Short SiC Fiber and Hybrid SiC/Carbon Fiber Reinforced Geopolymer Matrix Composites

Although short carbon fiber-reinforced geopolymer composite exhibited good mechanical properties, it is well recognized that carbon fiber is susceptible to be oxidized to CO₂ at a temperature as low as 500 °C in air atmosphere, which is detrimental to the mechanical performance of the composites when it is exposed to high temperature in air. SiC fiber showed similar mechanical performance with carbon fiber but much higher oxidation resistance, and it can retain 80% room-temperature strength even at 1200 °C in air, which makes it a prominent high-temperature reinforcing candidate. In this chapter, both short SiC fiber and hybrid short SiC and carbon fiber-reinforced geopolymer composites were prepared, and the effects of both fiber contents and fiber length on the microstructure, interfacial state, mechanical properties, and fracture behavior of the composites were systematically reported.