One-part slag/zeolite geopolymer mortars under ambient and heat curing conditions

Geopolymer materials can be formulated with a variety of precursors rich in aluminosilicates. However, some of these precursors, which are industrial by-products, are not widely available in the world. Therefore, there is a need to explore alternative potential precursors derived from natural sources. This study investigates the viability of using natural zeolite utilization as a part of the precursor in one-part ground granulated blast furnace slag (GGBFS)-based geopolymer mortars activated with sodium metasilicate. Geopolymer mortars were made with 0-90 wt% natural zeolite and cured at ambient and 40 celcius temperatures. Fresh and hardened properties were evaluated. The test results showed that zeolite addition reduced the workability and setting time of the fresh mortar, significantly. Furthermore, the mechanical strength dropped with increasing zeolite content due to the microporous structure of the zeolite particles and weak reaction products. The microstructural examination showed that the mortars containing zeolite had a more porous structure compared to the pure slag mortar. Furthermore, heat-curing increased the mechanical strength in all mortars and densified the microstructure.