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EXPERIMENTAL INVESTIGATION ON REHABILITATION OF CORRODED CONCRETE BEAM SPECIMENS

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International Journal of Civil Engineering and Technology (IJCIET)
Volume 10, Issue 3, March 2019, pp. 581-587. Article ID: IJCIET_10_03_059
Available online at http://www.iaeme.com/ijciet/issues.asp?JType=IJCIET&VType=10&IType=3
ISSN Print: 0976-6308 and ISSN Online: 0976-6316
© IAEME Publication
Scopus Indexed
EXPERIMENTAL INVESTIGATION ON
REHABILITATION OF CORRODED
CONCRETE BEAM SPECIMENS
Sathish Kumar. K, S. Vinothkumar
Assistant Professor, Department of Civil Engineering
Bharath Institute of Higher Education and Research (BIHER),
Bharath University, Chennai.
Dr. R. Venkatakrishnaiah, Dr. S. J. Mohan
Professor, Department of Civil Engineering.
Bharath Institute of Higher Education and Research (BIHER),
Bharath University, Chennai.
*Corresponding Author
ABSTRACT
Corrosion of steel support is one of the primary solidness issues confronting
fortified solid frameworks around the world. This proposition a bridge the
consequences of trials to explore the feasibility of utilizing remotely fortified glass
fiber strengthened polymer (GFRP) laminates to rehabilitate corrosion-damaged
reinforced concrete beams. Twelve beams were casted with an admixture of rice husk
ash and coating of Nitro-Zinc primer over the surface of the rebars. The beams were
strengthened externally by applying I so- Resin bonding GFRP laminates to the
concrete surface the results showed that the use of GFRP sheets for strengthening
corroded reinforced concrete beam specimens is an efficient technique that can
maintain structural integrity and enhance the behavior of such beams
Keywords: Rehabilitation of Corroded Concrete.
Cite this Article: Sathish Kumar. K, S. Vinothkumar, Dr. R. Venkatakrishnaiah and
Dr. S. J. Mohan, Experimental Investigation on Rehabilitation of Corroded Concrete
Beam Specimens, International Journal of Civil Engineering and Technology, 10(3),
2019, pp. 581-587.
http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=10&IType=3
1. INTRODUCTION
Corrosion of reinforcing steel is a major problem facing the concrete infrastructures all over
the world. Many structures in unfavorable conditions have encountered unsatisfactory
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Experimental Investigation on Rehabilitation of Corroded Concrete Beam Specimens
misfortune in serviceability or security far sooner than expected because of the consumption
of fortifying steel and in this way require substitution, restoration or reinforcing. Corrosion
presents a problem for reinforced concrete (RC) structures for two reasons. This work deals
with the GFRP composite as an additional material with steel reinforcement. Mats and fabrics
are used for strengthening purpose of RC members. They are applied externally in RC
structures and the behavior is studied subsequently. The external application of the fibers
with polymer resin for effective bonding for the fiber mats immensely increases the strength
of RC beams.{1} Concrete is then poured into the forms encasing the strands. As the concrete
sets, it bonds to the tensioned steel. When the concrete reaches a specific strength, the strands
are released from the abutments. This compresses the concrete, arches the member, and
creates a built-in resistance to service loads.
Table 1 Guideline for Identification of Corrosion Prone Location Based on Chemical Analysis
Sl. No
1
2
3
4
Test results
High pH values greater than 12.0 and very low
chloride content
High pH values and high chloride content
greater than threshold values (0.4 to 0.6 % by
weight of cement)
Low pH values and high chloride content
(greater than 0.4 to 0.6 % by weight cement)
Low pH values and high chloride content
Interpretations
No corrosion
Corrosion prone
Corrosion prone
Corrosion prone
2. SELECTION OF THE MIX PROPORTION
The blend embraced for all pillars were 1:1.831:2.59 by load of concrete: fine total: coarse
total and water bond proportion of 0.34. The genuine material required for every example
was gauged and precisely blended and table vibrated for compaction.
3. DESCRIPTION OF TEST SPECIMEN
Twelve numbers of concrete beams of 1000 mm length and 100mm x 150 mm in section
were cast.
3.1. Companion Specimen
Absolutely twelve bars were thrown and tried. Alongside each bar three blocks of 150 x 150
x 150 mm estimate, were thrown on a similar date, with a similar solid blend, which were
utilized for the relating examples. The sidekick examples were tried and compressive quality
were resolved. The partner examples were compacted and relieved like the pillars. The
examples were tried by the IS Code516-1964.
3.2. Cube Crushing Test
The 3D shape smashing test was done in pressure testing machine. The heap was connected
according to IS Code 516-1964. The rate of stacking was around 14 N/mm2 every moment
and a definitive burden were noted.TEST RESULTS:
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Sathish Kumar. K, S. Vinothkumar, Dr. R. Venkatakrishnaiah and Dr. S. J. Mohan
3.3. Comparison of Compressive Strength of Cube Specimens
COMPRESSIVE STRENGTH IN
MPA
(OPC, OPC+RHA, OPC+SF- 28 Days)
50
40
OPC
30
OPC+RH
20
OPC+SF
10
0
1
2
3
OPC
39.55
40
40.44
OPC+RH
28.44
28.89
29.33
OPC+SF
39.11
39.55
40
NO OF SPECIMENS
3.4. Preparation of the Beam Specimens
3.4.1. Mould
The bar form is made of teak wood. Inside estimations of the shape are 100 mm wide 150
mm significant and 1000 mm long. The form was cleaned and shape oil was associated with
keep up a vital separation from hold of bond with the shape and for straightforward departure.
The steel form is used for all 3D shapes. These molds were cleaned and openings were
stacked with mortar of Paris putty and oiled before tossing.
3.4.2. Casting
The real amount of materials were gauged and kept prepared before blending. The molds
were kept prepared on table vibrator with support set in position with spread squares. The
solid was blended by solid blender and filled in the form by three layers and compacted well
by table vibrator each time for span of 10 seconds. Following 24 hours the pillar and buddy
examples were expelled from the molds and set outside and relieved by putting the example
in fiber restoring tank for 28 days.
4. TESTING METHODOLOGY
4.1. Details of the Test Specimen
For the examination of chloride incited fortification consumption in solid structures under
administration loads, 12 shaft examples were thrown utilizing M 50 evaluation of cement.
Every one of these examples were kept in salt free water for a time of 28 days for restoring.
There are numerous components, which impact the consumption of support. A portion of
these components are perceptible and some are most certainly not. The examples of the test
customized were structured so that the impact of recognizable factor is estimated. The extent
of the present work manages the finding of the impact of following factors on consumption of
rebar's in cement
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Experimental Investigation on Rehabilitation of Corroded Concrete Beam Specimens
Table 2 Variables Considered
Cement
Coating
Conditions
Loading
Mix
Size of beam
Ordinary Portland Cement (OPC) and Ordinary Portland cement replaced
partially by Rice Husk Ash cement (RHAC) (10% by weight of cement)and
Ordinary Portland cement replaced partially by Silica fume(10% by weight
of cement)
Uncoated, Nitro Zinc Primer
Stressed
5% above crack load
5% below crack load
M 50
1000 mm x 100 mm x 150 mm
4.2. Mix Design Proportions
For M 50 Mix -- 1:1.831:2.59 with a W/C ratio of 0.34
4.3. Beam Specifications and Loading Details
Beams are cast with fresh concrete (as per design mix – M50) using admixture.
5. TEST PROCEDURE
To explore the beginning of chloride incited help utilization of strong structures in watery
chloride course of action and the synchronous organization stacks, the precedents were cut
back to back with the ultimate objective of mirroring the stacked condition of the bar. The
test setup for the columns under concentrated on condition. he stacking centers are set at 300
mm center to center, by using point and shock affiliation and the bars were kept in right
position one over the other. Edges of size 75 mm x 75 mm x 8 mm, electrical releases 25 mm
and length 450 mm and nuts of separation crosswise over 26.5 mm were used. The focuses,
stray pieces were secured with Zinc-Copper Alloy to keep up a vital separation from the
Galvan static Corrosion (commonly this happens when two unique materials are accessible).
5.1. Tests on Specimen
5.1.1. Load Test on R.C. Beams
After the fruition of quickened erosion process, the RC pillars were exposed to two-point
burden to start unadulterated twisting in center 33% range. The bar was upheld on a pivot at
left hand side and roller at right hand side. To quantify the redirection, the dial check was
settled at mid-range of the pillar. Slow static burdens were connected and relating
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Sathish Kumar. K, S. Vinothkumar, Dr. R. Venkatakrishnaiah and Dr. S. J. Mohan
redirections were watched. Burden at inception of splits, break proliferation and split width
were noted. The bars were tried upto the inception of breaks as appeared in Figure.
FAILURE PATTERN OF BEAM SPECIMEN BEFORE REHABILITATION
5.2. Preparation of Beams for Fixing GFRP
The beams were taken out after 15 days of accelerated corrosion process and the dirt on the
surface were wiped off and allowed to dry inside the room for two days. On the third day the
surface was cleaned thoroughly. Strengthening of beams were carried out using glass fibre
reinforced polymer (GFRP) composites as shown in Fig. Finally, all the beam specimens
were prepared with GFRP composite as shown in Figure.
BEAM SPECIMENS LAMINATED WITH GFRP
6. OBSERVATIONS OF LOAD TEST
After the accelerated corrosion process for a period of 15 days, the beam specimens were
subjected to load test upto crack load. Then the specimens were strengthened using GFRP
composites. The specimens were subjected to load test once again.
6.1. Pattern of Cracks
During the load test before rehabilitation, initial cracks appeared in the load range of 26 to 40
kN for all the beams and vertical cracks developed during the later stages of testing. After the
load test, the beams are wrapped with GFRP composites on bottom and two side surfaces.
After rehabilitation the beam specimens were once again subjected to load test upto failure.
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Experimental Investigation on Rehabilitation of Corroded Concrete Beam Specimens
FAILURE PATTERN OF BEAM SPECIMEN AFTER REHABILITATION
Table 3 Weight Loss Of Rebars Before And After Corrosion
Beam
Designation
UCOPCH2
UCOPCH14
NZOPCH22
NZOPCH23
UCRHH4
UCRHH12
NZRHH24
NZRHH27
UCSF5
UCSF8
NZSF19
NZSF21
Weight in gms.
Initial
Final
2609
2532.2
2633
2568.8
2625
2570.6
2571
2527
2632
2574.6
2572
2522.8
2607
2565.2
2597
2560.9
2588
2520.35
2602
2544.5
2581
2532.9
2603
2562.95
% Weight loss
2.94
2.43
2.07
1.71
2.18
1.91
1.60
1.39
2.61
2.21
1.86
1.54
Table 4 Comparison of Load Before And After Rehabilitation
Beam
Designation
UCOPCH2
UCOPCH14
NZOPCH22
NZOPCH23
UCRHH4
UCRHH12
NZRHH24
NZRHH27
UCSF5
UCSF8
NZSF19
NZSF21
Load (kN)
Before Rehabilitation After Rehabilitation
26.28
66.81
33.95
72.44
36.04
77.95
34.88
78.77
36.04
62.76
34.24
59.56
40.68
73.26
36.04
69.14
34.99
67.6
31.16
63.18
38.36
75.61
35.46
73.96
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586
Increase
in %
60.66
53.13
53.76
55.72
42.57
42.51
44.47
47.87
48.23
50.68
49.26
52.05
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Sathish Kumar. K, S. Vinothkumar, Dr. R. Venkatakrishnaiah and Dr. S. J. Mohan
7. CONCLUSION
1. The Failure Load for the Specimens Cast with Ordinary Portland concrete was more
than the examples of OPC with 10% substitution of rice husk cinder bond, OPC with
10% substitution of silica smoke.
2. while contrasting the weight reduction of rebars, the examples cast with OPC
indicates more weight reduction than that of the examples Cast with OPC with 10%
substitution of rice husk fiery remains concrete, the examples Cast with OPC with
10% substitution of Silica Fume.
Based on experimental results it has been concluded that all the strengthened beams were
able to carry more load than the corresponding virgin beams. This indicates that the
strengthening technique adopted is effective. Wrapping with GFRP laminates in flexural zone
along with the bottom surface increases the load carrying capacity
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Issue 2 ISSN: 0974-2115
Pradeep H.R and ShashiShankar A. (2005),“Analysis and Assessment of Strength
Development in Controlled Low strength Materials”, ICI materials journal Vol.84, PP.
27-35.
Dr Surendra P.Bhatnagar (2007),“Building Rehabilitation, Deterioration, Corrosion And
Sustainable Safe Living Needs Priority”, Civil Engineering Construction Journal Vol 58,
PP.74-76.
Atul K.Desai (2008),“Method Of Health Monitoring Of Structures”, Civil Engineering
Construction Journal Vol 65, PP.39-49.
Dr. A.K.Mullick (2005), “High Performance Concrete in India-Development, Practices
and Standardizations”, ICI Journal Vol.53, PP.7-14.
Dr.Rakesh Kumar (2005),“Self-Health Monitoring Concrete”, ICI Journal Vol 34 PP.1518
T.S.Nagaraj (2006), “Phenomenological Model for Assessment of Strength Development
in Class F-Fly Ash –Based Geopolymer Mortars” ICI Journal Vol 46 PP. 23-27
IS:456-2000, Plain and Reinforced Concrete - Code of Practice
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