RU2170718C1 - Foaming agent for making concrete mixes more porous - Google Patents

Abstract

FIELD: manufacture of building materials, more particularly manufacture of light-weight concrete for heat insulation of guard structures and products. SUBSTANCE: foaming agent comprises, %: surfactants, 1-5; saponified wood resin, 1-10; saponified wood resin to surfactant ratio, being from 1 to 2. EFFECT: greater ratio of foam and higher coefficient of using foam. 1 tbl

Description

 The invention relates to the field of production of building materials and can be used in the manufacture of lightweight concrete and products from it.

 Known foaming agent based on anionic surfactants, which contains alkyl sulfates, non-sulfated alcohols and sodium sulfate in the following ratio of components, in% by weight: alkyl sulfates 12-20%, non-sulfated alcohols 4-8%, sodium sulfate 20-40%, water - the rest [ 1]. The disadvantage of this foaming agent is the low resistance of the foam.

A foaming agent is also known which contains, as an anionic surfactant, a triethanolamine salt of lauryl sulfate and additionally a mesher adhesive in the following ratio of components, in% by weight: triethanolamine salt of lauryl sulfate 0.08-0.32%, mesher adhesive 0.2-1, 0%, water - the rest [2]. The preparation of this foaming agent is carried out in the following way: the triethanolamine salt of lauryl sulfate is diluted in water with a temperature of 30-40 ^o C, separately prepare a solution of glue in water with a temperature of 50-60 ^o C, then mix both solutions and carry out foaming.

 The disadvantage of this foaming agent is the low quality of foam concrete, especially low strength due to the separation of the foam concrete in height before hardening, and the low utilization rate of the foam, as well as the complexity of its preparation.

 Closest to the proposed technical solution is a method of manufacturing lightweight polystyrene concrete products, according to which to increase the frost resistance of products and reduce harmful emissions from polystyrene granules, the latter are treated with a complex additive from surfactants (a mixture of dicarboxylic acids 35-60% by weight, salts of organic acids 25-30 % by weight, in the amount of 65-85% by weight) and saponified wood tar (SDO) 15-35% by weight of dry matter. Moreover, the ratio by weight of SDO / surfactant is from 0.17 to 0.58. After processing the granules with the above additive, while mixing a concrete mixture consisting of cement, polystyrene foam aggregate and water, small air bubbles are involved in the cement mortar. / 3 /.

 The disadvantage of complex chemical additives is that it does not provide a significant reduction in the density of concrete due to the low coefficient of foam utilization.

 The technical result of the invention is to increase the utilization rate of technical foam.

This result is achieved by the fact that, in comparison with the prototype, a foaming agent is used to prepare the foam with the following content of components, wt.%:
SAW - 1-5
SDO - 1-10
Water - 85-98
in this case, the SDO / surfactant ratio should be from 1 to 2. This content and the ratio of components is a distinctive feature of the present invention and ensures the production of such a foaming agent light and resistant foam, which is then mixed with cement and, if necessary, with aggregate (ash, ground slag or sand, etc.) and ultimately allows you to get concrete with a density of, for example, 350 kg / m ³ without the introduction of polystyrene granules and, accordingly, without additional environmental problems and fire safety nos of manufactured products.

 Foam obtained only using a complex additive of the prototype when introduced into the foam concrete mass is relatively quickly destroyed as a result of exposure to salts and electrolytes formed during the interaction of cement with water.

 This leads to a decrease in the coefficient of foam utilization and to the production of multi-density foam concrete products. To slow down the destruction of the foam, it is proposed to use a mixture with a high ratio of SDO / surfactant. Surfactants and LMS contained in the "walls" of the foam at the proposed ratio, form in the foam concrete mass on the surface of particles of cement, sand or other filler and air bubbles long-fiber adsorption-hydrated layers with high density. These layers serve as a structural and mechanical barrier to the destruction of the foam walls at the point of contact with solid particles and prevent the separation of the foam concrete mass, that is, contribute to its stability and, accordingly, lead to an increase in the foam utilization rate and to obtain equal-density foam concrete products, especially with a height of more than 0.3 -0.5 m.

 The preparation of the proposed foaming agent is as follows.

 The surfactant (1-5%) was diluted in water (85 - 98%), then saponified wood resin (1-10%) was introduced and mixed thoroughly. Moreover, the ratio of SDO / surfactant was changed from 1 to 2. Obtaining foam was carried out by mechanical and aeration method.

 The specific compositions of the foaming agent and the characteristics of the foam are shown in the table.

 Examples 1 to 4 - the proposed compositions and their parameters.

 Examples 5 to 8 are formulations with exorbitant values.

 Examples 9-10 of the prototype.

As a surfactant used:
- in example 1, 6 - secondary alkyl sulfates (VA)
- in example 2, 6 - triethanolamine (TEA)
- in example 3, 7 - monoalkyl esters of sulfuric acid (MAESK)
- in example 4, 5 - higher fatty alcohols (VZhS).

 The table shows that the proposed foaming agent allows to obtain foam with a high ratio and a higher coefficient of foam utilization. The introduction of LMS in an amount of less than 1% leads to a sharp decrease in the coefficient of use of the foam, and more than 10% leads to a sharp decrease in the multiplicity of the foam. An increase in the amount of surfactants of more than 5% is not economically feasible, since it does not give a technical effect, and a decrease of less than 1% leads to a sharp decrease in the foam ratio. Moreover, not only the content of LMS and surfactant is important, but also their ratio, which should not be less than 1 or more 2. When the ratio is less than 1 (examples 9, 10), even with a high content of surfactants (2-5%), it does not work resistant foam, and with a ratio of more than 2 (example 7, 8), the multiplicity of the foam decreases sharply.

The technical effect of the use of the proposed foaming agent when comparing the uniformity of the manufactured foam concrete products is especially obvious. The difference in the density of the lower and upper layers of samples of foam concrete 600 mm high with a density of 350 kg / m ³ made using a foaming agent according to the prototype is several times higher than those obtained using the proposed composition of the foaming agent.

The proposed foaming agent is industrially applicable and can be used in the production of foam concrete,
Sources of information taken into account when preparing the application:
1. Auth. testimonial. N 302320, "Foaming agent", cl. S 04 V 21/00, BI N 15, 1971.

 2. Auth. testimonial. N 1184835, "Foaming agent for porous concrete mixtures", cl. S 04 B 28/20, BI N 38, 1985.

 3. RF patent N 2082695, "A method of manufacturing environmentally friendly, lightweight polystyrene concrete products", cl. From 04 to 38/00, 40/02.

Claims (1)

Foaming agent for porous concrete mixtures, including surfactant, saponified wood resin (SDO) and water, characterized in that it contains these components in the following ratio, wt.%:
SAW - 1 - 5
SDO - 1 - 10
Water - 85 - 98
while the ratio of LMS / surfactant by weight should be from 1 to 2.

Images