Effect of Freeze-Thaw Cycles on Strength and Toughness Properties of New Generation 3d/4d Steel Fiber-Reinforced Concrete

Abstract

This study aimed to compare the changes in mass loss, relative dynamic modulus of elasticity (RDME), residual compressive strength (RCS), residual flexural strength (RFS), and residual flexural toughness (RFT) of 3D, 4D and 5D steel fiber-reinforced concrete (SFRC) specimens after freeze-thaw (F-T) cycles. 3D, 4D, and 5D steel fibers were added to the concrete mixes at rates of 0.5% and 1.5% by volume. All specimens were subjected to 100, 200, and 300 F-T cycles. The changes in the microstructural properties of control and 3D, 4D, and 5D SFRC samples after F-T cycles were examined with scanning electron microscope (SEM) analysis. According to the test results, 3D, 4D, and 5D steel fibers did not affect reducing mass loss of concrete after F-T cycles. However, 3D, 4D, and 5D SFRC samples had higher RDME, RCS, RFS, and RFT values than control concrete after F-T cycles. Furthermore, 5D steel fibers were more effective than 3D and 4D steel fibers in improving the residual strength and toughness capacity of concrete after F-T cycles due to their stronger fiber/matrix interface. © 2022