High-Strength, Strain-Hardening Cement-Based Composites (HS-SHCC) Made with Different High-Performance Polymer Fibers

Abstract

This article presents an investigation on the tensile behavior of high-strength, strain-hardening cement-based composites (HS-SHCC) made with four different types of high-performance polymer microfibers. In particular, high-density polyethylene (HDPE), poly(p-phenylene-terephthalamide) (aramid), as-spun poly(p-phenylene-2,6-benzobisoxazole) (PBO), and high-modulus PBO fibers were examined in respect of their reinforcing effect in a high-strength, finely grained, cementitious matrix. Moreover, microscopic investigations were carried out to assess the fibers’ ability to be wetted and to explain their interaction with the cementitious matrix. It was shown that the HS-SHCC made with PBO and aramid fibers yielded increased first crack stress and tensile strength, but also a considerably reduced crack width compared to the HS-SHCC reinforced with HDPE fibers. This was traced back to the considerably higher wettability of these fibers compared to the hydrophobic HDPE fibers, ensuring a stronger interfacial bond with the cementitious matrix, but also to their superior mechanical properties, such as tensile strength and Young’s modulus.