PREREQUISITES FOR THE REMOVAL OF RESTRICTIONS ON THE MOVEMENT OF FREIGHT VEHICLES IN HIGH AIR TEMPERATURES

Abstract

Introduction. Currently, in Ukraine, there are restrictions on the traffic of vehicles with an actual weight of more than 24 tons and an axle loading of 7 tons during the day at an air temperature above 28 °C, except for vehicles carrying dangerous, perishable goods, live animals and poultry, and as well as transportation related to the prevention or liquidation of the consequences of emergency situations. An air temperature of 28 °C is considered to be the temperature at which the road pavement structure under the influence of dynamic loadings can sharply lose its load-bearing capacity, which is one of the conditions under which a threat to traffic safety is created or roads can be damaged and destroyed. Problem statement. The analysis of the regulatory documentation showed that during designing of pavement structure, the climatic conditions of asphalt concrete performance should be taken into account and pavement must withstand the accumulation of plastic strains in summer, which requires measures to ensure its rutting resistance. At the same time, the algorithm for ensuring rut stability does not exist yet. It is quite likely that this issue can be resolved by performing appropriate research work and implementing harmonized European standards, respectively, by amending the building codes, etc. However, the question arises whether we do not perform the requirements of the regulatory documentation and design the pavement structure without considering the climatic conditions and ensuring the rut resistance of asphalt pavement, or still comply with these requirements, which should be clarified. Objective. Development of criteria for analyzing the performance conditions of asphalt concrete in the pavement structure and ensuring its rutting resistance during operation. Materials and methods. Prerequisites for the establishment of restrictions on the movement of freight vehicles at air temperatures above 28 ° C, analysis of operating conditions of asphalt concrete in the construction of pavement. Results. According to the results of the work, the influence of temperature, bitumen properties and loading time on the change of asphalt concrete properties has been established. Criteria for the analysis of climatic conditions of asphalt concrete have been developed and criteria for taking into account operating conditions have been established. Approximate bitumen grades for ensuring the asphalt concrete rutting resistance have been established on the basis of establishing the relationship between the standard properties of bitumen and operating properties. Conclusions. For evaluation of possible rut formation resistance of asphalt concrete, it is needed to perform an analysis by the bitumen grade in its composition, the total number of passes of vehicles with estimated loadings during the pavement operational term, the category of road, the type of asphalt concrete, the speed of traffic, as well as the year of pavement arrangement. In order to ensure the rut resistance of asphalt concrete, it is advisable to use the established criteria in the future during the pavement design.

Keywords

• bitumen
• temperature