Study of the Flexural Strength of RC Beams using Slag as a Replacement of Coarse Aggregate in the presence of Steel Fibers

Abstract

This study focuses on the use of steel slag as a percentage replacement of natural-weight coarse aggregate in concrete to study already established assessment parameters. Disposal of slag is a major concern for steel manufacturing industries. This effort will pave way for the conservation of natural aggregate by using steel slag in concrete with enhanced performance properties. Steel fibers are also added into the concrete matrix to reduce its brittle nature. This addition causes a reduction in the micro-cracking and localized macro-cracking, with improved post-cracking strength and ductility since the crack propagation is slow in the presence of steel fibers due to the bridging effect provided in any direction a crack might propagate. The study constitutes the assessment of parameters, such as compressive strength (f’c), Modulus of Elasticity (Ec), Stiffness Index, Toughness Index and energies dissipated for various replacement percentages (40%, 50%, 60% and 100%). The same replacement percentages are then used to cast scale-down structural beams for the assessment of flexural strength. Use of slag in concrete enhances the strength due to a major improvement of the ITZ (inter-transition zone) that is the bond between mortar and aggregate is relatively stronger due to high surface roughness of the slag aggregate.