High Volume Ash Concrete

High Volume Ash The purpose of this presentation is to make known an alternative resource in conventional concrete mixtures

Conventional Concrete Extremely versatile Good strength when reinforced with steel Can be cast to nearly any desired shape The manufacturing of Portland cement accounts for 6 to7% of the CO2 that humans produce

What is Fly Ash? A by-product of coal-fired power plants It uses up space in landfills When used in concrete, it displaces more than 25% of the cement Creates a more stronger bond Reduces concrete’s environmental impact

Product Comparisons Conventional Concrete High Volume Fly Ash Concrete Less energy intensive manufacture Higher ultimate strength More durable Uses a waste by-product Less global warming gases created Is a LEED certified material Conventional Concrete Energy intensive manufacturing Weaker ultimate strength Less durable Uses virgin material More global warming gases created

Environmental Considerations There is no difference in energy performance (as an insulator) in fly ash compared to conventional The fly ash is less permeable to water, protecting reinforcing steel and adding to the concrete’s durability. Materials that last longer reduce the demand for natural resources and reduce the associated environmental impacts of extracting and processing them.

Cost Considerations High volume fly ash usually costs the same as conventional

Installation Improves the workability of concrete because it aids in the placement of concrete into formwork and around reinforcing steel. Consequently, less water is needed in the mix. Sets more slowly than conventional Concrete

Health Attributes There are traces of heavy metals in the fly ash. Some debate that the metals are effectively locked into the cement matrix, preventing their release. By using fly ash in concrete rather than “landfilling” it, the potential for the metals to leach into the environment is reduced. Concerns have also been raised about the higher incidence of Radium-226 in fly ash

Alternative Resources Rice hull ash, created by the controlled burning of an agricultural waste product, can be added to mixes to further increase the strength and reduce the permeability of fly ash concrete.

Works Cited The Green Resource Center, Berkley, CA www.greenresourcecenter.org