Effect of accelerated freeze-thaw cycling on mechanical properties of hybrid PVA and PE fiber-reinforced strain-hardening cement-based composites (SHCCs)

In this study, the influence of rapid freezing and thawing actions on mechanical properties of hybrid fibers reinforced strain-hardening cement-based composites (SHCCs), which exhibit multiple cracking and strain-hardening behavior in direct tension, were investigated. Four SHCC mixtures with different water-to-binder (W/B) ratios and hybrid fiber combinations were assessed experimentally. The SHCC mixtures incorporating hybrid polyvinyl alcohol (PVA) and ultra-high molecular weight polyethylene (PE) fibers at the 1.5% volume fraction were exposed to freezing and thawing according to ASTM C 666 (Procedure B). The freeze-thaw tests continued until the specimens achieved 300 freeze-thaw cycles. The results of these tests indicate that rapid freeze-thaw cycles in the laboratory have little effect on the compressive and tensile strength characteristics of the SHCC mixtures prepared in this study, whereas multiple cracking behavior and deformation capacity of SHCC specimens under direct tensile and flexural loadings indicate that freeze-thaw cycles have a negative effect on the these characteristics of the SHCC mixtures. A tendency toward reduced ductility is prominent for SHCC materials with higher W/B ratio and more hydrophilic PVA fiber.