Performance evaluation of high-strength concrete reinforced with basalt fibers exposed to elevated temperatures

Abstract

This study experimentally investigated the effectiveness of the inclusion of basalt fibers in concrete to enhance the performance of the concrete components when exposed to elevated temperatures. Concrete specimens were reinforced with basalt fibers at dosages of 0.25%, 0.5%, 0.75%, and 1%, and then exposed to high temperatures of up to 600 °C. Chopped basalt fibers act as fillers and bridge the gaps and micro-cracks within concrete, resulting in the high strength and energy absorption capacity of basalt fiber-reinforced concrete. At elevated temperatures, when the surface-bound water becomes evaporated, additional stress was found to be released through the softening of basalt fibers. Moreover, at such high temperatures, basalt fibers held the aggregates and cement paste in position by gripping the macro-cracks when the hydration products of concrete began to decompose. The residual strength in fiber-reinforced concrete was thereby significantly higher than that in non-fibered concrete. However, beyond the optimum level of fiber addition, agglomeration, and the non-uniform dispersion of fibers was observed, which results in the lowered performance of the concrete.