fiber reinforced concrete(1)

8/13/2019 Fiber Reinforced Concrete(1)

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F I B R E R E I N F O RC E D

C O N C R E T E

Presented by

Bellum Ramamohana Reddy

097Q1A0107


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CONTENTS:

NeedsFactors Affecting The Properties Of FrcTypes of Frcs Steel fibre Reinforced Concrete (SFRC)

Types of steel fibersIntroduction of steel fibres modifiesApplications of SFRCPolypropylene Fibre Reinforced Concrete (PFRC)Glass Fibre Reinforced Concrete (GFRC)Carbon fibresConclusion 2

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NEED

PCC has low tensile strength, limited ductility andlittle resistance to cracking

PCC develops micro-cracks, even before loading

Addition of small, closely spaced and uniformlydistributed fibres act as crack arresters.

FIBRE REINFORCED CONCRETE is acomposite material consisting of mixtures ofcement, mortar or concrete and discontinuous,discrete, uniformly dispersed suitable fibres. 3

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FACTORS A FFECTING T HE PROPERTIES O F FRC

Relative Fibre Matrix Stiffness

Volume of Fibres

Orientation of FibresWorkability and Compaction of Concrete

Size of Coarse Aggregate

Mixing

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1. R ELATIVE F IBRE MATRIX S TIFFNESS

Modulus of elasticity of matrix must be muchlower than that of fibre. E.g. steel, glass,

carbon

Fibres with low modulus of elasticity- nylon,

polypropylene

Interfacial bond between the matrix and the

fibres determine the effectiveness of stress

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3. O RIENTATION OF F IBRES

The effect of randomness, was tested usingmortar specimens reinforced with 0.5% volume

of fibres, by orienting them:

parallel to the direction of the load

perpendicular to the direction of the load

in random

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4. Workability and Compaction of

ConcreteFibres reduce workability

5. Size of AggregateSize of CA is restricted to 10mm

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6. M IXING Cement content : 325 to 550 kg/m 3

W/C Ratio : 0.4 to 0.6

% of sand to total aggregate : 50 to 100%

Maximum Aggregate Size : 10 mm

Air-content : 6 to 9%

Fibre content : 0.5 to 2.5% by vol of mix

: Steel -1% - 78kg/m 3

: Glass -1% - 25 kg/m 3

: Nylon -1% - 11 kg/m 39

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T YPES O F F RC S

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STEEL F IBRE REINFORCED CONCRETE (SFRC)

o Diameters vary from 0.25 mm to 0.75 mm

o Hooks are provided at the ends to improve

bond with the matrix

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I NTRODUCTION OF STEEL FIBRES MODIFIES :1. Tensile strength2. Compressive strength3. Flexural strength

4. Shear strength5. Modulus of Elasticity6. Shrinkage7. Impact resistance8. Strain capacity/Toughness9. Durability10. Fatigue

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APPLICATIONS OF SFRC

Highway and airport pavements

Canal linings

Industrial floorings and bridge-decksPrecast applications - wall and roof panels, pipes,

boats, staircase steps & manhole covers

Structural applications

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POLYPROPYLENE F IBRE REINFORCED CONCRETE (PFRC)

Cheap, abundantly available

High chemical resistance

High melting pointLow modulus of elasticity

Applications in cladding panels and shotcrete

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GLASS F IBRE REINFORCED CONCRETE (GFRC)

High tensile strength, 1020 to 4080 N/mm 2

Lengths of 25mm are used

Improvement in impact strengths, to the tuneof 1500%

Increased flexural strength, ductility and

resistance to thermal shocko Used in formwork, swimming pools, ducts and

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CARBON F IBRES

Material of the future, expensiveHigh tensile strengths of 2110 to 2815 N/mm 2

Strength and stiffness superior to that of steel

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CONCLUSION

Fiber reinforced concrete structures are having hightensile strength.Less cracks

Load bearing capacity

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fiber reinforced concrete(1)

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