Question

What are the types of fibres reinforced concrete and how do fibres effect the properties of concrete.

Answer 1

Fiber reinforced concrete contains fibres material which increases its structural integrity.

The types of fiber reinforced concrete are as follows :

1.Steel Fiber Reinforced Concrete:

a) Fiber made from mild steel drawn wire.

b)The typical diameter lies in the range of 0.25 to 0.75mm.

2.polypropylene Fiber Reinforced (PFR) cement mortar & concrete:

a) Polypropylene fibers being hydrophobic can be easily mixed as they do not need lengthy contact during mixing and only need to be evenly distressed in the mix.

3) GFRC – Glass Fiber Reinforced Concrete:

a)Glass fiber is made up from 200-400 individual filaments which are lightly bonded to make up a stand.

b) The major appliance of glass fiber has been in reinforcing the cement or mortar matrices used in the production of thin-sheet products.

4)Asbestos Fibers:

a) The naturally available inexpensive mineral fiber, asbestos, has been successfully combined with Portland cement paste to form a widely used product called asbestos cement,which is four times that of unreinforced matrix.

5)Carbon Fibers :

Carbon fiber comes under the very high modulus of elasticity and flexural strength. These are very expensive.

6)Organic Fibers:

Organic Fibers are chemically more inert than either steel or glass fibers.

A large volume of vegetable fiber may be used to obtain a multiple cracking composite.

Effect of fibers on properties of the concrete:

1.They lower the permeability of concrete and thus reduce bleeding of water.

2.High modulus fibers such as steel, glass and carbon impart strength and stiffness to the composite.

3.Use of higher percentage of fiber is likely to cause segregation and harshness of concrete and mortar.

4.Incorporation of steel fiber decreases the workability considerably.

5.The inter-particle friction between fibers and between fibers and aggregates controls the orientation and distribution of the fibers and consequently the properties of the composite.