highway infrastructure projects – conception to …

HIGHWAY INFRASTRUCTURE PROJECTS –

CONCEPTION TO EXECUTION

Prof. A. VEERARAGAVANDepartment of Civil Engineering

Indian Institute of Technology MadrasChennai – 600036.

[email protected]

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NATIONAL HIGHWAYS IN 2001

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NATIONAL HIGHWAYS IN 2001

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“…IT IS NOT WEALTH THAT BUILT THE

ROADS BUT, ROADS THAT BUILT OUR

WEALTH”

- John F. Kennedy

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INDIAN ROAD NETWORK- CURRENT STATUS (km)

National Highway (NH) & Expressways 1,20,543

State Highways (SH) 1,55,222

Other Roads 52,07,044

Total Road Length 54,82,809

* 65% freight & 80 % passenger traffic on roads * Vehicle growth: 10.16% * NHs are less than 2% of network but carry 40% of total traffic

Source: Annual Report, MORTH, 2017

SEQUENCE OF OPERATIONS• Survey investigation and analysis• Report Preparation

• Pre-feasibility Study• Feasibility Study• Detailed Project Report

• Tendering and Award of Work• Construction – Translating design to reality• Operation and Maintenance

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Detailed Project Report (DPR)• Steps:

• Topographic survey • Final location survey • Detailed soil survey • Detailed pavement design • Detailed drainage studies• Environmental studies

• Design report• Drawings • Estimation • Technical approval & Financial sanction • Tendering stage

ISSUES• Soil investigation and characterization• Material availability estimation• Pavement component layer material availability

and characterization• Mix design and characterization – soil/aggregates/

bituminous mixes• Traffic Prediction of each class of vehicle• Pavement Design – Choice of pavement type• Performance prediction• Life cycle cost analysis• Economics of alternate designs• Selection of pavement type for construction

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DESIGN • Types: Flexible, Rigid, Composite• Flexible: 15 Years Design Life, Stage Construction, Standard

Wheel Load, Maintenance as and when needed, Mill andRecycle; Drainage Effect, High Maintenance Cost, High Life CycleCost, Poor Night Visibility, Not Sustainable

• Rigid: Long lasting, Lower LCC, Aggregate Consumption Is Less;Consideration of Spectrum of Axle Loads, Repair is Difficult, Skidrelated issues, Longer Curing Time, Utility Cuts

• Composite: Suitable for medium traffic level; Long lasting andsustainable, low LCC

• Design Factors: Soil Characteristics, Pavement ComponentMaterials characterization, Mix Design, Wheel Loads, SubgradeSoil, Climatic Factors, Drainage and Environmental Factors

• Pavement Type Selection and Thickness Design11

Traffic Growth • Normal Traffic• Generated Traffic

• Diverted Traffic• Induced Traffic

• Developmental Traffico Traffic Prediction

• AADT from ADT and Seasonal Variation• Prediction of Traffic Growth rates for each

class of vehicle• ARIMA model

TRAFFIC GROWTH

State ModeFY 09-10

FY 10

- 11

FY 11 –12

FY 12 -13

FY 13-14

FY 14-15

FY 15-16

FY 16-17

FY 17-18

Tamil Nadu 2A 13% 1% -3% 0% 13% 10% -10% -9% -5%MAV 13% 8% 3% 3% -5% 29% -2% 5% -4%

A.P 2A -6% -8% -10% -7% -10% 5% 21% 7%MAV 11% 11% -1% 0% 9% 13% 13% -2%

Gujarat 2A -27% -24% -17% -9% -11% 11% -21%MAV 3% 9% -1% 6% 7% 16% 4%

Karnataka 2A -10% -14% 31% -14% 7%MAV 3% -14% 3% 28% -3%

Rajasthan2A -13% 12% 17%3A -18% -16% -2%

MAV 5% 4% 6%

Note: Other than Rajasthan Project, there is no split up between 3A & MAV's. 13

CONSEQUENCE OF INADEQUATE TIME FOR PROJECT PREPARATION, POOR DESIGN AND

POOR QUALITY OF CONSTRUCTION –PRE-MATURE DISTRESSES

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WHAT WENT WRONG?• CBR of the subgrade soil of the constructed pavement

did not match with the design CBR• Compaction of subgrade - lower than the design

requirements• Gradation of Granular Sub-Base - did not meet the

drainage requirements• Compaction of granular layers - lower than the

requirements• Binder quality, mix design requirements, compaction

level of the layers and the choice of the pavementlayers - not as per best practicesCan we get desired the performance from a design based on lab tested / assumed material properties?

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IMPORTANCE OF RELATING QUALITY OF CONSTRUCTION TO

PERFORMANCE

• How reliable are lab. material test results adopted inpavement design to predict desired performance ofpavements under actual traffic, climate andenvironmental conditions?

• How are the lab. material test results related to field testresults?

• Are they very different? If so, what is their influence ondesign thickness and the predicted performance?

• Can the variability in construction quality be quantifiedand controlled?

• What are their levels of influence on performance?

IMPORTANCE OF RELATING QUALITY TO PERFORMANCE

• How to account the construction quality variability in thedesign process?

• What is the relation between the variability inconstruction quality and the expected “uniform”pavement life/performance?

• What construction parameters are to be consideredduring inspection in order to reduce pavement lifevariance and increased reliability?

• How should the construction practices be improvedthrough process control to ensure desired/predictedlife/performance?

FUNDAMENTAL QUESTIONS• What do we want ? – Materials of needed strength, thickness of

layers as per design/code, stresses and strains within allowablelimit? or Performance - rut/crack/deflection/ roughness etc., withinallowable limits; Or both?

• How do you order? Materials with expected properties and designthickness through MEPDG analysis to ensure satisfactoryperformance

• How do you know, what you get (thickness from design) is whatyou wanted (to ensure satisfactory performance)?

• Sample Size and Tests: How many samples are to be tested?What are the significant QC/QA tests that will ensure “good” qualityconstruction? Which tests significantly ensure satisfactoryperformance?

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WHAT DO YOU WANT?• Strength / Modulus • Tensile Strain at the

bottom of bituminous layers within allow. limits

• Durability • Compressive strain on top of subgrade within allow. limits

• Voids • Tensile strain at the bottom of stabilized layer within allow. limits

• Thickness • Cracking < 20%

• Deflection • Rutting < 20 mm24

HOW DO WE ORDER?

• Materials that will ensure min. modulus values• Min. thicknesses that will ensure limits of

stresses and strains• Limits of temperature range / moisture range/

traffic levels?• Contract: Method or recipe / End result /

Quality assurance / warranty/ performancebased specifications/proprietary product

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Asphalt

Base

Subgrade

ConstructionParameters

Material Models PavementPerformance

RELATION BETWEEN AS-BUILT QUALITY AND PAVEMENT PERFORMANCE

As-BuiltQuality

PavementPerformance?

“Process”

Fatigue Cracking& Rutting

Layer Moduli

ConstructionParameters

compaction,moisture content& dry density

Construction

PROCESS

Asphalt Content,Compaction,Dry Density,

Moisture Content

Agg. passing 4.75 mmAgg. passing 0.6 mmAgg. Passing 0.3 mmAgg. Passing 0.075 mm

• Fatigue Cracking

• Subgrade Rutting

• AC Rutting• AASHTO

Failure Criterion

Example: Witczak Model for Asphalt Layer

Modulus is a function of:

air voids,asphalt content, agg. passing

0.075 mm,asphaltviscosity,etc…

Construction

Modulus & Thickness of Each Layer

RegressionEquations

Cons

truc

tion

Proc

ess

Cont

rol

Design&Analysis

t2,

t1,

t3,

E1

E3

Pavement Parameters

E2

t2,

t1,

t3,

E1

E3

Pavement Parameters

E2

Analysis

Analysis+2σ

+σ-σ-2σ

µ, COV

PavementPerformance

“Rational” Estimationof Performance( mean, COV )

Main Idea

PavementPerformance

Single Value

Asphalt Content Temperatureetc...etc...

Impact of Construction Parameterson Performance

10%

12%5% 6%

48%

21%P200 Percent Air VoidsViscosity Percent asphalt contentDry density of base Specific gravity of subgrade

PavementPerformance

Time

Thickness of Asphalt Modulus of Asphaltetc...

ConstructionDesignMix

etc...

METHODOLOGY

33%

28%

2%1%

3%

10%1%

3%

8%

7%

4%

OMC MDD COM MCSat SH SW PClayPSilt P40 CBR

33%

28%

2%1%

3%

10%1%

3%

8%

7%

4%


OMCOMC MDD COM MCSat SH SW PClayPSilt P40 CBR

33%

28%

2%1%

3%

10%1%

3%

8%

7%

4%


33%

28%

2%1%

3%

10%1%

3%

8%

7%

4%


OMCOMC MDD COM MCSat SH SW PClayPSilt P40 CBR

Structural Impact Chart

Material Impact Chart

IMPACT CHART

1%

23%

28%14%

29% 5%Thickness of AC Thickness of Base Thickness of SubgradeModulus of AC Modulus of Base Modulus of Subgrade

• Construction translates design recommendationinto reality

• Construction quality - influences performance• How to define construction quality? What tests

define construction quality?• Can we develop pay factors based on quality of

construction? If yes, how?• Need to link construction quality to performance

and in performance prediction models tounderstand the rate of deterioration and plan theschedule for maintenance

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• Issue: Assume material properties and consequent design forthe desired performance vis-a-vis actual material propertythrough NDT tests based on quality of construction & resultantperformance

• Lab test results are far away from reality

• Lab test results / APTFs do not simulate actual traffic, climateand environmental conditions and also the actual constructionquality

• Field performance is the key as it considers in-situconstruction quality, actual traffic load repetitions under actualclimatic conditions;

• Need of the hour is to collect periodic performance data,through sponsored research and relate theory to practice.

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SUMMARY• Researchers should relook at their lab. tests on pavement

materials prepared under ideal conditions and expecting thepavement to be constructed under similar conditions in thefield

• Lab performance tests on individual materials prepared atconstant density and voids, tested under constant load,frequency of testing, rest period, temperature, moisture etc.,may not be relevant to predict the field performance of thepavement system under actual traffic, climate,environmental conditions with variation in constructionquality

• Researchers expect the performance of the pavementsystem as they understand, but the pavement system doesnot understand their complicated models and equations.

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SUMMARY• Prediction of the performance of the pavement

system from limited lab tests on individualmaterials in isolation will be misleading

• Field samples to be tested in the lab to understandthe effect of variability in construction quality on thetest results and relate to field performance

• Field performance data and Non-Destructive Testsin the field to understand the effect of constructionquality on material characteristics, is the need ofthe hour.

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ACNOWLEDGEMENTS

• Prof. Soheil Nazarian, UTEP, El Paso• Col. Deepak Baskandi, Indian Army

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THANK YOU…

highway infrastructure projects – conception to …

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