A Review of Recent Advances in Alkali-activated Materials from Silica-rich Wastes Derived Sodium Silicate Activators

Abstract

Sodium silicate activators derived from silica-rich wastes have attracted increasing attention owing to their promotion on the sustainable production and development of alkali-activated materials (AAM). This paper presents the research progress on the feasibility of using silica-rich wastes-derived sodium silicate activator as an alternative to commercial sodium silicate activator in AAM. The basic factors affecting the quality of silica-rich wastes-derived sodium silicate activator are reviewed. The structure features between commercial sodium silicate and derivative sodium silicate are addressed and compared. Influences of the two different sodium silicates on flowability, mechanical properties, microstructure and durability are summarized and discussed. Previous studies reveal that utilizations of amorphously rich SiO2 containing materials, together with proper preparation technology, enable to produce highly reactive sodium silicate activators and as a consequence to obtain materials with comparable or even better performances as compared to the commercially available sodium silicate-AAM. Recommendations for future investigation are provided eventually.