BACKGROUND
The formation of longitudinal cracks compromises the structural adequacy and reduces the service life of jointed plain concrete pavement (JPCP). Although longitudinal cracking in JPCP has been widely observed by state transportation agencies, the current version of the AASHTOWare pavement mechanistic-empirical design (PMED) software does not account for this critical distress. Studies indicate that longitudinal cracks can be caused by various factors, ranging from construction issues to specific design features.
Research is needed to understand the causes of this distress pattern better and more accurately predict it to prevent or minimize longitudinal cracking, resulting in safer and longer-lasting pavements.
OBJECTIVE
The objective of this project is to identify the causes of longitudinal cracking in JPCP and develop longitudinal cracking predictive models.
Accomplishment of the project objective will require at least the following tasks.
TASKS
PHASE I – Planning
Task 1. Conduct a literature review to identify previous work and reported issues related to longitudinal cracking in JPCP. The review shall also assess the causes (e.g., design features, construction issues, site conditions) and the extent of longitudinal cracking. It shall include both published and unpublished documentation, databases [e.g., long-term pavement performance (LTPP)], past surveys, existing models, and research from the NCHRP; the Federal Highway Administration; other national, state, and local agencies; and international organizations.
Task 2. Survey state departments of transportation (DOTs) to gather information related to longitudinal cracking and identify potential data sources for inclusion in the analysis. The survey shall also include states that have specifically incorporated the design features identified in Task 1, whether or not they have experienced longitudinal cracking.
Task 3. Identify knowledge gaps related to the project objective based on the review and survey performed in Tasks 1 and 2, respectively. These gaps should be addressed in the final product or the recommended future research, as the budget permits.
Task 4. Prepare the data structure, identify pavement sections, and document all potential data sources to be utilized in the study. These data sources (e.g., LTPP sites, projects conducted by state DOTs, and accelerated pavement testing sites) must be evaluated for their reliability before utilization in the study.
Task 5. Propose the research plan to be executed in Phases II and III based on the needs and data identified in Tasks 1 through 4 to achieve the project objective. At a minimum, the research plan shall include a framework to accomplish the following:
- Identify potential causes and describe the failure mechanisms leading to longitudinal cracking. A minimum of 10 case studies are required to validate these failure mechanisms.
- Develop, calibrate, and validate mechanistic-empirical models that predict longitudinal cracking based on relevant design features. The models shall be compatible with and readily implementable in the latest version of AASHTOWare PMED procedures and software.
- Recommend draft language for consideration by the American Association of State Highway and Transportation Officials (AASHTO) to incorporate the research results in the next update of the Manual of Practice and AASHTOWare PMED (herein called the AASHTO Deliverables).
Task 6. Prepare Interim Report No.1, which documents the research performed in Tasks 1 through 5 and provides an updated work plan for the remainder of the research no later than 8 months after the contract is awarded. The updated plan must describe the process and rationale for the work proposed for Phases II and III.
PHASE II – Execution
Task 7. Execute the work plan based on the approved Interim Report No. 1.
Task 8. Prepare a case study report summarizing the outcomes of the case studies.
Task 9. Prepare a model development report that includes the computational code and predictive model.
Task 10. Prepare a preliminary draft of the AASHTO Deliverables.
Task 11. Present the findings from Tasks 7 through 10 to the AASHTOWare PMED task force and the AASHTO Technical Subcommittee 5d to collect comments for potential revisions to the deliverables.
Task 12. Prepare Interim Report No. 2, which documents the research performed in Tasks 7 through 11 and provides an updated work plan for the remainder of the research no later than 30 months after the contract is awarded. The updated plan must describe the process and rationale for the work proposed for Phase III.
PHASE III – Final Deliverables
Task 13. Revise the case study report, the model development report, and the draft AASHTO Deliverables based on the approved Interim Report No. 2.
Task 14. Prepare a stand-alone technical memorandum titled “Implementation of Research Findings and Products”.
Task 15. Prepare presentation materials, in PowerPoint or other formats, for webinars to facilitate the use and adoption of the AASHTO Deliverables.
Task 16. Submit the final deliverables, including (1) a final report documenting the entire research effort, (2) the AASHTO Deliverables, (3) the Implementation of Research Findings and Products technical memorandum, and (4) the presentation materials.
STATUS: Proposals have been received in response to the RFP. The project panel will meet to select a contractor to perform the work.
