Shear performance of fibers-reinforced lightweight aggregate concrete produced with industrial waste ceramsite-Lytag after freeze-thaw action

Abstract

Freeze-thaw (F-T) is an environmental hazard to concrete, severely reducing the mechanical properties and durability of concrete structures. The quantitative calculation of the shear performance of lightweight aggregate concrete (LWAC) after F-T action remains obscure. This study performed comprehensive research on basalt (BF)- and polyacrylonitrile fiber (PANF)-reinforced LWACs after F-T action, which can provide the basis for durability design. Compared with plain LWAC, specimens with fiber reinforcement showed a lower reduction in the relative dynamic elastic modulus (RDEM) and shear strength, and the shear strength and length-diameter rate of the fibers were the main impact factors. From the tests, 1.0% BF and 1.5% PANF are suggested as optimal for F-T resistance enhancement. Corresponding models are proposed to predict the changing tendencies of the shear strength, peak shear strain and shear modulus of LWACs after F-T cycles, considering the impact fibers and the environmental parameters. A statistically stochastic model was applied to predict the shear stress-strain curves after F-T action, and the calculation results match the test results well. The evaluation criteria in the standard are unsafe for LWAC F-T durability design. The F-T service life evaluation based on strength degradation could be advantageous in terms of the sustainable development of LWACs in an F-T environment.