The International Conference on Alkali-Aggregate Reaction (ICAAR) in Concrete is held every 4 years, bringing together researchers, engineers, scientists, the industry and students from all over the world since 1974. AAR was discovered in the mid 1930’s by Thomas Stanton of the California Division of Highways and remains one of the leading causes of early deterioration in concrete. Topics such as: understanding the reaction mechanisms and the affecting factors; testing methods and preventative measures; diagnosis, evaluation and prognosis; monitoring and NDT; structural effects and modeling at all scales; and repair and remedial measures are presented and discussed. These topics have been extended to other types of deterioration such as delayed ettringite formation (DEF). Cases of deterioration and management are also shared to strengthen the ICAAR community and the community the participants serve. In light of the current climate change crisis, sustainable approaches to new structures will be introduced so that we can help tackle this global issue together.