Effect of hybrid basalt-brucite fiber on the fracture behavior of low-heat cement concrete

The use of mineral fibers in concrete is considered an economically and environmentally friendly measure to improve crack resistance performance. This study focuses on the influence of hybrid basalt-brucite fibers on the fracture performance of low heat cement concrete. The three-point bending test notched beam method was used to study the fracture performance of specimens, including failure mode, peak load, elastic modulus, fracture toughness, and characteristic length. The microstructure of hybrid fibers reinforced low heat cement concrete was explored by combining microscopic testing methods. Results showed that hybrid fibers could significantly change the fracture failure mode of specimens and enhance the bonding properties between aggregates and mortar; With the increase of fiber volume fraction, the elastic modulus, peak load, fracture toughness, and fracture energy of low heat cement concrete were significantly improved; In addition, the hybrid effect brought by hybrid fibers could reduce the brittleness of low heat concrete and increase its toughness. The enhancement mechanism of hybrid fibers on the fracture performance of low heat cement concrete was elucidated; Based on the stress intensity factor method and energy method, the intrinsic relationships between fracture toughness and material strength and fracture energy were explored. The prediction models of fracture parameter of hybrid fiber reinforced low heat cement concrete were established.