THE INFLUENCE OF THE STRUCTURAL CHARACTERISTICS OF MAGNESIA BINDERS ON THEIR WATER AND SALT RESISTANCE

The influence of amorphous silica, plasticizer, water-repelling agent and integrated hydrophobic plasticizing additives on structural characteristics, physico-mechanical, hydrophysical characteristics and salt resistance of magnesia binders was studied. Some of the structural parameters (average and true density; density coefficient; total, open and closed porosity) were matched to compressive strength, water and salt absorption, water and salt resistance of the materials. It is shown that the introduction of the amorphous silica contributes to the forming of water resistant magnesium-siliceous structures, clogging of the pore space of silicic acid and small increase of closed porosity, and the use of a plasticizer, water-repelling agent and integrated hydrophobic plasticizers - to increase of the density of magnesia structures, a substantial increase in closed porosity as the result of the forming of the solid mosaic hydrophobic films on the surface, which has a positive effect on many of the technological characteristics of magnesia materials. 

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