CC BY
6
SRSTI 666.974
https://doi.org/10.48081/WDGE4863
*S. ^ Akimbekova1, Zh. D. Ospanova2, G. I. Yakubovskaya3
1,2,3Toraighyrov University, Republic of Kazakhstan, Pavlodar
WAYS TO MANAGE THE QUALITY OF NANOCRETE
This article presents an integrated approach to the design of the concrete composition, which contains a combination of various types of modification of the concrete mixture by introducing a hyperplasticizer based on polycarboxylate ether, as well as reinforcing fibers (anisotropic additive), activation of aggregates, binders and mixing water. It is shown how the reinforcement of concrete cement stone with fibers reduces the formation of shrinkage cracks and increases its frost resistance, and polycarboxylate nanoparticles significantly reduce the amount of water used and the drying time of the material, making the steam treatment stage optional.
The article presents the mechanism of action of the hyperplasticizer, the test results of samples-beams and samples-cubes at the age of 28 days, as well as the result. As a result of the action, polycarboxylate particles are adsorbed on the surface of cement grains, repel each other and set the cement mortar in motion. With the help of this approach, a condition is created for the formation of a cement stone nanostructure of various functional actions with the help of nanoparticles already at the initial stage of mixing.
Keywords: concrete, nanotechnology, durability, structure, superplasticizer, fiber, hyperplasticizer.
Introduction
Currently, nanotechnology in the production of concrete allows for local stimulation of chemical reactions at the molecular level, changing the properties of traditional structural materials by modifying them with nanostructures, increasing strength, water and corrosion resistance.
One of the most important in the technology of nanobetons is the directed use of the process of self-formation of cement stone (in cement concretes), launched by nanoparticles specially introduced into the composition of concrete-nanoinitiators, either containing some compounds that initiate a special growth of cement stone, or possessing stable anisotropy of electrophysical properties, also causing the directed development of cement stone during concrete maturation. Nanocrete has these or other advantages due to its special structure set at the nanoscale [1].
The structure and properties of concrete are primarily determined by the quality of the cement stone. Which, accordingly, leads to the need to form a cement stone structure that will have a high density, low water permeability, high strength, frost resistance and corrosion resistance [2].
Materials and methods
To improve these properties, an integrated approach to the design of the concrete composition is required, which will contain a combination of various types of modification of the concrete mixture by introducing a hyperplasticizer based on polycarboxylate ether, as well as reinforcing fibers (anisotropic additive), activation of aggregates, binders and mixing water.
One of the ways to improve the properties of concrete is dispersed reinforcement with fibers (fiber) of various origins, such as polypropylene, steel, glass, basalt, synthetic, carbon and others. Reinforcement of concrete cement stone with fibers reduces the formation of shrinkage cracks and increases its frost resistance [3, 4].
The polycarboxylate ether-based hyperplasticizer is superior to traditional superplasticizers in reducing the amount of water, preserving workability, shrinkage, not to mention other parameters. With the help of the new technology, it is possible to create polymers for different types of cement, but this also means that each polymer structure behaves differently in different cements [5].
Results and discussion
It should also be mentioned about self-compacting concrete, which does not require vibration to consolidate the composition. Its use significantly reduces energy and labor costs. The starting material containing highly dispersed polycarboxylate nanoparticles behaves like a thick liquid with a small cement-water ratio. When drying, the swelling particles of the plasticizer prevent the formation of voids and cracks [6]. Self-compacting concrete has another important advantage. Conventional plasticized concrete slowly sets in winter, which leads to the need for additional steam treatment of structures. Polycarboxylate nanoparticles significantly reduce the amount of water used and the drying time of the material, making the steam treatment stage optional [7].
The mechanism of action of the hyperplasticizer is shown in Figure 1.
Cement particles in the initial period .Dispersed particles Hydrated particles
Figure 1 - Mechanism of action of polycarboxylate additive
The mechanism of action of the new superplasticizer is that polycarboxylate particles are adsorbed on the surface of cement grains and give them a negative charge. As a result, the cement grains mutually repel and drive the cement mortar. Only a small part
of the cement grain is coated with polymer and the free surface of the cement floccules are sufficient for water access and the hydration reaction. Note that the structure of polymers differ in the length of the main chain, the length of the side chains, the number of side chains and the ionic charge. Therefore, the properties of these polymers can be controlled by changing the molecular structure and directly affecting the properties of cement stone [8].
During the experiment, a control composition and formulations were made with the joint introduction of GP «Muraplast FK 63» with polypropylene fiber.
Figures 2 and 3 show data on the study of the effect of complex administration of the above-mentioned compositions of cement stone at the age of 28 days.
It should be noted that already at the daily age of the samples, an early set of strength, acceleration of hardening of cement stone, light stripping, smooth surface and smooth edges of the samples are noticed.
Figure 2 - Test results of beam samples at the age of 28 days
After analyzing the obtained values, it was found that with the introduction of polypropylene fiber modifiers in a percentage of 0,1 % (FcofM0.1) and Muraplast FK 63-0,5 % (by weight of cement), the bending strength of the beam samples increased by 25,7 %, and in a percentage of 0,2 % (FcofM0.2) - by 33,3 %.
Figure 3 - Test results of cube samples at the age of 28 days
As a result of the analysis of the obtained values, it was found that with the introduction of fiber in a percentage of 0,1 % (FcofMO.1) and Muraplast FK 63 - 0,5 % (by weight of cement), the compressive strength of the cube samples increased by 15,5 %, and with a percentage of 0,2 % (FcofM0.2) - by 12,2 % [9, 10].
Conclusions
Thus, by adding polypropylene reinforcing fiber together with the «Muraplast FK63» modifier to the cement mortar, a condition is created for the formation of a cement stone nanostructure of various functional actions using nanoparticles already at the initial stage of mixing.
At a later stage, when the cement stone has hardened and begins to shrink, polypropylene fiber fibers connect the edges of the cracks, thus reducing the risk of fracture. The use of fiber makes it possible to reduce the water separation of cement stone through effective hydration control, thereby reducing internal loads.
During the experiment, it was noted that polypropylene fiber is resistant to absolutely all chemicals that make up cement stone, to physical damage during mixing, is distributed evenly, without forming clots (when using a coffee grinder) throughout the entire volume of the composition and reinforcing it in all directions, does not lose its durability and appearance. Fiber is also compatible with any additives in cement composition and in concrete.
СПИСОК ИСПОЛЬЗОВАННЫХ ИСТОЧНИКОВ
1 Баженов, Ю. М. Модифицированные высококачественные бетоны / Ю. М. Баженов, В. С. Демьянова, В. И. Калашников // Научное издание. - М. : Издательство Ассоциации строительных вузов, 2006. - 368 с.
2 Касторных, Л. И. Добавки в бетоны и строительные растворы : учебно-справочное пособие / Л. И. Касторных. - 2-е изд. - Ростов н/Д. : Феникс, 2007. - 221 с.
3 Белов, В. В., Смирнов, М. А. Инновационные решения в технологии высокотехнологичных бетонов [Электронный ресурс]. - Режим доступа: http:// cdokp.tstu.tver.ru/site.services/
4 Базанов, С. М., Торопова, М. В. Самоуплотняющийся бетон - эффективный инструмент в решении задач строительства [Электронный ресурс]. - Режим доступа: http://www.бетонплюс.рф/samuplbeton.htm/.
5 ГОСТ 24211, ГОСТ 30459, ТУ 5745-013-51552155-2003. Muraplast FK 63. Гиперпластификатор для бетона, железобетона и предварительно напряженных железобетонных конструкций. 2003. - 2 с.
6 Добавки для бетона [Электронный ресурс]. - Режим доступа: http://www. nt-stroy.ru/dobavki-dlja-betona.html.
7 Баженов, Ю. М. Технология бетона. - М. : Изд-во АСВ, 2011. - 491 с.
8 Кудрышова, Б. Ч., Акимбекова, С. Т. Управление взаимосвязи свойствами цементного камня и качеством бетона. Сборник научных трудов IV Международной конференции школьников, студентов, аспирантов, молодых ученых / Ресурсоэффективные системы в управлении и контроле: взгляд в будущее. Т1. - Томск : 2015. - С. 31-35.
9 Саканов, К. Т., Акимбекова, С. Т. Пути управления качеством нанобетона. Сборник научных трудов IV Международной конференции школьников, студентов, аспирантов, молодых ученых / Ресурсоэффективные системы в управлении и контроле: взгляд в будущее. Т1. - Томск : 2015. - С. 26-30.
10 Кудяков, А. И., Ушакова, А. С., Тотай, С. Т. Управление качеством цементного камня бетона для дорожного покрытия. Международный сборник научных трудов/Новые технологии в строительном материаловедении. -Новосибирск : 2012. - С. 97-101.
REFERENCES
1 Bazhenov, Yu. M. Modified high-quality concrete / Yu. M. Bazhenov, V. S. Demyanova, V. I. Kalashnikov // Scientific edition. - Moscow : Publishing House of the Association of Construction Universities, 2006. - 368 p.
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4 Bazanov, S. M., Toropova, M. V. Self-compacting concrete is an effective tool in solving construction problems [Electronic resource]. - Access mode: http://www. бетонплюс.рф/samuplbeton.htm/.
5 GOST 24211, GOST 30459, TU 5745-013-51552155-2003. Muraplast FK 63. Hyperplasticizer for concrete, reinforced concrete and prestressed reinforced concrete structures. 2003. - 2 p.
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Material received on 06.06.22.
*С. Т. Акимбекова1, Ж. Д. Оспанова2, Г. И. Якубовская3
1,2,3ТораЙFыров университет^ Казахстан Республикасы, Павлодар к. Материал 06.06.22 баспаFа tyctí.
НАНОБЕТОННЬЩ САПАСЫН БАСЦАРУ ЖОЛДАРЫ
Бул мацалада бетонныц цурамын жобалауга кешендi тэсш усынылган, онда поликарбоксилаттар эфирiне нег1зделген гиперпластификаторды, сондай-ац кушейтетт талшъщтарды (анизотропты цоспа), агрегаттарды, байланыстыргыштарды жэне суды белсендiрудi енгiзу арцылы бетон цоспасын тyрлендiрудiц эртyрлi турлертщ комбинациясы бар. Бетон цемент тасын талшыцтармен ныгайту швгу жарыцтарын азайтады жэне оныц аязга твзiмдiлiгiн арттырады, ал поликарбоксилаттыц нанобвлшектерi пайдаланылган судыц мвлшерт жэне материалдыц кептiру уацытын едэуiр азайтады, бул бумен вцдеудщ цажетсЬз кезецт жасайды.
Мацалада гиперпластификатордыц эсер ету механизмi, 28 кундт улгыер мен текшелердi сынаудыц нэтижелерi, сондай-ац цорытындылар келтiрiлген. Эсер ету нэтижестде поликарбоксилат бвлшектерi цемент тyйiрлерiнiц бетне адсорбцияланады, взара итершп, цемент ерттдкт цозгалысца келтiредi. Осы тэсшдщ квмегiмен араластырудыц бастапцы кезецтде нанобвлшектердi цолдана отырып, эртyрлi функционалды эрекеттегi цемент тасыныц нанокурылымын цалыптастыру ушт жагдай жасалады.
Кiлттi свздер: бетон, нанотехнология, бержтж, цурылым, суперпластификатор, талшыц, гиперпластификатор.
*С. Т. Акимбекова1, Ж. Д. Оспанова2, Г. И. Якубовская3
1,2,3Торайгыров университет, Республика Казахстан, г. Павлодар. Материал поступил в редакцию 06.06.22.
ПУТИ УПРАВЛЕНИЯ КАЧЕСТВОМ НАНОБЕТОНА
В данной статье представлен комплексный подход к проектированию состава бетона, который содержит в себе комбинирование различных видов модифицирования бетонной смеси за счет введения гиперпластификатора на основе эфира поликарбоксилатов, а также армирующих волокон (анизотропная добавка), активацию заполнителей, вяжущих веществ и воды затворения. Показано, как армирование цементного камня бетона волокнами уменьшает образование усадочных трещин и увеличивает его морозостойкость, а наночастицы поликарбоксилата значительно уменьшают количество используемой воды и время засыхания материала, делая необязательной стадию парообработки.
В статье приводится, механизм действия гиперпластификатора, результаты испытаний образцов-балочек и образцов-кубиков в возрасте 28 суток, а также результат. В результате действия частицы поликарбоксилатов адсорбируются на поверхности цементных зерен, взаимно отталкиваются и приводят в движение цементный раствор. С помощью данного подхода создается условие для формирования наноструктуры цементного камня различного функционального действия с помощью наночастиц уже на начальном этапе смешивания.
Ключевые слова: бетон, нанотехнология, долговечность, структура, суперпластификатор, волокно, гиперпластификатор
