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Location
Lexington, Kentucky
Start Date
6-5-2026 8:00 AM
End Date
6-5-2026 8:30 AM
Description
Concrete producers are under pressure to reduce the carbon footprint of concrete while maintaining a reliable supply of supplementary cementitious materials. Meanwhile, U.S. coal production in 2023 declined to less than half of its 2008 peak, significantly reducing the availability of fresh ASTM C618 compliant fly ash. At the same time Ohio contains more than 145 million cubic yards of coal combustion residuals stored in ponds, representing a large and underutilized source of potential fly ash for concrete applications. This study evaluates the suitability of harvested Ohio ponded fly ash for use in concrete through practical and specification-driven testing aligned with current industry standards. Fly ash samples are collected from locations throughout an Ohio pond and characterized by the depth. Overall site variability is assessed prior to recombining samples into composite samples. The composites are then evaluated using ASTM C618 test methods and assessments of reactivity, hydration characteristics, and setting times. Additional mortar cubes with 50% cement replacement are produced to assess the effects of high replacement rate on concrete properties. Several measures, including sieving and milling of samples are applied to low reactivity samples to improve performance. In this presentation, attendees learn how site variability, compositing strategies, and simple post-harvesting processing methods influence the ability of ponded fly ash to meet ASTM C618 requirements and perform reliably in concrete mixtures. Despite the variability within the pond, results indicate appropriately composited ponded fly ashes can, in most cases, meet ASTM C618 specification requirements, and the use of simple post-harvesting treatment procedures rapidly improve performance of other ashes.
Document Type
Presentation
Archival?
Archival
Included in
Energy Systems Commons, Environmental Indicators and Impact Assessment Commons, Environmental Monitoring Commons, Mining Engineering Commons, Oil, Gas, and Energy Commons, Structural Materials Commons, Sustainability Commons
Evaluating the Properties of Ohio Ponded Fly Ash for Reliable Use in Concrete Mixtures
Lexington, Kentucky
Concrete producers are under pressure to reduce the carbon footprint of concrete while maintaining a reliable supply of supplementary cementitious materials. Meanwhile, U.S. coal production in 2023 declined to less than half of its 2008 peak, significantly reducing the availability of fresh ASTM C618 compliant fly ash. At the same time Ohio contains more than 145 million cubic yards of coal combustion residuals stored in ponds, representing a large and underutilized source of potential fly ash for concrete applications. This study evaluates the suitability of harvested Ohio ponded fly ash for use in concrete through practical and specification-driven testing aligned with current industry standards. Fly ash samples are collected from locations throughout an Ohio pond and characterized by the depth. Overall site variability is assessed prior to recombining samples into composite samples. The composites are then evaluated using ASTM C618 test methods and assessments of reactivity, hydration characteristics, and setting times. Additional mortar cubes with 50% cement replacement are produced to assess the effects of high replacement rate on concrete properties. Several measures, including sieving and milling of samples are applied to low reactivity samples to improve performance. In this presentation, attendees learn how site variability, compositing strategies, and simple post-harvesting processing methods influence the ability of ponded fly ash to meet ASTM C618 requirements and perform reliably in concrete mixtures. Despite the variability within the pond, results indicate appropriately composited ponded fly ashes can, in most cases, meet ASTM C618 specification requirements, and the use of simple post-harvesting treatment procedures rapidly improve performance of other ashes.
