The main scientific and practical results of increasing environmental and economic efficiency of using the cement dust as a partial replacement for cement are presented in the article. Physical, chemical and mechanical properties of composite Portland cement were studied when replacing from 0 to 25 % of cement with cement dust for saving difficult-to-obtain binding material. Analysis was performed related to the scientific research in this area. Laboratory experiments were conducted concerning the mathematical and physical modeling of ongoing processes. The obtained results are analyzed and generalized in accordance with the standard methods proposed by the leading experts in the field of concrete science and related industries, as well as by the authors of the article.
Ecological and economic efficiency is substantiated concerning the use of the cement dust as a partial replacement of cement when producing concrete mixtures. Proposed approach is the real way to reduce the cost of concrete and decrease the environmental impact.
Efficiency of the cement dust as an additive depends on its ability to quickly interact with the composite Portland cement due to its high lime content, i.e. the higher the percentage of the cement dust, the greater the proportion of lime. With an increase in the concentration of cement dust, it is required to increase the amount of water to obtain a standard cement paste. As a result, both the initial and final cement setting time are reduced, however, the requirements of the existing standards are not violated at this time. Even when replacing cement dust with 25 % cement, the initial setting time is at least 60 minutes. Also, the addition of cement dust does not significantly affect the hydrogen potential of the concrete mixture, which is an additional argument in favor of the use of cement dust in the production of the composite Portland cement. However, an increase in the porosity of concrete products with the addition of cement dust should be considered, leading to a significant decrease in their compressive strength.