ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS VICKSBURG United States
This study focused on development and evaluation of a novel autoclaving procedure for the rapid evaluation of concrete aggregates for alkali-silica reaction susceptibility. The use of high pressure and temperature autoclaving methods was selected to speed evaluation timeframes from months to a few days. A total of 30 aggregates of varying mineralogy and reactivity were evaluated as part of the study that was divided into two phases. The first phase of research focused on development and optimization of the autoclaving procedures, including temperature, alkali loading, and test duration. Results from Phase 1 were used to identify optimal testing parameters that were then used during a Phase 2 round robin testing study, which included internal laboratory testing as well as four external laboratories. Strong correlation was observed between autoclave expansion results and the results of ASTM C1260 and C1293 standard test methods. In addition, within- and multi-laboratory variability were with-in acceptable bounds provided by ASTM standards. Overall, the research indicated that autoclaving is a viable option for rapid evaluation of aggregates using testing procedures that can be completed in approximately three days.