A review on alkali-aggregate reactions in alkali-activated mortars/concretes made with alkali-reactive aggregates

Alkali-activated binders are attracting more and more attention as they could potentially be substitutes for traditional Portland cement. Alkali-aggregate reaction (AAR) has been intensively studied for Portland cement-based materials, but much less investigated for the alkali-activated binders. Thereby, precautions should still be made when the alkali-activated binders are used to produce concrete with alkali-reactive aggregates, though many studies have reported that alkali-activated cement-based materials demonstrated better performance than conventional cement-based materials. This paper reviews the research progresses on AAR in mortars and concretes made with alkali-activated binders and alkali reactive aggregates. A variety of factors, such as binders, activators, reactive aggregates are discussed. The applicability of existing testing methods for AAR in alkali-activated binders is also discussed.