The consistency of bitumen as a leading indicator is usually evaluated by the depth of a needle penetration. This characteristic shows the extent (measure) of bitumen resistance to penetration of a standardised needle under specified load and time. Each penetration value corresponds to specific shear rate time function with its own average shear rate. Therefore, the comparison of consistency by penetration is not sufficiently informative. To predict the strength of asphalt concrete in the field, it is necessary to determine the strength of the binder at a given temperature and strain rate. At temperatures above 0°C, cohesion (maximal shear resistance) of a bituminous film at a plane-parallel shear can be used as a measure of strength. In this paper, existing types of cohesion-meters are considered; a cohesion-meter adopted for the research is described in which a shear of a bituminous film with a thickness of 200 µm is carried out at a shear rate of 1 s⁻¹ and at a temperature of 25°C. The dependencies of cohesion on the temperature of bitumen of different types of structure and of the sol-gel type bitumen at different shear rates are presented. The dependence of cohesion on the penetration of bitumen obtained by oxidation and vacuum distillation is considered, the effect of polymer and warm-mix additive on cohesion is shown. The relationship between shear strength and loss modulus values of bitumen at the equivalence of shear rate and angular frequency is established, as well as the relationship between cohesion and shear resistance that is determined in a rotational viscometer. The suggestion was made to possibly use the shear resistance determined at a temperature of 60°C and a fixed shear rate (1 s⁻¹) as an indicator of cohesion for predicting the rut resistance and shear strength of asphalt concrete.

The growing emphasis on sustainable road construction has stimulated interest in environmentally friendly bitumen modifiers. This study presents the development of biodegradable adhesion promoters synthesized via the amidation of renewable raw materials (rapeseed oil and higher fatty acids) with polyethylene polyamine. The main objective was to improve bitumen–aggregate adhesion while maintaining the essential physico-mechanical and rheological properties of the bitumen. The synthesized bio-based adhesion promoters were incorporated into penetration-grade bitumen at a dosage of 0.4 wt.%. Physico-mechanical testing confirmed that their inclusion does not significantly affect the fundamental properties of the bitumen, while substantially enhancing adhesion to both glass and mineral aggregates. Rheological analysis showed that the rapeseed oil-based adhesion promoter had minimal influence on viscoelastic behavior. In contrast, the fatty acid-based promoter increased the rutting resistance parameter (|G*|/sinδ) and decreased the phase angle (δ), indicating improved resistance to permanent deformation. FTIR spectroscopy further revealed that the fatty acid-based adhesion promoter significantly reduced the formation of carbonyl groups during short-term aging, suggesting a retardation in oxidative aging and potential rejuvenating effects. In conclusion, the proposed bio-based adhesion promoters, derived from renewable sources and fully biodegradable, represent a promising solution for enhancing bitumen performance and supporting the durability and sustainability of asphalt pavements.

Рассмотрено функционирование системы обеспечения безопасности труда на угледобывающих предприятиях с использованием критерия надежности. Представлены закономерности производственного травматизма и структурно-функциональной деформации системы обеспечения безопасности труда. Обозначены возможности повышения надежности ее функционирования. Предложены взаимодополняющие принципы организации этой системы, необходимые для повышения надежности ее функционирования, что, в свою очередь, позволит устойчиво снижать травматизм на угледобывающих...

The influence of cationic adhesion promoters of the amine type on the properties of petroleum road bitumens is studied in the article. The impact of the selected adhesion promoters on standard quality indicators of bitumen, such as penetration, softening point, and penetration index, is evaluated. The effect of the promoters on bitumen adhesion is assessed using the bottle rolling method and the glass surface adhesion method. The thermal stability of the promoters was determined by evaluating the reduction in bitumen adhesion after short-term ageing. The influence of adhesion promoters on the bitumen contact angle is also investigated. The following set of indicators is proposed for the evaluation of the effectiveness and thermal stability of adhesion promoters.

Introduction. The performance and durability of asphalt pavements are majorly conditioned by the quality of the bituminous binders. One of the main disadvantages of asphalt pavements is the permanent change in their properties in time due to the aging of the binder. Various laboratory methods of aging are used to predict the intensity of changes in the properties of bituminous binders that occur during the asphalt mixing at plants and the lifetime of asphalt concrete in the pavement. Problem Statement. In Ukraine, with the implementation of European principles of standardization and the transition to harmonized European standards, there is a gradual replacement of the aging method ГОСТ 18180, which has long been used in the domestic road industry, with the world-accepted RTFOT aging method. Due to the different conditions set in these methods of aging, the question of the impact of differences in aging regimes on the properties of bituminous binders, the possibility of comparing the results obtained by these two methods and the interchangeability of methods is topical. Purpose. The aim of the work is to obtain the influence of the methods of aging adopted in the road industry of Ukraine on the change of properties of road viscous bitumens and bituminous binders, modified with various additives. Materials and methods. Viscous bitumens and bituminous binders modified with various additives (adhesive additives, polymers, structuring additives) used in the domestic road industry are used as objects of research. For methods of aging the domestic method ГОСТ 18180 (for a long time this method was the only one in Ukraine used for estimation of change of properties of bituminous binders under the influence of technological temperatures and which, under test conditions, is close to the standardized method TFOT), as well as the world’s widespread RTFOT method of aging are used. Results. Based on the obtained experimental data, it is found that aging by the ГОСТ 18180 method has a slightly greater effect on the change of properties than after aging by the RTFOT method. The least sensitive indicator of aging conditions is the breaking point temperature — the difference between the values of this indicator after aging by different methods is within the convergence of the method. The conditions of the aging method have the greatest effect on the quality of bitumens modified with adhesives. The relatively short heating time of binders in accordance with the conditions of the RTFOT aging method leads to less change in the adhesion of binders to the glass surface, which may contribute to misleading in thermal stability of adhesives. Conclusions. When revising the domestic standards for technical conditions for bituminous binders, which provide for the replacement of the aging method according to GOST 18180 by the RTFOT method and setting of limits for changing the standard quality of binders after aging, should take into account the slightly lower aging intensity of RTFOT binders. This is especially true for the adhesion requirements of bitumens modified with adhesives.