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.

ЗАСТОСУВАННЯ МЕТОДУ ВИБОРУ МАРКИ БІТУМНОГО В'ЯЖУЧОГО, ЗГІДНО З СИСТЕМОЮ SUPERPAVE, В УМОВАХ УКРАЇНИ

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.