Adding an expansive agent to increase the toughness of steel fibre reinforced concrete

Abstract

Previous research studies have indicated that using fibres to improve crack resistance and applying expansive agent (EA) to compensate shrinkage are both effective methods to mitigate shrinkage cracking of concrete, and the additions of both fibres and EA can enhance the other performance attributes of concrete. In this study, an EA was added to fibre reinforced concrete (FRC) to produce concrete mixes with various water/binder (W/B) ratios, steel fibre (SF) contents and EA contents for testing of their workability and compressive properties. The test results showed that adding EA would slightly increase the superplasticiser (SP) demand and decrease the compressive strength, Young’s modulus and Poisson’s ratio, but significantly improve the toughness and specific toughness of the steel FRC produced. Such improvement in toughness may be attributed to the pre-stress of the concrete matrix and the confinement effect of the SFs due to the expansion of the concrete and the restraint of the SFs against such expansion.