IPRF Project FAA-01-G-002-3

Innovative Rehabilitation of Pavement for Light-Load Aircraft Traffic (Aircraft < 30,000 Pounds)


A construction technique, known commonly as "Ultra-Thin Whitetopping" (UTW), can be used for the rehabilitation of flexible pavement. The rehabilitation is accomplished by the placement of a thin portland cement concrete overlay (2" to 4" thickness) on existing roads, streets or, in the most common form, intersections. UTW is not, however an approved FAA standard for pavement rehabilitation within the Airport Improvement Program (AIP) guidelines. One of the aviation community concerns is the durability of the bond between the asphalt pavement and the concrete overlay. Unlike conventional whitetopping, UTW relies upon the bond of the concrete to the asphalt for the load capacity. The UTW design has been validated by simulating truck traffic using accelerated load testing. But, the effects of the environment on the bond between the concrete and the asphalt have not been validated for the long term.

This project will involve doing field studies and performing laboratory testing to determine how the environmental factors affect the bond. Laboratory evaluations will simulate the long term by accelerating the time scale. The degradation of bond of the concrete to the asphalt will be determined and compared to the cyclic temperature extremes and exposure to numerous freeze thaw cycles. The goal of the project is to determine if there is a loss of the bond between UTW and existing asphalt surfaces and if the degradation is significant enough to limit use of the rehabilitation technique for pavement trafficked by light load aircraft (gross weights of 30,000 pounds and less).


The project will be accomplished along two Tracks.

Track 1 is to be a field study of in-service UTW projects. The field study will concentrate on documenting the in-service performance of the asphalt-PCC bond. There will not be any destructive testing in Track 1. A list of UTW projects from the Midwest, Florida and Tennessee will be provided to the contractor by the IPRF. The list is not intended for general distribution and will be given to the team selected to do the work. The project list is intended to assist the research team in locating and documenting projects. The research team is expected to determine if there are other projects that should be included in the field study. The research team will coordinate with the IPRF to review the applicability of highway-based UTW research to the airport environment. The field study should quantify the method of asphalt pavement surface preparation for each of the projects included in the study. Results of the field study, including the research team's conclusion about the effectiveness of the bond, will be presented in a stand-alone report. The Track 1 team will comment on the test plan prepared under Track 2 and include specific recommendations for the accelerated environmental studies.

The Track 1 investigation will include a review of the background engineering documents and related studies for the UTW paving at the Savannah-Hardin County Airport, Savannah, TN. The pavement includes a runway, 2 taxiways, and a GA apron. The Track 1 team will accomplish a visual survey of the pavement to validate the background documents. The Track 1 team will identify the parameters that are considered critical to the evaluation of long-term performance of the pavement. The Track 1 team will make recommendations concerning the long-term observations. The IPRF will distribute documents relevant to the pavement systems at Savannah-Hardin County Airport as a part of the award of the contract. Questions about the contents of the documents that are available shall be directed to the IPRF Project Director or the IPRF Principal Investigator.

Track 2 will begin with the preparation of a test plan for evaluating environmental effects on the long-term bond between asphalt concrete and the UTW. The minimum environmental extremes that will be considered will be wet/dry, freeze/thaw, and temperature. The test plan should attempt to simulate the extremes found in different regions of the continental U.S. The test plan will not be submitted for IPRF review until comments from the Track 1 group are included in the plan. The Track 2 team will not be required to include all the comments of the Track 1 study but reasons for not including Track 1 recommendations will be required. The test plan will be completed before the Track 1 report is presented in final form. The test plan will be implemented only after submittal to and review by the IPRF. For planning purposes, the IPRF review period will not exceed thirty days.

Special Considerations for Track 2:

  1. The success of Track 2 will depend in large part on the laboratory equipment used in the research. Therefore proposals must include a description of the laboratory equipment. Special instructions for including the equipment description in the proposal are provided in the Instructions for Preparing Proposals for Project FAA 01-G-002-3.
  2. The technical panel that will review the proposal will expect to see in the proposal viewpoints, based upon the experience of the research team, for two issues.
    • Age of asphalt -UTW overlays are not placed on new asphalt. UTW is a rehabilitation technique. The test plan must include a description about how the research will include aged asphalt pavement as a test specimen.
    • Edge restraint - UTW panels are typically interior panels. The proposal must include a discussion about the necessity to include edge restraint in the environmental test for bond.

Proposals will be accepted for Track 1 only, Track 2 only or both Track 1 and Track 2. Proposals must clearly state if they are for Track 1, Track 2 or both. The IPRF retains the right to award separate contracts for Track 1 and Track 2 to different research groups, agencies or individuals. The IPRF will coordinate activities if separate contracts are awarded.


The Track 1 Team will make recommendations to the Track 2 Team concerning any testing recommended to be included intended to aid in the evaluation of performance of the pavement at the Savannah-Hardin County Airport. The Track 1 Team shall provide a report to the IPRF that documents the baseline conditions of the pavement and include recommendations for the IPRF to accomplish the long term observation of pavement performance.

The final products will be two (2) research reports that document the expected bond retention of UTW for a variety of environmental conditions (separate reports for Tracks 1 and 2.) The IPRF will specify the report format. The investigator will provide two originals and 25 copies of each manuscript including any artwork or photos. The publications will also be submitted in an electronic format compatible with industry recognized desktop computer publication software.

The investigator will be responsible for the preparing and submitting quarterly reports that describe the progress of the research effort. Reports will be due in the offices of the IPRF on the last day of the fiscal year quarter (i.e., last day of March, last day of June, last day of September, and the last day of December). The reports will be two pages maximum in a format that will be specified.

PROJECT DIRECTOR: Lawrence W. Cole, P.E., (847) 966-2272, lcole@pavement.com

Have Questions?
Contact Jim Lafrenz, Cooperative Agreement Programs Manager Phone: 202-842-1010

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