Requirements for the low-temperature cracking resistance of asphalt binders

This study investigates the rheological properties of 66 asphalt binders from diverse grades and sources, both fresh and laboratory-aged, in the low-temperature range. For this purpose, the Dynamic Shear Rheometer (DSR) with 4 mm parallel-plate geometry and the stress relaxation test at a temperature of -20 degrees C is used. This method effectively evaluates binders' resistance to low-temperature cracking through stress relaxation metrics. From the test results, specific requirement values for different binder types are proposed which may find practical application in tenders. The validation was carried out by a comprehensive sampling strategy of both mixing plants and pavement cores over multiple test sections, whereby a high suitability and applicability of the requirement values was determined. The inter-laboratory repeatability and reproducibility of the method were robust across different instrument manufacturers and personnel.