Experimental Investigation on Behaviour of Reinforced

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World Academics Journal of ___________________________________________ Research Paper . Engineering Sciences

Vol.7, Issue.2, pp.88-91, June (2020) E-ISSN: 2348-635X

Experimental Investigation on Behaviour of Reinforced Concrete Beam

Using Jute Fibre Reinforced Polymer Laminates

Udhaya Sankari S.P.1*

, Umamaheswari R.2

1Dept. of Civil Engineering, Anna University Regional Campus, Madurai, Tamil Nadu, India

2Dept. of Civil Engineering, University College of Engineering, Dindigul, Tamil Nadu, India

*Corresponding Author: [email protected]

Available online at: www.isroset.org

Received: 15/Apr/2020, Accepted: 19/May/2020, Online: 30/June/2020

Abstract— This experiment comes under rehabilitation work. Now a day’s retrofitting is expanding worldwide and it is

one of the best option to make an inadequate building safe against future probable earthquake or other environmental force.

Replacing the damaged structure is one of the difficult process as well as cost intensive process and also risky work

therefore retrofitting is one of the best solution .The purpose of this experiment is to study the behaviour of reinforced

concrete beam before and after retrofitting by jute fibre wrap and the bond between jute fibre and concrete is done with the

help of general purpose resin (GPR) to increase the strength of deteriorated beam by using M35 grade concrete. The result

says about the increase in its strength.

Keywords—Jutefibrewrap, Retrofiting, GPR, Rehabilitation

.

I. INTRODUCTION

The maintenance, rehabilitation and repair of structural

members is one of the major problems in civil engineering

applications. The structure constructed in the past using the

older design codes in different part of the world are

structurally unsafe according to the new design codes. The

replacement of such a structure needs huge amount of

money as well as time. Structures are also gets deteriorated

due to chemical attack, deficiencies of material, inadequate

design, development of cracks. Retrofitting by using JFRP

bonded externally with the help of general purpose resin

have been studied in this experiment work. Recent research

is being focused on usage of FRP in order to strengthen the

existing RC framed structural elements without disturbing

the existing the structural elements

Retrofitting with the help of FRP to strengthen as well as

for repairing damaged structure is a new technique.

researches are going in this area using FRP in the RC

structure to study about the structural performance in terms

of strength and ductility

A) OBJECTIVE

The main objective is to assess the feasibility of

strengthening reinforced concrete and to study the

contribution of externally bonded jute fibre reinforced

polymer in confinement of reinforced concrete beam. This

experiment is focused on the strengthening of beam which

are not able to withstand the shear resistance. Beam has

been strengthen which posses weak in shear .the failure

behaviour of beam and its ultimate load carrying capacity

of beam were observed

Reasons leading to retrofitting

The building which are designed under gravity load. Lack

of study on seismic zone. Improper planning and lack of

timely revisions of codes of practice and standards

Reasons for wrapping

It is light in weight, low cost, corrosion proof, easy to

install. The ratio of strength to weight FRP is more than

fifty times that of steel. It increases ductility and strength

of concrete beam. In the wrapping process it requires less

installation of time and also it does not change its original

features of structure

B) MATERIALS USED

Cement: Ordinary Portland Cement and Portland

Pozzolana Cement are the two most common types of

cement used in construction industries. It resist to dry

shrinkage and cracking. In this experiment we have used

OPC 53 grade cement .

Table 1.1: Cement properties

Properties Result

Initial setting time 30 minutes

Final setting time 10 hours

Fineness modulus 5%

Consistency 33%

Specific gravity 3.15

Fine aggregate: Fine aggregate consist of natural sand,

crushed stone sand and crushed gravel stone dust. It should

be passing through the IS 4.75mm size. For this study

river sand is used.

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World Academics Journal of Engineering Sciences Vol.7, Issue.2, June 2020


Table 1.2: Sand properties

Properties Result

Grading of sand Zone II

Fineness modulus 5.34%


Water absorption 0.8%

Coarse aggregate: Locally available crushed granite

coarse aggregates are used in this project, having the

maximum size of 10mm and it should be of hard, free from

dust, dirt and other foreign matters.

Table 1.3: Coarse aggregate properties

Properties Result


Impact value 30.08%

Crushing value 40.71%

Water absorption 4.38%

Jute fibre: Jute is a natural fibre and it is easily available

at cheapest rate. It has high tensile strength and low

extensibility

Table 1.4: jute fibre properties

Properties Result

Tensile strength (MPa) 250

Elastic modulus(GPa) 1.6

Elongation at fracture(%) 22.7

Thickness(mm) 1.5

Stiffness(KN/mm) 2

GSM(gram per square meter) 260

Fig: 1.1 jute fibre sheet

General purpose resin (GPR): It is suitable for both hand

layup and gun spray up. It has good mechanical property,

impact and water resistance

Table 1.5: GPR properties

Properties Value

Density (g/cm3) 1.1


Water: In this experimental work, potable water is used

for casting and curing of specimens. The pH value for the

water used should not be greater than 6.

II. LITERATURE REVIEW

Robert Ravi and Prince Arulraj (2010) they have done on

the experimental investigation on the control and

retrofitted beam column joints using CFRP and GFRP

hybrid wrapping and this paper concluded about the energy

absorption capacity of the beam column joints was found

to be 24.2% and it increases when compare with the

conventional specimen.

Balasubramanian et al (2007) in this paper they have

evaluated about the performance carbon and glass fibre

reinforced polymer wrapping used for retrofitting of the

beams and columns and ii concluded that the performance

was improved after retrofitting with the help of FRP

wrapping and it compare the both carbon and glass, they

provide almost similar performance. The RC columns

retrofitted with the single layer it posses good ductility

index , maximum strains.

Franceso Bencardino et al (2002) In this experiment they

have investigated about the strengthening of reinforced

concrete beam in flexure and shear with the help of

externally bonded bidirectional carbon fibre fabric to

overcome the bond slip and plate separation at the end.

This paper concluded that it provides an effective alternate

to laminates strengthening the existing structure

N.F. Grace et al(1999) this paper says about the using of

various types of FRP laminates in the structure. The carbon

and glass FRP have been used , it is externally bonded with

the beams with the help of epoxy resin and also this paper

says about the different layers of FRP sheet , types of

epoxy as well as its strengthening pattern. In this paper

they have concluded by calculating its absorbed energy to

total energy and behaviour of strengthening of beams are

exhibits in higher factor of safety in design

III. EXPERIMENTAL PROGRAMME

The beams were casted by M30 grade concrete and Fe 450

steel with the guidelines of code book IS 10262:2019. The

beams were wrapped with the JFRP where its thickness is

1.5mm and bonded externally with the help of general

purpose resin. In this study the retrofitted beam is

compared with the conventional beam. Before wrapping

the beam the initial load is given, that is the load is given

till the initial crack is appear then it is released from the

load and general purpose resin is applied on the beam and

JFRP is wrapped and then it is allowed for sun dried for 7

days after that the wrapped beam is tested.

A) CASTING OF BEAM

The beams are casted as per the design consideration

which includes conventional as well as beam need for

retrofitting. All the beams are casted according to the mix

design after that quantity of the material is calculated as

per the dimension of the beam, the volume of the beam is

0.024m3. After weighting the materials as per the quantity

all the coarse aggregate, fine aggregate, cement has to



mixed by adding required water after providing steel

reinforcement.

After placing the reinforcement cage into the beam mould

the concrete mix has to be poured into the mould in the

forms of layers. After filling first two layers it has to be

vibrate so that the air voids can be avoided and after filling

the next layer also we have to vibrate. At last level the top

surface by using trowel. The beams are removed from the

mould after 24 hrs and curing is done for 28 days

Fig: 3.1(a) casting

B) PROCESS OF WRAPPING JFRP

The first step is to clean the surface of the specimen

completely with the help of brush and JFRP is cut as per

the dimension of the specimen for each beam the sheet

dimension is 400X1600 mm and the pattern used for

wrapping is U pattern. In the wrapping pattern there are

various types of patterns are there such as U shape, V

shape, and I shape among them U pattern is recommended

since it helps to resist the load when compare with the

other type pattern. Finally the general purpose resin is

applied thoroughly in the bean immediately the JFRP is

wrapped and then allowed to sun dry.

Fig: 3.2(b) wrapping and dry

C) TESTING PROCEDURE The retrofitted beams and the conventional beams were

tested under two point bending load in order to know the

ultimate bearing capacity. The two supports were

considered as simply supported condition then I sectional

girder beam was placed to apply the two point loading on

the beam the loading was applied to the centre of the

specimen and transmitted to two points loading until

failure and note down the corresponding deflection from

the dial gauge.

Fig: 3.3(c) 1. Conventional beam

Fig: 3.3(c) 2. Retrofitting first the bean is allowed to obtain initial

crack

Fig: 3.3(c) 3. Wrapped beam is tested



IV. RESULTS AND DISCUSSION

Two sets of beams were tested under the loading condition

and the beams are in simply supported condition and

finally the comparison of conventional and retrofitted

specimens were analyzed from the result.

A) FOR CONVENTIAL BEAM The test result for the convention beam are

Table 4.1: Test result

Compressive strength 36.4 KN/m2

Split tensile strength 2.41 KN/m2

Flextural strength 5.25 KN/m2

0

1

2

3

4

5

6

7

8

9

10

5 10 15 20 25 30 35 40 42

load (KN)

de

fle

ctio

n (

cm)

A

B) FOR WRAPPING SPECIMEN

i) In this first the beam is given load till it obtain the initial

crack and its graph between deflection vs load are

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

2 4 6 8 10 12 14

load (KN)

de

fle

ctio

n (

cm)

A

ii) After the beam is given initial load , the beam is

wrapped with JFRP bonded with GPR (general purpose

resin). Then the beam is kept for sundry after its

completely dry the specimen is tested and its graph

between deflection vs load are

0

1

2

3

4

5

6

7

8

9

10

4 8 12 16 20 24 28 32 36 40 44 48

load (KN)d

efl

ect

ion

(cm

)

A

V. CONCLUSION

From the result we can conclude that

I) comparing both the conventional and wrapped specimen

we can say that the strength of the wrapped beam is

increased by 47.6% when comparing with the conventional

beam.

II) It is more economical when compare to other FRP.

III) The serviceability of the structure gets increased.

REFERENCES

[1]. Uji k. “Increasing the shear capacity of existing reinforced

concrete structure members by applying with the help of carbon

fibre sheetsˮ. Transaction of the japan concrete institution,volume

14. 1992

[2]. Miyachui K. “increasing the strength of concrete column with the

help of carbon fibre sheetˮ. Transactions of the japan concrete

institute, volume 21, 1999.

[3]. Raju A. and Matew L.A. “ Retrofitting of RC Beam using FRPˮ.

International journal of engineering research and technology

(IJRET), 2(1),2013,PP.6-10.

[4]. Hamid R. and Allan H. “concrete beams externally bonded with

FRP platesˮ. journal of composite for construction , ASCE, 1(5),

2001,PP.45-56.

[5]. Rohit V and Manideep K. “ Retrofitting of RC beams using glass

fibre reinforced polymer sheetsˮ. Indian journal of science and

technology (IJST), 9(44),2016, pp.1-11.

Documents

Experimental Investigation on Behaviour of Reinforced