Over time, asphalt pavement becomes stiff and brittle due to oxidation, often leading to surface cracking and distress. To mitigate these damages and extend the service lives of roads, transportation agencies may apply a spray-on rejuvenator (SOR) to restore essential components of the asphalt. This project investigated the short- and long-term effectiveness of 12 SORs that state and local transportation agencies may consider for future use.
Continue reading Assessing Rejuvenators That Extend Pavement Service LifeTag Archives: LRRB
Increasing Equity in Transportation Investments
Historically, equity has not been a primary objective in the transportation infrastructure investment planning process. By effectively incorporating equity into the process, underserved communities and Native nations can realize increased benefits from transportation improvements. This research explored effective strategies for incorporating equity in transportation capital investment planning and provides guidance to transportation agencies, planning organizations and Native nations.
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Evaluating Taconite as a Lower Cost Friction Treatment
High friction surface treatments (HFSTs) on Minnesota roads are composed of imported, industry standard calcined bauxite aggregate. This material is expensive, and producing it is energy-intensive. Taconite aggregate, a by-product of the Minnesota mining industry, is a potential alternative to calcined bauxite that is less expensive. This research compared taconite and calcined bauxite in field skid resistance performance testing to determine the feasibility of using taconite in place of calcined bauxite in HFST applications.
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Evaluating Road Designs That Use Lower Quality Aggregate
Aggregate materials used in the base and subbase layers of pavements provide structural support and drainability to Minnesota roads. But the supply of locally available high-quality aggregate material is becoming increasingly scarce. This project explored sustainable and cost-effective solutions for constructing durable flexible pavement roads with lower quality aggregate material.
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Developing Biochar Specifications for Stormwater Management
Effective stormwater management helps keep roadway contaminants from entering Minnesota’s lakes and streams. Management practices include soil and vegetation in roadside bioretention systems that filter heavy metals and hydrocarbons created by vehicles. Based on other studies, retention and transformation of roadside pollutants should be improved by biochar application to existing or engineered soils. Abundant sources of biomass can be used to produce biochar, a soil amendment with numerous benefits. MnDOT and local agencies identified biochar specifications for effective use in stormwater treatment to support the next phase of testing and development of biochar design guidance.
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Evaluating Strategies to Prevent Early-Age Bridge Deck Cracking
Premature cracking in reinforced concrete bridge decks is expensive to repair and may lead to rapid bridge deterioration. Despite changes to mix designs, transverse cracking after casting continues to be a problem in Minnesota. This project evaluated alternative concrete mix designs and reinforcement strategies to mitigate early-age bridge deck cracking, reduce maintenance costs and extend bridge deck service lives.
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Increasing School Bus Stop-Arm Compliance
A significant number of school bus stop-arm violations occur every day throughout the country. In Minnesota, violation and citation data suggests these incidents are grossly underreported and underenforced due to a time-consuming reporting and enforcement process. This project examined current processes and recommended improvements to encourage higher rates of reporting and enforcement.
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Testing Recycled Plastics in Asphalt and Concrete Pavement Mixes
Addressing the increasing need for pavement materials coincides with an increasing supply of plastic waste. Incorporating recycled plastic into aggregate for transportation infrastructure is of growing interest. Testing plastic waste material in both asphalt and concrete pavement mixtures revealed promising results and the need to explore long-term performance and durability.
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Evaluating the Friction of Pavement Markings and Colored Pavement
Pavement markings make travel safer for all road users. However, the material used for retroreflectivity can be slicker than the surrounding pavement. To maximize the safety of bicyclists, motorcyclists and pedestrians, MnDOT and local agencies explored the friction values of different marking materials. Project results produced valuable information on relative friction between pavement and marking materials and, importantly, identified effective testing tools to evaluate and compare products.
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Utilizing Recycled Tires to Treat Stormwater
Repurposing old tires as tire-derived aggregate (TDA) is a stormwater management practice that could retain phosphate in underground treatment systems and prevent it from reaching the soil, surface waters and groundwater. However, chemicals from the TDA may leach into the soil and water sources. This project identifies the environmental impacts and cost-effectiveness of deploying TDA to manage stormwater in Minnesota cities and counties.
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Crossroads 