Dynamic mechanical behavior of steel fiber reinforced-recycled aggregate concrete subjected to uniaxial loading

The objective of this study was to investigate the dynamic mechanical performance of steel fiber reinforced-recycled aggregate concrete (SFRAC) under uniaxial loading. A total of 22 groups of cylindrical samples, each measuring 100 mm × 200 mm, were subjected to uniaxial compression. The investigation placed particular emphasis on examining the influence of variables such as the strain rate, volume fraction of steel fiber (Vsf), volume fraction of polyvinyl-alcohol (PVA) fiber (Vpf) and substitution ratio of recycled coarse aggregate (SRCA) on the failure modes, stress-strain curves and deformation ability. The results revealed that the incorporation of steel fibers and PVA fibers enhanced the overall integrity of fractured samples, and induced changes in the failure modes. In particular, the maximum increase in uniaxial compressive strength attributed to strain rate, Vsf and Vpf reached up to 15.0%, 23.57% and 8.57%, respectively. Although the inclusion of recycled aggregates had no significant influence on the failure mode, it decreased the compressive strength by up to 16.34%. Finally, a dynamic stress-strain theoretical constitutive model was established in this paper. The predictions derived from this model closely aligned with the experimental stress-strain curves obtained during the conducted tests. This study provides valuable insights for applications of SFRAC in structural engineering.