Briefing: Delayed ettringite formation in concrete structures Available to Purchase

Delayed ettringite formation (DEF) is a relatively rare but potentially severe form of internal sulphate attack of concrete. In the worst cases it has caused loss of serviceability of the affected concrete structure. DEF was first identified as a problem in heat-cured concrete during the 1980s and in recent years has also been found to occur in in situ concrete structures. Once established, it can cause expansion and cracking, which weaken concrete members and accelerate deterioration by other mechanisms such as reinforcement corrosion. This briefing explains how DEF occurs and how it is diagnosed and discusses how it can be prevented and managed in concrete structures.