Effect of steel fibres on concrete at different temperatures in terms of shear failure

Abstract

This paper experimentally investigated the behaviour of concrete at elevated temperatures in terms of shear deterioration using steel fibres. Forty five specimens of push-off model were used in which three samples for each category of maximum temperatures. Five maximum temperatures have been investigated i.e. 20, 150, 300, 500 and 700 °C. The main objective of this research is to investigate the effect of steel fibres on the behaviour of concrete at different maximum temperatures in terms of shear failure. This study showed the enhanced ductility and strength of the shear at elevated temperatures. Three main categories have been tested: plain concrete, steel fibre contents of 40 kg/m³ or 80 kg/m³. In addition, both crack width and crack slip have been measured using means of linear variable differential transducers (LVDTs). Results showed that the content of steel fibres increases the shear strength at ambient temperature by 103% and 102% for both SFRC-40 and SFRC-80, respectively. Although this enhancement is less important at high temperatures, i.e., 500 and 700 °C, still the mixes that contain fibres have higher residual shear strengths than plain mixes. Moreover, steel fibres content is affecting ductility in both ambient and high temperatures.