Plakhotnikov K. Mineral thin-layer heat-insulating coating with increased physical and mechanical properties

The work is devoted to the development of the composition of the dry mixture to obtain a thin-layer insulation coating on Portland cement and fillers made of glass and aluminosilicate microspheres with high physical and mechanical properties. Object of study. Patterns of structure formation of heat-insulating material on Portland cement and fillers of aluminosilicate and glass hollow microspheres. The aim of the study. Development of a dry mix composition to obtain a thin-layer thermal insulation coating (TP) with high physical-mechanical and thermal insulation properties on Portland cement and fillers of aluminosilicate and glass hollow microspheres by modifying calcium binder and water retention. Research Methods. Experimental studies were performed using the method of planned experiment. Physical-mechanical researches are carried out in accordance with the normative documents of DSTU. The determination of the phase composition of cement stone and the microstructure of materials was performed by methods of physical and chemical analysis: infrared spectroscopy, electron microscopy. The novelty of the work is that it is theoretically substantiated and experimentally proved the possibility of increasing the physical and mechanical properties of thin-layer heat-insulating coating on Portland cement and fillers with hollow microspheres due to the micro-reinforcement of the cement matrix by the etching and the needle formation. by introducing additives of the second class of the third group (nitrates and calcium chlorides) and water-retaining additives; found that by using a complex chemical additive (CaCl2, Ca (NO3) 2, plasticizer "Melment F10", carboxymethylcellulose "Walocel") in the composition of the dry mixture to obtain a thin-layer thermal insulation coating on the basis of Portland cement and glass and aluminosilicate microspheres, achieved adhesive adhesion concrete base of 1.27 MPa, compressive strength of 1.53 MPa, flexural strength of 1.75 MPa, which is almost several times higher than the value of requirements for normative indicators for thermal insulation coatings; regularities of the mechanism of increasing the density of the structure of thermal insulation coating based on Portland cement and aluminosilicate and glass microspheres due to the formation of microfiber from etryngite needles on the surfaces of the microspheres and their interconnection due to electrogeterogeneous contacts; theoretically substantiated and experimentally confirmed by physico-chemical studies that the addition of salts of nitrate and calcium chloride in the composition of the dry mixture to obtain a heat-insulating coating based on Portland cement and aluminosilicate and glass microspheres, leads to the formation on the glass surfaces of needle hydroglycate in the form of fine fibrous crystals (felt), forming a microarray of the structure of the composite; applied the method of mathematical planning of the experiment, which allowed to find a rational ratio of carboxymethylcellulose ("Walocel" 0.05% - 0.09%) and components of the complex chemical additives (CaCl2, Ca (NO3) 2 1% - 2.8%.) in the composite based on Portland cement. The practical results are to obtain a mineral thin-layer thermal insulation coating (TP), which made it possible to perform an effective thermal insulation of enclosing structures in a thin layer; the economic effect from the application of the developed TP is achieved by changing the composition, reducing the thickness of the TP and constituting 28.8 UAH / m2 of protected surface (by the act of introduction in JSC "Trust Zhitlobud-1", Kharkiv); a technological scheme was developed for the composition of the TP and an experimental and industrial batch was issued at the enterprise of Center for Protective Technologies, Kharkiv, which was used for thermal insulation of buildings in Kharkiv (JSC Trust Zhytlobud-1); direction - construction.