Investigation of bond between lap-spliced steel bar and self-compacting concrete: The role of silica fume

Abstract

In this study, normal concrete (NC) and four types of self-compacting concrete (SCC), in which cement was partially replaced by 5%, 10%, 15%, and 20% of silica fume (SF), were used to evaluate the effect of SF content on the bond strength of tension lap-spliced bars embedded in NC and SCC specimens. Therefore, 15 full-scale beam specimens (2000 × 300 × 200 mm3) were tested and 20 mm reinforcing bars were used with a 300-mm splice length as tension reinforcement. Each beam was designed with bars spliced in a constant moment region at midspan. It was found that the bond strength of the reinforcement embedded in SCC beams was higher than that of the reinforcement in NC beams, whilst the bond strength increased with increase in the replacement of cement by SF from 5% to 10%. Moreover, the beam specimens produced from SCC containing 5% SF had the highest normalized bond strength of 1.07 followed by SCC beams with 10% SF, 15% SF, NC beams, and 20% SF.