Structure of artificial building materialsand its features
Abstract
Introduction. Structure consists of a binder, filler material and capillary-porous parts. These features are the kind of astringent that is used for the material, as well as in specific quantitative ratios of the binding and filler parts; in the nature of contacting these parts with each other on the surfaces of their section. The features, in addition, include a number of physical characteristics, the materials differ from each other - texture, color, weight, the ability of the structure to withstand the influence of thermal and mechanical factors, such as erasure, shock and static loads, high and low temperatures.
Goal. The aim is to study the types of astringent substances that determine the features of microstructure associated with the predominance of certain crystalline forms of tumors. For example, in the interaction of semi-aquatic gypsum with water, needle crystals of dihydrogen gypsum are formed, are closely interwoven with each other, and with age, solidification of gypsum stone increases in their sizes.
Methods of research. When hardening of Portland cement dough, tumors arise in various crystalline forms, which largely depends on the temperature of the medium and the concentration of calcium oxide hydrate in the liquid phase. The most characteristic is the formation of supersaturated solutions and geloid masses. They have crystallization centers that cause the formation of submicrocrystalline particles of calcium hydrosilicates, relatively large crystals of calcium oxide hydrate, hexagonal plates of calcium hydroaluminates, usually crystallize around C3A grains, other forms of tumors are isolated. When hardening of caustic magnesite, crystals of magnesium oxychloride grow in amorphous mass of magnesium oxide hydrate.The results of research. When hardening of the ceramic solution, crystalline mullite cemented with a glass of fusible eutectics is isolated. Similarly, microstructures of other hardened astringent substances are studied, which are studied by means of microscopic studies in reflected light, a set of optical characteristics, indicators of light refraction, the shape of crystalline grains, coloring, cleavage cracks, and others.The kind of filler material is rather vivid and directly characterizes the macrostructure of products, especially when studying the sills, it determines its physical characteristics. On the basis of the same binder, for example, Portland cement, products can be made with different fillers - dense crushed stone and sand in heavy cement concrete, porous gravel and sand in light cement concrete, asbestos in asbestos cement products, crushed wood and arbolit, wood wool in fibrolite, granular polystyrene in porous concrete, quartz sand in building solutions, etc.
Conclusions Thus, in addition to the aforementioned pores, the astringent parts may have relatively large spherical pores of the size from 50-100 μm to 2-5 mm, which are formed in different quantities depending on whether they are involuntarily or arbitrarily formed. If they arise due to spontaneous air involvement in the manufacture of a mixture of components, then their number is usually small (2-5%), but if they arise under the influence of special airborne or pore forming, burnt out during incineration, and other additives, then cropped in ' The tangent substance can concentrate up to 50% or more spherical pores, most often closed
