Experimental study on compression failure characteristics of basalt fiber-reinforced lightweight aggregate concrete: Influences of strain rate and structural size

This paper presents systematic experimental investigations on the combined influences of loading strain rate and structural size on uniaxial-compression failure characteristics of LAC and basalt fiber-reinforced lightweight aggregate concrete (BFLAC), in terms of workability, failure morphology, deformation curve, failure strength, elastic modulus and energy absorption, with a special focus on the size-dependence of strain rate effect. Results indicate that the uniaxial-compression strength, elastic modulus, compression toughness as well as specific toughness are increased when the basalt fibers with 0.3% volume content is added in LAC, which can be ascribed to the synergistic effect of three working modes of basalt fibers in restricting the crack propagation and fracture failure. As the strain rate increases, specimens with larger size perform a stronger strain rate effect, resulting in that the influence of structural size on uniaxial-compression failures is weakened. The addition of basalt fibers can also weaken the size-dependence on uniaxial-compression strength, compression toughness and specific toughness, which contributes to the promotion and application of basalt fibers in LAC, especially for large-scale engineering structures. The dynamic increase factor (DIF) empirical formulas of LAC and BFLAC with various structural sizes have been obtained, which can provide a reasonable reference for structure safety design and numerical computation of LAC and BFLAC.