All posts by Micaela Resh

Earth Day 2021

April 22 is Earth Day!

Climate change & the environment is one of five research strategic priorities that guide the work of Minnesota’s transportation research program.

This includes research projects specific to endangered & threatened species, wetland protections, salt use and incursion, congestion impacts on air quality, and the impacts of road construction and maintenance activity on the environment.

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Research Pays Off Webinar Series: Determining Pavement Design Criteria for Recycled Aggregate Base and Large Stone Subbase

The National Road Research Alliance (NRRA) is hosting “Research Pays Off: Determining Pavement Design Criteria for Recycled Aggregate Base and Large Stone Subbase” on April 20 at 10 a.m. CST, presented by Bora Cetin, Ph.D., Michigan State University and Raul Velasquez, Ph.D., P.E., Minnesota Department of Transportation.

The NRRA’s monthly seminar highlights research topics that will make an impact on the work done here in the state of Minnesota and around the country.

Project Summary

Although recycled pavement materials have been used in roadway base layers for many years, a specific design method does not exist that describes how to build roadways with these materials. Many state Departments of Transportation (DOTs) assume recycled base materials behave similar to base layers built with conventional virgin aggregates (VA). There is a similar lack of an existing design methodology for pavement systems built with a large stone subbase (LSSB).

The proposed project has three main goals. The first goal of the project is to determine the field and laboratory performance of materials and test sections built with recycled aggregate bases (RAB) including recycled concrete aggregate (RCA), recycled asphalt pavement (RAP), and mixtures of these materials with VA. In addition, similar analyses will be conducted for the test sections built with 18 inches thick LSSB with different compaction methods (1-lift and 2-lift), and those 9 inches thick LSSB built with geogrids and geotextiles. To accomplish this goal, the research team will evaluate both the geomechanical and environmental properties of these pavement systems. It should be noted that the LSSB sections have only one type of aggregate base and the multiple recycled aggregate base sections do not have LSSB indicating that experiments for each different design methods are separate. The second goal of the project is to develop a method to estimate the stiffness and permeability of RAB and LSSB designs. This goal will be achieved by establishing correlations between common laboratory test data and both laboratory and field modulus and permeability values. The third goal is to prepare a pavement design and construction specification for roadways built with RAB and LSSB designs. This goal will be accomplished via a summary of the results of all tasks, taking into account the performance, cost benefits, and life cycle costs of these systems. The outcome of this research will optimize the use of recycled materials and LSSB designs, while maintaining pavement quality, resulting in cost savings and conservation of natural resources.

Visit the MnROAD website for webinar connection information.

Improving Winter Maintenance: Pilot Testing New Snowplow Technologies

[Infographic] Testing Snowplow Technologies: Slurry Spreader (target direction of salt, reduce salt use, reduce corrosion on trucks), Two-Way Reversible Plow (located on side of plow, providing more mobility in plowing and directing snow), Underbody Scraper (located under plow, clears compacted snow and ice from roads), True-Float Wind (mounted on front or side of plow, providing more mobility in plowing and directing snow)

Every winter, MnDOT ensures Minnesotans can travel safely by plowing more than 30,000 lane miles with approximately 800 snowplows.

In a new research implementation project jointly funded by the Office of Research & Innovation and Office of Maintenance, MnDOT is pilot testing five new pieces of snowplow equipment: two slurry spreaders (one from Henke, one from Swenson), a two-way reversible plow, an underbody scraper and a true-float wing (all from Henke).

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New Project: Cost/Benefit Analysis of Fuel Efficient Speed Control Using Signal Phasing and Timing Data

Due to rising fuel costs and environmental impact, consumers are increasingly aware of fuel efficiency (MPG) in the vehicles they purchase, which is reflected in increasing hybrid and electric vehicle sales. A major source of fuel consumption is acceleration and deceleration cycles caused by stopping at red lights—acceleration from a full stop requires significant power.

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New Project: Have Minnesota’s Warmer Winters Increased the Number of Freeze Thaw Cycles?

Minnesota is experiencing warmer winters and an increase in freeze-thaw events may negatively impact pavement systems. However, the impacts of these recent climate changes on freeze-thaw cycles have not been well studied.

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New Project: Taconite as a Lower Cost Alternative High Friction Surface Treatment for Low-Volume Roads in Minnesota

A northern Minnesota mining byproduct could provide a more affordable option for a highly effective, but expensive pavement safety treatment called High Friction Surface Treatment (HFST), and help expand its usage across the state.

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New Project: The Impact of Deferred Maintenance in Minnesota

Expenditures for maintenance are not keeping pace with the needs of the local transportation system. When local governments face fiscal stress, planned maintenance gets postponed to make funding available for other purposes. As deferred maintenance grows, the work and investments needed to bring an asset into a good condition grow too.

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