Abstract. The actual question of the production of porous aggregates for lightweight concrete is to increase their resource base through the use of materials of anthropogenic origin. While porous aggregates should be obtained taking into account the reduction of energy consumption, while addressing issues of disposal of industrial wastes.The purpose of this study -obtaining foam-glass-crystal porous aggregates for lightweight concrete, according to the technology of low-temperature foaming. The object of study was industrial waste production in Central Kazakhstan that contains silica and aluminosilicate components as the main component (slags, ashes of thermal power plants, tailings).The results of experimental investigations showed the possibility of obtaining foam-glasscrystal porous aggregates for lightweight concrete based on two-component and multicomponent mixtures composed of one kind of man-made materials, their mixtures in different ratios, and corrective additives. The paper discusses the two stage technology for obtaining foam-glass-crystal porous aggregates for lightweight concrete based on powder method, and includes two main stages: obtaining of will stekloagregat in terms of lowtemperature synthesis and preparation of the foaming mixture of glass powder with blowing agent, conducting a foaming process obtaining a final aggregate. The processes of formation of structure occur at lower temperatures (not above 900 0 С) compared with the process of obtaining foam glass and expanded clay with a significant reduction in the overall time of the technological process, which significantly reduces the energy consumption.The resulting porous aggregates are characterized by high physical and mechanical properties: density 200-220 kg/m 3 ; strength of 3.1-4.0 MPa; water absorption of 1-2%. Samples of lightweight aggregates are characterized by a high degree of homogeneity of the pore structure and is preferred for strength and conductivity pore sizes up to 1.2 mm and interporous partitions is 50 microns.Confirmed that the obtained porous fillers for light concrete unlike traditional fillers (agloporit, expanded clay), can withstand higher loads without degradation due to the presence of the crystal structure of interporous partitions. The material has a low water absorption compared to concrete block, that indicates the ability to maintain their thermal performance over time, and has virtually unlimited lifespan. For production of porous aggregate for lightweight concrete can be used in conventional industrial heating equipment used in the manufacture of bricks and ceramics.
Abstract. The purpose of these studies is to justify the feasibility of recycling different types of industrial waste instead of conventional expensive raw materials in production of environmentally friendly aerated concrete with required construction and operational properties. The impact of wastes from various industries on the environmental condition of affected areas, as well as the results of their environmental assessment were analyzed to determine whether these wastes could be used in production of high-performance building materials. The assessment of industrial wastes in aerated concrete production suggests that industrial wastes of hazard class IV can be recycled to produce aerated concrete. An environmentally friendly method for large-scale waste recycling, including a two-step environmentally sustainable mechanism, was developed. The basic quality indicators of the modified aerated concrete proved that the environmental safety could be enhanced by strengthening the structure, increasing its uniformity and improving thermal insulation properties. The modified non-autoclaved aerated concrete products with improved physical and operational properties were developed. They have the following properties: density -D700; class of concrete -В3.5; thermal transmittance coefficient -0.143 W/(m°С); frost resistance -F75.
This article deals with the use of silica fume and ways of its activation to modify the structure of cement stone and concrete on its basis. With regard to any type of filler, namely silica fume, questions that are relevant: how to enter and how many, what mechanisms are involved in the process of structure formation, how much it costs achieved by the effect of modifying the structure and others. Formation of the answers to these questions require a systematic approach to vision problems. Therefore the role of microdispersed fillers in the modification process of the cement stone and concrete structures based on it must be considered together with other sized inclusions at different scale levels. The technology of synthesis of the complex additive based on ultrafine microsilica and superplasticizer “Plastilit RK” with characteristics allowing to use it as an effective additive in concrete has been developed. Studies have confirmed the effect of micro-silica fume in an acid medium (pH=2.1), enriched with oxonium H3O + ions, oxonium cations provide H+, and in an alkaline medium (pH=10-11), enriched with hydroxyl groups OH– - anions OH-, with obtaining dimers of orthosilicic acid Si (OH)4. It was shown that orthosilicic acid particles formed during the chemical dispersion of silica fume are additional crystallization centers, which allows speeding up the process of cement hydration.
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