Properties of Geopolymer Composites Reinforced with Basalt Chopped Strand Mat or Woven Fabric

Geopolymers or polysialates are inorganic polymeric, ceramic-like materials composed of alumina, silica, and alkali metal oxides that can be made without any thermal treatment. Additions of reinforcing phases vastly improve the mechanical properties and high-temperature stability of the geopolymer. The processing and mechanical properties of both chopped strand mat as well as 2-D woven fabric-reinforced potassium geopolymer composites have been evaluated. Hand lay-up and hydraulic press processing methods were used to produce composite panels. The room-temperature tensile and flexural strength of chopped strand mat composites was 21.0 ± 3.1 and 31.7 ± 4.4 MPa, respectively, while those of basalt weave-reinforced geopolymer composites reached 40.0 ± 5.9 and 45.2 ± 9.3 MPa, respectively. Composite microstructures were examined using optical microscopy as well as scanning electron microscopy (SEM). Mass, volume, and porosity fractions were also determined. The effect of high-temperature treatments at 25°C, 300°C, 600°C, and 800°C were analyzed. Finally, Weibull statistical analysis was performed, which showed an increase in reliability when a reinforcement phase was added to K-geopolymer.