The global saga of alkali aggregate reactions. Endeavour–achievements–International AAR-conferences (ICAAR) and RILEM technical committees

This paper presents a historical overview of the endeavours of international engineers and scientists to understand, control and prevent damage from alkali aggregate reactions (AAR) in concrete. It is now 85 years since AAR first were reported as a deleterious deterioration mechanism in concrete, and it is 50 years since the first International Conference on AAR (ICAAR) was organised in Denmark in 1974. In 1988, the first Technical Committee (TC) on AAR in concrete was established by RILEM ( The International Union of Laboratories and Experts in Construction Materials, Systems and Structures). Part of RILEM performance-based testing concept is planned, adopted, and implemented as new European standards and guidelines. Eventually, this paper presents a summary of where we are today in AAR research, identifies key milestones and addresses some specific topics for future research.