Influence of Mineral Fillers (MF) on ASR-Induced Expansion and Deterioration

Alkali-silica reaction (ASR) is a harmful mechanism that can damage concrete infrastructure. Various approaches, including accelerated test procedures, have been developed to assess potential aggregate reactivity in the laboratory. If, on the one hand, these methods are quite established for assessing the reactivity of fine and coarse aggregates, it is still very unclear how to appraise the reactivity and impact of using mineral fillers (MF) in the laboratory. This project aims to understand the effect of MF on ASR-induced expansion and deterioration. Concrete specimens containing reactive and non-reactive coarse and fine aggregates were fabricated with four fillers (derived from ASR-reactive and non-reactive) at a replacement level of 15% using two distinct design approaches (i.e., replacement of PC or fine aggregates). These specimens were stored in conditions enabling ASR-induced development over 360 days, and their expansion over time was monitored throughout. At 360 days of exposure, physical (i.e. porosity), mechanical (stiffness damage test, modulus of elasticity and compressive strength) and microscopic (damage rating index) were conducted. Results indicate that mixtures incorporating MF and replacing PC display changed expansion and damage over time; while granite positively impacted AAR development, the greywacke fillers displayed similar behaviour to control mixtures. On the other hand, limestone and dolomite fillers worsened the expansion and deterioration process.