Laboratory short-term evaluation of ASR - A contribution

Accelerated tests were performed at 80 degreesC to evaluate alkali-silica reactions (ASRs) in mortars made with alkali-enriched cement. Sodium salts (NaCl, Na2SO4, and NaHCO3) and sodium hydroxide were used in the mortars, and the microstructural alterations induced in the mortars by the alkaline compounds were investigated as their effect on mechanical properties. Data so far collected indicate that, at this temperature, the expansion of mortars without reactive aggregate is limited and, at least at the investigated alkali concentration, negligible compared to the expansion of mortars containing artificial reactive aggregates. Results show, however, that the extent of expansion can be influenced by the type of salt used to increase the alkali concentration. (C) 2001 Elsevier Science Ltd. All rights reserved.