Modified fine-grained concrete for facing and repair of the hydraulic structures

Bazhenov, Yuri; Булгаков, Борис; Alexandrova, Olga V.

doi:10.1051/matecconf/20168603009

Cited by 6 publications

(4 citation statements)

References 4 publications

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“…Self compacting concretes (SCC) are widely used in construction practice due to the low labor intensity during production of concrete works [1][2][3][4][5][6]. Due to the high concentration of the mortar matrix, SCC poses high level of shrinkage and creep, and a reduced of E-modulus in comparison with traditional vibrational compaction concretes [5,[7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

On the Influence of Cross-Section and Reinforcement of Reinforced Concrete Constructions on the Concentration of Coarse Aggregate in Concrete with Frame Structure

Nesvetaev

Lesniak

Kolleganov

et al. 2020

MSF

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Concretes with frame structure produced by using the technology of separate concreting by immersing a coarse aggregate in a low-viscosity mortar matrix due to an increased concentration of coarse aggregate have an increased E-modulus, reduced creep coefficient and cement volume in concrete compared to traditional vibrational compaction concretes. Production concrete using separate concreting technology by immersing a coarse aggregate in a mortar matrix with low-viscosity allows to obtain a frame structure of concrete with a concentration of coarse aggregate up to 0.7 when a voidness of coarse aggregate is equal 0.28. The real concentration of coarse aggregate in a concrete structure depends on the particle size of the coarse aggregate, the cross-section dimensions of the structure, and the reinforcement coefficient. The influence of geometric dimensions and the coefficient of reinforcement on the concentration of coarse aggregate in the concrete with frame structure is studied. The concentration of coarse aggregate decreases with the growth of the S/V modulus (S – area, m2, V – volume, m3) and the reinforcement coefficient, but the decrease in the E-modulus does not exceed 5%. Conclusion: regardless of the type of construction and reinforcement, the concrete of the frame structure must have a sufficiently high uniformity of deformation properties.

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Section: Introductionmentioning

confidence: 99%

On the Influence of Cross-Section and Reinforcement of Reinforced Concrete Constructions on the Concentration of Coarse Aggregate in Concrete with Frame Structure

Nesvetaev

Lesniak

Kolleganov

et al. 2020

MSF

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“…Качественное бетонирование для таких конструкций является сложной задачей ввиду наличия труднодоступных зон в арматурном каркасе, затрудняющих равномерное распределение бетонной смеси в объеме возводимых конструктивных элементов. Применение мелкозернистых бетонных смесей литой консистенции или самоуплотняющихся бетонных смесей, позволяет не только обеспечить качественное бетонирование, но и эффективно применять бетононасосы различных видов, существенно сокращая трудозатраты на возведение сложных монолитных железобетонных конструкций [1,2].…”

Section: Introductionunclassified

Structure and properties of fine concretes based on composite binders

et al. 2019

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Introduction. Wide introduction of fine concretes in the practice of monolithic building construction is limited by their low crack resistance due to considerable shrinkage. To reduce the shrinkage adverse effect on structure and properties of the fine concretes, it is suggested to use for their preparation composite binders, including expanding sulphoaluminate-based cements. Using the fine concrete with enhanced physical and technical properties improves produceability of construction, reduces labor input of concrete casting and allows building installations of complicated architectural forms. Material and methods. To study processes of fine concrete structure formation and properties, concrete mixes were prepared on the base of medium silica sand, dispersed ash entrainment and expanding additive. Activity of the ash entrainment increased at the expense of mechanical and chemical activation. Dispersity of the particles was monitored by means of laser granulometry. The composite binder was prepared by means of thorough homogenization of the basic CEM 42.5 Portland cement and different sorts of mineral aggregates, including an expanding additive based on calcium sulphoaluminate. Maturing conditions at a certain moisture content were simulated for every composition with subsequent evaluation of concrete performance. Results. Results of the study include effect of different mineral additives distinguishing in mineral composition, dispersivity and degree of hydraulic activity on shrinkage amount and kinetics, fine concrete porous structure parameters and strength. It is understood that amount of expansion has an effect on porous structure characteristics of the fine concrete and its strength performance. The study assessed an influence of maturing conditions on the various-composition fine concrete. A considerable influence of maintaining optimal moisture content during hydration on fine concrete technical properties is committed. Conclusions. It is understood that introduction of up to 10 % of expanding sulphoaluminate-based component in basic Portland cement allows to obtain fine concrete with enhanced crack resistance, impenetrability and longevity.

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“…The effect of improving the quality of concretes with silica fume is greatly enhanced if silica fume is introduced in concrete mix as part of the complex with the superplasticizers or with additional organic-mineral additives that gives background chemical activation silica fume such additives [1,9]. In articles of chemistry and geology scientists have established experimentally that the amorphous silica may be dissolved in acid and converted into orthosilicic acid (H 4 SiO 4 or Si(OH) 4 , and in an alkaline medium to transfer to the sodium salt or orthosilicic acid of potassium [9,11]. Established that silica containing nanomodifier role can perform sol solution (H 2 SiO 3 ) met-silicic acid from soluble glass Na 2 SiO 3 .…”

Section: Introductionmentioning

confidence: 99%

Improvement of the modified heavy concrete properties based on the use of activated silica fume

Tkach

2019

E3S Web Conf.

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This article deals with the use of silica fume and ways of its activation to modify the structure of cement stone and concrete on its basis. With regard to any type of filler, namely silica fume, questions that are relevant: how to enter and how many, what mechanisms are involved in the process of structure formation, how much it costs achieved by the effect of modifying the structure and others. Formation of the answers to these questions require a systematic approach to vision problems. Therefore the role of microdispersed fillers in the modification process of the cement stone and concrete structures based on it must be considered together with other sized inclusions at different scale levels. The technology of synthesis of the complex additive based on ultrafine microsilica and superplasticizer “Plastilit RK” with characteristics allowing to use it as an effective additive in concrete has been developed. Studies have confirmed the effect of micro-silica fume in an acid medium (pH=2.1), enriched with oxonium H3O + ions, oxonium cations provide H+, and in an alkaline medium (pH=10-11), enriched with hydroxyl groups OH– - anions OH-, with obtaining dimers of orthosilicic acid Si (OH)4. It was shown that orthosilicic acid particles formed during the chemical dispersion of silica fume are additional crystallization centers, which allows speeding up the process of cement hydration.

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Modified fine-grained concrete for facing and repair of the hydraulic structures

Cited by 6 publications

References 4 publications

On the Influence of Cross-Section and Reinforcement of Reinforced Concrete Constructions on the Concentration of Coarse Aggregate in Concrete with Frame Structure

On the Influence of Cross-Section and Reinforcement of Reinforced Concrete Constructions on the Concentration of Coarse Aggregate in Concrete with Frame Structure

Structure and properties of fine concretes based on composite binders

Improvement of the modified heavy concrete properties based on the use of activated silica fume

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