Computational modeling of expansion and deterioration due to alkali–silica reaction: Effects of size range, size distribution, and content of reactive aggregate

This paper examines the effects of size range, distribution and content of reactive aggregate on concrete expansion and deterioration due to Alkali–Silica Reaction (ASR). The ASR model was formulated within the Multiphysics framework of the Lattice Discrete Particle Model to account for the heterogeneous character of ASR expansion, cracking and damage. The adopted model was extended in this study to include a general piecewise linear sieve curve that allows selecting the coarse aggregate pieces to be reactive or non-reactive according to content and size range of actual reactive aggregate. The overall framework was calibrated and validated by comparing simulation results with three sets of experimental data from the literature. The results demonstrate that the model can capture all the main features of the experimental evidence. In particular, the so-called “pessimum size” of ASR expansion is captured and explained as the competition results between porosity and diffusion effects in the ASR model. Based on simulation results, it is shown that ASR-induced cracks are mainly generated by the presence of reactive aggregates of different sizes producing heterogeneous expansion at the mesoscale. The loss in mechanical properties is found to be strongly related to these cracks and the heterogeneous expansion as opposed to the measured macroscopic strain.