| Fundamental features of alkali-silica reaction (ASR) in concrete with glass as aggregate were studied experimentally, using the ASTM C-1260 test method and microanalytical techniques such as SEM and EDXA. Important variables which contribute to the ASR expansion of concrete containing glass aggregate were investigated. A pronounced particle size effect was identified for different types of glass in the accelerated test, which is difficult to explain by the conventional hypothesis based on reaction chemistry alone. A chemo-physico-mechanical approach was thus introduced to take into account also transport and mechanical processes. Experimental results indicated that the pessimum size depends on both the glass aggregate reactivity and gel permeability of the cement matrix, confirming the hypothesis that the gel formation and gel permeation are the chemical and physical processes that control the pessimum size. A micromechanical ASR model was developed which allows the prediction of ASR expansion of concrete, given material parameters and properties of individual phases. Analytical results from numerical simulation showed general agreement with experimental observations. |
