Abstract
Even though alkali silica reaction (ASR) is one of the main deterioration mechanisms in Norway, only a few Norwegian concrete structures with ASR have so far been rehabilitated. As a basis for planning and executing repair works, detailed condition surveys including laboratory analyses are required in order to diagnose the cause of damage, to evaluate the extent of damage over the structure and as a basis for calculating the remaining load capacity. This paper presents the experiences from an extensive condition survey and FEM-analyses of two about 40 years old Norwegian concrete dams with ASR, one slab concrete dam and one arch dam. The background for the project was that the slab in the mid corner of the slab dam suddenly lifted from the supporting pillar due to expansion. In 2006 this slab concrete dam was rehabilitated, and in 2008 a monitoring program is planned to be established.