Do the geometry and aggregates size influence external sulfate attack mechanism?

ESA performance testing protocols are mainly a set of exposure conditions, monitoring strategy, and specimens configuration. Although the large feedback on the representativeness of exposure conditions and the relevance of monitored parameters, the effect of specimen configuration still deserved to be studied. In order to investigate the effect of composition and geometry on ESA degradation progress and performance evaluation, an experimental campaign was conducted in this study. Among the 8 tested specimen configurations, 5 geometries (prismatic, cylindrical and 3 hollow cylindrical geometries) and 3 compositions (concrete, concrete equivalent mortar and standard mortar), the cylindrical mortar specimen was selected as the most adapted configuration, in term of ESA degradation expression, for the adopted performance testing procedure. The different configurations lead to the same overall mechanism of degradation but the geometry and the composition influenced the magnitude of some chemical or physical degradation parameters, due to couplings between chemical and mechanical degradation.