| Popis: |
The heavy traffic combined with the adverse weather and climate factors which are characteristic for most of the year, makes high demands for asphalt concrete. The quality of asphalt concrete is largely determined by the properties of bitumen which plays the role of a binder which provides the formation of a monolithic composite road-building material from separate mineral grains. Compound bitumen obtained by mixing the peroxidized bitumen with tar have the best ratio of all physico-chemical indicators, it is also possible the option to compound residual bitumen with oxidized. Oxidized bitumen obtained by the oxidation of tar or a mixture of tar with other petroleum products is characterized by low cohesive strength, poor adhesion and considerable aging. The use of natural bitumen of gilsonite type is the most common method to improve the properties of bitumen. When introducing into the bitumen of this natural bitumen, its penetration at a temperature of 25° C is reduced, as well as the softening point is increased. In fact, the nature of the change in the properties of bitumen during introduction of natural bitumen is the same as during its oxidation. That is, natural bitumen can be used to produce road bitumen by compounding it with tar. This paper presents the results of bitumen research obtained by combining tar with natural bitumen of gilsonite type. The production of bitumen by combining tar with natural bitumen of gilsonite type allows obtaining different grades of road bitumen by changing the content of natural bitumen. Bitumen obtained by this technology is more heat- and crack-resistant, have high adhesion to the aggregates and are not subjected to the technological aging. This bitumen has a higher softening point and a lower Fraass breaking point and therefore a higher plasticity interval. Keywords: bitumen, production, equiviscous temperatures, natural bitumen, mixing. |
