In recent years, MnDOT has seen an increase in cracking of low slump overlays. Cracking of overlays allows chlorides to get into the bridge deck which leads to deterioration of the reinforcement and eventual delamination or spalling. This means that the bridge deck needs to be repaired or even replaced before the service life has been reached.
What is a low slump overlay? A low slump overlay is a technique used by DOTs to extend the life of bridge decks. They are typically 2″ thick and designed to provide low permeability.
Geogrid inserted between the layers of asphalt pavement during construction can increase the strength and durability of the finished road. To help engineers decide whether to use geogrids in road construction projects, researchers calculated just how much strength and durability geogrid material can add to an asphalt pavement and integrated the findings into MnDOT’s design software.
In search of enhanced pavement damage detection practices, researchers investigated two innovative additives to asphalt binders: graphite nanoplatelets and taconite concentrates. They also examined the ability of microwave energy to restore subsurface cracking.
Roadside infiltration facilities like wet ponds and swales have been used for more than 30 years to filter roadway contaminants from stormwater runoff, but they have a high rate of failure due to inaccurate determination of soil infiltration rates.
Researchers investigated pavement segments within MnDOT’s pavement management system that had received a poor ride quality level rating for more than five years. Their investigations showed that for most segments, the true pavement conditions differed from listed ratings due to the pavement segments’ unique characteristics.
To help make roads as safe as possible in winter, MnDOT uses dynamic message signs (DMS) to display weather advisories to drivers. Using DMS to display real-time road condition information could further enhance safety by potentially resulting in reduced driving speeds and safer following distances. Roadside pavement sensors can provide real-time road condition data for these warning messages, alerting drivers to conditions ahead.
The COVID-19 pandemic resulted in fewer drivers on Minnesota’s roads in 2020 than in the previous year. Emptier roadways seem like they should be safer, but many states measured increases in speeding. For example, California issued twice as many speeding tickets, Iowa reported a 65% increase in driving 25 mph or more over the speed limit, and Ohio experienced the highest number of traffic fatalities since 2007. Clearly, some drivers were taking advantage of empty streets to speed. The pandemic also strained police forces, resulting in less enforcement.
In this follow-up study, researchers checked the effectiveness of revised specifications for tightening anchor rods on sign and signal support poles. The revised specifications will ensure correct tightening procedures, which will result in better installations and maintenance.
This article was originally published in Catalyst, November 2021.
With the improvements made to their lane-departure warning system, U of M researchers are one step closer to preventing highway crashes and deaths. In a recent project, the research team enhanced its lane-departure warning system, which uses standard GPS data rather than expensive cameras or maps—moving toward an affordable, market-ready product to warn drivers about dangerous lane drift due to drowsiness or inattention.
This article was originally published in Catalyst, November 2021.
How does a transitway affect automobile traffic on nearby roadways? What factors influence which park-and-ride facilities people choose? These two questions were the focus of a recent two-part project by U of M researchers.
Crossroads 