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Session #3 Asphalt 103- Materials: Basics of RAP, Usage and Specifications

Session #3 Asphalt 103- Materials: Basics of RAP, Usage and Specifications. Colorado DOT RAP Specifications. Roy Guevara CDOT Asphalt Pavement Program Rocky Mountain Asphalt Conference February 2009. Reasons For Using RAP. Energy and Cost Savings

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Session #3 Asphalt 103- Materials: Basics of RAP, Usage and Specifications

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  1. Session #3Asphalt 103- Materials:Basics of RAP, Usage and Specifications

  2. Colorado DOT RAP Specifications Roy Guevara CDOT Asphalt Pavement Program Rocky Mountain Asphalt Conference February 2009

  3. Reasons For Using RAP • Energy and Cost Savings • 1 ton of RAP conserves 200,000 BTU’s of Energy • Aggregate mining, processing & delivery • Asphalt refining & delivery • Conserve our valuable natural resources. • Environmentally friendly

  4. CDOT RAP Specifications Highlights Standard Special Revision of Section 401 • Use on projects with voids acceptance of hot mix asphalts • May be used on other projects as determined by the Region Materials Engineer

  5. CDOT RAP Specifications Highlights Standard Special Revision of Section 401 • 20% RAP allowed on top lifts • 25% RAP allowed in all other lifts • Contractor may use more RAP if they follow AASHTO MP-1 specifications • Contractor must have an approved mix design for the amount of RAP to be used.

  6. CDOT RAP Specifications Highlights Standard Special Revision of Section 401 Additional Conditions: 1. Approved Quality Control Plan detailing how RAP will be processed and controlled. • RAP Processing Techniques • Control of RAP Asphalt Binder Content • Gradation testing 1/1000 tons of HMA

  7. CDOT RAP Specifications Highlights Standard Special Revision of Section 401 2. Processed RAP must be 100% passing the 1 ¼” sieve (31.5mm) 3. If RAP content is >20%, binder is bumped down one grade on both the high and low ends.

  8. Bumping Grade Example Plans require a PG 64-22. If >20% RAP is used, the binder is bumped down to a PG 58-28

  9. CDOT Binder Grades CDOT Grade Bumped Down Available? PG 76-28 PG 70-34 No PG 64-28 PG 58-34 Yes PG 64-22 PG 58-28 Yes PG 58-34 PG 52-40 No PG 58-28 PG 52-34 No

  10. Tiered approach • <20% No binder changes • 20% - 25% Grade bump down both high and low end • >25% Use blending charts

  11. CDOT RAP Specification Highlights • Section 401.22 “When asphalt cement is a separate pay item, the amount of asphalt cement contained in RAP material will NOT be measured or paid for but shall be included in the work”

  12. CDOT RAP Specification Highlights • Project Special Provision 202 • RAP Value Engineering Cost Proposal • Indicate the amount of RAP millings CDOT will retain • If Contractors desire to retain all or more than what is allowed in the contract, Contractor can submit VECP

  13. RAP Task Force Changes • Increased RAP usage from 15% to 20% allowed in top layers • RAP mixes treated like virgin mixes -2 mix designs no longer required -subsection 401.02(b): one strike you’re out language was deleted. • RAP allowed on Gradation Acceptance projects at Region Materials Engineer’s discretion

  14. RAP Task Force Changes • New procedure outlining process for mix designs that use millings from same project (CPL 5145) • RAP Sampling • Sample preparation • Test Samples • RAP Processing Testing

  15. CDOT RAP Usage Statistics RAP is usually allowed on most voids acceptance and non SMA projectsNo explanation for drop in use in 20072008 was first season that did not require virgin mix design and “1 strike you’re out” language was deleted.

  16. CDOT RAP Survey Findings • Survey found that there were only minor obstacles for allowing or using RAP • For CDOT, testing manpower and high profile projects were barriers for allowing RAP • For Contractors, remote areas with no RAP piles and lack of equipment were barriers

  17. 2008 Ontario Ministry Survey • 15% to 20% RAP allowed on top lifts • 20% to 40% RAP allowed for other lifts • Contractors tend to use only 20% to 25% even when higher levels are allowed

  18. 2008 Ontario Ministry Survey • 7 agencies do not permit RAP use on top lifts of heavily traffic areas (>30 million 20 year design ESALs) • Bad experience • Lack of experience/ confidence with RAP in the wearing course • 2 agencies do not permit it at any layers for heavy traffic areas

  19. CDOT RAP Uses • In asphalt mixes • Hot and Cold Recycling • Shouldering • As a base • CDOT Maintenance yard parking lots

  20. Thank you

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