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Agenda

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4

CONDITION OF ROADS TODAY.....

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Facts & Problems........

80 - 90% of National & State Highways are not structurally

adequate for permissible axle load of 10.2 tones.

- (World Bank Estimate) Maintenance of existing roads has not reached even 50-55%,

19,250 Kms of NH require Strengthening - Cost of about 14,450

Crores & about 10 to 15 years.

- Tenth Five Year Plan

1951 1999

Length (Million Kms) 0.4 3.3 (Eight Fold)

No. of vehicles 0.3 50 (170 fold)

ROAD TRANSPORT FOR THE PAST 50 YEARS

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Facts & Problems........Requirement of Road Strengthening

Riding Quality of Indian Roads is very poor.

(Average Roughness by Bump Integrator is - 4600 mm/km - as

compared to 1500 - 2000mm/Km for bituminous roads)

India loses about 20,000 - 30,000 Crores every year due to

surface roughness & Vehicle operating costs

2001-2011 2011-2012

Length (Million Kms) 30,000 40,000

No. of vehicles 22,000 30,000

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New Road Construction

Conventional concrete pavements are

justifiable on life cycle cost and have high

initial cost.

High construction time.

Surface Technologys development with

concrete for pavement seeks to address the

above issues

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High Tensile Strength Concrete For RigidPavement Applications For New roads

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Conventional pavement quality concrete aregenerally designed for M40 GRADE, targeting aflexural strength of 4.5 MPa at 28 days.

With this flexural strength, designed pavementthickness arrives in the range of 275 300mm,depending upon the traffic volume and load.

Use of conventional concrete in rigid pavementsresults in higher initial cost in comparison to itsbitumen counterpart.

Current Practice

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The road aheadCurrent scenario-An Introduction

Development-the road ahead

UTWT-Theory & Benefits

SSC Technology

Design Considerations

Cost Benefit

Composition

Optimization of Concrete Pavements in Rural Roads

FAQs

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Development Summary

We have developed mix design that has hightensile / flexural strength.

This leads to lower thickness of pavement /reduced material requirement.

Placing and curing regime adopted speeds uptime for opening to traffic.

Economics are at par with bituminous optionfor the new road.

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Mix design was made incorporating conventional

ingredients to keep the cost low.

Water cement ratio was targeted as low as

possible by incorporating a chemical admixture

and additives giving the required workability and

retention.

Maximum size of aggregate was kept as 12.5 mm.

Methodology Adopted

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Field Observations A stretch of 1400 sq.meters of high tensile strength concrete

pavement was constructed at Jharkhand cement works(June-

2005) to monitor its field performance

Showing excellent texture and finishing

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Field Observations

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UTWT-Theory & BenefitsCurrent scenario-An Introduction



SSC Technology


Cost Benefit

Composition


FAQs

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What is white topping?White topping is a concreteoverlay constructed on top of an

existing bituminous pavement.

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White toppings

Consists of thin concrete layer on top of an

existing asphalt pavement

Specific steps are taken to bond the new concrete

to the existing bituminous surface and to cut shortjoint spacings.

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White toppings

White topping a concrete overlay usually 100

mm thick or more placed directly over an old

bituminous road Ultra thin white topping - a concrete overlay,

100mm thick or less placed on a prepared

bituminous surface to enhance bond between

bitumen and concrete. Have short joints

Concrete Inlays

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Thickened Edge for WT

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Bonding Effect on Edge Stresses

Unbonded Bonded

8.49 Mpa 2.90 MPa

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Short joint spacing allows the slabs to deflect instead of bend.

This reduces slab stresses to reasonable values

0.6m 0.6m o.6m 1.8m

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Effect of AC Thickness

50mm Ac 100mm AC

Concrete Stress,MPa 5.73 3.68

AC Strain 50mm Ac 100mm AC

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Traffic & Design Commercial vehicles count are important

Greater pavement thickness for industrial

areas, truck parking, loading areas Thinners section if heavy vehicles are are

less.

Design period is for 15 years

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Surface Technologys White Topping

Ultra thin white topping - a concrete overlay,

100mm thick or less placed on a prepared

bituminous surface to enhance bond betweenbitumen and concrete. Have short joints

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Concrete Inlays

A concrete overlay placed in a trench milledout of a thick bituminous pavement.

No need to raise grade significantly

Costs associated with grade increaseeliminated , these include additional shouldermaterials, guard rail adjustments, medianbarrier, signs ; matching grade adjustments at

intersections and ramps.

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White Topping -Benefits

Can be provided on pavements in bad

condition little no pre overlay

preparation is needed

Avoids reconstruction problems.

Improves structural capacity

Maintains high level of serviceability( ability to carry traffic)

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White Topping - Benefits

Bituminous surface becomes brittle due to UV

rays and cracks allowing ingress of water leading

to pavement failure. Stripping action of water breaks the bond

between aggregate and bitumen leading to

pothole formation.

Reflective cracking on bituminous overlay

decreases pavement life. Not so with concrete.

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White Topping - Benefits

Strengthens the deteriorated bituminous

pavement, extending the service life of the

pavement.

Provides a smooth ride that can significantly

improve the functional life of the pavement.

Utilizes the existing bituminous pavement

as a solid base course, providing stability.

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Opening The Road to Traffic

72 hrsfrom the time the laying is completed

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Why Is WT Not Popular in India?

WT thickness is 180-200mm and is 3 timesthe cost of bituminous overlay. ( based onTMC data).

Due to high cost difference , WT is notpopular.

The time for construction is high compared

to bituminous construction leading tolonger traffic disruptions.

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Surface Technologys White Topping

Surface Technology has been working to

remove these impediments and developedSurface Technologys white topping.

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SCC TechnologyCurrent scenario-An Introduction



SSC Technology


Cost Benefit

Composition


FAQs

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Originally developed in Japan, SCC technology was

made possible by the much earlier development of

super plasticisers for concrete. SCC has now been

taken up with enthusiasm across Europe, for bothsite and precast concrete work. Practical application

has been accompanied by much research into the

physical and mechanical characteristics of SCC and

the wide range of knowledge generated has beensifted and combined in this guideline document.

About SCC technology

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Self-compacting concrete (SCC) has been described as "the

most revolutionary development in concrete construction for

several decades". Originally developed to offset a growing

shortage of skilled labour, it has proved beneficial

economically because of a number of factors, including:

aster Construction

Reduction In Site Manpower

Better Surface Finishes

Easier Placing

Improved Durability

Greater Freedom In Design

Thinner Concrete Sections

Reduced Noise Levels, Absence

Of Vibration

Safer Working Environment

What Is SCC Technology?

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Table : List of test methods for workability properties of SCC

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Table 2: Workability properties of SCC and alternative test

methods

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Table 3: Acceptance criteria for Self-compacting

Concrete.

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Figure A.2 Flow cone and table to determine the

relative slump - flow G p

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Figure A.3 V-funnel to determine the flow

time of the mortar

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ANNEX B: CHECKLIST

The Checklist has been designed to aid Specifiers, Producers and Contractors in

ensuring that all key elements of a SCC application have been considered ahead of thework starting.

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43

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45Table C.1b: Fault-finding for high results

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46Table C.2: Possible corrective actions from identified faults

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47Table C.2: Possible corrective actions from identified faults

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48

Surface Technologys Development

Application locations:

Cement Works Jharkhand cement works.

Kalamboli Warehousing Complex , CIDCO ltd.

Cement plants for quarry roads for

transportation of limestone into the factory.

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50

Cement Works Jharkhand Cement Works.

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Current scenario-An Introduction



SSC Technology


Cost Benefit

Composition


FAQs

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52

Basic Consideration for the Design of White Topping

Support strength of the existing

bituminous pavement

Flexural strength of the concrete The expected service life of the

pavement before any major structural

rehab is required Traffic in terms of commercial vehicles

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53

Support of the existing bituminous pavement

Measured in terms of sub grade reaction ,k

determined by plate load test / derived

from soil type and other sub grade using

the monograms.

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54

Surface Preparation

Shoving , rutting and potholes need to berepaired.

Areas with sub grade failure should beremoved and replaced.

Depending upon the surface distortiondecide to directly clean and place concreteor mill and place concrete.

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55

White Topping (WT) Design AC/DBM bottom strain due to an 8.16 ton single axle

load

AC/DBM bottom strain due to an 16.2 ton tandemaxle load

WT corner top stress due to an 8.16 ton single axleload , kg/cm2

WT corner top stress due to a 16.2 ton tandem axleload, kg/cm2

Additional AC/DBM bottom strain due to

temperature gradient Additional WT corner top stress due to temperature

gradient , kg/cm2

Thermal coefficient of expansion of the PCC

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57

Design Considerations of WT

Bond is critical milled surface is

recommended

Slab size is important (short joints) Underlying asphalt thickness is important

( min 75mm is required)

Attention to mix design is important Placement considerations

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58

Construction Steps for WT

Core existing surface for bituminous

depth.

Mill and clean the surface. Place, finish and cure the concrete.

Cut joints early with early entry saw.

Open to traffic.

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59

Why does White Topping (WT) have such short

joints?

The short joints in white topping areused so that the slabs do not bend

but deflect under wheel load and

come back after the load has passed.

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60

What is the typical lifespan of a white topping

pavement?

White topping pavements can perform

well with little or no rehabilitation for10-15 years with nominal maintenance.

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Road Length and Cost ( TOI:27/09/2005)

1590.34

700

350.82

3200

0

500

1000

1500

2000

2500

3000

3500

km Rs./sqm

Asphalt

Concrete

Typical Road Improvement Costs With

Conventional Technologies

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Surface Technology WT

Cost Effectiveness can be worked out based

on the site conditions.

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SSC Technology


Cost Benefit

Composition


FAQs

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Final Mix Proportion

Final concrete mix proportion arrived

Quantities (kg per cum of concrete)

Cementitious = 530

(cement+mineral)

Water = 180 (w/cementitious ratio = 0.3)

Coarse Agg. = 1000

Fine Agg. = 900

Chemical Adm. = 2.5% by weight of cement (PC based)

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Test Results Of High Tensile Strength

Pavement Quality Concrete

Fresh concrete properties :

Fresh density 2500 kg/cum.

Initial workability = 550 mm flow after 30mins. = 120mm (slump).

Bleeding = 0.030 ml/cm2.

Mechanical properties :

Compressive strength at 3,7 & 28days were 19 ,31 , 57mparespectively.

Flexural strength at 7 & 28days were 5.1& 8.0 MPa respectively.

High performance pavement quality concrete resulted in flexuralstrength which is 14% of compressive strength.

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Durability properties :

Water permeability = negligible. RCPT = 1260 coulombs.

Initial surface absorption = 0.32 ml/m2/s. Abrasion = 1.12mm. Drying shrinkage = 4 x 10-3 mm (length change).

Above results showing all the characteristics of a highconcrete (performance with high flexural strength) best

suited for rigid pavements.

Test Results Of High Tensile Strength

Pavement Quality Concrete

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NEW TECHNOLOGY VS CONVENTIONAL PRACTICE

CONVENTIONAL BITUMINUS ROAD

TYPE COST/M3 THICKNESS Amount, Rs

DBM 5617 50MM 266

BM 4838 75MM 362.8

AC 1313 40MM 52680

BM+AC 415

CONCRETE 5698 300MM 1709

WMM 1211 200MM 242

GSB 1179 250MM 294

2245

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NEW TECHNOLOGY VS CONVENTIONAL PRACTICE

NEW TECHNOLOGY

GROUTED MECADUM Amount, Rs

BM 4768 50MM 238

GROUTE 240

476

UTWT 13000 125MM 1600

50MM 800

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SSC Technology


Cost Benefit

Composition


FAQs

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Design

Adjusting spacing of joint

Selecting proper loadings

Selection of grade of concrete depending on

stresses

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Equipments

Minimum investment

Simple easy to maintain ,least operating cost

Not targeted for high output

Weigh batching mixer of 6 to 8 Cubic meter per hour-3.5 lakhs

Simple good quality screed to get line and level -3.5 lakhs Heavy plate compactor- 1.5 lakhs

Joint cutting- 1.0 Lakhs

Miscellaneous- 0.50 lakhs

Total - 10 lakhs

Output per year 10000 cub meter The cost of owning operation, maintenance etc would be about Rs 40 Percubic meter

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Materials

Specially designed Semi self compact concrete with fly ash to

Get proper line and level with minimum efforts

Vibration not needed making it attractive

Specially developed sealant

GSB/WMM of local material

Or

Separator to avoid joint cutting

Voided concrete as strong base and effective drainage layer

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Flexible Pavement Typical crust

Liquid seal Coat

car et

5 BBM

75 WBM

to 3 GSB

5 Subgrade

Ty ical cost

Rs 46 er square eterabove sub grade

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CONCRETE PAVEMENT

Advantages :

Whole life cycle cost less

Fuel saving up to 20 %

Low Recurring maintenance cost

Improper maintenance of flexible pavement

due to inadequate grant leads to total

deterioration and loss of assets.

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Concrete Pavement-Suggested optimum crust

150 to 160 mm

PQC

M 35 grade concrete

or

M 45 grade concrete

Depending on

design load

Semi self compact

concrete

50mm Voided

Concrete

Or 75mm GSB

Voided concrete with

single size

aggregate

with 2 % cement

GSB as per MonthSpn

500 mm sub grade

Joint spacing of 2.25

To 2.5 m

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Typical Concrete Pavement Cross

Section

Granular Sub Base - 75

Pavement Quality Concrete (PQC)- 160

Subgrade

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Concrete Pavementii) Temperature Stress

It is observed that the temperature stress depends upon the size of the panel,i.e. the spacing of transverse contraction joint. The temperature stresscalculated for rural road for concrete slab width of 15 cm 20 cm consideringa joint spacing of 2.5 m, 3.75m and 4.5 m for the State of Maharashtra are

given as under.Slab Thickness

Cm

Temperature Stress (Kg/cm2)

for joint spacing

2.5 m 3.75 m 4.5 m

15 10.73 23.10 26.75

16 9.61 22.07 26.328

17 8.65 21.14 25.972

18 7.72 20.34 25.639

19 6.83 19.37 25.079

20 6.04 18.21 24.225

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Concrete Pavement

iii) Vehicle Type and Stresses

Most of the cases, the rural roads have a very low volume of traffic, generallyof the order of less than 150 vehicles per day, consisting mostly of ruraltransport vehicles like agricultural tractors / trailers, light goods vehicles,buses, animal drawn vehicles, motorised two wheelers and cycles. Some of

the rural roads may also have light and medium trucks carrying sugarcane,timber and quarry material etc.

Slab Thickness

Cm

Stress (Kg/cm2) due to wheel load

3.0 t 5.1 t

15 24.911 38.758

16 22.609 35.277

17 20.639 32.282

18 18.940 29.685

19 17.461 27.416

20 16.165 25.422

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Concrete PavementFor a Transverse Contraction Joint spacing of 3.75m c/c

Slab

thickness

3.0 t wheel load (Design

condition)

5.1 t wheel load (check)

Stress

due to

wheel

load(Kg/cm2)

Stress due

to

temperatur

e(Kg/cm2)

Combine

stress

(Kg/cm2)

Stress

due to

wheel

load(Kg/cm2)

Stress

due to

temperatu

re(Kg/cm2)

Combine

stress

(Kg/cm2)

15 cm 24.911 23.10 48.011 38.758 23.10 61.658

16 cm 22.609 22.07 44.679 35.277 22.07 57.347

17 cm 20639 21.14 41.779 32.282 21.14 53.422

18 cm 18.940 20.34 39.280 29.685 20.34 50.025

19 cm 17.461 19.37 36.831 27.416 19.37 46.786

20 cm 16.165 18.21 34.375 25.422 18.21 43.632

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Concrete PavementFor a Transverse Contraction Joint spacing of 4.50m c/c

Slab

thickness

3.0 t wheel load (Design

condition)

5.1 t wheel load (check)

Stress due

to wheel

load(Kg/cm2)

Stress due

to

temperature(Kg/cm2)

Combine

stress

(Kg/cm2)

Stress due

to wheel

load(Kg/cm2)

Stress due

to

temperature

(Kg/cm2)

Combine

stress

(Kg/cm2)

15 cm 24.911 26.75 51.661 38.758 26.75 65.508

16 cm 22.609 26.328 48.937 35.277 26.328 61.605

17 cm 20.639 25.972 46.611 32.282 25.972 58.254

18 cm 18.940 25.639 44.579 29.685 25.639 55.324

19 cm 17.461 25.079 42.540 27.416 25.079 52.495

20 cm 16.165 24.225 40.390 25.422 24.225 49.647.

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v) Special type of Sealants for Village Roads:

The magnitude and frequency of vehicular traffic in rural road

is much less in comparison to that of NHs and SHs. So the joint

sealants need not have high elongation value and the

parameters to test adhesion properties may also be lenient.

As the requirements are not very stringent, the cost of

sealants required for rural roads has been found out to be

cheaper by about 25% than that is required for NHs and SHs.

Hence a special testing facility shall be established to assessthe properties of sealants applicable for rural roads.

Concrete Pavement

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Concrete pavement-Alternate to joint cutting

Cost of cutting and sealing joint is about Rs 60

per running meter

By inserting separator element work would be

expedited and at reduced cost-Desirable for

cost optimization

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Rigid Pavement-Optimum cost

For proposed crust details and suggestion made the cost would work out as follows :-

Assumptions Axle Load 5.1 ton

Joint spacing 2.25 meter

Separator with suitable material against joint cutting

Grade of concrete M 45

Cost is Rs 560 per square meter which is 21.74 % above

compared to flexible pavement if elements above sub gradealone are taken. Overall cost would be much less than 15 %

hence within PMGSY norms

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Rigid Pavement-Optimum cost

With reduced axle load

Assumptions

Axle load 3.1 ton

Joint spacing 2.25 m

Slab thickness 15 Centimeter

Grade of concrete M 35

Cost is Rs 535 per square meter which is 16.30 % above

compared to flexible pavement if elements above subgrade

alone taken. Overall cost would be much less than 15 %hence within PMGSY norms

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SSC Technology


Cost Benefit

Composition


FAQs

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90

Is White Topping new?

The first white topping pavement wasreportedly placed in 1918, and has beenused on hundreds of projects. In the 1990s,

new developments to white topping designand construction were made, such as theidentification ofUltra-Thin White topping(UTW) as a pavement type alternative. In the

last 10 years, white topping has beenmaking a comeback as a viable pavingalternative.

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91

What types of white topping are there?

White topping is commonly classified into threecategories:

1.Conventional White Topping,

2. Thin White Topping, or Ultra-thin White Topping

(UTW). The classes are based on the thickness of thenew concrete layer. Conventional white topping isthe thickest, constructed with 200mm or more ofconcrete.

3. Ultra-thin white topping is the thinnest class,

commonly constructed from 50 to 100mm thick.Thin white topping is the intermediate thickness 100 to 200 mm where new opportunities lie to, insome cases, significantly increase the life of anexisting pavement.

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92

What kinds of pavement distresses commonly

occur in white topping?In thinner white topping, such as UTW,

corner cracking is commonly the

predominate distress type. The thickness,

panel size, and HMA type are dominatingparameters driving the rate of cracking.

Larger panels, used in thicker white topping

sections, typically develop other types of

distress, such as mid-slab cracking andfaulting.

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93

When is white topping not an option?

White topping overlays are not recommended when the

existing HMA pavement is badly deteriorated or when

substantial amounts of the existing pavement have to beremoved during rehabilitation. It is not recommended that

white topping be placed over HMA pavements with

material problems, such as asphalt stripping, either.

Pavements with very little deterioration are excellent

candidates for white topping overlays.

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96

Is ultra-thin white topping (UTW) a new technology?

Ultra-thin white topping is a relatively newdesign that emerged in the 1990s. This

class of white topping is designed to bondto the existing HMA pavement, so that thetwo layers act as a composite sectioninstead of as two independent layers. Thisallows the concrete overlay thickness to be

decreased, while still allowing theaccommodating level of traffic loading.

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Is special construction equipment required to construct white topping

pavements?

Conventional slip-form and fixed-form

pavers have both been used successfully inwhite topping construction. Smaller

equipment, such as vibrating screeds, has

also been used.

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utwt 2dec 09

Documents