COMPARISON OF TECHNOLOGIES FOR PRODUCING ROAD BITUMEN FROM HIGH-RESIN RAW MATERIALS

Road bitumen obtaining from high-resin raw materials is always a difficult task. That is why, the aim of this work is to determine the technology for obtaining various grades of road bitumen and modified bitumen from high-resin tar. The research was carried out in three stages. In the first stage, the possibility of obtaining oxidized petroleum road bitumen in accordance with the requirements of State Standard 33133-2015 for the BND 70/100 and BND 50/70 grades was investigated. It was found that the obtained bitumen samples do not meet the requirements of State Standard in terms of such a basic indicator as penetration at 25 °С, and also had low values of extensibility at 25 °С. When conducting the oxidation process of modified tar with vacuum gas oil, it was found that with an increase in the content of vacuum gas oil in tar, the depth of penetration of the bitumen needle at 25 °С increased, and the extensibility was extreme. In addition, when oxidizing modified tar, the yield of blow-off (black diesel) increased. It has been shown that the oxidation process of modified tar can be used to obtain BND 70/100 bitumen with a vacuum gas oil content of more than 12 % by mass. At the second stage, oxidized bitums with softening points of 56 °С, 61 °С, and 67 °С and tar were used to study the production process of petroleum road bitums using the oxidation-compounding technology. This technology allows for the regulation of the raw material composition, process parameters, and the production of a wide range of bitums. The analysis of the research results showed that when using deep-oxidized bitumen with a softening point of 58 °С to 67 °С, it is possible to obtain bitumen grades BND 50/70 and BND 70/100. For BND 70/10 bitumen, the tar content in the deep-oxidized bitumen should be between 43 % by weight and 57 % by weight, and for BND 50/70 bitumen, it should be between 32 % by weight and 46 % by weight. At the third stage, the technology for producing modified bitums consisted of compounding deep-oxidized bitumen with modified vacuum gas oil in an amount of 15% by weight. The bitums were obtained by compounding deep-oxidized bitums with softening points of 56 °С, 61 °С, and 67 °С with modified tar to softening points of 51 °С and 47 °С. Bitums obtained using this technology had increased penetration values at 25 °С and 0 °С, good low-temperature properties, and satisfactory stability to aging processes. It was found that bitums with softening temperatures ranging from 56 °С to 67 °С can be used as deeply oxidized bitums using the oxidation-compounding technology. The content of vacuum gas oil in the tar for compounding should be about 15 % by mass. For BND 70/100 bitumen, the modified tar content in the deep-oxidized bitumen should be in the range of 40 % by mass to 48 % by mass, and for BND 50/70 bitumen, it should be in the range of 30 % by mass to 37 % by mass. Thus, the compounding method, with the appropriate selection of components, has made it possible to obtain road bitumen with a specified level of basic characteristics that meet the requirements of the technological standard.