High Volume Ash Concrete

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High Volume Ash Concrete

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High Volume Ash

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

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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

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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 concretes environmental impact

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Product Comparisons

• 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

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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
  concretes durability. Materials that last longer
  reduce the demand for natural resources and
  reduce the associated environmental impacts of
  extracting and processing them.

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Cost Considerations

• High volume fly ash usually costs the same as
  conventional

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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

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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

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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.

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Works Cited

• The Green Resource Center, Berkley, CA
  www.greenresourcecenter.org