ACI PRC-242-22

ACI PRC-242-22 PDF

This report provides a technical overview of alkali-activated cement (AAC) history; chemistry; and mechanical, physical, and durability properties. It also highlights successful case study applications and current technical challenges.

Concrete has traditionally been made with portland cement (PC) binders and PC binders with supplementary cementitious materials, but several emerging alternative cements offer distinctive properties that may be beneficial for some applications (ACI ITG-10.1R). Alkali-activated cements (AACs) are a distinct class of cements that react using alkali activation to form a cement paste solid.

This activation consists of using an alkali- or alkali-salt-based activator to promote the dissolution of an aluminosilicate precursor and subsequent precipitation of cementitious reaction products. Depending on the aluminosilicate precursor (for example, fly ash, ground-granulated blastfurnace slag, calcined clays), alkali activation can initiate a series of either polycondensation reactions, in which water is produced as a result of reaction product formation, or hydration reactions similar to PC, in which water is consumed (Pacheco-Torgal et al. 2014).