Nsr webinar


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Nsr webinar

  1. 1. An Introduction to RAS
  2. 2. 3 Aspects of RAS EconomicsApplication Science
  3. 3. Science Todd Scholz, Ph.D., P.E.• B.S. (‘87), M.S. (‘89), Ph.D. (‘95), Civil Engineering• 25+ years in the industry: – Engineering trainee/technician (3 mo. at ODOT, 6 mo. at FHWA) – 17+ years in academia (Oregon State, Michigan Tech, University of Nottingham) – 8+ years in consulting – 5+ years working directly with major construction companies (Kiewit, Granite)• Consulting: highway & airfield pavement evaluation/design/rehabilitation projects; city/county/airport pavement management systems; forensic investigations; short courses (training); quality control• Research: highway materials (aggregates, asphalt, bituminous mixtures, concrete mixtures); recycled asphalt shingles (RAS)
  4. 4. Typical Asphalt Shingle Composition Granular/aggregate surfacing Waterproofing asphalt Asphalt-impregnated mat (fiberglass or organic felt) Waterproofing asphalt Fine granular/aggregate backingComponent Newer, fiberglass-mat Older, organic-mat shingles (%) shingles (%)Asphalt cement 19-22 30-36Mat 2-15 2-15Mineral granules/aggregate 20-38 20-38Mineral filler/stabilizer 8-40 8-40Source: Townsend, T., Powell, J., and Xu, C., Environmental Issues Associated With Asphalt ShingleRecycling, Construction Materials Recycling Association, Asphalt Shingles Recycling Project, US EPAInnovations Workgroup
  5. 5. Science• RAS sources: – Manufacturer waste – Tear-off shingles• Typical RAS composition: – Shredded asphalt shingles – Minor amounts of construction waste (typically plastic, wood, metal, paper)
  6. 6. Science• Effect of RAS on asphalt grade: – RAS asphalt blends with paving grade (virgin) asphalt (e.g., PG 64-22) resulting in a stiffer blended asphalt – Improves resistance to deformation and rutting – Theoretically improves resistance to moisture damage – Decreases resistance to cracking
  7. 7. Science• Mix design considerations: – Blended asphalt grade – RAS asphalt content – RAS aggregate content and gradation – Deleterious materials
  8. 8. Application• Rodney Pierce• Heritage Environmental Services, LLC. --Director of Sustainable Solutions• 15 years in the Environmental Industry the last 6+ years in environmental/recycling innovation and product development• Graduate of Purdue University, West Lafayette, IN., B.S. in Chemistry & Biochemistry
  9. 9. Application• Using RAS – Suggestion would be to Incorporate a separate Recycle bin to feed RAS – RAS is NOT a RAP replacement; RAS changes the Fine Aggregate Structure and a new mix design is necessary when using RAS – Sensitivity of weight belt and monitoring feed rate – Change opening in bin to allow less into mix – RAS can also be premixed with RAP or sand prior to mixing process
  10. 10. Application• Regulations – Current regulations allow 5% RAS by volume of mix – Can also be regulated by 30% of the binder replacement
  11. 11. Economics• Cost of Virgin Binder – $650.00 per ton• Cost of RAS – $25.00 per ton• Asphalt content of of RAS from tear-off – 22%-26% per HES test results
  12. 12. Economics• Approximant cost of RAS Replacement Binder – $100 - $110 per ton• Cost of RAS Feeder bin implementation – $20,000 - $30,000
  13. 13. Economics• Break Even Point Analysis – 450 tons of RAS replacement binder to break even with implementation costs – After purchase and usage of 450 tons saving $66.00 per ton • Total savings yield is $29,700
  14. 14. Economics• RAS benefits for Commercial and Private work• Using softer asphalt can allow more RAS to be added to a mix• RAS + RAP mixes with >40% binder replacement are possible• Where RAP is not plentiful, RAS is a good alternative.
  15. 15. 3 Aspects of RAS Economics Saves $Application Science Simple Better product