Category Archives: research

General research posts.

Continuous Moisture Measurement During Pavement Foundation Construction

Accurate and timely moisture measurement of earthwork during compaction of foundation layers is crucial to proper construction and long-term durability of the pavement structures. Since the traditional methods for measuring moisture are point specific, expensive and/or time consuming. None of the existing methods have been able to deliver real-time, continuous moisture measurements that would aid engineers in delivering more durable pavement structures.

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COVID-19 pandemic substantially changed commuting patterns, job access

Reprinted from CTS News, October 9, 2023

Patterns of movement in cities, especially office job commutes, were substantially altered in 2021 by telework, economic change, and other responses to COVID-19, according to new research from the Accessibility Observatory at the University of Minnesota. While the immediate effects of these behavioral changes, such as reduced congestion and lower transit ridership, have been well documented, new data reveals deeper impacts that differ by the three modes studied: auto, transit, and biking.

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Bio-Material Maintenance Treatments

Aging pavement infrastructure and the deterioration of pavement surfaces over time remain an ongoing challenge in meeting roadway user expectations. Preventive pavement preservation treatments that are applied on sound, structured-condition pavements can extend the pavements’ functional service life and reduce future maintenance costs. Fog seals are one of these treatments. Fog seals are applied by spraying a thin layer of emulsion onto the pavement to slow or in some cases reverse the damage caused by oxidative aging. Asphalt emulsions are the most common material used in fog seals. Rejuvenators are usually added to the formulation to lower its viscosity and possibly even rejuvenate the surface of the existing aged pavement.

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Sensor and Drone Technologies Help Maintain Minnesota’s Aging Bridge Infrastructure

Reprinted from Catalyst, September 9, 2023

As bridge infrastructure in Minnesota and across the country ages, maintaining and preserving the existing bridge network becomes increasingly important—and increasingly challenging. In Minnesota alone, 25 percent of bridge-deck area is more than 50 years old, and the number of bridges rated in “fair” condition has recently overtaken the number rated in “good” condition.

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Effect of Low and Moderate Recycled Concrete Aggregate Replacement Levels on Concrete Properties

As the demand for aggregate in construction increases, recycling concrete waste as aggregate has been recognized as an environmentally sustainable solution with potential cost savings. It would allow recycling of construction and demolition waste and reduce some of the need to quarry and haul virgin aggregate. However, the use of recycled concrete aggregate (RCA) has been limited by concerns over its quality and performance, and by lack of uniform specifications as to what kind and how much of the aggregate to use in pavement construction. Studies and on-the-ground experience have shown that high levels of RCA reduce the durability of pavements. The effects of lower replacement levels have not been well documented, however.

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Connecting smart vehicles with traffic signals could reduce fuel use

Originally published in Catalyst, July 18, 2022.

Green means go and yellow means go faster—so goes a wry take on driver behavior at traffic signals. But it’s not just travel time that increases when you brake for a red: Fuel consumption does, too. Could transmitting signal data to connected vehicles (CVs) reduce stop-and-go cycles and fuel use? U of M researchers say yes.

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Researchers Identify Freight Data Sources, Create Guidance to Aid Infrastructure Planning

The goods that continuously move through Minnesota by road, rail, air, water, and pipelines drive the state’s economy, making efficient freight transit—and excellent freight infrastructure—a high priority for the Minnesota Department of Transportation (MnDOT).

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Preparing for the Future of CAVs: Cybersecurity, Winter Weather Research

Connected and automated vehicles (CAVs) hold promise for improving transportation operations—but could also provide pathways for “malicious actors” to compromise vehicle security, said Rafael Stern, a U of M assistant professor, in a recent CTS webinar.

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Strategies improve pollinator roadside habitat, reduce costs

First published in Catalyst, May 22, 2023.

Transportation agencies revegetate roadsides after construction projects to provide road stability, stormwater filtration, and visual appeal. Revegetation is also a good opportunity to create pollinator-friendly habitat. However, planting and maintaining ditches can be expensive, funds for such projects are usually limited, and there isn’t much data on which methods actually work.

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