Service Life Enhancement of Substrates Overlaid with Thin Overlays (UTWBC, Chip Seals & Microsurfacing) for each state
Project Start Date: May 10, 2019
Project End Date: May 2020
Thin overlays have been popularized as preventive maintenance recently as they are cost-effective and proven to extend the life of pavement. However, the expected service life of these fixes is dependent on various factors such as the condition of substrates and the maintenance window. This project focuses on conventional non-structural overlays, which include chip seals, ultra-thin bonded wearing course (UTBWC), and micro-surfacing. These non-structural overlays are generally placed over flexible substrates, which include flexible pavements that have received bituminous interventions on bituminous upper layer (BOB), flexible pavements that have received bituminous interventions on concrete layer (BOC), and flexible pavements that have not received any intervention since constructed on aggregate base (BAB). The objective of this project is to determine the service lives for the three non-structural overlays and deduce the service life enhancements that these non-structural overlays contribute to the identified flexible substrates on which the overlays were placed based on the pavement management data from the National Road Research Alliance (NRRA) member states.
The goal of this project is to utilize applicable analytic methodology to evaluate the service life enhancement of flexible substrates overlaid with thin overlays, which include ultra-thin bonded wearing course (UTBWC), chip seals, and micro-surfacing. First, the PI will coordinate with the NRRA member states, which include California, Illinois, Iowa, Michigan, Minnesota, Missouri, North Dakota, and Wisconsin to collect the pavement management data on all three thin overlay interventions in the specified pavement types (BOB, BOC, and BAB). The PI will collaborate closely with the NRRA Technical Liaison throughout the analysis process to determine the extensions of life for each type of fixes, the failure-modes, and the optimum timing of intervention. This could include developing multiple performance curves, using tenable analytical methods to evaluate and quantify data, and multiple meetings with the NRRA technical liaisons to discuss findings and recommendations. Final deliverables will be a publishable report that meets MnDOT’s editorial guidelines and standards.
Task 1C: Data collection and performance analysis on the conventional non-structural overlays
The PI will gather pavement management data from the NRRA member states identified as California, Illinois, Iowa, Michigan, Minnesota, Missouri, North Dakota, and Wisconsin for all three thin overlay interventions in the three pavement types specified. This data collection effort will be followed by creating and evaluating performance curves of all the overlays on flexible substrates, which comprises of nine case scenarios. The PI will provide an analysis on possible benefits of this research project if conclusions can be successfully drawn from the data.
- Scheduled Date for Task Final Approval: July 31, 2019
- Deliverable: Assembled spreadsheet data and plots and meetings with the NRRA Technical Liaison to discuss findings.
Task 2C: Analysis on remaining service life and reliability analysis
The PI will develop performance curves on remaining service life (RSL) for each case scenario. According to MnDOT, RSL is defined as zero when the ride quality index (RQI) falls on 2.5 or below. The PI will also perform reliability analysis and solve the three-parameter Weibull equation to determine the characteristics of life extensions, failure modes, and threshold time to reach failure. Performance curves will be evaluated to obtain the spikes, optimum timeframe to rehabilitation, and RSL. Any characteristic on improvement trends will be identify and quantify.
- Scheduled Date for Task Final Approval: August 31, 2019
- Deliverable: An analysis report summarizing the information compiled under Task 2 and meetings with the NRRA Technical Liaison to discuss findings.
Task 3C: Analysis on added effects and/or benefits of non-structural overlay interventions
The PI will analyze performance curves and identify common intervention trends. The PI will also utilize tenable analytical methods to determine and quantify the added effects of non-structural overlay interventions.
- Scheduled Date for Task Final Approval: September 30, 2019
- Deliverable: An analysis report summarizing the information compiled under Task 3 and meetings with the NRRA Technical Liaison to discuss findings.
Task 4C: Compile report, technical advisory panel review, and revisions
The PI will prepare a draft final report, following MnDOT publication guidelines, to document project activities, findings and recommendations. This report will be reviewed by the Technical Advisory Panel (TAP), updated by the PI to incorporate technical comments, and then approved by the Technical Liaison before this task is considered complete. If possible, a TAP meeting will be scheduled to facilitate the discussion of the draft report.
- Scheduled Date for Final Report Approval: October 31, 2019
Task 5C: Editorial review and publication of final report
During this task, the PI will work directly with MnDOT’s contract editors to address editorial comments and finalize the document in a timely manner. The contract editors will publish the report and ensure it meets publication standards. The PI will also present the results in the Research Pays Off webinar.
- Scheduled End Date: October 31, 2019
- Deliverables: Final report that meets MnDOT’s editorial guidelines and standards.
Principal Investigator: Andrea Blanchette, PE, WSB
Co-Investigator: Tom Wood, WSB
Co-investigator: Sheue Torng Lee, WSB
Technical Liaison: Jerry Geib, MnDOT, firstname.lastname@example.org