Cost Estimate of B vs. C Grade Asphalt Binders

Project summary:

Polymer-modified binders (PMB) have been shown over the decades to improve the mechanical properties of asphalt mixtures compared to unmodified binders. Considering the higher initial cost of PMB, 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 whether using PMB is cost-effective. In this research, the team investigated 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 lifecycle cost analysis (LCCA) is 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 PMB is more cost-effective than using unmodified binders for low-traffic roads.