Bond behaviour of deformed bars in self-compacting lightweight concrete subjected to lateral pressure

Abstract

The purpose of this paper is to present an experimental investigation into the bond behaviour between deformed bars and self-compacting lightweight concrete (SCLC) under lateral pressure. SCLC pull-out specimens made with two types of lightweight aggregate were tested under two orthogonal lateral pressures p1 and p2, perpendicular and parallel to the transverse rib of deformed bars respectively. It was found that, under uniaxial lateral pressure, the ultimate bond stress increases with an increase of p2 but is independent of p1. Under biaxial lateral pressures, the ultimate bond stress increases monotonically with an increase in p1 and/or p2. The slip at the ultimate bond stress is an increasing function of lateral pressure for specimens failing by splitting, but basically remains constant for specimens failing by pull-out. The ratio of residual to ultimate bond stress is mainly related to the ratio of cover depth to bar diameter. It was also found that the lightweight aggregate type has little influence on the bond behaviour of deformed bars. Based on the experimental results, empirical formulae for the ultimate bond stress, the slip at the ultimate bond stress and the ratio of residual to ultimate bond stress are formulated. Finally, a bond stress–slip model is proposed and verified with experimental results.