Numerical and experimental study of ASR in concrete at the meso-level

Abstract

In this paper, an ongoing research project on the mechanisms of concrete deterioration due to Alkali-Silica Reaction (ASR) is presented, together with some preliminary results. The research program includes both experimental and numerical modelling work. The first part includes the development of two new experimental setups, one devoted to study the ASR expansion mechanisms at the level of a single matrix-aggregate interface and the other to the study of ASR expansions of cubic concrete specimens under triaxial confinement. The second part includes the formulation and numerical implementation of a chemo-mechanical model for ASR expansions in concrete at the meso-level. The model considers three main diffusion/reaction field equations for the concentrations of silicates, calcium and alkalis in concrete pore solution, complemented by a number of chemical kinetics and chemical equilibrium equations. The volume fraction distribution of the solid constituents of the hardened cement paste and the reaction products evolve with the progress of the reaction, determining the diffusivity properties of the material and, eventually, inducing expansions.