ESTIMATING FLY ASH QUALITY TO MITIGATE ALKALI SILICA REACTION BY API-METHOD

Abstract

The API-method was proposed for assessing rapidly the pozzolanic reactivity of fly ash in the last study. However, there was either high positive correlation between the API-value and mitigating ASR effectiveness of fly ash, i.e. the higher API, the higher mitigation effectiveness. The API was estimated as a generic index including the effects of chemical and physical properties of fly ash. In case of using Pyrex glass aggregate, the main chemical components of ASR gel produced on the aggregate were almost the same without relating to the fly ash usage, i.e. Na₂O/SiO₂ and K₂O/SiO₂, thus the ASR mitigation was estimated to be derived from inhibition of producing ASR gel.