Category Archives: Materials and Construction

Quantifying the Effect of Geogrids in Asphalt Pavement Foundation Layers

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.

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New Project: Evaluation of Corrugated HDPE Pipes Manufactured with Recycled Content

Historically, federal regulations have required that MnDOT use pipes made with all-new materials in various applications, such as redirecting stormwater under roadways. However, recent changes to these regulations have made it possible for the agency to also consider pipes made with recycled materials, which could provide MnDOT with more options when choosing products for future projects.

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New Project: Evaluation of Proprietary Rejuvenators

A wide range of proprietary spray-on asphalt rejuvenators are available on the market. A National Road Research Alliance field study has been initiated to monitor the performance of some vendors’ materials on test sections over the next five to 10 years. Local agencies are interested in learning more about the many products on the market.

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New Project: Pavement Marking/Colored Pavement Friction Differential and Product Durability

Pavement markings contain glass media to provide retroreflectivity. These markings are slipperier than surrounding pavement. The sudden difference in friction between pavement and pavement markings can create a safety hazard for pedestrians (including those with disabilities), bicyclists and motorcyclists, especially during wet conditions.

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New Project: Benefits of Preventive Concrete Pavement Maintenance

Early preventive maintenance of concrete pavement—maintenance performed in the first five to seven years of pavement life—is a low-cost way to increase pavement service life. But no quantitative evaluations of service life extension have been conducted that compare early intervention to late or no intervention.

Without these comparisons, meaningful determinations of pavement life extension operations cannot be made. Federal Highway Administration (FHWA) research has found that agency projects focused on the end-of-service life may redirect funds from rehabilitation projects that could improve overall system quality.

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Evaluating Cracking Resistance Test Methods for Asphalt Pavements

A new method of testing low-temperature cracking in asphalt pavement shows promise for design, quality control and quality assurance. Test results produced by the new method, which is faster and less expensive than the previous method, match well with results from the older method. 

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Evaluating the Impact of J-Band on Pavement Service Life and Crack Resistance

Potholes and other pavement failures in asphalt typically occur at the seams between lanes, where the mixture loses density during compaction because the edges are not confined like they would be with cement concrete forms. Researchers found that spraying J-Band, a void-reducing asphalt membrane (VRAM), in a band along longitudinal joints before asphalt layers are applied increased bond strength, lowered permeability and air void levels, and improved crack resistance.

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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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