Textile Reinforced Concrete 62332o

TEXTILE REINFORCED CONCRETE

NEED 

Concrete has low tensile strength, limited ductility and little resistance to cracking



Concrete develops micro-cracks, even before loading



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

TEXTILE REINFORCED CONCRETE is a composite material

consisting of mixtures of cement, mortar or concrete and discontinuous, discrete, uniformly dispersed suitable fibres or textile.The fibres used for making the fabric are of high tenacity like Jute, Glass Fibre, Kevlar, Polypropylene, Polyamides (Nylon) etc. The weaving of the fabric is done

either in a coil fashion or in a layer fashion. Molten materials, ceramic clays, plastics or cement concrete are deposited on the base fabric in such a way that the inner fabric is completely wrapped with the concrete or plastic.

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FACTORS AFFECTING THE PROPERTIES OF TRC 

Relative Fibre Matrix Stiffness



Volume of textile fibres



Aspect Ratio of the Fibre



Orientation of Fibres



Workability and Compaction of Concrete



Size of Coarse Aggregate



Mixing



Strength of the fibres

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1. RELATIVE FIBRE MATRIX STIFFNESS



Modulus of elasticity of matrix must be much lower 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 transfer

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2. VOLUME OF FIBRES



As seen in the graph, toughness and strength of the concrete increases with an increase in the volume of fibres 5

3. ASPECT RATIO OF THE FIBRE

Aspect Ratio of a fibre = Length/Diameter

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4. ORIENTATION OF FIBRES

The effect of randomness, was tested using mortar 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

The fibres are usually aligned in the direction of the tensile stresses in order to take up maximum stress.

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5. Workability and Compaction of Concrete Fibres reduce workability. The higher the volume of fibres, the tougher the compaction will be. Thus, the fibres must be used in reasonable proportions.

6. Size of Aggregate Size of coarse aggregates is restricted to 10mm

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7. MIXING Cement content

: 325 to 550 kg/m3

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/m3 : Glass -1% - 25 kg/m3 : Nylon -1% - 11 kg/m3

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TYPES OF TRC’S

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STEEL FIBRE REINFORCED CONCRETE (SFRC) 

Aspect ratios of 30 to 250



Diameters vary from 0.25 mm to 0.75 mm



Hooks are provided at the ends to improve bond with the matrix

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TYPES OF STEEL FIBRES

FIBRE REINFORCED CONCRETE

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FIBRE REINFORCED CONCRETE

FIBRE REINFORCED CONCRETE

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INTRODUCTION OF STEEL FIBRES MODIFIES: 1.

Tensile strength

2.

Compressive strength

3.

Flexural strength

4.

Shear strength

5.

Modulus of Elasticity

6.

Shrinkage

7.

Impact resistance

8.

Strain capacity/Toughness

9.

Durability

10.

Fatigue

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APPLICATIONS OF SFRC 

Highway and airport pavements



Refractory linings



Canal linings



Industrial floorings and bridge-decks



Precast applications - wall and roof s, pipes, boats, staircase steps & manhole covers



Structural applications

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POLYPROPYLENE FIBRE REINFORCED CONCRETE (PFRC) Advantages : 

Cheap, abundantly available



High chemical resistance



High melting point



Low modulus of elasticity

Applications : 

Cladding s



Shotcrete 16

GLASS FIBRE REINFORCED CONCRETE (GFRC) Advantages : 

High tensile strength, 1020 to 4080 N/mm2



Lengths of 25mm are used



Improvement in impact strengths, to the tune of 1500%



Increased flexural strength, ductility and resistance to thermal shock

Applications : 

Used in formwork, swimming pools, ducts and roofs, sewer lining etc.

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OTHER FIBRES

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ASBESTOS FIBRES



High thermal, mechanical and chemical resistance



Short in length (10 mm)



Flexural strength is 2 to 4 times that of unreinforced matrix



Contains 8-16% of asbestos fibres by volume



Associated with health hazards, banned in many countries

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CARBON FIBRES



Material of the future, expensive



High tensile strengths of 2110 to 2815 N/mm2



Strength and stiffness superior to that of steel

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ORGANIC/VEGETABLE FIBRES



Jute, coir and bamboo are examples



They may undergo organic decay



Low modulus of elasticity, high impact strength

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