Experimental evaluation of fracture toughness of basalt macro fiber reinforced high performance lightweight aggregate concrete

Abstract

High performance lightweight aggregate concrete has become a popular topic for the development of green concrete due to the incorporation of various industrial wastes to substitute aggregate. However, its brittleness has gradually emerged as an issue with the increasing of compressive strength. To address this concern, the authors in this paper investigated the influence of basalt macro fiber (BMF) on the compressive and splitting tensile strengths of lightweight aggregate concrete at different fiber volume contents and lengths. Moreover, the three-point bending test on notched beams, with the help of acoustic emission and digital image correlation, was also carried out to evaluate the fracture toughness of basalt macro fiber reinforced lightweight aggregate concrete. Finally, the softening constitutive model was determined in the present study. The results showed that the addition of BMF increased the compressive strength of lightweight aggregate concrete and the maximum increase reached 9.03%. As for splitting tensile strength, the maximum increase was 39.88%. In addition, it was observed that the incorporation of basalt macro fiber significantly improved the initial cracking toughness and unstable fracture toughness of plain specimen. The fracture energy of BMF reinforced lightweight aggregate concrete was also increased, and the largest improvement was seen in BMF-0.5–22.5 group, 8.5 times that of plain specimen.