Evaluation of the performance of rubber-modified bitumen

The paper discusses the effect of the amount and particle size of rubber on the properties of rubber-modified bitumen. Therefore, rubber-modified bitumen with rubber contents of 10, 15 and 20 % and a variation of the particle size from small (0.4 mm) to middle (0.8 mm) and up to big (1.0 mm) were prepared in laboratory by using a paving bitumen 50/70 as reference bitumen. Additionally, a polymer-modified bitumen (PmB 25/55-55), which is commonly used in asphalt wearing and binder courses, was involved in the investigations to verify the modification states. Different laboratory tests were conducted to evaluate the influence of the selected rubber particles. At first, the impact of the rubber modifications on conventional bitumen tests are presented. Furthermore, DSR tests were conducted to determine performance related bitumen properties. DSR results have also been used to determine the rutting susceptibility. In addition, the binders were rated to their fatigue damage resistance by applying repeated load cycles using the DSR test device as well. Following, the paper gives recommendations in terms of the use of rubber-modified binders for asphalt pavements