Review, sampling, and evaluation of landfilled fly ash

The growing scarcity of high-quality fly ash has urged concrete researchers and practitioners to investigate unconventional sources such as landfilled fly ash. This paper presents a summary of the potential issues with using landfilled fly ash as a concrete pozzolan. To that end, successful characterization of fly ash landfills is crucial to determine the viability of a given landfill as a pozzolan resource. Accordingly, a statistical sampling approach was developed and applied to a Class F fly ash landfill in Pennsylvania. Samples taken from the landfill were tested based on ASTM C618 requirements and statistical analyses were performed to determine the necessary beneficiation strategy. Blended mortar and concrete mixtures incorporating the beneficiated fly ash were tested for slump, plastic and hardened air content, compressive strength, and mitigation of alkali-silica reaction (ASR).