Experiments Research On Mechanical Properties Of Crts Ⅱ Type Ca Mortar Subjected To Dynamic And Static Loads

CA mortar is a key component of slab ballastless track, which performance plays an important role in railway operation. This article main research CA mortar of CRTS Ⅱ type slab ballastless track. GDS triaxial apparatus was used to conduct indoor experiment which was to study the influence of different temperature effect time and age on compressive strength performance of CA mortar. The indoor short-term dynamic triaxial test is used to study the influence of the load amplitude, confining pressure and temperature on the fatigue performance of the CA mortar. The main conclusions are as follows:(1)CA mortar was respectively placed in three temperature(25℃、40℃、60℃)10d、20d、30d, Uniaxial compression experiment was carried out at room temperature, the changing rule of peak stress, elastic modulus, stress strain curve and failure pattern of CA mortar were obtained. binary regression analysis of the peak stress related to temperature and time was obtained. The results show that along with the growth of the temperature and time, the uniaxial compressive strength of CA mortar are linear growth, the linear correlation coefficient are all above 0.9;Elastic modulus increases with the increase of temperature and placed days; Due to aging and softening migration of the asphalt in high temperature,stress strain curve of CA mortar presents brittle failure characteristics; though binary linear regression analysis,it is obtained that R2 is equal to 0.940, so there is linear correlation. High temperature for a long time in summer may increase the elastic modulus of CA mortar, leading to the CA mortar losing the effect of elastic adjustment. For the area of long-term high temperature in summer, it is suggested to improve the temperature sensitivity of CA mortar.(2) Through indoor uniaxial test it is obtained the changing rule of three kinds of mechanical parameters and the stress strain curve of CA mortar in one year. The results show that with the increase of age, the compressive strength,elastic modulus, damage modulus of CA mortar increased, ultimately to an extreme, and extreme value of the parameters were obtained by fitting formula. The relationship between Compressive strength, elastic modulus and damage modulus can be transformed through the modified unified function relation.(3) The changing rule of mechanical properties of the CA mortar under the coupling effect of confining pressure and load amplitude is obtained by indoor dynamic triaxial test. With the increase of confining pressure, the impact of load amplitude on the peak intensity weaken. Under the same load amplitude, with the increases of confining pressure, peak strength after fatigue test linear increased. The multivariate linear fitting equation of peak strength after fatigue test related to load amplitude and confining pressure was obtained. According to the fitting formula, reference for CA mortar designing under different operating conditions is provided.(4) Fatigue tests of CA mortar which was placed in different temperature for 30 days are carried out at room temperature. The results showed that the cumulative strain decreases with temperature increase; with the increase of load amplitude,the uniaxial compressive strength are linearly decreased, with the increase of temperature, the effect of load amplitude increase. Under the same load amplitude, the higher the temperature, the lower compressive strength after fatigue test, it is shows that the fatigue performance of CA mortar at high temperature for a long time becomes poor.