SU1574580A1 - Method of preparing concrete mixture - Google Patents

Abstract

The invention relates to the building materials industry to the technology of building mixtures. The aim of the invention is to increase the strength and water resistance. The mixture of coarse and fine aggregate is mixed with an aqueous solution of a strong acid with a concentration of 2 ^. 10 ^-2 ... 4 ^. 10 ^-2 for 0.5-1.5 minutes, taken up in an amount equal to the water-holding capacity of the aggregate mixture, after which cement and 80% of the remaining mixing water are added, the mixture is stirred for 1 minute, then the plasticizer is added with the remaining mixing water and the mixture is finally stirred until uniform. 1 tab.

Description

The invention relates to the building materials industry, to the technology for preparing a concrete mix from aggregate, cement and water, followed by molding articles from it.

The aim of the invention is to increase the strength and water resistance.

The method is carried out as follows.

M400 cement and M500 cement are used to prepare the concrete mix. The filler is used; sand of a mechanized quarry with a grain size of 2.48 and a content of powdered clay impurities of 2.2%, as well as crushed stone from a gravel fraction of 5-20 mm with a grade of crushability of Dr8 and a content of needle-like and laminated grains 12 , 7%.

The composition of the concrete mix, kg / m3:

Gravel crushed stone 1190

Sand545

Cement497

Water160

As plasticizers use LST-T (TU 81-04-255-73) and C-3 (TU 6-14-19-205-78). Their content is respectively 0} 15 and 0.6% by weight of cement.

The aggregate mixture is mixed with a solution of sulfuric acid (either hydrochloric or nitric) with a concentration of 10-g; 2-U-12-; W Yu-1; 4CHO gi 5 -10 mol / l. The solution is taken in an amount equal to the water-holding capacity of the aggregate mixture. For this, a filler mixture is preliminarily taken in an amount of 5 kg (1: 2 ratio), 500 ml of water are introduced, mixed, the mixture is placed on a plastic

sp 1

J

SP

00

well, it is tilted at an angle of 30 to allow water to flow off without being held by the surface of the aggregate grains. After 10 minutes, the wet aggregate mixture is boiled out and the water retention capacity (%) is determined using the formula m, -m

Sv

100%,

t

t.

- dry aggregate mass, kg / m3;

- wet filler mass kg / m3.

For the aggregate composition used, selected using the principle of obtaining minimal intergranular hollowness, a 4% acid solution based on the weight of the aggregate mixture is introduced. Then cement and 80% of the remaining gate water are supplied to the mixer. After stirring for 1 min, a solution with a plasticizer is introduced, equal in volume to 20% of the remaining mixing water. The mixture is finally stirred for another 30 s, and then the concrete mixture is tested according to GOST 10181.0-81 - GOST 10181.4-81,

five

0

five

determine the compressive strength (GOST 10180-78), waterproof (GOST 12730.5-84).

The test results are presented in the table (see page 3-5).

Claims (1)

Invention Formula I A method of preparing a concrete mix, which includes treating the aggregate with an aqueous solution of a strong acid, followed by mixing with cement and water, characterized in that, in order to increase the strength and impermeability, coarse and fine aggregates are simultaneously treated with an aqueous solution of a strong acid with a concentration of 2-10-2- 4 mol / l in an amount equal to the water-holding capacity of the aggregate for 0.5-1.5 minutes, then cement is added and 80% of the remaining mixing water is mixed, after which1 the plasticizer is introduced with the rest of the water mixing and final mixing is carried out. Note. The numerator contains the data when used as a plasticizer LST - T, in the denominator C-3.