Category Archives: Materials and Construction

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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Permeable Pavements Reduce Slippery Conditions During Winter Thaw

Road salt and particularly sodium chloride is used for de-icing roadways during winter months in cold climates but can have a negative impact on the environment. A recently completed research project by the Minnesota Local Road Research Board investigated the use of permeable pavements that are not treated with road salt as an alternative to impermeable pavement surfaces that are treated with road salt.

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New Project: Benefit/Cost of Applying a Higher Asphalt Film Thickness vs. Doing a Chip Seal at One Year

In Minnesota, reducing the effects of oxidation is a continuous challenge.

In a new study, funded by the Local Road Research Board, researchers will compare the effectiveness of two different methods: applying a surface treatment (typically a fog or chip seal) and increasing the asphalt film thickness during original construction.

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Asphalt Delivery Tracking Goes Digital with Some 2020 Construction Projects

MnDOT construction projects require tons of hot mix asphalt each year, with over 188 road and bridge projects in the 2020 construction season alone.

Historically, plant mixed asphalt has been weighed, tracked and paid for with computer-generated paper tickets. Paper ticketing isn’t an ideal process for a variety of reasons—on-site ticket collection poses safety risks, tickets can be easily lost, and data must be tabulated manually, just to name a few.

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Guidance for Working With Potentially Acid-Generating Materials

A new resource is available to help agencies greatly reduce the risk of disturbing potentially acid-generating (PAG) rock in places like northern Minnesota when conducting road projects. When exposed to air and water, PAG minerals can generate drainage that is hazardous to the environment. A MnDOT-sponsored research team developed a best practices manual that provides comprehensive steps to identify, mitigate and monitor PAG material during highway construction.  

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New Spreadsheet Tool Helps Agencies Manage Gravel Road Systems

The Minnesota Local Road Research Board has developed a new gravel road management tool — a simple, customizable spreadsheet for inventorying a gravel road system, tracking maintenance activity and expenditures, and budgeting and planning future needs.

A related user guide provides details about required inputs, gravel road evaluation protocols, and customization based on needs and available data.

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Taconite-Based Mixture Shows Further Promise for Repairing Potholes

Researchers have refined an innovative, quick pothole repair method for both concrete and asphalt pavements without using asphalt or cement materials. Based on taconite, a plentiful Minnesota material, the repair mixture can be applied fairly quickly and shows promise as a cost-competitive, long-term solution for potholes.

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Evaluating the Performance of CIR Mixtures With Reduced Binder Content

Researchers examined the practice of reducing the binder content of cold in-place asphalt recycling mixtures in the field on especially hot days to improve workability. Laboratory testing of mixtures at various temperatures and binder levels found the practice keeps mixtures workable, improves compaction and does not significantly diminish performance.

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High-Density Asphalt Pavement Mixtures Viable with local Aggregates

Researchers developed sophisticated models for high-density asphalt pavement mixtures. After calibrating the model to experimental data available from 5 percent air void asphalt mixtures, the research team conducted tests on three Minnesota mixtures to further refine the model. A Phase II study will develop multiple high-density mix designs for Minnesota applications.

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Using Debonded Strands to Reduce End Stress in Bridge Beams

A new MnDOT-funded research study has found that most agencies in states with weather similar to Minnesota’s use debonded strands in prestressed concrete bridge beams. MnDOT may begin piloting debonding as an alternative to draping, which manufacturers claim is time-consuming, challenging to worker safety and expensive.

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