, Professor, Civil, Environmental and Geo-Engineering
Gene Skok, Former University Researcher, Civil, Environmental and Geo-Engineering
The objective of this study was to create an inventory of the rheological properties of certified asphalt binders used in Minnesota. A literature search was performed to identify existing databases as well as more complex test methods for asphalt binder characterization that have been proposed recently. Nine different asphalt binders were studied. The binders were aged according to standard aging procedures and subject to a number of tests. The Bending Beam Rheometer (BBR) and Direct Tension Tester (DTT) were used together to determine the critical cracking temperature of the binders at low temperatures. The Dynamic Shear Rheometer (DSR) was used to test frequency sweeps (to generate master curves and to calculate zero shear viscosity), strain sweeps (to verify linear viscoelasticity), repeated creep (to measure the permanent strain accumulated after 100 cycles), and fatigue tests (to test for fatigue cracking at intermediate temperatures). A database was created in Microsoft Access , which is easy to use and readily available to most users. Test results, along with some model parameters, were stored in tables inside the database. As more test results become available, the can easily be imported to the database.