UNDER THE GUIDENCE OF Dr. P. NANJUNDASWAMY

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LIFE CYCLE COST ANALYSIS OF FLEXIBLE AND RIGID PAVEMENT – A CASE

STUDY

Presented byBharath Kumar. M

Hanumantha MMamatha S

Pooja SVijaya Kumar A C

IntroductionObjectives RBI Grade 81Laboratory studiesPavement design Life cycle cost analysis Results and Discussion

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Contents

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Introduction

Project location

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Objectives of the project

To identify the design requirements for the proposed upgradation of project road.

To evaluate the effect of RBI grade 81 chemical on CBR property of subgrade soil.

To develop electronic spread sheets for designing flexible and rigid pavements for high volume roads as per IRC guide lines using Microsoft excel.

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To design both flexible and rigid pavement structure on treated and untreated subgrade soil as per IRC guidelines using the developed spread sheet.

To perform the life cycle cost analysis for economic evaluation of alternative designs considered

Methodology

Collection of data with respect to present and future traffic scenario on the project road.

Collection of subgrade soil samples from various locations and to evaluate the basic properties needed for classification on and design requirements.

Formulate the procedure for designing flexible and rigid pavement as per the present IRC guidelines and automate the design process by implementing the procedure in an electronic spread sheet (Microsoft Excel).

Implement the process of life cycle cost analysis in an electronic spread sheet for choice of alternative pavement solutions on the basis of economic consideration.

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RBI Grade 81

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Composition of RBI Grade 81

Contents Percentage

Ca 25-45

S 5-15

Si 5-20

K 0-5

Mg 0-10

Al 0-5

Fe 0-5

Zn 0-2

Cu 0-2

Mn 0-2

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Laboratory Studies

Grain size distribution analysis as per IS 1498 : 1970

Atterberg’s limits as per IS 2720 (Part V ) 1985

Modified proctor compaction test as per IS 2720 (part Vlll)

California bearing test as per IS 2720 (Part XVl)

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Tests conducted

Gradation results of untreated subgrade soil

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No. Chainage

Wet sieve analysis

%Gravel %Sand %Silt & clay

1 127-120 2 75.00 23.00

2 128-530 0.40 71.80 27.80

3 129-120 4.80 76.40 18.80

4 132-500 4.80 54.80 40.40

5 134-000 19 80.20 0.80

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Atterberg’s limits of untreated subgade soil

No Chainage LL(%) PL(%)

1 127-120 35.00 21.00

2 128-530 Non plastic soil Non plastic soil

3 129-120 27.50 19.00

4 132-500 33.00 18.00

5 134-000 46.50 23.00

Soil classification of untreated subgrade soil

Chainage Type of soil

127-120Clayey sand (SC)

128-120Clayey sand (SC)

129-120Clayey sand (SC)

132-500Clayey sand (SC)

134-00Well graded sand(SW)

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Moisture density test results of untreated subgrade soils

No. ChainageCompaction Test

OMC (%) MDD (gm/cc)

1 127 - 120 12.50 2.085

2 128 - 530 08.30 2.265

3 128 - 120 09.33 2.060

4 132 - 500 11.30 2..230

5 134 - 000 10.50 2.240

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CBR Test results of untreated subgrade soils

No Chainage CBR(%)

1 127 - 120 4

2 128 - 530 14

3 128 - 120 13

4 132 - 500 7

5 134 - 000 5

CBR Test results of stabilized subgrade soil using RBI grade 81

Chainage % of Stabilizer Curing period CBR (%)

127-120

4

3days

29

6 36

134-000

2

3days

20

4 28

DESIGN OF FLEXIBLE PAVEMENT AS PER

IRC 37-2011(DRAFT CODE)

Flexible pavement design thickness of untreated subgrade soil

CHAINAGE 127-120 128-530 129-120 132-500 134-00

CBR(%) 4 14 13 7 5

TOTAL THICKNESS

770 590 590 645 720

WEARING COURSE(mm)

50 50 50 50 50

BINDER COURSE(mm)

140 90 90 115 120

GRANULAR BASE(mm)

250 250 250 250 250

GRANULAR SUBBASE(mm)

330 200 200 230 300

Flexible pavement design thickness of treated subgrade soil

CHAINAGE 127-120 134-000

% of stabilizer 4 6 2 4

Effective CBR (%) 13 16 14 15

TOTAL THICKNESS

590 590 590 590

WEARING COURSE(mm)

50 50 50 50

BINDER COURSE(mm)

90 90 90 90

GRANULAR BASE(mm)

250 250 250 250

GRANULAR SUBBASE(mm)

200 200 200 200

Design of Rigid pavement as per IRC 58-2010

Rigid pavement design thickness for untreated sub grade soil

Chainage CBR (%) K(Mpa) Thickness(m)

127-120 4 35 0.3

128-120 14 60 0.29

129-120 13 59 0.29

132-500 7 48 0.3

134-00 5 42 0.3

Chainage % of

StabilizersCBR(%)

Effective CBR

K(Mpa)Thickness

(m)

127-120

4 29 15 61 0.28

6 36 16 63 0.28

134-00

2 20 14 60 0.28

4 28 17 63 0.28

Pavement design thickness for treated subgrade soil

LCCA OF FLEXIBLE AND RIGID PAVEMENT

Rate adopted for LCCA

Pavement crust Rate /cu m (Rs)

BC 4762

DBM 4144

WMM 750

GSB1 720

Prime coat 16

Tack coat 10

PQC 3932

DLC 1563

RBI grade 81 30

Total life cycle Cost Estimate for Rigid pavement

Life cycle cost cost (Lakhs)

Initial cost 11789750

Maintenance cost 

Joint seal 682500

Concrete spalling 33600

Texturing 640000

Total 12505850

RESULTS

By addition RBI grade 81 to the untreated subgrade soil at 2%, 4% & 6% increases the CBR value by 300%, 600% & 800% respectively.

In case of Flexible pavement due to increase in the CBR value of subgrade soil the pavement thickness decreases by 23% from 770mm to 590 mm.

In case of Rigid pavement due to increase in the CBR value of subgrade soil the pavement thickness decreases by 7% from 300mm to 280mm.

In LCCA the cost of Flexible pavement is 46% more compare to rigid pavement for untreated soil.

In LCCA the cost of rigid pavement decreases 26% as compare to flexible pavement for treated soil for treated soil

CONCLUSSION By using small dosage of RBI grade 81, there is substantial increase in the CBR value of subgrades soil and also there will be considerable amount of reduction in pavement thickness, therefore usage of chemical stabilizer, RBI 81 proves to be highly cost effective.

For both the untreated and treated cases the total life cycle cost of rigid pavement is less compared to flexible pavement, so rigid pavement is more economical.

Life cycle cost analysis is more scientific approach for the economic evaluation of alternative design solution and for choosing the best alternative.

REFERENCESIRC: 37-2011(draft), Indian road congress methods of design for flexible pavement “Guidelines for the Design of flexible pavements”. IRC: 58 -2010, Indian road congress “Guidelines for the Design of Rigid pavements”.IS: 2720-Part5 (1980), Indian standard methods of test for soils: Determination of Atterberg Limit, Bureau of Indian Standards, New Delhi.IS: 2720-Part4 (1980), Indian standard methods of test for soils: Determination of Grain Size Analysis, Bureau of Indian Standards, New Delhi. IS: 2720-Part16 (1980), Indian standard methods of test for soils: Determination of CBR values for 4 days soaked soil, Bureau of Indian Standards, New Delhi.

IS: 1498(1970), Indian standard methods of test for soils: Determination of Soil Classification, Bureau of Indian Standards, New Delhi.IS: 2720-Part8 (1970), Indian standard methods of test for soils: Determination Dry density of Soil, Bureau of Indian Standards, New Delhi.Kadiyali L.R, (2011), Highway Engineering, 8 th Edition, Inc. New Yark.Khanna S.K., C.E.G.Justo (1971), Highway Engineering, 9th Edition, Nem Chand & Bros, Civil Lines, Roorkee 247 667 India.Khanna S.K., C.E.G.Justo (1971), Highway material testing, 9th Edition, Nem Chand & Bros, Civil Lines, Roorkee 247 667 India.Steven M.Waalkes, Life Cycle Cost Analysis: A Guide for Comparing Alternate Pavement designs, American Concrete pavement Association, Illinois

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