The adverse effects from reactions of reactive aggregates in concrete dams are well known worldwide. The mechanisms ruling alkali silica reactions (ASR) are partly but not fully understood. A majority of the Swedish concrete dams are so far considered to be protected from ASR due to the common use during the 50:s, 60:s and 70:s of the Swedish low alkali cement Limhamn LH. Today there is a discussion if it still is possible to develop ASR after very long time in dams with reactive aggregates and use of low alkali cement. Via selection of seven facilities in the Swedish alpine area, where reactive aggregates are common, the current paper is aiming to compile experiences from almost 50 years of exposure. In the paper two examples on ASR in spite of use of low alkali cement are shown.