Petroleum bitumen and polymer-bitumen binders: Current state and Russian specifics. Review.

The paper deals with the research and practical use of petroleum bitumens and bitumen-based modified binders in road construction in Russia compared to the advanced global research. It is shown that unmodified petroleum bitumens are used in the construction and repair of regional and local roads in Russia. Moreover, in Russia, oxidized bitumens are widely used, the quality of which is significantly inferior to the residual bitumens accepted for use in developed countries. The materials used for bitumen modification in Russia and abroad are considered, the most widely used thermoelastoplasts, thermoplastics, and natural and synthetic rubbers including. The issues of using sulfur and its derivatives as cross-linking agents are discussed. Reactive substances, as well as the functionalization of the modifiers themselves, i.e., the directed use of functional groups that provide missing bonds in the interaction are covered. The studies on nanoscale effect in the interaction of bitumen components with natural or synthesized nanomaterials are presented. Currently, an increasing number of researchers, both in Russia and abroad, are trying to find ways to improve the quality characteristics of modified bitumens using waste, while solving both environmental and economic problems. Although there has been marked progress in such developments, they are still difficult to compete with specially designed and manufactured modifiers. This progress is evident in the use of so-called hybrid or mixed modifiers, the components of which are selected for improving specific properties. There is considerable interest in the use of crumb rubber from worn-out tires as a potentially suitable component for making bitumen elastic and reducing the brittleness temperature. In Russia, there are noteworthy developments in this area that have been industrially tested. An interesting method is the high-temperature shear grinding of rubber crumbs on ultra-high-pressure devices, at which the specific surface area of the particles is disproportionately large, compared to the known methods. This provides an accelerated interaction of particles with bitumen forming mesh structures at the dry method of introducing crumb directly into bitumen-concrete mixture. The paper describes the main types of equipment for bitumen modification. Currently, the road industry in Russia is undergoing a conceptual transition to the new generation of standards. [ABSTRACT FROM AUTHOR]