Short Carbon Fiber (Csf)-Reinforced Geopolymer Matrix Composites

Short fibers are effective reinforcements in strengthening and toughening geopolymer materials. In this chapter, random-dispersed short carbon fiber (fiber length ≤1 mm) or sheet-like carbon fiber preform (fiber length = 2, 7, 12 mm) was developed as starting materials and are used to prepare geopolymer matrix composites. Mechanical properties, fracture behavior, microstructure, and toughening mechanisms of the as-prepared composites were investigated by three-point bending test, optical microscope, and scanning electron microscopy. Effects of fiber surface treatment and high-temperature treatment on the mechanical properties of the composites were also studied. The results show that Csf/geopolymer composites exhibit apparently improved mechanical properties and an obvious non-catastrophic failure behavior. The predominant strengthening and toughening mechanisms are attributed to the apparent fiber bridging and pulling-out effect based on the weak fiber/matrix interface.