INTERNATIONAL JOURNAL OF CIVIL ENGINEERING … ACTION OF... · This paper presents the flexure studies on ferro cement ... slab which was opposite to the face ... International Journal

International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print),

ISSN 0976 – 6316(Online) Volume 4, Issue 3, May - June (2013), © IAEME

57

COMPOSITE ACTION OF FERROCEMENT SLABS UNDER STATIC

AND CYCLIC LOADING

Dr. T.Ch.Madhavi*,

Shanmukha Kavya .V**

, Siddhartha Das**

,

Sri Prashanth .V**

, Vetrivel .V**

*Prof & HOD, Civil Engg, SRM University, Ramapuram Chennai-600 089, India.

**BE (Final Year), SRM University, Ramapuram, Chennai-600 089, India.

ABSTRACT

Ferrocement is a composite material that can be used for construction of certain

structures such as ships, water tanks, boats and other similar structures, where we need not

use lot of resources such as coarse aggregates. This paper presents the flexure studies on ferro

cement slabs, where the number of reinforcing weld mesh layers are varied as 2 layers, 3

layers and 4 layers. 6 slabs are cast, 2 each for each type of reinforcing, i.e., 2 slabs of 2

layers, 2 slabs of 3 layers, 2 slabs of 4 layers, using custom made moulds. They are tested for

static and cyclic loading conditions of flexure testing after 28 days of curing. After the tests,

the results are tabulated and represented graphically and analysed. It is found that, increasing

the number of layers of mesh increases the flexural strength of the ferro cement slabs. Also,

as the number of layers increase, the crack propagation is slow.

Key Words: Ferro Cement Slabs, flexure, Static loading, cyclic loading

INTRODUCTION

Ferro cement is a composite material made up of cement mortar and reinforcement in

the form of layer of mesh. Ferro cement consists of closely spaced, multiple layers of mesh or

fine rods completely embedded in cement mortar. A composite material is formed that

behaves differently from conventional reinforced concrete in strength, deformation, and

potential applications, and thus is classified as a separate and distinct material. It can be

formed into thin panels or sections with only a thin mortar cover over the outermost layers of

reinforcement. Compared to other cement concrete structures, those made of ferrocement are

light weight, tough, durable, crack resistance and can be made into virtually any shape1. Over

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ISSN 0976 – 6308 (Print)

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58

the years, applications involving ferrocement have increased due to its properties such as

strength, toughness, water tightness, lightness, ductility and environmental stability.

Ferrocement may be cast in various shapes and forms even without the use of form work and

are aesthetically very appealing. Ferrocement has a very high tensile strength to weight ratio

and superior cracking behaviour in comparison to reinforced concrete2. Hence, Ferrocement

is an attractive material for construction of shell, folded plate, ribbed slab and housing

components. The slenderness of these elements may adversely affect their performance under

working loads. Hence, there is a need to study their (a) first crack strength and (b) load-

deflection (P-d) behaviour. While (a) and (b) characterize the serviceability behaviour of

ferrocement elements, it is equally important to predict their flexural strength.

Wail N. Al-Rifaie3 et al studied the structural behaviour using two ferrocement

channel-like beams to form I-cross-section beam and indicated that ferrocement can be used

in construction of buildings. Y. Yardim et al4 (2008), investigated the performance of

inverted two-way ribs precast ferrocement thin panel as permanent formwork and found that

the thin panel with suitable ribs layout and support distance can be used as permanent

formwork. Jalal .A. Saeed et al4 tested ferrocement one way slabs with openings subjected to

two point loads taking into consideration number of mesh layers and size of the openings as

variables. The results showed that by increasing number of mesh layers the slabs flexural

strength increased and size of the openings have negative effect on flexural strength of the

slabs. Essam Eltehawy observed the influence of using Ferrocement in enhancement of the

mechanical properties of reinforced concrete slabs subjected to impact, penetration and fire.

Deeptha Shri. S (2012) studied the flexural behaviour of self-compacting concrete (SCC)

ferrocement fiber reinforced slab panels.

EXPERIMENTAL INVESTIGATION

6 ferrocement slabs of dimensions 600 mm x 300 mm and 25 mm thickness and

welded mesh in 2, 3 and 4 layers are tested under static and cyclic loading. Ordinary

Portland cement, River sand and potable water are used. Welded wire mesh of 3mm diameter

and 25 mm x 25 mm spacing is used. Chicken mesh is used on either sides of the layer

formed. Normal binding wire is used to tie up the welded wire mesh with each other and

chicken mesh to form the core of the slabs. 1:3 cement mortar with a water cement ratio of

0.48 was prepared.

Fig1 Reinforcement of slab Fig.2 Reinforcement placed in the mould



59

Fig 3. Test Setup Fig 4. Failure of slab

The slab is placed under 2 point load with dial gauge fixed to it as shown in fig 3 and

tested till failure as shown in fig 4.

RESULTS AND DISCUSSIONS

The deflections were measured at the mid-span and the first crack and ultimate loads are

noted.

Static loading

First Crack Loading In static loading, the slab with 3 layer shows 68.75% increase in first crack load from

the slab with 2 layers. Similarly the slab with 4 layers has increased by 87.5% . Hence the 3

layer slab shows considerable increase over the 2 layers slab as shown in table 1 below.

Table1: First Crack and Ultimate loads under static loading

Sl.

No.

Specimen First Crack

Load

(kN)

% increase

in first

crack load

Ultimate

Load

% increase

in Ultimate

load

1 2 Layer 3.2KN - 5.6kN -

2 3 Layer 5.4KN 68.75 % 8.4kN 50 %

3 4 Layer 6KN 87.5 % 9.7kN 73.21 %

Ultimate Load The ultimate failure is a bit low for the 2 layer mesh slab, 5.6 kN. But the ultimate

failure is relatively high for both 3 layer and 4 layer mesh slabs i.e, 8.4 kN and 9.7 kN

respectively. This shows an increase of 50% over 2 layer slab. The 4 layer slab shows an

increase of 15.47% ultimate strength than 3 layer slab and 73.21 % over the 2 layer slab.



60

Fig 5. Load Deflection Curves Fig 6. Load Deflection Curves

(Static load) (Cyclic load on 2 layer slab)

Load deflection Curves The load deflection curves were plotted for FC/2L, FC/3L and FC/4L as shown in fig.

5. The curves are almost linear for all the 3 slabs in static loading. But towards failure, there

is a sudden increase in deflection. Hence the deflection increases gradually for lesser loads.

And as the loads increase, deflection increases.

Cyclic Loading

First Crack load

In cyclic loading, the slab with 3 layer shows 46.15% increase in first crack load from

the slab with 2 layers. Similarly the slab with 4 layers has increased by 89.47%. Hence the 4

layer slab shows considerable increase over the 2 layers slab.

Ultimate load The ultimate failure is a bit low for the 2 layer mesh slab, 3.9 kN. But the ultimate

failure is relatively high for both 3 layer and 4 layer mesh slabs i.e, 4.3 kN and 8.2 kN

respectively. This shows an increase of 10.25% over 2 layer slab. The 4 layer slab shows an

increase of 15.47% ultimate strength than 3 layer slab and 110.25 % over the 2 layer slab

Table2: First Crack and Ultimate loads under cyclic loading

Sl.

No.

Specimen First Crack

Load

(kN)

% increase

in first crack

load

Ultimate

Load

(kN)

% increase in

Ultimate load

1 2 Layer 1.3 - 3.9 -

2 3 Layer 1.9 46.15 % 4.3 10.25 %

3 4 Layer 3.6 89.47% 8.2 110.25 %

02

02

42

0

24

64

2

0

2

4

6

86

4

2

0

2

4

6

8

8.2

0

5

10

15

20

25

0 5 10

De

fle

ctio

n i

n m

m

Load in kN



61

Fig 7. Load Deflection Curves Fig 8. Load Deflection Curves

(Cyclic load on 3 layer slab) (Cyclic load on 3 layer slab)

CRACK PATTERNS

The cracks under flexure loading were observed to be parallel to each other, and they

were in the plane perpendicular to load application. The cracks appeared on the face of the

slab which was opposite to the face of load application. It is also observed that in the 4 layer

mesh slab, the first crack appeared very later, and the increase in the cracks, upon application

of load was slow.

CONCLUSIONS

1. Increasing the number of layers of mesh increases the flexural strength of the

ferrocement slabs.

2. Slabs with highest number of layers of wire mesh have highest flexural strength under

both types of loading.

3. The flexure strength under static loading increased by 50% % for 3 layer slab, from 2

layer slab. It further increases by 15.47 % for 4 layer slab over 3 layer slab.

4. The percentage increase of flexural strength of static loading condition of 4 layer slab

over 2 layer slab is 73.21%

5. The flexure strength under cyclic loading increased by 10.25 % for 3 layer slab, from 2

layer slab. It further increases by 90 % for 4 layer slab.

6. The percentage increase of flexural strength of cyclic loading condition of 4 layer slab

over 2 layer slab is 110.25%

7. As the number of layers increase the crack propagation is slow, and the crack spacing is

least for 4 layer mesh slabs, which ultimately leads to better load bearing capacities.

8. It was also seen that, as the number of layers increases, it is difficult to pack them into

layer into same thickness

0

2

0

2

4

2

0

2

4

6

4

2

0

2

4

6

7

00

5

10

15

20

25

30

35

0 2 4 6 8

De

fle

ctio

n i

n m

m

Load in kN

0

2

0

2

4

2

0

2

4

5

4

2

0

2

4

00

2

4

6

8

10

12

14

16

18

20

0 2 4 6

de

fle

cto

n i

n m

m

load in kN



62

REFERENCES

1. Anitha .M et. al. Coimbatore, India (2012). “An experimental investigation on the

flexural behaviour of SCC ferrocement slabs incorporating fibres”, International Journal

of Engineering Science and Technology,Vol. 4; No. 5; pp 2146-2158.

2. Ezzat. H. Fahmyet. al. Cairo, Egypt (2009).“Ferrocement sandwich and cored panels for

floor and wall construction”, “our world in Concrete and structures”.

3. Dr.Wail N. Al-Rifaie andMuyasser M. Joma’ah, Tikrit, Iraq (2010). “Structural

behaviour of ferrocement system for roofing”, “Diyala Journal of engineering sciences” ,

pp-237-248

4. Y.Yardim et. Al (2010), “Performance of Precast Ferrocement Panel for Composite

Masonry Slab System”, “International Conference on Construction and Building

Technology”, 2008, ICCBT 2008 - B - (36) – pp397-408.

5. Jalal .A. Saeed, PaymanH. Mohammad , and lbrahimH. Aziz, (2008). “Behaviour and

flexural strength of ferrocement one way slabs with square openings”, “Journal of

Zankoy Sulaimoni”, Vol. 1 No.1.

6. K. Sasiekalaa and R. Malathy, “Flexural Performance of Ferrocement Laminates

Containing Silicafume and Fly Ash Reinforced with Chicken Mesh”, International

Journal of Civil Engineering & Technology (IJCIET), Volume 3, Issue 2, 2012,

pp. 130 - 143, ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316.

7. Mohammed Mansour Kadhum, “Effect of Dynamic Load: Impact of Missile on

Mechanical Behavior of Ferrocement – Infrastructure Application”, International Journal

of Civil Engineering & Technology (IJCIET), Volume 4, Issue 2, 2013, pp. 295 - 305,

ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316.

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INTERNATIONAL JOURNAL OF CIVIL ENGINEERING … ACTION OF... · This paper presents the flexure studies on ferro cement ... slab which was opposite to the face ... International Journal