Alkali-Silica Reaction in Portland Cement Concrete: Testing Methods and Mitigation Alternatives

Identifying the susceptibility of an aggregate to alkali-silica reaction (ASR) before using it in concrete is one of the most efficient practices for preventing damage and failure. Several tests have been developed for identifying aggregates subject to ASR, but each has its limitations. A three-year research study was initiated on January 1, 1998 at the University of Texas at Austin for investigating ASR in portland cement concrete. The scope of the study was essentially three fold: (1) investigate the predictive ability of ASTM C 1260 and C 1293, (2) develop more accurate and more efficient modifications of these procedures, and (3) investigate ASR mitigation alternatives. Aggregate samples from 14 sources from around the United States were acquired for the investigation. Aggregates were used in an extensive testing program during which guidelines for predicting the potential ASR of aggregates were developed and recommendations for minimizing concrete damage due to ASR were formulated. This report includes a review of the state-of-the-art of ASR, an evaluation of testing protocols and recommendations for dramatically shortening test time, test results, and mitigation options.