An Innovative Approach to Fly Ash Characterization and Evaluation to Prevent Alkali-Silica Reaction

The main objective of this study was to conduct a full-scale characterization of different types of fly ashes using conventional as well as advanced techniques and evaluating their effectiveness to prevent alkali-silica reaction (ASR) using an emerging accelerated concrete cylinder test (ACCT). The full-scale characterization of fly ashes involves evaluation of type and content of crystalline phases and amorphous content by quantitative X-ray diffraction (OXRD), soluble available alkalis (ASTM C311), and pore solution chemistry along with determination of parameters by the conventional ASTM 0618. A favorable comparison between characteristic chemical and mineralogical parameters of the fly ashes and ACCT-based ASR performance prediction was observed. This combined innovative approach was found to be effective to test the effectiveness (optimization) of different types of fly ashes to prevent ASR in a rapid (within 75 days) and reliable manner and formulate case-specific, performance-based, ASR-resistant concrete mixtures using locally available fly ashes.