SU1188137A1 - Method of preparing cellular concrete mixture - Google Patents

Description

The invention relates to the production of building materials and can be used in the manufacture of products from cellular concrete based on cement, lime, slag-5 and mixed binders.

The purpose of the invention is to reduce the density and thermal conductivity of concrete products.

The invention consists of .10 as follows.

As a result of supplying the initial dose of aluminum powder in an amount of 30-65 wt.% Of its total amount, a more uniform-15 distribution of the blowing agent particles in the volume of the concrete mixture occurs and their dispersion (flocculation destruction), as well as crushing of the resulting initial gas bubbles into more small.

The rest of the gasifier is introduced into the mixer last, after the supply of sand slime, cement, lime-sand 25 binder and mixing the mixture for 0.5-3.5 minutes ^ until it reaches a temperature of 30-55 C. During this period due to hydration astringent temperature

the concrete mix rises to 30-55 ° C, 30 and the lowest temperature value equal to 30 ° C refers to mixtures with the maximum lime content, and the highest, equal to 55 ° C, corresponds to the minimum lime content 35 and the maximum cement content.

At temperatures above 55 ° C, there is an intense gas evolution in the mixer, which leads to useless gas loss. At temperatures below 30 ° C, practically no gas evolution occurs, which does not ensure the formation of small gas bubbles due to the fragmentation of the initial 45 gas bubbles. The second dose is mixed with the components of the mixture for 0.5-1.5 minutes, after which the prepared aerated concrete mixture is discharged into the form. 50

Due to the fact that the second dose of aluminum powder resides in the mixer for an insignificant (0.5-1.5 min) time, intensive gas formation 55 occurs after the mixture is fed into the mold, thus forming large gas bubbles.

The result is a redistribution of previously formed small gas bubbles among large bubbles, therefore, a more dense, approaching hexagonal, packing of all gas bubbles is carried out and the necessary conditions are created for the formation of the most optimal three-modal macroporous structure of cellular concrete.

Example. Cell concrete mixture composition,% by weight of dry components: sand in the sludge 65-75; cement 13-22; lime (CaO content 100%) 11-14; • aluminum powder 0.08-0.085; В / Т 0,38-0,40 is prepared in SMS - 40B vibrobazobetonomixer as follows. In the mixing chamber, SMS 40B is fed in divided doses with a suspension of aluminum powder. The first dose of aluminum powder in the amount of 30 or 65% is fed into the mixing chamber with mixing water. The second dose of aluminum SUSPENDENCE will be delivered to the SMVSITEL ’chamber last. after introducing into the mixing chamber sandy sludge, cement, lime-sand binder and mixing the mixture for 0.5 or 3.5 minutes until it reaches a temperature of 30 or 55 ° C. After that, all components of the aerated concrete mixture are mixed for 0.5.-1.5 min and the mixture is unloaded into forms. After swelling of the aerated concrete mixture, aging and cutting the raw material into products, the latter are steamed. in an autoclave mode, for example, 2.5 + 8 + 3 hours at 0.8 MPa.

The results of the comparative tests of the proposed and known methods are given in the table.

The optimal parameters for preparing a concrete mixture are the supply of aluminum powder to the mixing chamber in separate doses: the first dose is supplied with mixing water in an amount of 30-65 wt.% Of the total amount of aluminum powder, the second dose after the introduction of sand sludge, cement, lime sandy binder and mixing the mixture for 0.5-3.5 minutes until it reaches a temperature of 30-55 C.

The proposed method compared

with known allows to reduce the density of products from 700 to 600 kg / m ³ ,

improve thermal insulation properties

by 25-30%, and also increase the strength3

1188137

four

ny indicators. Due to this, the consumption of raw materials decreases;

fishing and energy costs for heating buildings.

The method of preparation of concrete mixture

First

The second

Aluminum content in a dose, wt.% Of the total amount of aluminum powder

one-- —————— * —— Time Tempera- Indicators concrete Coefficient - move tour laugh cient shiv a- si before Density, Limit heat- to do by serving kg / m ^u durable- about introduce- second ti water of understanding doses, ° C compression, ti track- MPa W / m <k it is up to Threat, min

Famous

Suggested by example

1 20

2 30

3 47

4 65

5 80

100 80 0.3 70 0.5 53 2.0 35 3.5 20 4.0

720 55 '673 thirty 602 42 590 55 615 55 682

3.5 0.177

3.2 0.171

3.5 0.139

4.1 0.135

3.7 0.141

3.2 0.173

Claims (1)

THE METHOD FOR PREPARING A CELL-CONCRETE MIXTURE, which includes the supply of mixing water, sand slime, cement, lime-sand binder and aluminum powder into the mixer, characterized in that, in order to reduce the density and thermal conductivity of aerated concrete, 30-65 aluminum powder is applied to the unit. mixing, and the rest - after filing sandy sludge, cement, lime-sandy binder and mixing the mixture for 0.5-3.5 minutes until it reaches a temperature of 30-55 ° C. 00 00 00 m 1 1188137 2