Continued Monitoring of Original I-94 Westbound Asphalt Overlay Sections and Use of Cracking and Performance Data MRCC Project

MnROAD | NRRA | Structure & Teams | Flexible Team

Status: In development

Objective

Asphalt overlays are by far the most used rehabilitation alternative for asphalt and Portland Cement Concrete (PCC) pavements. Thin and ultra-thin asphalt overlays are also commonly used for maintenance and preservation purposes. Longevity of asphalt overlays is severely limited due to premature cracking and subsequent loss of serviceability from deterioration of pavement in the vicinity of cracks manifesting in increased pavement roughness and continued loss of pavement structural integrity. Unlike conventional asphalt pavement design where properties and structural contributions of subsurface layers can be controlled, asphalt overlays are typically placed on a distressed pavement that has experienced loss of structural, and/or functional capacity. Due to complexities associated with accurate prediction of reflective cracking, many public transportation agencies have reverted to use of policy-based overlay thickness and material selection approaches. Further, pavement engineers have often reverted to use of more economical asphalt mixtures for overlays due to high rates of reflective cracking; with currently available overlay material selection and thickness design tools, use of premium asphalt mixtures have often resulted in poor life cycle costs.

The original I-94 westbound asphalt overlay test cells were constructed as part of the one of the very first NRRA flexible team projects to study focused on rehabilitation of concrete pavements using asphalt overlays and to assess different volumetric approaches of designing asphalt mixtures and to track their field density evolution over time. This study is also often referred to as the NRRA reflective cracking phase-I study. The twelve pavement test sections from this effort were constructed in 2017. The cracking and roughness data from the first three years of service from these sections were utilized in the development of the NRRA asphalt overlay material and thickness selection tool. One of the challenges that was faced by the research team in that study was the lack of distinction in the roughness between different test sections. This was not completely unexpected, while sections exhibited varying reflective cracking rates, the cracks did not have sufficient time to deteriorate to yield serviceability differences. With the current MnROAD Reflective Cracking Challenge (MRCC) research underway, which will develop and expand the phase-I implementation products by including performances of asphalt overlays on flexible pavements, there is a very strong case to continue performance evaluation on the phase-I test sections. The materials from phase-I are already very well characterized and the performance prediction models have already been developed. By continued monitoring of the test sections on the original I-94 westbound, the past NRRA research and the current MRCC efforts will be substantially leveraged, and the final outcomes of MRCC effort will be developed using larger performance datasets. The main objective of the proposed effort is to provide necessary resources to the researchers to include the performance and other instrumentation data (such as, temperature) from original I-94 westbound reflective cracking study sections with the ongoing efforts of the MRCC study.

Tasks

Task 1: Mechanistic modelling of overlays

Mechanistic evaluations of the overlay test sections using the AASHTOWare PavementMETM, FlexPAVETM, IlliTC, Texas M-E Asphalt Overlay software (TxACOL), and high-fidelity finite element simulation using extrinsic cohesive zone models and thermo-viscoelastic asphalt mixture response (CZFEM) in the ABAQUS software package will be considered. During this task, a comparative evaluation of various mechanistic models will be conducted to assess their ability to predict the reflective cracking performance of the original I-94 westbound sections. The model(s) that most reliably predict overlay performance will be selected for use in the parametric evaluations. As a tangible benefit, this effort will also inform NRRA agencies of mechanistic overlay performance models that can be considered for overlay design purposes by their respective pavement design units. At a minimum, the parametric evaluations will include variations of overlay thickness, overlay mixture types, underling pavement conditions and structure, traffic levels and climate (location). A statistical design of experiments approach will be adopted to develop a partial factorial parametric evaluation study. The outcomes of parametric evaluations will be used to populate an overlay performance database for use in subsequent tasks. At the beginning of this task, the research team will work closely with the MnROAD staff to obtain the instrumentation and overlay performance data that has been collected since end of the phase-I Sustainable Asphalt Overlays for Rehabilitation of Pavements research. The research team will also work with MnROAD staff to establish the data collection intervals and data transfer protocols for the duration of the study.

Deliverable: Data collection plan and summary of data obtained from MnROAD staff and a comprehensive task report with results of mechanistic modeling, comparisons of model predictions with original I-94 westbound pavement section performances and parametric analysis results.

Task 2: Life cycle assessment

LCA will be conducted for the original I-94 westbound test sections. Data sources used for the Life Cycle Inventory (LCI) phase of the LCA will be those that are open sourced, such as those found in Federal LCA Commons. The research team will leverage a combination of OpenLCA and FHWA’s new LCA Pave tool to perform the LCA. This will provide NRRA members with a case study of how to apply the new, user-friendly tool. Further, data that is generated will be made available through LCA commons as appropriate for future use.

Deliverable: Task report with detailed discussion of LCA on study sections as well as summary of LCI and LCA plug-ins for the decision tool.

Task 3: Asphalt overlay life and performance curve prediction tool

The cracking and serviceability data from original I-94 westbound overlay sections will be processed in this task along with data generated through the parametric evaluations of Task 1. All statistical analyses as well as artificial intelligence-based prediction model development efforts that are planned for MRCC effort will also be conducted for datasets from the proposed efforts.

Deliverable: Task report detailing life and performance curve model development data and corresponding analyses. Life and performance curve model will also be delivered for TAP review and feedback.

Task 4: Decision tool development

The decision tool for selecting appropriate asphalt overlay mixtures and thicknesses based on known parameters (such as existing pavement condition, anticipated traffic levels, planned maintenance/preservation strategies etc.) will be the most important outcomes of the proposed study. This task will incorporate the outcomes from tasks 1, 2 and 3 to develop a user-friendly tool that is capable of providing users with the life cycle costs, life and performance curves, and global warming potentials for different overlay materials and structures. This task will ensure that performance data from original I-94 westbound overlay sections (and those from mechanistic model parametric evaluations) is fully integrated with the MRCC decision tool.

Deliverable: Task report summarizing the decision tool development, detailed user guide for use of decision tool as well as a recorded video guide/demonstration of tool. And its features, decision tool will be submitted to TAP during this task for review and feedback and it will be revised on the feedback.

Task 5: Draft final report

It would be the intent of the research team to combine the final report originating from this effort with the final report of MRCC effort. However, for administrative purposes, the draft final report and final report tasks are separately proposed at this point in time. A comprehensive final report will be developed that will include efforts from tasks 1-4 as well as overlay life and performance curve model, and the overlay decision tool. In addition to the comprehensive report, all electronic tools and databases developed during the project will also be submitted.

Deliverable: Comprehensive final report and, all applications and databases developed during project.

Task 6: Editorial review and final report publication

Conduct editorial review on final report for publication.

Deliverable: Final report and any other publishable deliverables that meets MnDOT’s Editorial Guidelines and Standards

Project team

Email the Project Team
Principal Investigator(s): Eshan V. Dave, Ph.D., Department of Civil and Environmental Engineering, University of New Hampshire, eshan.dave@unh.edu
Technical Liaison: Ashley Buss, Iowa DOT, Ashley.Buss@iowadot.us
Project Technical Advisory Panel (TAP): Contact us to join this TAP

Ashley Buss, Iowa DOT (TL)
Shongtao Dai, MnDOT
Rouzbeh Ghabchi, SDSU
Elie Hajj, University of Nevada - Reno
Brian Hill, Illinois DOT
Mohammad Sabouri, Braun Intertec
Michael Vrtis, MnDOT
Charles Wienrank, Illinois DOT

Related materials

Initial idea proposal (PDF), 5/5/2023