What is Fiber Reinforced Concrete

Srinivasan

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Sep 7, 2017
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What is Fiber Reinforced Concrete
PCC has low tensile strength, limited ductility and little resistance to cracking. PCC develops micro-cracks, even before loading Addition of small, closely spaced and uniformly distributed fibres act as crack arresters.

Fiber Reinforced Concrete is a composite material consisting of mixtures of cement, mortar or concrete and discontinuous, discrete, uniformly dispersed suitable fibers

Factors Affecting The Properties Of Fiber Reinforced Concrete
Relative Fiber Matrix Stiffness,Volume of Fibers,Aspect Ratio of the Fiber
Orientation of Fibers, Workability and Compaction of Concrete
Size of Coarse Aggregate,Mixing
Modulus of elasticity of matrix must be much lower than that of fiber. E.g. steel, glass, carbon
Fibers with low modulus of elasticity- nylon, polypropylene
Inter-facial bond between the matrix and the fibers determine the effectiveness of stress transfer
The effect of randomness, was tested using mortar specimens reinforced with 0.5% volume of fibers, by orienting them:
parallel to the direction of the load, perpendicular to the direction of the load, in random
Workability and Compaction of Concrete - Fibres reduce workability

Size of Aggregate = Size of CA is restricted to 10mm
Cement content = 325 to 550 kg/cum
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%
Fiber content = 0.5 to 2.5% by vol of mix
Steel -1% - 78 kg/cum
Glass -1% - 25 kg/cum
Nylon -1% - 11 kg/cum

Types Of Fiber Reinforced Concretes
  • Steel Fiber Reinforced Concrete (SFRC ),
  • Polypropylene Fiber Reinforced Concrete (PFRC)
  • Glass Fiber Reinforced Concrete (GFRC)
  • Steel Fiber 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

Introduction of steel fibers modifies :
  • Tensile strength
  • Compressive strength
  • Flexural strength
  • Shear strength
  • Modulus of Elasticity
  • Shrinkage
  • Impact resistance
  • Strain capacity/Toughness
  • Durability
  • Fatigue
Applications of Steel Fiber Reinforced Concrete
  • Highway and airport pavements
  • Refractory linings
  • Canal linings
  • Industrial flooring's and bridge-decks
  • Precast applications - wall and roof panels, pipes, boats, staircase steps & manhole covers
  • Structural applications