Bond properties between concrete and high ductility cementitious composite with totally recycled fine aggregate

In order to explore the potential of high ductility cementitious composite with totally recycled fine aggregate (RHDCC) as building repair material, the bond properties between concrete and R-HDCC were investigated through the double-face shear test in this study, which could be helpful for promoting the recycling of waste concrete, reducing environmental pollution and attaining better repair efficiency. The effects of concrete compressive strength, R-HDCC compressive strength and fiber volume fraction of R-HDCC on the bond properties between concrete and R-HDCC were analyzed in detail, and compared with those between concrete and high ductility cementitious composites with natural fine aggregate (N-HDCC). The acoustic emission technique was employed to monitor the internal damage of specimens, and the obtained signals were used as basis for analyzing the load bearing process. The experimental results showed that concrete/R-HDCC bonding specimen performed a higher bond strength and ductility than concrete/N-HDCC due to the tighter bond interface. The bond stress and slip at peak points on the bond stress-slip curve of concrete/R-HDCC specimens increased with the increasing of concrete compressive strength, R-HDCC compressive strength and fiber volume fraction of R-HDCC, while the bond stress at ultimate point decreased with the increasing of fiber volume fraction due to the larger slip and energy produced by more fibers pulled-out. Finally, the trilinear bond stress-slip model applicable to concrete/R-HDCC bonding specimen was established based on the statistical analysis of experimental results.