structure formation – Строительные материалы и изделия

Experimental studies of the processes of structure formation of composite mixtures with technogenic mechanoactivated silica component

https://doi.org/10.58224/2618-7183-2023-6-2-5-18

Klyuev A.V., Kashapov N.F., Klyuev S.V., Zolotareva S.V., Shchekina N.A., Shorstova E.S., Lesovik R.V., Ayubov N.A.

5-18 p.

Abstract

The paper considers the issues of utilization of technogenic fibrous material – waste of basalt production. The chemical composition of the technogenic fibrous material was studied, it was found that it consists of 44% SiO2. The initial basalt rock, which undergoes changes during high-temperature processing in the process of obtaining basalt fiber, was studied using IR spectroscopy. The grinding of the crowns was carried out for 30 minutes, allowing to reach a specific surface area of 800 m2 / kg. Further grinding does not lead to an increase in the specific surface area, which is associated with the phenomenon of secondary aggregation of fine particles. Research on REM has shown that the “cold shots” before grinding are mostly rounded or oval in shape. The compositions were formed and the strength characteristics of the samples for the 3rd and 28th day were determined. The maximum strength gain of 59 MPa was established at the age of 28 days in samples with the addition of 5% ground “cold shots” . When introducing cold shots in an amount of 10% (composition 5) of the cement mass, an intensive strength gain is noted in the early stages of hardening (7 days) with a strength of 38 MPa, slightly higher than the strength of the control composition. The introduction of 15% ground “cold shots” gives a strength value slightly lower (32 MPa) than the values of the control composition (37 MPa) at all stages of hardening.

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STRUCTURE FORMATION IN ALKALI ACTIVATED ALUMINOSILICATE BINDING SYSTEMS USING NATURAL RAW MATERIALS WITH DIFFERENT CRYSTALLINITY DEGREE

https://doi.org/10.34031/2618-7183-2018-1-4-38-43

Kozhukhova N.I., Strokova V.V., Kozhukhova M.I., Zhernovsky I.V.

38-43 p.

Abstract

The efficiency of traditional raw materials using as well as expanding of potential uses for non-conventional and alternative raw materials with different origin is the tasks exiting interest among material scientists and manufacture stuff. Investigation of the above is oriented on solution of such scientific problem as more deep understanding of structure and features of material. The results obtained also allow solution of some technological, technical and economical tasks.
Greatly, it is actual when using of new types of raw materials as well as when synthesis of new composites. Concerning the construction material science field, the classic problem is the looking for ways to study the reactivity of raw components under different conditions, its control and, generally, its increasing to produce higher performance materials.
Among the popular and widely-used construction materials are alkali-activated binders and relevant composites.
In this study the results of granulometric analysis of suspension based on alkali-activated aluminosilicate with different crystallinity degree are presented. It was found, when treatment of aluminosilicate grain by alkali activator leads to the grain solubilizing (but differently depending on crystallinity degree of aluminosilicate) and formation of alkali-aluminosilicate gel that reacts with unreacted part of the grain according to structure affinity principle. It was also determined the crystallinity degree of aluminosilicate component is inversely proportional to its solubility in highly-alkali environment. The model of structure formation for geopolymer system under alkali effect is offered.

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OPTIMIZATION OF RECEPTURAL-TECHNOLOGICAL PARAMETERS OF MANUFACTURE OF CELLULAR CONCRETE MIXTURE

https://doi.org/10.34031/2618-7183-2018-1-2-30-36

Alfimova N.I., Pirieva S.Yu., Gudov D.V., Shurakov I.M., Korbut Е.Е.

30-36 p.

Abstract

Aerated concrete at the moment is one of the perspective thermal insulation materials. However, the production of high-quality aerated concrete products is associated with a number of difficulties, primarily related to the features of the manufacturing technology and, in particular, to the formation of its structure during the period of gas evolution and the impact on this process of a large number of factors. The best conditions for the formation of cellular concrete are created when the maximum gas release and the optimum values of the plasticity-viscous characteristics of the aerated concrete mixture are found. Achieving optimal conditions is extremely difficult, which leads to a deterioration in the physico-mechanical characteristics of the final products. One of the ways to solve this problem is to increase the amount of mixing water, however, along with a positive effect (reducing the viscosity of the system), this leads to a decrease in the gas-holding capacity of the mixture. In this connection, the possibility of increasing the production efficiency of the cellular concrete mixture by optimizing the recipe-technological parameters was considered. With the help of the method of mathematical planning, a three-factor experiment was carried out, as the factors of variation were: the duration of the preliminary aging of the mixture, the dosage of the blowing agent and the water-hard ratio, the output parameters were the compressive strength and the average density of the final products. The obtained results made it possible to reveal the regularities of the change in the output parameters from the variable factors and to establish that the preliminary aging of the mixture before the introduction of the gassing agent positively affects the structure and, as a consequence, the physico-mechanical characteristics of the final products.

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