STUDY OF FLEXTURAL BEHAVIOR OF POLYPROPYLENE SYNTHETIC FIBER REINFORCED CONCRETE BEAM

Abstract

Polypropylene synthetic fiber reinforced concrete has higher flexural strength than ordinary concrete. Because fibers in matrix hold the concrete together while flexural stress makes a crack happened until the fiber was pulled out or was broken off, it helps fiber reinforced concrete improved ductility. This article shows a result of the study about flexural behavior of polypropylene synthetic fiber reinforced concrete beam, that made from fiber with 45-58mm. length, embossed surface and has tensile strength about 520 and 600MPa. It was added to slab and pavement concrete construction with 280 and 320ksc of compressive strength at 28 days of cube specimen like concrete in general construction and design works. By using amount of fiber in 0, 2 and 3 kg. for one cubic meter of concrete and test concrete notch beam according to EN14651 with 3 points flexural strength testing. The result found that polypropylene synthetic reinforced concrete can resist higher load of testing after crack was occurred by 100% of load and was increased for 2kg of fiber adding, 131% of load was increased for 3kg of fiber adding. In the other hand, ordinary concrete beam cannot increase a load of testing and cannot resist loading after crack was occurred. This study shows polypropylene synthetic fiber adding in concrete offer higher ductility of concrete and higher portion of polypropylene synthetic fiber in concrete can increase ductility of concrete too. But quality control of fiber reinforced concrete construction is highly important because if the fibers are not distributed across the section, the strength of the concrete will not be as expected.