Feasibility of Cold Central Plant Recycling Asphalt Mixtures for Airports: Task 1 Report

This report summarizes the work completed in Phase 1 of a study to investigate the feasibility of using cold central plant recycled (CCPR) asphalt mixtures on airport pavements. Tasks within this phase included a literature review, laboratory and limited accelerated wheel load testing, development of a procedure for designing airport pavements that include a recycled layer, development of test plans for accelerated pavement testing at the FAA’s William J. Hughes facility, development of specifications for constructing the cold central plant recycled layers on the test track, and development of just-in-time training for all personnel participating in the construction of the test track. The specifications and just-in-time training deliverables will be revised for general use based on observations and feedback from construction of the test track. The primary conclusions from the study include the following: (1) there is limited published literature on the use of cold recycled layers on commercial airport pavements, and successful implementation has been reported at 10 airports in Australia, where cold recycling was chosen over traditional remove-and-replace procedures because of speed of construction, lower environmental impact, and lower cost, (2) the FAA’s FAARFIELD design software in its current form cannot be used to design airport pavements that include a recycled layer, (3) current approaches for designing highway and airport pavements that include a recycled layer do not accurately model the behavior/performance of that pavement, approaches developed for highway designs cannot be readily adapted for airport pavements given the significantly higher gear loads and tire pressures, and a new approach was therefore required, and (4) the FAA does not have specifications for producing cold central plant recycled mixes or constructing layers with cold central plant recycled materials. Specifications therefore needed to be developed. A test plan, specification documents, and just-in-time training have been developed for the accelerated pavement testing component of the study. The test plans include test section layout, designs, and instrumentation, as well as the Heavy Vehicle Simulator trafficking plans. The specifications are consistent with the FAA’s Standard Specifications for Construction of Airports (AC 150/5370-10H, 12/21/2018) and include mix design procedures.