Concrete Pavement – Initiatives in India

7/30/2019 Concrete Pavement Initiatives in India

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CONCRETE PAVEMENT INITIATIVES IN INDIA

R. K. Jain*

Ashutosh Gautam**

Abstract

This paper describes the Plain Cement Concrete Pavements being constructed in India in various

climatic zones with temperature variations from 4oC to 47oC, annual rainfall from 500 mm toover 2,000 mm, with the relative humidity from 10% to 92%. The pavement construction isbeing executed with the most modern slip form pavers imported from USA and Germany onhigh traffic corridors and semi mechanised methods on village access roads. The pavers havebuilt-in automatic dowel bar and tie bar inserters and auto float to iron out the surfaceirregularities. Pavements in a length of over 2000 km have been completed and opened to traffic.These are now under performance evaluation. A few case studies indicating projects, typical mixdesigns, problems faced and solutions attempted have been presented.

Introduction

The rigid pavements being constructed in India are mostly Plain Cement Concrete Pavements

with dowel bars at contraction and construction joints. The expansion joints are provided only atthe junction of the pavement with a bridge deck slab or approach slab. The pavement normallycomprises of a tied shoulder 1.50 m wide along the outer slow lane, 2 x 3.5 m wide traffic lanesplus 0.25 m extra width (shyness) beside a barrier type kerb next to the central median. The sub-base comprises of a layer of roller compacted Dry Lean Concrete (DLC) having 10 MPa 7 daycompressive strength. It is separated from the pavement by a 125 micron thick polythene sheet.The thickness of concrete pavements varies from 300 to 340 mm. Contraction joints are providedat 4.5 m centre to centre. There are two longitudinal joints, one in the centre of the traffic lanesand the other along the inner edge of the tied shoulder. See figure 2

The design and construction of cement concrete pavements in India is governed by thefollowing publications of the Indian Roads Congress:-

IRC:SP: 49- Guidelines for the use of DLC as sub base for the rigid pavements. IRC:15 - Standard Specifications and Code of Practice for Construction of

Concrete Roads.

IRC:43 - Recommended Practice for Tools, Equipment and Appliances forConcrete Pavement Construction.

IRC:44 - Guidelines for Cement Concrete Mix Design for Pavements.

IRC:57 - Recommended Practice for Sealing of Joints in Concrete Pavements.

IRC :58 - Guidelines for the Design of Plain Jointed Rigid Pavements forHighways.

IRC:SP:17- Recommendations about Overlays on Cement Concrete Pavements.

IRC:SP:76- Tentative Guidelines for Conventional, Thin and UTWT. MORTH- Specifications for Road and Bridge Works (Fourth Revision-2001).

* Technical Advisor Indian Roads Congress New Delhi and Former Chief Engineer Haryana PWD B&R, Life Member IndianRoads Congress and Member ISCP, Co-convener Rigid Pavement H-3 Committee # 452 Sector-14 Sonipat 131001 (Hr) IndiaPhone: +91 94160-12556, Email: [email protected].

** General Manager (Technical) and Project Director, National Highways Authority of India, Kanpur (World Bank Projects),India; B.Tech, M.Tech (I.I.T. Delhi, Gold Medalist); Life Member Indian Roads Congress; Guest Faculty (Summer Camp) I.I.T.Kanpur, India. email: [email protected]. Phone: +91-99351-42669.

9th International Conference on Concrete Pavements, San Francisco, California, August 17-21, 2008

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Brief History of Cement Pavement Construction in India

The first Plain Cement Concrete (PCC) pavement was built in 1928 in the city of Hyderabad, in1936 in Delhi and along Marine drive Bombay in 1939. The method of construction used to beby manual/semi mechanized means. Concrete used to be poured between wooden/steel formsand vibrated. The practice was panel-to-panel construction or alternate panel construction withpaper-thin butt construction joints. Pavements constructed were about 200 mm thick.

The PCC pavement construction was eclipsed during the 1970s and 1980s by inadequatecement production in the country. Subsequently, after deregulation of the cement industry,interest again grew in construction of PCC pavements. In early 1990 the first mechanized (slipform) pavement construction was initiated by the Ministry of Road Transport and Highways(MORTH), Government of India to pave 80 km of National Highway No.2 (Delhi MathuraRoad). Carriageway width was kept 7.0 m with 1.5 m wide flexible paved shoulder. The Britishspecifications were followed for the construction of the pavement. The project was funded by theAsian Development Bank (ADB). The first slip form paver was imported from Gomaco, USA inlate 1992 and the paving work started in early 1993.

The supervision consultants were two Joint Ventures (one for each state) including Indian, US,

British and Australian consultants. Experts were also engaged to support these Joint Venture .The project was completed in May 1997. The work was completed behind schedule due to initialteething troubles and lack of experience in mechanized construction of cement concretepavements. However the new road provided a good riding quality.

Encouraged by the success of the project, MORTH, Government of India through NationalHighways Authority of India (NHAI) embarked upon a huge programme of construction ofcement concrete pavements under the National Highways Development Program (NHDP) to beimplemented. Some of the State governments and city municipal corporations also cameforward, and evinced interest in construction of Cement Concrete Pavements.

Initiatives - Current ProjectsThe technology got paradigm shift from manual/semi-mechanized to fully mechanizedconstruction. In 1990 the first seminar was organized by the MORTH and interest was aroused inCC pavements. The various initiatives taken since then and subsequent improvements arebrought out here:

Research and Development (R and D)

The validation of temperature gradient across the depth of the slab is an issue in India. TheMORTH has recently entrusted a study to the Central Road Research Institute (CRRI) NewDelhi to validate the temperature gradient between the top and the bottom of the slab by actualmeasurements in all six regions of the country. The work of installing the sensors has recently

started at some sites. The structural evaluation of existing pavements also forms part of thestudy. The research study will be completed within two years.


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Preparation of Detailed Project Reports (DPRs)Packages of 40 to 60 km length costing about Rs. 3,000 to 4,000 million(US $ 75-100 million)were adopted. CC pavements totaling more than 500 km in length were sanctioned in the DelhiKolkata arm of the Golden Quadrilateral. The JVs of International and domestic consultantsprepared the DPRs.

Equipment upgrade

The Government of India removed customs duty on the import of road construction equipment in1997. Interest free mobilization advance towards equipments purchase was also provided tocontractors. Both theses strategies resulted in import of full width pavers, high capacity (250cum/hour) concrete batching plants, chilling plants and a good number of concrete placers, conecrushers (photo 1), sensor operated texturing and curing machines, and concrete saw cutters fromreputed firms in Germany, USA and other countries.

Specifications-Review

The design and construction specifications for Joint Plain Cement Pavements were revised by theMinistry and IRC in 2001-02. The NHAI and the IRC are now working together to develop newguidelines/manuals for design, construction, maintenance and data collection formats under a

World Bank sponsored study to develop documentation to support CC pavements technology.A JV of international and domestic consultants has already started working on the project whichis likely to be completed by July 2009. The design life now been adopted is 30 years (instead of20 years earlier).

Upgradation of Construction Technology

The use of granular sub base as drainage layer over well compacted sub grade (CBR 7 % to 10 %) has become mandatory. 150 mm thick DLC 10 MPa at 7 day is laid. 300 to 340 mm thick CCpavement are being built in 8.75 m width in one go and one lift with sensor controlled slip formpavers. Earlier it used to be fixed form construction. Use of plasticizer, super plasticizer and airentraining agents and curing compound has become common and is essential for Pavement

Quality Concrete (PQC). With the use of slip form paver, a progress of about 300 m to 800 m perday has become possible. The use of high capacity batching mixing plants and 10 tonne to 25tonne tipping trucks for transportation of concrete has revolutionized the paving technology. Theconcrete tied shoulders are being constructed instead of flexible paved shoulders. The JVs ofIndian and Foreign Contractors are executing the projects. This is enhancing the capacitybuilding of Indian Contractors. Some of the Indian Contractors have won contracts in middleeast countries.

Pavement Design.

Structural design of pavements in India takes into consideration the flexural strength (two pointloading) and is performed using the method described in IRC-58:2002 - Guidelines for the

design of Plain Jointed Rigid Pavements for Highways (Second Revision). The computation ofdesign stresses for the edge load condition is done by a computer program IITRIGID developedat the Indian Institute of Technology Khargpur. These guidelines also take into consideration thefatigue life (stresses ratio method) as described by the Portland Cement Association (PCA) ofUSA and temperature stresses but do not consider faulting, smoothness of the pavement, erosionand moisture effects from sub grade. These days cement concrete pavements are being designedwith a flexural strength in the range 4 to 4.5 MPa. In one of the recent projects the pavement has


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been designed with a flexural strength of 4.5 MPa using 43 grade cement. The average 28 daysflexural strength achieved is 5.8 MPa with a Standard Deviation of 0.282 MPa.

The factors governing the design are: single and tandem axle loads, number of their repetitions,tyre pressure, lateral placement characteristics of commercial vehicles, the design of dowel barsand tie bars. Flexural stress is computed due to the placement of single and tandem axle loadsalong the edge.

The legal axle load limits in India have been notified as 10.2, 19 and 24 tonnes for single axles,tandem axles and tridem axles respectively. The load safety factor is taken as 1.1 to account forof unpredicted heavy truck loads.Mix design

The concrete mix design follows the recommendations of IRC: 44- Guidelines for CementConcrete Mix Design for Pavements.The standard lays down the guidelines for proportioningconcrete mixes as per the requirements using the concrete making material including othersupplementary materials identified for this purpose. The proportioning is carried out atappropriate workability of fresh concrete, to achieve specified characteristics at specified age,

and durability requirements. The Standard Deviation (SD) is first determined by testing theflexural strength of more than 30 samples of beams in the laboratory. It is further modified asmore tests on flexural beams become available as the paving work progresses. Mix Design ofDLC is done as per IRC: SP: 49. The Concrete is no-slump concrete with 5 to 6% water content .The density to be achieved has been prescribed as 97%. The gradation of mix for PQC and DLCis as per grading envelope given below.

Sieve Designation Percentage by weight passing the sieve

26.50 mm 10019.00 mm 80-1009.50 mm 55-75

4.75 mm 35-60600 micron 10-3575 micron 0-8


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Table 1

PQC Mix design of a project presently under execution is as under.

Specifiedlimits

Proportion in percentageIndividual Gradation(percentage passing)

20mm 10mmcrushedsand

riversand

PQCmix% ageassing IS:383

Limits

ISSeivesize inmm

20mm 10mmcrushedsand

riversand

33% 27% 6% 34%

40.0 100 100 100 100 33.0 27.0 6.0 34.0 100 100

20.0 91.7 100 100 100 30.3 27.0 6.0 34.0 97.3 95-100

4.75 3.6 9.50 98.2 93.8 1.2 2.6 5.9 31.9 41.5 30-50

0.600 0.0 0.0 45.8 39.2 0.0 0.0 2.7 13.6 16.3 10-35

0.150 0.0 0.0 17.7 2.8 0.0 0.0 1.1 1.0 2.0 0-6

CONCRETE MIX DESIGN WITH FLY ASH NH-4 SATARA - KOLAPUR ROADSI. No Description Sources/Brand Qty/Cum Remarks

1 Ordinary PortlandCement 43 grade

Rajashree ACC 292.50 kg

2 Fly Ash Pozzocrete -63-Dirk India Ltd.

97.5 kg

3 Sand i) Krishan Riverii) Crushed sandfrom 225 TPH.

773.53 kgNatural sand andcrushed sand used in theratio 60:40 (conformingto zone II, IS 383)

4 Course Aggregates . 10mm

Shendre 478.48 kg From 225 TPH crusher

5 Course Aggregates . 20mm

Shendre 811.33 kg From 225 TPH crusher

6 Admixture FOSROC CONPLAST RMCP333 M1

2.45 kg 0.63 % by wt ofcementacious material

7 Water Locally available 144.30 lit W/C ratio = 0.37


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Preparation of Sub Grade:The sub grade is compacted to 97 % Modified Proctor Density in the top 500mm thickness to thespecified lines and levels with selected soil having CBR not less than 7%. The K value test wasdone on the subgrade for the first project in 1993. Table 2 indicates the comparison of CBR, K-Value as per equivalency table in IRC: 58:2002. The values actually obtained are indicated.These days only CBR tests are conducted.

Table 2. Validation of CBR-K Value relationship

Sr. No. CBR percent, bydynamic method

K-Value as perIRC:58:2002

K-Value actually obtained bytest at site.

1. 35.40 10.50 10.01

2. 36.49 10.50 13.53

3. 35.76 10.70 14.71

Provision of GSB/ Drainage layer

The Granular Sub Base GSB as drainage layer is provided with a thickness of 150 mm over theprepared sub grade with material having draining co-efficient not less than 20 m per day. Thegradation envelope prescribed by MORTH Specifications is adopted with some modification.The Plasticity Index PI of the fraction passing the 425 micron sieve is not more than 6 %.Table 3 gives the modified gradation adopted on the projects.

Table 3 GSB /Drainage layer gradation envelope

CBR Value (minimum) 30%

eveisSIehtgnissapthgiewybtnecrePeveiSSI

001mm0.57001-08mm0.35

09-55mm5.62

56-53mm05.9

55-52mm57.4

04-02mm63.2

)deifidom(51-01mm524.0

)deifidom(5-3mm570.0


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Material Characterization

Coarse Aggregates: Clean, hard, strong, dense, nonporous and durable pieces of crushed stoneor crushed gravel and are devoid of disintegrated, soft, flaky, elongated, angular or splinterypieces. The following requirement need to be met.

i) Los Angeles Value : 35 percent maximumii) Aggregate Impact Value : 30 percent maximumiii) Water Absorption : 2 percent maximum

(When aggregates upto 2% water absorption are not available, in extreme case waterabsorption upto 5% is permitted only when aggregates are innocuous)

Fine Aggregates: The fine aggregates consist of clean natural sand or crushed stone sand or acombination of the two and each individually conforms to Indian Standard (IS) : 383. FineAggregates are free from soft particles, mica, organic and other foreign matter. The fineaggregate do not contain the following substances beyond the limits indicated:

i. Clay lumps 4 percent maximumii. Coal and Lignite 1 percent maximum

iii. Material passing IS sieve 75 micron 4 percent maximum natural sand15 percent maximum crushed sand

Figure 1. Cone crusher installed at quarry site to get good quality aggregate

Fly Ash as per IS: 3812-2003i) Content : Not to exceed 35 percentii) Replacement of Cement : 20-21 %

iii) With blended cements : No Fly Ash

Cement(any one of the following five types)i) OPC 33 Grade IS:269ii) OPC 43 Grade IS: 8112iii) Portland Blast Furnace Slag Cement IS: 455iv) Portland Pozzolana Cement IS: 1489v) OPC 53 Grade (used only when part


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of cement is replaced with fly ash) IS:1226Water: It should conform to requirements of IS: 456. Normally potable water was found to besuitable for construction and curing.

Production: The concrete is produced in centrally located batching mixing plant in which everyoperation i.e. weight of aggregates, quantity of water, quantity of plasticizer and quantity ofcement is computer controlled. Most of the plants in use in the country are in the range of 200 to250 cum per hour capacity. Air entraining agent is added if so specified by the designer.Plasticizer is added so as to have a slump of 3015 mm at paving site. The slump at the plant isincreased accordingly.

Transportation: To minimize segregation, loading in tipper is done by moving the tipperslightly back and forth to avoid a big heap. Each tipper is given a serial number and is coveredwith thick canvas to prevent evaporation of water from the mixture during transportation.

Construction Practices

The pavements are constructed as per guidelines contained in IRC 15:2002 and MORTHspecifications 4

threvision 2001. Availability of ready front has to be ensured for optimum

utilization of paving train. Construction of concrete pavement is more of an art than a technique.Paving PQC is a logistical exercise requiring synchronization of several operations before thepavement is produced. The progress has to be consistent with quality.

i) The plain jointed cement concrete pavement generally comprises of pavement qualityconcrete (PQC) with flexural strength of 4.00 MPa (M-35) to 4.5 MPa (M-40) gradeand thickness varying from 300 mm to 340 mm. They are constructed with state-of-the-art full width slip form pavers manufactured by the likes of Gomaco and Guntert-Zimmerman USA, Writzen Germany, etc. Each pavement is generally 8.75 m wide(1.5m tied paved shoulder and 2 x 3.5m wide traffic lanes with an untied kerb andgutter providing additional 0.25m shyness strip along the edge of the central median)

see figure 2.ii) The compacted sub grade having CBR in range 7 % to 10 %, is over laid with a 150

mm thick granular drainage layer followed by a 150mm thick layer of dry leanconcrete (DLC) having a minimum compressive strength of 10 MPa at 7 days. Thedensity of the laid concrete is not to be less than 97% of dry density achieved duringtrial lengths at site.

iii) The separation membrane of 125 micron thickness polythene sheet is used betweenthe DLC sub-base and the PQC base. The doweled contraction joints are generallylocated 4.5 m apart and a construction joint at the end of the day. The expansionjoints which were earlier being located at spacing of about 300m are not beingprovided now except those abutting to structures. The longitudinal joints are provided

in the centre of the two traffic lanes and other for 1.5 m tied shoulder at the edge ofslow lane. The transverse joints have plain steel dowel bars 32 mm to 36 mmdiameter and 500 mm long. The longitudinal joints have ribbed steel tie bars 16 mmdiameter and 550 mm long . Mostly the transverse texturing is done. However in caseof NH-28 project longitudinal tinning has been adopted. Joints cutting are in twostages i.e. initial groove and thereafter widening and deepening. The joints are sealedas per procedure laid down in IRC:57: 2006. The Manufactures instructions arenormally followed.


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iv) The construction of CC pavements has been done in all climatic zones of the country.In the Kanpur-Allahabad road in Uttar Pradesh the highest temperature reaches up to42 C , the lowest down to 2C and annual rainfall is about 1500 mm. The State ofRajasthan lies in arid and semi arid region where temperatures reach up to amaximum of 47 C and drop to minimum of minus 4 C, annual rainfall is less than500mm. The relative humidity drops to less than 10%. In Assam State the maximumtemperature reaches 40 C and the minimum 5 C and annual rainfall is about 2500mm. Tamil Nadu State is in tropical wet and dry region where the range oftemperatures is between a maximum of 44 C and the minimum only 14 C, annualrainfall is about 2000 mm. The temperature of concrete is kept below 30 C bypaving in the night and the use of ice flakes/chilled water prepared in the chillingplant.

v) JPCP pavements are also being built with manual / semi mechanized methods. Streetsin the larger towns and villages are also being paved in concrete with manual /semimechanized construction, when quantum of work is small and highly mechanizedoperation are not cost effective.

vi) Only one project on NH-4 Satara Kholapur Road has been constructed using fly ashcontent of 25% to 30% of cement required. The designated flexural strength and

compressive strength requirements were met. The performance is under watch. Themix design is available in table 1.

vii) Examples of pavements completed in the year 2007 are shown in Figure 3.

8.750(rigid pavement)0

330 thk. PQC150 thk. DLC150 thk. DL500 thk. SG

1.

00

1.

50

7.

25

-3.0 %-2.0 %

2.

1

Figure 2. Typical Cross-section of a CC Pavement in NHDP


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Texturing and Curing: is done by an integrated machine performing the dual function oftransverse brush texturing and spraying liquid aluminized flakes based curing compound. Watercuring by wet burlap and ponding is continued for 7 days. In case of NH -28 longitudinaltexturing has been adopted on the advice of the World Bank expert (Figure 3).Texture depth for transverse texturing = 31000D2 where D is the diameter of the sand patchcircle in mm. It varies from 0.75 mm to 1.25 mm depth. On roads in villages and in municipaltowns, the texturing is done by hand held brush (Figure 3).

Joints cutting and sealing: The transverse contraction joints are cut with joint cuttingmachine. The crew enters the PQC surface when it is neither too soft nor too hard and iscapable to bear the weight of machine and the crew. The transverse joints and twolongitudinal joints are sealed with polysulphide or silicone or polyurethane as perIRC:57:2006.


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Figure 3.: Texturing on fresh pavements

Transverse texture, September 1994 Longitudinal Texture, February 2008

Water Curing by wet burlap Curing by water pounding

Hand held brush texturing on NagpurMunicipal city Road January, 1997.

Completed pavement, 2007


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Ride Quality

India has set standard of achieving a roughness index of less than 2200mm/km for CCpavements as per the acceptance criteria specified in IRC:SP:16-2004. The NHAI commissionedCRRI to measure the roughness of the highways constructed under the first phase of NHDP.CRRI surveyed the condition and roughness of the new CC pavements constructed in the GoldenQuadrilateral (joining the four major metros of Delhi, Kolkata, Chennai and Mumbai). Thesurvey was conducted in 2004-05. The pavement construction in both carriageways wasgenerally completed at the time of the survey.

Table 4 Summary of PQC Roughness Survey on Golden Quadrilateral by CRRINote: BI mm/km = 630 x (IRI m/km) 1.12 ---- IRC: SP: 16-2004.

The surface is set to correct alignment, grade and camber. The surface levels are checked on gridpoints at 5 or 6.25m longitudinally and 3.5 m transversely with a tolerance (+) 5 mm () 6 mm.

Description of First Project : The Project Road forms part of Shershah Suri Marg (NH2) andemanates from Rajghat New Delhi (Samadhi of Mahatma Gandhi Father of the Nation). It leadssouthward to Agra, the city of Taj Mahal (symbol of eternal love and one of the seven wondersof the World). It turns eastward and finally terminates at Kolkata. The Project Road is 56 km in

length. The cost at completion of the project (year 1997) was Rs. 1008 million (US $ 25 million).The Gomaco slip form paver with indigenously built concrete placer is shown in Figure 5 a) andthe indigenously built batching mixing plant is shown in Figure 5 b).

a) First Concrete paver with locallymanufactured placer.

b) First Batching Mixing Plant 75 cum/hour.

Figure 5

ItsaFenalretuOwolS nner Lane beside MedianLocations

Roughness IndexBump Integrator BI(mm/km)

InternationalRoughness IndexIRI (m/km)

Roughness IndexBump IntegratorBI (mm/km)

InternationalRoughness indexIRI (m/km)

A) 2112 2.95 2097 2.93

B) 2310 3.19 2373 3.26


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Table 5

Brief Technical Particulars of the first JPCP Project

1. Width of the pavement 7.0 m

2 Width of the flexible Shoulder 1.5m

3 Width of the earthen shoulder 1.0m4 Sub Grade 95 % modified Proctordensity and CBR 7%.Crust Thickness :-Dry Lean Concrete (DLC)Polythene separation SheetPaving Quality Concrete (PQC)

500 mm

150mm thick M 10 at 7 days125 micron thick300mm thick M 40 at 28 days

5. Transverse Contraction Joints 8mm wide at 5.0m intervals.

6. Longitudinal Joint 5mm wide-only in first 13.16 km length.In balance 33km longitudinal Joint notwidened and not sealed.

7. Joint Sealant Polysulphide-based cold poured8 Central verge width 5m reduced to 1.5m in tight locations

9 Service Roads 11 km long flexible pavement in urbanareas.

Mix Design (mix design) - DLC

Size of Aggregate Mix original designQuantity per cum

Modified designQuantity per cum

liNgk055mm02-04

%03-gk066gk044mm01-02

%03-gk066gk055mm50-01

%04-gk088gk066mm50-00

Water 5.4 % by dry wt of aggregatesincluding weight of cement.

Variation in quantity ofwater

+ 2%- 0.5 %

Cement OPC 33 grade 150 kg/cum

Cement : aggregates 1:12.66 aggregates against 1:15

Averages strength of 5cubes.

aPM2.71aPM.2.02


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Mix Design of PQC.

Sr.

No.

Item Quantity in Kg per cum

original quantities modified quantities on advice ofDr. Good Speed, University ofNew Hampshire USA.

1 Stone Aggregates

20-10mm10-05mm05-00mm

630kg (35 %)520 kg (29 %)645kg (36 %)

Changed to 34 %29%, and37 % for better density

2 Water 176 liters/cum

3 Cement Grade 53 400 kg/cum

4 Plasticizers 1.2 liter i.e. 0.3 percent by weight of cement ( vary from0.25 % to 0.60 % in winter and summer respectively)

5 Water Cement Ratio 0.44

6 CharacteristicCompressiveStrength

40 MPa

7 i)

ii)

Workabilitymeasured as slumpas per contractspecifications.Actually enforced atsite and it gave verygood workability

20 mm + 10mm at paving site

15-20 mm in winter18-25 mm in summer

8 Compaction factor 0.82+ 0.03 in a days work.

9 Concrete produced 1.5 cum per batch

10 Time taken 1.5 minutes/ batch

11 53 grade Portlandcement used

400kg/cum

12 Water + Plasticizer 170 liter water + (6 lit water + 1.2 lit of plasticizer) withdaily adjustment of moisture content present in theaggregates.


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Quality control Tests

The MORTH specifications have introduced the concept of building in quality assurance into theexecution of every aspect of the construction. However this concept is new in India as is the roleof the supervising Engineer under the FIDIC form of Contract. So it has been found necessaryfor the supervision Consultant to exercise very stringent Quality Control (QC) whilst supervisingthe sampling and testing in the contractors site laboratory. The QC tests are conducted on thestone aggregates, water, cement, DLC and PQC. Pre construction, routine construction and postconstruction tests are performed. It is the responsibility of the supervision Consultant to ensurethat the tests specified in the Contract document are always conducted at the desired frequencyand that the results obtained meet the minimum specified values.

The essential quality control tests which are performed are listed in the following table.

Table 6: List of Quality Control Tests Performed on PQC

Pre -Construction Tests During Construction Post Construction

1. Gradation of aggregates2. Strength of cement3. AIV/LA of aggregates4. Water absorption of

aggregates5. Innocuousness of

aggregates/AlkaliAggregate reactivity

6. Quality of water to beused for construction/curing

7. Adhesion of sealant8. Test on efficacy ofplasticizer

1. Workability of concreteby slump test

2. Filling of cubes/beamsfor subsequent strengthtests.

3. Testing trueness of stringline of the paver

4. Vibration of vibrators ofpaver

5. Adjustment of auto-float6. Trueness of forms where

fixed form technique isused7. Dowel bar alignment

testing at transversejoints (random testing)

1. Strength through cores2. Thickness of pavement

and homogeneity bycoring

3. Surface level4. Surface regularity by 3m

straight edge or movingstraight edge

5. PQC surface smoothnesstesting based on theIRC SP:16-2004. (not

>2200 mm/km).equivalent InternationalRoughness Index (IRI)calculated.

6. Texture depth by sandpatch method

7. Cracking, Slabs with thecracks deeper than halfthe slab thickness are tobe replaced.

Additional testing to establish a database has started including:- pavement friction testing toidentify texture types that provide durable texture, and deflection testing using a Falling WeightDeflectometer (FWD) to provide baseline data on the structural capacity of the newlyconstructed pavements.


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Documents

Concrete Pavement – Initiatives in India