RU2667180C1 - Method of preparing concrete mixture - Google Patents

Abstract

FIELD: construction.SUBSTANCE: invention relates to the field of construction, namely to methods for preparing a concrete mixture and mortar, concrete and structures and can be used in the technology of production of products and structures in prefabricated housing construction and in monolithic construction. Method of preparation of a concrete mixture includes the treatment of a solid cement binder with a vortex layer of anisotropic ferromagnetic bodies in a nonmagnetic vessel located in an apparatus with an external electromagnetic field. Binder together with the carbon nanotubes and the superplasticizer in the form of a powder are fed through a rotating screw through the inner cavity of the non-magnetic continuous tube to the zone of rotating anisotropic ferromagnetic bodies with a diameter of 1.2 mm and a length of 5–10 mm, having an energy saturation of the working zone of at least 100 kW/m, the motion of which is provided by the apparatus with an external electromagnetic field.EFFECT: technical result is an increase in the mobility of the concrete mixture, increase in the early and vintage strength of concrete products for compression.1 cl, 1 tbl

Description

The invention relates to the field of construction, and in particular to methods of preparing concrete and mortar mixtures, and can be used in the technology of production of products and structures in prefabricated housing construction and in monolithic construction.

A known method of preparing a concrete mixture in which 50% of the estimated amount of cement is mixed with mixing water containing 50% of the estimated amount of superplasticizer based on polycarboxylate ether - REMICRETE SP11 - and TUBALL single-walled carbon nanotubes is subjected to mechanochemical activation in a rotary pulsation apparatus with the number of revolutions of the working rotor body 5000 rpm for 2-3 minutes, followed by mixing the remaining part of the cement, aggregate and the rest of the superplasticizer - REMICRETE SP11 - in the concrete mixer for e is not less than 5 minutes. The technical result is an increase in the mobility and preservation of the concrete mix, an increase in the brand strength of concrete (RU 2608830 C1, publ. 01.25.2017, bull. No. 3).

The disadvantage of this invention is the low strength of the resulting concrete, the complexity of the equipment, as well as the technical complexity of the process of preparing the concrete mixture.

A known method of activation of a binder material (cement, lime, gypsum) of building products, including obtaining a cement-air mixture in the spray chamber, feeding it into the charging chamber, where monopolar ionization and shaking is carried out. The camera is made of a dielectric, equipped with vertically mounted coaxial electrodes, shaking the electromagnetic field. Spiral electrodes provide ionization, and the electrodes in the center create an alternating electromagnetic field that enhances the shaking and mixing of the ionized air-cement mixture due to eddy currents, as well as due to vibration of the electrodes due to their electromagnetic interaction (RU 2366510 B02C 19/18, C04B 40/00 published on September 10, 2009, Bulletin No. 25).

The disadvantage of this invention is the low strength of the obtained heavy concrete, low specific surface area of the cement, the complexity of the process of activation of cement, the difficulty of maintaining a stable technological process.

The prototype of this invention is a refractory concrete mixture and a method of manufacturing concrete from it, which consists in the fact that part of the components of the mixture in dry form, consisting of high alumina cement, mullite powder fraction of 50-100 microns, silicon dioxide nanoparticles and / or modified alumina, pre-treated with a rotating electromagnetic field in a device with a vortex layer in a sealed capsule for 100-140 seconds, with the ratio of the processed components of the mixture and ferromagnetic particles (2-4): 1, ATEM remaining components are added and the mixture was shuts water. The sealed capsule is made of non-magnetic carbide material. The magnetic field strength of the apparatus with a vortex layer is 0.18-0.22 T (RU 2530137, C04B 35/66, C04B 28/06, C04B 35/626, publ. 10.10.2014, bull. No. 28).

The disadvantage of this invention is the low early and grade strength of the resulting concrete.

The objective of the present invention is to increase the mobility of the concrete mixture, increase the early and grade strength of concrete products in compression.

The result is achieved in that in a method for preparing a concrete mixture, including preliminary activation of a binder together with carbon nanotubes and with a superplasticizer in the form of a powder, a cement binder is fed through a rotating screw through an internal cavity of a non-magnetic continuous pipe into a zone of rotating anisotropic ferromagnetic bodies with a diameter of 1.2 mm and 5-10 mm length having energy saturation working area of at least 100 kW / m ^3, the movement of which provides a device with an outer electromagnetic field, hereinafter aktivirova Noe binder is mixed with large and small filler shut water and the mixer is further stirred for at least 5 min.

The invention is illustrated by the following example.

For the preparation of the concrete mix of the production composition, M400 PC D20 cement of the Ulyanovsk plant was used, which meets the requirements of GOST 31108-2003, sand of the Kama-Ustinsky field, which meets the requirements of GOST 8736-93 and GOST 8735-88, and crushed stone of the Kamsko-Ustyinsky field, which meets the requirements of GOST for concrete , in the following ratio (mass hours): cement: sand: gravel = 1: 1.13: 2.68. Consumption of cement per 1 m ^{3 of} concrete amounted to 490 kg.

The activation of cement together with carbon nanotubes and a superplasticizer was carried out in the vortex layer apparatus for 5-8 minutes using metal fibers as cylinders with a diameter of 1.2 mm and a length of 5-10 mm as ferromagnetic particles. Moreover, the energy saturation of the working area of the apparatus was not less than 100 kW / m ³ .

As a superplasticizer used additive C-3 in the form of a powder, manufactured according to TU 5745-001-97474489-2007 in an amount of 1.0-1.5% by weight of cement.

OCSIAL TUBALL single-walled carbon nanotubes in the amount of 0.0005% by weight of cement, meeting the requirements of TU 2166-001-91735575-2014, were used as carbon nanotubes.

Activated cement was mixed with coarse and fine aggregate, closed with water and further mixed in a concrete mixer for at least 5 minutes.

Samples — cubes with sizes of 10 × 10 × 10 — were made from concrete mixtures. After 1 and 28 days of normal hardening, the samples were subjected to mechanical tests. The strength of the samples was determined in accordance with GOST 10180-2012. The specific surface area of the initial, activated and prototype cement was determined on a PSX-9 device.

The results of physical and mechanical tests of the samples are shown in table 1.

Table 1

No.
p / p Activation time, sec. W / C OK,
cm Wednesday raft.
concrete
kg / m ³ Compressive strength at the age of 1 day., MPa Compressive strength at the age of 28 days, MPa one - 0.37 9 2485 7.2
one hundred% 45.4
one hundred% 2 300 0.37 22 2490 24.86
345% 73,4
162% 3 480 0.37 twenty 2495 26.7
371% 74.9
165% four
(prototype) one hundred 0.37 10 2485 12,4
172% 54.9
121%

Note *: above the line is the average value of the indicator; below the line is the relative value of the indicator in% of the prototype.

From the data table. 1 it can be seen that the concrete obtained on the basis of activated cement allows to obtain compressive strength of heavy concrete 2.0-2.2 times higher in the first day of hardening, and 34-36% higher at grade age compared to heavy concrete, obtained by the prototype. In this case, the mobility of the concrete mixture according to the proposed method increases by 10-12 cm, as measured by the draft of a standard cone according to GOST10181-2014.

Claims (1)

A method of preparing a concrete mixture, comprising treating a solid cement binder with a vortex layer of anisotropic ferromagnetic bodies in a non-magnetic container located in an apparatus with an external electromagnetic field, characterized in that the binder together with carbon nanotubes and a superplasticizer in the form of a powder is fed through a non-magnetic continuous cavity through the internal cavity pipes into the zone of rotating anisotropic ferromagnetic bodies with a diameter of 1.2 mm and a length of 5-10 mm, having an energy saturation of the working zones not less than 100 kW / m ^3, the movement of which provides a device with an outer electromagnetic field.