Effect Of Cold Recycling Agent On Road Performance Of Emulsified Asphalt Cold Recycling Mixture

In the preparation process of the traditional emulsified asphalt cold recycling mixture,the aging asphalt wrapped on the surface of the asphalt pavement recycling material(RAP)is usually ignored,and the rap material is directly used as"black stone".The water stability,cracking resistance and spalling resistance of the cold recycled mixture prepared by this method are often poor.In view of this,this study introduces a special cold recycling agent for asphalt pavement recycling materials,through the recycling effect of cold recycling agent,it is expected to improve the traditional cold recycling mixture in water stability,anti cracking performance and anti peeling performance.Evaluation of the regeneration effects of several existing cold regenerators,and finally determined that 6~#cold regenerator is the best type of regenerator;the attribute analysis of the existing RAP material found that the material has a low asphalt content Therefore,the laboratory was selected to simulate the preparation of aging asphalt mixture to carry out subsequent cold regeneration research;the gradation of cold regeneration mixture and the optimal dosage of regenerant,water and emulsified asphalt were determined.Using time and temperature as the influencing factors of the regeneration effect,the mechanical properties and volume of the cold recycled mixture at different regeneration temperatures(40?,50?)and time(2 days,5 days,7 days,10 days)were analyzed index.The results of the study indicate that the extension of the regeneration time will increase the porosity of the regenerated mixture and reduce the cleavage strength of the mixture,and the higher the temperature,the greater the impact;Increase;the addition of cold regenerator makes the anti-deformation ability of the regenerated mixture decrease.From the four aspects of water stability,high temperature stability,spall resistance and low temperature crack resistance,the influence of cold regenerant on the road performance of regenerated mixture was analyzed.The results show that:the addition of cold regenerant improves the ability of the regenerated mixture to resist freeze-thaw damage;the high temperature stability of the regenerated mixture meets the requirements of the cold regeneration specification;the anti-stripping performance of the regenerated mixture is also obtained due to the use of the cold regenerator Improvement,and the longer the regeneration time,the better the anti-stripping performance;when the regeneration temperature is 40?,the addition of cold regeneration agent improves the low temperature cracking resistance of the regeneration mixture,but when the regeneration temperature rises to 50?,the regeneration Instead,the low temperature cracking resistance of the mixture is reducedWith the help of SEM and contact angle instrument,the interfacial adhesion,internal structure and wettability improvement of recycled mixture were studied,so as to analyze the mechanism of cold recycled agent improving the road performance of recycled mixture.The results show that the addition of cold regenerant can improve the adhesive property of the interface between the glue and aggregate,improve the internal structure of the glue,and make the microstructure of the glue more compact.On the other hand,the regeneration of cold regenerant can improve the wettability of rap material surface,which will be helpful to the wrapping property of the glue.In summary,this study prepared the improved emulsified asphalt cold recycling mixture by using the special cold recycling agent for asphalt pavement recycling materials.Its water stability,anti cracking performance and anti peeling performance are effectively improved compared with the traditional cold recycling mixture,and it is expected to be widely used in the pavement structure of the road.