Nano-SiO2 modified basalt fiber for enhancing mechanical properties of oil well cement

In this paper, the surface of basalt fiber (BF) was roughened with glacial acetic acid solution (HAc), and then modified with bis(trimethoxysilylpropyl) ammonia. Finally, nano-silica was loaded on the fiber surface for modification by hydrolysis of tetraethyl orthosilicate (TEOS). The composition and microstructure of basalt fiber were characterized by FT-IR, AFM, SEM, XPS, and EDS. The effect of the modification of basalt fibers on the mechanical properties of oil well cement was studied. The flexural strength of the cement stone added with modified basalt fibers was increased by 37.5% and 27.3% compared with that of blank cement stone and unmodified basalt fiber cement stone after 28 days of curing at 80 °C under normal pressure, respectively. Fiber monofilament pull-out experiments and SEM analysis showed that the nano-silica on the surface of basalt fibers can improve the bond strength between the fibers and the cement matrix, thus enhancing the bridging effect of basalt fibers in the cement matrix and finally improving the mechanical properties of cement stone. • Basalt fiber is a green, environmentally friendly toughening agent. • The nano-SiO2 is successfully bonded to the surface of basalt fibers. • The nano-silica on the surface of basalt fiber improves the roughness of the fiber surface physically. Chemically, C ~ S ~ H is formed by hydration reaction with cement, which enhances the bonding degree between fiber and cement matrix and thus improves the mechanical properties of oil well cement stone.