Minnesota Department of Transportation

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Road Research

NRRA Preventive Maintenance and Flexible Teams

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MnROAD | NRRA | Structure & Teams | Preventive Maintenance Team

Materials-Based Methods to Improve Rumble Strip Durability

Status: In development


The impact of VRAM and RPE on CLRS durability will be investigated during this project. The following project objectives are identified:

  • Perform a literature and agency review of CLRS specifications, construction methods, and durability studies to identify relevant modifications to project scope and work plan;
  • Document “as-constructed” durability effects of CLRS using field cores of newly constructed asphalt pavement sections relative to control (no rumble strip) areas;
  • Evaluate the effects of VRAM on rumble strip durability when used as a pre-construction treatment;
  • Evaluate the effects of RPE on rumble strip durability when used as a post-construction treatment;
  • Document the effects of the above-mentioned materials on rumble strip functionality as a safety tool;
  • Produce “best-practice” guidelines for use of supplementary materials that mitigate the potentially detrimental effects of CLRS on pavement durability.

To accomplish the stated objectives, this project will leverage three new construction projects in 2023. The projects are two-lane Wisconsin County Trunk Highways that offer reasonable size and scope to accommodate the research needs while minimizing impact to the respective County Highway Agencies (CHA). Three projects have been identified to capture reasonable differences in mix design materials and contractor paving methods. Letters of cooperation from each respective CHA have been secured and are attached to this proposal as Exhibit A. Each of the three field projects are expected to contain, at a minimum, control sections without rumble strips, rumble strips with no treatment, use of VRAM pre-construction, and use of RPE post-construction.


Task 1: Review of literature and agency specification

This task will require a literature search, consultation with industry, and an agency specification review. Prior work by the research team demonstrated that materials & methods to improve longitudinal joint performance can be divided into three categories: Construction Methods, Materials During or “Pre-Construction”, Materials Following Construction. Construction methods include joint construction (butt vs. notched wedge) and rolling practice, among others. Construction Materials (such as VRAM and RPE) can be used independent of Construction Method and are therefore the focus of this study. Other materials may be included based on the results of this task.

An additional focus of Task 1 is to identify relevant CLRS specifications based primarily on NCHRP Report 641 and more recent trends; an example is the sinusoidal rumble strip. Efforts will be made to include more than one CLRS geometry in the project, with final decision dictated by Task 1 findings and Technical Advisory Panel (TAP) direction.

Functionality of CLRS will be measured using wayside traffic noise monitoring and tire-pavement sound intensity measurement methods, congruent with NCHRP work. A contractor familiar with the means to perform these measurements has been contacted to confirm availability of testing and consultation prior to this proposal (https://illingworthrodkin.com/).

  • Deliverable: Memo report

Task 2: Finalize work plan

Three CHAs have submitted letters of cooperation for this research project. These CHAs have selected a paving project in 2023 that the research team can contract the installation of CLRS, obtain field cores, and measure rumble strip functionality. Based on the size and scope of the selected project, it is anticipated the following sections will be constructed. Note that VRAM and RPE materials and installation will be donated to the project as a cost-share item.

  • Control: Section without rumble strips, or section prior to installation of the rumble strips;
  • VRAM: Application following MnDOT Provisional Specification 2331;
  • RPE: Applied to the according to InDOT provisional specification 401-R-736 guidance;
  • VRAM + RPE: If project logistics allow, a combination of treatments as described above will be used.

Ten six-inch diameter road cores will be taken directly on the centerline joint per section to provide samples for laboratory evaluation (See Task 4). Loose plant-produced mixture will be sampled to conduct crack resistance testing on the surface mixture at low and intermediate temperature.

  • Deliverable: Final work plan

Task 3: Execute and document field projects

Design & construction of the projects will follow respective CHA process. Any relevant information or data in this regard will be documented. Nuclear density measurements at the mainline and centerline with companion cores will be taken according to WisDOT Item 460.0105.S for non-VRAM and RPE (pre-application) sections. The cores and associated plant produced mixtures described in Task 2 will also be collected at this time.

CLRS will be installed with project funding utilizing local contractors following regional specification. At least one contractor meeting this description has been identified at the time of this proposal (https://surfprep.com/). Measurement of CLRS functionality through sound measurement will measure impact of selected materials on CLRS function and evaluate whether the treatments improve nuisance noise. A contractor familiar national-scale work on rumble strip performance has been consulted during the drafting of this proposal (https://illingworthrodkin.com/). This testing will also be completed using project funding. Although long-term performance monitoring of field sections is beyond the scope of this proposal, the work plan is structured to allow for follow up/extension monitoring studies.

  • Deliverable: Construction process data will be detailed by onsite technicians and summarized as part of Task 3. All relevant data will be housed in Excel-based databases but summarized in reports and update slide decks for the TOC.

Task 4: Laboratory evaluation of road cores and mixture samples

Road cores and associated samples will be delivered to the Heritage Research Group laboratory for testing. The following testing protocol is proposed for the road cores. Note that all proposed testing has been demonstrated in prior literature to be relevant to the stated objectives of this project, minimizing experimental development effort. Since the primary distress associated with longitudinal joints is durability (cracking), measurement of rutting resistance or high temperature stiffness is not included in this study. Road cores will be randomly divided into two groupings, with one grouping being tested immediately upon receipt and processing and the second grouping undergoing long term aging according to AASHTO R30. Both groups will ultimately receive the same testing protocol. Mixture samples collected during the project can be used as calibration of the respective field core measurements since volumetrics can be more easily controlled.

  • Deliverable: The data generated in this task will be first housed in an Excel based database, which in turn will be summarized in the update presentations and final report to the TOC.

Task 5: Reporting of findings and best-practice guidelines

This task will include submission of the project close-out presentation, final report, and associated databases. As part of the final report, direct best-practice guidelines will be summarized based on the findings of this project. Any associated material specifications or provisions references will either be included or clearly linked to the final documentation. The intention of this project is to produce results that are as “practice-ready” as possible. The makeup of the research team is uniquely qualified to deliver on this objective.

  • Deliverables: Final report

Project team

Email the Project Team
Principal Investigator(s): Dan Swiertz, PE; Asphalt Materials, Inc., dswiertz@bitumixsolutions.com; Katie DeCarlo, PhD; Heritage Research Group, kdecarlo@hrglab.com; Signe Reichelt, PE; Behnke Materials Engineering, smreichelt@behnkematerialsengineering.com
Technical Liaison: Tyler Hunt, Michigan DOT, HuntT2@michigan.gov
Project Technical Advisory Panel (TAP): Contact us to join this TAP

  • Ashley Buss, Iowa DOT
  • Doug Carlson, Liberty Tire
  • Stephen Cooper, FHWA
  • Ian Gilhooly, Illinois DOT
  • Rob Green, Michigan DOT
  • Josh Heck, Montana DOT
  • Tyler Hunt, Michigan DOT (TL)
  • Joseph Podolsky, MnDOT
  • Phillip Ruffus, Missouri DOT
  • Joel Ulring, MnDOT
  • Michael Vrtis, MnDOT

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