Effect of steel fibres on shear strength of geopolymer concrete beams

Abstract

This paper deals with an experimental investigation on the effect of steel fibres on the shear strength of Geopolymer concrete (GPC) beams. Tests were conducted on 10 reinforced beams of 100x150x1200 mm size. The shear span to effective depth ratio is fixed as 3. The Geopolymer concrete was designed by trial and error method, for a compressive strength of 40 MPa as per the guidelines given by Rangan. The variable considered in this study is the volume fraction of steel fibres, viz; 0.25, 0.50, 0.75 and 1% respectively. Crimped steel fibres having a diameter of 0.45 mm and an aspect ratio of 66 were used. It is observed from the test results that, as the volume fraction of fibres increases, the ultimate shear strength also increases and the failure mode changed from shear to flexure. An attempt was made to predict the shear strength of steel fibre reinforced geopolymer concrete (SFRGPC) using the equations available in literature for conventional fibre reinforced concrete. As the predictions were not satisfactory, a new method was proposed to predict the ultimate shear strength of SFRGPC.