ISEC 08


CAN THE ACCELERATED PRISM TEST EVALUATE ALKALI-SILICA REACTIVITY?

MOHAMMAD S. ISLAM, SYED F. AHMAD


Abstract

The purpose of this study was to evaluate the alkali-silica reactivity of twelve aggregates based on the ASR-induced expansions of ASTM C 1260 and modified ASTM C 1293. The mortar bars and concrete specimens were prepared and fully submerged in the 1.0N NaOH at the temperature of 80°C. The ASR-induced expansions of the test specimens were recorded at various immersion ages. The expansion limits of alkali-cured prisms were proposed at the test durations of 4 and 8 weeks. Finally, the trial aggregates were classified based on the aggregate mineralogy and the expansion limits of mortar bars at 14 and 28 days, and they were compared with the proposed expansion limit of concrete prisms at the ages of 4 and 8 weeks. It was acknowledged that the 4-week failure limit of concrete prisms under the 1.0N resulted in some innocuous aggregates to be rated as reactive. However, the ASR-classifications of the trial aggregates showed a perfect correlation based on the results obtained from the extended failure limits of mortar bars and concrete prisms, and those from the mineralogy of aggregates.

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