New Technique for Measuring Low-Temperature Properties of Asphalt Binders with Small Amounts of Material

A new technique, which uses 4-mm parallel plates on a dynamic shear rheometer (DSR) with machine compliance corrections, was developed to measure low-temperature properties of asphalts. Good results have been achieved at test temperatures as low as −40°C. The test method requires only about 25 mg of material instead of 15 g for the bending beam rheometer (BBR). Also, no specimen premolding is needed, and a relatively low temperature (60°C to 70°C) is required to load the samples into the measuring system. The key to the new technique is correction for errors due to machine compliance. Two types of machine compliance correction were applied to the dynamic frequency sweep data in this work. The following areas were investigated: effects of machine compliance on the measured low-temperature properties, reproducibility of data, consistency among data collected on different sizes of plates after machine compliance corrections, and comparison between the corrected data from DSR and converted BBR data. Results show that this new technique is a reliable, rapid, and simple to perform test method, allowing for analysis of low-temperature properties of asphalt binder as well as extracted samples from pavements and other materials such as cold-mix asphalt and emulsion residue that require low-temperature operations and small samples.