol 190 pp 796ndash8042018

[9] M X Xiong Y H Wang and J Y R Liew ldquoEvaluation onthermal behaviour of concrete-filled steel tubular columnsbased on modified finite difference methodrdquo Advances inStructural Engineering vol 19 no 5 pp 746ndash761 2016

[10] D Y Wu S T Liang M Y Shen Z X Guo X J Zhu andC F Sun ldquoExperimental estimation of seismic properties ofnew precast shear wall spatial structure modelrdquo EngineeringStructures vol 183 pp 319ndash339 2019

[11] D Y Wu S T Liang M Y Shen et al ldquoFinite-elementsimulation on NPGCS precast shear wall spatial structuremodelrdquo Advances in Civil Engineering vol 2019 Article ID2647891 17 pages 2019

[12] S Noor-E-Khuda and F Albermani ldquoMechanical propertiesof clay masonry units destructive and ultrasonic testingrdquoConstruction and Building Materials vol 219 pp 111ndash1202019

[13] I Gnip S Vejelis and S Vaitkus ldquoermal conductivity ofexpanded polystyrene (EPS) at 10 degrees C and its con-version to temperatures within interval from 0 to 50 degreesCrdquo Energy and Buildings vol 52 pp 107ndash111 2012

10 Advances in Materials Science and Engineering

[14] T eodosiou K Tsikaloudaki S Tsoka and P Chastasldquoermal bridging problems on advanced cladding systemsand smart building facadesrdquo Journal of Cleaner Productionvol 214 pp 62ndash69 2019

[15] P Brzyski M Grudzinska and D Majerek ldquoAnalysis of theoccurrence of thermal bridges in several variants of con-nections of the wall and the ground floor in constructionTechnology with the use of a hemp-lime compositerdquo Mate-rials vol 12 no 15 2019

[16] M Khoukhi ldquoe combined effect of heat and moisturetransfer dependent thermal conductivity of polystyreneinsulation material impact on building energy performancerdquoEnergy and Buildings vol 169 pp 228ndash235 2018

[17] GBT13475-2008 Building Element-Determination of Steady-State -ermal Transmission PropertiesndashCalibrated andGuarded Hot Box China Architecture amp Building PressBeijing China 2008

[18] GBT4111-2013 Test Methods for the Concrete Block andBrick China Architecture amp Building Press Beijing China2013

[19] GB50003-2011 Code for Design of Masonry Structures ChinaArchitecture amp Building Press Beijing China 2011

[20] H Yang X Xu W Xu and I Neumann ldquoTerrestrial laserscanning-based deformation analysis for arch and beamstructuresrdquo IEEE Sensors Journal vol 17 no 14 pp 4605ndash4611 2017

[21] H Yang X Xu and I Neumann ldquoDeformation behavioranalysis of composite structures under monotonic loads basedon terrestrial laser scanning Technologyrdquo Composite Struc-tures vol 183 pp 594ndash599 2017

[22] H Yang X Xu and I Neumann ldquoLaser scanning-basedupdating of a finite-element model for structural healthmonitoringrdquo IEEE Sensors Journal vol 16 no 7 pp 2100ndash2104 2016

[23] V Koci J Koci J Madera et al ldquoermal and hygric as-sessment of an inside-insulated brick wall 2D critical ex-periment and computational analysisrdquo Journal of BuildingPhysics vol 41 no 6 pp 497ndash520 2018

[24] GB 50176-2016 Code for -ermal Design of Civil BuildingChina Architecture amp Building Press Beijing China 2016

Advances in Materials Science and Engineering 11

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

(1) e experimental strength test of the blocks with threedifferent mixing ratios which were proposed by earlyexperimental test experiences and optimizationproved that the mixing ratios were reliable to supplyhigher strength than the design code required strength

(2) e experimental steady-state thermal test on TCBwall specimens indicated that the TCB wall specimenhas good thermal performance when compared tothe total thermal resistance with the common blockwall

(3) Experimental results from the thermal test and themechanical test proved that the A mixing ratio blockhad better thermal performance which contributesto the mechanical sand and stone powder percent-ages while very close strength to that of B mixingratio block erefore it is suggested that the opti-mized A mixing ratio can be used in the TCBproduction

(4) e numerical simulation provided acceptable andaccurate results with a low relative error e nu-merical simulation results proved the reasonabilityof the staggered arranged tenon to avoid thermalperformance reduction But the inevitable thermalbridge existed at the block joints and should befocused in further study

Nomenclature

Basic UnitsK Kelvin temperatureMPa Mega Pascalm Metermm MillimeterW Watts SeconddegC Celsius temperatureLatin and Greek lettersA Face area of specimen (m2)

K Heat transfer coefficient (W(m2 middotK))

M3 Heat flux coefficient of external wall of measuring heatbox (WK)

Q1 Heat flux rate (W)

R ermal resistance (m2 middotKW)

Rsu Total thermal resistance (m2 middotKW)

δ Specimen thickness (m)

λk ermal conductivity (W(mmiddotK))

AcronymsCO2 Carbon dioxideTCB Tenon composite block

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

is work was supported by the Science Project of JiangsuWater Conservancy Bureau (Grant no 2016038) the SocialDevelopment Project of Nanjing Science and TechnologyCommission Fund Programs (Grant no 201505018) and theNational Natural Science Foundation for Young Scientists ofChina (Grant no 51708260)

References

[1] A N Raut and C P Gomez ldquoAssessment of thermal andenergy performance of thermally efficient sustainable wallsystem for Malaysian low cost housingrdquo Applied -ermalEngineering vol 136 pp 309ndash318 2018

[2] G Vasconcelos P Lourenco P Mendonca et al ldquoProposal ofan innovative solution for partition walls mechanical ther-mal and acoustic validationrdquo Construction and BuildingMaterials vol 48 pp 961ndash979 2013

[3] R D Diao L Z Sun and F Yang ldquoermal performance ofbuilding wall materials in villages and towns in hot summerand cold winter zone in Chinardquo Applied-ermal Engineeringvol 128 pp 517ndash530 2018

[4] V Echarri-Iribarren C Rizo-Maestre and F Echarri-Iri-barren ldquoHealthy climate and energy savings using thermalceramic panels and solar thermal panels in mediterraneanhousing blocksrdquo Energies vol 11 no 10 2018

[5] M Fogiatto G Santos and J Catelan ldquoNumerical two-di-mensional steady-state evaluation of the thermal trans-mittance reduction in hollow blocksrdquo Energies vol 12 no 3p 449 2019

[6] E Wati P Meukam and J C Damfeu ldquoModeling thermalperformance of exterior walls retrofitted from insulation andmodified laterite based bricks materialsrdquo Heat and MassTransfer vol 53 no 12 pp 3487ndash3499 2017

[7] A Laaouatni N Martaj R Bennacer M Lachi M El Omariand M El Ganaoui ldquoermal building control using activeventilated block integrating phase change materialrdquo Energyand Buildings vol 187 pp 50ndash63 2019

[8] J Wu G L Bai P Wang and Y Liu ldquoMechanical propertiesof a new type of block made from shale and coal ganguerdquoConstruction and Building Materials vol 190 pp 796ndash8042018

[9] M X Xiong Y H Wang and J Y R Liew ldquoEvaluation onthermal behaviour of concrete-filled steel tubular columnsbased on modified finite difference methodrdquo Advances inStructural Engineering vol 19 no 5 pp 746ndash761 2016

[10] D Y Wu S T Liang M Y Shen Z X Guo X J Zhu andC F Sun ldquoExperimental estimation of seismic properties ofnew precast shear wall spatial structure modelrdquo EngineeringStructures vol 183 pp 319ndash339 2019

[11] D Y Wu S T Liang M Y Shen et al ldquoFinite-elementsimulation on NPGCS precast shear wall spatial structuremodelrdquo Advances in Civil Engineering vol 2019 Article ID2647891 17 pages 2019

[12] S Noor-E-Khuda and F Albermani ldquoMechanical propertiesof clay masonry units destructive and ultrasonic testingrdquoConstruction and Building Materials vol 219 pp 111ndash1202019

[13] I Gnip S Vejelis and S Vaitkus ldquoermal conductivity ofexpanded polystyrene (EPS) at 10 degrees C and its con-version to temperatures within interval from 0 to 50 degreesCrdquo Energy and Buildings vol 52 pp 107ndash111 2012

10 Advances in Materials Science and Engineering

[14] T eodosiou K Tsikaloudaki S Tsoka and P Chastasldquoermal bridging problems on advanced cladding systemsand smart building facadesrdquo Journal of Cleaner Productionvol 214 pp 62ndash69 2019

[15] P Brzyski M Grudzinska and D Majerek ldquoAnalysis of theoccurrence of thermal bridges in several variants of con-nections of the wall and the ground floor in constructionTechnology with the use of a hemp-lime compositerdquo Mate-rials vol 12 no 15 2019

[16] M Khoukhi ldquoe combined effect of heat and moisturetransfer dependent thermal conductivity of polystyreneinsulation material impact on building energy performancerdquoEnergy and Buildings vol 169 pp 228ndash235 2018

[17] GBT13475-2008 Building Element-Determination of Steady-State -ermal Transmission PropertiesndashCalibrated andGuarded Hot Box China Architecture amp Building PressBeijing China 2008

[18] GBT4111-2013 Test Methods for the Concrete Block andBrick China Architecture amp Building Press Beijing China2013

[19] GB50003-2011 Code for Design of Masonry Structures ChinaArchitecture amp Building Press Beijing China 2011

[20] H Yang X Xu W Xu and I Neumann ldquoTerrestrial laserscanning-based deformation analysis for arch and beamstructuresrdquo IEEE Sensors Journal vol 17 no 14 pp 4605ndash4611 2017

[21] H Yang X Xu and I Neumann ldquoDeformation behavioranalysis of composite structures under monotonic loads basedon terrestrial laser scanning Technologyrdquo Composite Struc-tures vol 183 pp 594ndash599 2017

[22] H Yang X Xu and I Neumann ldquoLaser scanning-basedupdating of a finite-element model for structural healthmonitoringrdquo IEEE Sensors Journal vol 16 no 7 pp 2100ndash2104 2016

[23] V Koci J Koci J Madera et al ldquoermal and hygric as-sessment of an inside-insulated brick wall 2D critical ex-periment and computational analysisrdquo Journal of BuildingPhysics vol 41 no 6 pp 497ndash520 2018

[24] GB 50176-2016 Code for -ermal Design of Civil BuildingChina Architecture amp Building Press Beijing China 2016

Advances in Materials Science and Engineering 11

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

[14] T eodosiou K Tsikaloudaki S Tsoka and P Chastasldquoermal bridging problems on advanced cladding systemsand smart building facadesrdquo Journal of Cleaner Productionvol 214 pp 62ndash69 2019

[15] P Brzyski M Grudzinska and D Majerek ldquoAnalysis of theoccurrence of thermal bridges in several variants of con-nections of the wall and the ground floor in constructionTechnology with the use of a hemp-lime compositerdquo Mate-rials vol 12 no 15 2019

[16] M Khoukhi ldquoe combined effect of heat and moisturetransfer dependent thermal conductivity of polystyreneinsulation material impact on building energy performancerdquoEnergy and Buildings vol 169 pp 228ndash235 2018

[17] GBT13475-2008 Building Element-Determination of Steady-State -ermal Transmission PropertiesndashCalibrated andGuarded Hot Box China Architecture amp Building PressBeijing China 2008

[18] GBT4111-2013 Test Methods for the Concrete Block andBrick China Architecture amp Building Press Beijing China2013

[19] GB50003-2011 Code for Design of Masonry Structures ChinaArchitecture amp Building Press Beijing China 2011

[20] H Yang X Xu W Xu and I Neumann ldquoTerrestrial laserscanning-based deformation analysis for arch and beamstructuresrdquo IEEE Sensors Journal vol 17 no 14 pp 4605ndash4611 2017

[21] H Yang X Xu and I Neumann ldquoDeformation behavioranalysis of composite structures under monotonic loads basedon terrestrial laser scanning Technologyrdquo Composite Struc-tures vol 183 pp 594ndash599 2017

[22] H Yang X Xu and I Neumann ldquoLaser scanning-basedupdating of a finite-element model for structural healthmonitoringrdquo IEEE Sensors Journal vol 16 no 7 pp 2100ndash2104 2016

[23] V Koci J Koci J Madera et al ldquoermal and hygric as-sessment of an inside-insulated brick wall 2D critical ex-periment and computational analysisrdquo Journal of BuildingPhysics vol 41 no 6 pp 497ndash520 2018

[24] GB 50176-2016 Code for -ermal Design of Civil BuildingChina Architecture amp Building Press Beijing China 2016

Advances in Materials Science and Engineering 11

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