|
Description: This guide specification provides the specifier with a variety of methods to control ASR, including tests to determine if aggregates are potentially reactive and methods to demonstrate how pozzolans and blended cements can effectively control ASR.
Most aggregates are chemically stable in hydraulic cement concrete, without deleterious interaction with other concrete ingredients. However, this is not the case for aggregates containing certain siliceous minerals in concrete, resulting in detrimental expansion and cracking of concrete structures. Alkali-silica reactivity (ASR) has been reported worldwide since 1940. Fortunately most concrete is not affected by this condition. Although the risk of catastrophic failure and the number of affected structures are low, ASR-induced cracking can exacerbate other deterioration mechanisms such as occur in frost, deicer, or sulfate exposures. ASR can be controlled by the methods presented in this guide specification. This guide specification provides several options, including the use of mineral admixtures, for the user to control ASR.
|