scholarly journals INFLUENCE OF ARTIFICIAL CALCIUM HYDROSILICATES ON THE HARDENING PROCESSES AND PROPERTIES OF NON-AUTOCLAVE SILICATE MATERIALS BASED ON UNCONVENTIONAL ALUMINOSILICATE RAW MATERIALS

2020 ◽  
Vol 3 (2) ◽  
pp. 19-28 ◽  
Author(s):  
A. Volodchenko
Keyword(s):  
Structure Formation ◽  
Building Materials ◽  
Raw Materials ◽  
Strength Increase ◽  
Isothermal Exposure ◽  
Moisture Treatment ◽  
Calcium Hydrosilicates ◽  
Clay Rocks ◽  
Heat And Moisture ◽  
Silicate Materials

one of the possible ways to improve the properties of building materials is to modify the processes of structure formation, which can be realized through the use of crystalline primers. In this regard, it is urgent to study the effect of artificial calcium hydrosilicates on hardening processes, as well as the properties of non-autoclave silicate materials based on non-traditional aluminosilicate raw materials. Studies have shown that the addition of artificial calcium hydrosilicates (CSH) in an amount of 1-1.5 wt. %, when the content in the mixture of CaO is less than 10 wt. %, effectively increases the strength parameters of products at all stages of heat and moisture treatment from 8 to 16%. The most intense increase in strength is observed during the heat-moisture treatment (TBO) from 3 to 6 hours and is at least 13%, while in samples without the addition of artificial calcium hydrosilicates, the strength increase is 6%. The addition of artificial calcium hydrosilicates intensifies the processes of structure formation, which ensures an increase in crystalline matter, and, due to the fibrous structure, acts as a fiber, which contributes to the nano-reinforcement of the cementing substance formed from neoplasms in the CaO-SiO2(Al2O3)-H2O system based on clay rocks and calcium oxide. Due to the accelerated set of strength, it is possible to reduce the duration of isothermal exposure while maintaining the necessary performance characteristics.

scholarly journals NON-AUTOCLAVE SILICATE COMPOSITES USING NON-TRADITIONAL RAW MATERIALS AND CRYSTAL FILLER

2020 ◽  
pp. 8-17
Author(s):  
A. Volodchenko
Keyword(s):  
Structure Formation ◽  
Raw Materials ◽  
Raw Material ◽  
Formation Processes ◽  
Product Density ◽  
Hardening Process ◽  
Calcium Hydrosilicates ◽  
Synthetic Crystal ◽  
Silicate Materials ◽  
Crystalline Growth

In the construction of buildings and structures, many wall materials are used, including silicate products of various functional purposes. In traditional production technology of such materials, the hardening process occurs due to the formation of a crystal structure in the CaO-SiO2-H2O system. There are various ways to modify the crystalline growth of the cementing substance, one of which is the use of various kinds of crystal seedings, in particular the use of natural and synthetic calcium hydrosilicates. The purpose of the experiments is to study the possibility of improving the performance properties of non-autoclave silicate composites by modifying the structure formation in the "lime-non-traditional aluminosilicate raw materials" system, which consists in the crystal-chemical regulation of the structure formation processes with a synthetic crystal filler CaO-SiO2-H2O (C-S-H). The use of synthetic crystalline filler C-S-H synthesized by hydrothermal synthesis in an autoclave at a pressure of 1 MPa and a temperature of 175 °C from a mixture of Ca(OH)2 and crystalline silica in a ratio different C/S=1 in the technology of non-autoclave silicate materials on the basis of alternative aluminium raw material allows to increase the operational indicators resulting products to 18 % or more. The optimal content of CaO and crystal filler C-S-H at which the maximum strength characteristics are provided is 8 % and 2.5 %, respectively, which allows to develop optimal compositions of raw materials for the technology of producing high-density non-autoclave silicate materials based on non-traditional aluminosilicate raw materials with a compressive strength of at least 20 MPa and more, with an average product density of no more than 2000 kg /m3.

scholarly journals WALL SILICATE MATERIALS OF NON-AUTOCLAVE HARDENING WITH THE USE OF SILICA RAW MATERIALS AND ALUMINOSILICATE BINDING BASED ON NON-CONVENTIONAL CLAY ROCKS

2019 ◽  
pp. 25-34
Author(s):  
А. Володченко ◽  
A. Volodchenko
Keyword(s):  
Building Materials ◽  
Raw Materials ◽  
High Energy ◽  
Structural Features ◽  
Average Density ◽  
High Pressure And Temperature ◽  
Production Technologies ◽  
Clay Rocks ◽  
Microstructure Of The Material ◽  
Silicate Materials

Among the used building materials, structural autoclave silicate products occupy one of the leading places. The traditional technology of silicate materials uses autoclave processing of products, the main disadvantage of which is the high energy intensity. In order to create non-autoclave silicate composites based on conventional siliceous raw materials, it is proposed to use a special aluminosilicate binder based on clay rocks of the incomplete stage of mineral formation of a certain genesis and quicklime. The strength of silicate materials is growing as a result of the neoplasm process. They are synthesized in the chemical reaction of quicklime with components of clay rocks when using high pressure and temperature modes in an autoclave, and when steaming with temperatures up to 100 °C. The high specific surface of the aluminosilicate binder provides an increase in the packing density of the material. Due to the structural features of the CaO-SiO2 (Al2O3)-H2O system based on unconventional clay rocks, the process of formation of the microstructure of the material, which continues and after hydrothermal treatment of the products, gives the material hydraulic properties. The proposed binders and their production technologies can be implemented in small and medium-sized businesses, which will allow to obtain competitive non-autoclave silicate materials with a compressive strength of up to 25 MPa and an average density of 1850 kg/m3.

Investigation of the Effect of Combined Binder Based on Portland Cement and Lime on the Properties of Non-Autoclave Silicate Materials Modified with Synthetic Crystalline Filler

2021 ◽  
Vol 1043 ◽  
pp. 127-132
Author(s):  
Aleksandr Volodchenko
Keyword(s):  
Portland Cement ◽  
Building Materials ◽  
Raw Materials ◽  
Mineral Formation ◽  
Hardening Process ◽  
High Temperature And Pressure ◽  
Reduced Parameters ◽  
Temperature And Pressure ◽  
Clay Rocks ◽  
Silicate Materials

Among the wide variety of currently used wall building materials and products, it is possible to single out the autoclave-hardened silicate products. To obtain silicate materials of autoclave hardening, lime-silica binders are mainly used. The hardening process of such a binder is carried out in an environment of water vapor at high temperature and pressure. It is relevant to use a certain type of silicate materials in the technology with raw materials that provide hardening with reduced parameters of hydrothermal synthesis, which will make it possible to obtain wall silicate materials in non-autoclave conditions. This can be done through the use of clay rocks of the mineral formation unfinished stage. In the course of the research, the effect of a combined binder based on Portland cement and lime on the properties of non-autoclave silicate materials modified with a synthetic crystalline filler was studied. It has been established that the addition of a synthetic crystalline filler represented by artificial calcium hydro-silicates makes it possible to increase the presence of a crystalline phase formed due to the clinker minerals hydration in the early stages of hardening, and, as a consequence, to increase the operational properties of the resulting composites. The addition of lime to the raw mixture will additionally compensate for the lack of calcium ions during the entire hardening process of non-autoclave silicate composites based on aluminosilicate raw materials and Portland cement.

scholarly journals Enhancement the Properties of Construction Urea Composition with Polymer Additive

2021 ◽  
Vol 2 (2) ◽  
pp. 1-8
Author(s):  
Arslanov Islom Kimsanovich
Keyword(s):  
Structure Formation ◽  
Building Materials ◽  
Chemical Resistance ◽  
Adhesive Bond ◽  
Alkali Resistance ◽  
Scientific Article ◽  
Strength Increase ◽  
Polymer Additive ◽  
Water Binding ◽  
Acid And Alkali Resistance

This scientific article provides physicochemical studies where the addition of a gel polymer has a positive effect on the process of structure formation. The presence of chemical bonds between the components, a change in the morphology of the structure, a decrease in microporosity, an increase in the density and thermal stability of the urea composition are shown. Polymer composite materials are used as chemically resistant coatings, polymer mortars and polymer concretes. Along with such valuable properties as incombustibility, colorlessness, good miscibility with water, etc., urea resins and compositions based on them have a number of disadvantages. The object of the study is a carbamide composition with a quartz filler and an addition of a gel polymer, its structure formation and chemical resistance. The methodological basis of the study is the polystructural theory of composite building materials (CBM) and the modeling of the study of the chemical resistance of the urea composition in aggressive conditions. The issues of finding effective water-binding additives and studying their effect on structure formation, properties and technology of urea compositions remain relevant and require additional research. It is shown that with the optimal content of the gel-polymer additive in the composition of 0.13% of the filler weight, the compressive strength and specific impact strength increase by 17; 13% and shrinkage is reduced by 7%. It was found that due to the enhancement of the adhesive bond between the components and the improvement of the pore structure under the action of the gel-polymer additive, the chemical resistance of the urea composition with quartz filler increases. So, water, acid and alkali resistance are 0.75; 0.80 and 0.85 and which, respectively, are 6, 7 and 7 points higher than the reference composition.

On the Issue of Reducing the Energy Intensity of the Silicate Composites Production with the Unconventional Aluminosilicate Raw Materials Use

2019 ◽  
Vol 974 ◽  
pp. 20-25 ◽  
Author(s):  
A.A. Volodchenko ◽  
Valery S. Lesovik ◽  
L.K. Zagorodnjuk ◽  
E.S. Glagolev
Keyword(s):  
Energy Saving ◽  
Building Materials ◽  
Energy Intensity ◽  
High Pressures ◽  
Raw Materials ◽  
High Reactivity ◽  
Raw Material ◽  
Green Technologies ◽  
Materials Used ◽  
Clay Rocks

The energy intensity of production of the most common wall materials in Russia is significantly higher than their foreign counterparts. The urgent task is to reduce the energy intensity of the production of building materials, to develop and introduce energy-saving nature-like technologies for the production of building materials, which corresponds to modern trends in the development of "green" technologies. It is possible to reduce the energy intensity of the production of silicate materials due to the transition from traditional raw materials to the use of unconventional aluminosilicate raw materials of various genesis, in particular, clay rocks of the unfinished stage of mineral formation. In the course of the research, the possibility of the synthesis of the new growth in the system “aluminosilicate raw material – calcium hydroxide – water” under the conditions of hydrothermal treatment was shown. Due to the high reactivity of the raw materials used, under the conditions of hydrothermal processing, the synthesis of tumors occurs not only at high pressures and temperatures, but also at temperatures up to 100 °C. This will allow to obtain efficient hollow-walled wall building materials using energy-saving technology.

Synthesis of Modifiers in the System Cao-Sio2-H2O and their Influence on the Non-Autoclave Silicate Materials’ Properties Using Aluminosilicate Binder

2020 ◽  
Vol 1011 ◽  
pp. 144-150
Author(s):  
Aleksandr Volodchenko
Keyword(s):  
Building Materials ◽  
Water Resistance ◽  
Pore Space ◽  
Crystalline Substance ◽  
Materials Properties ◽  
Clay Rocks ◽  
Increased Strength ◽  
Cementing Material ◽  
Crystallization Degree ◽  
Silicate Materials

Improving the hydration hardening building materials’ operational properties is possible due to the stable macro-, micro-and nanostructures’ creation by the cementing material crystalline aggregate directed modification, which can be achieved through the use of various additives acting as crystallization centers. In the course of the studies, the synthesized modifier effect nature represented by the system was revealed CaO-SiO2-H2O (CSH) on the properties of non-autoclave silicate materials using aluminosilicate binder of various compositions. It has been established that the use of an aluminosilicate binder together with the addition of a CSH modifier increases the presence of a crystalline phase at all stages of hardening, as well as intensifies the synthesis of low-basic calcium hydro silicates with a higher crystallization degree in the system CaO-SiO2(Al2O3)-H2O represented by lime and clay rocks. This contributes to the micro-reinforced crystalline framework formation of the neoplasms with increased strength. Due to this, the pore space decreases and the amount of synthesized crystalline substance increases, which helps to increase the water resistance of the samples in all compositions. The samples using an aluminosilicate binder and the addition of a CSH modifier achieve maximum strength with a CaO content of not more than 10 wt. % The optimal CSH modifier addition is up to 1.5 wt. %, with 7 wt. %, CaO content in a mixture increase in strength is up to 6%.

scholarly journals CALCULATION AND SELECTION OF THE HIGH DENSITY AGGREGATES FROM CONCRETE SCRAP

2020 ◽  
pp. 18-28
Author(s):  
W. Albo Ali ◽  
R. Lesovik ◽  
A. Kharkhadin ◽  
A. Tolstoy ◽  
A. Ahmed ◽  
...  
Keyword(s):  
Building Materials ◽  
Raw Materials ◽  
High Density ◽  
Internal Stresses ◽  
Cement Stone ◽  
Degree Of Hydration ◽  
Calcium Hydrosilicates ◽  
New Type ◽  
High Base ◽  
Selection Of

Abstract. The new transdisciplinary science of geonics (geomimetics) is the theoretical basis for designing construction composites from fragments of destroyed buildings and structures. Technogenic and natural anomalies, military conflicts on planet Earth lead to destruction of cities. Utilization of fragments of destroyed buildings and structures for the production of building materials is relevant. The classification and scheme of using fragments of destroyed buildings and structures to obtain crushed stone, sand, solutions and concretes based on them is proposed. The densest packaging is calculated using the method of selecting high-density filler packaging developed at BSTU named after V.G. Shukhov. The results are tested on the raw materials of destroyed buildings and structures in Iraq, which consist mainly of reinforced concrete, ceramic bricks and limestone blocks. The presence of binder particles that are not fully hydrated in the concrete scrap, which are subsequently hydrated and participate in the curing of the composite with the formation of an additional number of crystalline neoplasms, and also accelerates the hardening of cement stone and increases the final strength of the material. Subsequently, in the previously created structure, as a result of continuing hydration, a new type of system parts is formed, organized in a certain way, due to the crystallization growth of pico -, nano - and micro-sized high-base calcium hydrosilicates, depending on the degree of hydration of concrete scrap. The following crystallization of previously formed phases leads to self-sealing of different parts of the system and their further self-organization, which ensures high final strength and water resistance of the material. This hydration mechanism gives a concrete structure with minimal internal stresses and volume deformations. The article discusses the methodology for the selection of high-density packing of aggregate from concrete scrap in the destroyed building and construction of Iraq. It is shown that the strength of the obtained samples with compacted aggregate is 31.3 % higher than that of samples prepared in the traditional way.

scholarly journals Implementation of Contact-Condensation Hardening Theory Mechanisms when Forming Building Composites

2020 ◽  
Vol 24 (1) ◽  
pp. 90-102
Author(s):  
M. P. Stepanova ◽  
O. A. Sotnikova
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Structure Formation ◽  
Building Materials ◽  
Raw Materials ◽  
Raw Material ◽  
Material Base ◽  
Resource Saving ◽  
The Impact ◽  
Contact Condensation

Purpose of research is to study cheaper composite materials for building structures such as cement-free ones without heat treatment, which will undoubtedly allow finding their application in building industry. To achieve this goal it is necessary to identify patterns of structure formation of clinker-free contact condensation hardening composite materials in which portlandite crystals act as a matrix, and the physicochemical active component of natural origin acts as a filler.Methods. In accordance with the purpose set, one of the main tasks of the work was to be solved; it involved study-ing the patterns of structure formation of contact-condensation hardening systems relying on the basic principles of materials science, which include studying the influence of the composition, structure and state of the starting com-ponents on the properties of a composite material. In this work, we studied the role of the physicochemical activity of raw materials and the possibility of ‘combining’ a portlandite matrix with filling mechano-physicochemical active raw materials capable of producing new structures. To form the composite material, a compaction pressing technique at elevated specific pressures was used, which made it possible to implement the mechanisms of contact condensation technology of structure formation. The formation of physicochemical bonds of portlandite and aluminosilicate filler of various types is also possible with certain ratios of their mass fractions and V/I ratios the optimization of which was one of our objectives.Results. The result of this work is to assess the impact of raw material characteristics and technology parameters on the properties of the resulting material, namely, the improvement of the compacting pressure and the amount of filler when getting a compacted composite.Conclusion. The development of a technology of producing clinker-free contact condensation composites based on portlandite with aluminosilicate filler will expand the raw material base of local building materials, reduce their cost and energy consumption, that is, solve key issues of resource saving in the building materials production.

scholarly journals FEATURES OF THE STRUCTURE OF NEW GENERATION CONCRETE WITH THE USAGE OF ARTIFICIALLY-PRODUCED MATERIALS

2018 ◽  
Vol 15 (4) ◽  
pp. 588-595 ◽  
Author(s):  
A. D. Tolstoy ◽  
V. S. Lesovik ◽  
A. S. Milkina
Keyword(s):  
Structure Formation ◽  
Building Materials ◽  
Raw Materials ◽  
Experimental Studies ◽  
Construction Materials ◽  
High Strength ◽  
Standard Test ◽  
Cement Stone ◽  
Organic Additives ◽  
Test Procedures

Introduction. The important national economic task is to provide the modern construction industry with high-strength and effective materials made using new technological approaches and artificiallyproduced materials. These materials differ from the usual one by high content of cement stone, smaller grain size, multicomponent composition, increased specific surface of the filler. Therefore, the research of such problem would be always relevant according to the constant growth of requirements for the building materials and structures quality.Materials and methods. Experimental studies were conducted in the laboratories of the Department of Construction Materials, Products and Structures. The literary sources’ analysis was made in the scientific and technical library of the Belgorod State Technological University named after V. G. Shukhov. At the same time, standard test procedures and the provisions of the operating instructions for individual devices and equipment were used in the research.Discussion and conclusions. As a result, the models of structure formation in high-strength hardening compositions, in which the principle of structure optimization consisting in creation of the high degree ordering of its constituent elements and tumors, as well as in increasing the adhesion of cement stone particles, are implemented. In addition, the usage of artificially-produced materials and organic additives produces the possibility of reducing the consumption of raw materials and consumption of energy and resources. The mechanism and principles of structure formation management are intensively studied and would be explained later on the basis of synergetic concepts.

Investigation of the Synthesized Calcium Hydrosilicates Effect on the Properties of Energy-Saving Wall Silicate Blocks Obtained on the Basis of Technogenic Raw Materials

2021 ◽  
Vol 1043 ◽  
pp. 93-99
Author(s):  
Aleksandr Volodchenko ◽  
Valery Lesovik ◽  
Anatoly Volodchenko ◽  
Irina Cherepanova
Keyword(s):  
Energy Saving ◽  
Construction Industry ◽  
Raw Materials ◽  
Building Blocks ◽  
Average Density ◽  
Labor Costs ◽  
Calcium Hydrosilicates ◽  
Clay Rocks ◽  
Injection Technology ◽  
Technogenic Raw Materials

Currently, building blocks are widely used in the construction industry, the use of which contributes to an increase in the speed of construction several times, and also reduces labor costs. To obtain wall blocks, various binders are currently used, but the use of composite binders obtained on the basis of new types of raw materials, is relevant. Among the currently non-used natural raw materials, it is possible to single out aluminosilicate rocks, unconventional for the construction industry, characterized by the presence of clay rocks of mineral formation unfinished stage (aggregates) in their composition. Based on the results of the studies carried out, the effect of the synthesized calcium hydrosilicates addition was established as СSH (I) and С2SH(A) on the properties of energy-saving wall silicate blocks obtained on the basis of technogenic aluminosilicate raw materials. The rational content of the СSH (I) additive is 1.5 wt. %, which contributes to an increase in the products’ strength by 30-50%. The optimum lime content in the raw mix is 12 wt. %. The nature of the influence С2SH(A) on the properties of non-autoclave silicate materials obtained by the method of injection technology, in general, coincides with the addition of CSH (I). The resulting material can be used as a structural material (non-supporting structures) inside low-rise buildings and structures. Low average density of this material (1300–1450 kg/m3) indicates the best thermal properties (the thermal conductivity coefficient of the samples is 0.17 W/m·K).

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