Study On Performance And Application Technology Of Emulsified Asphalt Used In The Central Plant Cold Recycling

Emulsified asphalt can be used to regenerate the old asphalt pavement at normal temperature,which has the characteristics of saving resources and reducing environmental pollution.It is the key material to generalize the cold recycling technology successfully.In this paper,the principle of emulsified asphalt,the action mechanism of emulsified asphalt and aggregate,and the mechanism of the formation of emulsified asphalt cold recycled mixture were analyzed.The three kinds of cationic slow-crack emulsifier and a cationic cracker emulsifier were used to prepare emulsified asphalt and the technical indexes of emulsified asphalt were studied.It is concluded that the slow-crack and medium-setting emulsified asphalt is suitable for central plant cold recycling technology according to the characteristics;The properties of RAP were studied systematically,and the aggregate condition and aging degree of old asphalt were evaluated.Combined with the common design method at home and abroad,the gradation of cold recycled mixture was determined;The optimum water content of the recycled mixture was determined based on the vibration compaction test.The optimum amount of emulsified asphalt in the recycled mixture was determined based on the principle that the maximum splitting strength and the wet splitting strength and the dry and wet splitting strength ratio are bigger.The bulk density and percent air voids of mixtures were measured by the way of wax sealing method,and the mechanical properties of four kinds of emulsified asphalt cold recycled mixture were studied by means of Marshall compaction method.The splitting strength,high temperature stability and 7d unconfined compressive strength of the mixture were studied based on the splitting test,the rutting test and unconfined compression strength test respectively.According to the freeze-thaw splitting test and Marshall stability test,the resistance to water damage of the mixture was studied.The effect of cement content on the pavement performance of cold recycled mixture was studied under the condition of the optimum water content and the optimum asphalt content.By comparing the performance index of three kinds of cationic slow-crack emulsified asphalt cold recycled mixture and a cationic medium-crack emulsified asphalt cold recycled mixture,the results show that the cationic slow-crack and medium-setting emulsified asphalt has the best performance,so as to determine its applicability in central plant cold recycling technology.According to the law of the performance of recycled mixture under different cement content,taking into account the strength,water stability,unconfined compressive strength and lower engineering cost,the amount of cement was determined.Finally,through the analysis of the economic and social benefits of emulsified asphalt cold recycling technology,fully demonstrates the considerable economic value and significant environmental protection value of emulsified asphalt used in cold recycling technologyThe results of this study can be used as reference for the selection of emulsified asphalt used in central plant cold recycling engineering and provide an experimental basis for further study on emulsified asphalt which is suitable for cold recycling plant.