Keywords: aluminosilicate raw materials

Efficient Silicate Composites of Dense Structure using hollow microspheres and Unconventional Aluminosilicate Raw Materials

https://doi.org/10.58224/2618-7183-2023-6-2-19-34
Abstract
One of the urgent tasks in the field of building materials science is to provide the construction complex with various types of environmentally friendly, reliable and energy-saving materials, the production and use of which will contribute to solving the problem of anthropogenic impact on the environment through the use of little-used technogenic raw materials. In the current conditions of import substitution, it is necessary to use the existing technological base to increase the volume of production of affordable, highly efficient, environmentally friendly traditional building materials, including using the existing raw materials base of the regions. In the market of building materials, structural wall materials of hydration hardening obtained using Portland cement as a binder are widely represented. However, silicate materials occupy not a small market share. It is known that pressed silicate materials of dense structure have fairly good strength indicators, but their thermophysical characteristics are low. A decrease in the average density of dense silicate products can be achieved by introducing various pore-forming components, such as hollow microspheres, into the raw material mass. The paper shows that the use of hollow aluminosilicate microspheres in the technology of obtaining silicate materials of dense structure based on unconventional aluminosilicate raw materials with energy-saving parameters of autoclave synthesis (water vapor pressure 0.4 MPa) and under conditions of heat and humidity treatment at atmospheric pressure allows to obtain a building composite with improved thermophysical and acoustic properties. Introduction to the raw mixture of aluminosilicate microspheres in the amount of 10-60 wt. % allows you to reduce the value of the average density index to 45%. The value of the compressive strength index of such samples, depending on the composition and hardening conditions, is 7-21.5 MPa at their average density of 920-1610 kg /m3, respectively.
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INFLUENCE OF ARTIFICIAL CALCIUM HYDROSILICATES ON THE HARDENING PROCESSES AND PROPERTIES OF NON-AUTOCLAVE SILICATE MATERIALS BASED ON UNCONVENTIONAL ALUMINOSILICATE RAW MATERIALS

https://doi.org/10.34031/2618-7183-2020-3-2-19-28
Abstract
Оne 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.
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