Blast furnace slag is a waste of metallurgical industry which can be used in production technology of concretes and mortars. The expedient use of blast furnace slag as a component for new building materials will improve the environmental situation and increase the economic efficiency of production. The authors reaserch blast furnace slag processing technology of factories "Hoa Phat" (Vietnam) and "Thai Nguyen" (Vietnam) to produce mineral additives. As a result of the conducted researches the chemical and mineralogical composition of slags are received, their physical and mechanical characteristics are considered and defined: specific surface area, density, water demand, and others. 
 According to standard of Vietnam and Russia, slag activity index is calculated when considering the possibility of using blast furnace slags to replace part of the binder. The relationship between the strength of the cement-sand mortar and density affected by the binder are reveald (where; binder = Portland cement + Granulated blast furnace slag). Comparison chart of slag activity index IR (%) has been shown.
 The paper uses the Vietnamese standard TCVN 11586: 2016 to analyze the possibility of using blast furnace slag (Vietnam) in the technology of concrete and mortar construction.