This document discusses how asphalt pavement is a sustainable material. It can be recycled and reused through practices like reclaimed asphalt pavement (RAP) to construct new pavements. Asphalt also has a lower carbon footprint compared to other pavement materials since it requires less energy to produce and construct. Additional sustainable practices for asphalt pavements include warm mix asphalt, which further reduces energy usage and emissions, and porous asphalt, which helps manage stormwater runoff. These sustainable features make asphalt pavement a perpetual material that can be rehabilitated and reused multiple times over its lifetime.

1. Greening the Blacktop Going Green with Sustainable Asphalt RAP, Recycling, Energy and the Carbon Footprint

2. Overview Why Asphalt is sustainable Perpetual Pavements Carbon Footprint RAP & Recycling Warm Mix Asphalt Porous Asphalt Energy & Emission Reductions

3. Why Asphalt is Sustainable

4. Sustainable Pavements

5. Sustainable Pavement Durability… Asphalt is the Perpetual Pavement Road itself doesn’t wear out Simple, fast maintenance Reclaimed…is then reused Total removal/reconstruction not needed

6. Sustainable Pavement Requires less energy to construct an asphalt pavement Per ASCE…20% less Less energy consumed by public Less maintenance keeps traffic moving

7. Max Tensile Strain Pavement Foundation High Modulus Rut Resistant Material (Varies As Needed) Flexible Fatigue Resistant Material 75 - 100 mm } 100 mm to 150 mm Zone Of High Compression Perpetual Pavements 40-75 mm STONE MATRIX ASPHALT, OGFC or Superpave

8. Rehabilitation { 50 - 100 mm Structure Remains Intact Possible Distresses Top-Down Fatigue Thermal Cracking Raveling Solutions Mill & Fill Thin Overlay Mill Surface – Use for RAP High Quality Stone Matrix, OGFC or Superpave 20+ Years Later

9. Carbon Footprint

10. What the heck is a Carbon Footprint?

11. A carbon footprint is defined as: The total amount of greenhouse gases produced to directly and indirectly support human activities, usually expressed in equivalent tons of (CO2) Doesn’t segregate GHGs Environmental Sustainability

12. Climate Registries Organizations that collect and compile emissions data generally voluntary (CA, NE US) Encourages voluntary early actions to increase energy efficiency and decrease GHG emissions

13. What is a Greenhouse Gas? Gases that trap heat in the atmosphere – Allows us to live here Some occur from nature, others from anthropogenic activities

14. What is a Greenhouse Gas? Principal greenhouse gases entering the atmosphere from human activities are: Carbon dioxide (CO2) Methane (CH4) Nitrous Oxides (N2O) Fluorinated gases (HFCs & PFCs)

15. Regulatory Concerns Efforts to make you report emissions Benefits of being ahead of the wave Demonstrates concern for the public and the environment

16. Opportunities to Reduce Emissions Sustainable Pavements Warm Mix RAP Plant O & M Truck and other equipment maintenance

17. RAP & Recycling

18. Recyclability Asphalt is the No. 1 recycled material Biggest Re-user 1995 FHWA Report to congress 90 Million tons reclaimed 80% recycled 2006 Contractor Survey ~69% reused in HMA ~27% other recycling <3% discarded

19. Why Recycle RAP into HMA? Best and Highest use Reduces demand for new materials Reduces carbon footprint Contains valuable materials Aggregate ~95% >$10/ton Asphalt ~5% > $400/ton Value >$29.50/ton (minus processing)

20. Shingles Shingles Materials used in HMA >20% asphalt binder Fibers Sand Usually 5% of mix Saves 1% binder > $6.00/ ton of HMA/WMA Tear-offs

21. Over the past two years, MoDOT has allowed contractors to put used shingles that have been removed from rooftops into their asphalt mix. The result is a very durable, more-rut resistant asphalt at a much lower price. The use of recycled shingles saves $3 to $5 per ton of asphalt. That may not sound like much at first, but consider this: a typical resurfacing project would use about 30,000 tons of asphalt, for a savings of $90,000 to $150,000.

22. Other Recycled Materials Crumb rubber (from tires) Steel slag Glass

23. Warm Mix Classifications

24. Lower Temperature Advantages Lower energy consumption (≈30%) Lower plant wear Decreased binder aging Early site opening – Return to user Cool weather paving Compaction aid for stiff mixes Cooler working conditions

25. Porous Asphalt

26. What are Porous Pavements? Open-Graded HMA/WMA ~ 2 ½” ½” Agg. (#57) ~ 1” – 2” Thick Clean Uniformly Graded 2”-3” Crushed Agg. (#2) – 40% Voids Non-Woven Geotextile Uncompacted Subgrade

27. Porous Pavement Stormwater quality improved with: Porous pavement, and Open Grade Friction Course Can eliminate the need for stormwater structures

28. Water Quality

29. Walden Pond 1977 1997 Report: “Twenty years later, a long time for one paving job on that busy parking lot, it still looks good and works well.” 2008

30. Energy & Emission Reductions

31. Warm Mix Will dominate the market in < 5 years Reduced energy consumption Reduced emissions No hazardous fumes/worker exposure Plants compatible in congested areas No odors The sooner the better!

32. Remedial Efforts Use the components of the carbon footprint to identify problem areas Take action and make adjustments to reduce emissions Switch to Warm Mix sooner Conduct energy audits Take action to reduce energy

33. Energy Use by Road Material Type Colas Group Data

34. Reduced Energy Consumption Energy Audits DOE Software Use RAP Warm Mix Can Reduce Energy by Cover the Aggregate ⅓

35. Why is Asphalt Sustainable 100% Recyclable Can use other recycled materials Low carbon footprint pavement Long life & fast resurfacing Warm-Mix Asphalt Porous pavement for stormwater

36. NAPA Theme RAP + Porous + Warm Mix + Perpetual Pavements = Sustainability

37. Summary & Review Why Asphalt is sustainable Perpetual Pavements Carbon Footprint RAP & Recycling Warm Mix Asphalt Porous Asphalt Energy & Emission Reductions

38. Questions?