Investigation of Impact Resistance of High-Performance Polypropylene Fiber-Reinforced Recycled Aggregate Concrete

In order to investigate the effect of high-performance polypropylene (HPP) fiber on the impact resistance of recycled aggregate concrete (RAC), the impact resistance of HPP fiber-reinforced RAC (HFRAC) was investigated using drop-weight impact equipment and compared with steel fiber-reinforced recycled aggregate concrete (SFRAC). The effects of recycled aggregate replacement rates, fiber content, and fiber type were analyzed. Furthermore, the log-normal distribution and two-parameter Weibull distribution statistical methods were used to fit the probability distribution and predict the failure probability of the initial and final crack impact resistance of HFRAC and SFRAC specimens. The experimental results showed that the impact resistance of RAC decreased with the increase in recycled aggregate replacement rates. HPP fiber had little effect on the impact resistance of initial cracking in RAC, but significantly improved the impact resistance of final cracking in RAC, while steel fiber significantly improved the impact resistance of initial cracking in RAC, but had little effect on the impact resistance of final cracking in RAC. The anti-impact energy consumption and ductility of RAC increased with the increase in HPP content. When the HPP fiber content was 1.25% and the recycled aggregate replacement rate was 50%, the maximum impact energy consumption of RAC was 114.5 times higher than that of the plain RAC concrete specimen, and the maximum ductility ratio of the RAC matrix was 118.3. The addition of HPP fibers significantly improved the impact resistance of RAC. The fitting results showed that the distribution characteristics of HFRAC and SFRAC impact resistance were represented by a log-normal distribution and two-parameter Weibull distribution, with the former presenting a better fit to predict the impact resistance of HFRAC and SFRAC