Investigation of Potential Alkali–Silica Reaction of Different Types of Aggregate in Mortar with and Without Fly Ash

This study investigates the potential alkali–silica reaction of different types of aggregate in the mortar with and without fly ash. Four types of aggregate used in this study include limestone, andesite, rhyolite, and sandstone. Fly ash was used as a cement replacing material. The chemical compositions of materials were analyzed. The potential risk of aggregate was evaluated through the expansion of the mortar bar in the sodium solution at 80 °C for 14 days. It was found that rich silica aggregates including andesite, rhyolite, and sandstone show potential reactivity when compared to limestone with low silica content. However, the chemical composition of aggregate was not mainly affected on the potential reactivity. Fly ash significantly inhibited the expansion of mortar bars containing any aggregate types.