Synthesis of polypropylene fiber/high-calcium fly ash geopolymer with outdoor heat exposure

Solar energy is an important source of renewable and sustainable energy. Thailand is near the equator and thus experiences hot weather throughout the year. The average maximum temperature is 35 °C and can reach 40 °C in the summer time. This outdoor heat exposure (OHE) was, therefore, used for the curing of a polypropylene (PP) fiber fiber-reinforced high-calcium fly ash geopolymer composite, in order to reduce energy consumption. Fly ash is an abundant solid waste generated from the coal-power generation process. In this research, a high-calcium fly ash was used as a source material for the geopolymer synthesis. PP fiber was also incorporated in the composites to improve tensile characteristics and control crack development. The results show that the incorporation of PP fiber in composites led to improved tensile strength, crack control, and resistance to acid solution. OHE could thus be used as an energy source for the heat curing of high-calcium fly ash PP-fiber geopolymers, resulting in a strong matrix.