Durability of one-part geopolymer concrete in aggressive environments

One-part geopolymer concrete (GPC), developed based on the “just-add-water” concept, can be cast in a manner similar to ordinary Portland cement (OPC) concrete. However, limited research has been conducted on its durability in aggressive environments. In this study, one-part GPC samples, along with control OPC concrete and two-part GPC samples (using an activator solution), were prepared and exposed to 2 % sulphuric acid, 5 % sodium chloride, and 5 % sodium sulphate solutions for up to one year. The one-part and two-part GPC samples, both cured at ambient temperature, were prepared using fly ash/slag ratios of 77/23 and 91/9 wt%, respectively. All three types of concrete achieved comparable compressive strengths at 28 days (37.1–42.6 MPa). This study analysed the visual appearance, mass change, compressive strength, and microstructural properties. The test results revealed that OPC concrete exhibited the lowest durability in acidic and sulphate environments compared to the other two types of concrete. In acidic environments, the two-part GPC demonstrated slightly better durability than the one-part GPC, whereas in chloride conditions, the one-part GPC outperformed the two-part GPC. After long-term sulphate exposure, the strength retention capacities of the two types of GPC were comparable. Overall, the study demonstrates that the one-part GPC offers superior durability compared to OPC concrete in all tested environments, highlighting its potential for widespread use in aggressive environments.