The use of recycled waste elastic materials provides a cost-effective and environmentally friendly option for further modifying the performance of asphalt mixtures. Therefore, the effects of different proportions of (PMMA) polymethyl methacrylate derived from waste plastic material were evaluated using the Indirect Tensile Strength Test (ITST) of lab-prepared specimens. Since numerous methods of modifying the conventional asphalt binder are available, in this research, the virgin binder was modified with 1%, 2%, 3%, 4% and 5% PMMA for evaluating optimum performance proportions in terms of Marshall stability and ITST of asphalt mixtures. Furthermore, stiffness modulus tests were performed at frequency values of 1.2 Hz, 1.9 Hz, 3.9 Hz and 5 Hz. The effect of the loading rate from 10 MPa/s to 70 MPa/s was evaluated with an increment of 10 MPa/s for all proportions. Moreover, finite element modeling was performed using the data obtained from dynamic modulus tests with modified Burger's Logit model for evaluation of rutting progression. Results show improved performance of asphalt mixtures with the addition of PMMA, leading to variation in properties including penetration, softening point, Marshall stability and rutting resistance. It is recommended to use 5% PMMA for increased indirect tensile strength, Marshall stability, rutting and fatigue damage resistance.

In today's world, construction and infrastructure projects necessitate innovative solutions in environmental sustainability and materials engineering. In this context, research efforts to improve the properties of asphalt mixtures, reduce environmental impacts, and contribute to recycling hold great significance. This study focuses on modifying stone mastic asphalt mixtures with waste material derived from Polymethyl Methacrylate. Using Polymethyl Methacrylate as waste plastic material represents a significant step forward in recycling and sustainable material usage. In the study, Marshall specimens were obtained using Polymethyl Methacrylate in different proportions in bitumen and aggregate. The results of the Marshall specimens were evaluated to determine the usability and optimum ratios of Polymethyl Methacrylate. This study aims to evaluate the impact of Polymethyl Methacrylate on stone mastic asphalt mixtures as a support layer in railway tracks to help reduce noise and vibration. The results demonstrate that varying concentrations of Polymethyl Methacrylate in both aggregate and bitumen significantly alter the mechanical and thermal properties of the asphalt. For instance, incorporating 2.5% Polymethyl Methacrylate in the aggregate increased the VMA to 21, resulting in VFA values of 66. Furthermore, using Polymethyl Methacrylate in the aggregate increased the asphalt samples’ height, ranging from 69 to 72 mm. These findings underscore the effectiveness and feasibility of Polymethyl Methacrylate in sustainable asphalt projects. Following highway technical specifications, incorporating Polymethyl Methacrylate in specific proportions in stone mastic asphalt mixtures can enhance their performance, representing a significant step towards sustainable road construction. However, when the concentration of Polymethyl Methacrylate in the bitumen increased, the bitumen formed deteriorated. Therefore, using waste Polymethyl Methacrylate between 4% and 5% can be considered suitable for improving the properties of bitumen against sustainability and temperature concerns.

Skid resistance of a road pavement surface is the force developed when a tyre is prevented from rotating and slides along the pavement surface. This property comes from the combination of the macro- and micro-texture of pavement. The skid resistance of an asphalt pavement is an important parameter influencing driving safety on a road since there is a proven relationship between skid resistance and accident parameters. This paper deals with the measurement principle of pavement skid resistance (surface friction) including longitudinal and transverse friction. A high number of measuring devices of skid resistance are also introduced, highlighting their advantages and limitations. Moreover, the measurement policies in the European Union and in Hungary are outlined. Pavement surface texture is investigated, dealing with the levels of surface texture, the most common measuring techniques, the macro-texture features of asphalt types, as well as the Hungarian regulation in the field. As a related topic, the aggregate properties and their implication in the relevant Hungarian specification are introduced briefly as well. Some outcomes of the EU’s COST Action 354 on the development of unified European macro-roughness and skid resistance performance indicators and indices are also presented.

The recycling of reclaimed asphalt pavement is of significant economic and environmental benefits. In this case, however, the satisfactory performance of the final product needs scientific planning of the mixture and thorough quality control. Before its use, a number of tests must be performed to verify that the binder meets the relevant requirements and can be used in asphalt mixtures. The binder characteristics in the reclaimed asphalt pavement and the expected properties of the binder blend in the new asphalt mixture must be known. For its prediction and calculation, a European standard offers the calculation of the penetration or softening point of the binder blend in the mixture with reclaimed asphalt content. However, in some countries, the determination of paving grade bitumen types (categories) is based not on dynamic viscosity measured with DSR instrument, so other validated test and calculation methods are in force. A viscosity-based method has not yet been validated for paving grade bitumens standardized on a penetration basis, although this method is more advantageous in many aspects when monitoring daily production processes; it is much shorter and requires less material than measuring softening point or penetration. The article deals with the measurement of the dynamic viscosity of bitumen blends of asphalt mixtures made using reclaimed asphalts, determined with a dynamic shear rheometer at different frequencies (0.1–10.0 Hz sweep). Furthermore, the relationships between the different composition ratios of national paving grade bitumens classified on the bases of penetration level and bitumens from reclaimed asphalt pavement are examined.

The accurate determination of the rheological properties of road bitumen types is essential for the reliable prediction of long-term pavement behaviour. At 60 °C, dynamic viscosity is a key rheological parameter characterising the shear-dependent viscoelastic behaviour of bitumen in the temperature range relevant to in-service pavement loading. This study aims to compare different viscosity determination methods—approximations, capillary viscosity, Brookfield measurement and complex viscosity determined by a dynamic shear rheometer (DSR)—and to analyse their relationships with each other in order to find the best method for bitumen classification. Furthermore, the European and Australian bitumen classification standards are compared in terms of dynamic viscosity and penetration, according to which Australian bitumen types show more stable results, as the CV% is less than 10 percent. The study is based on the testing of Hungarian paving-grade bitumens (B50/70, B70/100) and Australian viscosity-graded bitumens (C170, C320), with the comparison of a total of 191 samples obtained from industrial production. The statistical evaluation of the results obtained with the different methods was based on Pearson correlation analysis and relative deviation analysis. The results indicate that the DSR measurement at 1.6 Hz shows the closest agreement with capillary viscosity, with a linear correlation coefficient of 0.95, and exhibits the strongest overall correlation with the other measurement approaches, whereas the Heukelom equation tends to overestimate the dynamic viscosity. The Brookfield method yielded higher viscosity values in all tests. The study highlights that the results of different measurement methods can only be compared under specific shear conditions, and a DSR-based approach can be more suitable for the introduction of a new European bitumen classification system.