Experimental study of the effects of mechanical restraints on ASR expansions in concrete

Abstract

This paper summarizes an experimental campaign devoted to the study of the effect of (internal and external) mechanical restraints on Alkali-Silica Reaction (ASR) expansions in concrete made with sodalime (SL) glass as reactive aggregate. The campaign included the development of two new experimental setups. The first setup made it possible to measure ASR expansion curves at the level of a single interface between a reactive aggregate and a cementitious matrix. For this purpose, small sandwich-like specimens, with cement paste or mortar on top and bottom of a disc of SL glass in the middle, were used. For the second experimental setup, a true-triaxial machine was used to obtain ASR expansion curves of concrete cubical specimens subjected to three different triaxial stress states. Based on the results obtained, a reaction-expansion mechanism is proposed that might explain the effects of the stress state on the ASR expansions of concrete.