Journal of Scientific & Industrial ResearchVol. 65, September 2006, pp. 729-743

Development of bitumen emulsion based cold mix technology for construction ofroads under different climatic conditions of India

N K S Pundhir* and P K NundaCentral Road Research Institute (CRRI). New Delhi 110020

Received 22 August 2005; accepted /5 May 2006

To develop environment and ceo-friendly cold mix technology, lield trials were conducted using bitumen emulsion onJammu-Srinagar Highway NH-IA near Patnitop (J&K) under snow bound arc a, Jowai-Badarpur Road NH-44 near Silchar(Assam) under heavy rainfall and H-S Road near Hanumangarh (Rajasthan) under desert climate. Specifications adoptedwere 25 mm semi dense bituminous concrete (SDBC) and 20 mm premix carpet (PM C) for laying test sections with bitumenemulsion and control section with paving bitumen 80/100. Laboratory mix dcsign for SDBC with bitun]~n emulsion wasdeveloped using Marshall method. Marshall specimens or cold mix were prepared, cured at 40°C for 3 days and tested at25°C for stability and llow value. Post construction performance evaluation has been carried out at 6-month 'iritervals Ior 5-6years. SDBC and PMC with bitumen emulsion performed better or comparable with that of conventional paving gradebitumen. Due to low viscosity. bitumen emulsion penetrated into cracks and helped in sealing them during tack coaling.which resulted into retardation of reflective cracks on overlays. Performance of SDBC with bitumen emulsion was alsofound comparable with that of paving grade bitumen.

Keywords: Bitumen emulsion, Curing, Marshal cold mix design, Pavement distress, StabilityWC Code: EOIC7118

IntroductionB itumi nous road construction with conventional

paving grades bitumen is not desirable in high rainfallareas as intermittent rain throughout the year affectproduction and laying of mixes, and at high attitude orsnow-bound areas as very low pavement temperaturerestrict the laying of hot rnix'". Use of bitumenemulsion eliminates heating of binder and aggregateand thus prevents 'degradation of environment andconserve the energy". Bitumen emulsions are usedworldwides for different applications in roadconstruction due to elimination of heat of binder andaggregate while producing mixes, coating of dampaggregate, protection· of environment and energyconservation. Use of bitumen emulsion in India is veryless (2.7%) as compared to higher consumption (up to43%) in Switzerland, France and other Europeancountries. This may be due to the inexperience in thistechnology, non-availability of proper machinery andlack of quality bitumen emulsions.

Existing construction specifications, IRC: 97-1987(recently revised), IRC: 96-1987, IRC: 100-1988

"Author for correspondenceTcl: +91-11-26832173; Fax: +91-11-26845943E-mail: pundir.crri Onic.in

: .. !

, .: ,~ j

and MOST- 2001 using bitumen emulsion in India arelimited, tentative, and need upgradation. This S,ludyaims: i) To develop emulsion based cold mix design(CMD) for different bituminous surfacing for roadconstruction in different climatic conditions; ii). Toevaluate performance of bitumen emulsions; iii) Tofamiliarize concept of road construction with bitumenemulsion; and iv) To frame specifications andguidelines for design, construction and quality controlfor semi-dense bituminous concrete (SDBC) andpremix carpet (PMC).

Test Locations and Pre-Construction Road ConditionsThree areas (snow bound, high rainfall and desert)

were selected as follows:

Snow Bound Area: Jammu- Srinagar National Highway (NH-lA)

The area beyond Kurd to Patnitop and onward toSri nagar is snow-bound. A stretch of road from km113.800 to km 114.200 near Patnitop was selected forlaying test sections. Heavy trucks and militaryarmoured vehicles are plying on the road. Traffic asreported in 1991 was 1663 commercial vehicles perday (CVPD). The laboratory CBR value of sub gradesoil compacted at field moisture content, field densityand soaked for four days was found 3 %. Traffic

Aggregate Characterisation-Aggregates suppliedby 35 Boarder Roads Task Force (BRTF) Udharnpur(J&K), 36 BRTF Silchar (Assam) and 49 BRTFHanurnangarh (Rajasthan) were subjected to sieveanalysis and tested as per IS: 2386. Properties ofaggregates has been found as: specific gravity,aggregate (11.2 mrn size), 2.63; stone dust, 2.71;aggregate Impact Value, 17; and water absorptionvalue, 0.9%. The typical gradation of aggregates of 35BRTF is given in Table 1.

Testing of' Bitumen Eniulsion-Szttvoses of bitumenemulsion used in construction of test sections weresupplied by IOC R&D Centre and evaluated as per IS:8887-1995. The coating test of aggregates suitabilitywas also carried out as per ASTM: D-2397 orAASHTO: M208. The test results of bitumenemulsion of medium setting (MS) and slow setting(55) grades are given in Table· 2.

Optimization of Premixing Water Content-Peeoptimum water content for premixing, the quantity ofbitumen emulsion is determined as":

730 J SCII D RES VOL 65 SEPTEMBER 2006

intensity [millions of standard axles (msa)] projectedfor 5 and 10 years were found to be 3.8 msa and 9.3msa respectively. Hence required pavement crustthickness was found to be 700 mrn as against theexisting pavement thickness (410 mrn), In 1998,climatic conditions of NH-I A site near Patnitop were:temperature, -30DC to 40DC; maximum rainfall,1023 rnrn; and snowfall 384 111m.

High Rait(/(III Area: Iowai-Badarpur Road (NH - 44)Overall pavement crust thickness of Jowai-

Badarpur Road (NH-44) varies 255-390 mrn withblack top of 20-26 rnrn, 75-210 mrn of water-boundmacadam and 120-200 rnrn of stone soling. Theaverage crust thickness worked out to be 370 mrn.Study indicated CBR value of sub grade as 4%, andtraffic intensity was 1554 (CVPD). Projected trafficintensity was 9.9 msa and 24.1 msa after 5 years and10 years respectively. Overlay crust thickness workedout to be 200 mrn in terms of granular layer, whichwas to build up with 75 mm thick built-up spraygrout, 50 mrn thick bituminous macadam and 25 mrnthick dense bituminous concrete. The minimum andmaximum temperature of NH-44 site was 9DC and42DC with 3810 mm rainfall in 1997.

Desert Area: Hantunangurh-Sangeria RoadOverall pavement crust thickness consisted of

20 mrn premix carpet, 75 rnrn water bound macadam,120 rnm brick soling and 100 rnm kankar. Total crustthickness worked out to be 320 rnm. An equivalencyfactor of unity was assigned for existing black topsurfacing as it was in cracked and in fatigued state.Unsoaked CBR value of sub grade was 8%, and 3%when soaked for 4 days. Traffic was reported 600CVPD. The required granular thickness for Dcategory traffic (CI3R value, 8%) is 320 mmindicating that pavement was structurally adequate.Minimum and maximum temperature ofHanumangarh-Sangeria Road was 4.5DC and 49DCwith rainfall 126 mrn in 2001.

Materials and MethodsCold Mix Design of Semi Dense Bituminous Concrete (SnBC)Evaluation of Materials

CMD developed at CRRI involves optimization ofwater and bitumen emulsion for aggregates in themix. Aggregates are first moist with water to wet theaggregate surface and then coated with bitumenemulsion. Different sizes of aggregates are blended indifferent proportions to achieve the gradation of5DBC specification.

P = O.05A+O.IB+O.5C

where, P = Quantity of bitumen emulsion, % ; A =Percent aggregate retained on 2.8 rnrn sieve; B =Percent aggregate retained on 90 micron sieve and C= Percent aggregate passing on 90 micron sieve.

Optimum water for 5DBC was found 4110 byweight of aggregate. However, this quantity ofoptimum water content may vary depending on sitecondition and state of aggregates. The optimum watercontent for PMC was found 2% by weight ofaggregate.

Binder Optimisatiou using Marshall EquipmentCMD procedure utilizes standard Marshall

equipments in evaluation of mix properties':".Marshall test specimens in triplicate were preparedwith different binder content (bitumen emulsion).Different sizes of aggregates were blended to achievethe standard aggregate gradation of SDBC. Gradedaggregates (1100 g) were moistened with optimumwater uniformly. Bitumen emulsion (7%) were thenadded to the wet aggregates and mixed for 2 min foruniform binder coating. The cold mix was aerated ona sieve for 3 h. The cold mix was then transferred intothe Marshall mould with filter paper on base plate andcompacted with 50 blows of Marshall hammer onboth faces. Similarly, Marshall specimens wereprepared with optimum water content and other

PUNDHIR & NANDA: BITUMEN EMULSION BASED COLD MIX TECHNOLOGY FOR INDIAN ROADS 731

Table I-Sieve analysis and properties of aggregates from 35 BRTF Udhampur for SDBC

Sieve size % Passing Gradation of Specified

11.2 mrn 9.5 mrn down Stone dust blended aggregates gradation

A B C 40:40:20

22A mm 100 100 100 100 10013.2 mm 81 99 98 91 88-10011.2 mm 55 94 97 79 70-925.6 mrn 10 47 93 43 42-642.8mm 13 88 23 22-38710 p 1.6 58 12 11-24355 P 1.3 49 10 7-18180 ~I 0.8 32 7 5-1390 ~I 0.6 14 3 3-9Unit wt., kg 1m:; 1602 1650 1704

Table 2-Test results of cationic bitumen emulsion used in trials

S No. Properties of bitumen emulsion

SS0.01i)

i i)Residue on 600 micron IS sieve, % massViscosity by Sayholt Furol Viscometer, seconds. attemperature25°C50°CCoagulation of emulsion at low temperatureStorage stability after 24 h, %. maxParticle chargeStability to mixing with coarse aggregate, % coagulationCoating ability and water resistance(a) Coating. dry aggregatesCoating after spraying water(b) Coating. wet aggregatesCoating alter spraying waterStability to mixing cement, % coagulationMiscibility with water (coagulation)Test on residue:(a) Residue by-evaporation, %(b) Penetration. drnm at 25°C1I00 grn/S see(c) Ductility at 2711e. em(d) Solubility in trichloroethylene, %

MS

0.01

10lANil0.4+vc

GoodFairFairFairXNil

66.196100+99.0

Results

33.0

Nil0.1+ve

1.1

Nil

61.72058799.5

Requircment or IS: 8887-1995

MS SS

iii)iv)v)

vi)vii)

viii)ix )x)

0.05 mux. 0.05 max.

20-10050-400NilI

NilI

+vc<40

+vc<5

GoodFairFairFair

Nil<2Nil

57111in60-21075 min97.5 min

57 min60-21075 min.97.5 min

bitumen emulsion contents (8 and 9%). Marshallspecimens were extracted from the mould after 24 h.Specimens were then cured in air oven at 40°C for72 h. Marshall specimens were then subjected todifferent tests such as bulk density, stability and flowvalue. Marshall stability and flow values weredetermined in dry state at 25°C. Different propertiesof the mixes were determined and other designparameter like voids content, voids filled by binderwere calculated (Table 3).Bitumen emulsion (8%) was found optimum as

binder by wt of aggregate or 7.4% by wt of mix. Theproperties of cold mixes for test sections on NH-44and H-S Road were also determined and optimum

bitumen emulsion was found 8% by wt. of aggregateor 7.4% by weight of mix.

Mix Design of SDBC witlt BitU1Il1!1l

Mix design of SDBC with 801l00-grade bitumenwas undertaken following procedure given inAASHTO T-245 or ASTM: D-1559. The bulkdensity, stability and flow value at 60°C of Marshallspecimens were determined. The optimum bitumencontent for controlled (reference) sections was foundto be 5% by weight of aggregates of 4.76% by weightof mix.Marshall specimens were prepared with varying

bitumen contents of 4.5,5.0, 5.5 and 6%. Bitumen and

732 J SCI IND RES VOL 65 SEPTEMBER 2006

Table 3-Job mix formula or SDBC for test section on NH--I A with bitumen emulsion (SS)

S No. Properties Bitumen emulsion content

7.0% 8.0% 9.0%I Bitumen residue, % 4.2 48 5.42 Bulk density. glee 2.20 2.21 2.193 Volume or Aggregate, % 79.67 79.64 78.404 Volume or binder, % 8.87 9.95 11.235 Total 89.15 89.59 89.636 Voids, % 11.46 10.36 10.377 Voids in mineral aggregate (VMA), % 20.33 20.36 21.68 Voids filled with binder (VFB), % 43.63 48.87 21.69 Stability, kg at 25°C 790 900 60010 Flow, mill 7.5 7.0 6.5

aggregates were heated thoroughly at about 160°Cand 150°C respectively and mixed together untilaggregate particles were coated. The resulting mixturewas placed in Marshall mould and each sidecompacted with 50 blows of Marshall hammer as perprocedure given in AASHTO T-245 or ASTM: D-1559. Bulk density was determined at ambienttemperature. Stability and flow value of Marshallspecimens were determined at 60°C. Optimumbitumen content for controlled (reference) sectionswas found to be 5 % by weight of aggregates of4.76 % by weight of mix.

Construction of Test SectionsSpecifications Adoptedfor Test TrackPMC (20 mrn thick) with bitumen emulsion was

laid as per specification IRC: 97-1987 (presently IRC-14) while control section with normal bitumen of801100 grade was laid as per IRC: 14-1977. Laying of25 mm SDBC with bitumen was carried out as perIRC: 95-1987 and gradation of aggregates of samespecification was followed for construction of testsections with bitumen emulsion due to non-availability of construction specification of SDBCwith bitumen emulsion.

Laying of Test Sections with SDBCPreparation of Road Surface-The pavement

surface was thoroughly cleaned of all dirt, dust andother loose materials. All the cracks were cleaned andfilled with bitumen emulsion of medium setting (MS)grade by spraying the material @ 5 kg per 10 m2 area.Aggregates passing 2.8 mm and retained on 180 urnwere spread over the tacky surface and compactedwith 8-10 tons road roller for cracks of 3 mm wide.Other irregularity and pavement distress such aspothole and patch were repaired by cold mix preparedwith 11.2 mm down aggregate and bitumen emulsionMS grade. Cold mix in pothole or-patch was filled and

compacted when it turns black from brown. Repairwas completed at least a day before construction toallow curing of pavement surface to attain therequired stiffness. Proper cleaning was carried outbefore applying tack coat. In dry road condition,wetting (damping) of surface with water was alsorequired.

Preparation of Cold Mix-Construction ofbituminous road with bitumen emulsion requiressignificantly different procedures from those used forhot-mix hot laid construction. Drums of emulsionwere rolled to 5-6 m to and fro for twice or thrice tomake emulsion homogeneous before its use. Thegraded aggregates after blending different size ofaggregates were charged into concrete mixer drivenwith diesel engine. Optimum water content asdetermined in the laboratory was added .and mixed towet the aggregate surface. Required quantity ofbitumen emulsion of SS grade was then added intodamp aggregate at ambient temperature and mixed fortwo min to prepare cold mix. Additional time ofmixing was avoided as it causes decoating of binderfrom aggregates.

Application of Tack Coat-Tack coat with bitumenemulsion of MS or SS grade was applied @ 5.0 kg for10 m2 area by means of perforated cans as per IRCspecification. Holes of cans were cleaned with waterwhenever tack coating was discontinued to avoidchoking of the holes with residual bitumen. Cold mixwas spread when tack coat turned black from brownafter 15-20 min. At this point, all water of emulsionwas dissociated from bitumen by coagulation anddrained off leaving behind the residual bitumen on theroad surface, which was made wet or damp if founddry, before applying the tack coat with emulsion.

Transportation of Mix-Cold mix was thendischarged in wheel barrow and transported to the

PUNDHIR & NANDA : BITUMEN EMULSION BASED COLD MIX TECHNOLOGY FOR INDIAN ROADS 733

construction site for spreading cold mix on tacky roadsurface. Due care was exercised to avoid taking wheelbarrows on newly laid surface.

Spreading Cold Mix-In half of road width, coldmix was laid over tacky surface and spread uniformlyin required thickness (33 mm loose mix) by manualmethod. Cold mix turns black from brown after sometime when water of emulsion exudes after breaking ofemulsion. Cold mix was aerated for 2 h and thenrolled with 8-10 tons three-wheel roller to compactthe mix. Rolling was done with the outside drivewheel covering equal parts of the pavement andshoulder. Wheels were kept wet with water duringcompaction. Rolling was also repeated after 2 h.

Traffic Control= Traffic was regulated and testsection was left to open for traffic after 4-5 h. Trafficat some test sections could not be controlled aftercompletion of laying and hence, it was allowed atslow speed as per IRC guideline.

Laying Premix Carpet with EmulsionPreparation of Cold Mix-The blended aggregates

as per required grading were charged in the concretemixer and uniformly wet the aggregate with optimumquantity of premixing water. Emulsion of MS grade inrequired quantity was added into wet aggregategradually and mixed for 2 min to get uniform coating.Prolonged mixing was avoided, as it will decoat theaggregate.

Preparation of Road Surface-Pavement surfacewas cleaned of dirt, dust and loose materials. Tackcoat (5 kg/Iurrr') with SS grade emulsion wasprovided. When tack coat turned black from brown,cold mix was placed, spread and compacted asmentioned above to get premix carpet.

Seal Coat on Premix Carpet-Sand seal coatmaterial was prepared with aggregate passing2.36 mm and retained on 180 urn, Fine aggregate wastaken in the concrete mixer and then water (3%) wasadded to wet the aggregates uniformly. The emulsionof SS grade was poured gradually into the mixer andmixed for uniform coating. Decoating starts whenmixing time is increased in excess of about 2 min.This mix was spread over premix carpet andcompacted with 8-10 ton road roller to get thefinished surface on NH-IA and H-S Road. The liquidseal coat was provided on NH-44 by first tack coatingthe premix carpet with emulsion @12-13 kg per 10m2

area and then 6.3 mm passing aggregate was spreadover it. The aggregate layer was then compacted with

8-10 ton road roller. As per IRC: 97, liquid seal coatis only applicable in high rainfall area such as Assam.

Laying of Control SectionsThe control (reference) sections with specification

of 25 mm semi dense bituminous concrete withbitumen (IRC: 95-1987) and 20 mrn PMC withbitumen were also laid as controlled section as perIRC 14: 1977, using mini hot mix plant.

Problems and Remedial Measures During ConstructionThe problems encountered during laying of test

sections were as follows: i) Ball formation wasobserved when excessive dusty aggregate was usedfor preparation of cold mix. The excessive dust orclay must be removed through screening of aggregate;ii) Concrete mixer was suitable for PMC but notappropriate mixer for graded aggregates of SDBC.The binder and fine aggregate formed rich mix, whichsticks at the bottom of mixer. This further impairedthe mixing efficiency. The concrete mixer has to becleaned after 1 h mixing by tapping with woodenhammer; iii) Long setting time and tenderness ofgraded aggregate mix for longer period hinder inallowing the traffic immediately after construction.Normally traffic is allowed after 4-5 h, preferablyafter overnight curing; iv) Ball formation wasobserved when emulsion was mixed for sand sealpreparation for PMC; and v) These binder rich fineaggregate mix can be avoided if coarse aggregates arecharged into a concrete mixer and then coated withrequired quantity of emulsion. After initial coating,the finer aggregate fraction is added into coarseaggregate in between the mixing process.

Methodology for Performance Evaluation

Visual ObservationCRRJ and JOCL (R&D) Centre have devised a

proforma for performance evaluation (Table 4) withtypical performance data of 10th inspection of testsections on NH-IA. The performance evaluation ofroads with emulsion in rainy and desert climate hasbeen observed''".

Measurement of Cracked AreaCracked area in the test sections and control section

at all three-site locations was measured in wintermonths, as cracks are prominent in these months. Theroad section was divided into 25 m in segment anddistress in the form of cracking was measured andcalculated as the cracked area.

trichloroethylene were subjected for sieve analysis todetermine the aggregate gradations.

734 J SCI IND RES VOL 65 SEPTEMBER 2006

Table 4--Visual performance evaluation of test tack on NH-I A (Location: km.113.8 to 114.2; Date: 9.12. 1996; Inspection No.: 10'")

S No. Factor Performance Marks Test sections RemarkI 2 3 4

Bitumen i) Normal 10 8 8 8 T-Test Section with Emulsionii) Slightly dry/rich 7iii) Dry/rich 5iv) Very dry/rich 3

2 Aggregate I) Normal 10 8 8 8 6 R- Control SectionII) Less 5III)Excessive 3

3 Surface texture i) Good 10 8 7 7 6ii) Satisfactory 7iiijSrnooth 5iv) Coarse 3

4 Cracking i) No crack 10 7 6 7 2ii) Fine cracks 7iii) Localiscd cracks 5iv) Scattered cracks 3v) Extensive cracks 1

5 Potholes i) None 10 9 9 9 4ii) Very few 7iii) Scattered 5iv) Extensive 3

6 Surface evenness i) Good 10 8 7 6 6ii) Satisfactory 7iii) Poor 5iv) Very poor 3

7 Raveling i) None 10 7 7 7 5ii) Very few 7iii) Some 5iv) Extensive 3

8 Stripping i) None 10 8 9 8 5ii) Very few 7iii) Medium 5iv) High 3Total marks 63 61 60 40Max marks 80 80 80 80% marks 79 76 75 50

Grading: Good. > 80%; Satisfactory. 60-80%; Poor. 40-60%; and Bad. < 40%

Traffic DensityTraffic data of commercial vehicle using the test-

sections were periodically collected for 7 days as partof routine activities. The average traffic ofcommercial vehicles per day was calculated.

Testing of Bituminous MixesThe mix samples from test sections and control

sections were collected periodically after each one-year for thestudy for binder properties and change inaggregate gradation. The mix samples of test sectionsfrom different locations were taken out from the edgeof the road. The binder was recovered from the mixesby binder extractor, and finally by Abson's recoverymethod. The properties of binder were determined asper IS: 1201-1220. Aggregates left after washing with

Results and DiscussionPerformance of Test Section on NH IA (.1&K) in Snow BoundAreaPremix Carpet Specification

The construction of test sections was found good asindicated by the marks (93-95%) obtained for premixcarpet in first inspection carried out just afterconstruction. After 6 months, 2'11Iinspection indicatedthe deterioration of about 10% and 18% for PMC withemulsion and PMC with bitumen respectively.Evaluation of test and control section of PMC in 61h

inspection after 2'h. years showed the development ofdistress in control section with bitumen while test

PUNDHIR & ANDA: BITUMEN EMULSION BASED COLD MIX TECH 'OLOGY FOR INDIAN ROADS 735

a

c

b

Fig. l-e-Pcrformancc of PMC and SDBC on J-S Road ( H-I A): a) PMC with bitumen alter 2 '/2 yrs: b) PMC with emulsion after 5 yrs:c) SDBC with emulsion alter 5 yrs; d) SDBC with bitumen after 5 yrs on NH-I A

section with emulsion was having negligible distress.Performance of PMC with emulsion was satisfactorywhile PMC with bitumen (Fig. la) was poor after2'/2 years service life. The distress was alsomanifested by allotted marks for test section (74%)and reference section (56%) in 7th inspection after 3years service life. The evaluation of PMC in 11thinspection after 51

/2 years showed the betterperformance of PMC (76% marks) with emulsion(Fig. I b) than PMC with bitumen (42% marks).

Performance of PMC with emulsion and controlsection with bitumen is plotted against the pavement

service life, which also shows the better performanceof PMC with emulsion in comparison of PMC withbitumen (Fig. 2a). The analysis with limiting value 50percent shows the service life of 6 years for PMCwith emulsion and 4 years for PMC with bitumen.Semi-Dense Bituminous COilcrete Specification

The construction of test and control section wasgood (97% marks) in I" inspection conducted justafter construction. The post monsoon inspection after6 months indicated deterioration in test section (8%)and control section (10%). The half road widthof SDBC with emulsion at descending gradient was

736 J SCIIND RES VOL 65 SEPTEMBER 2006

100eft. 90" 80Q) 70g 60C\l 50E 40o 30't: 20Q) 10a.. 0

o

[~

...•.......•...•.

--.....:<,R -+- (Emulsion) I-......

-(Bitumen)

a

6234 5Service life, Years

7

10090

ai 80g 70C\l 60Eo 50't: 40Q)o, 30

20o

b

~--,...

--........•.••.~-+-(EmUISiOn) I ""'A

___ (Bitumen)

Fig. 2-Pcrrormancc 01" PMC and SDBC with service life in years on J-S Road (NH-I A): a) PMC with emulsion and bitumen; b) SDBCwith emulsion and bitumen: c) Pavement distress in PMC with emulsion and bitumen: d) Pavement distress in SDBC with emulsion andbitumen

eft.

c80

m 70 7 1~ 60 -+-PMC(Bitumen)~ 50 _PMC (Emulsion) /Q)4Q .•-6/ ...~30 ./

o 20 _ .,/eft. 10 £ .-..:--

o "o , 2 3 4

Service life, Years5

234 5Service life, Years

6 7

5

d30

•If'J -+-SDBC (Bitumen) I II___ SDBC (Emulsion)

II

"-"'"-

C\lQ) 25

~ 20"0Q)-6 15C\lo 10

eft. 5

oo 234

Service life, Years

PUNDHIR & NANDA : BITUMEN EMULSION BASED COLD MIX TECHNOLOGY FOR INDIAN ROADS 737

affected by the formation of humps as a result ofdevelopment of high sheer forces due to breakingaction of vehicles. The other road half width remainedunaffected. Development of distress in form of humpswas prominent at initial curing period of cold mixwhere cold mix remained tender due to the presenceof petroleum distillate in binder incorporated duringmanufacturing of emulsion. The higher percentage offine aggregate fractions in the mix also resulted inshoving and hump formation in the test section. Theperformance of SOBC with emulsion (75%) andSOBC with bitumen (76%) was comparable after3 years. The performance of SOBC with emulsion(Fig. lc, 55% marks) and SOBC with bitumen (Fig.l d, 65% marks) after 5 years was also foundcomparable. The graphs between performance vIspavement service life in years show comparable lifeof test section and control section (Fig. 2b).

Pavement DistressCracked area (4.4%) in PMC with emulsion was

quite less than cracked area (3.4%) in PMC withbitumen after 2.5-year service life. Distress in theform of cracks further aggravated to higher degreewith passages of time in control section of PMC withbitumen while in test section of PMC with emulsionremained less affected. This may be attributed due tothe low viscosity of emulsion, which penetrated in thecracks to the greater depth and thus helped in sealingthem to retard the reflection of cracks to overlay.Graphs between cracked area vIs service life in years(Figs 2 c & d) show better performance of PMC andSOBC with emulsion than PMC and SOBC withbitumen.

Performance of Test Sections on NIl 44 (Assam) in HighRainfall AreaPremix Carpet Specification

Construction of test section was good (97% marks).Post monsoon inspection after 6 months showeddeterioration in PMC with emulsion (11%) andcontrol section with bitumen (18%). This indicatedthe faster deterioration in control section withbitumen. The performance evaluation of test sectionafter one year showed better performance of PMCwith emulsion (90% marks) than PMC with bitumen(87% marks). After three years, performance of PMCwith emulsion (73.3% marks) was found good incomparison with PMC with bitumen (66.6% marks).Performance of PMC with emulsion (79%)wasagain found better than PMC with bitumen (74%)

after 4 years service life. Performance evaluation after5 years service life indicated better performance ofPMC with emulsion (Fig. 3a, 74% marks) than PMCwith bitumen (Fig. 3b, 66% marks).

The binder at maximum wheel path worked up toreach the surface and the rich binder appearance wasobserved. The binder works faster to reach at the topof road surface when it is used in the form ofemulsion due to the presence of kerosene in thebinder, which has been added at the time ofmanufacturing process of emulsion. Though thisphenomenon was prevalent in this region, the higherdegree of richness was found in test section of PMCwith emulsion.

Visual observation and other factors indicated theservice life of PMC with emulsion of about 6 years ascomparative to 5 years for PMC with bitumen. Thegraph between performance vIs service life indicatedbetter performance of PMC with emulsion than PMCwith bitumen (Fig. 4a)

Semi Delise Biuuninous Concrete Test SectionFirst inspection of test section showed good

construction. The 2"d inspection after 6 monthsshowed a deterioration level for test section SDBC(12%) with emulsion and controlled section SDBC(17%) with bitumen. Unevenness in SDBC withemulsion was observed after 6 months on half widthof road at the descending gradient where high shearforces develop due to braking action of vehicles.Humps were propagated with passage of time atdescending gradient due to tenderness of cold mixduring initial curing time. Development of cracks wasprominent in the control section SDBC with bitumenafter 2 years service life. The distress due to crackingwas very less in test section SDBC with emulsionafter 2 years service life. The performance of SDBCwith emulsion (Fig. 3c, 73 % marks) was slightlybetter than SDBC with bitumen (Fig. 3d, 71 % marks)after 5 years service life. The graph betweenperformance vs service life of pavement NH-44(Fig. 4b) indicated better performance of SDBC withemulsion than SDBC with bitumen.

Pavement DistressDevelopment of cracks in PMC with bitumen was

prominent while PMC with emulsion was lessaffected with cracks; indicating that emulsion retardspropagation of cracks. Cracked area was higher incontrol sections with bitumen than in test section withemulsion (Figs 4 c & d).

b

738 J SCI IND RES VOL 65 SEPTEMBER 2006

a

c d

Fig. 3-Performance or PMC and SDBC on J-B Road (NH-44): a) PMC with emulsion after 5 yrs; b) PMC with bitumen after 5 yrs; c)SDBC with bitumen after 3 yrs; d) SDBC with emulsion after 3 yrs

Performance of Test Sections on I1-S Road (Rajasthan) inDesertPremix Carpet SpecificationConstruction of test section and control sections

was found good in the first inspection just afterconstructions. Post monsoon inspection indicateddeterioration of negligible magnitude due to lowrainfall. Performance evaluation after 2 years showedbetter performance of PMC with emulsion (Fig. Sa,87 % marks) than PMC with bitumen (83% marks).After 2 1/2 years, the performance of PMC withemulsion (53%) was found to be slightly less thanPMC with bitumen (66%). Reduced performance of

PMC with emulsion may be due to the use of sandseal coat, which is problematic with ball formationduring mixing sand with emulsion. Visual observationindicated presence of higher binder content. Graphbetween pavement performance vis pavement servicelife (Fig. 6a) shows comparable service life of testsections with emulsion and control section withbitumen.

Semi-Dense Bituminous COilcreteConstruction of test section SDBC with emulsion

and control section SDBC 'with bitumen was ratedgood after obtaining about 91 % marks. Performance

- --~ -------

PUNDHIR & I A DA: BITUME EMULSIO BASED COLD MIX TECHNOLOGY FOR I DIAN ROADS 739

a1009080

B 70c:~ 60~ 50G)Il. 40

3020

o

r- t<,~. !

~~~ ~-:~"IIo ~ (Emulsion)

! (Bitumen) \

2 3Service Life, Years

4 5

b1009080;f!

oj 70uc:('II 60E•...g 50G)Il. 40 ~ (Emulsion)

30 -II- (Bitumen)

200 2 3 4 5

Service Life, Years

d---1

IC

50 -~SDBC (Emulsion)

1540 -ll-SDBC (Bitumen)

('II

--+-PMC (Bitumen) G)•..co __ PMC (Emulsion) octe "0 30<I: .. 10 G)-e -"u'" I!! 20..•u o~o 5 . :::e

0 10*'0

0 00 Se~ce Life, YJlars 4 5 Service Life, Years

Fig. 4--Pcrrormancc or PMC and SDBC with service life in years on J-B Road (NH-44): a) PMC with emulsion and bitumen; b) SDBCwith emulsion and bitumen: c) Pavement distress in PMC with emulsion and bitumen; d) Pavement distress in SDBC with emulsion andhirurncn

740

b

J SCIINO RES VOL 6S SEPTEMBER 2006

a

c

Fig. S-Peri"ormanee or PMC and SOBC on H-S Road (SH-4S): a) PMC with emulsion alter ilz yrs; b) SOBC with emulsion alter 2 1/2

yrs. e) SOBC with bitumen alter S years

evaluation of section with emulsion (88%) showedcomparable service life of SDBC with bitumen (85%)after 2 years. Distress in the form of cracking wasfound less in SDBC with emulsion (87%) incomparison to SDBC with bitumen (83%).Performance evaluation in u" inspection after 5years service life showed that performance of SDBCwith emulsion (Fig. 5b, 67% marks) was less incomparison with SDBC with bitumen (Fig. 5c, 72%marks). The graph between pavement performance vspavement service life (Fig. 6b) shows thatperformance of SDBC with emulsion and control

section of SDBC with bitumen was comparable withpavement service life of about 5 years.Pavement Distress

Percent cracked area in PMC with emulsion was lessin comparison to PMC with bitumen at initial stages ofpavement service life of 1'/-2 years and afterward thetrend reversed (Fig. 6c). This may be due to the sandseal coat provided on PMC, which was problematicdue to the ball formation at the time of mixingemulsion in sand. The cracked area with passage oftime in SDBC with emulsion was found less 111

comparison with SDBC with bitumen (Fig. 6d).

PU DHIR & NANDA : BITUME EMULSIO BASED COLD MIX TECH OLOGY FOR I DIAN ROADS 741

ah.

~ ....., --- ..•..

~-+- (Emulsion) ~~

--- (Bitumen) I ~

100

90

c; 80c~ 70.g 60:.

50

40o 2 3

Service Life, years5

IV 12f 10~ 8~ 6~ 4..o 2

o

b

.A

I -+-PMC (Emulsion) I / .....•-tl-PMC (Bitumen) »:>

-~.- :..¥

o 21 3 4Service Life, years

~12~--------------------~~10~~.~~~(~~~~-)~~--~~~o 8 _~(BturB1)~ 6 'J======A?---1o 4+----- __~~~--------~~ 2·,1---...-=:::::!.----!o~ O+---~----~--~----~--~

o

i1]200:: -+-sac (BtlJTen)« 15 _S!H;{8rUsioo)Cl~ 10o« 50::

5 o0~00 1 2 3 4 5

SERVICE UFE IN YEARS

c

1 2 3 4

SERJlCE UFE IN YEARS

4

Fig, 6--Performance of PMC and SDBC with service life in years on H-S Road (SH-4S): a) PMC with emulsion and bitumen; b) SDBCwith emulsion and bitumen; c) Pavement distress in PMC with emulsion and bitumen; d) Pavement distress in SDBC with emulsion andbitumen

5

d

development of reflective cracks on the overlays.Quantity of bitumen emulsion provided for PMC inthe tentati ve specification IRC: 97-1987 is observedtowards higher side. Finer aggregate gradation forSDBC using emulsion has a longer setting time,which leads to deformation at higher load stresses atroad gradient leading to shoving and slippage of mix.Excess of fine fraction of aggregates in SDBC tendsto develop ball-forming resulting in rich binder spotson bituminous surfacing after compaction. Theaggregates with dust and clay are not suitable, as ballformation is observed during mixing with emulsion.Construction of bituminous roads and maintenance ispossible with bitumen emulsion in bad weather, rainyseason and at lower ambient temperature (7°C).Service life of bituminous pavement with bitumenemulsion is quite comparable or even better thanthose paved using bitumen.

742 J SCI IND RES VOL 65 SEPTEMBER 2006

Table 5---Comparative cost of bituminous surfacing withemulsion and bitumen

S No. Specification Thickness, mm Binder Cost/rrr', Rs

I234

SDBCSDBCPMCPMC

47494340

25252020

BitumenEmulsionBitumenEmulsion

Hardening of BinderThe mix samples from test sections were collected

periodically after every year for the study for bindercharacterization and change in aggregate gradation.The samples of mix from road were taken out fromnear edge of the road. The binder was recovered fromthe mixes by binder extractor and finally by Abson'srecovery method for sections at differentlocations and was characterized. Hardening of binderin test section with emulsion was found to be less incomparison with control sections where hardeningwas prominent. The change in gradations of aggregatefor SDBC was found higher in control section than intest section with emulsion. This may be due to theaggregate benefication in properties by the ingress ofemulsion in aggregate core".

Cost Analysis of Construction with Emulsion and BitumenPrimary energy saving in using emulsion is

elimination of the fuel required to heat and dry theaggregate to provide good coating and workability ofbituminous mix. Higher cost of emulsion was offsetby the elimination of heating of binder and aggregatefor preparation of mix and tack coating the existingarea. Cost economics of road construction (7 m wide,100 m long) with total area 700 m2 PMC and SDBCwith bitumen 801100 and bitumen emulsion has beencalculated. Construction cost of PMC per sq m areahas been found Rs 43 for bitumen and Rs 40 foremulsion (Table 5). Moreover, the life of PMC withemulsion was found to be 6 years than PMC withbitumen was found 10 be 4 years on NH-1A nearPatnitop (J&K). Similar trend of pavementperformance has been observed with test section onJowai-Badarpur Road (NH-44) near Silchar.

ConclusionsPremix carpet with emulsion provides better

performance than with bitumen. Liquid seal coat onpremix carpet with emulsion provides betterperformance while sand seal coat is problematic asmixing emulsion with sand leads to ball formation.The use of bitumen emulsion as tack coat retards

AcknowledgementsAuthors thank Dr Sunil Bose of CRRl and Mr B R

Tyagi and Mr M P Kala of lOC, for valuablesuggestions. Authors also thank Director General,Border Roads Organisation, Commanding Officers of35 BRTF, 36 BRTF and 49 BRTF, and OCs ofdifferent RCC for their invaluable help andsuggestions during construction and monitoring oftest sections.

ReferencesI Pundhir N K S, Arya I R. Tyagi B R & Kala M P. Field trials

on cationic hitumen emulsion on National Highway. Res 8111/No. 61 (Indian Road Congress. Jam Nagar House. NewDelhi) December 1999.

2 Arya I R & Pundhir N K S. Emulsified cold mixes-design,construction and field performance. IRC indian Highway Vol29, No.3 (Indian Road Congress. Jam Nagar House. NewDelhi) March 200 I.

3 Arya I R & Pundhir N K S, Bitumen emulsion as efficientbinder for construction and maintenance of hill roads, IRe'Sell/ill 011 Design, Construction of Hill Road (Indian RoadCongress. Jam Nagar House, New Delhi) J 9-20 June 1995.

4 Bituminous emulsion for highway pavement. Synthesis ofHighway Practice Rep No. 30. (TRB-NRC, Washington DC) 1975.8-12.

5 Hicks R G. Santucci. Fink D G & Williamson R.Performance evaluation of open-graded ctnulsified asphaltpavement (AAPT. Sl Louis. M O. USA) 1983.441.

6 A basic asphalt emulsion. /vsphalt Institute Manual (MS-19).36-48.

7 Pundhir N K S, Arya I R. Tyagi B R & Kala M P. Field trialson cationic bitumen emulsion in desert climate. IRe 111I

Semin New Trends ill Highway Construction (Indian RoadCongress, Jam Nagar House. New Delhi) 13-14 Nov 1998.

8 Pundhir N K S, Design and Construction of Road with

PUNDHIR & NANDA : BITUMEN EMULSION BASED COLD MIX TECHNOLOGY FOR INDIAN ROADS 743

Bitumen Emulsion (J Civil Eng. & Construction, CRRI, NewDelhi) November 200 I.

9 Pundhir N K S & Bose S, Use of cold mix technology for

road construction in cold climate, IRC 1111 Semin HighwayRehabilitation & Maintenance (Indian Road Congress. JamNagar House, New Delhi) 12-13 November 1999.