Production of carbonated superhydrophobic cementitious composites for enhanced environmental stability and abrasion resistance

Multiscale hydrophilicity in cementitious materials makes buildings vulnerable to the penetration and erosion effects of external water and inorganic ions, significantly reducing the durability and safety of concrete structures. Superhydrophobic materials, known for their excellent water repellency, effectively mitigate these issues. However, conventional superhydrophobic materials often suffer from surface flaking and poor robustness in practical applications. To address this, a novel and sustainable method for preparing superhydrophobic cementitious composites (SHCCs) was developed, based on the binary synergistic action of in situ carbonated fly ash with a micro- and nano-composite structure through carbon dioxide mineralisation technology, combined with fluoroalkylsilane, which has low surface energy. The resulting SHCCs demonstrated exceptional water repellency, with no significant reduction in superhydrophobicity after sandpaper abrasion and extreme cyclic temperature exposure. These key properties enhance the longevity of hydraulic structures, marine buildings and constructions in extreme environments.