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TRANSCRIPT
• From the President’s Desk 1
• News from Centres 2
• Selected Seminar Papers 7
• ICI Students’ Chapters 20
• Forthcoming Events 25
• New Members 26
Contents
From the President’s Desk
May 2011 Vol. 2 Issue: 05
ICI Update – May 2011 01
One welcome trend which is clearly discern-ible during the recent past is the consistent growth in the addition of stu-
dents’ chapters. ICI has been add-ing at least one student chapter every month during the past more than a year. This issue contains re-ports on new students’ chapters, including the one at IIT Madras. Local ICI centres should take a clue from this trend and devote lit-tle more time and efforts in bring-ing students of civil/structural/environmentalengineering from their region into the ICI fold. ICI members who hold faculty posi-tions should encourage students to open chapters in their respec-tive colleges. I am initiating a proposal to give a further boost to this trend, so that the student fraternity feels that they are real beneficiaries. The proposal will be discussed during the next Govern-ing Council meeting.Incidentally, I feel that we need to take serious cognizance of the recent events in Japan. All of us were shocked and greatly per-turbed to witness the catastro-
phe created by the earthquake and the tsunami that had struck Japan on March 11, 2011. The ef-fects of the sad event are still un-folding. According to the United States Geological Survey (USGS), this earthquake was the largest ever recorded in Japan and is the world’s fifth largest earthquake to strike since 1900. Japan is believed to be well-equipped and prepared to resist earthquakes of high in-tensity; yet the devastations were horrendous. The tragic events in Japan raise many questions amongst Indians, especially amongst the engineer-ing fraternity. Is India prepared to withstand high-intensity earth-quakes and tsunamis? Prime Minister Dr. Manamohan Singh was quick to order a “technical review” of all critical installations. The safety of critical structures in-cluding nuclear installations is cer-tainly important. However, equally pertinent question is about the safety of all structures in densely populated urban or rural areas. In recent years reasonably high-intensity earthquakes have struck India in quick succession: Khilari (Latur) in 1993, Jabalpur in1997, Chamoli in 1999, Bhuj in 2001, An-daman in 2002, Sumatra in 2004,
Kashmir in 2005 and Sikkim in 2006. It is estimated that nearly 70% of the Indian land mass is prone to medium-to-high intensity earthquakes. Despite certain laud-able efforts of many organizations and individuals, the awareness about earthquake-resistant design and construction is still lacking in India. Are we are in a position to state confidently that the coun-try is well prepared to withstand large earthquakes? Certainly, we have a long way to go in achiev-ing tangible results in earthquake-preparedness. Any earthquake is a sad reminder to us about our shortcomings. In fact, we should consider it as a wake-up call.In this issue, we are including a write-up by Prof C V R Murty on the theme “Preparing for Earth-quakes: Where India Stands?” Considering the sensitivity of the topic, we would welcome worth-while contributions on this theme and request readers to respond at an early date. The contributions can also cover the role that ICI can play in creating awareness and ren-der help in building earthquake-resistant structures in India.
Vijay KulkarniPresident
ICI AWARDSNominations are invited for the following ICI Awards for the
year 2010-2011
1. Outstanding Concrete Structures.
2. Outstanding Concrete Technologist.
3. Best Paper published in ICI Journal.
4. Best Paper on Construction Techniques.
5. Life Time Achievement (North, East, West and South).
6. Best Centre.
7. Young Scientist.
8. Outstanding Prestressed Concrete Structure in the Country.
9. Best Student Chapter.
Last date for receipt of nominations is : 7th July 2011.
R.Radhakrishnan
Secretary General
ICI Update – May 2011 02
16th ICI (KBC) – Civil aid (Torsteel) Endowment
Lecture” was organized on 28th April 2011. Invited
speaker, Mr. Jose Kurian Chief Engineer, Delhi Tour-
ism & Transport Development Corporation, New
Delhi in his Endowment Lecture spoke on “Con-
struction of Underpasses under Restricted Bound-
ary Conditions”. The lecture brought out several
aspects of construction project in its entirety during
planning, analysis, design and construction Stages.
Four different construction projects,
Punjabi Bagh Grade Separator, Madhuban Chowk
Underpass, Prem Bari Underpass, Moolchand Un-
derpass within New Delhi limits were discussed.
Proximity to flowing canal, railway line, Metro line,
and flyovers compounded by high water table re-
sulting in enormous uplift posing severe constraints
in design, construction and choice of material were
presented. Lecture was highly
educative and informative.
Earlier Mr. Raj Pillai, Chairman, ICI -KBC welcomed
the gathering and briefed about the ICI-Torsteel En-
dowment Lecture. Dr. R. Nagendra, Technical Di-
rector Civil-Aid, co-ordinated the programme. Dr.
M. N. Hegde, Secretary, ICI - KBC proposed vote of
thanks.
Mr. Jose Kurian, C.E. DTTDC, Lighting the Lamp – Inauguration
Dr. C. S. Viswanatha Lighting the Lamp during Inauguration
Mr. Jose Kurian delivering the Endowment Lecture
Section of the Audience
News from Centres
ICI-Kar. Bengaluru Centre
ICI Update – May 2011 03
Dr. Manu Santhanam, Associate Professor, IIT Madras, Chennai delivering the Technical Lecture
Er. K. Jayasankar, Chairman, ICI – TNCC, Welcoming the participants
ICI Tamil Nadu Chennai Centre organized a Techni-
cal Lecture on Monday the 19th April 2011 at ICSR
Hall, IIT Madras. Dr. Manu Santhanam, Associate
Professor, IIT Madras spoke on ‘Water Proofing So-
lutions for Concrete Structures’
During his speech, he stressed upon the need to
have good quality of cover zone concrete as a strin-
gent security measure to tighten the entry of water
into the structure. He classified the water proofing
solutions as positive side/negative side, below/above
the ground/roof. He also differentiated between wa-
ter tight (read: damp proof) and water proof. He also
dwelled upon the various techniques of water proof-
ing solutions prevalent in the industry such as water
proofing compounds, damp proofing admixtures,
permeability resisting admixtures, crystalline water
proofers, chemical admixtures, grout materials, sur-
face treatment techniques – such as coatings, seal-
ants, penetrants (impregnates). He also cautioned
the listeners that the applications of the various wa-
ter proofing solutions deserve more merit else the
long term performance of the water proofing system
becomes questionable.
He concluded his speech by saying that though plen-
ty of systems are available for effective water proof-
ing treatments, nothing can substitute the good con-
struction and concreting practices.
This was followed by the sponsor’s presentation.
Mr. Atul V. Vaidya, Head – Business Development,
Construction Chemicals Division of M/s Pidilite
Industries Limited gave an elaborate presenta-
tion on their offerings for the various water proof-
ing treatments. Mr. Sanjiv Dutta, Chief – Industries
& Infrastructures was also present during the
occasion.
There was a greater interaction among the partici-
pants and the speakers. Initially, Mr. K. Jayasankar
Chairman of ICI TNCC welcomed the gathering and
Mr. K. G. K. Moorthy, Secretary & Treasurer of ICI
TNCC gave the vote of thanks
ICI-Tamil Nadu Chennai Centre
News from Centres
ICI Update – May 2011 04
Mr.Atul Vaidya, Head Business Development, Construction Chemicals Division, M/s. Pidilite
Industries Limited, Mumbai giving product presentation
Er.BRK Nair, GM (Projects), Gammon India Limited giving memento to Dr .Manu Santhanam, Associate Professor, IIT Madras, Chennai
Section of Audience
ICI Ghaziabad Centre
Two days National Conference on Repair and Re-
habilitation of Concrete Structures was organized
at NTPC Power Management Institute, Sector 16A,
Noida during May 6-7, 2011 by Indian Concrete In-
stitute, Western UP Centre Ghaziabad in association
with Indian Association of Structural Engineers and
Association of Structural Rehabilitation.
Mr. CS Prasad, Director General, Central Public
Works Department, New Delhi was the Chief Guest
of the Inaugural function. A revised reprint of CPWD
handbook on Repair and Rehabilitation of Concrete
Structures was also released by him during the Con-
ference.
This Conference was attended by more than 200 del-
egates/ authors/ manufacturers / exhibitors etc. from
various corners of the country. During the Confer-
ence, around seventy research papers on different
themes of the Conference such as Condition assess-
ment and Distress-diagnostic techniques; Causes of
distress; Repair and rehabilitation techniques; Ma-
terials for repair and rehabilitation; Durability, ser-
viceability and economy; New Techniques and Ma-
terials for Repair/ Rehabilitation and their life cycle
evaluation; Long-term health monitoring of struc-
tures; and Case studies were presented. Padmashree
Dr AS Arya; Prof DK Paul, IIT Roorkee; Prof K Ga-
nesh Babu, IIT Chennai; Dr GM Sabnis, USA; Dr SK
News from Centres
ICI Update – May 2011 05
Manjrekar, Mumbai; Dr. DG Kadkade, Noida; Prof
AK Tiwari, Mumbai and other eminent experts pre-
sented their papers and shared their views.
During the two day Conference, causes of dam-
ages and distresses in concrete structures, condi-
tion surveys, repair methods, repair materials, seis-
mic retrofitting of bridges and roads, fire damaged
structures, and health monitoring, along with case
studies were discussed in detail. Stress was given to
proper diagnosis of the structure to find out the root
cause(s) of the distress before carrying out repair
and rehabilitation work. Importance of selection of
proper repair material, repair method and availabil-
ity of skilled manpower was emphasized. It was sug-
gested that ITI should train masons, carpenters, bar-
benders etc. for this specialized field of Repair and
rehabilitation. It was felt that engineers should be
taught this subject in undergraduate degree course.
It was decided to formulate the recommendations of
the Conference to be sent to Govt. and other stake
holders for implementation.
Mr.AK Sharma, Chief Engineer, CDO, CPWD, New
Delhi and Dr.Rajeev Goel, Scientist, CRRI, New
Delhi were the Convener and Organising Secretary
of the Conference respectively. This is the first time
such a National Conference on this specialized topic
of Repair and Rehabilitation of Concrete Structures
was organised in this region.
Dr.Rajeev Goel
Honorary Secretary,
ICI-Ghaziabad Centre
Photo Gallery
News from Centres
Chief Guest Mr. C. S. Prasad, Director General,
CPWD, New Delhi lighting the lamp
Prof. A. K. Tiwari lighting the lamp. Mr. A. K. Sharma,
Dr. Rajeev Goel, Mr. P. C. Sharma, Mr. S. Ghosh and the
Chief Guest are watching
ICI Update – May 2011 06
News from Centres
AudienceEr. Vinay Gupta addressing the gathering
Dignitaries on the dias
Padmashree Dr. A. S Arya delivering his lecture Dr. Rajeev Goel welcoming the Guest
Mr. A. K. Sharma, Chief Engineer, CDO, CPWD, welcoming Mr. S. Ghosh
Selected Seminar Papers
Condition Assessment And Distress-Diagnostic TechniquesNational Conference on ‘Repair and Rehabilitation of Concrete Structures’ Organised by
Indian Concrete Institute, Western UP Ghaziabad Centre, during May 6,7, 2011 at NOIDA, INDIA
N S MoorthyDicoTech LLC, Concrete Repairs and Engineering, UAE Email: [email protected]
ABSTRACT
This paper discusses the critical requirement of the
correct condition assessment of concrete structures
and an open minded approach to assess the cause of
structural distresses and related symptoms. What is
visible to one is only the symptom. This will enable
identification of the problem in the first place. This
in turn will lead to the correct solution to the distress
of the structure. The diagnosis has to be based on
what is visible and duly correlated to the test reports
and what one perceives. There are many possible
causes that can cause a particular symptom and one
has to be methodical and logical in one’s approach
to narrow down the possibilities to arrive at the right
cause. This paper also shows some of the interesting
assessments that the author has made which do not
fall under the usual ones.
Condition Assessment
What is condition assessment? It is systematic and
logical examination of a structure to identify the
cause of the distress. The examination would cover
visual inspection, checking of documents; such as
drawings, construction records, previous investiga-
tion reports (if any), determination of the time of
appearance of the defect and analyzing the test re-
ports. Many times one would come across that many
of these may not be available! But still one has to
find ways and means of overcoming this.
Nature Of Distresses
Various kinds of distresses that we come across nor-
mally largely cover cracks (Fig.1) And the cracks
could be due to many reasons. Shrinkage cracks,
plastic shrinkage cracks, plastic settlement cracks,
early heat of hydration cracks, long term thermal
shrinkage cracks, excess stresses in flexure, tensile,
shear, punching etc. are the nature of cracks to name
a few. It could also be due to corrosion of reinforce-
ment or unequal foundation settlement.
Besides cracks, there are other symptoms of leak-
ages, seepages, discolouration and pigmentation of
concrete. i.e. stains on concrete could also lead to
important conclusions.
Fig.1 Cracks
Cracks
The first inspection to be carried out is the visual
inspection, which is the case for all the distresses ex-
plained.
Visual inspection
During visual inspection, the pattern of the crack
and the width of the cracks are to be documented
on floor plans of structure. This is called the crack
mapping. The crack mapping could be further en-
larged for better understanding for critical areas
by marking the grid both on the paper and on the
cracked structure and transfer the positions of the
cracks on to the paper. The width of the cracks is to
be measured using a crack width measuring gauge.
If both sides of the structure are accessible, it can
ICI Update – May 2011 07
be checked whether the cracks are through and
through. If it is not accessible, then ultrasonic tests
are conducted to determine the depth of the cracks.
GPR (Ground Penetration Radar) could also be used
for determining the depth of the cracks.
It is also important to decide whether the cracks are
active or dormant. A glass strip fixed across the crack
(Fig. 2) shall determine the status. If the glass is bro-
ken, then the crack is active, if not it is dormant.
Selected Seminar Papers
Fig.2 Instrument to measure the movement of crack
Cracks Remedies in brief
Let us look at the remedial measures.
1. If the cracks are at regular intervals, sometimes
even through and through, such as in a retaining
wall – inject the cracks using epoxy resin and pro-
vide control joints.
2. If the cracks are of irregular pattern such as shown
in Fig.1, it is most probably plastic shrinkage. A sim-
pler surface repair such as grouting will do (Fig.3).
3. If the cracks are wider at the top and extends only
up to the reinforcements, and mainly along the rein-
forcement then it could be due to plastic settlement.
Again grouting will do the job.
4. If it is early heat of hydration and long term ther-
mal cracks, the pattern would be the same as that of
item 1 and the treatment will be the same as well,
but with one important addition which is introduc-
tion of control joints.
5. If it is structural crack due to excessive stresses
then structural strengthening could have a number
of options including using carbon fibres.
Fig.3 Repaired Surface
6. The treatment for the cracks due to the corrosion
of reinforcement is dealt elsewhere in this paper.
But never an epoxy injection to such cracks. These
need a special treatment.
Leakage and Seepage
The second most common one is the leak (Fig.4).
Mainly in the roofs and many other water retaining
structures such as tanks, swimming pools, podiums,
dams etc.
Fig.4 Leakage of Water
Make sure that the ponded water, if any, is because
of the leaks. Sometimes this could be the water due
to washing of the floor!
Check whether it is coming through the cracks in a
clean line or else it is a damp patch. Many a times,
ICI Update – May 2011 08
it could be the construction/cold joint, which is the
weakest portion for such kind of leaks. Honeycombs
could be the reason for the damp patches. Check if
there are any expansion joints that could be leak-
ing. The formation of the salt crystals due to hon-
eycombing would give an indication of the duration
of the problem. Always touch to check whether the
seemingly obvious leaking points are still leaking. At
times it would have healed by itself.
Sometimes, it could be necessary to test the leaking
water to find out the source of leakage. It could be a
drinking water line or a sewage line that has burst or
could be the ground water.
Check the quality of the concrete by visual and ham-
mer sound testing. If the structure is of poor qual-
ity and honeycombed, the possibility of the leaks to
spring elsewhere, once the existing ones are closed,
is very high.
Leakage Remedies in brief
1. If it is a crack, normally pressure injection using
Polyurethane or Acrylic resins would solve the prob-
lem. When a construction joint is treated, make sure
that the entire lengths of the joint are treated even if
the water is coming selectively in portions.
2. If it is a damp patch and the concrete is generally
good, then the choice could be between pressure in-
jection or negative waterproofing using crystalline
technologies.
3. If the concrete is porous and not of a good qual-
ity and the possibility of water to leak through else-
where, then go in for crystalline treatment without
resorting to other polyurethane or other resins (fig
5). Once the concrete is contaminated with Polyure-
thane or other resins, it would be difficult to go in for
crystallization treatment to resolve the problem.
4. Treatment to an expansion joint is done by sealing
the joint with an acrylic or polyurethane resin (injec-
Selected Seminar Paperstion yes, but not necessarily a high pressure injec-
tion) to a depth of about 10 to 15 cm and the top of
the joint is resealed by using hypalon tape.
Fig.5 Crystalline will not work if contaminated with Polyurethane
Stains, Corrosion Cracks and Spalling of Concrete
Another common problem noticed is corrosion stains
on the concrete (Fig 6). The stains are the alarm bells
to indicate that reinforcement has started corroding.
The question would remain as to at what stage of
corrosion, it is.
Look for the size of the patch. Look for any steel or
other metal fixtures nearby which could have caused
the stain and not necessarily the reinforcement.
Look for any slight bulge around the satin, which
could have been caused by the expansion of the rust
in the reinforcement. This will show whether it is
nearer to spall the concrete.
Fig.6 Strains on surface
ICI Update – May 2011 09
Selected Seminar PapersHammer sounding test will show the delaminated
(but not spalled) areas, which is clear indication of
corrosion of reinforcement.
Measuring the extent of corrosion and its plotting on
floor plans is an important task to be done during
condition assessment. Half-cell potential test is the
most common one which indicates the extent and
the probability of corrosion.
Spalls
Then come the spalls (Fig.7). It is the splitting of con-
crete due the increase in volume of the reinforcing
steel because of an advanced stage of corrosion. The
corroded reinforcement gets exposed.
Visual inspection will show the extent of corrosion
spalling. In some cases one can find only the traces
of reinforcement as the reinforcement is lost due to
corrosion.
Cores are taken to determine the actual compressive
strength of the concrete and for assessment depth of
carbonation i.e. the depth of chemically deteriorated
concrete).
The powder samples of concrete are taken at vari-
ous depths by drilling to determine the chloride and
Sulphate profiles. Again this will be necessary to de-
termine the repair strategy.
Remedies in brief
• Identify the areas of corrosion stained delamina
ed and spalled concrete. Chip off the loose and de-
teriorated concrete. The chipping shall continue to
25mm behind the reinforcement and 50mm beyond
the sign of corrosion. Care shall be taken to cut the
edges of repair by at least 5mm to avoid feather edg-
ing when the re-profilation is done.
• Grit blast the corroded reinforcement to near
white metal condition.
• Apply neat polymer modified cement slurry over
the reinforcement to protect from the onslaught of
elements.
• Make sure sacrificial anodes are fixed on the re-
inforcement such as Galvashield, to avoid incipient
anodic effect.
• Soak the concrete surface to a fully saturated but
no standing water condition.
• Carryout the repair and make up the area with
micro concreting or shotcreting for the reprofilation.
The curing is a must even it is for a limited number
of days.
CASE STUDY 1: ECCENTRIC LOADING ON
THE CORBELS
This was a precast framed structure for a shopping
mall in the Middle Eat. The precast elements of col-
umns and beams with facias were designed, pro-
duced and erected by an internationally renowned
firm. The columns were erected and the beams were
placed in position on the corbels. The problem start-
ed when the structure was loaded with the façade
panels. Almost all the corbels cracked (Fig.8) and the
construction was stopped.
The visual inspection showed that the cracks have
opened at the top and narrowed as it went further
down. So it is a crack caused due to flexure on the
corbel. The load transmission was by a kind of point
load through the shims kept in position to adjust the
levels during erection. The point of transmission of
Fig.7 Spall of Concrete
ICI Update – May 2011 10
load appeared to be more towards the edge of the
corbel. So, this was an error of erection. But that was
not the only error that happened. When the precast
elements were produced in the factory, a steel plate
was embedded in the corbel to indicate the erection
crew, the locations of the leveling shim for the beam.
The placement of the beams was wrong. So the pro-
duction could be wrong. But not really. The produc-
tion follows a shop drawing which indicates clearly
where the embed had to be placed. The original mis-
take has happened with the draftsman who had put
in a wrong dimension.
Remedy
The owner wanted the structure to be rebuilt by the
contracting company as he did not want to take any
chances with the safety of the public who would be
using the shopping mall. The contractor was reluc-
tant to go in for reconstruction. So a solution had to
be found out.
The beams were slightly jacked up to relieve the cor-
bels from the loads. The existing cracks have been
sealed by pressure injection. The joint between the
corbels and the beams were sealed. An epoxy resin
with 100% solids was injected at low pressures to
create a solid and uniform bed to distribute the load
over a large area. Once the epoxy resin was cured,
the beams after its structural retrofitting and shift-
ing the loading point to safer turfs, were allowed to
rest. The structure is still standing after 20 years of
this operation.
Fig.8 Repair of cracked corbels
CASE STUDY 2: CRACKS IN THE PEDESTALS
OF FLUE TUBE
It is a case of a power generating station. The tur-
bines were seated on heavy foundation pedestals.
The flue tube which was about a meter dia was also
resting on two pedestal foundations. The power sta-
tion was stopped after 100hors of commissioning due
to cracks developed on the flue tube pedestals and
also the grout bedding under the foundation plate
had turned black. Despite re-doing the grouting and
injecting the crack, the problems again resurfaced
after running the turbines for another 100 hours or
so. That was when the problem was referred. The
second problem of grout bleeding under foundation
plate was easier to identify. An epoxy grout had been
used under the base plates. But the epoxy grout had
a limitation of higher temperatures more than 70c.
The flue gas temperatures which can reach sever-
al multiples of this have obviously burnt the epoxy
grout. It was suggested that a cementitious grout of
high compressive strength shall be used instead of
an epoxy grout. But the cracks on the pedestals were
a bit challenging. The cracks have started at the an-
chor bolt points and wider at the top and narrower as
it went down. So it was the lateral pressure exerted
on the anchor bolts that could have been the reason.
This pressure could come only from the movement
of the flue tube. But it is designed for movement.
There are two base plates one on top of each other.
The top plate is rigidly fixed to the flue tube while
the bottom one is fixed to the pedestal. The interface
between the plates is to be greased to facilitate the
movement. It was out in the site that it was not so
and grease port was even blocked. Hence, it was ad-
vised that the ports are greased periodically and the
repairs for the cracks were carried out.
Fig.9 Schematic layout
Selected Seminar Papers
ICI Update – May 2011 11
CASE STUDY 3: LEAKAGE IN BOMB SHELTER
Bomb shelters are structures where the fighter
planes are parked for protection against the debris
due to bombs and its explosion. The structure is
parabolic with 50cm of sand encased by concrete
on both sides. The thickness of the concrete casing
was 1m external and 50cm internal (Fig.10) There
was water leaking through the expansion joints like
coming out of a tap. So the first checking to be done
was all the plumbing lines. But the lines showed no
drop in pressure which showed that the plumbing
was not the reason.
The roof had an expansion joint which was sealed
by a polysulphide mastic sealant. The joint width
was about 10cm (!) as against the 20mm designed
(Fig.11).
The polysulphide sealant had given way and in many
places come off the sides of the concrete. Whenev-
er there had been rain in that area, the rain water
has gone in and collected in the voids of the sand
cushion in-between the concrete casings. Even after
3 months after the rain has stopped, the collected
water was coming out of the expansion joints by the
sides. The collected water around the bunker has
caused heightened ambient relative humidity. This
in turn and in course of time started the corrosion
of the reinforcement. The concrete started splitting
and the bomb shelter faced the bleak prospect of
falling apart without bombs (Fig.12).
The only remedy was sealing of the expansion joints
on the top, but this time using a hypalon tape system
which is suitable for higher joint widths. The expan-
sion joints at the sides were injected with polyure-
thane resin to stop the water and the joints sealed
with hypalon tape system.
CASE STUDY 4: LEAKAGE THROUGH JOINTS
This was a discharge channel in the process area in a
petrochemical plant. The discharge was a combina-
tion of EDC (Ethelene di Chloride) and Hydrochlo-
ric acid. The discharge had started leaking through
the damaged joint sealants (Fig.13) and into the soil.
There was a pump and compressor area nearby. The
EDC which has gone into the soil had eaten away the
construction fillings under the pump foundations
and the area started to settle down. The situation
was alarming and it might cause the shutdown of the
plant. The existing sealant was good enough to resist
the combination of this chemical. But it was not elas-
tic enough to resist the movements of the channel.
The expansion joints have given way and hence the
leakage. The requirement of the client was a seal-
ant that shall resist 100% concentrated EDC and a
15% concentration of HCL both combined at a tem-
Selected Seminar Papers
Fig.10 Schematic View of Bomb Shelter
Fig.11 Schematic View of failed expansion joint
Fig.12 Schematic View of damaged concrete
ICI Update – May 2011 12
perature of 100oC. The material suitable to resist
EDC, would not resist HCL and vice versa. Even
with a material able to resist both then, the tem-
perature was a problem. If all these conditions were
satisfied then it was not flexible enough which could
Selected Seminar Papersbe laid in the channel to remain in good shape.
The finding and the subsequent thought pro-
cess made the team to invent a joint sealant using
non-elastomeric HDPE to take the expansion and
contraction and also to not to give way.
Fig.13 Schematic View of Channel and failed expansion joints
CASE STUDY 5: CRACKS IN CAR PARK
The car park was of 4 levels and the main contrac-
tor was in the process of handing over. But was not
able to, because there were cracks developed in the
ramps (Fig.14). When checked, something peculiar
was noticed. The cracks were in the ramps in a kind
of regular intervals. But the ramps in the opposite
side of the car park floor did not have any crack! All
these were done by the same company and at the
same time.
Fig.14 Schematic view of Cracked Locations
But why on one and why not on the other? One
side of the car park had a mosque, which was of low
height and plenty of space around. But on the other
side there were high rise buildings. The Sun was
shining on the car park on the mosque side and was
shaded constantly on the other side. The result: the
ramp on the mosque side was subjected to height-
ened temperature variations, whereas the other side
was relatively stable.
Having solved the puzzle, the remedy given was to
inject the cracks with rigid epoxy resins but cutting
out control joints to take care of the movements.
CONCLUSIONS
An assessor would find that many times the cause
of distress could be found by methodical and logical
derivations. But some times what one sees and as-
sumes is not what it is. That was why an emphasis
has been made to keep an open mind when one goes
for a condition survey. It is always good to remem-
ber not only to look at the structure but look its sur-
roundings. One has to look for the basic reasons that
might have caused the distress. Such as when a roof
is leaking, just unblock the drains. This will save the
problem of roof leakage and save lot of money to the
owner.
ICI Update – May 2011 13
ABSTRACT
In the modern era, fire is one of the unpredictable,
but common causes of accidental damage of indus-
trial structures. Reinforced concrete Structures
though less susceptible to structural damage to an
extent of Steel Structures are also damaged and may
require large repairs depending upon the duration
of fire and temperatures attained during the same.
The investigation to assess the damage to concrete
and steel members is tedious and requires addition-
al help of concrete petrographers. A combination of
non-destructive test tools along with chemical and
micro structural investigation is required to assess
the damage to structural elements before preparing
the repairrehabilitation programme for the struc-
ture. The papers details the methodology adopted
for investigation, assessment of structural health
and reliability of various test for investigation of a
fire damaged structure.
Keywords: fire, temperature, petrographers, micro-
structural
INTRODUCTION
When reinforced concrete is subjected to high tem-
perature as in fire, there is deterioration in its prop-
erties. Of particular importance are losses in com-
pressive strength, cracking and spalling of concrete,
destruction of the bond between the cement paste
and the aggregates and the gradual deterioration of
the hardened cement paste.
Assessment of fire-damaged concrete usually starts
with visual observation of color change, cracking
and spalling of the surface. Concrete color provides
a broad, general guide of temperatures, whether the
color represents the original surface or one result-
ing from spalling. Crazing, cracking popouts caused
by quartz or chert aggregate particles, spalling and
dehydration (crumbling and powdering of paste) are
general indications of temperatures to which con-
crete has been exposed as shown in Fig.1. On heating
above 300 °C the color of concrete can change from
normal to pink (300–600 °C) to whitish gray (600–900
°C) and buff (900–1000 °C). The pink discoloration re-
sults from the presence of iron compound in the fine
or coarse aggregates [1, 2 and 3].
The first effects of a slow temperature rise in con-
crete will occur between 100 and 200 °C when evapo-
ration of the free moisture, contained in the concrete
mass, occurs. Instant exposure can result in spall-
ing through generation of high internal steam pres-
sures. As the temperature approaches 250 °C dehy-
dration or loss of the non-evaporable water or water
of hydration, begins to take place. The first sizable
degradation in compressive strength is usually expe-
rienced between 200 and 250 °C. At 300 °C strength
reduction would be in the range of 15–40%. At 550 °C
reduction in compressive strength would typically
range from 55% to 70% of its original value [3, 4 and
5].
Selected Seminar Papers
Diagnosis of Fire Damaged Industrial StructureNational Conference on ‘Repair and Rehabilitation of Concrete Structures’ Organised by
Indian Concrete Institute, Western UP Ghaziabad Centre, during May 6,7, 2011 at NOIDA, INDIA
Ashok Kumar TiwariVice President ( North) Indian Concrete Institute
Email: [email protected]
Fig.1 Visual evidence of temperature to which concrete has been heated
ICI Update – May 2011 14
Selected Seminar PapersTemperatures in the 550 °C range are critical because
calcium hydroxide dehydration takes place. Calcium
hydroxide is a hydration product of most Portland
cement, the amount being dependent upon the par-
ticular cement being used. Aggregates also begin to
deteriorate at about 550 °C. For example quartz ex-
pands at a higher rate around 300 °C [6 and 7].
Two main types of spalling occur during fire. Explo-
sive spalling and sloughing off of concrete surface
layers. Explosive spalling looks like a series of pop-
outs and usually occurs within the first 30 min of
fire-exposure. Sloughing off is a gradual non-violent
separation of the concrete that occurs primarily at
the edges of columns and beams. When concrete
spalls, deeper layers of concrete are exposed to the
maximum fire-temperature, speeding the transmis-
sion of heat to the reinforcement. As the temperature
within a member rises, steel reinforcement expands
more than concrete. This can lead to further spalling
and cracking around the steel. Such cracks often de-
velop where incipient cracks (due to drying shrink-
age, flexural loading or other factors) were present.
Also, differing thermal expansion between aggre-
gates and cement paste can create surface crazing,
which can lead to deeper cracking [4 and 7].
INDUSTRIAL BUILDING-CASE STUDY
The building constructed is a composite structure
consisting of RCC frame, a steel column and some
external load bearing walls housing R & D centre
and office space. It is reported that the building
was earlier used as industrial building and only few
years ago, it was converted to office cum R & D
building. The structural layout of the building is
bit complex and seems a number of extensions to
building were affected since its inception. The
external columns are spaced at 3.3 m span and
longest beam spans to 8.5 m. There are four slabs
in office area and two in R & D area. The structure
was constructed in 1965 and none of the structural
drawings are available.
It is learnt that the structure caught fire after office
hours at about 7.30 PM on Friday, March 22, 2002.
The fire was brought under control by around 2.30
AM in night.
Investigation For Fire Damage
A detailed visual inspection of the building and the
following Non-destructive tests (NDT) at
select locations were carried out to assess the extent
of fire damage on building RCC structure.
The results of NDT are provided in the form of ta-
bles.
• Schmidt Hammer test
• Ultra-sonic Pulse Velocity (UPV)
Also, concrete core samples, concrete chunks and
reinforcement bars were collected from different lo-
cations and were analyzed for the following at labo-
ratories;
• Compressive strength tests
• Chemical properties like pH, Chlorides and
Sul phate
• Differential thermal analysis
• X-ray diffraction
• Yield strength, weight loss and elongation of
rebars
Visual Inspection
The building was visually inspected and a structural
layout of building was prepared, as
shown in Fig.2. The following are the main observa-
tions of the Visual Inspection Survey:
1. The concrete elements viz., columns, beams and
slabs are severely affected by fire on some of the
floors.
2. The damage due to fire on ground floor is almost
negligible excepting discolorations of surfaces
due to smoke.
3. Most of the structural elements, in office area
were severely damaged due to fire showing
spalling, cracking at the surface of elements.
ICI Update – May 2011 15
Selected Seminar Papers4. The damage due to fire on IV floor seems to be
ngligible except discolorations of surfaces due to
smoke.
5. Severe damage of many columns and slab bo
toms of first, second and third floor due to
fire was observed in the form of cracking,
spalling, and colour of concrete turning to whi
ish brown.
6. Deflection of longest span beams at all three
floors were measured to find the effect of fire
on steel reinforcements. The measured defle
tions are given in Table 1.
Fig.2 TGA scan for First floor Column A5, depth 100 mm
Non-destructive test results
Impact Hammer Test
The Schmidt hammer test was done at select loca-
tions of the building and results were found to be
highly variable due to surface condition. The test
was discarded for the present evaluation, as rebound
hammer tends to give higher values for carbonated
surfaces and variations are high.
Ultra-sonic Pulse Velocity Test
The ultra-sonic pulse velocity measurements were
taken at select locations of the building to see the
soundness of concrete on unaffected elements /por-
tions and also on fire affected elements. The results
are provided in Table 2. The criteria for qualitative
assessment of the concrete quality is based on ARE
code. The results reveal that the ultra-sonic pulse
velocity more than 3.5 km/sec taken at undamaged
areas indicates good quality of concrete. The very
poor velocities or no sound wave transmission at fire
damaged locations could be due to cracks and/or sig-
nificant damage of concrete.
ICI Update – May 2011 16
Selected Seminar Papers
Core Test
The concrete cores were extracted from select loca-
tions of the building from damaged and undamaged
concrete elements. Please note that cores were bro-
ken during extraction up to 100 mm from surface in
the fire damaged concrete elements. It clearly shows
that severe damage due to fire has occurred. The
cores collected from undamaged concrete elements
were tested at the RCD laboratory in Thane. The re-
sults of core test are tabulated in Table 3.
The results reveal that the concrete strengths
obtained from core testing are satisfactory for M15
grade (1:2:4) concrete used in the construction.
Test on Rebar samples
The Reinforcement bars were collected from select
fire damaged RCC members of the building and
were tested for strength, weight loss and elongation.
The results are tabulated in Table 4. The results with
respect to IS code are unsatisfactory.
Analysis of concrete
Chemical analysis
The chemical analysis of the concrete samples, for
Chloride content, Sulphate content and pH of con-
crete, prepared from the concrete cores collected
from select locations of the structure was carried
out. The identification of sample taken for chemi-
cal analysis and the results are provided in Table 5.
Chloride content in all samples is lower than the lim-
iting value of 0.4%. Sulphate content of all samples is
also less than the limiting value of 3%.
The pH value is below 10.5 in all cases of samples
tested indicating that the alkalinity of the concrete
has gone down in concrete. The pH values less than
10 shows high degree of loss in Ca(OH)2 due to fire
even up to a depth of 100 mm from the surface of
concrete.
Differential Thermal Analysis (DTA) &
Thermo-gravimetric Analysis (TGA)
DTA and TGA techniques are employed for the
qualitative and quantitative estimation of the com-
pounds present in the concrete samples. The tech-
nique involves heating up of the sample under con-
sideration and thermal behaviour is observed which
is related to the identification of compounds actually
present and comparing with similar sample which is
not subjected to fire. The Differential thermogram
of concrete sample exhibits endothermic peaks in
different temperature ranges and these ranges are
generally attributed to certain parameters as given
in Table 6 below:
ICI Update – May 2011 17
Selected Seminar Papers
Selected samples taken from cores and concrete
chunks have been subjected to DTA/TGA to study
the thermal behaviour of concrete. A few typical
scan of DTA and TGA are given in Fig.2 and Fig.3.
The results reveal that many samples taken at vary-
ing depths up to about 100 mm from surface show
low or zero weight loss. It can be said that these sam-
ples taken from the severely damaged members are
already exposed to temperature more than about
5000C and concrete has lost most of its strength. In
addition the passivity of concrete to rebars against
corrosion is almost completely lost in the absence of
Ca(OH)2.
Fig.3 TGA scan for Second floor Column E5, depth 100 mm
X-Ray Diffraction (XRD)
In the XRD technique, the characteristic diffraction
lines of each micro-crystalline cementitious phases
and their hydration / degradation products are com-
pared with the standard mineral phase samples and
the degree of variation in terms of intensity, shape
and position of these lines is considered for identifi-
cation /evaluation purpose.
Selected samples prepared from cores and concrete
chunks have been subjected to XRD analysis. The
presence of Calcium hydroxide (Ca(OH)2) found
from XRD analysis in the form of counts is given in
Table 7. The results are supportive to DTA. A few
scans are shown in Fig.4 to Fig.7.
Fig.4 XRD scan sample from Second floor Column E5, depth 100 mm
Fig.5 XRD scan of sample from first floor column G2
Fig.6 XRD scan of sample from first floor beam 5-5
ICI Update – May 2011 18
Selected Seminar Papers
Fig.7 XRD scan sample from First floor Column A5, depth 100 mm
CONCLUSIONS
The following observations are made in the evalua-
tion of the building:
1. Building is about forty years old and reinforc
ments are heavily corroded, lost cross-sections
and fails in ultimate tensile strength specific
tions. All the reinforced bars tested are found to
be unsatisfactory.
2. Fire has penetrated into concrete beyond the
cover to rebars, reaching the core of most of the
columns.
3. Due to loss of Ca(OH)2 from concrete cover, con-
crete will no longer be able to protect rebars from
corrosion.
4. The concrete has become brittle and quality is
unsatisfactory even though some cores show sat-
isfactory strength levels.
5. In R & D building, main beam seems to be resting
on end steel column, which must have lost its ten
sile strength heavily.
RECOMMENDATIONS
Based on the investigation, it is recommended here
that all floors of building, except ground floor shall
be dismantled.
ACKNOWLEDGMENTS
The reported case study has been a consultancy proj-
ect by the author in capacity as Head of Concrete
Technology Group at ACC Limited. The acknowl-
edgement is due to the management and working
group at the company along with manag ment of Ex-
cel Industries, Mumbai.
REFERENCES
1. B. Erlin et al., Evaluating fire damage to concrete
structures. Concrete Construction 2 (1972),
pp. 76–82.
2. J.K. Green, Reinstatement of concrete structures
after fire. The Architects’ J 1 (1971), pp. 93–99.
3. Guise SE. Petrographic and color analysis for a
sessment of fire damaged concrete. In: Jany L,
et al., editor. Proceedings of the 19th International
Conference on Cement Microscopy. 1999. p.
365–72.
4. L. Powers-Couche, Fire damaged concrete-up
close. Concrete Repair Digest 1 (1992), pp.
241–248.
5. Gustafero AH. Experiences from evaluating fire
damaged concrete structures––fire safety of con-
crete structures. American Concrete Institute
SP-80, 1983.
6. Chu TY. Radiant heat evaluation of concrete––a
study of the erosion of concrete due to surface
heating. Research Paper Sand 77-0922. Sandia
Laboratories. Albuquerque Nm, 1978.
7. Powers-Couche L. observations of concrete e
posed to very high temperature. In: Gouda Gr. et
al, Editor. Proceedings of the 16th International
conference on cement microscopy. 1994. P.
369–76.
8. Georgali, B. and Tsakiridis, P. E., Microstructure
of fire-damaged concrete. A case study , Cement
and concrete composites Volume 27, Issue 2 , Feb-
ruary 2005, Pages 255-259.
9. Tiwari, A. K., Structural assessment and repair
of fire affected buildings, The International Con-
ference on Concrete Repair, Rehabilitation and
Retrofitting, Cape Town, South Africa, November
2005.
10. Concrete Society, Assessment, Design and R
pair of Fire–damaged Concrete Structures, Tec
nical Report No. 68, December 2008.
ICI Update – May 2011 19
ICI Update – May 2011 20
MBM Engineering College, Jodhpur
MBM Engineering College, Jodhpur organized
a three day symposium “ADCON 2011” between
28th and 30th April 2011. It was a National Level
Deminar on ‘Future Sustainable Concrete” with a
talent inquest for civil engineering students. Manu-
facturers demonstrated their latest product during
this event. Prof. S. S. Sankha was the Adviser and
Mahipal Burdak was the co-ordinator for the whole
programme. The first day key-note address was
delivered by Er.Prakash Sharma on ‘Correct Step
for Concrete Making’. On the second day of the
Deminar there was a competition in paper
presentation for students in which Charu Mittal was
the winner. This was followed by a quiz competition
in which teams of Prem Kumar and Sukhdeep Singh
were declared as winners.
Students took a site visit to a sewage treatment plant
at Salawas and Dr. S. K. Singh guided the tour. They
also visited AIIMS Jodhpur Hospital construction
site, a concrete testing laboratory and a batching
plant at the construction site. Prof. P. K. Agarwal
RTU Kota briefed on the High Performance Con-
crete and Self Compacting Concrete.
On the last day, Prof.Agarwal spoke on Use of Fly
Ash, its Microstructure and other mechanical and
chemical properties in making the concrete. Prof.
Bupendra Singh, IIT Roorkee presented a case study
on DMRC Project Pier Failure. Prof. A. K.Gupta
discussed on ‘Field Failure Reasons’ and stressed
on the Importance of Workability and Workman-
ship. Prof.B.Singh presented a case study on ‘JLN
Stadium’ and ‘CWG Foot Bridge Failure’. Er. Rajesh
Kumar, Zonal Head, Ultra Tech Concrete shared
his views on RMC and Value Added Concrete and
explained the importance of safety at Construction
Site.
Lectures, Video Presentations, Demonstration of
Equipments, Site Visits and Talent Quests were the
highlights of the event which was informative and
interactive.
Opening ceremony of ADCON 2011 Chief Guest Prof. Dr. Naveen Mathur &
other participant
ICI Students Chapter
ICI Update – May 2011 21
ICI Students Chapter
Lecture by Er. Prakesh Sharma Er. M. Khursid and Er. R. Ganeshan explaing to students.
Site Visit guided by Dr. S. K. Singh
Prof. S. S. Sankhla guiding the students
Students participating in Talent Quest
Lecture by Prof. P. K. Agarwal
ICI Update – May 2011 22
ICI Students Chapter
Lecture by Prof. Bhupendra Singh Lecture by Er. Rajeeb Kumar
Organisers with Chief Guest at valedictory function.
Tariff For advertisement
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ICI Update – May 2011 23
1. Inauguration of New ICI Students Chapter
1. ICI Student Chapter of Global
Academy
ICI-Student Chapter-Global Acade-
my of Technology was inaugurated on
Thursday 28th April 2011 by Mr.Vijay
R.Kulkarni, President ICI in the pres-
ence of Dr .C. S. Viswanatha, Chairman,
CTPL. & Chairman, Taskforce for Qual-
ity Control, Bangalore.
Mr. Vijay R. Kulkarni, in his inaugural
address, provided full information on
present state of construction industry in
the country and the associated umpteen
opportunities which are available for
Civil Engineers.
Mr. Rajkumar Pillai, Chairman, ICI,
Karnataka Bangalore Centre spoke on
the importance of integrity and hands-
on experience as mandatory ingredients
for young engineers for the success in
any profession.
Mr. M. S. Sudarshan, Vice Chairman,
Civilaid Technoclinic (Pvt) Ltd. stressed
upon the need for Industry Institute In-
teraction and explained the efforts on
the part of CTPL to bridge industry and
academia for mutual benefit and society
wellbeing.
Dr. Narendra Viswanath, Principal, Glob-
al Academy of Technology welcomed the
gathering. The programme was success-
fully organised by the students under
the leadership of student Coordinators
Pramod. M., Amey Gudigar and Pavan P.
of VI Sem. Civil Engineering under the
guidance of Dr.C.V.Srinivasa, Professor
and Head, Department of Civil Engi-
neering, and Bharathi Ganesh, Assistant
Professor, ICI Coordinator, GAT.
Inauguration of GAT-ICI Student Chapter
Dr. M. R. Kalgal giving away the Certificate of Merit to students
Dignitaries during the Student Chapter Inauguration
ICI Students Chapter
2. SRM University, NCR Campus, Modinagar
Student Chapter of SRM University, NCR Campus,
Modinagar was inaugurated on 8th May 2011.
Prof.K.S.Raja, Asst. Professor welcomed the gather-
ing. Prof.A.K.Tiwari, delivered a lecture on “Various
Aspect of Civil Engineering”. Following this office
bearers of the Student Chapter were introduced.
Dr. Gajanan M. Sabnis alongwith Dean, SRM Uni. and Prof. A. K. Tiwari lighting lamp
Dignatries alongwith students and faculty of SRM University
Prof. A. K. Tiwari receiving bouquet from Dr. Vineet Bajaj, H.O.D., Deptt of Civil Engg.
On this occasion, Dr.Gajanan M.Sabnis who was the
Chief Guest, gave a special lecture on ‘Green Con-
crete’.
The programme ended with vote of thanks by Prof.
M. K. Pandey, Dean, SRM University.
Office-bearers of the student chapter
ICI Update – May 2011 24
ICI Students Chapter
ICI Update – May 2011 25
Forthcoming Events ICI-Pune centre is Organising a seminar under the banner of CEMCON 2011 on “Construction of Highrise
Building (Above 100 M)” on 17th and 18th June 2011.
For details, pl contact :
CEMCON 2011, c/o Arkey Engineering, Prabhat Road, Pune 4. Tel : 91-20-25670808, Fax: 91-20-25672555,
25676767. Email: [email protected], [email protected].
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