Abstract: The high temperature mechanical properties of the normal concrete(NC), the basalt fiber reinforced concrete(BFRC)and nano-SiO₂ basalt fiber reinforced concrete(NBFRC)were investigated, such as the compressive strength, splitting tensile strength, flexural strength, and so on. The results show that the compressive strength, splitting tensile strength and flexural strength of NBFRC are higher than those of BFRC and NC at each temperature. At 400 ℃, the compressive strength of the three kinds of concrete reaches the maximum, and then decreases gradually, and the splitting tensile strength and flexural strength decrease with the increase of temperature. Compared with NC, the compressive strength, splitting tensile strength, flexural strength of NBFRC increase by 13.2%, 22.9%, 13.2%, respectively, at room temperature, and by 12.4%, 23.3%, 21.9%, respectively, at 400 ℃. At 800 ℃, the strength of three kinds of concrete reaches the lowest, and the compressive strength, splitting tensile strength and flexural strength of the NBFRC are only 47.8%, 29.1% and 35.5% at room temperature. NC, BFRC and NBFRC relative strength prediction model is accurate.

Key words: concrete, basalt fibers, nano SiO₂, high properties, prediction model, composites