Condition Assessment and Evaluation of Concrete Structures by Advanced Non-destructive Methods

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
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Condition Assessment and Evaluation of Concrete Structures by
Advanced Non-destructive Methods
Syed Azhar Uddin1, Khaja Omer Uddin2, Shaik Mohd Ibrahim3, Kanchala Nanchari 4
1, 2, 3 UG Students, Department of Civil Engineering 4 HOD Dept of Civil Engineering
ISL Engineering College, Hyderabad, Telangana, India
---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract - Structures built in India throughout the early
1970s and late 1980s are found to be in bad condition due to
weak specifications and poor building procedures. Continuous
monitoring of concrete structures using appropriate NDT
(Non Destructive Testing) technologies and the use of feasible
restoration procedures aid in a significantdecreaseintherate
of degradation of concrete structures, extending their life
lifetime. In analysing the uniformity, homogeneity,
approximate compressive strength, durability, the level of
rebar corrosion in concrete, and other properties of damaged
buildings, NDT technologies have a significant benefit. The
goal of this research is to extend the life of a 50-year-old
commercial structure in Hyderabad (partly RC and brick
masonry). The findings of the condition evaluations are
reported in this publication, which include a visual, field, and
laboratory examination of samples gathered from the
structure. The document also discusses how to measure the
strength and durability of concrete in order to determine the
amount of the building's distress and damage. Aside from
visual inspection, nondestructive evaluations such asUPVand
Rebound Hammer values, Half Cell Potential, and chemical
tests on chosen undamaged RC columns, beams, and slabs are
also shown and discussed. To extend the life of the structure,
repair and strengthening procedures employing the most up-
to-date materials, as well as feasiblerestorationworkssuchas
column jacketing, shotcreting, anticorrosive coatings, and so
on, have been recommended.
Key Words: (NDT Methods; Condition Assessment; repair
and strengthening
1. INTRODUCTION
Globally, concrete is one of the most versatile and
commonly utilised construction materials. Reinforced
concrete buildings must survive environmental conditions
for the duration of their lives if they are correctly
constructed and installed. It is exemplified by the vast
number of concrete structures constructed during the last
century in various regions of the world.
As a ferrous substance, steel implanted in concrete
structures, whether as reinforcementorprestressedtendon,
is prone to corrosion, which cannot be completely
eradicated. In the 1970s and 1980s,all industrialisednations
implemented required preventative measures, including
revisions to concrete regulations to incorporateappropriate
durability practises. However, in India,thisprocesshasbeen
extremely sluggish; even the fundamental concrete code IS:
456-2000 has not been fully revised to meet durability
requirements. Our infrastructure is heavily reliant on steel
reinforced concrete structures. The combination of
concrete's strong compression strength and reinforcing
steel's high tensile characteristics results in an excellent
composite material that, in comparison to other materials,
has a broader variety of structural engineering applications.
Steel reinforced concrete is used to construct buildings,
slabs, beams, bridge decks, piles, tanks, and pipelines.
Corrosion is the degradation of material as a result of its
interaction with the environment. Among the different
corrosion factors, the most prevalent is air corrosion, which
results in steel rusting. Corrosion becomes noticeable when
the air's relative humidity hitsroughly65percent.Corrosion
is impossible in dry, clean air and waterwitha freezingpoint
below zero. Thus, structural health monitoring is critical for
determining the extent of deterioration over time. Non-
destructive testing (NDT) is a critical component of a
comprehensive structural health monitoring system. NDT
techniques aid in determining the quality and homogeneity
of materials without impairing the structure's performance
or serviceability during their examination. Failures in
reinforced concrete buildings can be avoided by corrosion
monitoring and early identification of cracks utilising a
variety of nondestructive testing (NDT) technologies.
Numerous assessment techniques are now employed to
obtain data on structural performance metrics such as
displacements, strains, and stresses. This data is paired with
powerful post-processing methods to derive information
about the present operating status and remaining life of the
component. The NDT method selected is determined on the
property of the concrete being analysed, such as strength,
corrosion resistance, and crack monitoring. Corrosion of
Reinforcement is influenced by the following factors:
• Concrete Quality
• Concrete Cover Thickness Over Reinforcement
• Reinforcement Condition
• Environmental and other Chemical Effects
• Concrete Porosity
• The Impact of High Thermal Stresses
• Freezing and thawing temperatures
• Total Steel Loss Due to Corrosion
• Reinforcement Steel Storage and Stacking

Structural elements that havebeendamaged,misaligned,
hit, or have lost concrete or steel sectionsneedtobechecked
out before they can be repaired for corrosion. Thisiscalleda
condition evaluation. These things could happen, and they
could make it hard for the concrete to get stronger after the
repair. Degradation processes that may lead to corrosion of
the reinforcement (freeze-thaw,sulphateattack,etc.)should
also be taken into account.
Different parts of the structure should be separatedintotwo
groups: a) Reinforcement is not corroding yet, because
carbonation or chloride penetration has not reached the
steel surface. b) Reinforcement is corroding, but the spread
of the corrosion is still very small, because the concrete
cover is not cracked and the reduction in cross section of
rebars is very small. c) Corrosion of steel can cause the
concrete cover to crack, split or delaminate, or the rebar to
lose more than a small amount of its cross section. This can
make the structure less useful.
The main focus of the paper is the condition of a 35-year-
old commercial building and the possible rehabilitation
works that could make it last longer and be more safe. The
first step in determining the condition of a structure is to
look at it. This includes probing cracks and spalls to see how
far they go, measuring reinforcement cover, and so on.
Possible strength measurements, carbonation
measurements, and electrode measurements are done by
taking samples for lab tests in the second phase. NDT
methods have been combined to look at how well structures
are made, and possible repair and restoration projects have
been suggested.
2. LITERATURE REVIEW
A large number of studies have been carried out all over
the globe to examine the degradation of existing concrete
buildings. When it comes to analysing such structures, non-
destructive approaches are quite significant. A large number
of writers from across the world presented their researchon
non-destructive evaluation techniques and probable
strengthening strategies that may become accessible from
time to time for aged and degraded structures in various
locations.
Gattulli and Chiaramonte [27] used the visual inspection
method for the quality determination of a bridge for Italy
railways. They conducted inspections on concrete, steel and
masonry bridges. The damage levels associated with
maintenance and repair was discussed. Four different
simulation models have been proposed for the regular
assessment of these structures. Abdulkader El Mir et al. [9]
emphases on the limitations of rebound hammer method
based on the responseofthereboundindextowardsdifferent
parameters. The author conducts a series of experimental
tests on 795cubic specimensto understand therepeatability
of the rebound index in several concrete type admixtures.
The surface hardness test is conducted using the N-type
Schmidt hammer according to European standard. The
results of his experiment discussed on the parameters such
as water binder ratio, the water-powder ratio, SCMs and
admixtures. His experiments proved that the coefficient of
variation of the rebound index has influence on the
parameters such as water binder ratio, the water-powder
ratio, SCMs and admixtures of the concrete cubes tested. Jin-
Keun Kim et al. [10] determines the strength parameters of
concrete and factors affecting the Rebound Number due to
carbonation in concrete structures with his experiments. He
has established relationships between the Compressive
Strength for 28, 90, 180, and 360 days concrete cubes
respectively and the Rebound Number. A new equation was
derived considering the effect ofcarbonationontheRebound
Number in determining the strength reduction coefficient.
Abdulkader El Mir et al. [17]hasconductedinvestigations
to evaluate the compressive strength of concrete and
boundary imitation of Rebound Number using Rebound
Hammer equipment. Results showed that, from normally
vibrated concrete to Ultra-High Strength concrete and the
water powder ratio, the water-binder ratio, and the
admixtures relatively has influence on the rebound index
number and compressive strengths. Ourania Tsioulou et al.
[11] studies shows, the evaluation of tensile strength andthe
Compressive strength using UPV and Rebound Hammer
measurements. Author uses the combination of methods in
his analysis. He concluded that the combined use of these
methods offers higher accuracywheretesterrorswerefound
to be below 10% in the determination of compressive
strength and modulus of Elasticity. M. Yaqub et al. [12] has
conducted experiments to determine the compressive
strength in the existing RC columns damaged in a fire
accident using UPVTestMethod.Hisexperimentsshowedthe
variationincompressionstrengthofconcretewhensubjected
to different temperature conditions. Maitham Alwash et al.
[16] discuss the techniques like rebound hammer and the
Ultra-Sonic Pulse Velocity test. The factors affecting these
techniquesandmeasurestodevelopeffectivemethodologyin
improving strength parameters using synthetic simulation
approach has been proposed. Veerachai Leelalerkiet et al.
[13] has used Half-Cell Potential apparatus to determine the
probability of rusting of steel in reinforced concrete slabs
subjected to cyclic wet and dry conditions. 3D Boundary
Element Method is used to study theparameterslike,therate
of flow of current and the potential distributions. Corrosion
states were evaluated using results of Inverse Boundary
Element Method. The results were found to beinsignificantly
successful, when compared to the analytical results using
Boundary Element Method. The results of Inverse Boundary
Element Method analysis identify corroded areas more
prominently.
Yun Yong Kim et al. [19]haveusedHalf-CellPotentialTest
method in his experimental studies to evaluate the crack in
concretewhen exposedtochlorideattack.Thetestresultsare
obtained considering the effects of water-cementratio,crack
width and cover depth. Anti-corrosive techniques to

withstand chloride attack are proposed from the results. Jin
Xia et al. [15], study show the performance of RC columns
when it is embedded with corroded steel. 6mm and 20mm
hot-rolled reinforcing steel bars were used in the RC column
sections. The compressive strengths were determined using
cubes of size (150X150X150) mm with same mix
proportions. Corrosion was induced using the
electrochemical process. The columns were tested for
eccentric-compressive loading. Relationshipsconcerningthe
average c/sarea,strengthloss,andthemaximumcrackwidth
of concretecover wereestablished.Thequantitativeestimate
of the residual compressive strength of the corroded
reinforcedconcretecolumnwasobtainedusingload-carrying
capacity models. Lamya Amleh et al. [8] have conducted
investigationsontheexistingMontrealDicksonBridge.Spans
of 0.25m by 0.25 m on four randomly selected 5 m by 6 m
deck patchesare considered for analysis. A detailed research
was conducted to understand the reason behind the rapid
deterioration of the bridge. J. Helal et al. [18] discusses the
most common non-destructive test methods used in
structural engineering industry. The limitations, potential,
inspection techniques and interpretations are discussed.
Katalin Szilágyi et al. [36] have developed of a constitutive
model, i.e.SBZ-modelthatcanformulatethesurfacehardness
of the concrete. The relationship between the water–cement
ratio, the Rebound Number and the compressive strength of
concretehas beenestablishedconsidering28daysstrengthof
concrete. It also relates to the depth of carbonation and its
influence on the rebound index.
Shamsad Ahmad [37] discusses about various internal
and external factors causing corrosion in RC structures. The
rate of corrosion is measured using Linear Polarization
Method for in-situ concrete. Corrosion Mechanism and
parameters affecting corrosion in reinforced concrete
structures are also illustrated. With the use of different
models and experimental techniques, the enduring life of RC
structures can be predicted. Eugen BRÜHWILER et al. [38]
proposes three methods to reduce corrosion risk in concrete
i.e. by providing sufficient cover thickness to concrete
structures, or use of concrete with low permeability
properties, or by reducing the early age cracking of concrete.
Numerical models that allow the prediction of the initiation
phase of corrosion and early-age cracking of concrete
elements are also discussed in his study.Thefactorsaffecting
the hydration rateof concreteanditspermeabilityproperties
are also described in the paper. Tarek Uddin Mohammed et
al. [39] discusses about, the corrosion of steel in RC
structures when exposed to a marine environment.
Experiments include evaluation physical and chemical
properties of corrosion, presence of chloride ion, and
permeability properties of concrete. He concludes, the W/C
ratio has great influence on the magnitudes of corrosion. As
the narrow cracks heals considerably fast in the marine
environment, chances of reduction in corrosion rate can be
seen. Viktor Urban et al. [40] paper deal with experimental
tests on weathering steel bridges. The effects on the steelbar
when subjected to exposed the surface, and damage of
surfaces due liking water is discussed. It also explains the
relationship and dependence factors between measured
corrosion loss and the average thickness of corrosion
products. Razmjoo et al. [41] studied the relationship
between the location of thesteelbarandthecoarseaggregate
present in concrete. In the experimental process there
different samples were casted placing aggregates at three
different distances from the steel bar.
Results showed that, the location of the coarse aggregate
from the steel bar hassignificantinfluenceonthechlorideion
penetration and the initiation of corrosion in steel. It was
concluded that, by decreasing the distance between the
coarse aggregate and the steel bar can lower the initiation of
corrosion in reinforcedstructures.M.Goueygouetal.[42]has
conducted experiments on concrete cubes having surface
breaking cracks. The combination of non-destructive test
methodslikeResistivityMethodandUltrasonicPulseVelocity
method has been used. Three different mix concrete
specimens were used in his studies. Cracks were induced in
the section using Three Point Bending Setup apparatus. He
concludes as, both the testswascapableindetectingthemain
crack. However, a compound crack pattern and depth of the
crack was not considerably analyzed. Ngoc Tan Nguyen et al.
[43] studies involve the assessment of spatial variability, i.e.
the non-homogeneity of mechanical and physical properties
of concrete structures. It also briefs about the possible NDT
methods used for the assessment of these structural
components. The method of analysis adopted for the NDT
measurement is the variographicanalysis.Heconcludesthat,
combined NDT techniques developed has improved the
evaluation of concrete properties and also the assessment of
spatial variability in concrete structures.
3. CONDITION ASSESSMENT OF STRUCTURAL MEMBERS
3.1 VISUAL INSPECTION
Visual inspection is a very powerful tool, and it is one of
the most common and oldest non-destructive testing
methods that people have at home. A visual inspection can
give you a lot of information about the structure and its
condition, but it has some limitations and rules. The only
person who can doa visualinspectionissomeonewhoisvery
knowledgeable about structures, construction methods, and
materials. In this case, a visual inspection only gives an
impression of the visible problems,and the hidden problems
go unnoticed. It also doesn't give us any quantitative
information about how the material works. Because of these
limitations, visual inspection is not enough on its own. It
needs to be paired with other nondestructive and partly
destructive testing methods. With the help of BS1881: Part
201:1986.
The following are the physical observations made during
the inspection;
• Dampness was observed on walls below sill level at
many locations.

• Growth of Vegetation was observed at a few locations
nearer to the plinth.
• Dampness was observed on sunshades at many
locations.
• Plinth protection was observed to be damaged at some
locations.
• False ceiling was observed to be damaged at many
locations.
• Separation crack was observed between CRS and brick
masonry.
• Separation cracks were observed between masonry
joints at a few locations.
• Corrosion cracks were observed.
• Spalling and exposureof reinforcementwasobservedin
slabs at a few locations.
• Wooden purlins were observed to be decayed at some
locations.
• Cracks were observed in the existing WPC on the
terrace.
• Severe leakages & dampness was observed in theroof&
walls of the newly constructed toilet block.
• It was reported that, severe leakage was observed from
the expansion joint during monsoon season.
Fig -1: No Plinth Protection
Fig -2: Loosening of Motor
Fig -3: Distressed in wooden members
Fig -4: Dampness in columns

Fig -5: Cracks near Expansion Joint
Fig -6: Damaged false roofing and Truss
Fig -7: a) In-situ Non-destructive Tests
4. NON-DESTRUCTIVE TECHNIQUES
In the present scenario, it is observed that many important
reinforced and pre-stressed structures show distresswithin
a short period. These conditions are usually inspected and
restored only when the embedded steel is highly corroded,
followed by cracking and spalling of concrete. Quality of
structure can be maintained by Continues monitoring and
conducting periodic surveys. In order to protect rusting and
erosion of steel in reinforced concrete structures, few of the
major non-destructivetechniquesareproposedinthisstudy.
Fig -7: b) In-situ Non-destructive Tests
4.1 REBOUND HAMMER TEST
Rebound Hammer Test is a quick method to evaluate the
quality of concrete based on surface hardness of the existing
structure. The rebound number gives the average surface
compressive strength of the concrete. Rebound Hammer
Test was carried out on all accessible locations of R.C. slab
panels, beams, and columns in order to assess the surface
hardness / quality of in-situ concrete. Initially the surface
was prepared by removing the Plaster and dusting the
surface to get better results. Thetestwasconductedbyusing
‘Schmidt Rebound Hammer’ The results are presented in
Figure. And correspondingreferencestrengthispresentedin
Table 1.

Table -1: As per IS: 13311-(Part-II)-1992 (Reaffirmed in
2013) and Instrument manual furnished by M/s. Proceq,
Switzerland
Rebound
Number
Estimated Compressive
Strength Range (N/Sq.mm)
22 to 26 10 to 14
26 to 30 14 to 18
30 to 34 18 to 22
34 to 38 22 to 26
38 to 42 26 to 30
42 to 46 30 to 34
Fig -8: Shows Average Surface Compressive Strength of
RCC Columns. Beams and Slab
4.2 ULTRASONIC PULSE VELOCITY METHOD
Ultrasonic Pulse Velocity Test is being extensivelyusedto
assess the quality of concrete in general. This test is
generally used to check uniformity of concrete,
determination of cracks in the interior concrete,
honeycombing and assessment of concrete deterioration.
Ultrasonic Pulse Velocity Test was conducted on
accessible locations of R.C. Beams and Columns such as
Beam along outer slab panels, Beam along interior slab
panels, Column along outer slab panels, Column along
interior slab panels, Beam along edge discontinuous Slab
panel, Column along edge discontinuous Slab panel. The
transducers were coated with grease and placed on the
opposite side of beams and columns for better electrical
conductivity. Direct / Indirect method of scanning was
adopted at site. The tests were conducted using ‘PUNDIT
LAB+’ (Portable Ultrasonic Non-Destructive Digital
Indicating Tester) equipmentfromM/s.Proceq,Switzerland.
The results are presented in Figure 11. and the
corresponding reference quality grade chart is presented in
Table 2.
Table -2: Concrete quality grading for different velocity
criterion as reproduced from IS: 13311 (Part 1) – 1992
(Reaffirmed 2013)
Pulse Velocity
(km/sec)
Concrete Quality Grading
Below 3.0 Doubtful*
3.0 to 3.5 Medium
3.5 to 4.5 Good
Above 4.5 Excellent
Fig -9: Ultrasonic Pulse Velocity Measurements results on
selected members
4.3 HALF-CELL POTENTIAL TEST
In order to assess the extent of corrosion in reinforcing
bars of R.C members, ‘Half-cell Potential Difference
Measurement test’ was carried out on randomly selected
accessible locations of R.C members. The testwas conducted
using copper-copper sulphate half-cell solution. The test
results are presented in Figure 10.
Table -3: As per ASTM C876-91 Standards
Potential over
an area
Most likely outcome
more positive
than -200MV
90% probability that no reinforcing
steel is corroded at the time of test
-200 to -350
MV
corrosion activity of the reinforcing
steel
more negative
than -350 MV
90 % probability that reinforcingsteel
is corroded

Fig -10: Half-cell Potential Test Results of selected
Members
4.4 CARBONATION DEPTH MEASUREMENTS
To assess the extent of carbonation, i.e. the loss of
alkalinity (which is essential to protect the steel against
potential corrosion) in the cover concrete, colorimetric test
was carried out on randomly selected accessiblelocations of
R.C members using Phenolphthalein as indicator in dilute
methyl alcohol solution. This test was carried out by
removing the plaster and cover concrete to the required
depth. The exposed area was then drenchedwiththesample
solution prepared to check the amount of carbonation. The
test results are presented in Figure 11.
Fig -11: Carbonation depth measured at different
members
5. RESULTS AND DISCUSSION
• Based on the results obtained from Figure 8. for the
Rebound Hammer Test conducted on selected structural
members of the building, it is inferred that the strength of
the cover concrete of R.C Slab panels in Ground floor is only
satisfactory and also at few locations delamination of cover
concrete was observed. The results were concluded in
reference to Table 1.
• The results of Ultrasonic Pulse Velocity Test obtainedfrom
Figure 9. inferred that the quality of in-situ concrete in the
tested locations of the R.C. beams in Ground Floor wasfound
to be “Medium to Good” grade, as per Table 2.
• The Half-cell Potential Difference Measurement Test, was
carried out on the selected RC members and the results
obtained from Figure 10. inferred that, the corrosion of
reinforcing bars in the structure was observed to in the
“Initial Stage” (where no corrosion was observed) but in the
lintel beam it was observed to be in the “Moderate Stage”
(where corrosion was observed) with a need of proper
supervision. The results were concluded in reference to
Table 3.
• The Carbonation test results obtained from Figure 11.
showed that the cover concrete in the tested R.C. Slabs and
beams was carbonated up to reinforcement level and
initiation of corrosion can be observed.
6. REPAIR AND RESTORATION MEASURES
The building investigated in the study consists of many
distressed structural members leading to the corrosion of
reinforced steel. In order to increase the residual life of this
structure suitable repair and restoration measures have
been proposed based on the damage in the respective
structural members.
The building investigated in the study consists of many
distressed structural members leading to the corrosion of
reinforced steel. In order to increase the residual life of this
structure suitable repair and restoration measures have
been proposed based on the damage in the respective
structural members.
a) Replacing of existing AC sheets in the corridorregion:
In corridor areas the existing AC sheets at the firstfloorlevel
shall be replaced with metal sheets and the damaged
wooden joists shall be removed and replaced with new
wooden joists with existing dimensions.
b) Treatment for distressed madras roofing in the
corridor region:
In view of severe distress observed in the rear side corridor
region of Portion -7 consisting of madras roofing system
with wooden rafters, it is recommended to remove the
madras roofing system. It shall be replaced with R.C precast
slab panels with structural steel (ISMC) beams.
c) Treatment for Dampness and Spalling of cover
concrete in slab panels:
In view of the dampness and spalling of cover concrete in
slab panels, it is recommended to remove the existing
plastering & loosen the cover concrete up to the extent of
distress in a definite shape, i.e. square / rectangle. After a

thorough cleaning of the surface, if there is any presence of
corroded reinforcement, it is recommended to apply
anticorrosion chemical paints to the rebar and then the
portion shall be redone using polymer modified mortar.
d) Treatment for Damp patches & Peeling of plaster in
Walls:
The deteriorated plaster on masonry wallsatexteriorfaceof
the building shall be totally removed by gentle chipping. The
mortar joints in walls shall be deep racked and repointed
with CM 1:4 as per standard practice followed by re-
plastering with CM 1:6 mixed with water proofing agents.
e) Treatment for Expansion Joint:
In view of leakages from the expansion joint, it is
recommended to clean the joint and fill it with Polyurethane
sealant and redo the portion as perIS5256-1992 provisions.
f) Treatment for CRS masonry:
In view of dampness observed in CRS masonry, it is
recommended to remove the loosen mortar between the
masonry joints and redo it with cement mortar prior to
grouting.
g) Treatment for Terrace Slab:
To seal the cracks and also to improve the durability, it is
recommended to provide reinforcement concrete screed on
terrace integral with providing fillet at required corners of
the slab.
h) Strengthening beams and columns:
• RC beams can be strengthened by providing additional
cage of longitudinal and transverse reinforcement around
the beam and casting the concrete. The stirrups can be held
in position by drilling holes into the slab.
• The strengthening of RC beams can also be done by
inducing prestress to counteract the opposite moments
encountered during loading. To induce this prestress, wires
are introduced on both sides of the web and are anchored
against the end of the beam through a steel plate.
• Inadequate sections of RC column and beams can also be
strengthened by removing the cover concrete up to the
reinforcement level and welding new steel to present rebar
with the replacement of cover concrete. Initially the surface
shall be roughed and prepared for the effective replacement
of new steel with the introduction of grooves to facilitate
shear transfer.
7. CONCLUSION
The present paper focused on the condition assessment,
safety evaluation and possible repair and restoration
methods for existing aged RC building.
• Visual inspection showed that most of the region in the
building is subjected to distress due to spalling of concrete
cover; cracks near expansion joint, dampness and initiation
of corrosion in structural members have led todeterioration
of the structure.
• The proper maintenance and periodic surveys helps in the
restoration of aged RC buildings. The cracks in concrete
appeared on the concrete surface due the chemical reaction
can be eliminated by using proper grade of concrete, curing
and good compaction.
• Knowing the probability of corrosion, the buildings can be
restored by using different chemical treatments proposed
for steel. The embedded steel can also be protected using
cathodic protection of steel method, but the processmay not
be cost effective.
• Coating over steel bars is a short time solution for
buildings. This results in causing weak bonding between
steel and concrete. It is always recommended to use steel
before it reacts with the environment.
• The use of polymer modified mortar, paints with water
proofing compounds on the surfaces affected to dampness
and distress results in reuse of these buildingwith minimum
expenditures.
• It can be seen that detailed visual inspection and Non
Destructive Testing (NDT) play an important role in
condition assessment of existing buildings. It is emphasized
that using suitable NDT methods along with thorough
observations we can understand the level of distress and
with proper restoration measures under technical
supervision the residual life of the structure can be
enhanced.
REFERENCES
[1] [1] Chunhua Lu, Weiliang Jin, Ronggui Liu,
“Reinforcement Corrosion-Induced Cover Cracking Ans
Its Time Prediction for Reinforced Concrete Structures”
Corrosion Science, 53, (2011) 1337-1347.
[2] Amir Poursaee,“Corrosionmeasurementand evaluation
techniques of steel in concrete structures” Clemson
University, Clemson, SC, USA.edition, year of
publication..
[3] John P Brromfield, “Corrosion of Steel in Concrete-
Understanding- investigation and repair” 2nd edition,
year of publication, Taylor and Francis publications.
[4] M. Torres-Luque, E. Bastidas-Arteaga, F. Schoefs, M.
Sánchez-Silva, J.F. Osma, “Non-destructive methods for
measuring chloride ingress into concrete: State-of-the-
art and future challenges”, Construction and Building
Materials, Volume 68, 15 October 2014, Pages 68-81,
ISSN 0950-0618.

[5] Malcolm K. Lim, Honggang Cao, “Combining multiple
NDT methods to improve testing effectiveness”,
ConstructionandBuildingMaterials,Volume38, January
2013, Pages 1310-1315, ISSN 0950-0618.
BIOGRAPHIES
Kanchala Nanchari
(HOD, Department of Civil
Engineering,
ISL Engineering College,
Hyderabad, Telangana)
Shaik Mohd Ibrahim
(UG Student, Department of Civil
Engineering,
Khaja Omer Uddin
(UG Student, Department of Civil
Engineering,
Syed Azhar Uddin
(UG Student, Department of
Civil Engineering,
ISL Engineering
College, Hyderabad, Telangana)

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