VARIATION OF TECHNOLOGICAL SCHEMES FOR THE PRODUCTION OF POZZOLANE COMPOSITIONS

Abstract

Positioning of modern building materials requires knowledge of chemical technologies, the structure of the production process to reduce the cost of the final product. Adding a part of the technogenic component to the existing and developed compositions provides quantitative advantages in terms of the material balance. Carbonate slag materials, such as cement stone and other capillary-porous bodies, may contain a certain amount of loosely bound water, which is retained by the forces of physical and chemical nature, but evaporates from the sample at temperatures up to 105°С. At such a temperature, not only capillary and adsorption moisture, which can be contained in small quantities between the powder grains, but also mainly water of loose crystal hydrates, i.e. weakly chemically bound water, evaporates from the samples. Evaporated flux, unbound in the process of hardening of the binder, forms two groups in the concrete. Pores vary dramatically in size: capillary pores and gel pores are very small in size (from 15x10-8 to 40x10-8 cm). Capillary pores located between gel particle aggregates are thousands of times larger than gel pores. They contribute to the absorption and migration of water, which freezes in them under normal cooling conditions. Therefore, capillary pores appear as the main structural defect of the pressed material. When fully hydrated, the cement gel holds about 0.25% of the water in the pores of the gel (considering the mass of cement). The technical and economic calculation of the cost of products based on carbonate slag binder, performed according to the average cost option, shows that the cost of bricks is 1.26 times lower than silicate bricks and 2.1 times lower than ordinary clay bricks for the conditions of the city of Tysmenytsia.