Investigation of the low-temperature fracture properties of three MnRoad asphalt mixtures

Principal Investigator:

Mihai Marasteanu, Associate Professor, Civil, Environmental and Geo-Engineering

Project Summary:

In this research effort, field cores were taken from cells 33, 34 and 35 at the MnROAD facility to determine the fracture properties of the field mixtures, to compare them with the laboratory-prepared mixtures analyzed in a previous study, and to evaluate the effect of aging at different depths in the asphalt layer. In addition, the properties of the recovered binders from the field cores as well as the properties of the original binders aged in laboratory conditions were investigated. The test results and the analyses performed indicate that the fracture tests performed on asphalt binders and asphalt mixtures have the potential to predict the field performance of asphalt pavements with respect to thermal cracking. The binder results confirm the predictions of the current performance grading system; however, it appears that the fracture resistance of the PG-34 asphalt mixture is better than the fracture resistance of the PG-40 mixtures, which is the opposite of what the PG system predicts.

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