Effects of Strain Rate and Fiber Content on the Dynamic Mechanical Properties of Sisal Fiber Cement-Based Composites

Abstract

In this paper, a split Hopkinson pressure bar (SHPB) was used to investigate the dynamic impact mechanical behavior of sisal fiber-reinforced cement-based composites (SFRCCs), and the microscopic damage evolution of the composites was analyzed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrome-try (EDS). The results show that the addition of sisal fibers improves the impact resistance of cement-based composite materials. Compared with ordinary cement-based composites (OCCs), the SFRCCs demonstrate higher post-peak strength, ductility, and energy absorption capacity with higher fiber content. Moreover, the SFRCCs are strain rate sensitive materials, and their peak stress, ultimate strain, and energy integrals all increase with increasing strain rate. From the perspective of fracture failure characteristics, the failure of OCCs is dominated by the brittle failure of crystal cleavage. In contrast, the failure mode of the SFRCCs changes to microscale matrix cracks, multi-scale pull-out interface debonding of fibers (fine filaments and bundles), and mechanical interlock. This research provides an experimental basis for the engineering application of high-performance and green cement-based composites.