Technology of Polymer-cement Mixes Preparation with Specified Rheological Properties Technology of Polymer-cement Mixes Preparation with Specified Rheological Properties

In recent years, many new materials appeared on our construction market: polymer pastes, sealants, primers, foam. In addition, dry mixes have been suffered some changes. Previously, for the bonding of stones, leveling and processing of walls and ceilings lime, clay, alabaster, gypsum, and mixtures were used. Before the use, they are diluted with water. The development of dry mixes conducted in order to increase joint strength of materials and ease of their application. Previously construction mixtures were made directly on the construction site, under such conditions recipe is rarely enforced, resulting the increase of components consumption. Nowdays, dry mixes are produced in factory conditions. They already contain all the necessary components in the correct proportions. Their preparation for applying is very easy: the right amount of water must be added. Industrial production of dry mixes stepped forward when one started adding polyvinyl acetate glue or PVA. Humanity became acquainted with polymer-modified dry mixtures. The advantage of adding the polymer solution is obvious: during the solidification of the mix, glue forms flexible connections between solid particles. They compensate tensile load on itself. A similar function is in steel reinforcement in concrete. These special additives or compounds impart special properties of finished mix: increased bond strength of materials, elasticity, i.e. the ability to resist expansion and contraction with changes in temperature, moisture resistance, water resistance and resistance to mechanical stress. Modification of building mixtures produced by cellulose ethers, redispersible powder and other additives, which significantly affects the physical and mechanical properties of the solutions. Additives can achieve such properties that ordinary mortars cannot demonstrate. Special rheological properties of such mixtures should be given as plaster, putty and tile adhesives. Important and high elasticity adhesive characteristics solidified thin slurries. As a rule, construction mixtures obtained from the dry mortar, made up of many components with different rheology. Solids solution at external forces are acting not only on the working tool, but also on attractive and repulsive forces, which depend on the type and dosage of modifying additives, physical and chemical properties of cement and aggregates. Attractive forces are formed, for example, of van der Waals, electrostatic and capillary. These forces give rise to flocculation and agglomeration, which changes the pattern of viscosity, usually increasing it [1]. As it is known, dry mixes from the viewpoint of colloidal chemistry are dispersion systems. Dispersive systems with the ability to form a solid structure, physical properties occupy an intermediate position between the liquids and solids, approaching one way or another depending on the degree of development and the strength of the structural grid. The presence of structure gives dispersion unique mechanical properties. These characteristics flexibility, strength, ductility, toughness