Re-evaluation of standard mortar bar and concrete prism tests for alkali-aggregate reactivity

摘要

The effectiveness of the mortar bar ASTM C227 and concrete prism CSA A23.2-14A tests for evaluating the potential alkali-aggregate reactivity of classical alkali-silica, late expansive siliceous and alkali-carbonate aggregates is discussed. It is emphasized that petrographic examination is an essential preliminary step in the evaluation of potential alkali reactivity of all aggregates. The expansion limits set to differentiate between deleteriously expansive and innocuous cement-aggregate combinations by ASTM, CSA, U.S. Corps of Engineers, U.S. Bureau of Reclamation and by the author are evaluated for use with classical alkali-silica, late-expanding siliceous and alkali- carbonate reactive aggregates.