ARRA Semi-Annual Meeting Minneapolis, MN October 16-19, 2017

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2 Quality Testing for In-Place Recycling NCHRP Project 9-62 Brian Diefenderfer, Ph.D., P.E. Virginia Transportation Research Council

3 Pavement Recycling Viable techniques for pavement rehabilitation and new construction Cost savings Greenhouse gas emissions reductions Other benefits However, there are challenges

4 Two Examples Rapid quality testing of the constructed product Contractor: difficult to demonstrate that material meets design intent Agency: difficult to make time-critical identification of acceptable material Deciding when a recycled layer can be surfaced or opened to traffic

5 NCHRP Project 9-62 Rapid Tests and Specifications for Construction of Asphalt-Treated Cold Recycled Pavements Research team Brian Diefenderfer, Principal Investigator Dave Jones, Co-PI Adam Hand, Gerardo Flintsch, Ben Bowers Industry Technical Support Team (!!!!)

6 NCHRP Project 9-62 Objective Develop or identify a test method(s) or protocol(s) to determine when a recycled layer can be surfaced or trafficked Scope Asphalt-based recycled materials FDR, CIR, CCPR

7 NCHRP 9-62 Timeline Phase Activity Start End 1 Literature review, stakeholder survey, propose tests 2 Lab trials of proposed tests 3 Field trials of proposed tests June 2017 November 2017 November 2017 December 2018 January 2019 April 2020

8 Phase 1 - Literature Review Nuclear density and standard compaction Often used for material quality Experience has shown poor density can lead to poor quality Relationship to design? Acceptance Compare to mix design or field proctor?

9 Phase 1 - Literature Review Moisture content Often used to assess time to traffic or surfacing Relationship to long-term performance? Proof rolling is seldom used Needs standardization

10 Phase 1 - Literature Review Typical surfacing or opening to traffic categories: Wait a predetermined amount of time Measure moisture content Waiting is inefficient Layer may be ready before time requirement Weather changes Is moisture correlated to quality?

11 Phase 1 - Stakeholder Survey 4 sections Respondent information Suggestions for tests not widely used / published Current tests to identify state of the practice Help with identifying future projects for Phase 3 How fast is rapid? goo.gl / i8v75v

12 Phase 1 - Stakeholder Survey Distribute to AASHTO state representatives, AASHTO Committee on Materials and Pavement, appropriate TRB committees, and ARRA Need help to identify local agencies goo.gl / i8v75v

13 Other Phase 1 Products Summary of tests identified from the literature and stakeholder survey Experimental design for Phase 2 (lab) Prioritize tests based on: test time, cost, availability of equipment, precision and bias of test, applicability to all recycling processes

14 Anticipated Test Categories Penetration / deformation resistance Raveling resistance Density Stiffness Moisture

15 Phase 2 Lab Trials of Proposed Tests Lab testing will be conducted at two scales Slab scale Slab specimens prepared in the lab Larger than marshall or gyratory specimens Full scale limited verification testing of most promising tests Virginia & California Heavy Vehicle Simulator (HVS) test sites

16 Phase 2 Lab Trials of Proposed Tests Proposed variables include: Recycling process Foamed asphalt and emulsified asphalt With and without cement, lime, etc. Curing ages Gradations Densities Final selections coordinated with NCHRP

17 Other Phase II Products Ruggedness and interlaboratory study of proposed tests (if they do not already exist) Development of AASHTO standards for proposed tests Experimental design for Phase 3 (field)

18 Phase 3 Field Trials At least 6 field projects around the US Conduct test plan using those tests identified during lab study Not possible to cover all combinations Will address the most prevalent Final selections coordinated with NCHRP

19 Other Phase 3 Products Document lessons learned Proposed guide specification in AASHTO format Final report (February 2020) Project ends May 2020 Implementation

20 Thank you!