Condition assessment of alkali-silica reaction affected concrete under various confinement conditions incorporating fine and coarse reactive aggregates

The multi-level assessment, combining microscopic (i.e., Damage Rating Index) and mechanical (i.e., Stiffness Damage Test) techniques, has been effectively used to appraise the deterioration cause by alkali-silica reaction (ASR) in unconfined concrete. However, the impact of restrainment on ASR-induced deterioration originated from reactive fine and coarse aggregates has not been fully explored. This study intends to evaluate the effect of the confinement degree and reactive aggregate type on ASR damage development through the multi-level assessment. Twenty-four concrete blocks incorporating two different reactive aggregate types (fine and coarse) and three confinement configurations (unconfined, 1D, and 2D) were produced and monitored over time. Upon reaching the desired expansion levels (0.08% and 0.15%), cores were retrieved from three main directions (vertical, longitudinal and transverse) and the multi-level assessment was performed. Results indicate that ASR-induced expansion and damage are influenced by the reactive aggregate type, confinement configuration and coring direction.