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KEY WORDS:
nature of hardening, lithifaction, aqua-complex, innovations, cement-free technologies
ABSTRACT:
Nature is the basis for the innovative development of building materials science. This has both physical (material-resource) and theoretical aspects. The latter refers to the geological process of lithification. During the lithification process loose sedimentary rocks turn into a rocky monolith, therefore lithification is a natural model of hardening when obtaining a concrete monolith. It is shown that the aqua complex [2SiO3- H2O − Mn+2Mm+Oˈ4], where Mn+− Na+ and other single and divalent cations, Mm+ - Al3+ and other multivalent cations, Oˈ-O and other volatile ions, is a solution to the problem of water–mineral unity in the process of mineral formation. This reveals the physico-chemical mechanism of setting, hardening and strength gaining in the technological system C – S – H. The concept of the aqua complex serves as a theoretical basis for saving raw materials and energy in the production of concrete with specified properties and composites based on it. One of the many practical confirmations of this concept is the possibility of using modern geophysical phenomena to develop cement-free technologies.FOR CITATION:
Stenina N.G. Natural resource for the innovative development of construction materials science // Technique and technology of silicates. – 2023. Vol. 30, No4. – Pp. 308-315.
ABSTRACT:
The aim of the work is to analyze the changes in physical and mechanical characteristics of silica sand during its single and multiple activation in an energy-loaded impact apparatus. The studies consisted of single (E17), double (E34) and triple (E51) activation of silica sand in a disintegrator apparatus with the energy used for activation of 17, 34 and 51 kJ/kg, respectively. According to the results of the obtained data, the change in wettability of activated silica sand particles was revealed, and the change in bulk density as well as hollowness of sand particles after activation was determined. The constructed differential distribution curve of sand particles with different energies spent on activation, as well as electron microscopy allowed us to judge about the nature of particle destruction and changes in the particle size distribution of sand before and after activation. It is shown that the shock character of sand particles destruction during its activation in the disintegrator leads to the fact that the particles acquire a splinter shape with sharp angles and strongly developed configuration. The obtained results show that with the increase in the specific surface area of sand during activation the concentration of active surface centers of quartz sand grains increases, but the density of active centers per unit surface area practically does not change.
FOR CITATION:
Samchenko S.V., Osmanov A.B., Abramov M.A. Activation of silica sand in a disintegrator plant // Technique and technology of silicates. – 2023. Vol. 30, No4. – Pp. 316-327.
KEY WORDS:
sulfoaluminate cement, fly ash, blast furnace granular slag, water demand, strength
ABSTRACT:
In order to improve the performance of cement and concrete and to reduce the associated CO2 emissions, both the development of new types of binders and the improvement of existing ones are needed. Specialty cements, in particular those containing calcium sulphoaluminates, are in great demand today. The introduction of various mineral additives to cement clinkers makes it possible to reduce the amount of expensive clinker in cement and change its properties. In this study, the effect of mineral additives - fly ash and blast furnace granulated slag on the properties of sulfoaluminate cement was investigated. Introduction of mineral additives into sulphoaluminate cement in the amount of 20% leads to reduction of water consumption up to 43 - 46,5 % against 62,5 for unadulterated sulphoaluminate cement, improves workability of fresh cement dough and concrete, prolongs setting time and increases flexural and compressive strengths. The best results are achieved with the compositions in which sulphoaluminate cement is replaced with 15% fly ash or 20% BFS, and the flexural strength at the age of 28 days was 13.1 MPa when 15% of fly ash was introduced, and 53.5 MPa in compression. The highest flexural strength (14.8 MPa) and compressive strength (68 MPa) is characteristic for sulfoaluminate cement with the addition of 20% BFS.KEY WORDS:
magnesium binder, magnesium oxychloride cement, dolomite, caustic dolomite, plasticizing additives.
ABSTRACT:
The article presents studies of the effect of plasticizing additives on the properties and structure of magnesia stone obtained from soft-burn binder. Compositions with plasticizers based on lignosulfonates, naphthalene sulfoformaldehydes and polycarboxylates in the amount of 0.25-1.5 wt.% to caustic dolomite were analyzed. According to the results of laboratory tests, the most effective concentrations of plasticizers were determined at which an increase in the strength of magnesia stone by 1.6 times was achieved, as well as a decrease in water demand by 11%. The analysis of magnesia stone mineralogical composition and morphology was performed by IR spectroscopy and XRD method. It was found that the modified magnesia stone contains the following components: undecomposed dolomite (40%), magnesium oxychloride (Phase 3) (15%), calcium carbonate (30%), quartz and graphite impurities of not more than 2 wt.%. However, plasticizing additives do not significantly affect the phase composition of magnesia stone, but increase its density and strength.KEY WORDS:
optimal composition, differentiated and integrated approaches.
ABSTRACT:
Modern tendencies in building material science are characterized by increased requirements to the quality of applied raw materials, production technology of building composites and operational properties of products. Obtaining of ecologically safe and at the same time economical composite building material is a complex multi-target and multi-parameter task. The external optimization problem is solved by conducting experiments, each of which includes fixing external variables of parameters, checking external constraints, solving the internal optimization problem and calculating the target function. Experiments differ in the values of external variables of parameters, which are changed from experiment to experiment in accordance with the algorithm defined by the rule. The solution of the internal optimization problem in this case is reduced to the calculation of reinforced concrete structure according to SNiP at fixed external variable parameters. This study formulates an integrated approach to the assignment of optimal compositions of materials of building structures, which consists in the assignment of compositions taking into account the requirements for both the properties of the material and the properties of the structures for which it is intended.KEY WORDS:
hydraulic concrete, Portland cement, vitreous perlite, composite binder, composition optimization, strength.
ABSTRACT:
The choice of binder providing a set of required physical and mechanical properties and having a moderate level of heat release is an important aspect in the selection of concrete composition for hydraulic structures. The problem of concrete optimization as a multicomponent system characterized by a significant number of interrelated parameters in conditions of incomplete knowledge of the mechanism of interaction of mixture components can be solved using experimental and statistical methods. The purpose of this research is to optimize the composition of hydraulic concrete by mathematical planning of the experiment when varying the components of the concrete mixture according to the criterion of high physical and mechanical performance. The article presents the results of research on the use of composite binder based on Portland cement and vitreous perlite for concrete hydraulic structures. A differential thermal analysis of Portland cement and composite binder was carried out, indicating a change in the degree of hydration of the cement system and the formation of an additional amount of low-base calcium hydro silicates. A three-factor experiment was planned and carried out to optimize the composition of hydraulic concrete according to the criterion of compressive strength of concrete at the age of 28 days. According to the results of three-factor planning, it was found that the composition with a cement content of 425 kg is optimal. The introduction of vitreous perlite with a specific surface area of 600-800 m2 / kg in an amount of 10-20% by weight leads to an increase in the compressive strength of hydraulic concrete by 20-25% compared with the control additive-free composition.KEY WORDS:
acoustic sound absorbing materials, hogweed Sosnowski, sound absorption coefficient, gypsum binder, carbon footprint, renewable raw materials.
ABSTRACT:
The use of plant-based raw materials provides the construction materials industry with a rich source of low-cost, environmentally friendly raw materials, often already prepared. In this article, the object of the study is an organominer composite based on gypsum binder and dispersed borscht Sosnovsky. The physical-mechanical and acoustic properties of the composite have been studied. The limit of bending strength was determined on the samples «beams» with dimensions 40 40 160 mm. and the tensile strength of the compression on the samples of the «halves» obtained after the determination of Rизг. The sound absorption coefficient was determined according to the method applied to GOST 16297-80 Materials are soundproof and sound absorbing. Test methods Thus, the bending strength is between 0.4 and 0.9 MPa and the compression strength is between 1.2 and 1.68 MPa (depending on the density of the composite (from 400 kg/m3 to 800 kg/m3)). The sound absorption coefficient for frequencies from 2000 Hz to 6300 Hz is between 0.74 and 0.85 (for a 500 kg/m3 sample) and 0.4-0.72 (for a 700 kg/m3 sample). Use of Sosnovsky in construction production allows to obtain environmentally friendly materials.KEY WORDS:
technical hemp bonfire, lime binder, sodium caseinate, restoration, white stone masonry, silicon dioxide.
ABSTRACT:
The article is devoted to the study of composite materials for the restoration of white stone masonry monuments of architecture of the XII-XIX centuries. The paper studies the properties of masonry materials of carbonate rocks and develops compositions using lime binder and filler: fires of technical hemp as a reinforcing component that allows to increase the bio-resistance of masonry materials. Compositions of composite materials similar in their microstructure to the materials being restored have been developed. Silicon dioxide, sodium caseinate, diatomite, marble chips and a plasticizing additive were used as modifying additives. The resulting composites have not only structural similarity with the restored material, but also high performance characteristics that ensure the durability of the restoration object, such as compressive strength-7.2-8.3 MPa, bending strength-3.1-4 MPa, adhesive strength-0.56-0.6 MPa and frost resistance coefficient-0.65. The technical hemp proposed as a fire filler (8-12%) provides, in addition to mechanical strength, high biological resistance, since it is not exposed to fungal micro-organisms, which makes it more environmentally attractive compared to many natural materials. The developed composites can be used on restoration objects as pre-composite and masonry compositions. Due to the fact that the cost of technical hemp bonfires is quite low and amounts to 8 rubles / kg, it allows you to reduce the cost of the composite, but at the same time maintain strength characteristics and ensure porosity corresponding to limestone.KEY WORDS:
modified binder, Portland cement, volcanic tuff, analytical optimization, plastic shrinkage, concrete textiles.
ABSTRACT:
The designing of modern building materials and structures, united by the common name textile concretes, allows to significantly reduce the thickness of products, and, consequently, their mass and material consumption of structures, when achieving standard characteristics. The basis of such products are fine-grained concrete on a hydraulic binder, which involves the use of special optimized compositions, while there is a danger of deformation of products an early hardening age, and, as a consequence, the crack formation in the volume of hardening material. The purpose of this research was to develop and optimize the composition of a modified binder for products and structures of small thickness, such as textile-reinforced concrete, concrete fabric and reinforced plaster coatings for facade finishing. The experiment, conducted using methods of mathematical planning, statistical processing of results and analytical optimization, allowed us to develop the basics of a methodology for predicting the properties of a modified binder and selecting its composition. As a result, the following characteristics of the modified binder were obtained: content of Portland cement 320 kg/m3; content of volcanic tuff 80 kg/m3; cellulose ether 4.48 kg/m3. Finely ground volcanic tuff has a water absorption of 8-12% and, together with cellulose ether at the stage of preparation of the mixture, immobilizes part of water that it gives off during hardening, thereby compensating its possible deficiency. This makes it possible to obtain a modified binder with the following characteristics: compressive strength of 50.2 MPa; average density of 1665 kg/m3; water content of 0.387.