Experimental study on mechanical properties and durability properties of hybrid fibre reinforced concrete using steel and banana fibres

摘要

The Fibre Reinforced Concrete (FRC) possesses a high flexural strength, improved ductility and high energy absorption capacity than that of conventional concrete against dynamic loads. When the concrete is reinforced with randomly dispersed fibres it prevents micro cracks form widening1. The combination of various types of fibres results in the formation of hybrid fibre composites. One type of fibre improves the properties of fresh concrete and prevents early shrinkage cracks while the other type of fibre contributes to the improvement of strength and durability of hardened concrete. The scope of the present study is to investigate the influence of different combination of hybrid fibres (steel and banana fibres) on the behavior of Reinforced Concrete (RC) structural elements with hybrid fibres. The laboratory experiments have been conducted with normal plain concrete and fibrous concrete. The mechanical properties such as compressive strength, tensile strength and modulus of elasticity and durability properties such as resistance to chemical attack were investigated in the laboratory test. The RC beams have been designed with M30 grade concrete and reinforced with Fe415 grade steel as main reinforcement and fibres (steel and banana) as secondary reinforcement. Concrete mixes have been prepared with optimum fibre contents and also without adding fibres (normal concrete). The beams were subjected to cyclic loading in order to evaluate the behavior under simulated earth quake loading conditions. Based on the results of the experimental study significant conclusions were arrived at, to show the behavior of Hybrid Fibre Reinforced Concrete (HFRC) beams is relatively better than that of conventional concrete beams in all aspects. Instead of adding a single type of fibre, the combination of different types of fibres (hybrid fibres) increases the ductility and energy absorption capacity substantially. Thus phenomenon is particularly suitable for structures located in seismic areas.