Abstract: The article presents the results of the market research of dry mixtures produced in the Russian Federation. The established that glue dry construction mixes are in great demand. Information on the main produced glue dry mixes presented in the Russian market presented. The formulation of tile glue containing amorphous aluminosilicates as a modifying additive developed. The established that the synthesized aluminosilicates have a high activity equal to 350 mg/g. It has been established that samples of cement-based tile adhesive are characterized by high adhesion strength, which is more than Rkog = 1.4 MPa and Radg> 1.1 MPa. In the article carried out the estimation of technical and economic indicators of production of the adhesive dry mixes. The shown that the developed formulation of glue dry mixes is economically efficiency.
Abstract: Acute questions of steelfiber using for disperse-reinforced fine-grained concrete are considered in the article. Researchers of steelfiber concrete patterns are held. The efficiency of using crushing dropout of quartzitic sandstone is proven. The article studies the physical and mechanical characteristics of the filler. The chemical composition of the binder is presented. For dispersed reinforcement of fine concrete the influence of steel fibre on the strength characteristics of the mixture was studied. The characteristics of the fiber and the technology of obtaining a fiber-concrete mixture are presented. Studies showed the effectiveness of steel fibre with a percentage of 3% and a cement-sand ratio of 1/3.
Abstract: In the article the questions of application of a steel fiber for disperse reinforcing of fine-grained concrete are considered. Main filler of a fiber concrete mix was the KMA industrial sand enriched with sand. The carried-out researches showed advantage of a steel wave fiber before the anchor and flat milled. The optimal type of fiber is revealed, in which the greatest increase of strength and deformation characteristics is observed. Thus, it can be concluded that the type of steel reinforcing fiber and its shape have a significant impact on the length of building structures and buildings as a whole.
Abstract: The necessary fiber content in the first place is determined by the requirements of bending strength and resistance to dynamic loads. The fiber content depends on the composition and consistency of concrete, fiber properties and mixing techniques. The most widespread types of fibers, their advantages and disadvantages, possible areas of their application are considered. Fibers whose modulus of elasticity is greater than the modulus of elasticity of a concrete matrix, such as steel fibers or glass fibers, increase the workload on the cracks.
Abstract: The factors determining the production of fine-grained high-strength concrete are considered. The effect of micro-and complex nanodisperse additives based on natural mineral components, as well as the packing density of the quartz aggregate, on the strength parameters of fine-grained concrete is studied. The compositions of the fine-grained concrete modified by micro-and complex nanodisperse additives have been developed. The dependence of the fine concrete strength on the ratio of the mineral component and the stabilizer in the nanodisperse additive and the time of ultrasonic dispersion and additive storage is analyzed. The stabilization mechanisms of water dispersions of complex nanodisperse additives by various surface active modifiers are considered. The positive role of ultrasonic dispersion in obtaining nanodispersed additives is shown. The application efficiency of the micro-filler improving the density and strength of fine-grained concrete is revealed. The structure of fine-grained concrete is studied. It has been established by scanning electron microscopy that the introduction of the micro-and nanodispersed additives in the concrete leads to a less defective crystalline structure of the material.
Abstract: Paper observes research of the mechanical characteristics of the stabilized soil with different «Chimston» additives. Current work focuses on the application of the «Chimston-1» and «Chimston-2» produced by Zipo research and production company. Stabilized soil is based on local soils: argillaceous sand ground and sand clay. Chemical additives are mixed with water according to the manufacture’s recommendations. Amount of the «Chimston-1» is 0.07% of the soil. Amount of the «Chimston-2» is 0.01% of the cement. During the research plasticize effect is studied, based on maximum density and optimal humidity. Water saturation, mechanical strength under tension in bending and compression. It is established, application of the "Chimson" additives allow to increase key characteristics of the stabilized soil without increasing of the cement. «Chimston-1» additive has strongly pronounced plasticize effect which allow to increase soil compaction and decrease optimal humidity. Additive "Chimston-2" is a water repellent with a high degree of efficiency with soil stabilization.
Abstract: It is widely known that modern anionic surfactants are adsorbed at positively charged active centers of hydrate phases in portland cement that leads to floccules decomposition as well as a release of immobilized water, therefore increasing cement paste flowability. Normally, in cement based concrete such fine and coarse aggregates as quartz sand, granite, sandstone etc. are used. They contain negatively charged active centers, therefore, are inert to anionic water-reducing admixture and don’t affect fluidization of cement based concrete mixture. For instance, quartz sand with high concentration of fine particles as well as oxides and hydroxides of Al and Fe cations demonstrates a higher reactivity to anionic water-reducing admixtures. In order to increase the efficiency of anionic surfactants in concrete mixtures the treatment of aggregates with salts based on two-and three-valent cations was proposed. That provides a higher concentration of positively charged active centers on quartz sand surface leading to increase of flowability of concrete mixture.
Abstract: The comparative analysis of quality indicators of asphalt concrete and methods of their control is discussed in the present article. Classifications of modifiers for improving the quality of asphalt concrete are given. Novel nanoscale modifier for the improvement the resistance to climatic influences on asphalt is developed. The nanomodifier is based on sols of iron hydroxide and silicic acid. Nanomodification consists in processing of the mineral component by nanomodifier; such processing leads to the formation of nanoscale layer on the surface of the mineral carrier. As a mineral carrier we propose a highly porous mineral diatomite powder. The influence of the nanomodifier on the weathering resistance of asphalt concrete is investigated. Resistance to climatic influences was estimated by loss of strength after one nominal year of exposure. To simulate environmental impacts, an environmental chamber was used. The specimens were held in conditions that correspond to combination of summer and winter climate. One nominal year of exposure included 10 cycles of variable water saturation-drying at a temperature of 20 °C and 10 cycles of freezing-thawing (freezing was performed at –20 °C, thawing – at 20 °C). Saturation-drying and freezing-thawing duration was four hours. It was shown that by means of nanomodification the weathering resistance can be increased by 36 %.
Abstract: The paper considers the physicochemical activation of mineral powders used in asphalt concretes. Oil storage wastes, called oil sludges, are proposed to use as a surfactant. Activation of the surface of mineral powders is accomplished during the joint grinding of powder and oil sludge in a ball mill. As a result, the surface of mineral powders acquires hydrophobic properties; their physico-mechanical characteristics are improved: the reduction of porosity, bitumen content, and of the swelling index of asphaltic substances are observed. The introduction of activated powders into the composition of asphalt concretes can significantly reduce the amount of the required bitumen in the mixture. Decrease in water saturation index is detected in asphaltic concrete with activated mineral powders unlike in the test specimen. This implies an improvement in the index of resistance to atmospheric corrosion.
Abstract: The paper describes change patterns of colloid-chemical properties of mineral dispersions depending on the number of oxygroups in the aromatic ring of an elementary unit cell of oligomer molecules based on trifunctional oxyphenyls. It is proved that with the increase in the number of oxygroups within an elementary unit from 1 (phenol) to 3 (phloroglucine), the increase in plasticizing ability and plasticizing activity of oligomers is observed, while the plastic viscosity decreases due to the increase in water layer thickness between particles. Adsorption saturation of a surface layer with phloroglucinefurfural oligomers is achieved with smaller concentrations in the solution rather than with resocine-and phenolfurfural oligomers, which indicates the increase in binding energy of adsorbate with an adsorbent surface. The increase in repulsive forces is mainly caused by the formation of developed adsorption layers of oligomers on the surface of disperse phase particles and the increase in surface negative charge during adsorption of anion oligomers with one, two or three oxygroups within an elementary unit.