Study on Properties of Binary Composite Cementitious Self-leveling Mortar

The binary composite cementitious self-leveling mortar is an important development direction of modern building construction. At present, there are great differences in opinions on the mixing proportion of Portland cement and aluminate cement or sulphoaluminate cement in binary system and there are few literatures comparing the fluidity and strength of the two kinds of mortar. In this paper, the fluidity, flexural strength and compressive strength of the two kinds of mortar with different dosages were compared. The research results showed that the addition of aluminate cement and sulphoaluminate cement could reduce the initial fluidity and 20min fluidity of mortars, but the decreasing degree was different. The influence of different dosages of aluminate cement and sulphoaluminate cement on the flexural strength and compressive strength of mortars was obviously different. When the dosage of aluminate cement was 0-10%, the flexural strength and 1d compressive strength of mortar could be improved remarkably. When the dosage was higher than 10%, the strengths were obviously reduced, even lower than the strengths of Portland cement mortar. The flexural strength of the mortar increased with the increase of sulphoaluminate cement in the range of test dosages, but the 1d compressive strength had little difference. When the dosage was 10%-20%, the influences of the two kinds of cement on the 28d compressive strength of mortars were basically consistent and both could improve the 28d compressive strength of mortars. (paper)