Slot cutting an AAR-affected dam: case study of the Salanfe dam

Salanfe dam was built in 1952. Since the early 1970s, monitoring of the behaviour of the dam based on pendulums started to show an irreversible deformation upstream, in particular at the most pronounced kink between the left wing and the central part. After detailed studies spanning several years, investigations proved that the dam was affected by alkali-aggregate reaction (AAR) inducing swelling of the concrete mass. Since 1993, the total irreversible downstream-upstream displacement has reached approximately 60 mm. Several networks of cracks have also appeared in the main kink area. To ensure the structural safety of the dam by reducing the effects of AAR, and to release the consecutive compressive stress state, it was decided to perform slot cutting on the dam.