Research of the Influence of Natural Mineral Fillers on the Processes of Hydration Structure Formation in the System of Gypsum Binders

Abstract

The article provides data on the chemical and mineralogical composition of mineral resources and soda production waste as microfillers for gypsum binders. The following materials were studied as fillers of the deposit of the Republic of Karakalpakstan: bentonite clay of the Beltau deposit; marl of the Beltau deposit; glauconite of the Khujakul deposit; dune sand of the Nukus region; limestone of the Ustyurt region.

The results of diagrams and electron microscopic analyzes of the studied fillers and gypsum minerals treated at different temperatures are presented. The results obtained by measuring the plastic strength are in correlation with the data of the thermal analysis of hydration products, indicating an increase in the rate of hydration in the first minutes in the presence of all fillers increases several times. On X-ray diffraction patterns of products, the intensity of reflections characteristic of calcium sulfate dihydrate is higher in the presence of all fillers compared to products without them. This character of the dependence indicates the acceleration of the release of the dihydrate and, at the same time, the improvement of its crystallization. This confirms the positive role of the substrate in the hydrate release process.

The results of the analyzes show that the influence of the type and concentration of mineral fillers on the processes of structure formation in systems with binders obtained at different temperatures, differ in solubility and dispersion.

The chemical-mineralogical and dispersion compositions of natural raw materials and soda production wastes have been determined, which predetermine the possibility of their use as microfillers for gypsum and composite binders. The research results showed that the nature of the filler is of decisive importance in the processes of hydration structure formation and hardening of binders of all modifications. Determination of the optimal ratios of components in the system allows you to obtain binders with maximum strength values.