Review of Mechanical and Temperature Properties of Fiber Reinforced Recycled Aggregate Concrete

Recycled aggregate concrete has received increasing attention owing to its broad development prospects in recent years. This study discusses the enhancement mechanism of various fibers on the mechanical properties, high-temperature resistance, and freeze-thaw cycle resistance of recycled aggregate concrete. It reviews the effects of fiber types and content on the strength, failure state, and resistance to recycled aggregate concrete's high and low temperatures. The results indicate that fibers can significantly improve the flexural strength and tensile strength of recycled aggregate concrete in the bridging effect but have little effect on compressive strength. Regarding high-temperature resistance, fibers with a lower melting point can form channels in the concrete, reducing the internal pressure of water vapor. Fibers with higher melting points can act as bridges, inhibiting the generation and propagation of cracks in recycled aggregate concrete. Therefore, fiber-reinforced recycled aggregate concrete can perform better at higher temperatures than ordinary recycled aggregate concrete. Due to the high water absorption rate in recycled aggregate concrete, which is approximately 7-10 times that of natural aggregate concrete, it is easier to reach the critical water saturation of freeze-thaw damage. Results show that 0.2 kg/m(3) polypropylene fiber and 1.2 kg/m(3) basalt fiber show excellent performance in improving the frost resistance of recycled aggregate concrete.