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Mazhidov Samariddin Rasheed coals., Senior teacher, Tashkent architectural and construction institute Samigov Nigmatdzhan Abdurakhimovich, Doctor of Engineering, professor Tashkent architectural and construction institute Toshken, Uzbekistan E-mail: [email protected]
RESEARCH STRUCTURIZATION of the CEMENT STONE WITH SDzh-3 SUPERSOFTENER ADDITION
Abstract. In the scientific article results of an experimental electronic microscope with use of concrete chemical supersoftener are generalized.
Keywords: Compound chemical additive, superplasticizer SDj-3, electromagnetic microscope for concrete.
Great demands for durability which, first of all, is estimated by frost resistance and water tightness are placed on the cement compositions (concrete, solutions, etc.) which are applied in hydrotechnical and road construction. The complexity of various and technical problems in a construction complex forms new tasks of improvement of compositions of concrete and construction solutions on the basis of cement compositions. One of solutions of similar tasks is creation and use of new complex chemical additives for cement compositions - the concrete mixes, construction solutions, etc. which are rationally combining necessary technical and operational characteristics [1, 64-71].
In recent years sharply the need for concrete on the basis of the cements with complex multicomponent modifiers meeting the requirements of modern construction increased. It is caused by the accruing trend of use of high-branded concrete, creation of new technical and constructive solutions, need of increase in reliability, durability and profitability of construction. Complex modifiers are a powerful tool of regulation and management of properties of concrete, including and monolithic. Introduction to structure of cement and concrete compositions ofvarious modifiers is the integral element of technology today. It is explained by an opportunity at rather small expenses to receive essential change of technological properties of concrete mixes and construction and technical properties of concrete [2, 111-125].
Among the main requirements imposed to high-quality monolithic concrete carry: high early durability and frost resistance, the high module of elasticity and stability of volume, low permeability in relation to water. Therefore the increasing attention is paid to researches surface-active additives ofthe air-involving action, actively affecting structural and rheological properties of concrete mix, structural porosity of a cement stone and also on a power condition of both the water environment,
and a firm phase of cement compositions. On the other hand the large volume of scientific research is executed by domestic scientists on a research of the fine mineral substances improving and regulating structural properties of concrete mix, such as fullness, nerasslaivayemost, water separation [3, 77-81].
Now there are no doubts any more and disputes on that is costs or you should not be engaged in a research and application surface-active and the struk-turoformiruyushchikh of additives. The issue is resolved as a result of accumulation of rather long and large-scale scientific practical experience. Use of modifiers of concrete for impact in the necessary direction on the processes happening in cement systems (cement dough, solution and concrete mixes, a cement stone, solution and concrete) from the moment of a zatvoreniye and before acquisition by it of the set properties is important means of improvement of technology of concrete. However the attention of scientists is required by questions of design of structure of complex modifications, development of selection criteria and assessment of chemical and mineral substances from positions of their synergetic action, the description of stability and bifurcations of the modified cement systems [4, 41-45].
Specific feature SDzh-3 is the fact that at presence SDzh-3a there is a formation of smaller crystal structure of a cement stone of normal curing.
The carried-out RFA of samples of the stone knitting showed what SDzh-3 has no impact on structure of hydrate phases. Processing of results of RFA allowed to reveal the following: introduction SDzh-3 at further water curing of samples causes education in a stone of the calcium knitting high-basic hydroaluminates which are found after 28 days of curing. Besides, are a part of hydrate phases high-basic C-S-Hc d/n GSC = 3.09; 2.85; 2.80; 2.00 1.83; 1.56; 1.40 À; Ca (IT) 2 with d/n = 3.11; 2.63; 1.79; À and also d/n which did not react alitc3ss = 2.74; 2.61; 1.77 À. At the age of 28 days
on roentgenograms of compositions from KJ - the 4th the main reflections of low main of GSC appear. After addition of KJ-4, the structure of the stone knitting at the age of 28 days is presented, generally C-S-H(II) with d/n = 2.85; 2.80; 2.00;
1.83; 1.56; 1.40 A; C-S-H(l) with d/n = 2.80; A; Ca (IT) 2 with d/n = 2.63; 1.79; A, ality with d/n = 2.74; 2.61; 2.16; 1.77; 1.62 A and also 2CaO-A12O3-8H2O with d/n = 2.68; 2.55; 1.75; 1.73; A.
a)
b)
a) control without additives; b) about superplastifkator SDzh-3 in number of 1% Figure 1.- Curve RFA of samples of the cement stone hardening under natural conditions.
Thus, at introduction SDzh-3 to cement composites, will allow to make active puzzolanovy and hydraulic properties of slag, to receive considerable gain of durability when using additives in optimum quantities and also to intensify hydration processes.
In drawings the complex structure of the cementing substance is presented. In the main gel mass of new growths the needle crystals of the ettringit filling free cavities are observed. New growths of the ettringit are formed in free volumes. In electronic microphotos of samples of a cement stone with complex additive filling of a time, both plaster, and calcium hydrosulfoaluminate is observed. Increase in concentration of hydrosulfoaluminate of calcium and increase in a specific surface of hydrate phases, both in the general structure of a cement stone, and in defective areas of a spatial skeleton, leads to material hardening.
The research of chips of the stone knitting at the age of 28 days in the electronic scanning microscope showed that when curing structure slag of the containing compositions block, consisting of GSC of different basicity and degree of a zakristallizovannost with inclusions of not reacted particles of slag and evenly distributed portlandit units (fig. 2.).
The structure of a stone without additives is put from coarse-crystalline educations high-basic GSC, with well za-kristallizovanny inclusions of the portlandit, a capillary time is observed.
The cement stone with SDzh-3 additive has non-uniform structure and is presented both by crystal hydrosilicates of calcium, and sites of C-S-H-of gel (fig. 2. a, b, g).
Gel areas, characteristic of stone, meet less often, are characterized by the relation of CaO/SiO2=2.5-2.8 and have tendency to crystallization that testifies to an intensification of hydration processes with addition of SDzh-3.
a)
b)
c)
a) control without additives; b) about SDzh-3 supersoftener in number of 0.8%; c) about SDzh-3 supersoftener in number of 1%; Figure 2. Electronic and microscopic pictures of samples of a cement stone
At application SDzh-3, to a dress from above the listed SiO2 relation = 2.6-2.8 surrounded with crystal new growths
characteristic new growths on a stone chip surface, gel sites from all directions.
of "uterine solution" with the high content of ions of calcium Thus, at introduction SDzh-3 to cement composites, will
appear. It is revealed that in this case the location of these areas allow to make active puzzolanovy and hydraulic properties
has not such character, as in the previous cases: they have the of slag, to receive considerable gain of durability when using
smaller size and represent small exits of C-S with with CaO/ additives in optimum quantities and also to intensify hydration processes.
References:
1. Koizumi K., Umemura Y., Tsuyiiki N. Effects of Chemical Admixtures on the Silicate Structure of Hydrated Portland Cement// Proceedings of the 12th International Congress on the Chemistry of Cement.- Montreal, 2007. P. 64-71.
2. Haehnel C., Lombois-Burger H., Guillot at alias L. Interaction Between Cements and Super plasticizers// Proceedings of the 12th International Congress on the Chemistry of Cement.- Montreal, 2007.- P. 111-125.
3. Karimov M. U., VafaevO. Sh., Dj alilov A. T. Study of the IR spectra obtained superplasticizer and its influence on the physico-chemical and physico-mechanical properties of the cement compositions // Journal "European applied science" - Germany.- No. 8.-2015.- P. 77-81.
4. Karimov M. U., Dj alilov A. T., Samigov N. A., Nurkulov F. N., ZokirovJ. Synthesis and application of plasticizing additives for cement // "Modern Problems of Polymer Science" Programm and abstract book of 9 th Saint - Petersburg Young Scientists Conference, November 11-14, 2013.- Saint - Petersburg,- P. 41-45.
