Concrete Essay

Introduction

Concrete is widely used in constructions and that is because it can be easily placed and handled and could be casted into various shapes and forms, like any other construction material concrete has its advantages and disadvantages, many studies have been done to reduce the disadvantages and minimize their effects on structures, some of the disadvantages are listed below.

1. Low tensile strength.

2. Low post cracking capacity.

3. Brittleness and low ductility.

The presence of micro cracks in the concrete play a significant role in decreasing the strength of plain concrete, this problem can be solved by adding different fibers in the mixture of the concrete, many kinds of concrete can be used one of them is steel fibers which we

Although these methods increase the tensile strength of concrete members, the inherent tensile strength of concrete is not increased. When the concrete is loaded the micro cracks called ‘first crack’ develops. This leads to inelastic deformation of concrete. It has been found that addition of small closely spaced and uniformly dispersed fibers having very small diameter and length would act as crack arrestor and improves the dynamic and static properties. This type of concrete is called fiber reinforced concrete. It defined as a composite material consisting of concrete and discontinuous, discrete, uniformly dispersed fibers. In which, Steel Fiber is one of the most commonly used fibers. Generally round fibers, of diameter varying from 0.25 to 0.75mm are used. Steel fibers make significant improvements in flexural impact and fatigue strength of concrete. The weak matrix in concrete, when reinforced with steel fibers, uniformly distributed across its entire mass, gets strengthened enormously, thereby rendering the matrix to behave as a composite material with properties significantly different from conventional concrete. Because of the vast improvements achieved by the addition of fibers to concrete, there are several applications where Fibers Reinforced Concrete (FRC) can be intelligently and beneficially used. These fibers have already been used in many large projects involving the construction of industrial floors, pavements, highway-overlays, etc.”