Experimental Investigation on Steel Fibers in the Concrete

Cement concrete is the most extensively used construction material in the world. The reason for its extensive use is that it provides good workability and can be moulded to any shape. Ordinary cement concrete possesses a very low tensile strength, limited ductility and little resistance to cracking. Internal micro cracks, leading to brittle failure of concrete. In this modern age, civil engineering constructions have their own structural and durability requirements, every structure has its own intended purpose and hence to meet this purpose, modification in traditional cement concrete has become mandatory. It has been found that different type of fibers added in specific percentage to concrete improves the mechanical properties, durability and serviceability of the structure. It is now established that one of the important properties of Steel Fiber Reinforced Concrete (SFRC) is its superior resistance to cracking and crack propagation. In this work effect of fibers on the strength of concrete for M 20 grade have been studied by varying the percentage of fibers in concrete. Fiber content were varied by 0.50%, 1%, and 2% by volume of cement. Cubes of size 150mm x 150mm x 150mm to check the compressive strength and beams of size 750mm x 100mm x 100mm for checking flexural strength were casted. All the specimens were cured for the period of 7, 14 and 28 days before crushing. The results of fiber reinforced concrete for 7days, 14days and 28days curing with varied percentage of fiber were studied and it has been found that there is significant strength improvement in steel fiber reinforced concrete. The optimum fiber content while studying the compressive strength of cube is found to be 1% and also 1% for flexural strength of the beam. Also, it has been observed that with the increase in fiber content up to the optimum value increases the strength of concrete. Slump cone test was adopted to measure the workability of concrete. The Slump cone test results revealed that workability gets reduced with the increase in fiber content.