Tensile Response and Fracture Process of High-Performance Hybrid Fiber-Reinforced Cement Composites

摘要

Five twisted steel fibers (steel cord, SC) are used to improve the post-cracking behavior of cement composites. In addition to these steel cord macrofibers, microfibers are used to enhance the pre- and post-cracking strength and behavior. The three specific hybrid fiber blends pursued in this investigation are SC and polyethylene (PE), SC and polypropylene (PP) as well as SC and polyvinyl alcohol (PVA) fibers. The research results show that SC macrofibers with high ultimate strain, strength and bond stress can bridge the macrocracks in the matrix. Therefore, cement-based composites reinforced with SC fibers exhibit a pseudo-strain hardening in tension as a result of the formation of multiple cracks. The microfibers improved pre-peak mechanical performance, strength, and fracture process by delaying the formation of a macrocrack. The tensile strength, energy consumption capacity and ductility of SC macrofibers and high elastic modulus microfiber PE reinforced cement-based composites are tremendously improved compared to SC macrofibers with lower elastic modulus microfibers PVA and PP.