SU1669904A1 - Method for preparing concrete mix - Google Patents

Abstract

The invention relates to the building materials industry and can be used in the preparation of concrete mixtures. The aim of the invention is to increase the strength of concrete and preserve the mobility of the concrete mixture when using substandard aggregates. The surface treatment of aggregates with a 3–7% solution of hydroxyethylcellulose modified with 0.5–1.5% alkali makes it possible to increase the strength of concrete by 30–40% and preserve the mobility of the concrete mix for a long time. Cement saving by improving the contact zone "substandard aggregate - staying" is 20-25%. 1 tab.

Description

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The invention relates to the industrial strength of building materials and can be used in the preparation of concrete mixtures.

The purpose of the invention is to increase the strength of concrete and preserve the mobility of the concrete mix when using substandard aggregates.

The method is carried out as follows.

A concrete mix is used, cement is used, coarse aggregate — granite crushed stone of 10–20 mm fractions with 5% pyleva-clay particles, fine “aggregate” —quartz sand with a grain size of 1.6, containing 6.3% pylevato- clay particles

The composition of the concrete mix is as follows, kg / m3: crushed stone 1250; sand 620; cement 370; В / Ц 0,44 „

The withdrawn fine and coarse aggregate is loaded into a forced-action concrete mixer SP-148 and mixed for 20-30 seconds, dissolving hydroxyethyl cellulose in 0.5-1.5% sodium solution is obtained to obtain a 3-7% solution. The prepared solution, taken in an amount necessary for wetting the entire surface of the fillers within the range of 14-18%, is introduced into the mixture and stirred for 20-40 sec. Then the aggregates are mixed with the cement until it is completely and evenly distributed for 30-40 sec. After that, the remainder of the mixing water is poured in an amount of 86-82%, the mixture is stirred for 20-30 s until a homogeneous mass is obtained.

The following materials are used for the processing of aggregates: oxyetto

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71.6 99.7 2.5 (GOST

cellulose, which is characterized by the following properties:

Viscosity 1%

solution, cp

Solubility,%

Ash content,%

and caustic soda brand chsd0a 4328-77) o

Example 1 - 3, The withdrawn amount of fine and coarse aggregates is mixed in a concrete mixer for 20, 25 and 30 seconds dry. Aggregates are treated with 14% water of a batch containing 0, NaOH solution, with a concentration of hydroxyethyl cellulose of 3% and 40, 35 and 20 are mixed agrees with the required amount of cement and the mixture is mixed, respectively, 20, 30 and 40 s. Shutter the mixture with 86% water and mix for 20 s.

Example 4 - 6. Mixing time and order of introduction of concrete mixture components, as in measures, but aggregates are treated with 16% water containing NaOH solution with an oxy ethylcellulose concentration of 5%. Residual mixing water is 84% o Additional mixing 25 с0

Example The procedure was carried out similarly to examples 1H, but the treatment of aggregates is produced by 18% of water containing 1, NaOH solution, with a concentration of hydroxyethylcellulose 7 and the remainder of the mixing water is 82%. Additional mixing is 30 sec.

After each experiment, the determination of the mobility of the concrete mixture according to Abrams is determined through 0.60 min. From the obtained concrete mixtures, cube samples with measures of 10x10x10 cm are molded, which harden for 28 days under normal moisture conditions and heat and humidity is processed according to 3 + 3 + mode. 6 + 4 at Tizot 80 ° С. The results of determining the mobile concrete and concrete strength characteristics are given in the table.

Claims (1)

40 claims five 0 A method of preparing a concrete mix, which includes mixing aggregates that have been pretreated with an aqueous solution of a surfactant substance with a binder and water for creation, is characterized in that, in order to increase the strength of the concrete and the mobility of the concrete mix when using sub-standard aggregates, the latter is treated with 3 7% solution of ethyl cellulose modified with 0, alkali solution,