Keywords: non-autoclaved aerated concrete

FOR THE STUDY OF PECULIARITIES OF STRUCTURE FORMATION OF COMPOSITE BINDERS FOR NON-AUTOCLAVED AERATED CONCRETE

https://doi.org/10.34031/2618-7183-2019-2-3-41-47
Abstract
The basis of the modern market of cellular concrete is autoclaved gas silicate. At the same time, non-autoclaved aerated concrete is largely a more technological material, allowing the variation of its properties within a wide range, having a potentially wider field of application, less costly in the organization of production, which is of great importance for small and medium-sized businesses. The main problem of non-autoclaved aerated concrete is a higher cost of raw materials compared to silicate, and 20...30% lower strength performance. The proposed solution to this problem is the development of special composite binders with a limited content of clinker and mineral additives of various genetic types, taking into account the peculiarities of the two-stage structure formation of the material – gas porization and the formation of the microstructure of the stone. The article deals with some aspects of the interaction in the system “mineral additive – gypsum – by-products of the gas release reaction” in terms of the effect on the viscosity of the swelling mass and the strength of the stone at different times of hardening. Recommendations are given on the preferred compositions of composite binders and dosages of gypsum in the molding mixture when producing a material with an average density in the range of 500...700 kg/m3.
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ANALYSIS OF THE FACTORS OF INCREASING THE STRENGTH OF THE NON-AUTOCLAVE AERATED CONCRETE

https://doi.org/10.34031/2618-7183-2018-1-1-59-68
Abstract
Non-autoclaved aerated concrete is the only real alternative to gas silicate in the organization of its release on the basis of regional production of small and medium capacity. This will help improve the competitive environment in the building materials market and optimize the cost of construction. Of particular interest is the possibility of expanding the field of application of this material due to a significant increase in strength characteristics, while maintaining its average density in acceptable, in terms of thermal insulation properties, limits - not more than 1000 ... 1100 kg/m3. At a strength level of 10 MPa and above, in combination with dispersed reinforcement or the use of traditional non-metallic reinforcing elements, such aerated concrete can be used as a lightweight structural material for creating power elements of low-rise buildings, including in promising construction printing technologies; devices distributing the load belts; non-removable formwork; porous, stiffening, filling thin-walled tubular structures. The paper presents an assessment of the effectiveness of traditional ways to increase the strength of non-autoclaved aerated concrete. New solutions for the purposeful formation of the pore space structure are proposed and tested due to the creation and use of a gas generator with normalized gas evolution, which allows the creation of pores of a given volume. The key to the economic effectiveness of the proposed solutions is the transition from traditional portland cement to composite binders based on it. The substantiated choice of the amount and composition of the mineral additive makes it possible to optimize the properties of the binder under the particularity of the problem being solved, and to minimize the consumption of cement and chemical modifiers, increase the speed of durability and the final indices of non-autoclaved aerated concrete.
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