Cost Estimate of B vs. C Grade Asphalt Binders
Principal Investigator(s):Mihai Marasteanu, Professor, Civil, Environmental and Geo-Engineering
- Manik Barman, Associate Professor, UMD-Civil Engineering
Polymer modified binders (PMB) have been shown over the decades to have superior rheological and mechanical properties compared to unmodified asphalts. However, the higher costs of PMBs have prevented a wider use of these materials. While for high-traffic roads the choice of superior products is more obvious, for lower-volume roads there isn't always enough information to allow engineers to determine if using a PMB is cost effective in the long run. For example, for a job of 50,000 t, a difference of $12 per ton results in an additional cost of $600,000, which is very significant for local roads authorities.
In Minnesota, the necessity of understanding the benefits of using polymer modification, which provides superior resistance to cracking, is even greater since asphalt pavements largely fail due to low-temperature cracking. Many local agencies use polymer modified binders, mainly PG 58H-34 (Grade C), in the asphalt mixtures for the wearing course, which reduce the occurrence of transverse cracking. However, the answer to the question: "How cost effective is the use of the Grade C binder, especially when compared to the cheaper PG 58S-28 (Grade B) binder?" is not known.
The main goal of this research is to provide a well-informed answer to the above question. This will be accomplished by documenting and analyzing existing performance data, reviewing relevant case studies, performing experimental work on various asphalt binders and mixtures to evaluate their low-temperature cracking resistance, and conducting a benefit-cost analysis to provide recommendations on when to use Grade B and Grade C for lower volume roads.