High-temperature rheological properties of asphalt binders with polymeric, warm-mix, and rubber particulate additives

High-temperature rheological properties of asphalt binders are important in asphalt mixture production and compaction. In this study, the high-temperature rheological properties of asphalt binders with polymeric, warm-mix, and rubber particulate additives were examined at different temperatures, shear rates, and shear modes. Most of the tests were conducted using a concentric cylinder measuring system with a dynamic shear rheometer. The test results provide a full picture of the rheological behaviors of those binders at or approaching the mixing and compaction temperatures. Test results indicate that shear rate dependency of modified asphalt binders at high temperatures is generally not significant and is related to binder type. The shear thinning behavior is more noticeable for binders with particulate modifiers than for those with styrene-butadiene-styrene (SBS) polymers. The apparent shear thinning behavior shown at high shear rates at relatively low temperatures may be attributed to discontinuity developed during the test. The test results also suggest that there are interactive effects between warm-mix additive type, binder type, and test conditions (temperature and shear rate). Hence, the effects of warm-mix additives may need to be considered at different combinations of temperatures and shear rates. The complex and rotational shear viscosities were found to be comparable at lower test frequencies (or shear rates), but not at higher ones, and the responses of different binders to shear modes were found to be different. Although this study does not aim to develop new criteria for mixing and compaction temperatures for asphalt mixtures with modified binders, the insights gained are expected to contribute to the body of knowledge in this area.