Durability and CO2 sequestration capacity of carbon sequestration foamed concrete under magnesium and sodium sulfate attacks

Carbon sequestration foamed concrete (CFC) is primarily composed of MgO, serpentine, silty clay, water and carbon dioxide (CO 2 ) foam. CFC has been extensively studied in previous literature for its exceptional performance in CO 2 sequestration. However, the lack of studies on the durability of CFC under sulfate attack remains a significant challenge for its large-scale application as a building material. This study investigated the durability and CO 2 sequestration of CFC under chemical sulfate attack by evaluating the changes in specimen volume, mass, phase identification and CO 2 sequestration capacity. The CFC specimens were exposed to magnesium sulfate (MgSO 4 ) and sodium sulfate (Na 2 SO 4 ) solutions for 10, 20 and 30 days, respectively, after which a series of tests were conducted. The results indicate that CFC exhibits enhanced sulfate resistance when exposed to MgSO 4 and Na 2 SO 4 solutions. The findings provide a foundation for improving the durability of foamed concrete under harsh environmental conditions. • Sulfate attack slightly alters hydration–carbonation but preserves pore integrity. • Mg 2+ supply facilitates hydrated magnesium carbonates formation under attack. • CO 2 sequestration capacity remains stable under MgSO 4 and Na 2 SO 4 exposures.