Long-term durability properties of geopolymer concrete: An in-depth review

Geopolymer concretes (geocretes) are considered as eco-friendly materials for various building applications. Geocrete has high early strength, less consumption of natural resources, cost-effectiveness, capacity to form different structural configurations and to remain intact for extended periods without repair works. Meanwhile, geocretes have still exhibited an unstable behavior over time compared to traditional cementitious composites. To overcome this disadvantage, hundreds of studies have focused on the improvement of the microstructure of geocretes with a wide range of improved durability characteristics. Therefore, the review paper has an objective to make available an inclusive review on the production of supplemental-cementing-materials (SCMs), their economic returns, environmental and durability impacts, the conceptual model for geopolymerization, durability affecting factors, and function and long-term durability properties of geocrete. It is concluded that geocrete demonstrated a better resistance against aggressive environment compared to normal concrete, due to its less porous structures. Moreover, it is found that the strength of alkali-activated concrete was found to improve in chloride environment, unlike OPC based concrete. It is also concluded that, the presence of GGBS and MK in alkali-activated materials reduces its alkali-silica reactivity while it is recommended to use high calcium FA in geocrete production for durable concrete and geopolymerization. The higher the molarity of NaOH solution for a given quantity of Na₂SiO₃ the faster the geopolymerization process and the higher the compressive strength of concrete corrosion current than the OPC concrete. Further long-term durability studies are required to provide test methods and validation techniques since most studies focus on the 28-day curing regime.