The effect of SiO2 nanoparticles derived from hydrothermal solutions on the performance of portland cement based materials

Flores-Vivián, Ismael; Pradoto, Rani; Moini, Mohamadreza; Kozhukhova, Marina; Потапов, В. В.; Соболев, Константин

doi:10.1007/s11709-017-0438-2

Cited by 44 publications

(25 citation statements)

References 12 publications

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“…Они могут действовать как центры, ускоряющие реакции гидратации, а так-же как нанонаполнители, повышая плот-ность бетона и уменьшая пористость [2][3]. Аморфная структура SiO 2 предопределяет его быстрое взаимодействие с Ca(OH) 2 в результате пуццолановой реакции (SiO 2 + CаО + Н 2 О→СаО•SiO 2 •Н 2 О) с об-разованием гидросиликатов кальция (ГСК) коллоидно-гелевой дисперсности [4].…”

Section: Abstract: Nanoparticles Sio 2 Cement Stone Portlandit X-unclassified

Research of Rare White Inclusions Composition in Pores of Cement Stone With Addition of Sol

Потапов¹,

Efimenko²,

Карабцов³

et al. 2018

СНТ (MHT)

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Выполнены эксперименты по модифицированию цементного камня (цемент -вода) наночастицами SiO 2 . Наночастицы SiO 2 вводили в цементное тесто в составе золя кремнезема, полученного по разработан-ной технологии на основе гидротермального раствора. Массовая доля SiO 2 составляла 1,15 % относительно расхода цемента, доза суперпластификатора 1,4 %, водоцементное отношение 0,26. Установлены пределы повышения прочности при сжатии модифицированного цементного камня. На срезах сечения образцов мо-дифицированного цементного камня обнаружены выраженные поровые включения белого цвета. Методами рентгенофазового и микрозондового анализов изучен вещественный и минерально-фазовый состав включе-ний. Белое вещество в поре представлено в основном кальциевыми соединениями в виде сросшихся и оди-ночных пластин и крупных призматических образований. Сделан вывод, что включения являются продуктом активного взаимодействия наночастиц SiO 2 с портландитом Ca(OH) 2 . Основной элементный состав белого вещества в поре: Ca, Si, Al, C и O. Состав характеризует наличие гидросиликатов, портландита и алюмина-тов кальция. Вероятно, это сгруппированные монокристаллы, сросшиеся в процессе гидратации, которые в электронном аналитическом пучке зонда дают смесевую картину. Результаты исследований важны с точки зрения механизма влияния наночастиц на характеристики модифицированного бетона. Experiments on modification of cement stone (cement-water) by SiO 2 nanoparticles were carried out. SiO 2 nanoparticles were introduced in cement paste by addition of sol obtaining from hydrothermal solution by developed technological regime. Dose of SiO 2 was 1.15 mas. % relatively cement expenduture, dose of superplistisizer was 1.14 mas. %, water cement relation was 0.26. Limits of rising compressive strength of modified cement stone were determined. On the cuts of section of modified cement stone samples expressed pores inclusions of white colour were found. By methods of X-Ray and microprobe analyses mater and minerals composition of inclusions were studied. White substance in pores is mainly of calcium combinations of plates grow together or in separate disposition and large prismatic formations. Conclision was made that inclusions are the product of active interaction of SiO 2 with portlandit Ca(OH) 2 . Basic element composition of white substance in pores: Ca, Si, Al, C and O. Composition of white substance includes presence such minerals as hydrosilicates, portlandit and calcium aluminate. Probably these are monocristals grouping grow together in hydration process which show mixed picture in electron analysed beam. Results of researchings are important from the point of view of mechanism of nanoparticles influence on characterestics of modified concrete.

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Section: Abstract: Nanoparticles Sio 2 Cement Stone Portlandit X-unclassified

Research of Rare White Inclusions Composition in Pores of Cement Stone With Addition of Sol

Потапов¹,

Efimenko²,

Карабцов³

et al. 2018

СНТ (MHT)

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“…The problem of stability of colloids recently begins to attract extra attention in materials science of building materials [1][2][3]. This is due to numerous efforts directed to the enhancement of building materials by means of nanotechnology [4][5][6][7], including application of modifiers that are based on so-called "primary nanomaterials" -1D/2D nanoobjects which were synthesized in predefined conditions outside of the composition [8][9][10]. Such objects can be multi-walled carbon nanotubes, nanoparticles of oxides -TiO 2 (in anatase form), ZnO, etc.…”

Section: Introductionmentioning

confidence: 99%

Modeling the colloidal dispersions: flocculation kinetics though particle dynamics

Smirnov

Korolev

2019

E3S Web Conf.

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The problem of stability of colloids recently begins to attract extra attention in construction materials science. This is due to numerous attempts to employ different kind of nanoscale modifiers for production of building materials with enhanced operational properties. Problems of stability and coagulation in colloidal dispersions are studied for several decades, and numerous results were already obtained within framework of Smoluchowski coagulation theory. In the present work we have performed numerical study of the flocculation process and compared the results with well-known ones. It was shown that even for complex pairwise potential the kinetics of number density for isolated particles is not very different from the kinetics which corresponds to constant coagulation kernel. However, for number density of many-particle aggregates we have observed number of peculiarities, including semi-periodic behavior.

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“…In nowadays practice of building materials production, the unconventional raw materials are used carefully after a large number of studies [1]. All this is fully applicable to industrial waste (metallurgical, electric-power, chemical, mining, etc.…”

Section: Introductionmentioning

confidence: 99%

Long-Term Water Saturation of Asphalt Binder Based on Fly Ash

Lebedev¹,

Kozhukhova²

2018

Proceedings of the International Symposium “Engineering and Earth Sciences: Applied and Fundamental Research” (ISEES 2018)

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The use of fly ash from power plants as a component of paving asphalt concrete has been studied by many scientists for over 100 years. However, there are conflicting data of their effect on properties of composites. The reason for this may be insufficient understanding of the role of fly ash composition, dispersity, structure and features of the structure formation process in asphalt compositions. The problem should be realized complexly. The current paper presents the detailed investigation of changes in the composition and structure of asphalt binder, occurred under continuously water saturation.Experimental studies show the asphalt composite from the mixture of bitumen, and high-calcium fly ash (FA1) is characterized by a significant decrease in the strength characteristics, an increase in volume of absorbed water and volume of specimens under long-term water saturation. The author have found that the reason for this is low adhesion of organic binder to surface of fly ash particles, therefore the bituminous film flushes, the active minerals of fly ash, such as tricalcium aluminate, lime, portlandite, anhydrite, react with water and form new phases of ettringite, calcite and gypsum, that makes the structure less compact. Low-calcium fly ash (FA2) with the best adhesion to bitumen forms asphalt binder during longterm water saturation the composite is characterized by low dynamics of increasing water adsorption and reducing of strength. The structure of composite material is more stable in comparison with other compositions. Thus, the composition and adsorption capacity significantly affect water resistance of composites. Keywords-fly ash from power plants, asphalt binder, water saturation, water resistance, new phases.

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The effect of SiO2 nanoparticles derived from hydrothermal solutions on the performance of portland cement based materials

Cited by 44 publications

References 12 publications

Research of Rare White Inclusions Composition in Pores of Cement Stone With Addition of Sol

Research of Rare White Inclusions Composition in Pores of Cement Stone With Addition of Sol

Modeling the colloidal dispersions: flocculation kinetics though particle dynamics

Long-Term Water Saturation of Asphalt Binder Based on Fly Ash

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