STRUCTURAL PROPERTIES OF CONCRETE COMPOSITE MATERIAL INCORPORATING STEEL FIBRES

摘要

Plain cement concrete is one of the most widely used construction materials as it is with known properties and can be cast to any form and shape. The relatively low tensile strength of plain cement concrete is normally considered as an unavoidable deficiency of the material. Micro-cracks are inherently present in the material which further propagate due to loading, eventually leading to brittle fracture. The micro-cracks appear during volumetric and micro-structural changes at the initial stages of setting and hardening. A discontinuous heterogeneous system thus exist even before the concrete is subjected to external load. On the application of load, initial micro-cracks start developing at about 30 to 40 percent of the ultimate compressive strength and subsequent loading leads to uncontrolled growth of cracks. This phenomenon results in the low fracture toughness and limited resistance to impact and shock loading. This inadequacy led to the innovation of reinforcing the weak matrix with a stiff and strong material to produce a composite of superior properties. Steel fibre reinforced concrete is one of the materials which overcomes a number of shortcomings of plain concrete. It is proposed to discuss the structural properties of concrete composite material incorporating steel fibres.