Study On Using Performance Of Crts-Ⅱ Type Cement Asphalt Mortar And Its Influencing Factors

CRTS-Ⅱ-type slab ballastless track is one of non-ballasted track structure which is widely used in the current high-speed railway for its benefits of stability and ride comfort. Cement asphalt mortar(hereinafter abbreviated to CA mortar) is a key material of CRTS-Ⅱ-type non-ballasted track construction , which application technology has become a hot issues in the railway construction. In order to reveal the interaction and change rule of the composition, structure and properties of CA mortar, physical and mechanical properties, construction performance and service performance of CA mortar is studied to begin with selection of raw materials.Through this research, it can provide an important reference to promote the development and application of CA mortar.The originality innovation of this thesis is summarized as following:First of all, by analysizing rheological properties and effect of particle deposition of CA mortar mixture, emulsified asphalt and sand gradation range which is more suitable for use in CA mortar is optimized.Secondly, the variation of physical and mechanical properties of CA mortar was studied in detail by change of the mass ratio of asphalt to cement, the mass ratio of sand to cement. Through it, the main effects on physical and mechanical properties of CA mortar are proposed. Simultaneously,combined with the mechanical properties of the problem, Using SEM, EDX and other modern testing methods the relationship between the microstructure characteristics and physical and mechanical properties of CA mortar was studied. With the results, the mechanism of physical and mechanical properties of CA mortar is proposed.They show that strength of cement asphalt composite mastics and interfacial bond conditions between mortar and sand is the main reasons effects the physical and mechanical properties of CA mortar.Thirdly,a mixing process of CA mortar was optimized through some mixing experiments,and on this basis,the effect laws of the construction performance of CA mortar was studied.Results show that Materials'temperature and coagulation regulator are the reasons of the early strength of CA mortar. The Ratio of Water to Cement, defoamer and superplasticizer dosage are three major factors affect workability of CA mortar. The Ratio of Water to Cement, defoamer and superplasticizer dosage have some impact on liquidity. Defoamer content impact CA mortar's gas content. Superplasticizer dosage impact the working hours of CA mortar. CA mortar's liquidity and gas content can impact the separation and bleeding phenomenon of CA mortar,and CA mortar's liquidity and gas content also interacte each other.With these test analysis, the preparation technology of CA mortar's workability was proposed. CA mortar expansion rate determined by the amount of aluminum powder.At last, damping capacity, high temperature performance and frost resistance of CA mortar was studied and this work maked up the disadvantage of the service performance's research of CA mortar in the current. The stability of damping capacity of CA mortar was studied at different temperatures and different test frequencies. With low shrinkage characteristics of CA mortar'research, measures are proposed to improve the low shrinkage performance of CA mortar. By high temperature creep and one-side freeze-thaw test ,results indicate that the CA mortar has a high capacity high-temperature stability and freeze-thaw resistance.