This article contains the results of a study of the strength characteristics of building mortars of various compositions based on magnesia binder (magnesia oxychloride cement). The results obtained: the final compressive strength (28-day) within the studied compositions is from 12 to 45 MPa, the kinetics (rate) of strength growth on the first day of hardening is from 22 to 38%, on the third day of hardening – 33-68%, on the seventh day – from 50-88%, and about 120% from the design (28-day) with further hardening.

Keywords: magnesia oxychloride cement, magnesia binder, magnesia mortar, magnesia concrete, caustic magnesite, magnesium chloride, compressive strength, strength set kinetics