The AASHTOWare Pavement ME Design (formerly DARWin-ME) and the AASHTO Mechanistic-Empirical Pavement Design Guide Manual of Practice (MEPDG) (see Special Note A) provide a methodology for the analysis and performance prediction of new and rehabilitated pavements. The performance of these pavements is known to be influenced by the properties of the unbound layers in the pavement structure. These properties are often obtained from laboratory tests whose results do not always match those derived from field tests performed on the constructed layers. This difference will lead to inaccurate performance prediction and deficient design. There is a need to establish relationships between laboratory- and field-derived properties that can be used to obtain improved prediction of performance and design.
Over the years, the LTPP Program has collected laboratory- and field-derived data that are housed in the LTPP database (see Special Note B) and could be used to develop relationships between laboratory- and field-derived properties. However, there is a concern about the adequacy of available LTPP data to accomplish this task. Therefore, there is a need to assess the feasibility of using LTPP data for developing relationships that are appropriate for use in conjunction with the Pavement ME Design procedures to improve performance prediction and design. The findings of this assessment will help make a decision regarding the need for further research.
The objective of this research is to evaluate the feasibility of using LTPP data for developing relationships between laboratory- and field-derived properties of unbound materials used in pavements. The research shall be limited to those properties required for pavement design and analysis, in accordance with Pavement ME Design procedures.
Accomplishment of the project objective will require at least the following tasks.
The NCHRP is seeking the insights of proposers on how best to achieve the research objective. Proposers are expected to describe research plans that can realistically be accomplished within the constraints of available funds and contract time. Proposals must present the proposers' current thinking in sufficient detail to demonstrate their understanding of the issues and the soundness of their approach to meeting the research objective. Task descriptions are intended to provide a framework for conducting the research.
Task 1. Identify the properties of unbound pavement layers required for pavement design and analysis in accordance with Pavement ME Design procedures, and the data elements required for their estimation.
Task 2. Review the content of the LTPP database, and discuss availability of the data elements identified in Task 1.
Task 3. (1) Assess the adequacy of the data elements available in the LTPP database for estimating the material properties identified in Task 1, and (2) evaluate the feasibility of using available LTPP data for developing valid relationships between laboratory- and field-derived properties of unbound materials. The assessment shall address data quantity, ranges, quality, and other relevant features. If required, identify means for dealing with data shortage and other deficiencies (e.g., acquiring data from other sources, conducting additional laboratory or field tests, or removing some data).
Task 4. If found feasible, propose a plan for using the data available in the LTPP database to develop relationships between laboratory- and field-derived properties of unbound layers required for pavement design and analysis. The plan shall provide specific information on the different aspects of the required data elements (e.g., type, quantity, and quality), and present a detailed and specific approach for developing these relationships.
Task 5. Prepare a final deliverable that documents the entire research effort. All relevant data sets identified in this research (including those available from LTPP database and other sources) shall be provided, in an electronic format with schema, as an attachment to the final deliverable.
Note: Following receipt of the draft final deliverables, the remaining 2 months shall be for NCHRP review and comment and for research agency preparation of the final deliverables.
A. AASHTOWare Pavement ME Design and the Mechanistic-Empirical Pavement Design Guide: A Manual of Practice, Second Edition (Item Code MEPDG-2) are available from the American Association of State Highway and Transportation Officials (AASHTO), 444 N. Capitol Street, NW, Washington, DC 20001. The Pavement ME Design software will be provided to the selected contractor at no cost to the project. However, $2,000 should be allocated for charges in connection with installation and tech support.
B. LTPP database [LTPP Standard Data Release 31 (SDR 31)] is available at https://infopave.fhwa.dot.gov/.
C. A review meeting that includes a presentation by the research team to the project panel should be scheduled upon completion of Task 3.
D. Resumes of research team members must present relevant qualifications and be limited to no more than 2 pages for each member. The section on equipment and facilities (Item 8 in the proposal) shall describe relevant information and be limited to no more than 2 pages.
E. Proposals should include a task-by-task breakdown of labor hours for each staff member as shown in Figure 4 in the brochure, "Information and Instructions for Preparing Proposals" (http://onlinepubs.trb.org/onlinepubs/crp/docs/ProposalPrep.pdf). Proposals also should include a breakdown of all costs (e.g., wages, indirect costs, travel, materials, and total) for each task using Figures 5 and 6 in the brochure. Please note that TRB Cooperative Research Program subawards (selected proposers are considered subawards to the National Academy of Sciences, the parent organization of TRB) must comply with 2 CFR 200 – Uniform Administrative Requirements, Cost Principles, and Audit Requirements for Federal Awards. These requirements include a provision that proposers without a "federally" Negotiated Indirect Costs Rate Agreement (NICRA) shall be subject to a maximum allowable indirect rate of 10% of Modified Total Direct Costs. Modified Total Direct Costs include all salaries and wages, applicable fringe benefits, materials and supplies, services, travel, and up to the first $25,000 of each lower-tier subaward and subcontract. Modified Total Direct Costs exclude equipment, capital expenditures, charges for patient care, rental costs, tuition remission, scholarships and fellowships, participant support costs and the portion of each lower-tier subaward and subcontract in excess of $25,000.
F. The NCHRP is a practical, applied research program that produces implementable products addressing problems faced by transportation practitioners and managers. The benefits of NCHRP research are realized only when the results are implemented in state DOTs and other agencies. Implementation of the research product must be considered throughout the process, from problem statement development to research contract and beyond completion of the research. Item 4(c), "Anticipated Research Results," must include the following: (a) the "product" expected from the research, (b) the audience or "market" for this product, (c) a realistic assessment of impediments to successful implementation, and (d) the institutions and individuals who might take leadership in deploying the research product. The project panel will develop and maintain an implementation plan throughout the life of the project. The research team will be expected to provide input to an implementation team consisting of panel members, AASHTO committee members, the NCHRP Implementation Coordinator, and others in order to meet the goals of NCHRP Active Implementation: Moving Research into Practice, available at http://onlinepubs.trb.org/onlinepubs/nchrp/docs/NCHRP_ActiveImplementation.pdf.
G. Item 5 in the proposal, "Qualifications of the Research Team," must include a section labeled "Disclosure." Information relevant to the NCHRP's need to ensure objectivity and to be aware of possible sources of significant financial or organizational conflict of interest in conducting the research must be presented in this section of the proposal. For example, under certain conditions, ownership of the proposing agency, other organizational relationships, or proprietary rights and interests could be perceived as jeopardizing an objective approach to the research effort, and proposers are asked to disclose any such circumstances and to explain how they will be accounted for in this study. If there are no issues related to objectivity, this should be stated.
H. Proposals are evaluated by the NCHRP staff and project panels consisting of individuals collectively very knowledgeable in the problem area. Selection of an agency is made by the project panel considering the following factors: (1) the proposer's demonstrated understanding of the problem; (2) the merit of the proposed research approach and experiment design; (3) the experience, qualifications, and objectivity of the research team in the same or closely related problem area; (4) the plan for ensuring application of results; (5) the proposer's plan for participation by Disadvantaged Business Enterprises--small firms owned and controlled by minorities or women; and (6) the adequacy of the facilities.
Note: The proposer's plan for participation by Disadvantaged Business Enterprises should be incorporated in Item 12 of the proposal.
I. Copyrights - All data, written materials, computer software, graphic and photographic images, and other information prepared under the contract and the copyrights therein shall be owned by the National Academies of Sciences, Engineering, and Medicine. The contractor and subcontractors will be able to publish this material for non-commercial purposes, for internal use, or to further academic research or studies with permission from TRB Cooperative Research Programs. The contractor and subcontractors will not be allowed to sell the project material without prior approval by the National Academies of Sciences, Engineering, and Medicine. By signing a contract with the National Academy of Sciences, contractors accept legal responsibility for any copyright infringement that may exist in work done for TRB. Contractors are therefore responsible for obtaining all necessary permissions for use of copyrighted material in TRB's Cooperative Research Programs publications. For guidance on TRB's policies on using copyrighted material please consult Section 5.4, "Use of Copyrighted Material," in the Procedural Manual for Contractors.