1. An Introduction to
RAS

2. 3 Aspects of RAS
Economics
Application Science

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. Typical Asphalt Shingle
Composition
Granular/aggregate surfacing
Waterproofing asphalt
Asphalt-impregnated mat (fiberglass
or organic felt)
Waterproofing asphalt
Fine granular/aggregate backing
Component Newer, fiberglass-mat Older, organic-mat
shingles (%) shingles (%)
Asphalt cement 19-22 30-36
Mat 2-15 2-15
Mineral granules/aggregate 20-38 20-38
Mineral filler/stabilizer 8-40 8-40
Source: Townsend, T., Powell, J., and Xu, C., Environmental Issues Associated With Asphalt Shingle
Recycling, Construction Materials Recycling Association, Asphalt Shingles Recycling Project, US EPA
Innovations Workgroup

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. 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. Science
• Mix design considerations:
– Blended asphalt grade
– RAS asphalt content
– RAS aggregate content and gradation
– Deleterious materials

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. 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. Application
• Regulations
– Current regulations allow 5% RAS by volume of
mix
– Can also be regulated by 30% of the binder
replacement

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. Economics
• Approximant cost of RAS Replacement Binder
– $100 - $110 per ton
• Cost of RAS Feeder bin implementation
– $20,000 - $30,000

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. 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. 3 Aspects of RAS
Economics
Saves $
Application Science
Simple Better product