This report describes research conducted at BRE into the structural performance of concrete suffering from alkali-silica reaction. The first part covers tests on concrete specimens and prestressed beams undergoing alkali-silica reaction whilst on the exposure site at BRE. The results indicate that research into alkali-silica reaction using accelerated conditioning can be reliably assumed to be directly applicable to real structures.The second part covers freeze-thaw tests on further concrete specimens with alkali-silica reaction from the exposure site. Results show that the durability of concrete with alkali-silica reaction may be further affected by the secondary effect of freeze-thaw attack. 41 pages.