Influence of the expansive sites distribution on alkali-silica reaction expansion under applied stress: Crack orientation as a key factor for expansion transfer

Abstract

The influence of the expansive site distribution of the alkali-silica reaction (ASR) on the expansion behavior under applied stresses was numerically investigated to verify the mechanical factor of expansion transfer. In the analysis, the aggregate and mortar phases were individually modelled by mesoscale discrete analysis. To reproduce expansive site distribution and time-dependent behavior, expansive phase model, pressure development model, and creep model were developed. As a result, expansion transfer was observed for the model based on the reaction rim assumption and the crack effect model under applied stress of less than 10 MPa. A detailed numerical investigation identified that the cracks under applied stress in the reaction rim model are modified more easily than those in the gel pocket model, despite crack generation being inhibited. Consequently, expansion transfer was found to be significantly influenced by the crack orientation because of the mechanical interactions at the expansive sites under applied stress.