EVALUATION OF THE EFFECTIVENESS OF INFLUENCE CAUSED BY ULTRA AND NANO-DISPERSE ADDITIVES FOR MODIFICATION OF SULFATE PHASES AND SULFOALUMINATE PHASES

Abstract

Problem statement. We offer stabilization of ettringite with the help of nanocomponents introduced. When conducting these studies, the problem of developing compositions of new construction materials based on gypsum and cement binder was solved by means of introducing nano-additives. Nanotechnology is a tool that allows you to reliably understand the processes that occur during hydration of composite materials, interaction of chemical and mineral additives with newly formed hydrated structures, formation and development of macro- and microstructure. The next stage in the effective application of nanotechnologies and techniques used in nanotechnologies for studying hydration processes and structure formation of gypsum- and cement-containing binding materials consists in the development of molecular models of hydration of Portland cement products. Creation of a high-strength cement frame is possible by adjusting the size of the solid phase and crystallization centers, as well as by modifying the gypsum- and cement-containing binder with ultra and nanodisperse additives. Purpose is to investigate effectiveness of ultra- and nanodisperse additives for modification of sulfate phases and sulfoaluminate phases. Conclusions. Modification of the compositions of radiation protection solutions of sulfate phases and sulfoaluminate phases with nanodisperse additives led to a decrease in the coefficient of linear expansion to 0.8 %. Herewith, an increase in solid indicators occurred by 8−12 %, which was caused by a change in the structure of neoplasms and the mineralogical composition. Thus, modification of the solution of sulfate and sulfoaluminate phases with carbon nanotubes (CNTs) leads to a decrease in the coefficient of linear expansion and an increase in the scattering coefficient of gamma rays by 30−40 % due to a high specific surface area of CNTs (80−120 m2/g). An optimal solution with the following composition has been experimentally developed: alumina cement, gypsum, BaSO4, nanotubes. It has been established that this solution has a 10−15 % higher water content, which is associated with the formation of ettringite during the process of setting and hardening. As a result, the arithmetic average amount of chemically bound moisture increased, which affected the change in the linear attenuation coefficient of ionizing radiation of the coating by 0.0088−0.009 cm-1. The total coefficient can reach 0,354 cm-1. Such results lead to reduced equivalent thickness (14,6 mm) of the radiation protective layer by 1−1,5 mm.