Durability of alkali-activated materials in aggressive environments: A review on recent studies

Corrosion of reinforcement and concrete deterioration induced by aggressive media could severely reduce the bearing capacity of structures. The durability of alkali-activated materials (AAMs) in aggressive environments, such as carbonation, chloride penetration and sulfate attack, have been a research focus worldwide. Reaction products and microstructures of AAMs are different from ordinary Portland cement (OPC), therefore the corrosion mechanisms and assessments are different. This paper reviews factors influencing water absorption and permeability of AAMs, effect of gel composition and exposure environments on carbonation, chloride penetration and chloride migration test methods, and sulfate resistance in high-calcium and low-calcium alkali-activated systems. There remains a large space in these aspects to completely understand the deterioration of AAMs, as pointed out in the end. The perspectives suggested in this paper will be useful for future study on long-term durability of AAMs.