Abstract:The existing self-leveling mortar is mostly prepared from sulphoaluminate cement and solid admixtures, which results in high cost, short shelf life and unstable performance. In this paper, ternary composite cementitious materials of Portland cement-ultrafine Portland cement-mineral powder and liquid admixtures were used to prepare Portland cement based two-component self-leveling mortar. The influence of the composition and the matching of the cementitious materials and admixtures on the flowability, mechanical properties, and shrinkage of the self-leveling mortar was investigated. The results indicated that the two-component self-leveling Portland cement-based mortar can meet the desired performance standards of initial and 20 min fluidity of over 140 mm, 1 d compressive and flexural strengths were 6.2 MPa and 5.2 MPa, respectively, the 7 d tensile adhesive strength was 1.45 MPa, and the 7 d shrinkage value was only 0.1%,when the water-cement ratio was 0.55, and 5% ultrafine Portland cement, 4% Type Ⅱ gypsum, 0.5‰ shrinkage reducing agent (SRA), and 12% high-performance expansive agent (HCSA)was added.