Findings from the University of Texas at Austin ASR Exposure Site after 20 Years

This paper presents the findings on the University of Texas at Austin outdoor exposure site after 20 years. The site was created in 2001 and is considered to be a warm weather site when compared to other outdoor exposure sites. The site contains exposure blocks subject to ASR and DEF. After 20 years, the exposure site contains more than 1000 exposure blocks and the data that has been collected has been used to update ASR standards, specifications, and guidance documents. This site contains materials from around the world including over 40 aggregates and at least 50 types of prevention measures. Findings from over the years have helped develop correlations between laboratory test methods and the field exposure blocks including a major concern that test methods such as the accelerated mortar bar test and the concrete prism test are not able to determine the replacement amounts of SCMs to prevent ASR in high alkali loading field exposure blocks. In addition, the site has shown that lithium nitrate does not prevent ASR in field blocks with high alkali loadings.