Nowadays in the world, due to the constant desire for recycling, many countries are considering the use of recycled plastics on roads. Modification of bitumen for roads in Kazakhstan is considered one of the most suitable and popular approaches. This paper presents the results of research on the modification of bitumen by recycled plastics from waste materials. The paper describes the details of the use of plastic waste as bitumen modifiers, with a specific focus on recycled plastics and how they can potentially be used to enhance bitumen performance and the road durability. The main physical and mechanical characteristics of the modified bitumen were determined after routine tests, penetration and plasticity, softening temperature, brittleness temperature on Fraas and microscopic analysis. The morphology of the modified bitumen was studied using scanning electron microscopy. The results confirm that the modified bitumen complies with the requirements for polymer-bitumen binder of Kazakhstani standards and is suitable for the production of modified bitumen by its physical and chemical characteristics.

The article presents the results of research on the production of polymer-bitumen binder (PBB) based on mixtures of non-oxidized and oxidized petroleum products, namely high-viscosity tar, darkened vacuum distillate, and oxidized petroleum bitumen 70/100, obtained at technological installations of Limited Liability Partnership (LLP) “JV Caspi Bitum’’ and styrene-butadiene-styrene (SBS) block copolymer brand L 30-01A modifier in the presence of a stabilizer. The results obtained show that the introduction of the SBS modifier in the presence of a sulfur stabilizer improves the performance characteristics of PBB, such as elasticity, ductility, softening temperature, penetration, and brittleness temperature.

According to scientific research from different countries, crumb rubber obtained from end-of-life tires (ELT) during processing can improve the properties of the asphalt mixture, thereby extending the service life of the road surface. This paper presents the modification of bitumen with industrial rubber waste. The modification of bitumen for roads is considered one of the most suitable and popular approaches. This research paper describes the details of using different types of crumb rubber as bitumen modifiers. The modified bitumen’s main physical and mechanical characteristics were determined after conventional tests: penetration and ductility, softening point, and Fraas brittleness point. In order to obtain a rubber–asphalt concrete mixture with improved performance characteristics, the viscoelastic and rheological properties of rubber–bitumen binders and their comparison with polymer–bitumen binders were also studied. The research results show that with increasing temperature, the values of viscosity, shear stress and complex shear modulus of all studied bitumen systems decrease, the values of the phase shift angle increase, and the size of the rubber particles has a greater influence on the properties of bitumen systems.

The use of rubber-polymer composites ELTC (End of Life Tire Compound) for bitumen modification was investigated. ELTC contains not only devulcanized rubber from used car tires, but also used plastics (polymers) such as polyethylene (PE) and polypropylene (PP). ELTC is obtained using the method of rubber devulcanization using a selective catalyst that allows selectively decomposing sulfide bonds at relatively low temperatures, while preserving most of the macromolecular chains. The characteristics of the asphalt binder improved after the modification of ELTC. After modification, the base asphalt binder became more homogeneous, and the thermal stability of the base asphalt binder increased. ELTC is evenly distributed, the compatibility between the components of the modified asphalt binder is good, which proves the uniformity of the modified asphalt binders. The results show that all ELTC formulations improve the softening temperature and increase their resistance to plastic deformation in the summer.

This study investigates the modification of bitumen using mechanochemically devulcanized crumb rubber. The objective of this research is to enhance the performance characteristics of bituminous binders while addressing the inherent limitations associated with conventional crumb rubber (CCR), such as insufficient dispersion, elevated viscosity, and phase instability. Preliminary chemical activation of the crumb rubber was performed using a planetary ball mill, followed by thermomechanical devulcanization on a two-roll open mixing mill. Structural features of the devulcanized crumb rubber were analyzed using infrared spectroscopy, which confirmed the breakdown of S–S bonds. This study presents a comparative analysis of the performance characteristics of rubber–bitumen binders produced using both conventional rubber crumb (CRC) and devulcanized rubber crumb (DRC). The use of DCR, obtained mechanochemically from rubber waste, improved penetration, Fraass breaking point and the ring and ball softening point on average at high concentrations (20; 25% crumb rubber) compared to conventional crumb rubber by 33%, 66% and 2.4%, respectively. Optical microscopy revealed the formation of a uniform mesh-like rubber structure within the bitumen matrix, which contributes to enhanced performance characteristics of the modified binder and improved mechanical strength of the material. The key contribution of this work lies in the development and experimental validation of an efficient approach to deep devulcanization of crumb rubber via mechanochemical activation using readily available nitrogen-containing reagents. Furthermore, the study establishes a direct correlation between the degree of devulcanization, the dispersion quality of rubber particles within the bitumen matrix, and the resultant performance characteristics of the modified binder.

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.