Fly Ash is Green Not Gray


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Just a brief overview of Fly Ash: used as benefit to both concrete performance and sustainability.

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Fly Ash is Green Not Gray

  1. 1. Fly Ash is Green, Not Gray By: Nicholas Edwards Ready Mix USA USGBC – East Tennessee Meeting February 19, 2010
  2. 2. Overview Fly Ash Basics & Overview What are Pozzolans? Fly Ash Production – Process Fly Ash Properties Plastic Concrete Hardened Concrete Sustainable Development
  3. 3. Fly Ash Basics What: Non Combustible By Product of Coal Power Production Physically: < 100 Microns Spherically Shaped Particles, “Flies” Industry Term: CCP – Coal Combustion Product Derived: Coal Furnaces, Plants Collected: As Coal is Burned for Power Production Usages: Construction Materials, Pozzolanic Properties
  4. 4. Production Process Particles Rise In Flue Gas Collected By Highly Efficient Process Electro-Static Precipitators Testing Determines Usage Opportunity Highly Regulated Process
  5. 5. Logistics & Handling Materials are Randomly Tested at Plants Pneumatically Loaded Into Dry Bulk Tankers “Fly” Ash Fugitive Emissions – Dust Suppressors Tankers Unload via Air Blower Into Silos FA – Stored in Silos Until Concrete it Produced
  6. 6. Classifications of Fly Ash Type F Most Common for Concrete From Anthracite Coal – Old Coal Needs Activator (CaOH) Requires Cement Agent & H2O Locally Available (LEED help) Type C Widely Used for Concrete From Lignite Coal – Young Coal Does Not Require Activator Self Cementing Properties
  7. 7. Classifications of Fly Ash Specifications for Definition & Testing of Fly Ash ASTM C 618 Fly Ash for use as Mineral Admixture in Concrete ASTM C-311 Sampling and testing fly ash... C- Specifications for Fly Ash Use in Ready Mixed Concrete ACI 211 Standard practice for Normal, Heavyweight, & Mass ACI 212 Admixtures for Concrete ACI 301 Specification for structural concrete for buildings ACI 318 Building code requirements for reinforced concrete ACI 350 Concrete sanitary engineering structures
  8. 8. Pozzolanic Properties The Original Volcanic Ash (Pozzolana) Original: Romans Original Ash Concrete Technologists Origin: Origin Pozzuoli, Italy
  9. 9. Fly Ash & Concrete Partial Replacement of Cement (Up To 30% Normally) HVFA – Sustainable Movement Value Added Mix Products Like Flowable Fill Benefits Plastic & Unhardened Concrete Value: Value Improves Concrete Chemistry – Creates CSH
  10. 10. Fly Ash & Plastic Concrete Reduces Water Demand Spherical Shape Reduces Dependence on Water Increases Workability Ball Bearing Effect Increases Ability to Pump & Finish Reduces Bleeding Fines Reduce Size and Frequency of Water Capillaries Reduces Segregation Fines Hold a Mix Together Reduces Heat of Hydration Slows Set, Reduces Thermal Cracking Propensity
  11. 11. Fly Ash & Hardened Concrete Reduces Permeability & Increases Water tightness Finer Particles Solidify Cement Matrix Reduces Drying Shrinkage Lowered H20 Demand & Reduction of Cement Reduces Alkali-Silica Reactivity Alkalis are Not Free to React w/Silica Aggregates Reduces Sulfate & Acid Attack CaOH is Not Available for Attack Greater Overall Strength & Durability Slower, Higher Strength Curve
  12. 12. Role In Sustainability Related LEED Credits M.R. 4.1 – Recycled Materials – Pre Consumer M.R. 4.2 – Recycled Materials – 20% M.R. 5.1 – Regional Materials M.R. 5.2 – Regional Materials – 20% I.D. 1.1 – 1.4 – Innovation Design Fly Ash in Pervious Concrete Concrete Can Help Earn 25 LEED Total Points Key Is Working With Entire Project Team Early
  13. 13. Role In Sustainability
  14. 14. Environmental Benefits 2008 – 71.1 Million Tons of Fly Ash Produced 2008 – 29.1 Million Tons Recycled (42%) What About the Other 42 Million Tons ? LANDFILLS, SLUICE PONDS, & CONTAINMENT Recycling This Would Have Saved 27,500 Acre Ft Landfill (American Coal Ash Association) EPA Targets 50% Recycling Rate by 2011
  15. 15. Environmental Benefits Recycling of Fly Ash Reduces Consumption of: Virgin Materials Quarried Portland Cement (Sustainable Tradeoff) About 1 Ton of CO2 is Created Per Ton of Cement For Each Ton of Fly Ash Recycled in Concrete, 1 Ton of CO2 Reduced
  16. 16. Environmental Benefits
  17. 17. Precautions & Hazardous Threat U.S. Geological Survey (1997) – Radioactive Element Content In Line With That of Common Soils Should Not Be a Source of Alarm
  18. 18. Ready Mix USA & Fly Ash 2009 – 3000+ Tons Recycled (Locally) Product Value Cost Savings CO2 Reduction When Do We Not Use Fly Ash ? High Early Strengths Specifiers Requirements/Project Specifications Certain Architectural Elements
  19. 19. Final Thoughts & Questions Thanks For Listening. Email: