Mechanism of KH550 Improving Basalt Fiber Cement-Based Interface and Mechanical Properties

To enhance the interfacial bonding capacity between basalt fiber and cementitious matrix, and to maximize the efficacy of basalt fiber in augmenting toughness, fracture resistance, and flexural strength within the cementitious matrix, the basalt fiber underwent treatment using a solution of γ-amino propyl triethoxy silane (KH550). Employing a single-fiber electron tensile testing instrument, the fracture strength and fracture elongation of basalt fibers were examined under various treatment conditions, leading to the determination of the optimal treatment concentration and immersion time. Subsequently, the scanning electron microscope (SEM) and energy-dispersive spectroscopy (EDS) were employed to investigate the surface morphology and elemental composition of the self-assembled molecular coating on the basalt fibers. Lastly, the UTM universal testing machine was utilized to subject concrete beams to loading, while the XTDIC digital speckle correlation full-field strain measurement system was employed to analyze strain conditions and crack propagation throughout the loading process. The experiments indicate that the KH550 system solution can spontaneously generate a fish-scale-like coating on the basalt fibers, thereby enhancing the interconnection between basalt fibers and cementitious materials, optimizing the role of basalt fibers in enhancing toughness and flexural resistance within cementitious materials, and retarding the initiation and development of concrete cracks.