RU2345968C2 - Composition for making construction material - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: present invention can be used in construction materials when making block and monolithic concrete. The composition contains cement, sand, water and carbon-bearing nano-material - soot, obtained using an electroarc method, and containing 7% of carbon nanotubes, with the following ratios of components, in wt %: cement 20-30, sand 50-70, carbon-bearing nano-material 1-2, water constitutes the rest.

EFFECT: increased compression strength of the construction material.

1 ex, 2 dwg

Description

The invention relates to compositions based on mineral binders and may find application in the building materials industry in the manufacture of block and monolithic concrete.

A known composition for producing building material, including cement binder, water and 0.01-2.5 wt.% Metal-containing carbon nanostructures in a mixture of polyvinyl alcohol with copper chloride (RF Patent, No. 2281262, class C04B 28/00, 2006).

The disadvantage of this composition is a slight increase in strength by 1.7 times with the addition of metal-containing carbon nanostructures (multilayer nanotubes).

The closest analogue is the method (Patent of the Russian Federation, No. 2233254, CL04B 28/02, 2004), in which carbon clusters of the fulleroid type with the number of carbon atoms 36 or more are used with the following ratio of components in the composition (wt.%): Mineral binder (cement) 33-77; carbon clusters of the fulleroid type 0.0001-2; water is the rest. As carbon clusters of the fulleroid type, the composition may contain polydispersed carbon nanotubes. As carbon fulleroid type clusters, it can contain polyhedral multilayer carbon nanostructures with an interlayer distance of 0.34-0.36 nm and a particle size of 60-200 nm. As carbon clusters of the fulleroid type, the composition may contain a mixture of polydispersed carbon nanotubes and C60 fullerene. The disadvantage of this composition is a slight increase (1.3 times) in the compressive strength of concrete.

The task is to obtain a high-strength composition of building materials.

The technical result consists in increasing the compressive strength of the building material.

The technical result is achieved in that the composition for producing a building material containing cement, sand, water and a carbon nanomaterial containing carbon nanotubes according to the invention contains carbon black obtained by the electric arc method and containing 7% carbon nanotubes as the specified carbon nanomaterial, in the following ratio of components , wt.%:

Cement 20-30 Sand 50-70 Specified carbon nanomaterial 1-2 Water rest

Soot containing 7% carbon nanotubes was obtained from MPG-4 grade graphite at the facility in bulk quantities (about 1 kg / h) with the following main parameters: current strength 1150 A, voltage 42 V, anode diameter 30 mm by the electric arc method described in article Grushko Yu.S., Egorov V.M., Zimkin I.N., Orlova T.S., Smirnov B.I. Some physicomechanical properties of cathode deposits formed upon receipt of fullerenes by the arc method (Journal of Solid State Physics. - 1995. - T.37. - N6. - c. 1838-1842).

Figure 1 shows the dependence of the compressive strength P of the compositions for obtaining a building material on the solidification time t.

Figure 2 - morphology of unmodified (a) and modified (b) carbon nanomaterial (1% by weight) of the composition to obtain a building material.

Example

Sand in an amount of 60 wt.% Moisten with a small amount of water. Carbon nanomaterial - carbon black containing 7% nanotubes - is added to it. The resulting composition was mixed until a homogeneous mass was obtained, since it was necessary to achieve a uniform distribution of nanotubes in the sand. Then add Portland cement grade PC 400 D0 in an amount of 25 wt.% And water in an amount of 14.62, 14.5, 14, 13 and 15 wt.%. The compositions were prepared with the content of carbon nanomaterial in the amount of: 0.38%, 0.5%, 1%, 2% and in the absence of carbon nanomaterial (control sample), respectively.

Tests for compressive strength were carried out according to standard methods. For the strength test, 2 x 2 x 2 cm cubes were placed between the press plates so that their faces, horizontal during manufacture, were in a vertical position and the surface with the marking was facing the tester. The compressive strength was measured after 1, 3, and 28 days. The compressive strength of the modified carbon nanomaterial composition of the building material exceeds the strength of the unmodified composition to obtain the building material more than 2 times at a percentage of 1-2% (figure 1). When the percentage of carbon nanomaterial is less than 1% or more than 2% by weight, the compressive strength of the composition to obtain a building material decreases. Nanotubes are a hydrophilic material and intensively absorb water, therefore, a nanomodified carbon nanomaterial composition for producing a building material has a less porous and denser structure. Carbon nanomaterial is an environmentally friendly material.

Claims (1)

Composition for producing building materials containing cement, sand, water and carbon nanomaterial containing carbon nanotubes, characterized in that as the specified carbon nanomaterial contains carbon black obtained by the electric arc method and containing 7% carbon nanotubes in the following ratio, wt.%:
cement 20-30 sand 50-70 specified carbon nanomaterial 1-2 water rest

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