Alkali-aggregate reaction (AAR) can cause serious cracking and deterioration of concrete structures, particularly those in moist environments. This requires the presence of sufficient amounts of reactive components, alkali and moisture. Damage from AAR has been identified in many locations in structures in a variety of environments, including marine condition, which is more aggressive than normal exposure. The reactivity of various aggregates in concrete mixes of low to high alkali content, was tested under exposure conditions of 100 per cent humidity at 38, 60 and 80 degrees Celsius, as well as under conditions of storage in seawater at the same temperatures. Expansion of specimens was monitored for two years. Results indicate that the type of aggregate and the alkali content of concrete have the greatest effect on AAR expansion. The 60 degrees Celsius exposure condition was very efficient in causing expansion of aggregates susceptible to AAR. However, the exposure to salt solution (seawater) did not have a significant effect on AAR expansion during the two years of exposure, and this situation is not expected to change. (a) For the covering entry of this conference, please see ITRD abstract no. E217099.
Samenvatting