One of the more serious problems that can occur on HMA airfield pavements is the delamination of hot mix asphalt (HMA). Several instances have been documented where pavements that have not previously been identified as having delamination problems have experienced significant damage when subjected to an application of jet blast or other horizontal loading from an aircraft. The presence of undetected delamination and/or discontinuities in asphalt pavement also provides paths for moisture damage and development of other distresses such as foreign object debris (FOD), slippage cracks, pavement deformation and reduction in pavement strength. The types of distress associated with delamination typically require the need for continual maintenance until major corrective actions are taken. A rapid nondestructive test method is needed to determine the existence and extent of delamination and/or discontinuities in asphalt pavements.

Objectives

The objective of this study is to provide a comprehensive procedure and guidance to identify the presence and extent of HMA delamination in airport pavements. The procedures developed in this study shall concentrate on the capability of identifying delamination and discontinuities within the upper 5 inches of the asphalt pavement but not be limited to the upper 5 inches. The selected contractor shall investigate common conditions of past instances of major damage to airport HMA pavements resulting from delamination and determine key indicators that may be used to identify potential areas of delamination. In addition, the contractor shall identify existing non-destructive test (NDT) procedures and/or equipment that have been used to address the problem and determine if these methods, modifications of these methods, or new methods should be pursued to provide a rapid, effective way to determine if pavements have delamination and present a risk of significant damaged by jet blasts or other aircraft operations. Although the causes for delamination and discontinuities of asphalt pavement are important, no significant time is expected to be devoted to that element in this project. The main objective of this study is to identify and develop non-destructive procedures that are capable of locating areas of delamination and discontinuities.

This study is divided into two phases. Phase I will consist of a literature review of the historical records of pavement delamination failures from jet blasts, methods presently used to identify delamination and discontinuities, assessment of the applicability and effectiveness for use in airfield pavements, and proposal of a comprehensive study/experimental plan to validate recommended approaches. Phase II shall consist of modifications, if needed, to the recommended procedures/equipment and conducting experiments to verify that the procedure is applicable to airfield HMA pavements.

Specific conditions for airfield pavements that should be considered are:

1. Locations within the airport facility that have the greatest potential for damage to asphalt pavements from jet blast to occur.
2. Relationships to geographical and climatic conditions and/or weather events at airfields that may contribute to the potential for delamination damage to occur.
3. Typical airport operational constraints to include but not limited to limitation of time availability to conduct non-destructive tests on airport pavements.
4. Pavement structure and operational characteristics that may enhance the possibility of delamination and subsequent major damage caused from jet blast.

Products

The products for this project shall consistent of: (1) comprehensive review and documentation of existing procedures and equipment used for identifying delamination and discontinuities in HMA pavements; (2) development and documentation of a rapid, economical test to be used to determine the presence of delamination of HMA pavements; and (3) documented field verification of recommended non-destructive testing procedures/equipment. These products shall be developed by addressing the following tasks:

Task 1 -- Literature search of case histories of instances where jet blast damage to asphalt pavements has been exacerbated by delamination. The search shall include a review of existing methods and equipment used to identify delamination and summary of common causes for delamination damage and distress present before the jet blast damage occurred.

Task 2 -- Assessment of the potential use of existing NDT methods for airfield HMA pavements application. The result of this task shall be a comprehensive table of existing methods and equipment used for identifying the presence of discontinuities and delamination in asphalt pavements. The table shall contain but not be limited to the following items:

1. Equipment limitations and capabilities
   1. Depth of effective applicability
   2. Speed of data collection and area coverage
   3. Speed of data analysis and availability of results
   4. Availability and accessibility of equipment
   5. Accuracy of results
   6. Interpretation/analysis requirements such as propriety software, data processing capacity, etc
   7. Equipment reliability
2. History of procedure/equipment use
3. Rationale used to assess the applicability to airports
4. Ability to implement procedures/equipment by personnel outside the research team

Task 4 -- Develop a work plan for field verification of test methods and equipment.

Task 5 -- Provide a report outlining findings to date and proposed future actions for this research. The report is expected to be presented to the technical panel at a mutually agreed upon location approximately 6 months after award. The purpose of this meeting is for the technical panel to provide comments and direction on the completion of Phase I and approval for work to be conducted in Phase II.

Task 6 -- Upon approval of the Phase II work plan by the technical panel, conduct laboratory/field testing as indicated in the work plan.

Task 7 -- Provide draft final report for panel review and comments. The final report shall contain all products to be delivered under this study. The technical panel will provide comments within one (1) month after receiving drafts.

Task 8 -- Make revisions to the draft final report and other documents per panel comments. Provide the final report and recommended NDT test protocol. Submit camera ready copy of the final documents and an electronic copy in press quality PDF format.

All written documentation will be prepared using Microsoft Word unless otherwise stated. All reports will be the property of the AAPTP and Auburn University and will be supplied in a format that complies with the FAA's Section 508 requirements for electronic documents.

Proposal Evaluation Criteria

1. Experience of the research team and organization in developing and implementing NDT procedures and equipment for asphalt pavements.
2. Understanding of the problem statement, proposed approach to accomplish the tasks outlined in the request for proposal and allocation of manpower.
3. Demonstrated abilities and experience of research team to understand airport operational and technical aspects of the project.
4. Ability to access specialized equipment/procedures to conduct field evaluation/verification in Phase II of the project.

The deliverable products for this project shall include:

1. Interim report (Task 5)
2. Final Work Plan for Phase II (Tasks 4 & 5)
3. Final Report and Test Protocols (Task 8)

Progress Reports

Quarterly progress reports (one hard copy and an electronic copy in Microsoft Word format) are required from the research agency and are to be prepared on the basis of calendar quarters. The research agency will mail the report directly to the AAPTP and will e-mail each of the members of the technical review panel a copy of the progress report. Each report will include a cover letter and the following:

1. a clear and complete description of the work performed on each task during that quarter;
2. an outline of the work to be accomplished during the next quarter;
3. a description of any problem(s) encountered or anticipated that might affect the completion of the project within the time and fiscal constraints recommended;
4. potential solutions to problems identified in (c) if any exist.

Report Format

The formats for the Interim and Final reports are provided under "Research Process."

Contractual Information

Funds Available: $190,000

Contract Time: 18 months (includes 1 month for AAPTP to review and for the contractor to revise the final report.)

Staff Responsibility: Monte Symons, 334-844-4964, symonmg@auburn.edu

Proposals Due: November 9, 2007

Submit Proposals To: AAPTP, 277 Technology Parkway, Auburn, AL, 36830

Authorization to Begin Work: January 2, 2008 -- estimated