Alkali-silica reaction in concrete containing glass

The use of surplus waste glass in concrete has been avoided on the grounds that it is known to undergo harmful alkali-silica reaction (ASR). As part of a research project to develop draft specifications for glass in concrete, a major ASR testing programme was undertaken to establish appropriate use of glass in concrete which avoided harmful ASR. The British Standard for assessing ASR reactivity of aggregate—BS 812-123—was used. Testing was conducted on concrete mixes containing glass as either fine aggregate, filler aggregate, or as a Type II addition. Glass used as fine aggregate was found to produce significant expansion for both green and amber glass. GGBS and metakaolin had the effect of reducing this expansion considerably. Concrete containing powdered glass displayed much less expansion. A simple schematic model for the alkali-silica reaction of glass, based on glass dissolution mechanisms is proposed, and related to the test results.