Originally published in CTS News, March 19, 2025
Thin pavements—in which new pavements are constructed over an existing base layer—can be an economical option for low- and moderate-volume roads. However, thinner concrete roads are prone to distress caused by weather and traffic loads. The solution, U of M researchers found, may be to add small synthetic fibers to the concrete.
Continue reading Adding fibers to concrete may help create long-lasting roadsFull-depth reclamation (FDR)—an effective and efficient pavement reconstruction method—can be made even more sustainable by strengthening the road base. Laboratory and field testing of proprietary stabilizers used to amend FDR material illustrated improvements in pavement stiffness and economic benefits over time. New pavement design standards for base stabilizers can guide road engineers in choosing the optimal products for sustainable roads.
Continue reading Understanding the Performance of Road Base Stabilization AdditivesPavement durability depends on its density. Achieving adequate density depends on the size of the aggregate in the mixture and the asphalt lift thickness—the height of the asphalt layer that is applied by the paver and compacted.
Continue reading New Project: Impact of Asphalt Lift Thickness on Pavement Density and DurabilityMnDOT uses geosynthetic materials to stabilize or reinforce road pavements. Various types of geosynthetics help maintain separation between pavement layers, improve drainage and prevent erosion.
Continue reading New Project: Quantify the Benefits of Using Geotextiles and Geogrids to Improve the Performance of Unbound Pavement LayersHigh Friction Surface Treatments (HFST) are pavement treatments that involve applying a high-quality aggregate and binder to pavement surfaces to help maintain friction. The treatment has significantly reduced crashes and injuries in wet and dry road conditions in high crash areas. However, HFST can be a costly treatment. Researchers, funded by MnDOT and the Local Road Research Board, are evaluating if taconite, a readily available Minnesota byproduct, can be an effective alternative treatment in low volume areas.
Continue reading Testing High Friction Aggregates using SCRIM Technology at MnROADMnDOT continues working on systematically and proactively assessing stability of slopes along its highway system. Efforts are aimed at minimizing the potential for slope failures that could result in threats to public safety and costly repairs.
Continue reading New Project: Vulnerability Assessments of Critical Slope Areas Using Advanced Monitoring TechniquesChip seals are an economical road surface treatment that MnDOT and counties use to enhance existing pavement performance and service life. A thin layer of asphalt emulsion sprayed on the pavement surface and mixed with aggregate chips can address minor pavement distresses and seal the pavement surface to reduce the impacts of further wear.
Continue reading New Project: Long-Term Field Performance Evaluation of Chip SealsTaken from TRB Weekly – June 25, 2024
Per- and polyfluoroalkyl substances (PFAS) are a class of more than 6,000 contaminants of emerging concern that can harm both ecosystems and human health. These anthropogenic compounds contain carbon–fluorine bonds that make them stable and persistent in the environment, earning them the nickname “forever chemicals.”
Continue reading PFAS “Forever Chemicals” Can be Reduced in Highway Construction and Maintenance ProjectsCracking and spalling of concrete pavements reduce the service life of the roadway and result in added costs to an agency and disruptions to the traveling public when the damage is repaired.
Continue reading Solutions to Mitigate Dowel/Tie-Bar Propagated Cracking – Phase 1To address climate change mitigation goals, highway agencies are seeking alternative concrete paving mixtures that have a reduced embodied carbon content (ECC).
The research team first focused on developing a matrix of reduced ECC concrete mixtures to be tested at MnROAD. The 16 concrete mixtures selected for inclusion in the test matrix met minimum engineering requirements to ensure constructability and performance and were approved by MnDOT.
Between July 27 and August 9, 2023, 16 test cells were constructed at the MnROAD I-94 facility to evaluate reduced ECC concrete paving mixtures. The purpose of constructing these cells was to assess the in-service performance, environmental impact, and constructability of various alternative supplementary cementitious materials (ASCMs) that may reduce the embodied carbon content of concrete, while providing an opportunity to assess test results and in-service performance in coming years.
A preliminary environmental assessment showed that most mixtures were expected to have either a similar or lower ECC compared to the control mixture representative of typical MnDOT paving-grade concrete. Quality assurance testing conducted on field-cast specimens revealed generally acceptable results; most of the materials had similar performance compared to the control mixture, but the cells will continue to be monitored.
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