Study On Preparation And Road Performance Of SBR Modified Slow Cracking Emulsified Asphalt

Emulsified asphalt is a kind of asphalt that can be constructed at room temperature.Emulsified asphalt products are easy to use and have good adhesion with mineral aggregate.Emulsified asphalt mixture has good fluidity at room temperature and has excellent effect on rapid repair and maintenance of roads.It can save costs,increase the service life of roads and extend the construction season.The emulsified asphalt used for micro surfacing and slurry seal is slow cracking emulsified asphalt.Most emulsified asphalt is fast cracking and medium cracking,which is not suitable for micro surfacing and slurry seal.However,the research and application of slow cracking emulsified asphalt are relatively few.Therefore,this study combines the advantages of cationic emulsifier and a new type of non-ionic emulsifier,The slow cracking asphalt emulsifier was prepared for micro surfacing construction.This paper introduces the research progress of emulsified asphalt and compound emulsifier.The advantages of surfactant compounding are analyzed,and the mechanism of emulsified asphalt is introduced.The difference between sm-100 and OP-10 was also analyzed.Through a large number of preliminary experiments,the preparation process of compound emulsified asphalt was determined.The optimum proportion of sm-100 non-ionic emulsifier and cationic emulsifier,and the optimum dosage of emulsifier and stabilizer were determined by design contrast test.When the emulsifier ratio is 7:3,the softening point and storage stability are the best.When the stabilizer content is 0.4%,the softening point and storage stability are the best.When the emulsifier content is 2.5%,the performance is the most balanced.Therefore,the best formula of emulsified asphalt is obtained: emulsifier ratio is 7:3,stabilizer content is 0.4%,emulsifier content is 2.5%.The performance comparison of self-made emulsified asphalt and OP-10 non-ionic emulsifier shows that the technical index of self-made emulsified asphalt is better.The addition of sm-100 non-ionic emulsifier not only prolongs the mixing time of emulsified asphalt,but also prolongs the demulsification time.The self-made compound emulsified asphalt belongs to slow cracking emulsified asphalt.SBR latex was used to modify the self-made emulsified asphalt.By analyzing the technical indexes of evaporation residue under different amount of SBR latex,it was found that the penetration was the lowest when the amount of SBR latex was 5%;The softening point,ductility and Enshi viscosity are the largest,so the best latex content is 5%.The results show that the peak heat flux and peak temperature range of slow cracking emulsified asphalt are higher than those of fast cracking emulsified asphalt and medium cracking emulsified asphalt.The demulsification process of emulsified asphalt with different demulsification speed and the content of evaporation residue can also be determined by DTA-TG.Dynamic shear rheometer was used to scan the temperature of self-made emulsified asphalt,compound emulsified asphalt and base asphalt.It was found that SBR latex and non-ionic emulsifier could improve the temperature stability and rutting resistance of asphalt.The road performance of micro surfacing was studied by using self-made emulsified asphalt.The gradation is MS-3,and the best mixing water content is 10%through mixing test.When the cement content is 1%-1.5%,the mixing state is the best,and the best cement content is 1% by comprehensive mixing test.The lower limit of asphalt aggregate ratio is 6.5% by wet wheel wear test,and the upper limit of asphalt aggregate ratio is 7.5% by load wheel adhesion sand test.Combined with the two test curves,the best asphalt aggregate ratio is 6.8%.The optimum mix proportion of micro surfacing mixture is determined,and the micro surfacing mixture meets the specification requirements.