Presentation on Flexure Behaviour of Ferrocement Strengthened RC beams made by Axay Dhariwal under guidance of Prof Sunil Raiyani, Nirma Institute of Technology at #33NCCE #IEIGSC

1. Title of Paper-
Flexure Behaviour of Ferrocement Strengthened
RC beams
33RD NATIONAL CONVENTION OF CIVIL ENGINEERS,
AHMEDABAD
Author(s) Name-
1. Akshay Dhariwal (14BCL008), Civil Engineering department, Institute of Technology,
Nirma University, Ahmedabad, Gujarat
2. Prof. Sunil Raiyani, Civil Enginnering department, Institute of Technology, Nirma
University, Ahmedabad, Gujarat
Technical Session II

2. CONTENT
 Introduction
 Objectives
 Literature Review
 Experimental Programme
 Results and Discussion
 Conclusion
 References

3. INTRODUCTION
 ACI defines Ferrocement as "a type of thin wall reinforced concrete
commonly constructed of hydraulic cement mortar, reinforced with
closely spaced layers of continuous and relatively small diameter
mesh"[1]
 Used for construction of light-weight, hard and strong surfaces in
any shapes
 Used for retrofitting of structural members
 Steel wire mesh induces higher tensile strength, crack resistance and
high ductility

4. OBJECTIVES
 To understand the behaviour of RC beams under transverse load
 To find out the load carring capacity and cracking pattern of
ferrocement beams
 To compare the experimental results of normal beams and ferrocement
beams
 To compare the experimental results with non linear finite element
solution for the beams

5. LITERATURE REVIEW
The strengthening of reinforced concrete beam using Ferro-cement
onto surface of beams has been done by Paramsivam et al. [2]
Bong and Ahmed [3] have investigated about short term behaviour of
Ferro-cement beam and its advantages
Ebead et al. [4] examined the inexpensive strengthening techniques
for partially loaded reinforced beams where it is not possible to
remove entire live load effect

6. EXPERIMENTAL PROGRAMME
 6 Beams are casted as doubly reinforced beam with dimensions
150×150×1300 mm
Reinforcement detailing is given in Fig. 1, Fig. 2 and Fig. 3
Figure 1 Longitudinal section and loading details

7. (a) BN2-16
(b) BN2-12-10 (c) BN2-10-12
Figure 2 Cross section for Normal beams- (a) (b) and (c)

8. (a) BF2-16
(b) BF2-10-12
(c) BF2-12-10
Figure 3 Cross section for Ferrocement beams- (a) (b) and (c)

9.  Concrete Mix design as per IS: 10262 – 2009[5]
Grade of concrete M25
Maximum nominal size of aggregate 20mm
Slump 75mm
Fine aggregate zone II
Exposure condition Moderate
Specific gravity of cement of OPC 53 grade 3.15
Specific gravity of coarse aggregate 2.69
Specific gravity of fine aggregate 2.7
Table 1 General design data
Material proportion
Cement 1
Fine aggregate 1.716
Coarse aggregate 3.11
Water 0.5
Table 2 Mix proportions

10. Table 3 Cube Results
Table 4 Properties of wire mesh
Mesh
size(mm)
Wire
diameter(mm)
Yield
stress(MPa)
Ultimate stress
(MPa)
22.5 0.62 650 715
Cubes Compressive Strength at 28 days(MPa)
1 30.25
2 33.36
3 31.25
Average strength 31.62

11. Motar Mix-
 The recommended range of mortar mix proportion for Ferro-
cement is 1:1.5 to 1:2.5 (cement: sand) by weight and water-
cement ratio is about 0.5[6]
 In our case the mix proportion is taken as 1:2 (cement: sand)
and water is taken as 0.4
Figure 4 Casting of Ferrocement beams

12. The casting of beams is done in two stages
1. Normal beams
2. Ferro-cement beams
Instrumentation and Testing setup
Figure 6 Testing SetupFigure 5 Casting of Normal beams

13. RESULTS AND DISSCUSION
Behaviour of normal beams and ferrocement beams, under transverse
loading, were compared with the help of results like central deflection,
first crack load and ultimate load
At a regular interval of the load, central deflection of all beams are
measured up to failure
For understanding the role of ferrocement in flexural strengthening,
failure mechanism and failure pattern of all beams were observed
Experimental results are compared with analytical solution carried out
with help of ABAQUS Finite element software
Stress strain relation for concrete and steel derived by Belarbi and
Hsu[7,8] taken as an input material property to model the RCC beam

14.  Comparison of load – central deflection behavior -
(a) Load – Deflection
behavior: Type of
tension reinforcement 2
– # 16 mm
(b) Load – Deflection
behavior: Type of tension
reinforcement 2 – #12 mm &
2 – #10mm (bottom)
(c) Load – Deflection
behavior: Type of tension
reinforcement 2 – #10 mm
& 2 – #12mm (bottom)
Figure 7 Load v/s Central deflection diagram

16. Cracking pattern of Ferrocement beam-
Figure 9 BF2-16 after failureFigure 8 BF2-12-10 after failure

17. Figure 10 Failure pattern for Normal beam and Ferrocement beam

18.  The result of normal beams and ferrocement beams for ultimate load
and cracking load and corresponding deflection are summarized in the
Table 5
Beam First crack
load(kN)
Deflection at
Cracking load
(mm)
Ultimate
load(kN)
Deflection at
ultimate
load(mm)
Failure
BN2-16 20 3.10 25.00 4.19 shear
BN2-12-10 20.65 3.40 32.29 6.80 Flexure
BN2-10-12 20.45 3.08 32.81 6.91 Flexure
BF2-16 24.79 3.80 27.55 4.40 1st Crack was
observed in
Ferrocement mould
BF2-12-10 25.00 3.54 33.06 6.36
BF2-10-12 24.50 3.33 35.81 7.10
Table 5 Crack and ultimate load and corresponding deflection

19. Ductility factor had been found in order to validate the strengthening
effect of ferrocement mould
The flexural ductility factor defined by
Here,
= ultimate curvature and
= yield curvature
 This factor indirectly represent the amount of energy a member can
store during plastic deformations and as such represents the ductility or
energy absorbing capacity of the member [9]
 If yield curvature is not distinct properly then by regression analysis
derived formula can use to evaluate the ductility factor [9]
u
y

 

u
y
(1)

20. 0.45 1.25 1.1 3
10.7( ) [( ) / ] [1 95.2( ) ( ) ]   
     

c
ck t c bo ck
t
f f
(2)
 In present case for all the beams the compression steel ratio is smaller than
one quarter of the tension steel ratio. So, last is very close to 1.0
(3)
 In conventional design the tension steel ratio in reinforced concrete beam
section to not more than 75% of the balanced steel ratio
0.45 1.25
10.7( ) [( ) / ]ck t c bof  
    
Total length of Chicken wire mesh (mm) Total no of wires Total area
(mm2)
= 130 (bottom width) + 2×70 (height up to
Neutral axis for tension region on both side) =
270
=12 Nos.
= 12×0.302
= 3.624
270
22.5(size)
Table 6 Area of chicken wire mesh in tension

21. Properties of all tested specimen like dimensions, area of steel and ductility factor
are summarized in Table 7 and The ductility factor for the each beam calculated as
defined in above eqution
Beam Cross
Section
(mm2) (MPa)
Area of tensile
reinforcement
(mm2)
Area of
compression
reinforcement
(mm2)
Area of
Chicken
wire mesh
Ductility
factor
(calculated
as per Eq. 3)
BN2-16
31.62
402.12
100.53
- 4.64
BN2-12-10 383.27 - 4.74
BN2-10-12 383.27 - 4.74
BF2-16 402.12 3.624 5.34
BF2-12-10 383.27 3.624 5.47
BF2-10-12 383.27 3.624 5.47
ckf
150 150
Table 7 Ductility factor for all tested beams

22. CONCLUSION
1. The load – deflection curve of the tested beams shows increase in ultimate
as well as cracking load and deflection
2. The first crack load in the case of ferrocement beam is nearly 25 % higher
compare with normal beam. Initial cracks are observed in Ferrocement
mould and propagate into RCC part of the beam
3. The difference between cracking load and ultimate load is merely 10%. It
may be due to debonding of ferrocement mould was observe after first
crack. It is recommended to provide the tie connector or shear connector
between RCC beam and Ferrocement mould
4. Ductility of all the strengthened beams are higher compare with normal
beams
5. The behavior of ferrocement strengthened RC beam in flexural is predicted
by FE analysis using ABAQUS Software and compared the results with
experimental results. Its shows in good agreement

23. REFERENCES
1. ACI Committee 549 report (1993), “Guide for Design, Construction and
Repair of ferrocement”, ACI 549.1 R-93
2. Paramasivam, P., Lim, C.T.E. and Ong, K. C. G., (1998), “Strengthening
of RC Beams with ferrocement Laminates”, Cement and Concrete
Composites, 20:1, 53 – 65
3. Bong, J.H.L and Ahmed, (2010), “Study the Structural Behaviour of
ferrocement Beam”, UNIMAS e-Journal of Civil Engineering, 1:2
4. Ebead, U. (2015), “Inexpensive Strengthening Technique for Partially
Loaded Reinforced Concrete Beams”, Journal of Materials in Civil
Engineering, 27:10
5. IS 10262:2009, “Indian standard for Concrete mix proportioning”
Bureau of Indian standard

24. 6. Makki, R. F. (2014), “Response of Reinforced Concrete Beams
Retrofitted by ferrocement”, International Journal of Scientific and
Technology research, 3:9, 27 – 34
7. Belarbi, A. and Hsu, T.T.C., (1994) “Constitutive laws of concrete in
tension and reinforcing bars stiffened by concrete”, ACI Structural
Journal, 91:4, 465 – 474.6
8. Belarbi, A. and Hsu, T.T.C., (1995) “Constitutive laws of softened
concrete in biaxial tension – compression”, ACI Structural Journal,
92:5, 562 – 573
9. Kwan, A.K.H, Ho, J.C.M and Pam, H.J. (2002), “Flexural strength and
ductility of reinforced concrete beams”, Proceedings of the Institution
of Civil Engineers Structures & Building, 152:4, 361 - 369

25. THANK YOU