RU2055061C1 - Method for preparing cellular-concrete mix - Google Patents

Abstract

FIELD: construction materials. SUBSTANCE: cellular-concrete mix is prepared by mixing a binder, mineral filler and mixing water followed by adding aluminium powder suspension with ethers of ethanolamines and synthetic fatty acids which are taken at the rate of 0.1-10 g per 1 l of mixing water. The general formula of ether is H_(3-n)N-(CH₂CH₂OCOR)_n, where R - alkyl (C₁₀-C₁₆), n = 1-3. EFFECT: preparation of concrete with fine-porous stable structure. 2 tbl

Description

 The invention relates to building materials, in particular to a technology for the preparation of aerated concrete mix.

A known method of preparing a cellular concrete mixture, comprising mixing a binder, which is used slag Portland cement, a mineral component, such as blast furnace slag, with part of the water. An aqueous suspension of lignosulfonates and aluminum powder is introduced into the resulting mixture [1]
The disadvantages of this method are low strength and high bulk density of the resulting concrete.

Closest to the invention in technical essence and the achieved result is a method of preparing a cellular concrete mixture, comprising mixing a binder, mineral filler and mixing water and the subsequent introduction of a suspension of aluminum powder with an organic additive based on synthetic fatty acids [2]
In the manufacture of cellular concrete by this method, it is not possible to achieve a finely porous structure with pore sizes of equal diameter uniformly distributed throughout the volume.

 The proposed method allows to eliminate the above disadvantages and improve the quality of aerated concrete, while reducing the consumption of aluminum powder.

The essence of the invention lies in the fact that as an organic additive use esters of ethanolamines and synthetic fatty acids of the General formula
H _(3-n N (CH ₂ CH ₂ OCOR) _n , where R is alkyl (C ₁₀ -C ₁₆ ), n = 1-3 in an amount of 0.1-1.0 g per 1 liter of mixing water.

 The combination of the principle of high plasticization of the mixture with active air intake allows to obtain high-quality cellular concrete.

 Using the proposed method allows to reduce the consumption of a blowing agent by 20-30% to improve the quality of cellular concrete products by slowing down the initial gas evolution and active air intake.

 The use of known organic additives capable of air entrainment and a blowing agent does not allow to avoid deformation and fusion of pores during their unimodal distribution, as well as to eliminate the mass sediment due to its insufficient stability.

 Using the proposed method, it is possible to obtain a combined method for constructing porosity of aerated concrete. Part of it is formed during mixing of the mixture due to air entrainment, and the other due to gas formation. Moreover, the proposed organic additive manifests itself as a structuring surfactant, capable of forming many small bubbles that stabilize the mass. The mixture due to the introduced organic additives is plastic and lends itself well to mixing.

 PRI me R. For the manufacture of cellular concrete samples using the developed method, a concrete mixture of the compositions indicated in Table 1 is prepared (compositions 2-4). The astringent, mineral component and part of the water are mixed in a laboratory concrete mixer and an aqueous suspension of ether and aluminum powder is introduced into the mixture.

 The amount of ether is taken from the calculation of 0.1-1.0 g / l of total water in the concrete mixture. Mixing the concrete mixture is carried out for 10 minutes The finished mixture is placed in a metal mold 10x10x10, heat treatment is carried out in accordance with the standards.

 In parallel, samples of a similar composition are made, but without the introduction of an organic additive (composition 1) and a composition with the introduction of lignosulfonates (SDB) (composition 5). The cooking modes are the same as in the proposed method. The results are presented in table.2.

 As can be seen from the dynamics of gas evolution, this time is enough to fill the form with a mixture.

 The main gas evolution develops in a mixture already laid in the mold.

 With intensive mixing of the mixture in a concrete mixer, the proposed organic additive promotes air entrainment and, when combined with aluminum powder, contributed to the formation of a porous stable structure with small air pores.

Claims (1)

METHOD FOR PREPARING A CELLULAR CONCRETE MIXTURE, including mixing a binder, mineral filler and mixing water and subsequent administration of a suspension of aluminum powder with an organic additive based on synthetic fatty acids, characterized in that esters of ethanolamines and synthetic fatty acids of the general formula are used as an organic additive
H _{3 - n} N (CH ₂ CH ₂ OCOR) _n ,
where R is C _{1 0} - C _{1 6} -alkyl;
n = 1 - 3,
in an amount of 0.1 - 10 g per 1 liter of mixing water.

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