Nanomechanics of ASR Gels from Coarse-Grained Simulations

Abstract

Despite alkali–silica reaction (ASR) being a major durability problem in concrete, structural features and properties of ASR gels remain poorly understood. Inspired by the success of coarse-grained (CG) simulations in unveiling key features of calcium-silicate-hydrate (C-S-H) gels, we deploy these simulations to model ASR gels. Our goals are (1) to test the suitability of these simulations to capture ASR gels structural features and mechanical properties; and (2) to quantify any alkali-dependency in the response. Effective interactions obtained at the molecular scale for Na-ASR and K-ASR (sodium-ASR and potassium-ASR) products are adopted. Simulation results are consistent with the available data on the structure, elastic, and viscous behavior of ASR gels. The ASR gel mesotexture development and mechanical properties are ion-specific, with Na-ASR showing a more rigid/less viscous behavior overall. Our results demonstrate the suitability of CG simulations to investigate ASR.