Crystallization pressure in ASR expansion quantified by thermodynamic modeling and micromechanics

Establishing direct relations between alkali-silica reaction (ASR) expansion, crystallization pressure build-up, and phase assemblage changes is a critical step towards predictive modeling of ASR damage. To address this, we propose a strategy that combines thermodynamic modeling with micromechanics. First, we complete the thermodynamic database for ASR products, including nanocrystalline ASR-P1 data and improving the previous data for crystalline products. Phase assemblage is determined by accounting for cement hydration and amorphous silica dissolution kinetics. Crystallization pressure estimates are provided based on pore solution supersaturation with respect to ASR products. These phase assemblage and crystallization pressure estimates are then used as input for analytical micromechanical estimates of elastic properties degradation and macroscopic expansion. The model strategy that integrates damage considerations and the gel-like nature of ASR-P1 provides a better comparison with experimental results.