Abstract: Cement and asphalt mortar (CA mortar) is the filling layer material of the slab track of high-speed railway. Uniaxial compression test was carried out on CA mortar specimens of different ages by CSS8810 electronic universal testing machine. Results show that the mechanical properties of CA mortar display obvious age effect, and the peak stress and elastic modulus gradually increase with the growth of age. The stress-strain relation of CA mortar displays obvious strain hardening characteristic, and the lateral constraint of asphalt network structure is the main influencing factor. Through theoretical derivation, the damage constitutive relation of CA mortar was established in consideration of the carrying capacity of the damaged part through mutual friction. The fitting result is highly consistent with test curves, and effectively reflects the age effect and strain hardening characteristics of the mechanical properties of CA mortar. The research result is expected to promote the research on mechanical properties of CA mortar.

Key words: CA mortar, age effect, stress-strain, strain hardening, constitutive relation