Mechanical Properties and Durability of Geopolymer Mixes Produced with Hybrid Utilization of Slag, Natural Pozzolan and Waste Soil

The present study investigates the mechanical properties and durability of geopolymer mixtures produced based on pumice natural pozzolan, ground granulated blast furnace slag (GGBFS) and waste soil of aggregate production plants. The aforementioned materials were used in the hybrid form to produce geopolymer. For this purpose, waste soil and pozzolans have been replaced with slag at the levels of 25%, 50% and 75%. The characteristics which have been studied were, compressive strength, flexural strength, sorptivity, rapid chloride ion migration (RCM) coefficient and water absorption content. In addition, different curing conditions were investigated for different mixtures and the results have been compared with each other. The present results indicate that due to the lower reactivity of the natural pozzolan and the waste soil compared to GGBFS, partial replacement of these materials with slag enhanced the mechanical and durability properties, so that the best mixture in terms of durability properties was P25S75. This mix outperformed the S100 mixture in several characteristics. The combined use of GGBFS and the waste soil has also improved the characteristics compared to the mixture with 100% waste soil, which was significantly higher than the promoting effect of GGBFS on the natural pozzolan.