Effect of different fiber sizing on basalt fiber-reinforced cement-based materials at low temperature: From macro mechanical properties to microscopic mechanism

Abstract

The interfacial bonding performance between basalt fiber bundles with three type of sizing agent and cement-based materials at different curing environment was studied through analyses on pull-out tests and scanning electron microscope (SEM) results. The mechanical development law of three type of basalt fiber reinforced concrete (BFRC) was studied through analyses on mechanical property tests and computed tomography (CT) results and theoretical analysis of molecular structure. It is concluded that: (1) The low-temperature environment significantly deteriorates the bonding properties of the basalt fiber and the cement mortar. The effect of bonding strength of basalt fiber cement mortar (BFCM) specimens with different fiber sizing agents differs significantly: dispersed type > flexible type > cluster type; (2) The SEM micro-morphology and CT scanning analysis show that the type of sizing agent affects the optimal volume dose of basalt fiber in concrete. Besides, the type of sizing agent affects the formation and development of the interface transition zone between the fiber and the cement matrix. (3) The differences in the molecular structure of the sizing agents have a significant effect on the interfacial properties of the basalt fiber-cement matrix, in which sizing agent containing KH560 component is better for the interface improvement between fiber and cement matrix. Large molecular weight epoxy resins may reduce the surface roughness of the basalt fiber sizing agents.