No abstract

Analyzing fungus resistance of gypsum and organic composites is extremely important since fungi may both lead to deterioration in mechanical and operational properties of construction materials and adversely affect people’s health, including development of chronic diseases. We study fungus resistance and fungicidity characteristics of popular finishing gypsum and organic (epoxy- and polyester-based) composites. Plaster materials get exposed to micromycete biocorrosion faster than the ones based on a polymeric binding. Micromycetes adapt on plaster samples quicker than on epoxy and polyester samples. During their metabolism, micromycetes intensively allocate acid products on plaster samples, their high enzymatic activity is also noticed on polymeric materials.

Water-soluble polymer and latex additives are used to give the gypsum building plaster elasticity and placeability, improved water resistance and increased bending strength. The nanomodifiers in the form of carbon single-layer and multi-layer nanotubes, fullerenes and other nanoparticles are used for the formation of the structure of a gypsum stone with improved strength characteristics and improved weather resistance. In this work, the joint effect of the plasticizer based on polycarboxylate and the carbon nanomodifier on the structure, physicomechanical properties, and water resistance of the gypsum stone is investigated. It is shown that nanomodifiers contribute to the increase in the plasticizing ability of carboxylate additives, which leads to the significant decrease in the amount of mixing water, and as a result, to the increase in density, decrease in the porosity of the gypsum stone and the increase in its strength characteristics and water resistance.

The properties of various thermal modifications and forms of calcium sulfate and the conditions of their mutual transition are studied. It is established that the mode of heat treatment of gypsum raw materials affects significantly the nature of the subsequent hydration of the gypsum binder. It is established that the values of pH and pCa suspensions of gypsum binders depend on the temperature of heat treatment of natural gypsum, vary over time and characterize the processes occurring during hydration and hardening of gypsum binders. The values of pH and pCa suspensions of gypsum binders can serve as design criteria for innovative multiphase gypsum binders.