flexural behaviour of fibre reinforced ferrocement concrete

FLEXURAL BEHAVIOUR OF STEEL FIBRE

REINFORCED AND LATEX MODIFIED

FERROCEMENT SLABS

BY

ABRAHAM JAMES FINNEY

DIVYA RUBAN

SANTHOSH KUMAR

GOVINDARAJ

Project guide

Mr.S.Sivachandran

Asst professor

Civil department

FERROCEMENT

Mixture of portland cement and sand applied over

layers of woven or expanded steel mesh

Desired shape can be built.

Economical.

Lesser cross sectional area.

Relatively thin, compound curved sheets to make

hulls for boats, shell roofs, water tanks, etc

LATEX

• Latex -carboxylate styrene butadiene copolymer.

• Improves bond strength.

• Increases flexural & compression strength

• Enhances impact strength.

• Resistance to hydrolysis.

MICRO STEEL FIBER

• Increases structural integrity.

• It contains short discrete fibers that are uniformly

distributed and randomly oriented.

• Controls cracking.

• They also reduce the permeability of slab.

• It produce greater impact, abrasion, and shatter–

resistance in concrete.

Ferrocement structure

Micro Steel FibreThe Process of cutting the Welded mesh

Construction of a Ferrocement tank

OBJECTIVES

To identify various ingredients used for Ferrocement slabs.

Preliminary study on properties of materials used in this project.

Mix design of cement : sand ratio is 1:2.

Comparison of mechanical properties of steel fibre reinforced

cement mortar Ferrocement slabs and latex modified reinforced

cement mortar Ferrocement slabs.

Comparison of Strength between two types of Ferrocement

slabs by adding different layers of welded mesh.

Analysis of test results and arrive conclusions.

METHODOLOGY

Literature review on Ferrocement slabs.

Study of codal provisions.

Collection of welded mesh, steel fibres, latex and other ingredients.

Preliminary tests on materials.

Design of mortar mix.

Casting of the Ferrocement slabs.

Flexural strength and the mechanical properties such as ductility,

toughness and energy of all specimens to be calculated.

Analysis of the test results.

Comparison of the results obtained.

Conclusion.

APPLICATIONS OF FERROCEMENT ELEMENTS

Strengthening of RC Beams using Ferrocement

Laminates

Water Tanks

Secondary Roofing Slabs

Sunscreens

Hulls of boats

sculptures

MATERIALS SPECIFICATION

Cement: Portland Pozzolanic Cement of grade53

Fine aggregate: Ordinary river sand sieve of size

2.36 .

Mortar: Cube specimens of size 70 mm x 70 mm x

70 mm

Micro Steel fibres : length 13mm,dia 0.15mm

Steel Mesh: Diameter 1mm, grid size 1 X 1 cm.

DESIGN OF FERROCEMENT SLABS

No. of

speci

mens

Name of The

Specimen

No of layers of welded

meshes

Size of the slab

(mm)

Cement: Sand

Mix ratio

1 A1 4 600 × 300 1:2

1 A2 6 600 × 300 1:2

1 A3 8 600 × 300 1:2

Batch A-Steel fibre reinforced cement mortar Ferrocement slab

Weight of the cement = 20 kg

Weight of sand = 40 kg

Weight of water = 4.7 litre

Weight of steel fibres = 2 kg

Weight of the 4 layered mesh, A1 = 444gm

Weight of the 6layered mesh, A2 = 712gm

Weight of the 8 layered mesh, A3 = 1.045 kg

The total weight of the 4 layered slab = 9.55 kg

The total weight of the 6 layered slab = 11.36 kg

The total weight of the 8 layered slab = 11.85 kg

Batch A- Steel fibre reinforced cement mortar Ferrocement slab

BATCH B: LATEX MODIFIED STEEL FIBRE

REINFORCED FERROCEMENT SLAB

No. of

specimens

Name of The

Specimen

No of layers of welded

meshes

Size of the slab

(mm)

Cement:Sand

Mix ratio

1 B1 4 600 × 300 1:2

1 B2 6 600 × 300 1:2

1 B3 8 600 × 300 1:2

Batch B

Weight of the cement = 20 kg

Weight of sand = 40 kg

Weight of water = 2.82litre

Weight of steel fibres = 2 kg

Weight of the latex = 950ml

Weight of the 4 layered mesh, B1 = 444gm

Weight of the 6layered mesh, B2 = 712 gm

Weight of the 8 layered mesh, B3 = 1.045 kg

The total weight of the 4 layered slab = 12.01 kg

The total weight of the 6 layered slab = 12.25 kg

The total weight of the 8 layered slab = 12.40 kg

TESTS ON MORTAR CUBE

The mix proportion of the mortar cube

Cement : sand : water ratio : 1 : 2 : 0.47

S.no Days Compressive Strength (MPa)

1 0 0

2 3 21.50

3 7 23.01

4 28 33.22

Compressive Strength of mortar specimens

COMPRESSIVE STRENGTH DEVELOPMENT CURVE FOR

MORTAR CUBE

TESTING OF FERROCEMENT SLABS

Casting of the slabs specimen

Curing

Preparation for test specimens

Flexural test on Ferrocement slabs

Specimen placed in closed mould

Casting of the slabs specimen

Deflectometer placed on the Ferrocement

slab specimen

The specimens are subjected to flexural

strength test using UTM machine

DEFORMATION AND CRACKING BEHAVIOR OF

SLABS UNDER FLEXURAL LOADING.

Slab

I.D

First

Cracking

load

(KN)

1ST

cracking

central

deflection

(mm)

No of

cracks at

first crack

Spacing

at first

crack

(mm)

Ultimate

load

(KN)

Ultimate

load

Deflection

(mm)

No of

cracks at

ultimate

load

Crack

spacing at

ultimate

load

(mm)

A1 4 3.53 5 220 5.6 13.44 54 10

A2 4 2.33 6 40 7.28 8.44 32 20

A3 4.4 2.34 2 40 10.08 16.49 26 10

B1 3.2 4.21 7 30 5.6 13.01 23 15

B2 2 1.99 6 30 5.68 8.5 17 25

B3 3 2.15 5 30 8.4 16.64 30 15

0

1

2

3

4

5

6

0 5 10 15

Lo

ad

(K

N)

Deflection (mm)0

1

2

3

4

5

6

7

8

0 2 4 6 8 10

Lo

ad

(K

N)

Deflection (mm)

0

2

4

6

8

10

12

0 2 4 6 8 10 12 14 16 18

Lo

ad

(K

N)

Deflection (mm)

Batch A

A1 A2

A3

0

1

2

3

4

5

6

0 5 10 15

Lo

ad

(K

N)

Deflection (mm)

0

1

2

3

4

5

6

0 5 10 15 20

LO

AD

(Kn

)

DEFLECTION(mm)

0

1

2

3

4

5

6

7

8

9

0 5 10 15 20

LO

AD

(K

N)

DEFLECTION(mm)

Batch B

B1

B3

B2

FLEXURAL STRENGTH

FORMULA USED

R = P*L / b*𝑑2

NO OF LAYERS FLEXURAL STRENGTH

(Kn/m2)

BATCH A BATCH B

4 1.4388 1.5476

6 1.7384 2.1384

8 2.4355 4.1362

ENERGY ABSORPTION CAPACITY

No of layers Batch A

(KN mm)

Batch B

(KN mm)

4 2.62 2.823

6 4.977 5.83

8 5.22 6.15

ENERGY = AREA UNDER THE LOAD DEFLECTION CURVE

COMPARISON OF ENERGY ABSORPTION

CAPACITY

0

1

2

3

4

5

6

7

8

1 2 3 4

No of layers

Ferro- steel fibre (J/sec)

Ferro-latex and steel fibre (J/Sec)

CALCULATION OF DUCTILITY VALUE

No of layers Batch A Batch B

4 1.4 1.875

6 1.82 2.84

8 2.7 3.36

Ductility = Ultimate load / First cracking load

Formula used

COMPARISON OF DUCTILITY VALUE

0

200

400

600

800

1000

1200

1400

1 2 3 4

No of layers

Ferro- steel fibre

Ferro-latex and steel fibre

CALCULATION OF TOUGHNESS VALUE:

No of layers Batch A Batch B

4 382.86 589.83

6 628.31 1026.02

8 1180.33 1337.55

Toughness = Total area of the curve/ area up to first crack obtained curve.

COMPARISON OF TOUGHNESS VALUE:

0

200

400

600

800

1000

1200

1400

1 2 3 4

No of layers

Ferro- steel fibre (mm)

Ferro-latex and steel fibre (mm)

RESULTS

Specimen Flexural

strength

Energy

absorption

value

Ductility Toughness

B1>A1 7.69 % 7.75 % 33.9% 54.05%

B2>A2 23.82 % 17.14% 56.04% 63.21%

B3>A3 69.95 % 17.82% 24% 13.32%

The below table shows the increase in percentage of the Flexural strength

and mechanical properties of Latex modified Steel fibre reinforced

ferrocement slabs over Steel fibre reinforced ferrocement slabs

CONCLUSION

Thus from the above comparison it is evident that the

latex modified steel fibre reinforced cement mortar

Ferro cement slabs of 4, 6 and 8 layers are having a

greater flexural strength and mechanical properties.

Thank You