Study On Waterborne Epoxy Emulsified Asphalt Cold Mixture And Its Pavement Performance

Emulsified asphalt mixture has many problems such as low initial strength,long molding time and poor high temperature stability.Based on the high strength,weatherability and super adhesion ability of waterborne epoxy resin,waterborne epoxy resin is used as modifier to prepare waterborne epoxy resin modified emulsified bitumen,which improves the poor adhesion of emulsified bitumen and poor stability at high temperature.A new cold-repairing mixture suitable for rapid repair of asphalt pavement is developed.In this paper,E51 epoxy resin and polyethylene glycol 4000(PEG4000)were used as raw materials to synthesize non ionic emulsifiers by chemical grafting.Waterborne epoxy resin was prepared by phase inversion,and the best emulsifier content was determined through the characterization of emulsion particle size,storage stability and centrifugal stability.Fourier infrared spectroscopy(FT-IR),scanning electron microscopy(SEM)and thermogravimetric analyzer(TG)were used to characterize the curing reaction time,structure and thermal stability of the waterborne epoxy resin.The curing time of waterborne epoxy resin was determined,and The results showed that the structure of the aqueous epoxy resin solid was compact and the high temperature stability was good.Water-borne epoxy emulsified asphalt binder was prepared by a cold mixing method.The optimum preparation process was determined by drawing test.The storage stability test and boiling test showed that the compatibility of waterborne epoxy emulsified asphalt and the adhesion of the aggregate were good.The dynamic shear rheometer(DSR)was used to characterize the high temperature rheological properties of the cemented material,and its linear viscoelastic range was determined.The waterborne epoxy resin could significantly improve the high temperature stability of the emulsified bitumen.The thermal analyzer(DSC),SEM and fluorescence microscope were used to characterize the glass state temperature(Tg)and microstructure of the cemented material.The results showed that with the increase of the amount of waterborne epoxy resin,the Tg of the binder was gradually increased,and the epoxy resin was formed as the framework and the asphalt was interspersed in the framework.The water-borne epoxy emulsified asphalt is used as binder,AC-13 gradation is selected to design the cold-repairing mixture.According to Marshall test and the indexof water loss rate,the optimum cement content,total water consumption,health technology and retention time of the water-borne epoxy emulsified asphalt cold fill are determined.The analysis of the pavement performance of the cold-repairing mixture shows that with the increase of the amount of waterborne epoxy resin,the flexural tensile strength and the bending strain of the cold-repairing mixture get the maximum value when the water epoxy resin content is 20%,and the high temperature performance and the water stability are greatly improved.Under the Optimal mix ratio,cement was used as modifier to prepare early strength cold-repairing mixture,and the forming process was determined by Marshall test.The cement can accelerate emulsified bitumen demulsification,the internal moisture volatilization of the cold-repairing mixture and reduce the retention time.Under the condition of room temperature curing,the early strong cold-repairing mixture still has good water stability.The test of pit groove repair shows that the intensity of early strength cold-repairing material is faster,and it can meet the requirements of rapid repair of asphalt pavement.