Research And Development Of Ultra High Viscosity Emulsified Asphalt And Its Performance

Ultra thin wearing layer,as a common form of pavement maintenance in today’s asphalt pavement maintenance technology,can efficiently and quickly repair mild rutting,pavement cracking,whitening and loosening,and has the advantages of improving skid resistance,reducing noise,and reducing water mist.Nowadays,the asphalt used in ultra-thin wearing layer technology is usually hot mix asphalt.In response to China’s strong advocacy for economic and environmental benefits,ultra-thin wearing layer technology has a trend of gradually transitioning from hot mix mixtures to warm mix and cold mix mixtures.While ensuring the durability of the ultra-thin wearing layer cover,it further enhances its environmental effects.Therefore,this article focuses on ultra-high viscosity emulsified asphalt as the research focus to meet the performance requirements of emulsified asphalt used in ultra-thin wear layers.By comparing the preparation process routes of three types of emulsified asphalt,it is shown that the most feasible method for preparing the required ultra-high viscosity emulsified asphalt is to modify it first and then emulsify it.On this basis,two process routes were adopted to prepare modified asphalt to obtain high viscosity modified asphalt suitable for producing ultra-high viscosity emulsified asphalt.One is to prepare high viscosity modified asphalt by increasing the dosage of SBS modifier,and the other is to directly add the high viscosity modifier to I-D SBS modified asphalt to prepare high viscosity modified asphalt.The experimental results show that preparing modified asphalt by increasing the amount of SBS modifier is difficult to meet the requirements of 60 ℃ dynamic viscosity for high viscosity modified asphalt in ultra-high viscosity emulsified asphalt;When a high viscosity modifier is directly added to I-D SBS modified asphalt,the 60 ℃ dynamic viscosity of the prepared high viscosity modified asphalt is in the ideal range.Therefore,the preparation method of adding a high viscosity modifier directly to I-D SBS modified asphalt will be adopted.Six types of emulsifiers with strong emulsifying ability were initially screened,among which imidazoline cationic emulsifiers were used as the base emulsifier and compounded with the other five types of emulsifiers.The ultra-high viscosity emulsified asphalt was investigated from the aspects of emulsion breaking speed,storage stability,standard viscosity,and evaporation residue performance indicators,and the optimal emulsifier combination type and dosage were selected.Secondly,in order to further improve the storage stability of ultra-high viscosity emulsified asphalt,a combination of organic and inorganic stabilizers is used to solve the problem of poor storage stability of emulsified asphalt.Furthermore,in order to optimize the preparation process of ultra-high viscosity emulsified asphalt,the effects of soap p H value and temperature,oil-water ratio,asphalt emulsification temperature,and emulsification shear time on the comprehensive performance of ultra-high viscosity emulsified asphalt were investigated,and the optimal preparation process of ultra-high viscosity emulsified asphalt was ultimately determined,the final prepared ultra-high viscosity emulsified asphalt has a dynamic viscosity of 113368pa· s at60 ℃.Adopting a single particle size mixture ratio,the construction performance and mixture performance of ultra-high viscosity emulsified asphalt were verified through mixing tests,cohesion tests,and 1-hour and 6-day wet wheel wear tests.The tests showed that the construction performance and road mixture performance of the ultra-high viscosity emulsified asphalt prepared by the above method were good,and it can meet the requirements of modern ultra-thin wear layers for asphalt performance.