Study On Affecting Factors And Mechanism Of Cement Asphalt Mortar’s Separation Degree

Cement and emulsified asphalt mortar (CA mortar),which is a kind of organic and inorganic compound material consists of the cement, sand and emulsified asphalt, is one of the key materials of the slab ballastless track structure and a kind of non-uniform material. Because of the difference of cement, sand, emulsified asphalt density, it exists phenomenon of the floating of emulsified asphalt and the settling of sand, which leads to the difference of work performance and durability between the upper and lower part. Based on the separation degree, the paper analysis the major factors influencing the separation degree and explore the method of reducing separating degree. With China’s high iron rapid development and the needs of the urban traffic, the content of the project research not only has the meaning of science and technology, and is more important social and economic significance.This paper studied the influence of admixtures on the zeta potential of emulsified asphalt, separating degree of cement-asphalt slurry and cement-asphalt-aggregate slurry, asphalt-aggregate adhesion. This paper explored the way of reducing separating degree of slurry. The influence of pH of emulsified asphalt on CA mortar work performance was studied in this paper based on effect of pH on zeta potential. What’s more, the paper compared the difference work performance of the cement slurry, cement-asphalt slurry, cement mortar and Cement and emulsified asphalt mortar.The main conclusions are summarized as follows:(1) The addition of stabilizer is better than the addition of emulsifier to improve the Zeta potential and reduce separating degree of slurry. The organic stabilizer is superior to the inorganic stabilizer. The effect of mixing emulsifier and stabilizer is better than single-doped emulsifier and stabilizer.(2) The pH of emulsified asphalt had great impact on the fluidity, working time, separating degree, air content and apparent density and pH of CA mortar, which laid in the influence of pH of emulsified asphalt on zeta potential. The bigger the absolute value,the smaller the separating degree. The smaller the absolute value, the bigger the separating.(3) The addition of emulsified asphalt in slurry has a role in promoting the settlement of sand in the paste system, improving separating degree of the slurry. Emulsified asphalt slurry increases the fluidity and the work time. The four sclerosis slurry are negatively charged, emulsified asphalt reduces the potential of paste.(4) The appropriate pH of asphalt for CA mortar was1.5or9.5.