Research On Hardening Process And Hardening Mechanism Of Cement Asphalt Composite Binder

Cement asphalt composite binder(CA composite binder)is an inorganic-organic composite material.It is made of cement,asphalt,and various additives that are hardened and cemented.CA composite binder is the cement material for the CA mortar of the high-speed railway ballastless track cushion.It can also be used for road semi-flexible base and road surface repair materials.CA Composite Binder Hardening Molding Stage,the interaction of cement and emulsified asphalt makes the cement material microstructure,macroscopic properties,etc.continue to change,a direct impact on cement binder construction performance and service performance.This paper focuses on the hardening process of CA composite binders,focusing on the rheological properties,electrical properties,microstructure changes and the interaction mechanism of cement and emulsified asphalt in the hardening process.Based on the principle of compatibility of raw materials,the evaluation index of raw material performance was determined,and the varieties of cement,emulsified asphalt,and admixtures were determined.Based on the design of CA mortar mix ratio in the construction of high-speed rail and road projects,CA composite binder mixing technology and raw material ratio were determined.The research methods for the rheological properties,electrical properties and microstructure of CA composite binder during hardening were determined.Based on the basic theory of non-Newtonian fluids,the change of fluid type of CA composite binder during hardening was analyzed.The rheological curves of CA composite binder in the hardening process were measured,and the influence of C/A and admixtures on the rheological type of binder was analyzed.Based on the basic theory of thixotropic fluids,the characterization method of thixotropy of CA composite binder was determined,the change of thixotropy of cementing material during hardening process was studied,and the influence of C/A and admixtures on thixotropic properties of cementing material was analyzed.The variation of theviscosity of CA composite binder in the hardening process was studied,and the influence of C/A and shear rate on the viscosity of the binder was analyzed.Based on the basic theory of Fluid rheology model,the rheological application model for the hardening process of CA composite binder was determined,and the time-dependent properties of the yield stress,rheological index,consistency coefficient and other parameters in the hardening process of the Herschel-Bulkley model were analyzed.Analysis of fluidity over time,the relationship between fluidity and yield stress was established.Combined with the sensitivity analysis of rheological parameters in the hardening process of CA composite binder,the characterization index of rheological property change in the hardening process of binder was determined,and a prediction model of yield stress was established.Based on the mechanism of cement hydration and emulsified asphalt demulsification,the degree of hydration of cement and the demulsification degree of emulsified asphalt during the hardening process of CA composite binder were determined.The influence of emulsified asphalt on the hydration heat of cement,Initial/final setting time and the influence of cement on Zeta potential of emulsified asphalt were studied.Based on the resistivity method and microstructure analysis,the interaction between CA composite binder and emulsified asphalt was studied.Based on the interaction mechanism of cement hydration and emulsion emulsion demulsification,the hardening process of CA composite binder was analyzed.