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19Indian Highways, September 2016

1. Introduction

1.1 General

One potential area of usagefor locally availablematerial in flexible

pavement construction is in the unboundlayers of the pavements such as base, subbase that rest on compacted soil layercalled the sub-grade. The performance ofunbound granular pavementlayers dependsgreatly on the properties and quality of theaggregates used. One of the factorscontributingto failure inboth rigid andflexible pavements is the poorperformance of unbound layersresulting inreduced life andcostly maintenance. Thecharacteristics of unboundlayers dependon shear strength,density, gradation, finescontent, moisture level, particle

Use of Locally Available NonConventional Materials in the

Construction of Rural Road Pavementsby Dr. Suresh Kumar, Er. Nazish Akhtar

Abstract

The paper suggests a framework for preparing a database on the availability of materials in a locality with alldetails such as quantity available, engineering properties and how they can be used in pavement construction.

The paper is aimed at providing suitable gradation for sub base layer in flexible pavement with locally available

materials known as marginal material. Preliminary study was carried out to identify locally available constructionmaterials. For this purpose different types of local materials were tried to explore their potential of using in sub-

base layers as well as in improving sub-grade strength.

Based on theexperimental studies carried out on the construction materials such as moorum, kankar,gravel, construction and demolition waste collected from different areas of Koderma town and in the vicinity of

Chandwara block, in koderma district of Jharkhand State, it has been observed that the selected materials

which are abundantly available in the area could be used effectively for the construction of unbound layers ofpavement for moderate traffic road.

The materials experimented include marginal materials such as construction and demolition waste (DismantledP.C.C etc.), Gravel &kankar, soil/moorum (all locally available). Exhaustive tests were performed in grading different

components & the CBR value of all the mixes were measured, along with other strength parameters and

properties. Field compaction tests by sand replacement method (as prescribed by National Rural Road DevelopmentAgency, New Delhi) were carried out to achieve optimum conditions at proctor density.

Based on the test result of designed mix the design of pavement as per IRC codal provisions were done. Itis noteworthy, that the pavement designed based on use of non-conventional materials in GSB layer and sub-

grade strength improvement (CBR increasing from 4.43 to 6.03 for sub-grade) result in the reduction of overall

pavement thickness by 50 mm, resulting in the considerable saving in materials and overall cost as well aspreserving our precious environment.

Key Words:-

CBR–California bearing ratio, GSB–Granular Sub-base, IRC–Indian Road Congress, PCC–Plain Cement Concrete

angularity and surface texture,degradation during construction andunder repeated loads, freeze-thawcycles and drain-ability.

Thus the selection of material forconstruction of unbound granular layersplays a prominent role in the pavementconstruction and its performance.However, the quality of locally availableaggregate or borrowed aggregate can bemodified by using the stabilizationtechnique, which results in lesserthickness of unbound layer and betterpavement performance. The material usedfor construction of unbound granularlayers is many a time borrowed fromother places thereby increasing the costof pavement construction. In the presentwork, the mixture of marginal materials

locally available and the local soil wasprepared in an engineered way so that thecharacteristics of sub-base layer thusprepared meets the specificationprescribed in cl. 5.2.2.3, Table-3, sl. no. 3of IRC SP-72, 2007. The PI value obtainedfor the graded mix of sub-base was 3.5(less than 6 as prescribed in IRC SP-72,2007). The resulting design-mix having P.I.value 3.5 & C.B.R value 26.5 (named astrial mix b) meets the requirementmentioned in cl. 7.1.1., p-20-22 of IRCSP-72, 2007.

Presently the existing designmethods for bituminous pavements oftrunk roads are being revised toincorporate stabilization techniques andbound materials. However more costeffective approach is needed for low

20 Indian Highways, September 2016

volume roads to bring down theirconstruction cost. In this regard,research work done abroad hasbrought into light increasingamount of evidenceto show thatmoreuse can be made of locallyavailable materials forconstruction of lowtraffic

Volume rural roads. Lowvolume roads typically carry lessthan 200 vehicles per day. Overa 20 year period, even with highgrowth rates, it is unlikely that thedesign traffic loading will exceed onemillion cumulative equivalent standardaxles (msa). A very wide variety of non-conventional materials have beensuccessfully used where traffic is low.

The sub-base course acts assecondary load spreading layer in flexiblepavement and also as a drainage layer.To ensure drainage function efficiently,the amount of fines (material passing0.075 mm sieve) must be limited. Forwell-sealed roads in tropical areas, andwhere surface and road side drains aregood, unsaturated moisture conditionsprevail and sub-base specifications maybe relaxed. The selection of sub-basematerial will therefore depend on thedesign function of the layer and theanticipated moisture regime, both in-service and during construction. In manycircumstances the requirements of a sub-base are governed by its ability to supportconstruction traffic without excessivedeformation or raveling. A high qualitysub-base material is therefore requiredwhere loading or climatic conditions aresevere. Otherwise, in case of low trafficvolume roads,the material requirementsfor sub-base course can be relaxed.

The road base is the main loadspreading layer of the pavement. A widerange of materials can beused inunbound layers of road includingconstruction and demolition waste,kankar, moorum, gravels, etc. Thesuitability of materials for use dependsprimarily on thedesign traffic level andthe local environment.

Road bases are expected to conformto specified material gradation andprovide high mechanical stability. Thegrading should contain sufficient lowplasticity fines (material passing 425micron sieve) to produce dense material,with less than 5 per cent air voids whencompacted.

In the present work, differentmaterials such as construction &demolition waste, gravel, kankar,moorum/soil (all locally available) etc.have been tried. The test result pertainingto the use of marginal materials werefound to be encouraging in accordancewith the IRC codal provisions, the samehave been used for actual implementa-tion under pilot plant construction.

The present research is wellsupported by the directions issued by IRCwhich is as below.

The Indian Road Congress (IRC)/NRRDA guidelines advocate use oflocally available materials. IRC SP:72,

2007, states that by making theuse of locally available materials,suitable and economical designscan be worked out.

1.2 Scope

Scope of the work includesstudy of possibility of usingmarginal materials which arelocally available as sub-basematerials in flexible pavementand as a stabilizing agent for sub-grade strength improve-ment.

1.3 Objectives

The specific objectives of thepresent study are:

1. To investigate the possibility of usingmarginal material in sub-base of flexiblepavement.

2. To determine CBR value & otherproperties of mixture of soil and marginalmaterial in different proportions, atproctor density.

3. To improve sub-grade strength in ordertoreduce the design pavement thickness.

4. To design the pavement based on theresults of investigation.

5. To implement the designed data inactual road construction on a pilot plantscale.

2. Use of Marginal Materialin Sub-base

2.1 Materials

The physical property of marginalmaterial selected and used are given intable-1.

Dr. SURESH KUMARLM-35329

Associate ProfessorMIT Muzaffarpur-842003

sureshmit_civil@yahoo.co.in

Er. NAZISH AKHTARLM-100030

M.Tech Student,Bihar-842003

nazish1989akhtar@gmail.com

Table No.-1 Physical Property of Marginal Material

PI: Plasticity Index; MDD: Maximum dry density; OMC: Optimum Moisture Content.

Sl. No. Test Trial MixA B C D E F

1 Soaked 23 26.5 18.01 13.5 13.2 12.91CBR (%)

2 PI Value 5.5 3.5 7 7.5 8 103 Water 3 3 3.5 3.5 3.5 3.5

Absorption4 MDD gm/cc 2 2.15 1.99 1.99 1.89 1.895 OMC 8.97 8.66 9.42 9.22 9.10 9.11

21Indian Highways, September 2016

2.2 Gradation

In order to obtain the gradation ofmarginal materials, six mix proportionswere prepared. Sieve analysis werecarried out and the average values ofresults were rounded off, and used forthe gradation to be followed during theinvestigation. Table 2 shows thegradation obtained.

The respective proportions in trialmixes are as described under

Trial Mix (A)- 40% soil/moorum,25% kankar, 15% gravel, 20%construction and demolitionwaste.

Trial Mix (B)- 30% soil/moorum,25% kankar, 25% gravel, 20%construction and demolition waste.

Trial Mix (C)- 40% soil/moorum,20% kankar, 15% gravel, 25%construction and demolition waste.

Trial Mix (D)- 45% soil/moorum,25% kankar, 10% gravel, 20%

construction and demolition waste.

Trial Mix (E)- 50% soil/moorum,20% kankar, 10% gravel, 20%construction and demolition waste.

Trial Mix (F)- 55% soil/moorum,20% kankar, 7% gravel, 18%construction and demolition waste.

From the data presented in tableno.2, it is evident that the gradationobtained in case of trial mix B is mostsuitable. Therefore further investigationsare carried out on this selected mix (trialmix B).

The salient features of the selectedmix is given below:

From the data presented in table no.2, it is evident that the gradutionrequirements in case of trial mix B ismost suitable. Therefore furtherinvestigations are carried out on thisselected mix (trial mix B).

The salient features of the selectedmix is given below:

2.3 CBR

Standard proctor test was carriedout for various proportions of marginalmaterial. The test samples wereprepared by static compaction. Afterobtaining the maximum dry density fromthe proctor test, CBR test was carriedout at that density.

The salient features of the selectedmix is given below :

Penetration (mm)

Table No. -4 Soaked CBR and Modified Proctor density

1 Soaked CBR (%) 26.52 MDD gm/cc 2.153 OMC 8.66

Table No. -2 Gradation of Marginal Material

Sl. No. Sieve Trial MixSize A B C D E F

1 45 mm 100 100 100 100 100 1002 26.5 mm 75-95 N-A 100 100 100 1003 9.5mm 40-75 30.60 50-85 60-100 100 1004 4.75mm 30-60 25-55 35-65 50-85 55-100 70-1005 2mm 20-45 15-40 25-50 40-70 40-100 55-1006 425 micron 15-30 8-20 15-30 25-45 20-50 30-707 75 micron 5-20 2-8 5-15 5-20 6-20 8-25

Table No. -3 Sieve Analysis

IS (mm) % of Passing Lower Limit of Passing Uper Limit of Passing45.00 100 100 1009.500 51.37 30 604.750 32.43 25 552.000 19.56 15 400.425 12.47 8 200.075 3.77 2 8

Graph No.-1 Graph no. 2

22 Indian Highways, September 2016

Table no.-7 The selection of mixproperty for sub-grade material

Graph no. 3

Graph no. 4

Graph no. 5

3. Construction Methodo-logy

3.1 Sub grade stabilization

Stabilization of existing sub-gradewas done with the use of marginalmaterials in different proportion mixedwith ordinary soil.

For this purpose 10% marginalmaterial & 90% ordinary soil was used.The salient properties of marginalmaterial & ordinary soil are describedin table no. 5,6 & 7

The physical property of ordinarysoil used, are given in table no. 5

Sl. Type of OMC MDD SoakedNo. Material CBR1 Soil 16 1.82 4.432 Marginal 8.66 2.15 26.5

Materialgrade (B)

3 Soil/ 13 1.91 6.03moorum+

10%Marginalmaterial

Based on the results on soilstabilization by marginal materials (tableno. 6) the final selection of soil: Marginalmaterial mix composition workout to be90%: 10%.

The relevant properties are asunder:

The salient features of ordinary soilis given below:

The salient features of thestabilized mix of soil and marginalmaterial is given below:

SUB-GRADE CONSTRUC-TION- Immediately prior to the layingof sub-grade the ground were finishedto MORTH Clause 301 or 305 asapplicable. The ground was prepared byremoving all vegetation and otherextraneous matter, lightly sprinkled withwater and rolled with two passes of 80-100 kN smooth wheeled roller.

The 10% marginal material and90% local soil were properly mixed andplaced on the rolled surface in threelayers. The first layer of 100 mmthickness, 2nd layer of 100 mm thicknessand the third layer of 50 mm thicknesswas placed, every time watered androlled with a 80-100 kN smooth wheeledroller. Thus, the stabilized layer of sub-grade showed increase of CBR valuefrom 4.43 to 6.03. The compaction testresults are as mentioned below:

3.2 Sub-Base preparation

The sub-base layer was preparedwith the use of marginal material suchas construction & demolition waste(dismantled PCC etc.) Gravel, Kankar,moorum (All locally available) in thedesigned proportion (trial mix B)

The salient properties of sub-basematerials such as Gradation, CBR value,OMC & MDD and compaction testsare presented in table no. 2,3,4,9 &graphno. 1,2 respectively.

SUB-BASE CONSTRUCTION:The designed thickness of sub-baselayer worked out to be 125 mm. as perthe pavement design.Therefore the

Table No.5 Physical property ofordinary Soil

Table No. 6 –Marginal material mixed withordinary soil in different proportions.

Sl. No. Properties Value1 Liquid Limit 412 Plastic Limit 243 Plasticity Index 174 OMC 165 MDD 1.826 Soaked CBR (%) 4.43

Sl. Type of OMCMDD SoakedNo. Material CBR

1 Soil 16 1.82 4.432 Marginal 8.66 2.15 26.5

Materialgrade B

3 Soil+ 5% 14 1.89 5.70Marginalmaterial

4 Soil+ 10% 13 1.91 6.03Marginalmaterial

Graph no. 6

23Indian Highways, September 2016

Table No. 8

Field Density of Sub-Grade(Sand replacement method)

Observation Tables

TableNo. 9

Field Density of GSB Non-Conventional Material(N.C.M.) (Sand replacement method)

Observation Tables Thickness of layer in mm = 125

entire layer was laid in single stroke asper the standard procedure laid down byIRC codes. The compaction test resultsare as mentioned below.

4. Pavement Design

The design of flexible pavementinvolves the interplay of severalvariables, such as, The Wheel loads,Traffic, Climate, Terrain, Soilcharacteristics and sub-grade conditions.With a view to have a unified approach

for working out the design of flexiblepavement in the country, the IRCguidelines in IRC SP-72-2007 is widelyfollowed. The two most important factorsfor pavement design are the CBR valuesof the soil and the traffic census data.CBR value for designed graded materialof sub-base can be referred from tableno. 4 Graph no. 1,2. The traffic censusdata was collected from the roads invicinity of the proposed site.

(a) Calibration of Sand(i) Mean weight of sand in cone

(of pouring cylinder) (W2) in gm = 360

(ii) Volume of calibrating cylinder (V)in cc.= 1180

(iii) Weight of sand (+cylinder) beforepouring (W

1) in gm. = 6105

(iv) Mean weight of sand (+cylinder)after pouring (W

3) in gm. = 4067

(v) Weight of sand to fill calibratingcylinder. (Wa=W

1-W

2-W

3) in gm.= 1678

(vi) Bulk density of sand Ys = (W

a/V)

gm/cc = 1.4220(b) Determination of Soil Density

(i) Determination number =(ii) Weight of wet Soil from hole

“Ww” gm = 2113(iii) Weight of sand (+cylinder) before

pouring “W1” in gm. = 5627

(iv) Weight of sand (+cylinder) afterpouring “W

4” in gm. = 3875

(v) Weight of sand in hole, in gm.“W

b” = (W

1-W

4-W

2) = 1392

(vi) Wet density of Soil “Yw”=W

w/V

h2.153

(vii) Moisture content Container No.=(viii) Moisture content (%) = “w”= 13.000(ix) Wt of dry soil from hole = 1838(x) Dry density “Y

d” = Y

w* 100/

(100+w) gm/cc = 1.905(xi) MDD = 1.910(xii) % Compaction = Y

d/MDD*100 99.738

(a) Calibration of Sand(i) Mean weight of sand in cone

(of pouring cylinder) (W2) in gm = 361

(ii) Volume of calibrating cylinder (V)in cc.= 1180

(iii) Weight of sand (+cylinder) beforepouring (W

1) in gm. = 5845

(iv) Mean weight of sand (+cylinder)after pouring (W

3) in gm. = 3802

(v) Weight of sand to fill calibratingcylinder. (Wa=W

1-W

2-W

3) in gm. = 1682

(vi) Bulk density of sand Ys = (W

a/V)

gm/cc = 1.4250(b) Determination of GSB Density (N.C.M)

(i) Determination number =(ii) Weight of wet GSB from hole

“Ww” gm 2296(iii) Weight of sand (+cylinder) before

pouring “W1” in gm. = 5145

(iv) Weight of sand (+cylinder) afterpouring “W

4” in gm. = 3389

(v) Weight of sand in hole, in gm.“W

b” = (W

1-W

4-W

2) = 1395

(vi) Wet density of GSB “Yw”=W

w/V

h2.339

(vii) Moisture content Container No.=(viii) Moisture content (%) = “w”= 8.660(ix) Wt of dry GSB from hole = 2097(x) Dry density “Y

d” = Y

w* 100 /

(100+w) gm/cc = 2.152(xi) MDD = 2.150(xii) % Compaction = Y

d/MDD*100 100.093

Design calculation (As per IRC SP-72-2007)

The detailed design is as follows.

24 Indian Highways, September 2016

DESIGN OF FLEXIBLEPAVEMENT

(IRC:SP:72-2007)

CBR – 6.00%

Sub grade category – S3

Design type : Stabilized sub-gradewith non-conventional material ingranular sub-base.

There are 2 harvesting season inthe area, each having a duration of about65 days, The above traffic count datawas collected 4 years before openingthe road to traffic. Since the peakharvesting season traffic data is notavailable, traffic volume has beenconsidered double the traffic during thenon-harvesting season (n=1).

Computation of Design TrafficParameter

Total motorized & Non motorizedvehicle per day (as per traffic surveyconducted and forecasting according tospecification of IRC: SP:72-2007 & IRC: SP: 108).

Bicycle & Cycle Rickshaw = 180

Motor Cycle = 50

Cars, Jeeps & LCV = 7

Full sized trucks/bus (Laden) = 1

Full sized trucks/bus (Un-Laden) = 1

Agricultural Tractor-Trailers and

Jugads (L) = 9

Agriculture Tractor-Trailers and

Jugads (UL) = 10

Animal-Drawn carts (Solid Wheeled) = 4

Total = 262

Average Annual Daily = T+1.2nTt/365

= 262+(1.2x1x262x65)/365

AADT = 318

Where, T = Average Traffic, plying perday during the lean season = 262

(Assumed as per IRC:58-2002)

n = Design life in years = 10

Cumulative ESAL = 60000-100000= T3

(Sec. 3.5)

application

Pavement Thickness andComposition

For cumulative ESAL applicationsof 61100, referring to the Trafficcategory in the range 60000-100000 andthe sub-grade category of CBR, 5-6, asper Fig 4 of Page no. 16, 275mm thickpavement should be provided.

Design pavement crust thickness

(In mm) = 275 mm

Existing crust thickness

(measured) In mm (Avg.) = 0 mm

A Recommended For new CrustLayers:

1 Sub Base:

(ii) G.S.B. 125 mm

(With non-conventionalmaterial)

2 Base Course:

(i) WBM Grade – II 75 mm

(ii) WBM Grade – III 75 mm

3 Surfacing:

20mm PMC and Seal Coat

5. Conclusion

The physical and strengthcharacteristics of various wastematerials like Marginal material wereexamined in laboratory and the resultswere found to be within the specifiedlimits as per MORTH. Salient outcomesof the study are enlisted in followingsection.

The use of marginal materialsalong with local soil/ mixed in designed

N = 1 = 1t = Duration of harvesting season indays= 65Before opening of the traffic = 318Λ x(1+r) Λ x = 318 x (1+0.06)Λ4ADT = 401r = assuming an initial growth rate = 6%x= Years before opening of the road totraffic = 4Proportionate HCV & MCV out of theADT(SWC may be converted into LadenMCV (1 SWC = 2 Laden MCV)As per clause 3.4.6 of IRC:SP:72-2007HCV(L)-1x401/262 = 1.5HCV (UL)-1x401/262 = 1.5MCV(L)-17x401/262 = 26.0MCV(UL)-10x401/26 = 15.3TOTAL = 44Commercial Vehicles per day (CVPD)for Design

As per Traffic Census, Proportionof Laden &Unladen vehicles areapproximately equal in no. (Sec. 3.4.4)

ESAl per day, To

= 1.5x 2.58 + 1.5 x 0.31 + 26 x 0.31 +15.3 x 0.02 = 12.70

Cumulative ESAL

= T0x 365 x [{(1+r)n-1}]/r] x L

application, N

= T0 x 4811 x L

= 12.7 x 4811 x 1

N = 61,100

Where, T0 = ESAL per day = numberof commercial vehicles per day in theyear of opening x VDF = 12.7

L= Lane distribution factor;

L= 1 for single lane/intermediate lane=1

r = Annual growth rate of commercialvehicles (In%) = 6 %

Vehicle Damage Factor (VDF)Vehicle Type Laden Unladen/

PariallyHCV 2.58 0.31MCV 0.31 0.02

25Indian Highways, September 2016

proportion proves its worth for use in GSBlayer. The designed marginal material(trial mx B) consist of 30% soil/ Moorum,25% Kankar, 25% gravel, 20%Construction and Demolition waste. Thedesigned thickness reduces from 175mm to 125 mm whereas the CBR valueincreases from 4.43 to 6.03 thus saving50 mm depth in overall pavementthickness.

From the above, it can be inferredthat use of locally available marginalmaterials needs to be accorded itsrightful place for construction ofmoderate traffic volume rural road.Considerable saving in construction costand slowing down of environmentaldegradation can be achieved by adopting

use of marginal materials. In the presentwork the benefit of using marginalmaterials is two fold. Number one thereis reduction of 50 mm thickness inpavement layer and number two there issaving of scarce natural resources fromfurther exploitation.

References:

• “Use of Marginal Material in RoadConstruction Editorial, Indian Highways,vol. 26, No. 26, Aug 1998. pp 3-4.

• Ministry of Road Transport & Highways,Fourth Revision (2001).

• Portas S; 2004; Case Study: MechanicalReliabilioty of Sub-grade Layer Built withDemolition waste materials; 2nd

International Congress on NewTechnologies and Modelling Tools forRoads, Societa Italiana Infrastructure

Viarie, Florence, Italy.

• Cook JR, Bishop EC, Gourley CS andElsworth N E, Promoting theuse ofmarginal materials’, Published by TRLlimited, 2001

• Indian Roads Congress SpecialPublication 72, ‘Guidelines for desing offlexible pavements for low volume roads’,2007

•NRRDA, Ministry of Rural Development,Government of India, ‘Quality AssuranceHandbook for Rural Roads’, 2007

• Rollings R R, ‘Substandard Materials forPavement Construction’, ARRBProceedings, Volume 12, Part-7, 1984

• Alvin H Meyer and Hudson W R,‘Preliminary Guidelines for MaterialRequirements for Low Volume Roads’, 4th

International Conference on low Volumeroads, TRR 1106, 1987 �

INDIAN HIGHWAYS SEPTEMBER 2016