Aging peculiarities of paving bitumen, which was obtained by different ways, have been studied. Oxidized and residual bitumen produced from oils of Ukrainian deposits were used and the changes in the main characteristics of bitumen after 5 and 10 h of aging in a thin film at the temperature of 436 K have been determined and the processes occurred during the aging have been studied. Using infrared spectroscopy, the changes in the structural composition of the binder during aging have been analyzed.
The effects of the technological process of aging of bitumen obtained from the residues from processing of Ukrainian crude oil on the bitumen’s operational characteristics, structural-group composition, and thermal stability have been studied. The aging of bitumen with a thickness of 2 mm has been conducted under laboratory conditions at a temperature of 1630C for 5 and 10 h. Two types of bitumen, oxidized bitumen BND 60/90 and distillation bitumen BD 130/200, have been examined. It has been found that the bitumen quality worsens due to the technological process of aging, e.g. the bitumen hardness and refractoriness increase whereas the elasticity and frost resistance decrease. It has also been shown that, because of the technological process of aging, the content of resins in the bitumen decreases, the content of asphaltenes increases, and the content of oil components does not change significantly. The structural type of the oxidized bitumen changes thereat from a "sol–gel" type to a "gel" type. For the distillation bitumen, the structural type does not change. The derivatographic analysis has revealed that the bitumen thermal stability increases due to the technological process of aging. The reason for this is a decrease in the content of paraffinic ingredients in the bitumen along with the bitumen structure compaction due to the aging.
Three samples of bituminous material with different softening temperatures of 321, 332, and 356.4 K were obtained by the method of chemical modification of tar with formaldehyde using sulfuric acid as a catalyst. The determination of the group hydrocarbon composition was carried out for the raw materials of the modification process (tar) and the resulting bitumens. An FTIR study of the obtained groups of hydrocarbons (oil, resins, and asphaltenes) was also carried out. The structural transfor¬mations were investigated and a possible chemistry of the tar modification process with formaldehyde was proposed.
Despite to the significant advantages of asphalt concrete coating in comparison with other types of coatings, such as high mechanical strength and roughness; low rigidity of the coating; high ability to absorb vibrations, etc., there are also significant disadvantages of asphalt concrete. Among the main ones is the short term of use, which manifests itself in the breaking and destruction of the roadway after several changes of seasons. The reason for this phenomenon is the complex effect of natural and mechanical factors, which finally lead to different types of chemical and structural changes in the binder of the asphalt, which also called aging of bitumen.The aging process of the binder begins long before the bitumen gets into the asphalt. Since the main part of the Ukrainian binders is obtained by the oxidation of tar, the conditions of the oxidation process play an important role for further transformation. In addition, there are internal irreversible reactions in bitumen, which occur under the influence of oxygen, heat, low temperatures and light.To evaluate the intensity of bitumen aging in the coating, we investigated the change of bitumen properties before and after warming, which allows simulate the thermal oxidation of bitumen -in a thin layer of binder (2 mm) at 163°C for 5 or 10 hours. As the simple we used Ukrainian bitumen of the BND 60/90.Thereafter, a comparison of baseline data and indexes, determined after the aging process was performed to evaluate changes due to the aging of bitumen. Among the main ones are weight loss and softening temperature change, needle penetration depth (penetration), brittleness temperature and elongation (ductility), determined by standard methods. Structural-group analysis, infrared spectroscopy of the original bitumen and aged samples were made for control changes occurring in the aging process.According to the obtained results, as a consequence of aging in the bitumen, penetration and ductility are significantly reduced, which is explained by the loss of bitumen plasticity, which causes a decrease in the number of olive components and an increase in the content of asphaltenes. An increase in the softening temperature is also a confirmation of this phenomenon.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.