Study On The Effect Of Chemical Composition Characteristics Of Aggregate On Mass Transfer And Demulsification Speed Of Emulsified Asphalt

At present,most domestic high-grade highways need to be maintained.Faced with increasingly heavy road maintenance and maintenance tasks,in-situ thermal regeneration and warm mix thermal regeneration technology of asphalt mixture have been widely used in road maintenance.Compared with the first two road maintenance technologies,the use of emulsified asphalt mixture for road maintenance has higher energy-saving and environmental protection effects.However,the instability of the performance of emulsified asphalt mixture affects the popularization of this technology.In emulsified asphalt mixture,emulsified asphalt is one of the main components of the mixture,and its performance directly affects the use of emulsified asphalt mixture.At present,it is found that the shortage of emulsified asphalt performance is mainly related to the demulsification speed of emulsified asphalt.At present,the demulsification speed of emulsified asphalt mixture is mainly studied from the nature of emulsified asphalt itself,and the relationship between the characteristics of aggregate and the chemical composition of aggregate and the demulsification speed of emulsified asphalt is less studied.At present,the subjective experience method is still used to judge the demulsification speed of emulsified asphalt.The relationship between aggregate characteristics,chemical composition characteristics of aggregate and demulsification speed of emulsified asphalt is not clear,and the demulsification speed of emulsified asphalt can not be accurately predicted.In this paper,mass transfer and adsorption test of emulsified asphalt and demulsification speed test of emulsified asphalt mortar are used to study the influence of chemical composition characteristics of aggregate on mass transfer and demulsification speed of emulsified asphalt.(1)In this paper,the storage stability of STAC/SDBS emulsified asphalt is used as an index to evaluate the performance of emulsified asphalt.By investigating the preparation technology of STAC/SDBS emulsified asphalt,the suitable preparation technology of emulsified asphalt was selected,and the performance of the emulsified asphalt prepared for mass transfer and demulsification speed test was tested.(2)Because there are many uncontrollable factors in coarse and fine aggregates,five main chemical components of aggregates and calcium carbonate are used to replace coarse and fine aggregates as research objects.Surface energy parameters,specific surface area,pH value and alkali value were used to characterize the chemical composition characteristics of aggregates,and grey correlation theory was used to analyze the correlation between these characteristics.(3)Mass transfer and adsorption capacity of mass transfer system is characterized by conductivity ratio of aggregate chemical composition to emulsified asphalt mass transfer system,and demulsification speed of emulsified asphalt mortar is evaluated scientifically and objectively according to demulsification model of emulsified asphalt mortar.(4)The influence of aggregate chemical composition,emulsifier content and solid content on mass transfer process of STAC/SDBS emulsified asphalt was analyzed by orthogonal test of aggregate chemical composition/emulsified asphalt mass transfer system.The results show that the chemical composition of aggregate is a significant factor affecting the conductivity ratio.Grey relational analysis was used to study the grey relational relationship between chemical composition characteristics and conductivity ratio of aggregates.The results show that in the mass transfer system of cationic(STAC)emulsified asphalt,the grey comprehensive correlation degree between pH value and conductivity ratio is the highest,and the grey correlation degree of specific surface area,surface energy,alkali value and conductivity ratio is also larger.In anionic(SDBS)emulsified asphalt mass transfer system,the grey comprehensive correlation degree of alkali value and conductivity ratio is the highest,and the grey comprehensive correlation degree of surface energy,pH value and conductivity ratio is also larger,while the grey comprehensive correlation degree of specific surface area and conductivity ratio is smaller.(5)Through grey correlation analysis of chemical composition characteristics of aggregate and demulsification speed of emulsified asphalt mortar,it was found that pH value and mixing ratio of asphalt mortar were the key factors affecting demulsification speed of STAC/SDBS emulsified asphalt mortar;surface energy and alkali value also had great influence on demulsification speed of STAC/SDBS emulsified asphalt mortar;specific surface area had little influence on demulsification speed of STAC/SDBS emulsified asphalt mortar.