ABSTRACT

Concrete is considered as the major construction material due to its versatility and performance. However, efforts are made to overcome the inherent deficiencies and weaknesses of the concrete, such as its low tensile strength, britility etc. Different techniques and materials are used to improve the ductility of the concrete because micro cracking occurs in the concrete due to shrinkage and creep which ultimately converts in the wide cracks lending to failure under the load particularly tension and bending. One of the options is to add fibers in concrete to minimize the micro cracking because the fibers in concrete are believed to act as crack arresters. This study focused on to use the polypropylene fiber in the concrete which are readily available in the market. Fibers of uniform size 19mm were used with the dosage from 0.05 % to 0.5% of the weight of the cement with an increment of 0.05%. The concrete of I :2:4 mix proportions with 0.5% w/c ratio was cast. In all 11 batch (33 prism specimens) were cast including one batch of normal concrete without PP fibers. The effectiveness of PP fibers was studied in terms of the workability, flexural strength and deflection. Slump tests were carried to determine the workability and the prism specimens were tested with two point loading under bending to determine the flexural strength and the deflection at the mid span of the specimens. The results remarkable enhancement of the flexural strength of the order of 53% with 0.4% of PP fiber. The deflection also improved, while the slump value (Workability) decreased due to addition of fibers. Based on the results of the study conducted, the polypropylene fibers are suggested to use as fiber reinforcement in terms of flexural strength but with appropriate dosage while proper workability of the concrete be maintained.