Indian Highways Vol.41 5 May 13

8/19/2019 Indian Highways Vol.41 5 May 13

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The Indian Roads Congress

E-mail: [email protected]/[email protected]

Founded : December 1934

IRC Website: www.irc.org.inJamnagar House, Shahjahan Road,

New Delhi - 110 011

Tel : Secretary General: +91 (11) 2338 6486

Sectt. : (11) 2338 5395, 2338 7140, 2338 4543, 2338 6274

Fax : +91 (11) 2338 1649

Kama Koti Marg, Sector 6, R.K. Puram

New Delhi - 110 022

Tel : Secretary General : +91 (11) 2618 5303

Sectt. : (11) 2618 5273, 2617 1548, 2671 6778,

2618 5315, 2618 5319, Fax : +91 (11) 2618 3669

No part of this publication may be reproduced by any means without prior written permission from the Secretary General, IRC.

Edited and Published by Shri Vishnu Shankar Prasad on behalf of the Indian Roads Congress (IRC), New Delhi. The responsibility of the

contents and the opinions expressed in Indian Highways is exclusively of the author/s concerned. IRC and the Editor disclaim responsibility

and liability for any statement or opinion, originality of contents and of any copyright violations by the authors. The opinions expressed in the

papers and contents published in the Indian Highways do not necessarily represent the views of the Editor or IRC.

VOLUME 41 NUMBER 5 MAY 2013

CONTENTS ISSN 0376-7256

LIST OF ADVERTISERS

ICT Pvt. Ltd. - Inside Front Cover

AE&C - Inside Back Cover

Bentley Systems Pvt. Ltd. - Outside Back Cover

10 Metal Engineering & Treatment Co. Pvt. Ltd.

11 Rettenmaier India Pvt. Ltd.

12 BASF

13 Tiki Tar Industries India Ltd.

14 Alchemist Touchnology Ltd.

15 IRF-India Chapter

16 Advertisement Tarrif

23 Primax Equipment Pvt. Ltd.

24 Gloster Limited

39 Casta Engineers Pvt. Ltd.

40 Poly Flex

65 Perma Construction Aids Pvt. Ltd.

65 Arun Soil Lab Pvt. Ltd.

66 Coir Board

75 Redecon (India) Pvt. Ltd.

92 Alexis Enterprises Pvt. Ltd.

93 Techfab India

94 Halcrow Consulting India Pvt. Ltd.

95 Jalnidhi Bitumen Specialities Pvt. Ltd.

96 New/Revised Publications Now Available on Sale

INDIAN HIGHWAYSA REVIEW OF ROAD AND ROAD TRANSPORT DEVELOPMENT

Page

2-3 From the Editor’s Desk

4-9 Glimpses of First Collaborative Endeavour of IRC with

Educational Institutions

17 Inuence of Environmental Factors on TemperatureDifferential in High Performance Cement Concrete

Pavements

K.S. Suresh Kumar, M.S. Amarnath and G.B. Avinash

25 Quality Audit for Concrete Constructions

C.V. Kand

41 Sustainability Challenges & Opportunities in Bridge

Building

V. N. Heggade

57 Inuence of Skew Angle in the Design of Grids Madhavi N, Baskar K, Natarajan C and Rajaraman A.R.

67 Experiences from Investigation of Expansion Joints and

Bearings in Concrete Bridges

S.K. Sharma, Lakshmy Parameswaran, Rajeev Goel and

Sushil Kumar

76-88 Amendments to IRC:6-2010 and IRC:78-2000

89-90 Circulars Issued by MORT&H

91 Tender Notice of NHs Kanpur


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2 INDIAN HIGHWAYS, MAY 2013

Dear Readers,

The visionary decision taken by the Government for getting highway projects executed through

Engineering Procurement and Construction (EPC) mode in place of traditional mode of item rate

contracts may provide the much needed relief to the road sector players. In the current scenario of

global economic downtrend with symptoms of economic contraction, the execution of highway sector

projects through EPC mode may allow much needed breather both to the Contractors & Financers, as

EPC contracts are public funding cash contracts. This may also allow much needed consolidation in the

sector which may help in strengthening the foundation for achieving greater pace of progressiveness

in the coming years.

As normally happens, the introduction of new system/mode comes with some apprehensions and

reservations among the different stakeholders. There is a need to demystify the EPC benets, processand procedures. This may require a concerted efforts as well as collaborative approach from all the

stakeholders. However, the visionary action of the government of introducing EPC in highway sector

is clearly a step towards building a climate perceivable to be friendly to enterprises, investment and

expeditious development in the road building activities which will have enormous positive linkages to

the overall economic development.

The EPC mode provides an opportunity as well as exibility to the Contractor(s) to introduce cuttingedge technologies, techniques, instrumentation, new materials, etc. This may help him in not only in

improving the efciency but may also help in improving overall durability as well as bringing downthe cost of the project(s).

The EPC entrepreneur(s) may also have the scope to make use of emerging concept of “frugal”

engineering which implies lean engineering methodology or process that involves optimum use of

resource(s) at hand.

Similarly, the various approvals/permissions to be provided by the client road authorities within the

stipulated time frame augurs well for all stakeholders including public, as system of implementation of

projects becomes a well-dened and transparent process. However, this may result in added pressureon the cliental road authorities to meet the stipulated deadlines for different activities especially related

to handing over the land, environmental clearances, General Arrangement Drawings (GAD), etc. There

may be some possibilities of augmenting the human resource in certain domain areas of the cliental

road authorities coupled with upgrading the skill of existing manpower.

From the Editor’s Desk

EPC IN HIGHWAY – WIN-WIN FOR ALL


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EDITORIAL

INDIAN HIGHWAYS, MAY 2013 3

The explicit provision of damages payable to the Contractors on account of non-availability of the

stipulated clearances, etc. clearly reects towards the transformation of role of the government –moving away from the command and control economy/development of earlier days towards ensuring

good governance and an effective system to incentivize innovation(s) and removal of inefciency. Thisis also reected in provisions related to payment of bonus for early completion of the project(s).

The EPC mode in highway sector also throws open more opportunities for job creation and

employment in the road sector including entrepreneurship in the domain areas of consultancy services

in project preparation, survey & investigations, road safety, quality control, etc. This is adequately

reected in the enabling provision of 70% of work which can be outsourced by the EPC Contractor.Possibly EPC may prove to be a game changer in road sector in the coming years.

Perceptible benets of the EPC in road sector may be many but of course best practices suitingdifferent category of projects needs to be evolved, which may get evolved over a time period and

feedback based there on from different implementing agencies. In the process of transition to new

concepts and systems, it is always preferable to remember the wise words of Osho:- “Knowledge

makes you learned, but wisdom makes you innocent. Knowledge is ego fullling but wisdom kills ego.Wisdom is simply wisdom. It is truth. Wisdom cannot be true or untrue”.

Place: New Delhi Vishnu Shankar Prasad

Dated: 22nd April, 2013 Secretary General

—————


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HIGHLIGHTS


As a new initiative of widening the reach of IRC,

a collaborative approach with technical institutions

has been initiated by IRC. In the rst of the series,a National Event “Transport Infrastructure Congress

and Expo-2013 (TICE-2013)” has been organized as

joint endeavour by the Malaviya National Institute

of Technology (MNIT) Jaipur & IRC from March 7,

2013 to March 9, 2013 as a part of Golden Jubilee

Celebrations of MNIT Jaipur.

The event generated a lot of interest from all the

stakeholders including the private sector and

particularly the student community of the

engineering colleges. It is heartening to

mention that 25 Engineering Colleges/Universities participated in this event from the States of

Rajasthan, Gujarat, Uttar Pradesh, Orissa,

Karnataka & Tamil Nadu. Besides students and

faculties of these colleges, a large number of

professionals/engineers/scientists from the

Central Government, State Government,

Public Sector Units, Research Institutions, etc.

participated in the deliberations. The

engineering students for the rst time were given a

unique opportunity of having interaction with the practising professionals & experts in the eld of

GLIMPSES OF FIRST COLLABORATIVE ENDEAVOUR OF

IRC WITH EDUCATIONAL INSTITUTIONS

road & road transport sector. The students were

exposed to the wisdom of the experts, thereby

preparing them to meet the challenges in future in

better way. The engineering students showcased

their talent and capabilities through the working

models and posters on the real life issues in the

road and road transport sector.

The major features of the event were:-

1. Two day National Workshop/ Conference.

2. Three day Technical Exhibition on

Transportation technologies and materials.

3. Student Research Model Exhibition/

Competition.4. Three days Career Counselling Session

over job opportunities in Transport Sector/

Engineering.

The State Government of Rajasthan extended full

support to the event. Shri Shanti Dhaliwal, Hon’ble

Minister of Urban Development, Government of

Rajasthan inaugurated the event. The inaugural event

was also attended by Shri Gajendra Haldea, Advisor

to DCH (Infrastructure) Planning Commission, Govt.

of India as Guest of Honour besides other dignitariesfrom the Central and State Government.

Glimpses of Inaugural Session

Shri Shanti Dahliwal, Hon’ble Minister Urban Development, Govt. of Rajasthan


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HIGHLIGHTS


Shri Gajendra Haldea, Advisor to DCH (Infrastructure)

Planning Commission

Shri G.S. Sandhu, Additional Chief Secretary,

Government of Rajasthan

View of Audience

During the event the Experts/Speakers made presentation on the following topics.

1. “Design of Noise Barrier for Elevated Highway

Infrastructure” by M. Parida, Professor IIT

Roorkee.

2. “Transit Oriented Sustainable Urban

Development” by S.L. Dhingra, Professor IIT

Bombay.

3. “Road Drainage A case Study of Panipat City” by S.N. Sachdeva, Professor NIT Kurukshetra

4. “Enabling New Policy Initiatives of MoRTH

to Promote Innovation and Road Safety” by

S.K. Nirmal, MoRTH, New Delhi

5. “New Materials & Technology in Roads” by

P.K. Jain, Head Flexible, Pavement Division,

CRRI


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HIGHLIGHTS


6. “Review of Bituminous Mixes Used in India”

by Prof. P.S. Kandhal, Associate Director

Emeritus, National Center for Asphalt

Technology, USA

7. “Remote Sensing & GIS application for RouteAlignment ” by P K Garg, Professor IIT

Roorkee

8. “Trafc Infrastructure Projects for Jaipur city” by Shri Kuldeep Ranka, Jaipur Development

Commissioner

A Panel Discussion was also held. The students/researchers were given an exclusive opportunityto have rst-hand interaction with the expertsof various issues relating to the road transport

sector. The Panelist were Shri Vishnu ShankarPrasad, Secretary General, IRC, Professor P.S.Kandhal, M Parida, Prof. IIT Roorkee, S L Dh-ingra, Prof. IIT Bombay, Dr. I.K. Bhatt, DirectorMNIT Jaipur, Prof B L Swami MNIT Jaipur andDr. Arun Gaur MNIT Jaipur.The innovative feature of this event was the exhibition of research models/posters on the theme oftransport infrastructure by the students. The stu-dent showcased the solutions to various problemsand current issues & situations in the road sec-tor. Prizes were distributed to encourage students.The models & posters were evaluated by a groupof experts under categories namely (i) Electronics(ii) Architecture (iii) Civil & (iv) Posters. Thewinners under four categories were as under:-

1. Electronics Category

(i) Shri Akhil Jain, 3rd Year B.Tech

Electronics & Communication

Engineering, MNIT Jaipur on an

embedded system which is used for

tracking and positioning of any vehicle by

using Global Positioning System (GPS) &

GSM.

(ii) Team of S/Shri Utkarsh Verma, Shayam

Sunder, Vipin Kumar Choube & Saurabh

Jain (VII SEM, VIT-EAST, ECT) on

Multi Storeyed Automatic Parking;

(iii) Team of S/Shri Gaurav Upadhyay

& Hitendra Singh Rathore, 3rd Year

B.Tech (Electrical Enginnering),

Poornima Institute of Engineering &

Technology, Jaipur (PIET) on sendingtimely information to the train drivers

regarding signals, boards and approaching

trains.

2. Architecture Category

(i) Team of Shri Kamal Tahilramani,

Shri Prateek Parashar, Shri Deepak

Kumar, Shri Samarth Patel, Ms Umang

Jain & Shri Tushar Sharma (Ayojan

School of Architecture) on Elevated

Road Over The Tonk Road, Jaipur with

a underpass crossing on B2 Bypass and

Provision of Suspended Monorail.

(ii) Team of S/Shri Saptarshi Kapri, Mitesh

Jatolia, Preet Kanwar Singh, Kartik

Paturkar & Vipul Raj (Ayojan School of

Architecture) on Metro Station Design.

3. Civil Engineering

(i) Team of S/Shri Mukesh A. Patel (Ganpat

University, Meshana, Gujarat) ShriGautam Dadhich (PDPU, Gandhinagar,

Gujarat) & Dr. H.S. Patel (LDCE,

Ahmedabad) on Modied Dynamic ConePenetrometer (DCPM) and Modied StateCone Penetrometer (SCPM).

4. Poster

(i) Team of Mukesh A. Patel (Ganpat

University, Meshana, Gujarat), Gautam

Dadhich (PDPU, Gandhinagar, Gujarat &

Dr. Rakesh Kumar (Associate Professor,

SVNIT, Surat.

The list of the educational institutions which

participated in the event organized at MNIT

Jaipur is as under:-

• Arya College of Engg. & Research Center,

Jaipur


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HIGHLIGHTS


• Aayojan School of Architecture, Jaipur

• Amity School of Engineering and Technology

• Baldev Ram Mirdha Institute of Technology,

Jaipur • CBS Group of College

• Ganpat University, Meshana, Gujarat

• Global Institute of Technology, Jaipur

• Government Engineering College, Jhalawar

• Gyan Vihar University, Jaipur

• IIT Roorkee

• Jaipur Institute of Technology, Group of

Institutions, Jaipur

• JECRC, Jaipur

• Kautilya Institute of Technology &

Engineering, Sitapura, Jaipur

• L. D. College of Engineering, Ahemdabad

• NIET (NIMS University), Jaipur

• P. I. E. T. Jaipur

• Pandit Deendayal Petroleum University,

Gandhinagar, Gujarat

•

PEC University of Technology• Poornima Group of Institutions, Jaipur

• Poornima Institute of Engineer and

Technology, Jaipur

• Sri Balaji College of Engg. & Tech., Jaipur

• Sri Shakti Institute of Engineering and

Technology

• BMS College of Engineering, Bangalore

•

Orissa College of Engineering, Bhubaneswar • NIT, Surat

The new materials/equipment/instruments

accredited by IRC were also displayed in the

Technical Exhibition. It helped the students

to get an exposure of the emerging materials/

technology/techniques in the road sector.

Glimpses of Prize Distribution & Winning Models

Winner Civil Category (Modied Cone Penetrometer (DCPM) and Modied Static Cone Penetrometer (SCPM)


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HIGHLIGHTS


Architecture Category (Elevated Road) Winner (Joint) Electronics Category (Timely information given

to train driver regarding signals, board and approaching trains)

Winner Electronics Category (Tracking and Positioning of any vehicle by using GPS & GSM)


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HIGHLIGHTS


W i n n e r ( J o i n t ) E l e c t r o n i c s C a t e g o r y

( M u

l t i S t o r e y e d A u t o m a t i c P a r k i n g S y s t e m )

P r i z e D i s t r i b u t i o n b y S e c r e t a r y G e n e r a l ,

I R C

& D i r e c t o r M N I T , J a i p u r

W i n n e r o f A

r c h i t e c t u r e C a t e g o r y ( M e t r o S t a t i o n D e s i g n )

W i n n e r o f P o s t e r C a t e g o r y ( M i c r o s u r f a c i n g : A n I n n o v a t i v e

T e c h n o l o g y f o r P

a v e m e n t P r e v e n t i v e M a i n t e n a n c e )


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TECHNICAL PAPERS


ABSTRACT

Daily and seasonal variations in temperature and moisture

are important factors inuencing the functioning of concrete pavements. In addition to temperature, other environmental

factors that affect rigid pavement performance include humidity,

precipitation, amount of solar radiation etc. This paper is part of

a comprehensive study on High Performance Cement Concrete

Pavements (HPCCPs) conducted at Bangalore University.

Amongst the HPCs, an approach is made in this paper to

determine the realistic temperature differential in High Volume

Fly Ash Concrete (HVFAC). Durability tests such as abrasion,

water absorption and exural fatigue were conducted on HVFAC

in addition to compressive and static exural strength tests. Thetest results show that the HVFAC is a high performance concrete.A HVFAC concrete slab is instrumented with thermocouples, for

monitoring temperature at three regions, interior, edge and corner.

Thermocouples are inserted at top, middle and bottom of the slab.

The variation in pavement temperature is recorded every hour for

seven days. The inuence of climatic conditions such as humidityand number of solar radiation hours on daily and seasonal variations

(summer, winter and monsoon) of temperature differential through

the slab thickness is investigated. The minimum top temperatures

during summer, winter and monsoon seasons were 22.8˚C, 21.30ºCand 21.10ºC respectively. The maximum top temperatures duringsummer, winter and monsoon seasons were 53.9ºC, 42.30ºC and38.60ºC respectively. The maximum temperature differentials

observed during summer, winter and monsoon season were 13.5ºC,13ºC and 8.80ºC respectively. Taking into account the localenvironmental factors and the material properties, temperature

differential prediction models for HVFAC slabs are suggested

in this paper. The temperature differential at any location in

India can be obtained by developing similar prediction models

and substituting values of the environmental parameters in the

prediction models. The values of these parameters are available

from Indian Meteorological Department. Temperature stresses are

evaluated by using the classic Westergaard equations.

1 INTRODUCTION

Temperature is an important factor inuencingthe performance of cement concrete pavements.

The temperature differential is a function of the

heat transfer mechanisms of thermal conduction,

convection and solar radiation. Liu Wei 2005 reports

that environmental factors like humidity, wind,

precipitation, frost etc. also cause variations in

temperature. The cement concrete pavement response

to temperature differences through the slab thickness

is recognized as curling. A positive temperature

difference between the top and bottom surfaces of the

concrete slab during day time causes the slab corners

to curl downwards, while a negative temperature

difference during night time results in upward

curling of slab corners. Since concrete can recover

its original shape after the effects of temperature

variation are removed, the curling due to temperature

variation from daily or seasonal weather condition

can be considered as a transient component of slab

curvature behavior due to environmental loading.

Curling induces stresses in the pavement, since the

pavement is restrained by its weight. The thermally

induced stress caused by such interaction may result

in early pavement cracking. At present, in India

IRC:58 “Guidelines for the Design of Plain Jointed

Rigid Pavements for Highways,” is used for design

of cement concrete pavements. IRC:58 suggests

temperature differential values for different zones in

India to evaluate temperature stresses.

Mechanistic-empirical design is a method of

designing highway pavements. It combines empirical

relationships obtained from the eld data withtheoretical predictions based on the mechanics of

materials. This method relates inputs such as trafc,

loadings, soil strength, climate, etc. to the actual pavement response. Mechanistic-empirical method

* Research Scholar, Department of Civil Engineering, Bangalore University, Bangalore, E-mail: [email protected].

** Professor in Highway Engineering, Bangalore University, Bangalore, E-mail: [email protected].

*** Assistant Engineer, Water Resources Department, KPWD, Belgaum

INFLUENCE OF ENVIRONMENTAL FACTORS ON

TEMPERATURE DIFFERENTIAL IN HIGH PERFORMANCE

CEMENT CONCRETE PAVEMENTS

K.S. SURESH K UMAR *, M.S.AMARNATH** AND G.B. AVINASH***


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TECHNICAL PAPERS


is more accurate than empirical method because the

empirical method only relies on the eld performance,while the Mechanistic-empirical method combines

both eld performance and theoretical prediction

models. A Mechanistic – Empirical design approach ismade in this study by considering the environmentalfactors, solar radiation and humidity in addition to

air temperature to determine the realistic temperature

differentials in HVFAC.

2 EXPERIMENTAL INVESTIGATIONS

The present study is part of a comprehensive study

on High Performance Cement Concrete Pavements

(HPCCPs) conducted at Bangalore University.

Amongst the HPCs an approach is made in this paper

to determine the realistic temperature differential inHigh Volume Fly Ash Concrete (HVFAC) only. An

existing HVFAC pavement slab free from vehicular

movement is identied for conducting temperaturestudies. The study area is located in the southern part

of India at Bangalore City, Karnataka, geographically

located at latitude 12º 95`N and longitude 77˚54̀ E. Dimensions of the HVFAC pavement slab are

4400 mm x 3300 mm and thickness 300 mm. The

shoulders have a minimum CBR value of 10% andcompacted with vibratory roller at OMC to achieve

density of 97% MDD. M40 Grade concrete havingmix proportions 1:1.22:1.78 consisting of Binder50:50 (53 Grade cement conrming to IS12269:1987and Fly Ash- Pulverized Fuel Ash conrming toIS3812:2003), water binder ratio 0.38 is used to

cast the slab. To determine the compressive strength

of HVFAC pavement under study, cylindrical core

samples were taken two years after the pavement

was laid. The cylindrical compressive strength was

44.35MPa. The equivalent cube compressive strength

(calculated as per IS: 516-1999 Clause 5.6.1) was

55.44MPa.

3 SLAB INSTRUMENTATION

To record the temperature at different depths of the

concrete slab temperature sensors called thermocouples

are used. A thermocouple is a sensor for measuring

temperature. It consists of two dissimilar metals,

joined together at one end, which produces a small

unique voltage at a given temperature. This voltage is

measured, converted and displayed by an electronic

digital temperature indicator directly as temperature

in degree Celsius. In this study K–type thermocoupleand a temperature indicator capable of measuring

0.1ºC with a range of -10.0ºC to 100.0ºC is used.20 mm diameter holes are drilled at interior, edge andcorner region of the slab. Thermocouples are xed toa wooden bead 16 mm square and 300 mm long such

that the tips of the thermocouples are exactly 25 mm,

150 mm and 275 mm from top of the slab as shown in

Plate 1. The wooden beads are inserted into the hole

and the space around it is grouted using cement slurry.

Fig.1 shows a typical schematic representation of slab

instrumentation.

Plate 1 Thermocouples Fixed to Wooden Bead and

Data Recording

Fig.1 Schematic Representation of Slab Instrumentation

A = 275 mm, B = 150 mm, C = 25 mm,

T = Tip of the Thermocouple

4 DATA ACQUISITION

Each thermocouple has two leads. The leads

are connected to a digital temperature indicator

which directly shows temperature at the tip of the

thermocouple in degree Celsius. Plate 1 shows


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TECHNICAL PAPERS


thermocouples xed to wooden bead at three levelsand digital temperature indicator connected to leads

for recording temperature. Temperatures at top,

middle and bottom of the slab and air temperature at

about 300 mm from slab top are recorded every hourfor seven days during each season. The temperature

data are manually recorded. Environmental data such

as solar radiation hours and humidity are taken from

the Indian Meteorological Department for Bangalore

region.

5 MONITORING RESULTS AND DATA

ANALYSIS

Pavement top temperatures ranged from 45ºC to52ºC during summer season (last week of April)

and the average air temperature was 34ºC. Duringwinter season (last week of December) pavement

top temperatures ranged from 22ºC to 36ºC and theair temperature ranged from 20ºC to 36ºC. During

monsoon season (last week of June) pavement top

temperatures ranged from 31ºC to 39ºC and the airtemperature ranged from 29ºC to 34ºC. The hourlyvariation of temperature at top, middle and bottom

in the corner region for monsoon season is shown inFig.2.

The temperature of slab is more at the top during day

time and more at the bottom during night time. This is

because the top of the slab is exposed to direct solar

radiation. Variation of temperature at top of slab is

more than that at bottom. This could be due to loss

of heat during transmission. Variation of temperature

is more at edge region than at corner region. This is

due to more loss of heat at edge region as the slab is

in contact with the shoulder. Maximum and minimumtemperatures and day time and night time temperature

differential for summer, winter and monsoon seasons

in HVFAC slab are shown in Table 1.

Fig.2 Hourly Variation of Temperature in HVFAC Slab

Table 1 Temperature and Temperature Differential in HVFAC Pavements

Summer season Winter season Monsoon season

Data Position I E C I E C I E C

Min.

Temp.

T 28.90 28.80 28.40 19.50 22.30 19.60 22.80 21.10 24.20

B 30.10 29.90 29.40 - 18.60 23.60 24.30 20.10 25.60

Max.

Temp.

T 53.90 52.00 51.80 42.30 39.20 37.70 33.90 33.00 38.60

B 49.80 44.30 50.40 - 32.00 31.10 33.80 29.70 34.80

T Diff Night -8.00 -6.80 -8.00 - -6.10 -6.00 -8.80 -6.10 -8.30

T Diff Day 11.40 13.50 13.40 - 13.00 10.30 5.20 5.90 5.00

I is the Interior region, E the edge region and C the corner region. T is top and B is bottom of slab.


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Note :

1. The temperature differentials in the slab refer to the

difference between the top and bottom temperature.

2. Temperature at bottom of slab in the Interior region is

not recorded due to malfunctioning of thermocouple.

It is observed that the day time temperature differential

in the edge region is more than that at interior and

corner regions where as the night time temperature

differential is more in interior region. There is not

much difference between average air temperature

during winter and monsoon season. From Table 1 it

is seen that the temperature differentials are positive

during day time and negative during night time,

Negative night time temperature differential values

are less signicant than positive day time temperaturedifferentials and negative differentials occur much less

often than positive differentials this can be attributed

to the presence of solar radiation during day time.

The pavement top temperature and the temperature

differential are lower during monsoon than winter.

This could be due to precipitation and the presence

of clouds during monsoon thus causing lesser solar

radiation.

6 DEVELOPMENT OF PREDICTION

MODEL FOR TEMPERATURE

DIFFERENTIAL IN HVFAC SLAB

A statistical model is attempted to predict the

temperature differential as a function of pavement top

temperature and depth of the slab. As the pavement

temperature depends on environmental factors it is

desirable to rst develop a model for pavement toptemperature which is dependant on air temperature,

humidity and accumulated solar radiation. For datacorrelation, it is necessary to dene the following;

a) Solar Radiation Hours (SRH): This is denedas the number of hours elapsed from sunrise

to the time peak pavement top temperature is

reached.

b) Percent Humidity (H): It is the humidity at the

peak period.

c) Average daily air temperature (AAIRT): The

average of daily air temperature that occurs

between 9 a.m. to 2 p.m.

6.1 Pavement Top Temperature PredictionModel

The pavement top temperature prediction models are

described by the following equations:

Winter pavement top temperature prediction

model

TTOP=16.25+0.21*AAIRT+1.91*SRH+0.01*H (1)

(n = 7, R 2 = 0.92)

Summer pavement top temperature prediction

model

TTOP=51.51+1.11AAIRT-4.88SRH+0.14*H (2)

(n = 7, R 2 = 0.75)

Monsoon pavement top temperature prediction

model

TTOP=16.69+0.42*AAIRT+1.53*SRH–0.41*H (3)

(n = 7, R 2 = 0.76)

Combined pavement top temperature prediction

model (summer, winter and monsoon season)

TTOP=32.18–0.03*AAIRT+1.48*SRH–0.15*H (4)

(n = 14, R 2 = 0.73)

Where; TTOP is the maximum pavement top

temperature and AAIRT is the average air temperature

in degree Celsius, SRH is the solar radiation period in

hours and H = Humidity in percent.

6.2 Temperature Differential Prediction Model

The prediction models for positive day time

temperature differentials are developed using the

pavement top temperature developed from equations

(1) to (4) and depth of the slab as variables.

ΔT+ = -27.87 + 0.68*TTOP + 0.04*D (5)

Where; ΔT is the positive day time temperaturedifferential in degree Celsius, TTOP is the pavement


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top temperature in degree Celsius and D is the

thickness of the concrete slab.

The maximum temperature differentials actually

recorded during each season are shown in Table 2. The

temperature differentials arrived at using temperature

differential prediction models are shown in

Table 3. The comparison between actual and predicted

temperature differentials during winter season at

edge region is shown in Fig.3. Table 4 shows the

comparison between actual and predicted temperaturestresses.

Table 2 Actual Temperature Differentials Recorded During Each Season

SUMMER SEASON WINTER SEASON MONSOON SEASON

Day I E C I E C I E C

1 4.9 8.8 8.5 - 11.4 9 5.2 5.9 4.2

2 4.9 8.8 8.5 - 13 8.93 3.2 3.3 2.4

3 1.1 6.6 7.6 - 10.4 10.3 2.5 3.1 2.3

4 4.7 8.6 8.3 - 10.2 8.8 0.8 2.8 1.4

5 1.7 7.1 8 - 8.8 9 3.2 2.7 1

6 4.7 8.6 8.3 - 11.3 8.8 3.2 5.2 3.5

7 4.7 8.6 8.3 - 10.6 6.6 5.1 3.1 4.7

Table 3 Temperature Differentials Arrived at Using Prediction Models



1 4.52 7.36 7.44 - 12.38 12.46 7.99 9.8 4.71

2 4.06 7.28 7.56 - 13.82 12.11 6.33 9.3 3.74

3 4.01 7.25 7.57 - 12.62 12.83 7.11 8.25 3.524 4.54 7.36 7.47 - 10.77 11.75 3.8 7.23 2.05

5 3.65 7.16 7.69 - 10.98 11.05 7.13 6.82 2.54

6 3.97 7.23 7.57 - 12.13 11.68 6.83 8.39 3.18

7 4.11 7.25 7.56 - 11.04 10.92 7.79 8.43 3.34

Fig.3 Comparison Between Actual and Predicted Temperature Differentials


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Table 4 Comparison Between Actual and Predicted Temperature Stresses


ACTUAL

TEMPERATURE

STRESSES


1. 0.51 0.82 0.41 - 1.06 0.43 0.54 0.55 0.202. 0.51 0.82 0.41 - 1.21 0.43 0.33 0.31 0.11

3. 0.12 0.61 0.36 - 0.97 0.49 0.26 0.29 0.11

4. 0.49 0.80 0.40 - 0.95 0.42 0.08 0.26 0.07

5. 0.18 0.66 0.38 - 0.82 0.43 0.33 0.25 0.05

6. 0.49 0.80 0.40 - 1.05 0.42 0.33 0.48 0.17

7. 0.49 0.80 0.40 - 0.99 0.32 0.53 0.29 0.22

1. 0.47 0.68 0.36 - 1.15 0.60 0.84 0.91 0.22

CALCULATEDTEMPERATURE

STRESSES

2. 0.42 0.68 0.36 - 1.29 0.58 0.66 0.86 0.18

3. 0.42 0.67 0.36 - 1.17 0.61 0.74 0.77 0.174. 0.48 0.68 0.36 - 1.00 0.56 0.40 0.67 0.10

5. 0.38 0.67 0.37 - 1.02 0.53 0.75 0.63 0.12

6. 0.42 0.67 0.36 - 1.13 0.56 0.71 0.78 0.15

7. 0.43 0.67 0.36 - 1.03 0.52 0.82 0.78 0.16

It is observed from Table 2 that the actual temperature

differential on day three and day ve during summerseason is very low. This is because on these days the

pavement top temperatures dropped when it became

cloudy and there were sudden heavy rainfalls during

the day. After the rain ceased the sky remained cloudy,

that prevented any possibility of increase in pavement

top temperature. It is observed that the temperature

differential from predicted models is slightly more

than the actual temperature differentials, except for

summer season. This could be due to sudden rainfall

on two days. Similarly the temperature stresses

evaluated from the prediction models are on the

higher side. Fig.4 shows the comparison between

actual temperature stresses and predicted temperature

stresses during winter season at edge region.

Fig.4 Comparison Between Actual and Predicted Temperature Stresses


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7 CONCLUSIONS

Analysis of the instrumented concrete slab temperature

data recorded for the three season’s summer, winter

and monsoon yielded the following main ndings:

● The air temperature, solar radiation andhumidity are factors inuencing temperaturedifferential in concrete slabs.

● Negative night time temperature differentialvalues are less signicant than positive day timetemperature differentials. Moreover, negative

differentials occur much less often than positive

differentials.

● There is not much difference between average

air temperature during winter and monsoonseason.

● It is observed that the minimum top temperatureduring summer, winter and monsoon season is

22.8˚C, 21.30˚C, and 21.10˚C respectively.

● It is observed that the maximum top temperaturesduring summer, winter and monsoon season are

53.9 ˚ C, 42.30 ˚C and 38.60˚ C respectively.

● The maximum pavement top temperature during

summer is 21.5% higher than that during winterand 28.4% higher than that during monsoonrespectively.

● The pavement top temperature and thetemperature differential are lower during

monsoon than winter; this can be accredited

due to the presence of clouds thus causing

lesser solar radiation.

REFERENCES

1. Choubane and Tia, 1995 “Analysis and Verication ofThermal Gradient Effects on Concrete Pavements”,

Journal of Transportation Engg., Vol. 121, No. 1.

pp.75-81.

2. IRC:58 “Guidelines for the Design of Plain Jointed Rigid

Pavements for Highways” The Indian Road Congress,

New Delhi.

3. Khanna S.K. and Justo C.E.G. 1996, “Highway

Engineering,” Nem Chand & Bros Roorkie.

4. Liu Wei, 2005, “Improved Model for Analysis of

Load and Thermal Effects on Concrete Pavements”,

Ph.D. Dissertation Report (Unpublished) submitted to

Department of Civil Engineering, National University of

Singapore.

5. Yang H. Huang, 1993, “Pavement Analysis and Design,”Prentice Hall.

6. Yoder E.J. and Witczak M.W., 1975, “Principles of

Pavement Design”, John Wiley and Sons Inc.

7. Wei LIU and Tien Fang FWA, 2003. “Effects of Nonlinear

Temperature Distribution on Thermal Stresses in Concrete

Pavements”, Journal of the Eastern Asia Society for

Transportation Studies, Vol.5, pp 1023 to 1034.

8. Puttappa C.G., 2006, “Investigations on High Performance

Cement Concrete for Pavements”. Ph.D. Dissertation

Report (Unpublished) submitted to Bangalore University.

9. Jose T. Balbo, Andrea A. Severi, 2002, “Thermal Gradientsin Concrete Pavements in Tropical Environment: An

Experimental Appraisal”, Laboratory of Pavement

Mechanics, Sao Paulo, Brazil. TRB paper No. 02-2560.


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Audit involves ofcial inspection of an organizationaccount typically by an inspecting body. In respect of

concrete structures it will mean a critical inspection of

concrete structures, ascertain damages, distresses and

defects appeared during construction or in service life.

The author had an occasion to inspect more than 100

concrete structures which developed either problem

during construction or during in service life, if these

are summarized subject wise, the main issues are as

below:-

A concrete structure is subjected to the effect of water,

disturbances in the earth such as settlements and

earthquakes, the effect of wind and environmental

effects. In ancient Vastushastra there used to be a

prayer at the foundation ceremony and even at the

completion of the work stating that “Let the god of

Rains (Varuna) protect this Vastu, let the earth on

which Vastu is laid protect it from destruction, let the

effect of wind and let the god of Environment protectthis structure”.

In the concrete structures which developed some

defects following main issues cropped up:-

1. Erosion and cavitations of Bridge piers and

foundations due to high velocity.

2. Damage of concrete in buildings and bridges

due to Alkali-Silica Reaction (ASR) or Delayed

Ettrigingite Formation (DEF).

3. Plastic Shrinkages in the newly laid concrete

due to lack of appropriate curing.

4. Inappropriate construction methods.

QUALITY AUDIT FOR CONCRETE CONSTRUCTIONS

DR . C V KAND*

5. In respect of Aqueducts damages caused due

to failure of joints and rubbing of canal water

containing sand and pebbles on the bottom

surface of the ducts are seen.

6. Wrong procedure of well sinking and instances

of well sinking in rock.

1 EROSION AND CAVITATIONS

(Fig. 1.1, Fig. 1.2, Fig.1.3)

1.1 Hydro Dynamic Effects

According to current practice and codal requirements,

bridge piers are designed for the static effects caused

due to velocity head, differential head etc. Recent

observations have shown that the bridge piers are

subjected to hydro-dynamic effects such as erosion

and cavitation caused at high stream velocities. The

hydro-dynamic effects are smaller and insignicant

at lower stream velocities and may be ignored but at

higher velocities these effects can cause damage and

failure of structure.

In high level bridges hydro-dynamic effects are

predominantly on piers. Effects on abutments are

not signicant. In submersible bridges the decking,

is subjected to hydro-dynamic effects which are

ultimately transferred to piers. The theoretical background and method of assessment of the effect

is well known. The same is, however, critically

examined, in the light of bridges.

* Retd. Chief Engineer, PWD, Bhopal (MP), E-mail: [email protected]


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1.2 Erosion Due to Suspended Particles in

Streams

Rivers which carry coarse sand or gravel of large

pebbles wears away the masonry or concrete of piers

through abrasion. The deterioration of the submerged

surfaces of masonry or concrete brought about by the

abrasive action of solids in motion in uids is callederosion. The rate of erosion is dependent upon the

following factors.

i. Quantity of sand and gravel in water.

ii. Shape, size and hardness of particles.

iii. Velocity of the current.

There is a relationship between the competent bottom

velocity (the velocity at or above which a certain

particle can be transported) and the size of particle

dragged by the stream. This is given by d = 36.15 V b2

where d is in mm and V b is in m/sec.

The diameter of particles own by current for variousvelocities will be

Velocity m/sec Diameter mm

1.5 80

3.0 330

4.5 730

6.0 1300

7.5 2030

9.0 2930

Model studies, to establish quantum of erosion of

surface of structure in a given period at different

velocities of current in sandy bed, are not available.

According to ACI, if the quantity and size of solids

are small; for example silt in irrigation canal, no

appreciable erosion takes place on good concrete

surface at bottom for velocity up to stream velocities

of 3m/sec. Signicant erosion effect has been observedin structure in sandy river beds where the velocity of

current is more than 4.5m/sec. Hard stone masonrystructures can stand higher velocities without abrasive

action.

Erosion of surface of submerged concrete structure

will take place at velocities higher than 3m/sec. even

if the ow is undisturbed and the shape of the surfaceis smooth and streamlined. If the shape of structure is

not streamlined and the surface has depressions and

there are projected corners, the ow will be disturbed.Separation of ow and formation of eddies will take place at such even spots. The velocity at the disturbed

zone will increase and the stream would scoop out

more quantity of sand from the bed. Increase in

quantity of sand and increase in the velocity will

thus aggravate abrasive action at uneven and un-

streamlined spots in the structure. Movement of sand

is vertical due to pushing up from bed by whirlpool

action and horizontal due to current.

Fig.1.1 Shape of Piers and Current Directions at Pier.


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1.5 Hasdeo Bridge at Champa

In 1956, a submersible bridge was undertaken across

Hasdeo River velocity of current is 9m/sec. During

construction some foundation and decks got washed

away in oods, due to high velocity. The bridge wasthen converted into a high level bridge. The high

level bridge is provided with some wall type piers

and some piers with 3 circular columns connected by

diaphragms. Within 3 to 4 years of completion, it was

observed that surfaces of concrete are eroded exposingthe metal in concrete matrix. Colcrete steining of one

of the well foundation was damaged in nearly 75%circumference of upstream dredge hole of an ‘eight’

shaped well. Depth of damaged portion was 1.8m. In

another well, after damage of colcrete steining, RCC

columns inside were also damaged due to erosion.

These damages were obviously due to erosion caused

by high stream velocity and further that the concrete

was not suitable to withstand the fury of water currents.

The plain concrete piers of Railway Bridge on d/s of

this road bridge also showed surface erosion. The

old railway bridge was provided with stone masonry piers. The bridge was deserted. However, one pier

is standing. The stones of the masonry have large

bushes. The bushes show seriations along bedding

plane of the stone due to erosion. The case shows that

circular columns with diaphragms are not suitable for

high stream velocity. Detailed investigation of this

case brought out that specications of concrete piersmust be compatible with stream velocity. Colcrete is

not suitable for well steining. It is not being used now

a day.

1.6 Deolon Bridge (Sone River) Near Shahhol

(M.P.)

This submersible bridge was completed in 1950.

In the oods of 1975 the bridge was submerged fornearly 36 hours with 5.8m, water above the bridge. On

receding of the oods it was noticed that the bridgehad almost completely washed away. Maximum mean

velocity of the stream was 6.1 m/sec. At 300m on the

downstream, rocky hillocks project in the river on both

banks. The channel is constricted and the river takes

a sharp turn. All these caused disturbance of the owand increase in velocity. The structure was designed

for a velocity of 3m/sec only. It was noticed that piers

fell in different directions. Foundations of the bridge

were laid on bouldery strata. Some piers got uprooted

even from foundation level. Investigations showed

that at the location where river width is constricted

there is a fault zone, a deep hole in rocky bed having

depth of 15m. This has occurred due to high velocity

of water at construction site.

A tower of a high power line on the bank of river

consisted of 4 steel rail sections. The rails sheared off

at the top of footing of the concrete block as if cut by

a hacksaw. A large vortex was formed at the bridge

site on account of physical features and it appears

the tower was in worst zone of the vortex. This was

a typical effect of cavitation, caused due to vortices

Fig. 1.3


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at high velocity as explained in previous paragraph.

Fall of piers was not along the direction of river. Piers

fell in various directions and this shows turbulent owhaving deviations angles larger than 200. Inadequate

assessment of velocity, bad seating and foundations

on Bouldary strata are the causes of failure of the

bridge.

Photo 1.1, Photo 1.2, Photo 1.3, Photo 1.4 and

Photo 1.5

Cavitations and Erosion Damages

Photo.1.1 Photo.1.2

Photo 1.3 Erosion of the Stone Masonry at High Velocity


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2 ALKALI SILICA REACTION (ASR) OR

DELAYED ETTRIGINGITE FORMATION

(DEF)

2.1 Alkali silica (aggregate) reaction is a recent

phenomenon and is known as cancer of concrete. It

attacks when moisture for one reason or another gets

into the concrete structure and reacts with the alkali

produced by certain types of cements. The resulting

alkaline solution then reacts with silica found in

some types of aggregate and sand and make the gel

a powerfully moisture attracting element. The gel

expands as it gathers more moisture and causes the

concrete to crack. These cracks allow more moisture

into the concrete and the problem gets worse. Several

concrete structures in U.K. have suffered premature

damage due to ASR. In India recently, we have come

across this phenomenon in Hirakud dam spillway and

Rihind dam power house structure and repairs are

done. High alkali content in cement also causes ASR.

Cements in India contain 0.4 to 1 percent alkali. It

is advisable to restrict it to 0.6 percent. The reaction

takes place in presence of moisture. Alkali silica

reaction can be controlled by selection of non-

reactive aggregate, use of low alkali cement, by

adding pozollana in cement, by controlling moist

condition. Alkali silica reaction will be at surface

due to presence of rain water. Surfaces can be given

waterproong paint treatment to minimize the effect.ASR occurs only when aggregate contains such

element which can react with alkalis in cement. It

does not occur in all concretes. ASR cause pot holes

in deck slab of bridges. Such holes were observed in

several bridges in western Madhya Pradesh where

local sand was used. This local sand contains 30%

Ferruginous compounds. The tests were carried out at

National soil and material laboratory at CWPC, Delhi.

IS 383 (Table 1) says that deleterious material should

not be more than 5% in river sands. Chemical tests of

sand should be obligatory.

2.2 Delayed Ettringite Formation (DEF) – in steam

cured precast concrete slabs of M40 strength, the slabs

were staked and these were to be placed on precast

girders and provide composite deck slab. Several cracks

were noticed in the precast slabs. This can happen due

to: a.) presence of sulphate in aggregates which cause

delay in gaining strength, this phenomenon is caused

due to delay in Ettringite formation. However, there

are no precedence of DEF in India. b.) If water cement

ratio in precast steam cured slab is less than 0.4 the

slabs have to be cured for two days after removal from

the steam curing. According to Neveele if this is not

done cracks appear in the slab.

Photo 2.1, Photo 2.2 and Photo 2.3

Photo 1.4 Cavitation Damage

Photo 1.5 Cavitation Damage


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3 CRACKS IN DECK SLAB OF THREE

BRIDGES

3.1 Background

Cracks in the deck slabs of bridges were observed in the

longitudinal and lateral direction of three Bridges.

3.2 Nature of Crack:-

In Bridge No.1 the cracks are in the longitudinal and

lateral directions over the location of steel. Width

of crack at top of slab was found to be 25,15,10,10

and 5mm at ve locations, there are 36 cracks in thewidth of 11.2m. In Bridge No.2 & 3 similar cracks

were observed. Cracks in Bridge No.1 & 2 are

wider, in Bridge No.3 Cracks are not wide but these

are throughout the span. At bottom of slab, precast

concrete sacricial slab was used as a formworkand hence it was not possible to see if cracks have

occurred. However, the core data showed that cracks

are not extended generally below top of steel in top

slab.

3.3 The Likely Reasons of Cracks are Generally

as below:-

1. When steel inside the concrete is corroded, its

volume is increased and the concrete cracks,

such cracks are found along the vertical steel in

columns and at the bottom of deck slab.

2. Cracks can also occur due to defective that is

weak concrete.

3. If the Structure is in hot areas and where hot

winds are present and where curing of concrete

is not started as per the requirements of the type

of cement used, plastic shrinkage cracks occur.

3.4 Material Used & Method of Construction

The materials used in all the bridges is crushed granite

aggregate of black colour, the river sand, Grade 53

cement of Ultratech (as per clause 302.1 of IRC:21

& IS 12269), construction chemicals (IS-9103), water

for concreting. All these materials have been tested

according to codal requirements and no defect was

found in the materials of concreting. Aggregate &

sand are as per IS 383. Testing of these is as per IS

2386. Concreting was done by using concrete pumps

and the slump was 80 to 100mm. This is also alright.

Cement and Fly Ash: Ultratech cement of 53 Grade is

used for the RCC work. But this also causes shrinkage

effects as observed in many Bridges and Buildings.

Photo 2.1 RCC Box Type Deck in an Area Which Contains Sand

with Ferruginous Compounds

Photo 2.2 Beginning of Pot Holes in Deck

Photo 2.3 Pot Holes in Deck due to ASR


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For RCC bridges & buildings grade 33 or grade 43 are

preferable. However there is no codal ban on using

53 Grade cement for RCC work. 20% Fly ash if addedin the cement, this should in fact reduce shrinkage.

The above information reveals that there is no faultin the material used or in the procedure of concreting.

It is therefore necessary to examine the procedure

adopted for curing of concrete.

3.5 Testing of Concrete Laid at Site by Non

Destructive Tests

Following Non-Destructive test were carried out:

1. Ultrasonic Pulse Velocity Test and 2. Core Test

UTPV test show that there are no doubtful or medium

results. The depth of crack was also measured and itwas found to be from 20mm to 40mm that is up to the

top of Steel bars only in one case the depth is more.

3.6 Reasons for Cracks

Since the materials used for concreting and the method

of concreting did not display any defect, cracks might

have occurred due to method adopted for curing of

concrete in the hot weather with low humidity which

is prevalent in this region. The record of temperature

during concreting and the ambient temperature

shows that the bridges are located in hot region and

the temperature during concreting has been more

than 30ºC. It is a hot area where besides temperaturehot winds also exist. It appears, on completing the

concrete curing or watering of concrete was started

late. Normally when Grade 53 cement is used the

practice is to cover the concrete by Tarpaulin placed

on test cubes on fresh concrete so that Tarpaulin does

not touch the concrete. After 2 hours ponds are made

with earth and these are gradually lled with water. If

curing is delayed and if the concrete is in hot weather,it suffers from plastic shrinkage. Since the steel

reinforcement is approximately has 40mm cover, the

shrinkage will go up to the top of the steel bar without

interruption. It cannot go deeper due to presence of

bar and the cracks will be developed on steel along

the direction of steel. This is what appears to have

happened at site as can be seen from photographs of

cracks.

3.7 Plastic Shrinkage Cracks

The American concrete Institute in ACI 116 denesPlastic Shrinkage Cracking as cracking that occurs in

the surface of fresh concrete soon after it is placed and

while it is still plastic. These cracks forms becauseof loss of bleed water from the surface of the fresh

concrete by evaporation. The tensile strength of fresh

concrete is very low since the concrete has not had time

to set, the volume changes caused by this evaporation

of the bleed water results in the formation of plastic

shrinkage cracks. The critical condition exists when

the rate of evaporation of surface moisture exceeds

the rate at which the rising bleed water can replace

it. Water reaching below the surface forms menisci

between ne particle of cement and aggregate causinga tensile force to develop in the surface layer. If the

concrete layers have started to set and has developed

sufcient tensile strength to resist the tensile forces,cracks do not form. If the surface dries very rapidly,

the concrete may still be plastic, and the cracks do not

develop at that time; but the plastic cracks will surely

form as soon as the concrete stiffens a little more.

3.8 Rehabilitations Measures

The test results show that the strength of concrete

is not reduced. There is no need of providing epoxyconcrete. However, cement mortar 1:1.5 with ne sandand 15% polymer should be grouted. The procedurefor grouting will be to make small holes in the concrete

going up to 30mm at 300mm c/c. An area of about

1m x 1m be selected and perplex pipe of 10mm

diameter be xed in the holes, all except one hole beclosed at top and grouting should be done at pressure

from the open hole till the grout comes in the other

holes. A specialized agency be engaged to do this work.

In this manner grouting should be done and the wider

cracks be nished by the same mortar if not lled bygrouting. In future the freshly laid concrete be covered

by Tarpaulin and placed above test cubes as mentioned

above, after about 2 hours. Earthen pond be made and

water should be lled in the ponds gradually, 7 daysafter grouting the wearing coat can be laid. IS: 456

of 2000 Para 13.5 contained instructions for curing.

These should be followed.


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Photo 3.1, Photo 3.2, Photo 3.3 and Photo 3.4

4 INAPPROPRIATE CONSTRUCTION

METHODS

Geotechnical investigations was carried out for two

separate bridges. Each bridge has two separate 2-lane

bridges. Thus there are total 4 bridges which contain

18 well foundations. Geotechnical investigations was

carried out by three different organizations namely

by DPR consultants, by proof consultants and also by

the contractor. All these three separate geotechnical

consultants concluded that the soft rock is available

at different depths in the well foundations, and

recommended Safe Bearing Capacity of not more than80 T/m2. The design consultants proposed sinking of

wells 5 to 7m in the soft rock and considered passive

resistance in the design of wells, when the work was

in progress sinking of wells in rock could be done

only by blasting. In that process the wells are

● badly tilted and shifted,

● the well steining is cracked

The investigation of these tilted and shifted well

was carried out and following glaring facts came tonotice.

i. In about less then 300m from the site of these

bridges there are existing bridges constructed

before Independence during British regime.

These are submersible bridges. The bridge

register shows that the foundations are taken

only 4m below the bed level and laid on hard

Photo 3.1 Plastic Shrinkage

Photo 3.2 Plastic Shrinkage on Location of Steel Bars

Photo 3.3 Core Test

Photo 3.4 Core Test


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rock. However, this data was not collected

during geotechnical investigation.

ii. During sinking of the well large pieces of rock

extracted by blasting could be seen at the site

near the wells. Cubes of 100 mm x 100 mm x

100 mm were chiseled out from these pieces

and tested in the laboratory. In one case the

safe bearing capacity was 300 T/m2, in another

case it was 400 T/m2 (by adopting factor of

safety 8) against the recommended capacity by

the geotechnical experts of 80 T/m2.

iii. The rectication of tilted and shifted pier wellswhich is causing more than 33% base area in

tension is being done by providing Anchorrods in the tension zones and also all around

the periphery. 32 mm Anchor rods are anchored

2.5 m in rock and grouted by 1:1.5 cement

mortar with 15% polymer. 2 bars of 32 mm are proposed to be anchored in 110 mm diameter

bore. The bars are raised and anchored in the

well cap with transverse circular stirrups. These

anchor rods will take entire tension coming

on the foundations and the direct load will be

taken by the rock below. The cracks in the wellsteining have occurred because of blasting.

These will be grouted by 1:3 Epoxy mortar. The

entire well is lled up by concrete of the samestrength of well steining.

iv. In respect of abutment well there are 2

alternatives:

a. To provide pre-stressed concrete active

anchorages and x them in the rock below and in the well cap above.

b. To provide RCC block wall near the well

and lay the well cap on the well and this

block with a view to relive the well from

lot of tension and provide also some

anchor rods, similar to pier wells.

v. IRC:78 clause 705.3.2 recommends that in

case of hard rock the seating of the well shall

be such that the 75% perimeter is seated onrock and a sump (shear key) of 300mm is

cut in hard rock and 6 dowel bars of 25 mm

diameter are anchored in rock. The same code

also recommends that the boring chart shall bereferred to constantly during sinking for taking

adequate care while piercing different type of

strata by keeping boring chart at the site and

plotting the soil as obtained for the well sinking

and comparing it with earlier bore data to take

prompt decision. Ignoring these precautions can

cause distresses of the type as explained above.

There is no fault of concrete; the fault lies in the

construction methodology.

Photo 4.1, Photo 4.2, Photo 4.3 and Photo 4.4

Photo 4.1 Tilted Well

Photo 4.2 Tilted Well


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5 CONDITION SURVEY OF AQUEDUCT

CUM BRIDGE

5.1 Background and Details of Aqueduct

This Aqueduct cum Road Bridge was completed in

March 1991 on lump sum contracts with contractors

design. It is now about 20 years old. Certain problems

are being faced in the Aqueduct.

The structural details of the Aqueduct are as below

Total Length 966 meters

Span arrangement 19 spans of 38.5 metres

main spans

10 spans of 9.97 metres

Height from Lowest 33 m

bed to Soft

Duct size Twin duct 3.425 x 2.60

5.2 Observations

5.2.1 The conventional copper expansion joint are

provided on the inner side of the duct. There is a gap

of 50mm on the inner side of the aqueduct wall. This

is lled up by Shalitex board to make it water tight.While nalizing the estimate there was a proposal to provide 25mm water proof coat on the inside of the

duct. It was however proposed to do after observing

the performance of the aqueduct during its operation.

5.2.2 Canal water coming from Dam carries sand

and pebbles and these rub on the top surface of the

bottom slab of the duct. Concrete is badly eroded and

aggregate get exposed.

5.2.3 Besides Sand and the pebbles as mentioned

above some larger stones of the size of masonry

stones were found inside the duct. Nobody could

explain how these stones have come because such

stones cannot ow with a small velocity of 3.9 m/s.These appears to have been brought later and may be

for some maintenance operation but not removed.

5.2.4 Five Expansion joints of the aqueduct are

damaged by miscreants who have broken the concrete

outside the copper plate in the joint and removedthe copper plate. There is a leakage through joints

when the canal water is let in the vertical steels in the

concrete which was broken is exposed at some place.

5.2.5 The Shalitex board at joints which are not

broken is also damaged at places. The depth of water

at highest water level inside the canal is only 2.5 m.

5.2.6 The expansion joints at road level are only in

the road way width. These are not extended in the

footpath portion; therefore the rain water is leaking

through the joints and caused dirty water marks on

the soft of cantilever slab, on the vertical sides of theducts. Then due to water owing from the top of piercap down to the pier such dirty water marks are also

seen on the pier.

5.2.7 The aqueduct was inspected after severe

Earthquake of 1997. It was brought out that plants have

Photo 4.3 Tilt & Shift

Photo 4.4 Tilt Being Reduced by Eccentric Loading


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sprouted on the pier cap and at the expansion joints

outside. It was suggested that this should be removed

and the roots lled with lime powder and Asafoetida.Generally these are Pipal trees. It appears that this has

not been done; more such plants are supported on pier

cap.

5.3 Causes of Distresses and Rectications

5.3.1 The canal water in the aqueducts bring with

it silt, sand and pebbles. These ow along with thewater slowly but when the discharge is stopped these

get accumulated and the ow characteristics expectedin the aqueduct is affected. That is why water gets

stagnant inside the aqueduct even when the canal

discharge is stopped. Inquiry reveled that there is no

maintenance manual for the aqueduct. Criterion for

the maintenance for the bridges is adopted for the

aqueduct. But the IRC criterion does not have any

guidelines for the ow of water inside of the duct andthe expansion joints in the duct. It has now become

necessary to have such a maintenance manual for the

aqueduct which will take into account the effect of

ow inside the duct.

5.3.2 These types of expansion joints are giving

trouble in many aqueducts. Incidences of braking of

joints with a view to remove costly metal like copper

plates are observed. This is an age old joint and

its replacement is not easy. In case of bridges strip

seal expansion joints are provided replacement of

these joints is simple. Polymer expansion joints are

available It is better to change these expansion joints

by elastomeric expansion joints.

5.3.3 It is advised that details of the expansion jointand the procedure of its xing should be obtained fromthe manufacturers. Normally the expansion joints are

xed by the manufacturer and they take the guaranteeof its functioning.

5.3.4 It has been brought out that the top surface of the

bottom slab has eroded. Erosion resistance capacity of

M35 concrete is rather low. However, epoxy mortar

with three parts of calcenite sand and one part of

epoxy has erosion resistance nearly three times than

that of M35 concrete. Therefore 15mm thick epoxy

mortar should be laid over the bottom slab and also

on the sides of this aqueduct to improve the erosion

resistance.

5.3.5 The accumulation of sand, silt & pebbles shows

that duct has not been cleaned for years. It is felt that

every year this must be cleaned at least twice once

before the ood season and second after the oodseason.

5.3.6 The canal alignment on both sides also needs to

be cleaned of the debris and branches of trees, which

get accumulated around the columns in the transition

structures. It is better to avoid columns in transition

structure as has been done in recent aqueducts.

5.3.7 The erosion of concrete in the piers and wells is

not signicant at this stage but this should be observedevery year.

5.3.8 Wherever stalactite phenomenon is observed it

is due to minor leakages. It is advisable to grout these

spots by cement grout and stop these leakages. Since

this is bridge cum aqueduct, the bridge engineers

cannot ignore such defects in the duct.

Photo 5.1, Photo 5.2, Photo 5.3, Photo 5.4, Photo 5.5

and Photo 5.6

Photo 5.1 Erosion at Base of Aqueduct


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6 AUTOGENEOUS HEALING OF

CONCRETE (Figs. 6.1 and 6.2)

6.1 Human body has a property to heal up woundsand restore it to its original texture. Similarly, it is

observed that observed that cracks in concrete also

heal up. Three examples are cited.

6.2 In one bridge 15 m precast pre-tensioned

girders closely spaced (18 girders in a width of

8m) are provided. The pre-tensioned girders were

brought on the river bank and stacked on the river bed

Photo 5.2 Damage of Expansion Joint.

Photo 5.3 Obstruction at Canal Transition

Photo 5.4 Stalactite Phenomenon

Photo 5.5 Damage at Junction of Well Cap and Well Steining

Photo 5.6 Expansion Joints in Aqueduct


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before lifting. 4 girders showed cracks at mid span.

Investigation showed that only half length of the

girder was supported on bed and the remaining half

was overhanging. These girders were not designed

for such a cantilever prole. Vertical cracks occurredat the mid span. When the girders were placed on

level supports on both ends cracks closed. Water was

sprayed for 24 hours on the girders. Cracks healed up.

This is called autogenous healing of cracks. One girder

was then tested for full design load and it behaved as

expected like an un-cracked girder. Four such girders

are used in the bridge two girders at each end and

bridge is serving the trafc since 1964 without anytrouble.

6.3 It was decided to erect a small full scale model

with ve girders on the bank and test it for destructionwith a view to ascertain share of load among girders

and maximum destruction load. Two and half times

design live load was placed. More than 100 cracks

developed but the structure did not collapse. Loadwas retained for 48 hours and then removed. This was

in 1969. The model is preserved at site. Not a single

crack was visible when observed on 19/6/97. Cracks

closed.

6.4 An RCC bracket was constructed at site and it

was desired to ascertain destruction load and behavior

of joints. Two and half time design load was placed

and retained for 48 hours. Bracket cracked profusely.

This was in 1980. The bracket was retained. In ood

of 1996 it fell down. All cracks have healed up.

Load Test for Destruction, Cracks Totally Closed on Removal of Loads.

Model Preserved at Sher Bridge Near Narsinghpur in Madhya Pradesh.

Fig. 6.1 Fig. 6.2

7 CONCLUSIONS

The Audit for quality control Constructions of 6 case

studies deliberated in this paper has brought out thatsome distresses in the concrete bridge structures have

occurred not on account of any defect in the concrete.

These have occurred due to inadequate appreciation

of forces of nature like water current and environment

or due to wrong methods of construction. Following

lessons should be kept in mind:-

1. The shape of bridge piers and specication of

concrete should be compatible with the velocity

of the stream.

2. Velocity of the stream more than 6m/sec cancause not merely hydro-static effects but also

hydro-dynamic effects such as erosion and

cavitation of piers and this should be considered

in the design and specications.

3. If the chemical impurities in the aggregates and

sands are more than 5% (IS 383) it can causeAlkali-Silica reaction, which is the cancer of

the concrete. Therefore, aggregate and sands


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should be tested for chemical impurities.

4. Cracks caused in concrete structures can be

autogenously healed by removing the causes of

the cracks and constantly watering the cracked

concrete for 24 hours. Such cracked beamswhich are healed up are provided in bridges and

are surviving for more than 25 years.

5. The green concrete done in hot weather (more

than 30ºC) should be covered by Tarpaulinand providing water ponds for curing after 2

hours. It is extremely necessary to follow the

precautions of curing contained in clause 13.5

of IS 456 of 2000. This is more obligatory for

structures where Grade 53 concrete is used. If

the precautions are not taken, Plastic Shrinkage

cracks occur on the surface of concrete slabs.6. The bed level inside aqueducts gets badly

eroded on account of sand and pebbles owingin canal water. It is therefore, necessary to

provide epoxy mortar 1:3 on the inner surfaces

of aqueducts below water level.

7. The conventional expansion joints of aqueducts

are not easy to replace. The copper plate is

broken and stolen. It is advisable to provide

polymer type of expansion joints. The surfaces

of concrete where steel is exposed & corroded

should be repaired by polymer modied mortar

on removing the rust on steel bars by sand blasting or by chemicals.

8. While carrying out geotechnical investigations

the foundation levels and the type of strata in

the existing bridges must be investigated and

the actual strata obtained during sinking be

compared with the data given in the bore log

and modications may be carried out in thedesigns if necessary.

9. Expected life of concrete structures is 100

years. This life can be ensured by keeping in

mind some of the issues during constructionas mentioned above and also by frequent

inspection i.e. Audit for quality concrete.

REFERENCES

1. Hydraulic investigations and problems of Bridges by

C.V.Kand & A.K.Saxena, IRC 1989.

2. Environment and materials investigations and problems

of Bridges by C.V.Kand, IRC 1997.


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ABSTRACT

The last decade witnessed unprecedented raise in output to the

tune of 7% of world’s GDP. The BRIC countries contributedlargely to this unprecedented growth. Paradoxically, the gathered

momentum of growth rate of Asia Pacic region had made thedeveloping countries to subtly suggest the growth as a proigacytowards un sustainability demanding in the controlled growth rate

who were ironically talking about red tapism and bureaucracy not

in very far past.

Ironically, by the turn of 2008 and the beginning of 2009, the

global recession led by United States had put India and Chinaon centre stage, where they were expected to play major roles

in reviving the world’s economy by growth rates enabled by

mammoth infrastructure development plans. As this paper being

written during August 15, 2012, once again the European and

Western economies which were showing the signs of recovery till

then, seem to be plummeting.

With the emphasis on fast growing economy, the developing

countries will aim at achieving the above by creation of

facilities to provide housing, sanitation and water supply, public

transportation facilities, reach-ability to education and adequate

employment opportunities which demands mammoth materials

and energy consumption.

Apart from this, the governmental efforts to bring in vast foreign

investment to cater for thickly populated big markets, will warrant

major chunk of the allocation in the plans for infrastructure

development, where the civil engineering fraternity can contribute

in optimizing and reducing the costs of the projects, which can be

used for further sustainable development.

Whenever, the sustainability in construction is addressed and

discussed in any kind of forums, it is always conned to that part ofconcrete technology where Ordinary Portland Cement is partially

replaced by mineral admixtures to reduce energy consumption

from fossilised sources and also CO2 emissions to environment.The author has been advocating sustainable construction beyond

this connement by extending the same to Value engineering,Rationalization of codes, Hazard mitigation, New technologies

and materials, Sustainable structural systems since 2002 in

National and International forums.

SUSTAINABILITY, CHALLENGES & OPPRTUNITIES

IN BRIDGE BUILDING

V. N. HEGGADE*

1 INTRODUCTION

By virtue of enormous performance of China, India

and Russia in 2007, the world output was raised by 7%in GDP (with out adjusting for ination), catapultingthe world economy. The Chinese and Indian economy

with its unprecedented economic growth of more than

5% might have potentially elevated the Asia and pacicregion on par with economies of European Union and

United States with in a decade. The alarming growth

rate of the developing countries caused concerns to

the globe as a whole as there were sufcient evidenceto establish the relationship between depletion in non

renewable energy resources (fossilised) with Climate

change and the Growth rate.

The Fig.111 projects the accelerated consumption in

non-renewable energy sources while the GHG (Green

House Gas) emissions leading to climate change as

presented in Fig.211 depicts that the emissions in

developing countries would cross over developed

countries by around 2015.

* Member-Board of Management, Gammon India Ltd., Mumbai, E-mail: [email protected]

Fig.1 Projected Energy Consumption Sources


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While the energy consumption

per capita of developed countrieswhose GDP is high, is glaring

from the Fig.3 that warrants the

austerity measures for reducing

the consumption, the developing

countries like China and India

whose growth rates are high

have also very high population

(Table 1) which can make the

consumption leapfrog for a small

increment in growth rate.

paradoxically, the developed Western and European

world are in the phase of their infra structure

maintenance as such have to nd market in developingcountries for their growth.

Obviously, the statistics above indicate that the

countries living standards improve with the increase

in the GDP and decreases with enhanced population.

The increased consumption of energy and materials

culminate in the growing accumulation of construction

waste, hazards and emissions, necessitating the

sustainability options to reduce the depletion in non

renewable energy resources and potential climate

change and their consequences.

2 SUSTAINABLE CONSTRUCTION

Whenever, we are talking about sustainability in

transportation sector, we are inadvertently pushed in

to ancient realm of bridges, materials and practices

that are testimony of endurance. It is not surprising

that the English word sustainability itself has its origin

in ancient Latin word ‘sustenere’, meaning long term

compatibility. Hither to, though the methodology to

quantify the sustainability measure is not evolved, there

are universal indicators viz Ecological, Economical

and Social8. (Fig.4)

Fig.2 Green House Gas Emission by Region

Fig.3 Energy Consumption Country Wise

The strongest enabl

Indian Highways Vol.41 5 May 13

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Transcript of Indian Highways Vol.41 5 May 13