Leaching and efflorescence of alkali-activated slag materials: A multi-scale experimental and simulation study

Alkali‐activated slag (AAS) materials, composed of blast furnace slag as precursor and alkali solutions as activators, are emerging as sustainable alternatives in construction due to their significantly lower CO₂ emissions compared to traditional Portland cement (PC) ‐based materials. These cement‐free binders often demonstrate comparable or even superior mechanical properties and chemical resistance. However, long‐term durability remains a concern, particularly in humid environments where AAS materials are more susceptible to degradation than PC materials.

Leaching has been identified as the primary deterioration phenomenon in AAS materials under humid environments, yet the underlying mechanisms remain poorly understood. Additionally, efflorescence, characterised by white deposits on the material surface, is believed to be a consequence of leaching. However, the relationship between leaching and efflorescence in AAS materials remains unclear, necessitating further investigation. This thesis aims to bridge these knowledge gaps by investigating the leaching behaviour of AAS materials at multiple scales and developing effective strategies to mitigate efflorescence....