Cargill is partnering with the National Center for Asphalt Technology (NCAT) in Opelika, Ala., and the Minnesota Department of Transportation’s (MnDOT) MnROAD program in Albertville, Minn., to determine how to best implement performance-engineered mix design procedures, especially in mixes containing rejuvenators and high levels of reclaimed asphalt pavement (RAP).
Results from the multi-year NCAT and MnROAD trials are expected to help state agencies gain confidence in performance-based testing. As part of the project, the researchers will compare blacktop made with Cargill’s Anova rejuvenator and a 45% RAP mix to control sections paved with a lower RAP mix, measuring factors such as pavement ride quality, cracking and rutting. By conducting parallel testing at both the NCAT test track and MnROAD test highway, scientists will be able to monitor results in both northern and southern climate extremes.
Mix design began earlier this year, as researchers from both facilities conducted extensive laboratory analysis on pre-construction samples. In early September, NCAT will pave a 200-ft-long section of its 1.7-mile oval pavement test track with the Anova/high RAP mix. There, scientists will evaluate the performance-engineered asphalt mix using an accelerated pavement testing protocol, subjecting the section to 10 million equivalent single-axle loads (ESAL) or about 10 years’ worth of traffic, in only two years. The NCAT test will be conducted in cooperation with the Virginia Department of Transportation.
The MnROAD project, slated to begin the week of Sept. 17, will cover two approximately 500-ft sections of the test highway. It is being done in conjunction with the MnDOT, which owns and operates the testing facility, and CRH/Hard Drives. Both test locations will conduct ongoing laboratory testing and field monitoring as they work to utilize various performance-engineered design protocols, while also assessing potential practical quality control tests that can be used when constructing pavements using such designs.