This study examines the influence of virgin polyethylene (vPE), recycled polyethylene (rPE), and Aerosil (A) on the performance of bitumen binders modified with partially devulcanized rubber (DVR). The experimental program included morphology analysis, determination of devulcanization degree, dynamic viscosity measurements, shear stress–shear rate analysis, load–displacement (F–Δl) testing, storage-stability evaluation, ring and ball softening point (R&B), penetration (P), and elastic recovery (ER) testing. The results show that DVR-rPE-modified bitumen binders exhibit 20–35% higher viscosity and up to 25% greater elongation at the break compared to DVR-vPE-modified bitumen systems, indicating more effective interaction with the bitumen matrix. The incorporation of Aerosil increased viscosity ca. 1.5–2 times for DVR-rPE and DVR-vPE-modified systems, respectively. Meanwhile, top and bottom differences in R&B decreased by a factor of 1.6–5 for DVR-rPE and DVR-vPE-containing composites, respectively, demonstrating significant enhancement in structural stability during storage. Mechanical testing further revealed that DVR-rPE + A binders absorbed 10–20% more deformation energy and consistently maintained ER values above 70–80%, corresponding to a higher elastic recovery grade at 25 °C. Overall, the DVR-rPE + A system provided the most balanced improvements in rheological, mechanical, and thermal properties, confirming its potential for use in high-performance, thermally stable, and environmentally sustainable bituminous materials for pavement applications.

The growing depletion of conventional crude oil resources has intensified interest in unconventional hydrocarbon feedstocks such as oil sands and natural bitumen. This study presents an integrated recovery and upgrading of oil sands bitumen from the Karasyaz–Taspas deposit: process development and product characterization. Experimental investigations included bitumen extraction, atmospheric and vacuum distillation, and comprehensive physicochemical characterization (density, viscosity, elemental composition, and SARA fractions). The extraction process achieved a recovery efficiency of up to 98%, demonstrating the effectiveness of the applied approach under mild temperature conditions. The obtained results indicate that the bitumen is characterized by a balanced fractional composition with a significant yield of middle distillates and oil fractions, which makes it a promising feedstock for the production of fuels, base oils, and bituminous materials. A process flow scheme integrating extraction, fractionation, and upgrading stages is proposed and discussed from a technological perspective. The study provides a practical assessment of the applicability of nitrite-based extraction systems for oil sands processing and highlights the potential for implementing modular processing units under field conditions. The findings contribute to the development of resource-efficient approaches for the utilization of Kazakhstan’s unconventional hydrocarbon resources.

This article explores the use of rubber–polymer composites for bitumen modification. The hybrid modifier consists not only of devulcanized rubber derived from used car tires but also includes post-consumer plastics such as polyethylene (PE) and polypropylene (PP). The characteristics of the asphalt binder improved after modification with the hybrid additive. This study examined the potential of enhancing the physico-mechanical properties of road bitumen using hybrid modifiers based on waste materials. Experimental results showed that all hybrid modifier compositions (based on rubber and polyethylene/polypropylene) significantly increased the softening point of bitumen and improved its thermal stability. In particular, the addition of 20–30% polyethylene raised the softening point to 80 °C, which is 20 °C higher than that of unmodified 70/100 grade bitumen. It was found that an increase in the polymer content led to a systematic rise in softening temperature. Moreover, a sample containing 20% of a modifier with 10% polypropylene achieved an elastic recovery of 54–55%, meeting the minimum standard requirement in Kazakhstan (≥50%). Needle penetration test results confirmed the increased hardness of the bitumen, with the value dropping from 90.8 to 26.6 at 25 °C. Overall, the study demonstrated that the use of hybrid modifiers based on waste polymers and rubber can produce environmentally sustainable and high-quality road bitumen. The findings confirm that such modifiers significantly enhance the high-temperature stability and elasticity of bitumen, expanding the potential for effective and eco-friendly reuse of rubber and plastic waste in road construction.

As conventional hydrocarbon resources become depleted, there is growing interest in developing unconventional sources of raw materials, such as natural bitumen (NB) and oil-bituminous rocks (OBR). This article presents the results of comprehensive scientific research into the physical and chemical properties and composition of the natural bitumen found in the Karasyaz-Taspas field in Mangistau, Kazakhstan, and the development of effective technological solutions for its processing. A comprehensive analysis of the elemental, group and fractional composition of the natural bitumen was carried out. On the basis of this analysis, the technological value of the natural bitumen as a raw material for obtaining a wide range of target products, such as fuel distillates, base oils and construction bitumen, was established. Based on experimental data, the effectiveness of extracting natural bitumen using a nitrite composition has been demonstrated, as has the potential of distillate and residual products. Distillate fractions were found to be suitable for use as components of motor fuels and lubricants, while residual products were found to be suitable for the production of road and construction bitumen. Technological solutions for the complex processing of natural bitumen have been developed and put forward. The results obtained confirm the potential for the integrated development of Kazakhstan’s oil-bituminous rock reserves as a valuable source of hydrocarbons, opening up opportunities to expand the raw material base and promote the development of the Republic of Kazakhstan’s petrochemical industry.

In this paper, the use of rubber-polymer composites ELTC (End of Life Tire Compound) for modification of BND 70/100 bitumen was investigated. ELTC contains not only devulcanized rubber from used automobile tires, but also used plastics (polymers), such as polyethylene (PE) and polypropylene (PP). ELTC was obtained by applying the method of rubber devulcanization using a selective catalyst, which allows selective decomposition of sulfide bonds at relatively low temperatures, while preserving most of the macromolecular chains. The characteristics of the asphalt binder were improved after modification by ELTC. After modification, the base asphalt binder became more uniform, and the thermal stability of the base asphalt binder increased. ELTC is uniformly distributed, the compatibility between the components of the modified asphalt binder is good, which proves the homogeneity of the modified asphalt binders. The results show that all ELTC formulations improve their softening point and increase their resistance to plastic deformation in summer. The results of the needle penetration test at 25°C show that the addition of modifiers reduces the penetration value. This means that at this test temperature, the modified bitumen becomes harder compared to the unmodified bitumen.

The accumulation of end-of-life tires and post-consumer polyolefin waste is a growing environmental burden, and their reuse as bitumen modifiers offers a sustainable, large-volume outlet in road construction. This study investigated paving-grade bitumen modified with four pre-compounded, partially devulcanized rubber (DVR)-recycled-polymer composites, differing in polymer type and, for two of the systems, in styrene–butadiene–styrene (SBS) chain architecture (linear or radial), added at 9–15 wt.%. The modified binders were characterized by penetration, softening point, elastic recovery, force ductility, low-temperature brittleness, and dynamic shear rheometry (DSR), together with FTIR, TGA, and fluorescence microscopy. All four composites improved binder stiffness, elasticity, and high-temperature rheology relative to the unmodified bitumen, with the two SBS-containing systems performing best overall. At the highest modifier content, the best-performing composite roughly halved the penetration and raised both the softening point and the higher critical temperature or rutting parameter by approximately 28–30 °C, while also markedly improving elastic recovery and low-temperature flexibility relative to the base bitumen. These findings indicate that SBS-containing devulcanized-rubber/recycled-polymer composites are promising sustainable modifiers for producing high-performance bituminous binders from waste-derived materials.