The Use of Mineral Ultra-Disperse Modifiers on the Basis of Industrial Wastes in Gypsum Composites

The use of modern building composites requires ensuring their high performance – density, durability, water resistance, etc. One of the ways to improve the properties of composite binders based on gypsum is introduction of additives. The existing classifications of additives evaluate their role differently. The most interesting classifications subdivide additives according to the mechanism of their impact on the gypsum stone or participation in phase formation. The paper summarizes the results of studies of modification of composites based on the dihydrate of calcium sulfate with mineral ultra-disperse additives. By-products of production such as micro-calcite, micro-silica and industrial wastes as dust of basalt production are used as such additives. The choice of additives is due to their dispersion and chemical composition. Comparative analysis of additives shows that they are all applicable to nonburning gypsum binders, but the mechanisms of their action are different. Research in the influence of silica fume additive has been established the increase in the strength of the composite, due to its impact on the value of the solubility of the initial phase. The addition of micro-calcite can be characterized as a structure-forming. The affinity of the additive and binder structures when re-crystallizing non-hydration hardening systems contributes to the most favorable conditions. In the case of using the dust-like waste of basalt production as a dispersed additive for gypsum systems of non–hydration hardening, a special role is played by the pH of the pore liquid, which limits the process of structure formation, as well as the size and morphology of the crystals of the new phase of the modified gypsum stone. At increased values of the hydrogen index, characteristic for gypsum compositions with basalt component, the processes of structure formation will proceed more actively.

V.В. PETROPAVLOVSKAYA, Candidate of Science (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.)

Tver State Technical University (22, Afanasiy Nikitin Еmbankment, Tver, 170026, Russian Federation)

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