An experimental investigation on properties and structural behaviour of hybrid fibrous concrete flexural members

Abstract

Concrete is the most widely used construction material because of its speciality of being cast into any desired shape. The recent developments in concrete technology has resulted in the arrival of new products such as fibre reinforced concrete, high performance concrete, self compacting concrete etc., The main requirements of disaster resistance structures are stiffness, ductility and energy absorption capacity. 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 widening. 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, sisal 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, sisal and banana) as secondary reinforcement. Concrete mixes have been prepared with optimum fibre contents and also without adding fibres (normal concrete newline