The present study investigates the synthesis of mesoporous geopolymers containing different nanocrystalline
zeolite phases. A hydrothermal treatment procedure was utilized to synthesize the mesoporous
geopolymers using fly ash, slag and alkaline solution. The effects of slag addition and molar ratio
of alkaline solution on the microstructure and mechanical strength of the geopolymers were investigated
and evidenced by XRD analysis, compressive strength and nitrogen adsorption tests. The test results
showed that the geopolymers incorporating fly ash and slag consisted of Na-P1 and Sodalite zeolite
phases, and had the characteristic of mesoporous materials (2 nm < pore size < 50 nm) in which capillary
condensation may occur. The highest compressive strength of the geopolymers was 16.57 MPa, and the
desired mesoporous characteristics were met by adding 20% slag content to fly ash and adopting the
hydrothermal process at a relatively low temperature. The highest BET surface area and single point
adsorption pore volume of the mesoporous geopolymers were 114.16 m2/g and 0.2677 cm3/g,
respectively.