The authors present the unsolved issue of the contextual design of urban intersections (UI) from the point of view of traffic noise emissions around residential buildings in the Slovak context. Noise barriers are very rarely used in urban areas, due to such reasons as lack of space for their installation, traffic safety (view at intersections), architectural factors, as well as the fact that they represent a barrier for pedestrians and cyclists. The use of low-noise asphalt pavements is limited in urban areas primarily due to the high cost of production and maintenance of these covers, their limited durability in a colder climate, and lower efficiency compared to the roads outside urban areas. From this aspect of urban intersection design, the authors focused on the identification of individual factors associated with the significant reduction (2–8 dB) of traffic noise induced by the reconstruction of non-signalized urban intersections into roundabouts. The authors draw attention to the fact that both new surfaces of intersection branches and the change in traffic processes contribute to the aforementioned reduction. This finding was obtained by comparing direct measurements of noise levels and the results of their predicted values using validated 3D models in the CadnaA program. Noise emissions were measured by a noise analyzer (NOR-1210), and traffic noise emissions were predicted by the “Nouvelle Méthode de Prévision du Bruit” methodology (NMPB-1996). Based on the analysis of the measured and predicted traffic noise levels, the authors objectivized the share of reduction in traffic processes in the 2–3 dB range. The authors objectified the share of traffic noise reduction due to the change in traffic processes as being in the 2.2–3.3 dB range. The presented research results could contribute to a quantifiable reduction in the noise load in the external environment of residential buildings using the contextual design of intersections.

Asphalt mixtures have a dominant position in road construction in most countries. The choice of asphalt mixture type and surface depends mainly on the traffic loading and climatic conditions. The stiffness of asphalt mixture is one of important parameters that determines how road pavement performs and what pavement response to traffic loading. The stiffness modulus of the asphalt mixture changes during its service life, it tends to increase. During this process the mixtures in pavement age and degrade. Aging of asphalt mixtures has a significant effect on changes in the properties of individual mixtures. Presented research was focused on monitoring the change in the stiffness modulus of two asphalt mixtures AC11 50/70 and AC11 PMB 45/80-75 by the effect of aging. The asphalt mixtures have been exposed to the effects of short-term and long-term ageing by the conditioning of loose mixture method. After aging of the asphalt mixtures, the stiffness modulus of compacted asphalt mixture samples was measured. The stiffness modulus was determined using the IT-CY method at temperature of 10 °C, 20 °C and 30 °C and showed an increase after exposure of the mixture to short-term and long-term aging.

The quality of bitumen is standardized by conventional tests. With the development of new techniques, rotational and oscillatory measuring systems are applied to evaluate bitumen under defined geometric, temperature, frequency, stress, and strain conditions that correspond to loads during asphalt production and service. Several studies have focused on determining the effect of composition on bitumen properties at service temperatures. However, there is a lack of information related to the effect of composition on viscosity at higher temperatures, which influences production processes. The different types of bitumen, samples of 50/70, 35/50, 45/80-75, and 25/55-60 bitumen, had different viscosity values in intervals corresponding to a confidence level of 95%. The viscosity–temperature relationship in temperature range of 120 to 180 °C was observed in values of 3.87 and 3.70 for unmodified bitumen and 3.09 and 3.22 for modified bitumen. The effect of differences in SARA fractions content on the variation in viscosity using regression analysis showed the importance of asphaltenes (direct correlation) and aromates (negative correlation) contents for 50/70 bitumen with a coefficient of linear regression above 0.7. In comparison, the strong effect of saturates and asphaltenes (negative correlation) and resins was identified for 45/80-75 bitumen samples with correlation of 0.5 to 0.7.

The complex factors during the asphalt production process and subsequent traffic loading, climatic and weather conditions lead to a decrease in durability of asphalt thereby reducing pavement surface service life. The research focused on the effect of thermo-oxidative aging (short and long term), ultraviolet radiation and water on stiffness and indirect tensile strength of asphalt mixtures with 50/70 and PMB45/80-75 bitumen. The stiffness modulus at different temperatures (10, 20 and 30 °C) using the indirect tension method and indirect tensile strength have been evaluated in relation to the degree of aging. The experimental analysis showed a significant increase in the stiffness of polymer-modified asphalt with increasing aging intensity. Exposure to ultraviolet radiation adds to an increase of 35 to 40% in stiffness for unaged PMB asphalt and 12 to 17% for short-term aged mixtures. Accelerated water conditioning reduced the indirect tensile strength of asphalt by an average of 7 to 8%, significant in long-term aged samples using the loose mixture method (9 to 17%). The indirect tensile strengths for dry and wet conditioning showed greater changes due to the degree of aging. An understanding of the changes in asphalt properties during design allows for predicting asphalt surface behaviour after a period of use.

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