PERFORMANCE OF ASPHALT MIXTURES WITH A NEW TYPE OF RUBBER MODIFIED BITUMEN

The rubber modified bitumen 45/80-55 (RMB 45/80-55) product has been used in Hungary as bituminous binder for asphalt mix production since 2013. It is a new kind of rubber bitumen manufactured using patented technology. Over the past 8 years, it has been used to construct or renovate more than 100 asphalt road sections. Originally RMB 45/80-55 was used to replace paving grade bitumen 50/70 in some road construction projects. However, asphalt laboratory results and road construction experience showed that its quality can also achieve or in terms of some parameters exceed that of asphalt mixtures manufactured with polymer modified bitumen 25/55-65 (PMB 25/55-65). Primarily, its excellent resistance to low temperatures and fatigue are outstanding, in this respect; it surpasses the results of asphalts made with polymer-modified bitumen. Its favourable fatigue resistance compensates for its lower stiffness; therefore, favourable results were obtained in the case of track structure design too in comparison with PMB. Considering the road construction benefits of this new type of rubber bitumen, as well as the support of the environmentally friendly recovery of waste tyres and fitting into a circular economy, a wider spread of the RMB product is realistically expected in the future.