Abstract
This study aims at revealing the mechanisms of the influence of NaCl externally supplied on the expansion of mortars due to the alkali-silica reaction. In a reactive aggregate-bearing mortars with relatively low alkali contents, the promotion of their expansions in 1N NaCl solution at 38°C was caused by a rise of OH- ion concentration in the pore solution. The increase in OH- ion concentration in the pore solution in mortars was responsible for the intrusion of NaCl into mortars containing a reactive aggregate. In a reactive aggregate-bearing mortars with a relatively large amount of added NaOH, a high possibility that a part of the unusual expansions of mortars was caused by the formation of ettringite during the immersion in NaCl solution.
