Tag Archives: MnROAD

Peer Exchange: Pavement researchers face similar issues, financial pressures

Soaring construction costs and a rapidly aging infrastructure will require states to revolutionize how they maintain their roadways — but without each other’s help, they won’t be successful.

That was a key message from pavement researchers last week at a MnDOT-hosted peer exchange event, where pavement experts from around North America shared their ideas and research experiences.

“You’ve got to partner with other states, the FHWA and industry,” said Research Engineer Steve Bower of the Michigan Department of Transportation. “We can’t go it alone anymore.”

Researchers at the event reviewed recent pooled-fund studies conducted at MnROAD, MnDOT’s innovative pavement testing center, to review successful implementation strategies, develop common practices to calculate benefits and help prioritize research topics for MnROAD’s  core 2016 research and reconstruction.

The pavement engineers gathered for the event face similar problems in their home states, as demonstrated by the seven pooled fund projects that were discussed. These included developing a better understanding of pavement damage caused by oversized farm equipment, knowing when to chip seal a roadway, developing a test to predict asphalt cracking , creating a national design method for concrete overlays of asphalt roadways and improvements in diamond grinding of concrete pavements.

MnROAD leading the way

State research departments often lack the time or resources to focus on innovations that could reduce future maintenance costs. If not for Minnesota leading the effort on many of these topics and providing a top-notch research facility, the peer exchange attendees said much of this research just wouldn’t happen.

“We don’t have a closed-loop facility with all these different test sections that MnROAD has; no one does,” said Larry Wiser of the Federal Highway Administration’s Turner-Fairbank Highway Research Center.

Researchers came from Missouri, Maine, Texas, Illinois, Michigan, California, Ontario, Wisconsin, Indiana and Washington for the three-day workshop.
Researchers came from Missouri, Maine, Texas, Illinois, Michigan, California, Ontario, Wisconsin, Indiana and Washington for the three-day workshop.

WisDOT Chief Materials Management Engineer Steven Krebs said the research done at MNROAD on the impact of modern farm implements on pavement was invaluable in drafting new state legislation. WisDOT was able to quantify the amount of damage done to the pavement and use the data to dispute mistruths and  misinformation. The state is now working with counties on possible remedies and weight-limit enforcement techniques.

Whereas Minnesota has taken the lead on studying such issues, it is now asking fellow states to not only participate in future such studies, but to also partner in the operations at MnROAD.  At the peer exchange, the response to this idea — especially from states closest to Minnesota — was positive, despite everyone’s lean budgets.

Peer exchange participants said more effort and funding is needed to implement research findings, which FHWA officials said costs significantly more than the research itself.

Past research also needs to be more accessible and there should be better sharing of information, particularly online, they said.

“This (peer exchange) gave us ideas to take back. Our research budget is getting tighter. It’s nice to be able to say, ‘You do a part of it and we’ll do a part of it,’ ” said California transportation researcher Joe Holland.

Further Resources

2014 Peer Exchange – Presentations

MnROAD 2014 Peer Exchange (photo gallery)

MnROAD is hosting pavement researchers from around North America this week to discuss research conducted at its cold weather pavement testing facility in Albertville, Minnesota.

Participants at the three-day conference (June 10 to 12) are reviewing the findings of recent pooled fund studies, sharing their implementation experience and recommending what projects should be picked for the next round of research.

Bob Orthmeyer from the Federal Highway Administration, said MnROAD was the only facility in the country that could supply several test sections needed for a recent study.
Bob Orthmeyer from the Federal Highway Administration said MnROAD is the only facility in the country that could supply several test sections needed for a recent study.
Graig Gilbertson from MnDOT District 8 listens to one of seven presentations Tuesday on the latest research.
Graig Gilbertson from MnDOT District 8 listens to one of seven presentations Tuesday on how agencies have implemented MnROAD’s second phase of research projects.
Stephen Lee shares the Ontario Ministry of Transportation's experiences during a discussion Tuesday on research implementation.
Stephen Lee shares the Ontario Ministry of Transportation’s experiences during a discussion Tuesday on research implementation.
Steve Bower, a Michigan Department of Transportation Research Engineer, visits with MnROAD researcher Bernard Izevbakhai, right, and others during a break.
Steve Bower, a Michigan Department of Transportation Research Engineer, visits with MnROAD researcher Bernard Izevbakhai, right, and other peers.
Construction engineering professor Joe Mahoney, from the University of Washington, leads a group discussion on improving research efforts at the close of the session Tuesday.
Construction engineering professor Joe Mahoney, from the University of Washington, leads a group discussion on improving research efforts at the close of the session Tuesday.
From left, Dave VanDeusen from MnDOT, LaDonna Rowden from the Illinois Department of Transportation, Magdi Mikhail from the Texas Department of Transportation and Samy Noureldin from the Indiana Department of Transportation. — at Holiday Inn Bloomington I-35W.
From left, Dave VanDeusen from MnDOT, LaDonna Rowden from the Illinois Department of Transportation, Magdi Mikhail from the Texas Department of Transportation and Samy Noureldin from the Indiana Department of Transportation.
Researchers came from Missouri, Maine, Texas, Illinois, Michigan, California, Ontario, Wisconsin, Indiana and Washington for the three-day workshop.
Researchers came from Missouri, Maine, Texas, Illinois, Michigan, California, Ontario, Wisconsin, Indiana and Washington for the three-day workshop.

 

New test could help asphalt pavements survive winter intact

If there was ever a winter that demonstrated what cold weather can do to asphalt pavements, last one was it. But future winters may wreak less havoc on Minnesota roadways, thanks to a new asphalt mixture test in the final stages of evaluation by MnDOT’s Office of Materials and Road Research (OMRR).

Developed through a decade-long multi-state research project, the Disc-shaped Compact Tension (DCT) test evaluates the low-temperature performance of asphalt mixes. (See a video about the project that helped develop the DCT test below.)

For the first time, engineers will be able to predict how well a contractor’s proposed asphalt mix will hold up under harsh Minnesota winters.

“Performance testing is assuring that we’re getting what we’re paying for,” explained MnDOT Research Project Engineer Luke Johanneck.

Low-temperature cracking is the most prevalent form of distress found in asphalt pavements in cold climates. As the temperature drops, the pavement tries to shrink, creating cracks that allow water to seep in and eventually lead to pavement deterioration.

Until now, engineers have typically evaluated the individual components (such as amount of crushed aggregate and asphalt binder grade) and volumetric properties (such as air voids and asphalt content) of an asphalt mix, not how the final product performs in low temperature.

“It’s like baking a cake,” explained MnDOT Bituminous Engineer John Garrity. “Our current system says put in a half-cup of oil, two eggs and cake mix. Rather than just looking just at those individual components, taste the cake to see how good it is.”

Created by researchers at the University of Illinois, the DCT test applies tension to an asphalt mixture sample to determine its thermal fracture resistance. The test was determined to be the best of several methods looked at in another research study, conducted by the University of Minnesota with assistance from neighboring state universities.

The Disc-Shaped Compact Tension Test measures the fracture energy of asphalt  mixture lab or field specimens, which can be used in performance‐type specifications to control various  forms of cracking.
The test measures the fracture energy of asphalt mixture lab or field specimens, which can be used in performance specifications to control various forms of cracking.

The Office of Materials and Road Research is conducting pilot tests to become more familiar with the DCT test and to educate road contractors, who may eventually be required to use the test in Minnesota.

“This is very new to a lot of people that have been in the business for a long time,” Johanneck said.

Last summer, OMRR asked five contractors to submit asphalt mixes for testing. If a mix didn’t pass, the contractor was given suggestions for how to modify their recipe to better resist thermal cracking. This summer, OMRR plans to collect asphalt mixes from around the state to see how they measure up against a set of performance targets that were developed in the pooled fund study.

“We envision this at some point being part of our standard bid specifications,” Garrity said.

Those with a professional interest in the subject might be interested in a new video from MnDOT Research Services & Library (below) that demonstrates how to do the sample preparation for the DCT test.

Research Studies

Current DCT Test Implementation Project (2014) Pooling Our Research: Designing Asphalt Pavements That Resist Cracking at Low Temperatures (March 2013 Technical Summary) Synthesis of Performance Testing of Asphalt Concrete (September 2011) Investigation of Low Temperature Cracking in Asphalt Pavements National Pooled Fund Study 776 (2007 report)

Related Videos

Frost Damage in Pavement: Causes and Cures (full-length) Frost Damage in Pavement: Causes and Cures (short version)

Innovative pavement textures reduce noise, improve fuel economy

What if something as simple as changing the texture of the pavements we drive on could not only increase safety, but also reduce noise pollution and boost our vehicles’ fuel economy?

It’s possible, according to the latest research from MnROAD, the state’s one-of-a-kind pavement research facility. In a new report, investigators detail how quieter pavement textures, such as those applied by grinding grooves into pavements with diamond-coated saw blades (see the photo above), may also reduce rolling resistance — the force that resists a tire as it moves across the pavement’s surface.

The potential benefits to the public are significant. A 10-percent reduction in rolling resistance could reduce the U.S. public’s fuel consumption by 2–3 percent, eliminate up to $12.5 billion in fuel costs each year (as well as cutting carbon emissions). Add on the cost savings from reducing noise pollution (building noise barriers along highways can cost as much as $3 million per mile), and it’s clearly a win-win situation.

In the study, researchers used an innovative line-laser profiler to develop three-dimensional representations of test pavement surface textures. They then investigated the relationship between these surface characteristics and data on rolling resistance that was collected during a 2011 study using a special test trailer developed by researchers in Poland. This year, the same trailer will be used to conduct a second round of rolling resistance measurements at MnROAD.

The research is related to an ongoing pooled-fund study on concrete pavement surface characteristics. The goal is to produce data that will allow MnDOT to identify ideal ranges for surface characteristics that improve pavements’ quietness and ride quality while keeping them safe and durable.

Learn more
Researchers relied on rolling resistance data from a study conducted in 2011 with a test trailer developed by the Technical University of Gdańsk, Poland. This was the first time such measurements were taken in the United States.
Researchers relied on rolling resistance data from a study conducted in 2011 with a test trailer developed by the Technical University of Gdańsk, Poland. This was the first time such measurements were taken in the United States.

MnROAD earns concrete pavement association award

Staff from MnROAD, the Minnesota Department of Transportation’s cold weather road research facility in Albertville, Minn., were presented with the Marlin J. Knutson Award for Technical Achievement by the American Concrete Pavement Association in December.

The award cites the facility’s well-deserved reputation for being a place where both agency and industry ideas are put to the test. This award was presented as a tribute to the agency’s commitment to learning and putting ideas into practice.

The Marlin J. Knutson Award for Technical Achievement is presented to an individual or group who has made significant contributions to advance the development and implementation of technical innovations and best practices in the design and construction of concrete pavements.

(far right) Gerald Voigt, ACPA president and CEO, presented MnDOT with the Marlin J. Knutson Award for Technical Achievement during a ceremony in December. Receiving the award are (from left) Luke Johanneck, Bernard Izevbekhai, Roger Olson, Tom Burnham, Glenn Engstrom, Maureen Jensen and Sue Mulvihill. (Photo courtesy of the ACPA)
(Far right) Gerald Voigt, ACPA president and CEO, presented MnDOT with the Marlin J. Knutson Award for Technical Achievement. Receiving the award are (from left) Luke Johanneck, Bernard Izevbekhai, Roger Olson, Tom Burnham, Glenn Engstrom, Maureen Jensen and Sue Mulvihill. (Photo courtesy of the ACPA)

“MnROAD is helping to make roads last longer, perform better, cost less, construct faster, and have minimal impact on the environment,” said Gerald Voigt, ACPA president and CEO. “It is a model for other agencies to follow.”

MnROAD is a pavement test track initially constructed between 1991-1993. It uses various research materials and pavements and finds ways to make roads last longer, perform better, cost less to build and maintain, be built faster and have minimal impact on the environment. MnROAD consists of two unique road segments located next to Interstate 94.

Staff from the MnROAD facility in Albertville were recognized during the ACPA’s Distinguished Service and Recognition Awards ceremony in December. (Photo by David Gonzalez)
Staff from the MnROAD facility in Albertville were recognized during the ACPA’s Distinguished Service and Recognition Awards ceremony in December. (Photo by David Gonzalez)

This article, authored by Rich Kemp, originally appeared in Newsline, MnDOT’s employee newsletter. 

Geotextile research at MnROAD

Geotextiles are synthetic polymer materials used to improve the performance of roadways. As discussed in this 2011 technical summary, geotextiles facilitate filtration and water drainage, improve the integrity and functioning of base materials, and provide a stable construction platform over soft or wet soils. These improvements can benefit both the cost-efficiency and longevity of pavements.

Geosynthetic materials have been used throughout Minnesota, and can be found in both reconstructed and new roadway projects. The use of geotextiles as a separator layer under concrete overlays, however, has had limited documentation in Minnesota and other cold weather climates. MnROAD‘s recent dedication of several test cells to this purpose will determine the performance of this application of geotextiles, with the goal of improving its applications on other Minnesota roadways.

The new test sections, designated as Cells 140 and 240, consist of a very thin, 3-inch concrete overlay over an existing 7-inch concrete pavement constructed 20 years ago. Some unique features of the design include the use of a fiber-reinforced concrete mix, two different thicknesses of the nonwoven geotextile, and the use of a special type of glue, rather than nails, to fasten it to the existing concrete before paving.

The fabric and fiber used in the concrete mix were supplied through a public-private partnership with Propex Geotextile Systems. The results of this study, along with other unbonded overlays constructed at MnROAD and around the country, will be incorporated into a new national pooled fund project — TPF 5-(269) — led by MnDOT. This project will develop an improved mechanistic design procedure for unbonded overlays.

A second application being demonstrated at MnROAD is the use of a geosynthetic drainage system under several dowel bar baskets in new concrete pavement test section. Minnesota has historically used a dense-graded base layer under concrete pavements to provide a stable foundation and construction platform. However, this material drains very slowly, and traps moisture within the joints, leading eventually to significant distress (See Effect of Drainage on the Performance of Concrete Pavement Joints in Minnesota.) This application will compare the use of the geotextile drainage material placed under both sealed and unsealed joints, as well as a control joint without the drainage material.

Permeable pavements could protect the environment, save taxpayer dollars

KSTP has a nice story today on the Minnesota Department of Transportation’s ongoing research into permeable pavements at the MnROAD research facility. (The video isn’t embeddable on WordPress, but you can find a direct link here.)

Permeable pavements (also known as “porous” or “pervious” pavements) are designed to allow water to pass through roadways and infiltrate directly into the underlying aggregate and soil. Their primary effect is to reduce stormwater runoff, which carries harmful materials from the road’s surface out into waterways. Of course, reducing runoff also mitigates the need for the kinds of costly drainage structures that are normally required to manage stormwater. Permeable pavements also reduce noise and mitigate the potential for hydroplaning, among other documented benefits.

These types of pavements are already used in some areas in Minnesota — mainly in parking lots and city streets — and MnDOT has been studying their potential use for full-depth roadway pavements. As the video indicates, so far the results have been encouraging. (You can read more about MnDOT’s ongoing research on the MnROAD website.)

As a side note, the amount of water these pavements can absorb is quite impressive. Last month, we posted a new Local Road Research Board video on stormwater management. In one scene, a public works crew dumps what appears to be several hundred gallons of water onto a permeable pavement and watch as it disappears almost instantaneously. (Watch the clip here.)

Here are the results of some recent permeable pavement studies here in Minnesota: