Mechanical behavior of fiber-reinforced lightweight concrete subjected to repeated freezing and thawing

This paper presents the results of a study on the influence of steel fiber and of polyvinyl alcohol (PVA) fiber on the mechanical properties of lightweight concrete (LC) exposed to freezing and thawing cycles. The LC (with and without fibers) samples were subjected to different numbers of freeze–thaw cycles (0, 150, or 300) according to the requirements of ASTM C 666. The differences of the compressive strength, flexural strength and direct tensile strength of the specimens were measured after selected number of freeze–thaw cycles. Before being subjected to the selected number of freeze–thaw cycles, the samples were prepared either by being frozen and thawed, or by being air-dried. After the 28-day standard curing procedure (i.e., 0 freeze–thaw cycles), the LC and FRLC specimens were placed in a chamber and exposed to 150 (80 days) or 300 (130 days) freeze–thaw cycles. The air-dried concrete specimens were cured in air and tested on the same days as the specimens subjected to freeze–thaw cycles. The deterioration of the strength of the LC and FRLC specimens subjected to the experimental freeze–thaw cycles were explored through air-dried specimens. The results have shown that the application of fibers increased the compressive, flexural, and direct tensile strength of the air-dried specimens. Moreover, the FRLC was found to be more resistant to cracking and to freeze–thaw damage than concrete without fibers. The FRLC produced with 1.25 vol% PVA fiber showed better strength than with 0.25 vol% steel fiber.