Relationship between Microstructure and Macroscopic Properties of Asphalt under Different Concentrations of Snow Melting Agent

Abstract

This paper explored the relationship between microstructure characteristics and macroscopic properties of asphalt under different concentrations of snowmelt agent. Using penetration tests, ductility tests, softening point tests, dynamic shear rheological tests, infrared spectrum tests, and multistress creep recovery tests, the variation law of the microstructure characteristics and macroscopic properties of asphalt under the action of different concentrations of snowmelt agent was determined. Using grey correlation theory, the correlation between different concentrations of snowmelt agent and the macroscopic performance of asphalt was determined, and the correlation between the microstructure index and the macroscopic performance index of asphalt after different concentrations of snowmelt agent was determined. The results show that the penetration and softening point of asphalt increased under the action of different concentrations and snowmelt agent types. The ductility and the 135°C and 180°C Brinell viscosity decreased; the sulfoxide index, butadiene index, and loss modulus increased; and the phase angle decreased to varying degrees compared with the control asphalt. The relationship model of microstructure and macroscopic performance indicates that the concentration of snowmelt agent has a good correlation with the macroscopic mechanical indexes of asphalt, among which the correlation with penetration was the best, and the correlation with 180°C Brinell viscosity was poor. The S=O index and C=C index of asphalt had a good correlation with the macroscopic mechanical properties of asphalt, among which the correlation with penetration, softening point and ductility was good, and the correlation with tanδ and G*/sinδ was poor. The experimental analysis showed that different concentrations of chloride snowmelt agents and mixed snowmelt agents had a great influence on the macroperformance of asphalt, whereas nonchloride snowmelt agents had little influence on the macroperformance of asphalt. When the concentration of nonchloride snowmelt agent was 10%, the decline of macroperformance of asphalt was relatively small. The grey correlation analysis indicated that under the action of different concentrations and different types of snowmelt agents, there is a correlation between the microstructure and macroscopic performance of asphalt. When the concentration of nonchloride snowmelt agent was 10%, the macroscopic performance of asphalt decreased the least. The S=O index had the best correlation with the penetration of asphalt, and the C=C index had the best correlation with the softening point of asphalt. This paper mainly explores the correlation between the microstructure and macroscopic properties of asphalt under the action of different concentrations and different types of snow melting agents. The research in this paper further clarified the influence of different types of snow melting agents on asphalt materials. According to the research conclusions of this paper, it is recommended to use nonchlorine salt snow melting agents when spreading snow melting agents on snowy pavement.