DEVELOPMENT OF ENHANCED TEST METHODS TO EVALUATE ALKALI-SILICA REACTION IN CONCRETE

摘要

The research presented in this paper studies the effect of sample geometry and temperature on expansion due to alkali-silica reaction (ASR) in concrete. Expansions of cubes and cylinders are compared to those of the standard prisms. Control samples, samples with fly ash (FA) and others with slag are investigated at two temperatures, 38°C and 60°C. At 38°C, results showed that smaller samples have higher expansion at early ages. However, larger samples such as cubes and cylinders seem to reach higher expansion compared to prisms after 32 weeks for both control and samples with fly ash. In addition, the results showed that higher temperature accelerated the expansion of the different sample geometry. However, in the case of the samples with no supplementary cementing materials (SCM), the ultimate expansions at 60°C are not higher than that of the samples tested at 38°C. Secondly, the degree of hydration and pozzolanic reaction of different SCM were studied using thermal analysis to predict their alkali binding capacity at different temperatures. The results provide a better understanding of the evolution of their hydration products. The hydration of SCM was higher at temperature higher than 23 °C, especially at ages earlier than 28 days.