Performance Degradation of Fiber-Reinforced Concrete under Freeze–Thaw Cycles and Its Resistance to Chloride Ion Penetration

Abstract

This study investigated the frost resistance of fiber-reinforced concrete with different contents of polyvinyl alcohol (PVA) fiber under freeze–thaw cycles, and the resistance to chloride penetration. The freeze–thaw cycle experiment was carried out using the rapid freeze–thaw method. Mass loss, relative dynamic modulus of elasticity, compressive strength, and flexural strength were investigated, and the influence of chloride ion content and the chloride ion diffusion coefficient after freeze–thaw cycles was analyzed. The results showed that under freeze–thaw cycles, PVA fiber can effectively reduce mass and dynamic elastic modulus loss and improve compressive and flexural strength. The contributions of fiber to mass loss, relative dynamic elastic modulus, and compressive strength gradually decreased with the addition of PVA fiber (>0.12 vol. %), while the contribution to flexural strength increased. The penetration depth of chloride ions positively correlated with the number of freeze–thaw cycles. The PVA fiber-reinforced concrete exhibited better chloride ion penetration resistance compared with that of the control concrete after freeze–thaw cycles. The concrete mixed with 0.12 vol. % PVA fiber exhibited the best chloride ion penetration resistance.