Structure and properties of fine concretes based on composite binders

Харченко, А И; Alekseev, Vyacheslav A.; Kharchenko, Igor; Bazhenov, Dmitriy

doi:10.22227/1997-0935.2019.3.322-331

Cited by 10 publications

(8 citation statements)

References 7 publications

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“…Hence, the control of the structure properties is nothing but the parameter variation of the Uo/Q. Nanoparticles in silica sol have a huge kinetic energy that allows them to act as active modifiers of concrete [1]. The application of nanodispersed silica as an additive implies introducing an additional nanostructured element in the concrete.…”

Section: Resultsmentioning

confidence: 99%

“…The improvement of the physical and mechanical properties of concrete by using nanosized materials with various functional properties plays an important role in the targeted regulation of hydration and structure formation processes of cement composites [1][2][3][4][5][6][7][8]. The particles with the sizes of 1-100 nm on the surface and in their bulk allow changing interatomic distances, and in some cases, atoms arrangement, that, in its turn, affects the properties of nanosized systems and modified materials [9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

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Fine-Grained Concrete with Nanodispersed Silica Additive

Лукутцова

Borovik

Pehen'ko

2020

MSF

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The effect of the modifying nanodispersed silica (NS) additive, obtained by the polycondensation method, on the properties of fine-grained concrete (FGC) is studied. It is revealed that the dependence of the NS-additive particle size on its age is extreme. The maximum number of particles of up to 100 nm in the additive is observed at the age of 10 days, and then their number decreases. However, it affects the FGC strength little even after 30 days of the additive storage. It is established that the NS-additive could be most effectively used with 0.23% of an active silica concentration and pH 4.1 in combination with S-3. At that, the porosity declines from 17.5 to 12.9% and the pore diameter diminishes from 3.171 to 0.689 μm. It leads to an increase in the compressive strength by 2 times and a decrease in water absorption by 1.6 times as compared to the control composition without additives. An increase in the frost resistance of the modified fine-grained concrete to F250 is recorded; it occurs due to a decrease in porosity at portlandite binding with amorphous silica additives into low-basic calcium hydrosilicates.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fine-Grained Concrete with Nanodispersed Silica Additive

Лукутцова

Borovik

Pehen'ko

2020

MSF

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“…The main objectives of modern construction are to reduce the time required for the manufacture of concrete and reinforced concrete products and accelerate the set of s tandard concrete strengths [1]. Several articles [ [2], [3], [4], [5]] discuss these problems in detail and analyze current solutions.…”

Section: Introductionmentioning

confidence: 99%

Effect of a complex modified additive based on post-alcohol bard on the strength behavior of concrete

Altynbekova¹,

Lukpanov²,

Dyussembinov³

et al. 2023

KIMS/CUMR/MShKP

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The article presents the third stage of the study results of a complex modified additive (CMA), in the accuracy of the influence of the variable ingredients of CMA on the strength of cement. This article shows the methodology of making samples, the selection of additive composition at different percentages of components, and the analysis of the strength behavior of the obtained results. To evaluate the changes in strength, samples were made and tested in compression and bending at 7, 14, and 28 days of normal-moist hardening. The results of the experiment showed that the addition of plasticizers (PAB) reduces the quantity of water - 35%, by increasing the strength of concrete by 20%. Compressive and bending strength results of the modified samples showed the best results, which were in the range of 42.80-63.66 MPa and 3.34-8.75 MPa, compared with the control composition. From the results of the research, the additive accelerates hardening and it was found that the additive contributes to the growth of strength, both at an early age and at the design age (28 days). The results of the experiment showed that from the standpoint of improving the qualitative characteristics of the samples, the use of plasticizers is appropriate. The use of CMA in the composition of concrete increases the strength, and therefore developed by the authors of CMA changes the structure of concrete and most importantly, increases the physical and mechanical characteristics of concrete.

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“…When using these diluents, it becomes possible to obtain concrete mixtures with different grades of workability. To reduce the negative impact on the structure and properties of concrete materials [15][16][17], there are several methods, including pretreatment of cement binder in full or in part with a superplasticizer at water-cement ratio from 0.5 to 1 and subsequent mixing with other components of the concrete mixture. This method was tested on the example of a concrete mixture consisting of cement in the amount of 376 kg/m3, crushed stone in the amount of 1105kg/m3, sand in the amount of 647 kg/m3, water in the amount of 210 kg/m3 and superplasticizer C-3 in the amount of 0.6% of the binder weight.…”

Section: Introductionmentioning

confidence: 99%

The use of superplasticizers in multicomponent concrete mixtures

Stenechkina

2023

E3S Web of Conf.

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In addition to the positive effect of the introduction of a superplasticizer, there are also negative ones: an increase in the period of structure formation, a significant air entrainment and, as a result, a decrease in strength. One of the ways to reduce the negative impact on the structure and properties of concrete composites is the method of preparing a suspension, which consists in first dissolving 10% of the amount of cement in all the mixing water in a concrete mixer for 1-2 minutes. Then load the rest of the cement and aggregate. Preliminary dissolution in water mixing with superplasticizer leads to the formation of a colloidal solution containing an increased amount of micro- and nanoparticles. When a superplasticizer is introduced into a cement-water suspension, particles with a high degree of dispersion are formed, as well as calcium hydrosilicate cristolites with a size of 1-3 nm. This sharply increases the activity of the superplasticizer and, consequently, improves the mobility of the concrete mixture. For example, from P2 to P3, from P3 to P5. This allows to reduce the consumption of the additive by 1.5 - 2 times. It has been established that the superplasticizer can be adsorbed only on hydrate neoplasms. For pre-treatment, it is necessary to use special equipment with high energy consumption such as RPA, fine grinding mills, disintegrators and various activators. Obtaining a cement-water suspension can be carried out in mortar, concrete mixers, in mixers of any type. The concrete mixture consists of cement, crushed stone, sand, water and superplasticizer C-3, determination of the draft of the cone using the Abrams cone, determination of the cubic strength using a hydraulic press in accordance with GOST 10180-2012. It becomes possible to increase the grade in terms of workability as a result of preliminary hydroactivation of the plasticizing additive, which leads to a decrease in its consumption. This method of hydroactivation of superplasticizers for the manufacture of cement concretes can be used to save the consumption of a plasticizing additive.

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Structure and properties of fine concretes based on composite binders

Cited by 10 publications

References 7 publications

Fine-Grained Concrete with Nanodispersed Silica Additive

Fine-Grained Concrete with Nanodispersed Silica Additive

Effect of a complex modified additive based on post-alcohol bard on the strength behavior of concrete

The use of superplasticizers in multicomponent concrete mixtures

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