Tag Archives: Local Road Research Board

County GIS Maps Help Road Departments Anticipate Slope Failure

In a recently completed pilot study, researchers developed maps for two Minnesota counties that rank the failure potential of every slope using a geographic information system (GIS)-based model.

“GIS mapping has been applied to very small watersheds. The two counties in this study are huge areas in comparison. We used a physics-based approach that shows engineers where slope failure is likely to occur,” said Omid Mohseni, Senior Water Resources Manager, Barr Engineering Company.

What Was Our Goal?

The goal of this study was to determine if slope failure models could be developed to help counties anticipate where failures may occur. Researchers used publicly available data, research findings and geotechnical theory to develop failure models that could then be mapped with GIS in two topographically dissimilar Minnesota counties. These maps would identify slopes susceptible to failure so that county highway departments could develop preventive strategies for protecting roadways from potential  lope failure or prepare appropriate failure response plans.

What Did We Do?

Researchers began with a literature review of studies about the causes of slope failure, predictive approaches and mapping. They were particularly interested in research related to potential failure mechanisms, algorithms used for predicting failures and slope-failure susceptibility mapping.

Then investigators collected data on known slope failures in Carlton County in eastern Minnesota and Sibley County in south central Minnesota to identify failure-risk factors not found in the literature. Researchers reviewed various statewide data sets, identifying topographic, hydrologic and soils information that could be used in GIS-based modeling. Next, they developed a GIS-based slope-failure model by incorporating the available data with geotechnical theory and probability factors from hydrologic data, and writing computer code to allow the data to be input into mapping software.

Researchers tested the software on known failure sites to refine soil parameter selection and failure models. The refined models and software were then used to identify and map slope failure risks in Carlton and Sibley counties.

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A detailed GIS map of a length of County Highway 210, color-coded to show slope failure susceptibility along the roadway.

What Did We Learn?

After analyzing the literature and the failure and geotechnical data, researchers identified the following key causal factors in slope failure: slope angle, soil type and geology, vegetation, land use and drainage characteristics, soil moisture, and rainfall intensity and duration.

Researchers then developed mapping models for the two counties using three key data sets. The first was data from 3-meter resolution, high-quality lidar, which measures distances with laser range finders and reflected light, available through Minnesota’s Department of Natural Resources website. The team augmented this data with U.S. Department of Agriculture soils survey data, and with National Oceanic and Atmospheric Administration and National Weather Service hydrologic data for precipitation and storm duration information.

Based on research in geotechnical theory, researchers developed algorithms for anticipating failure and built these into the lidar-based topographic mapping model. They also developed input parameters based on the failure factors and established output parameters representing five levels of failure susceptibility: very low, low, moderate, high and very high.

After testing the GIS-based model against a slope along County Highway 210 in Carlton County, researchers confirmed that failure potential correlated well with documented or observed slope failure. The team further validated the model by applying it to several small areas in the adjacent Carver and Sibley counties, finding similarly effective correlation with identifiable failure sites.

Independent geotechnical experts examined the modeling software and further refined geotechnical, soil and hydrologic elements. Finally, the team developed maps of Carlton and Sibley counties that assigned failure susceptibility levels to slopes in the two counties. Viewing maps through the software remains the most useful way to examine slopes, although large-format maps are available.

“If county engineers have higher slopes adjacent to roadways, they can use this basic tool to predict slope failures and then hire a geotechnical consultant to investigate the site.” – Tim Becker, Public Works Director, Sibley County

What’s Next?

With additional funding, mapping could be extended to every county in Minnesota to further refine failure modeling. Maps may also be useful in identifying structures such as roadways, ecological features, transmission lines and pipelines, bridges and culverts that may be threatened by slope failure susceptibility. Potential risks could be used to prioritize slope treatment plans.

This research effort is part of a slope failure risk mitigation strategy that includes the recently released Slope Stabilization Guide for Minnesota Local Government Engineers. Another project, underway at MnDOT, is identifying, mapping and ranking slopes vulnerable to slides that could affect the state highway network. The project

This post pertains to the Local Road Research Board-produced Report 2018-05, “Storm-Induced Slope Failure Susceptibility Mapping,” published January 2018. More information is available on the project page.

Using a National Database to Develop Performance Metrics for Local Pavement Markings

Pavement marking performance metrics from a new study will help Minnesota local agencies save time and money by choosing longer-lasting pavement marking products.

Researchers developed pavement marking performance metrics for Minnesota local agencies to use as a guide to make better pavement marking product decisions. The metrics were developed based on an analysis of survey data collected from Minnesota local agencies and MnDOT pavement marking data mined from the National Transportation Product Evaluation Program (NTPEP). Findings showed differences in product performance with regard to retroreflectivity and service life, which were impacted by variables such as road surface type, year of application, traffic volume and type of pavement marking.

“There would be great potential savings in using pavement marking products with a longer service life. Mining NTPEP data to analyze product performance has not been done before and should contribute substantially to this goal,” said Omar Smadi, Director, Iowa State University Center for Transportation Research and Education.

What Was Our Goal?

The goal of this research was to develop pavement marking performance metrics for Minnesota local agencies to use as a guide when choosing the most durable and cost-effective products. Researchers developed the pavement marking performance metrics, specifically for retroreflectivity and service life, by analyzing existing MnDOT data mined from NTPEP. They also used the findings to make recommendations for future pavement marking research to support local agency needs.

What Did We Do?

Researchers designed and conducted a survey to assess pavement marking products used by local agencies in the state. Then they extracted 2010 and 2013 MnDOT pavement marking data from NTPEP to analyze the performance of products that survey respondents identified as commonly used.

NTPEP data included products tested at two different sites and applied on different road surfaces. Researchers analyzed performance with regard to retroreflectivity and deterioration or longevity of the materials under various conditions, such as road surface type, year of application, traffic volume and type of pavement marking. Based on results from the analysis, researchers developed performance metrics for Minnesota local agencies to use as a guide for choosing particular pavement marking product types.

What Did We Learn?

From the survey results, researchers learned that the majority of Minnesota local agencies use either latex or epoxy as their primary pavement marking material. However, epoxy and tape outperformed latex at all levels of conditions and provided a service life of three years or more.

A few survey respondents also reported grooving as a method that seemed to extend the service life of latex paint markings. Researchers were unable to investigate the impact of grooving, however, since MnDOT grooving data was not accessible.

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Grooving may extend the service life of pavement marking materials.

From the NTPEP data analysis, researchers concluded the following:

  • White markings had significantly higher initial retroreflectivity and slower deterioration than yellow markings.
  • Road surface type does not significantly impact retroreflectivity throughout its service life.
  • Epoxy has higher retroreflectivity than latex materials.
  • As expected, markings on wheel zones deteriorated faster, reducing retroreflectivity over time.
  • Deterioration values of markings varied among different test sites, which may be attributed to differences in average annual daily traffic (AADT) values (10,000 in 2010 versus 37,000 in 2013) or installation practices.

“The findings from this research will be beneficial for Minnesota local agencies in determining which pavement marking materials are most effective,” said Kate Miner, then-Scott County Traffic Manager.

What’s Next?

Although the product performance metrics data will help Minnesota local agencies make better pavement marking product decisions in less time, researchers recommend developing a guidebook to make the information more usable. Adding grooving data to the guidebook would also be beneficial to investigate the potential impact grooving provides in extending the service life of pavement markings.

Researchers also recommend testing the same products evaluated in this research on low-volume local roads and on challenging surface types. MnDOT NTPEP data only included products that were tested on high-volume freeways.

This blog pertains to the Local Road Research Board-produced Report 2017-43, “Minnesota Local Agency Pavement Marking: Mining Existing Data,” published November 2017. A related project has developed a spreadsheet tool to help local agencies prioritize pavement markings on low-volume roads.

Smartphone prototype app warns drivers of high-risk curves

Lane-departure crashes on curves make up a significant portion of fatal crashes on rural Minnesota roads. To improve safety, solutions are needed to help drivers identify upcoming curves and inform them of a safe speed for navigating the curve.

“Traditionally there are two ways to do this: with either static signage or with dynamic warning signs,” says Brian Davis, a research fellow in the U of M’s Department of Mechanical Engineering. “However, while signing curves can help, static signage is often disregarded by drivers, and it is not required for roads with low average daily traffic. Dynamic speed signs are very costly, which can be difficult to justify, especially for rural roads with low traffic volumes.”

In a recent project led by Davis on behalf of MnDOT and the Minnesota Local Road Research Board, researchers developed a method of achieving dynamic curve warnings while avoiding costly infrastructure-based solutions. To do so, they used in-vehicle technology to display dynamic curve-speed warnings to the driver based on the driver’s real-time behavior and position relative to the curve. The system uses a smartphone app located in the vehicle to provide the driver with visual and auditory warnings when approaching a potentially hazardous curve at an unsafe speed.

“Highway curves [make up] 19 percent of the total mileage of the paved St. Louis County highway system, yet these curves account for 47 percent of all severe road departure crashes,” says Victor Lund, traffic engineer with St. Louis County. “In-vehicle warnings will be a critical strategy to reduce these crashes.”

To begin their study, researchers designed and tested prototype visual and auditory warning designs to ensure they were non-distracting and effective. This portion of the study included decisions about the best way to visually display the warnings and how and when audio messages should be used. “To create the optimal user experience, we looked at everything from how to order the audio information and when the message should play to the best length for the warning message,” says Nichole Morris, director of the U’s HumanFIRST Lab and co-investigator of the study.

Next, a controlled field test was conducted to determine whether the system helped reduce curve speeds, pinpoint the best timing for the warnings in relation to the curves, and gather user feedback about the system’s usefulness and trustworthiness. The study was conducted with 24 drivers using the test track at the Minnesota Highway Safety and Research Center in St. Cloud, Minnesota. The selected course allowed drivers to get up to highway speeds and then travel through curves of different radii, enabling researchers to learn how sensitive drivers are to the position of the warnings.

Based on the study results, the system shows both feasibility and promise. “Our in-vehicle dynamic curve warning system was well-liked and trusted by the participants,” Davis says. “We saw an 8 to 10 percent decrease in curve speed when participants were using the system.”

The project was funded by MnDOT and the Minnesota Local Road Research Board.

A Look at Local Bridge Removal Practices and Policies

Many local agencies in Minnesota lack funding to construct and maintain all the bridges in their roadway network. One way to lower costs is to reduce the number of bridges.

In Minnesota, some township bridges are on roads with low usage that have alternative accesses for nearby residents, but local officials are reluctant to remove the bridges.

To identify possible changes to how redundant and low-use bridges are identified and removed in Minnesota, the Local Road Research Board conducted a transportation research synthesis, “Local Bridge Removal Policies and Programs,” that explores how other states make bridge removal decisions.

Fifteen state DOTs responded to a survey about their processes, with varying levels of state oversight identified for bridge removal decisions. Researchers also examined funding and incentives offered by some DOTs to local agencies for bridge removal, as well as criteria for considering bridge removal.

A literature search of bridge design manuals, inspection manuals and bridge programs was also conducted to identify related policies and programs.

Read the TRS to learn more about the various bridge removal policies and procedures in place in Minnesota and other states.

A look at five great environmental research projects

To mark Earth Day 2016, MnDOT Research Services is taking a glance at five stellar examples of current research projects at MnDOT that involve pollution control, wetland mitigation, road salt reduction and new ways of recycling pavement.

1: Reducing Road Construction Pollution by Skimming Stormwater Ponds 

Temporary stormwater ponds with floating head skimmers can remove clean water from the surface of a settling pond.

Soil carried away in stormwater runoff from road construction sites can pollute lakes and rivers.

Stormwater settling ponds provide a place for this sediment to settle before the water is discharged into local bodies of water. However, since stormwater ponds have limited space, a mechanism is needed to remove clean water from the pond to prevent the overflow of sediment-laden water.

MnDOT-funded researchers designed temporary stormwater ponds with floating head skimmers that can remove clean water from the surface of the settling pond, using gravity to discharge water into a ditch or receiving body.

The study, which was completed in spring 2014, identified five methods for “skimming” stormwater ponds that can improve a pond’s effectiveness by 10 percent. MnDOT researchers also created designs for temporary stormwater ponds on construction sites with the capacity to remove approximately 80 percent of suspended solids.

These designs will help contractors meet federal requirements for stormwater pond dewatering. Researchers also determined how often a pond’s deadpool must be cleaned, based on watershed size and pool dimensions.

2: Roadside Drainage Ditches Reduce Pollution More Than Previously Thought  

Photo of roadside ditch
Stormwater infiltration rates at five swales were significantly better than expected based on published rates.

Stormwater can pick up chemicals and sediments that pollute rivers and streams. Roadside drainage ditches, also known as swales, lessen this effect by absorbing water. But until recently, MnDOT didn’t know how to quantify this effect and incorporate it into pollution control mitigation measures.

In a study completed in fall 2014, researchers evaluated five Minnesota swales, measuring how well water flows through soil at up to 20 locations within each swale.

A key finding: grassed swales are significantly better at absorbing water than expected, which may reduce the need for other, more expensive stormwater management practices, such as ponds or infiltration basins.

This could save MnDOT and counties significant right-of-way and construction costs currently expended on more expensive stormwater management techniques.

3: Could Permeable Pavements Eliminate Road Salt Use on Local Roads? 

Robbinsdale
Even with little or no road salt, a permeable pavement like this porous asphalt in Robbinsdale, Minnesota, collects little slush and snow in the winter because it warms well and remains porous enough to infiltrate surface water effectively.

Road salt is used for de-icing roadways during winter months, but can have a negative impact on the environment.

This research, which was just approved for funding through the Minnesota Local Road Research Board in December 2015, will investigate the reduction in road salt application during winter months that can be attained with permeable pavements, while still providing for acceptable road safety.

Some initial investigations (see previous study) suggest that road salt application can be substantially reduced, even eliminated, with permeable pavement systems. The proposed research will investigate this hypothesis more thoroughly, and further document the reduction in road salt application that can be expected with permeable pavement.

4: Highway 53 Shows Potential of Using Road Construction Excavation Areas For Wetland Mitigation

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This photo from spring 2015 shows that wetlands have begun to take hold along Highway 53.

Road construction in northeast Minnesota often causes wetland impacts that require expensive mitigation. However, borrow areas excavated for road construction material can be developed into wetland mitigation sites if hydric vegetation, hydric soils and adequate hydrology are provided. Fourteen wetland mitigation sites were constructed north of Virginia, Minnesota along the U.S. Trunk Highway 53 reconstruction project corridor and evaluated for wetland.  The sites were established with the goal of mitigating for project impacts to seasonally flooded basin, fresh meadow, shallow marsh, shrub swamp, wooded swamp, and bog wetlands. All but one of the sites consistently meet wetland hydrology criteria.

The sites contain a variety of plant communities dominated by wet meadow, sedge meadow, and shallow marsh. Floristic Quality Assessment (FQA) condition categories for the sites range from “Poor” to “Exceptional.”

According to the research report published in March 2016, these sites have shown the potential for creating mitigation wetlands in abandoned borrow pits in conjunction with highway construction. Adaptive management, particularly water level regulation, early invasive species control, tree planting, and continued long-term annual monitoring can make mitigation sites like these successful options for wetland mitigation credit.

5: Recycling Method Could Give Third Lives to Old Concrete Roads 

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This photo shows a cold in-place recycling equipment train in action.

MnDOT already extends the lives of some old concrete highways by paving over them with asphalt instead of tearing them up. Now MnDOT hopes to add a third life for these old concrete roads by using a process called cold in-place recycling to re-use that existing asphalt pavement when it reaches the end of its life.

Cold in-place recycling (CIR) uses existing pavements, without heat, to create a new layer of pavement. It involves the same process of cold- central plant mix recycling (which is being employed by MnDOT for the first time on two shoulder repair projects this year), but it is done on the road itself by a train of equipment. It literally recycles an old road while making a new road.

CIR has been in use in Minnesota for 20 years, but only with hot-mix asphalt (HMA) over gravel roads. The purpose of a new study, which was approved for funding in April 2016, is to validate Iowa’s promising new practice using CIR on bituminous over concrete.

In this research project (see proposal), MnDOT will use cold-in-place recycling to replace the asphalt pavement on a concrete road and then evaluate it for several years, comparing it also with control sections.

Along with the potential of a better service life, the cost of CIR is much lower than new hot mix asphalt (HMA). Therefore, a 20-percent to 30-percent price reduction per project may be realized.

MnDOT, LRRB select new research projects with eye toward results

MnDOT’s latest crop of transportation research projects have been identified. This year, researchers were asked to pay special attention to how their work could benefit the public and be put into real-world practice.

MnDOT’s Transportation Research Innovation Group (TRIG) and the Minnesota Local Road Research Board recently announced their Fiscal Year 2017 funding awards after hearing proposals from researchers at multiple universities. The two bodies chose 20 research proposals totaling about $2.9 million that will study new and innovative approaches to improving the environment, making transportation systems safer, improving construction methods and operating in more cost-effective ways.

According to MnDOT Research Management Engineer Hafiz Munir, MnDOT Research Services made some key changes to its annual requests for proposal that will help ensure research makes a difference to the agency’s bottom line. This year, researchers were asked early on in the proposal process how they would quantify their results, what benefits the research could achieve and how their research could be implemented in the future.

“Now we’ll be able to track those metrics and that will help MnDOT not only quantify the potential benefits of the projects, but also implement the results,” Munir said. “The bottom line is that we will be able to not only save money, but also improve the way MnDOT does business.”

Several of the 20 newly funded projects deal with improving transportation safety, Munir said, and many others are focused on implementing cost-saving practices, innovations and new technologies.

The projects approved in December 2015 will do the following:

  • Create an inexpensive GPS-based system that alerts the driver when a motor vehicle deviates from a lane or approaches a curve. (Project summary)
  • Find out whether a smartphone app can effectively warn drivers about upcoming roadway curves. (Project summary)
  • Determine whether different types of roadway turfgrass are better suited for specific regions of the state. (Project summary)
  • Create a comprehensive design guide for fish-friendly culverts.  (Project summary)
  • Determine how social media can be used to engage diverse community groups within the state. (Project summary)
  • Investigate the performance of the state’s first glass fiber reinforced polymer (GFRP) reinforced bridge deck, slated for construction in 2016.  (Project summary)
  • Develop signage recommendations to slow high-speed traffic as it approaches roundabouts.  (Project summary)
  • Gather truck reliability data, identifying truck bottlenecks and providing potential mitigation solutions for regular congestion areas. (Project summary)
  • Determine why anchor bolts are becoming loose on overhead signs, light towers and other support structures — and how to prevent it.  (Project summary)
  • Establish a system and smartphone app for accurately capturing and reporting data about intrusions into work zones.  (Project summary)
  • Develop an advanced sensor system to estimate long-term and dynamic vertical displacements on the I-35W bridge. (Project summary)
  • Investigate the necessity of pavement markings on low-volume roads and develop an approach to prioritize pavement marking projects.  (Project summary)
  • Compare the performance of different structural fibers in thin concrete overlays.  (Project summary)
  • Evaluate four performance test methods that predict the cracking behavior of asphalt mixes. (Project summary)
  • Investigate the link between transportation investment and job creation, and analyze transportation investments, business patterns and socioeconomic data in Minnesota counties. (Project summary)
  • Refine a taconite-based pothole repair compound, and develop a low-cost mechanized system to mix and place it in large quantities.(Project summary)
  • Investigate how much road salting can be safely decreased with the use of permeable pavements. (Project summary)
  • Evaluate the use of iron-enhanced check dams for capturing phosphate and toxic materials from roadway runoff. (Project summary)
  • Improve accessibility calculation capabilities and understanding of travel behavior by integrating data about highway bus operations, park-and-ride facilities, and urban parking costs. (Project summary)
  • Investigate the concept of estimating traffic volumes from mobile device samples to collect traffic data inexpensively. (Project summary)

Munir said the next steps for these projects this spring include creating  technical advisory panels, finalizing project work plans and preparing contracts. Some projects could begin early, depending on available funding and project-readiness. By the time Fiscal Year 2017 begins on July 1, funding will be available to begin all 20 projects.

New Tool Measures Impact of Heavy Trucks

A new tool developed by the Local Road Research Board helps cities and counties assess how much increased heavy vehicle traffic affects local roads.

Researchers created an analysis method and corresponding spreadsheet tool that city and county engineers can use to calculate the impact of heavy vehicles on asphalt roads beyond what was planned in the original pavement design.

The information will help agencies optimize services, such as garbage collection, for the least amount of damage. It will also help agencies better plan roads in new developments, as well as redesign existing roads that are nearing the end of their lives.

Lack of Data

Heavy trucks cause local roads to deteriorate more quickly than passenger vehicles, but it is challenging to quantify the impacts, especially for areas where traffic was not forecast at the time a road was designed.

Many local engineers in Minnesota have requested information about the impact of heavy vehicles in light of new construction, commercial distribution facilities and hauling routes. This information is needed to assist in local road planning and maintenance.

Two Methods

In a newly completed study, investigators developed two methods for calculating heavy vehicle impact:

  • Calculate the additional bituminous material (and associated costs) that would have been required to construct the pavement had the heavy truck traffic been predicted when the pavement was designed.
  • Calculate the portion of a pavement’s design life, measured in equivalent single-axle loads (ESALs), consumed by unanticipated vehicles.

“Before this project, there wasn’t an easy way for an engineer to determine how much a specific truck was going to decrease the life of a road,” said  Deb Heiser, Engineering Director, City of St. Louis Park.

Whereas previous research has calculated the impact of extremely heavy vehicles over the short-term (typically the course of a construction project), this project calculates the impact of long-term increases in traffic from vehicles that are heavy, but still mostly within normal legal weight limits.

The tool can be used for a single street segment or an entire road network. Users can also compare current situations with proposed ones to evaluate the impact of potential changes in heavy traffic levels.

Related Resources

The Local Road Research Board is now on YouTube

The Local Road Research Board, Minnesota’s unique city- and county-funded transportation research program, now has its own YouTube channel.

The LRRB has been around since 1959, funding research into transportation issues that affect local governments in Minnesota. In recent years, the LRRB has also produced a number of videos designed to educate the public and to provide training to local transportation practitioners.

Check out the latest videos and subscribe to the LRRB channel by clicking here.

Why is all the colored concrete deteriorating so fast?

There’s nothing like colored concrete to make a crosswalk, sidewalk or breezeway look snazzy.

But the extra touch that many cities are putting into their downtown streetscapes may not be so pretty in just a few short years.

Early cracking has prompted the city of Vadnais Heights to tear up its colored concrete, and the city of Centerville — which installed colored concrete only six years ago — plans to follow suit, said MnDOT’s Senior Road Research Engineer Tom Burnham.

Both cities participated in a recent study, sponsored by the Local Road Research Board and conducted by MnDOT, to determine what is causing the early deterioration.

Across Minnesota, many of the estimated 45 colored concrete projects have experienced early deterioration, particularly microcracking near contraction joints. While this type of distress also occurs with regular concrete, it appears to be accelerated in the colored concrete projects, within five years in some instances.

Although the newly released study identifies likely causes for the failing colored concrete, further research is needed to evaluate proposed solutions.

Findings

Researchers determined that the colored concrete mixtures have likely been too porous for Minnesota winters, allowing deicing chemicals to leach in and wreak havoc. Although not quite as problematic for sidewalks and medians — which aren’t salted as heavily — it is especially bad for colored crosswalks.

A denser concrete mixture (one formed with less water) is recommended; however, constructing the concrete panels this way will require extra steps.

“There are chemicals that can be added to the mixture to artificially lower that water-to-concrete ratio,” Burnham said. “This will allow a  denser mixture to be more easily placed.”

The city of Centerville plans to tear up its colored concrete. This photo shows early joint deterioration.
The city of Centerville plans to tear up its colored concrete. This photo shows early joint deterioration.
Color in vogue

Although there was a spate of colored concrete construction in Ramsey County in the late 1990s, it has only come into fashion in the rest of the state within the last five to six years, according to Burnham.

“You go to almost any community and they’re installing it — on their sidewalk and medians and also crosswalks,” said Burnham, who coordinated the research study.

Because of the added expense, cities may be very disappointed in the results.

The city of Stillwater, which installed a colored concrete panel crosswalk on its main street just two years ago (see top photo), is already experiencing cracking and deterioration in several panels.

Possible remedies

Although reducing the porosity of the colored concrete mixture should help,  it won’t solve everything.

Another issue is the curing. The typical white curing product can’t be applied like it is with standard concrete, so curing the colored panels is more challenging, Burnham explained.

There are possible remedies, however, to assist with the curing, such as wet burlap or curing blankets.

Adding complexity to the issue are the new deicing chemicals on the market, which are also impacting regular road materials.

Several test samples showed evidence of chemical attack of the cement paste and fine aggregates, as well as an alkali-silica reaction, which can cause cracking or spalling and isn’t normally seen in regular concrete.

“Is there anything unique with the coloring that would accelerate the observed chemical reactions? We didn’t feel we had enough samples and knowledge at this point to conclusively say,” Burnham said.

Different construction techniques could go a long way toward increasing the livelihood of colored concrete; however, it could take several years of observation to determine if other methods work.

MnROAD is considering adding colored concrete panels to its facility for testing.

Until more questions are answered, MnDOT researchers are recommending repair techniques and alternative streetscaping ideas to cities, such concrete stains, pavers or colored high friction surface treatments.

In addition to sharing the findings with cities and counties, Burnham wants to educate contractors.

“We hope this research is a wake-up call for the colored concrete industry too because we don’t want the industry to die in Minnesota,” he said. “If it can work, we want cities and counties to be able to use it.”

*Editor’s Note: This story was updated 09/04/2014 to specify that this research project was funded entirely by the Local Road Research Board, and that MnDOT conducted the research.

Related Resources
  • Investigation and Assessment of Colored Concrete Pavement — Final Report (PDF, 20 MB, 368 pages); Technical Summary (forthcoming)

Program offers funding for “homegrown” road maintenance ideas

Attention Minnesota road maintenance staff:

Have you ever dreamed that all of your tinkering, fussing, and fiddling in the shop and on the road could help improve every road in Minnesota? Do you need funding to improve your sign maintenance and installation process? Or maybe you’ve come up with an idea for a new tool for controlling roadside vegetation or a design for a more effective work-zone safety product. Whatever it is, the Local Operational Research Assistance (OPERA) Program wants to hear about it.

Funding for 2015 OPERA projects is now available, and it’s easy to submit a proposal. Simply fill out the brief proposal application (50 KB DOC) and submit it via e-mail to Mindy Carlson at Minnesota LTAP. There isn’t a deadline to submit your proposal, but FY15 funds are limited and they often go quickly.

The maximum funding per project is $10,000, and local agencies are welcome to submit more than one proposal.

Project Guidelines

Your proposed research project should focus on the timely development of relevant ideas or methods that improve transportation or maintenance operations. Our goal is to collect and disseminate homegrown, innovative solutions to the everyday challenges our transportation workforce faces on the job. Counties, cities, and townships, this is your opportunity to encourage your maintenance staff to become actively involved in researching and testing their ideas.

To see what other local agencies have done with OPERA funding, check out our fact sheets and annual reports, or watch these videos highlighting previous OPERA projects:

Program Sponsors

The Local OPERA Program is funded by the Minnesota Local Road Research Board and administered by the Minnesota Local Technical Assistance Program.