Creep properties of cement and asphalt mortar

•The creep process of type I, II CA mortar was analyzed.•The relationship between the creep volume and load level was expressed by equation.•The microscopic response mechanism of creep properties of CA mortar was analyzed.•The long-term strength of CA mortar was determined to be 0.4σp.•The established creep model can effectively predict the creep deformation of CA mortar.

In order to study the long-term deformation properties of cement and asphalt mortar (CA mortar), the creep properties of CA mortar on different load levels were studied by independently designed creep testing apparatus. The experimental results show that the creep deformation of CA mortar can be divided into the attenuation creep stage in which the deformation rate decreases gradually and the steady creep stage in which the creep rate is relatively stable. The greater the load is, the bigger the deformation rate and the creep deformation in every stage are. The specific creep of type I CA mortar is bigger than that of type II CA mortar. The long-term strength of two kinds of CA mortar is 0.4σp which is calculated by the method of isochronous stress–strain curves. A creep model of CA mortar based on the thermodynamic theory is established, and the correlation coefficients between fitting results of model and experimental results are all greater than 0.98. The study results can improve the structural design theory of ballastless slab track.