Comparing the Cost-Effectiveness of Asphalt Binders for Local Roads

This Technical Summary pertains to Report 2023-19, \u201cCost Estimate of B vs. C Grade Asphalt Binders,\u201d published May 2023. More information is available at mdl.mndot.gov.Polymer-modified binders (PMB) have been shown over the decades to improve the mechanical properties of asphalt mixtures compared to unmodified binders. Considering its higher initial cost, selecting the best alternative is very important, especially for local agencies, given their limited budgets. A challenge in the materials selection process for low volume roads is the limited information available, which could allow engineers to determine if using PMBs is cost-effective. In this research effort, we investigate the use of PG 58H-34 PMB binders (grade C) and PG58S-28 unmodified binders (grade B) for low volume roads in Minnesota. Historical pavement performance data were analyzed to compare the field performance of modified and unmodified mixtures. Laboratory experiments were performed to compare the low-temperature cracking properties of polymer-modified and unmodified binders and mixtures commonly used in Minnesota. Based on the experimental results, a life cycle cost analysis (LCCA) was performed comparing the use of polymer-modified and unmodified binders for low volume roads in Minnesota. The results show that using PMBs for new construction is expected to extend the pavement service life by six years, and that using PMBs is more cost-effective than using unmodified binders for low-traffic roads

Best Practices for Improving Subgrade Drainage

This project developed a high-level best practices guidance document for the design/installation of subsurface drainage. This Tool serves as a guide to assist agencies in understanding drainage problems and options to consider for mitigating structural damage to pavements due to moisture. The weather and soil conditions vary drastically across Minnesota. Engineers should use their engineering judgment and seek expert guidance when necessary