Dynamic Mechanical Properties of PVA Fiber-Reinforced Concrete after Freeze-Thaw Cycles

ABSTRACT Concrete structures have been employed in a multitude of low- and even ultra–low-temperature environments, necessitating that these structures exhibit a certain degree of impact and explosion resistance in addition to the capacity to withstand the elevated temperatures induced by the low-temperature environment and the additional load. In this study, the dynamic mechanical properties of polyvinyl alcohol (PVA) fiber-reinforced concrete were investigated under freeze-thaw cycles at temperatures ranging from 20°C to −70°C. The research employed a split-Hopkinson pressure bar with a diameter of 75 mm. The findings revealed that the PVA fibers were randomly dispersed within the concrete matrix, exhibiting a superior bridging effect, effectively supporting the tensile stress generated by the impact. The impact toughness of concrete exhibited a biphasic response to the addition of PVA fiber admixture. Initially, the toughness increased with increasing fiber content, reaching a peak at 1.2 kg/m3. Subsequently, the toughness decreased with further increases in fiber content. The incorporation of PVA fibers significantly enhanced the energy absorption capacity of the concrete at freeze-thaw cycles between 20°C and −70°C.