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Sustainability, Materials Engineering and Concrete

Sustainability, Materials Engineering and Concrete. Cabrillo College ENGR45. Sustainability & Materials Engineering.

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Sustainability, Materials Engineering and Concrete

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  1. Sustainability, Materials Engineering and Concrete Cabrillo College ENGR45

  2. Sustainability & Materials Engineering • General Statistic - With less than 5% of the world’s population, the U.S. was responsible for about one-third of the world’s total material consumption in 1970-1995. Is this Sustainable? • Triple Bottom Line! Environment Society Economy

  3. Material Management: focuses on impact of life-cycle stages - “upstream and downstream” vs. Waste Management: focuses mainly on “downstream” RECOMMENDATIONS: Promote efforts to manage materials and products on a life-cycle basis. Accelerate the broad, ongoing public dialogue on life-cycle materials management. Sustainable Materials ManagementEPA Workgroup Reports

  4. Flow of Materials • Where do Materials Engineers “fit” into the production equation? • How much decision making “power” do MatEngrs have regarding the life-cycle of a material used in a product?

  5. What are sustainable building materials? Why would we use sustainable building materials? Answer… Partner up with the student next to you and discuss. Write down a few ideas… Question & AnswerSustainable Building Materials

  6. What’s in the Mix?Components of a Basic Concrete Mix • Composite Material: Aggregates and “Paste”/Binder • Aggregates: course (granite) and fine (sand) • Portland cement: mixture of many compounds (silicates+) • Water: H2O • Curing: The importance of HydrationHydration commences as soon as the cement contacts water. A cement particle grows, spreads and adheres to other growing particles - causing stiffness, hardening and strength development.

  7. Desired Properties of Concrete • Strength - Compressive, Shear, Tensile • Durability - resistance to freezing and thawing • Corrosion - resistance to chemicals • Permeability and Watertightness

  8. Fly AshA Sustainable Building Material? • Fly ash: post-industrial waste product from coal-burning power plants. • Used as part of “paste” in concrete (est.1970’s) • Included in >50% of all US ready mixes (ex. Quickcrete) • Added for increased durability of concrete related to corrosion resistance (marine exposure) = enhances life cycle of concrete. • Slower rate of strength development (56-day vs 28-day) • Cheaper than Portland cement • Potential to zero-out carbon emissions created in order to make cement

  9. QUESTIONSIf you were… … an Engineer would you specify it? Why or Why not? … a contractor would you use it? Why or why not? … a homeowner or builder would you use it? Why or why not? … a regulator or policy maker, would you mandate it’s use? Why or why not? Question & AnswerFly Ash • Answer… Partner up with the student next to you and discuss. Write down a few ideas…

  10. Fly Ash - RevisitedA Sustainable Building Material? • Fly ash (before use as a binder in concrete) has the potential to leach mercury, cadmium, selenium and arsenic into ground water. • EPA is/was proposing two options:(A) place a hazardous waste label on fly ash OR(B) place a non-hazardous waste label on fly ash and let individual states handle the transportation and disposal issues

  11. Question & AnswerFly Ash - Revisited QUESTIONSIf you were… … an Engineer would you specify it? Why or Why not? … a contractor would you use it? Why or why not? … a homeowner or builder would you use it? Why or why not? … a regulator or policy maker, would you mandate it’s use? Why or why not? • Answer… Partner up with the student next to you and discuss. Write down a few ideas…

  12. Other Examples • Other materials with similar issues? Are these materials sustainable? • Polymers • PBA’s in Nalgene bottles • Off-gasing from artificial turf • Metal • Lead in drinking water valves/taps • Lead in cooking pots used to make candy

  13. Concrete Proportioning Let’s get to it…turn to page 272

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