Дороги і мости (Apr 2022)
SELECTION OF BITUMEN FOR THE PRODUCTION OF ASPHALT CONCRETE MIXTURES CONSIDERING THE OPERATING CONDITIONS
Abstract
Introduction. Asphalt concrete is the most common material for paving layers of roads. Significant advantages of asphalt concrete include high operational characteristics, relatively high technical values, suitability for regeneration and more. At the same time, asphalt concrete has its drawbacks, one of which is the significant dependence of strength and deformation characteristics fronm the ambient temperature. The essential role in the temperature properties of asphalt concrete is played by bitumen, the quality of which is currently evaluated by standard indicators in accordance with the penetration system. The properties of bitumen can be more accurately and objectively evaluated by rheological indicators (viscosity and cohesion) or by operational ones, which are determined depending on the climatic conditions of asphalt concrete layers. Therefore, there is a need to analyze the climatic conditions of asphalt concrete in the pavement structure. Problem statement. Today in Ukraine a penetration system uses for evaluation of bitumen properties that determines the type of bitumen and the corresponding characteristics. About 30 years ago, the United States developed a system for evaluation of bitumen operational characteristics, which combines climatic conditions and transport loadings. This approach allows to choose bitumen for assigned designing combination of high and low temperatures. Evaluation of the appropriate climatic conditions of asphalt concrete in Ukraine will allow to develop zoning on the basis of which it is possible to make the optimal choice of bitumen, which would increase the durability of asphalt concrete and pavement structure in general. Purpose. Creation of bitumen selection system during designing of pavement structure, considering the ambient temperature, transport loadings, traffic intensity, level of reliability and location of asphalt concrete in the pavement structure. Materials and methods. Collection of climatic data regarding ambient temperature according to the data of meteorological stations located in regional centers of Ukraine for the period from 2005 till 2020 and determination of the needed operational properties of bitumen. Results. The zoning of the territory of Ukraine according to the climatic conditions of asphalt concrete considering the ambient temperature, transport loadings, traffic intensity, level of reliability and location of asphalt concrete in the pavement structure is developed. Conclusions. Development and introduction of zoning of the territory of Ukraine according to the operational conditions of asphalt concrete and bitumen selection system according to operational indicators will prevent the formation of destruction in the form of plastic deformations, cracks and low-temperature cracks and thus will increase the durability of asphalt concrete.
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