Cold-In-Place Recycling (CIPR) Sampling and Testing Protocol Development

The Utah Department of Transportation (UDOT) is in the middle of updating their laboratory design and field testing protocols and controls for both Cold-in-place Recycling (CIR) and Full-depth reclamation (FDR) procedures for pavement rehabilitation. Part of the update of these practices includes the development of new end-result performance procedures that can be used in the lab and field to get good materials information in a timely manner to aid in the evaluation of the construction processes and determine proper opening times to traffic. To develop these procedures, field data must be collected from projects to use in getting a better understanding of how the materials react and perform during the construction and placement processes. The use of CIR and FDR to reclaim and rehabilitate pavements has been shown to significantly reduce costs (25% TO 33%) compared to that of using virgin materials. The current versions of these tools utilize a solventless emulsion that provides for significantly shorter curing times and earlier opening to traffic. UDOT has fully adopted these pavement rehabilitation practices, however the current procedures used to design, control and evaluate the construction of these materials are time consuming and expensive, and have not been able to prevent some pavement failures due to inadequate timeliness and applicability of test results. The ultimate performance of the CIR material is defined by the type and amount of emulsion added to the milled material. The design of the material must balance the need of more emulsion to achieve strength and reduce raveling with the need for less emulsion to prevent rutting. Current laboratory test procedures can account for this but cannot currently be translated to field applications due to the complexity of the testing. Field control needs to be based on controlling simple characteristics of the mix and production that affect the ultimate performance and field curing curve. The following factors are believed to affect the ultimate strength and curing curve of field processed mix. These factors are generally controlled by the contractor based on an "art" approach where experienced personnel make a field judgment call on the time of paving, added materials and opening to traffic. UDOT would like to begin quantifying any that can be appropriately tested. To identify those that can be quantified, detailed data must be collected and reviewed to determine patterns and variability within field production. Efforts must be made to separate as many of the variables as possible, requiring significant data. (1) temperature/humidity/time, (2) moisture content (controllable, can it be managed?); (3) emulsion content (controllable, can it be managed?); (4) compaction (Controllable); (5) gradation (partially controllable…added expense); (6) pavement materials (controllable through project selection); (7) pavement consistency (controllable through project selection); and (8) traffic (controllable through project selection). Through industry committees, UDOT has already identified several possible field test protocols that could very effective in providing appropriate project control information giving this research a very high possibility of being successful. UDOT's ultimate goal for the program would be a simple performance specification that contains the following basic pieces: (1) You have X time to open to traffic; (2) You must have Ci compressive strength and Ti tensile strength at opening to traffic; and (3) You must have Cf compressive strength and Tf tensile strength at ultimate acceptance. The opening to traffic decision is also expected to be based on a combination of rutting and raveling tests to verify that the field mix has achieved sufficient stability so as to withstand traffic. The importance of the research lies in the possible loss of very cost-effective rehabilitation practices due to a lack of proper materials control practices and subsequent failures of the processes. CIR and FDR have become increasingly important tools for Pavement Management Engineers to use in the rehabilitation of pavements based on continued constrictions in blue-book funding. CIR and FDR are tools that meet purple-book/rehabilitation guidelines.


    • English


    • Status: Active
    • Contract Numbers:



    • Sponsor Organizations:

      Utah Department of Transportation

      4501 South 2700 West
      Project Development
      Salt Lake City, UT  USA  84114-8380
    • Project Managers:

      Nichol, Kevin

    • Performing Organizations:

      CME Transportation Group

      2800 S Redwood Rd
      Salt Lake City, Utah  USA  84119-2375
    • Principal Investigators:

      Biel, Timothy

    • Start Date: 20110607
    • Actual Completion Date: 20140630
    • Source Data: RiP Project 33615

    Subject/Index Terms

    Filing Info

    • Accession Number: 01472093
    • Record Type: Research project
    • Source Agency: Utah Department of Transportation
    • Contract Numbers: 11-9137, UT11.106
    • Files: RiP
    • Created Date: Feb 13 2013 1:00AM