Minnesota Department of Transportation

511 Travel Info

Road Research

NRRA Rigid Team Project

Concrete Overlay Test Section Repairs Utilizing PEM and Diamond Grinding

Status: Active

Objectives

Thin (undoweled) concrete overlays, on concrete or asphalt, develop cracked panels and transverse joint faulting when subject to heavy truck loadings. The primary objective of this research is to diamond grind existing thin concrete overlay test sections at MnROAD, along with a roadway segment in the local county network, that are in the early stages of developing joint faulting, to establish how long the improved ride quality will take to reach the pre-ground levels. Within the MnROAD test cells mentioned above, repairs necessary to keep them in service for an estimated 5 more years will be carried out prior to the grinding, utilizing performance engineered mixtures and associated test methods during installation.

This research will evaluate the feasibility of using PEM materials and test methods for concrete repairs, and the longevity of improved ride quality of thin concrete overlays after diamond grinding. This will be done by performing repairs and diamond grinding two existing COA and 4 existing COC test cells at MnROAD, and then monitoring their performance over a minimum 3-year period. Test cell cross-sections and a table of individual repair areas appears below. Data collected during the evaluation period will include: visual distress surveys, joint opening and fault measurements, joint load transfer performance (Falling Weight Deflectometer data), ride quality profiling, ultrasonic tomography (MIRA), curling and warping measurements, and extracted cores. Using this and other available information (data from previously repaired thin concrete overlay cells at MnROAD) the following items are expected to be addressed to achieve the project objectives over the evaluation period:

  1. Identification of the factors to be considered when designing PEM mixtures for concrete pavement repairs.
  2. Identifying applicable PEM test methods to be performed during paving and acceptance after hardening.
  3. Development of guidelines for successfully producing and placing these materials in the field.
  4. Development of guidelines for when to consider diamond grinding a thin concrete overlay.

Determination of the time for ride quality to return to pre-repair/grind levels.

Tasks

Task 1: Literature Review

In this task, the project team will perform a thorough search and detailed review of literature on the use of PEM materials and testing in concrete pavement repairs, as well as ride quality improvement longevity following diamond grinding. The literature review will focus specifically on how the topics in this study are related to thin concrete pavements and overlays. This information will be compiled into a technical memorandum delivered to MnDOT, along with a technical presentation to TAP.

  • Scheduled Date for Task Final Approval: July 15, 2022
  • Deliverable: Technical Memorandum and Presentation to TAP

Task 2: Construction Testing Analysis

Testing and sample collection be conducted by MnROAD staff and a contracted consultant during and shortly after the construction process. Tests on the fresh and hardened concrete will include (but are not limited to):

  • SAM (Super Air Meter) test
  • 20-30% SCM for oxychloride
  • ASR – R80
  • Shrinkage
  • Resistivity
  • Strength.

The data from construction testing will be processed and entered into the MnROAD database. The hardened concrete testing report (performed by others) will be reviewed, and key findings compared to construction test data. A technical report will be prepared to summarize task findings and submitted to the TAP, along with a summary presentation to the TAP.

  • Scheduled Date for Task Final Approval: April 30, 2023
  • Deliverable: Technical Report and Presentation to TAP

Task 3: Constructability Evaluation

Several factors impact the ability to produce compatible repair materials and successfully diamond grind thin concrete pavements. Preparation of the existing pavement to receive repairs is vitally important. Material consistency and set times can have huge impacts on how well the repairs are placed. The existing pavement needs to be in good enough condition to survive grinding machines and retain enough thickness for structural capacity. Under this task, the project team will evaluate the feasibility of large-scale rehabilitation using PEM materials and tests. The following elements will be evaluated to assess the constructability of PEM concrete repair mixtures: material availability; material handling considerations; issues related to mixing, transporting, placing, and curing; impact of admixtures; ease of making field adjustments; condition of the existing pavement. Information summarized in the comprehensive report documenting the repair and grinding of the MnROAD test cells will be discussed in further depth as it relates to the practicality of using PEM materials prior to diamond grinding. Guidelines will also be provided on how to design, prepare for and execute diamond grinding on thin concrete overlays. A technical report will be prepared to summarize task findings and submitted to the TAP, along with a summary presentation to the TAP.

  • Scheduled Date for Task Final Approval: October 15 , 2023
  • Deliverable: Technical Report and Presentation to TAP

Task 4: 1st Year Performance Update

Under this task, the first-year performance data collected by MnROAD staff on the six concrete overlay test sections will be gathered and summarized. The following data are expected to be reported on: FWD data, seasonal ride quality measurements, distress survey information, MIRA and fault meter measurements, joint opening measurements, curling and warping measurements, and other testing data on extracted cores. Based on the findings, any recommendations for data collection adjustments (i.e., type, frequency) will be communicated to the TAP. A 1st year performance summary report will be provided to the TAP for review and comment. A summary of key findings will be presented to the TAP and/or at NRRA Research Pays Off webinar sessions.

  • Scheduled Date for Task Final Approval: February 15, 2024
  • Deliverable: Technical Report and Presentation to TAP and/or NRRA Research Pays Off Webinar

Task 5: 2nd Year Performance Update

The second-year performance data collected by MnROAD staff on the six concrete overlay test sections will be gathered and summarized. Efforts will mirror that described in Task 4. Comparisons and findings will include data from the 1st and 2nd years of performance monitoring.

  • Scheduled Date for Task Final Approval: February 10, 2025
  • Deliverable: Technical Report and Presentation to TAP and/or NRRA Research Pays Off Webinar

Task 6: 3rd Year Performance Update

The third-year performance data collected by MnROAD staff on the six concrete overlay test sections will be gathered and summarized. Efforts will mirror that described in Task 4. Comparisons and findings will include data from the 1st, 2nd, and 3rd years of performance monitoring.

  • Scheduled Date for Task Final Approval: February 10, 2026
  • Deliverable: Technical Report and Presentation to TAP and/or NRRA Research Pays Off Webinar

Task 7: Determination of efficacy of diamond grinding to mitigate joint faulting in thin concrete overlays

The primary goal of this task is to determine whether diamond grinding of the test cells was sufficient to mitigate the redevelopment of joint faulting. Available fault data will be analyzed and summarized in a technical report. MnROAD performance will be compared to other diamond ground concrete overlay test sites in Minnesota.

  • Scheduled Date for Task Final Approval: May 15, 2026
  • Deliverable: Technical Report and Presentation to TAP

Task 8: Final Technical Review and Revisions of Final Report, and Tech Brief

Description: The research team will prepare a draft final research report and technical brief document (to aid in implementation) that provides a project overview, data, findings, and conclusions. At this time, the report is envisioned to include the following sections:

  • Chapter 1. Introduction, Purpose, and Scope.
  • Chapter 2. Construction Test Results Summary.
  • Chapter 3. Constructability Evaluation.
  • Chapter 4. Performance Comparison and Findings.
  • Chapter 5. Efficacy of diamond grinding to mitigate joint faulting in thin concrete overlays.
  • Chapter 6. Findings and Conclusions.
  • Appendices: Literature Review Summary, Project Data Summaries, etc.

The draft final report and technical brief document will be provided to the TAP 2 months in advance of completing this task. After the draft report is submitted, a TAP meeting will be scheduled to review the contents of the report.

  • Scheduled Date for Final Approval: August 14, 2026
  • Deliverables: A revised document that is technically complete and approved by the TL for publication, Presentation to TAP, and/or NRRA Research Pays Off Webinar

Task 9: Editorial Review and Publication of Final Report and Tech Brief

During this task, the PI will work directly with MnDOT’s contract editors to address any editorial comments and finalize the document or product in a timely manner. The contract editors will ensure the product meets MnDOT’s publication standards and accessibility guidelines (WCAG-compliant).

  • Scheduled End Date: September 30, 2026
  • Deliverables: Final publishable document(s) that meets MnDOT’s publication guidelines and standards

Project team

Email the Project Team
Principal Investigator:
Tom Burnham, Senior Road Research Engineer, MnDOT, tom.burnham@state.mn.us
Co-PI: Michael Wallace, Concrete Research Scientist, MnDOT, Michael.Wallace@state.mn.us
Technical Liaison: Tom Nordstrom, MnDOT, tom.nordstrom@state.mn.us
Project Technical Advisory Panel (TAP): Contact us to join this TAP

  • Gordy Bruhn, Minnesota DOT
  • John Donahue, Missouri DOT
  • Rob Golish, Minnesota DOT
  • Tyler Hunt, Michigan DOT
  • Phillip Ruffus, Missouri DOT
  • Peter Taylor, Iowa State University
  • Dave Van Deusen, Minnesota DOT

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