Experimental and modelling validated ASR mitigation concept linking cement composition and aggregate reactivity

This study validates a chemistry-based framework for mitigating alkali–silica reaction (ASR) through binder design. Eleven binders spanning a controlled CaO–SiO 2 –Al 2 O 3 compositional range were combined with six reactive aggregates and assessed using three accelerated expansion protocols. Expansion was evaluated together with pore solution analysis, Damage Rating Index, thermogravimetric analysis, SEM–EDX, and thermodynamic modelling. Lower CaO and higher SiO 2 and/or Al 2 O 3 were associated with reduced expansion and cracking. Modelling reproduced the main reaction product assemblages identified by microscopy, distinguishing Ca-rich C-S-H-like products from low-Ca shlykovite-type products. Solubility simulations constrained by measured pore solutions indicate that silica dissolution increases with alkali availability and Ca-bearing buffering, but remains limited in low-Ca, SCM-rich systems. The combined dataset links binder chemistry, pore solution composition, and aggregate-internal precipitation conditions to ASR damage.