Alkali-silica reactions and silica fume - 20 years of experience in Iceland

In Iceland, silica fume has been blended with all Icelandic cement since 19 79. Icelandic cement is unique in many ways. Common raw material for cement production is not found; therefore, less appropriate material is utilised for production. As a result, the alkali content of the cement clinker is re latively high. Because alkali-silica reactive aggregates are relatively com mon and favourable environmental conditions for alkali-silica reaction (ASR ) prevail, ASR became a serious problem in Iceland during the 1970s. At tha t time research began in Iceland to look for pozzolanic material to counter act ASR reactions in Icelandic concrete. Since the opening of a ferrosilici um plant in Iceland in 1979, silica fume has been utilised as pozzolanic ma terial in all concrete. After 20 years of service there are no signs of ASR in this concrete in Iceland. These findings are supported by scientific re search, standardised alkali-silica test methods, and field observations. (C ) 1999 Elsevier Science Ltd. All rights reserved.