Research On Performance Of Waterborne Epoxy Emulsified Asphalt Based On Low Temperature Evaporation Method

Hot mixture paving asphalt pavement technology has serious energy consumption and pollution in the production and construction,the cold mixture paving technology,with traditional modified emulsified asphalt as binder,is energy saving and environmental protection,however,due to the poor adhesion of the binder,cold mix asphalt mixture has many problems such as poor water stability and durability.Waterborne epoxy modified emulsified asphalt can improve the road performance of cold mixture paving asphalt mixture,but there are significant differences in the performance of different types of waterborne epoxy emulsified asphalt,and at present,there is no definite method to evaluate the performance of waterborne epoxy emulsified asphalt.For this reason,this dissertation proposes a method to evaluate the performance of waterborne epoxy emulsified asphalt based on low temperature evaporation method,and compare and analyze the performance of waterborne epoxy emulsified asphalt based on low temperature and normal temperature evaporation method to establish its equivalent relationship,in addition,the microstructure of different waterborne epoxy emulsified asphalt is observed by microscopic means,and the relationship between the microstructure and the macroscopic performance is established.The main conclusions are as follows:Firstly,two waterborne epoxy systems(rigid and flexible),three waterborne epoxy content(10%,20%,30%),and three types of emulsified asphalt(590,A3T1,LBP1)were selected to prepare waterborne epoxy emulsified asphalt,Brookfield viscosity test was used to investigate the viscosity variation of different waterborne epoxy emulsified asphalt.The main conclusions are as follows: the results show that under the same test conditions,the viscosity of rigid waterborne epoxy emulsified asphalt is higher than that of flexible waterborne epoxy emulsified asphalt,and the construction residence time of different waterborne epoxy emulsified asphalts could meet the requirements of the specification.Secondly,the advantages and disadvantages of three different evaporation methods(direct heating evaporation method,low temperature evaporation method,and normal temperature evaporation method)are compared and analyzed,it is found that the direct heating evaporation method is not suitable for evaluating the performance of waterborne epoxy emulsified asphalt;designed the evaporation test to determine the test conditions of the low temperature and normal temperature evaporation method,the high and low temperature performance and mechanical performance of different waterborne epoxy emulsified asphalt were evaluated by DSR、MSCR、BBR and tensile tests,and the equivalent relationship between the performance evaluation of waterborne epoxy emulsified asphalt was established based on two evaporation methods.The results show that the test conditions based on the low temperature evaporation method are as follows:the test temperature is 80℃,the time is 48h(rigid waterborne epoxy emulsified asphalt)and 84h(flexible waterborne epoxy emulsified asphalt);the test temperature of the normal temperature evaporation method is 25℃,the time is respectively 10d(rigid waterborne epoxy emulsified asphalt)and 15d(flexible waterborne epoxy emulsified asphalt);based on the low temperature and normal temperature evaporation methods,the performance change law of different waterborne epoxy emulsified asphalts is highly consistent,and the equivalent conversion relationship is relatively clear;comprehensively considering the high and low temperature performance and mechanical performance of waterborne epoxy emulsified asphalt,LBP1 waterborne epoxy emulsified asphalt with rigid and flexible waterborne epoxy content of 20% and 30%,respectively,is selected.Finally,the microstructure and infrared spectra of different waterborne epoxy emulsified asphalt were observed and analyzed by laser scanning confocal microscope and infrared spectrometer.The results show that the microstructure of rigid and flexible waterborne epoxy emulsified asphalt is significantly different,with the increase of waterborne epoxy content,the waterborne epoxy particles are gradually crosslinked,the area ratio and average diameter increase significantly,and the waterborne epoxy emulsified asphalt gradually changes from asphalt continuous phase to epoxy continuous phase;because the residual C-N groups and unopened epoxy groups in rigid waterborne epoxy emulsified asphalt are less,the reaction is more sufficient and the material strength is formed earlier;rigid and flexible waterborne epoxy has the same modification mechanism for emulsified asphalt,the macro performance of waterborne epoxy emulsified asphalt depends more on the properties of waterborne epoxy cured products.