RU1790562C - Method of preparing plasticized additive for concrete mixture - Google Patents

Abstract

Usage: production of building materials and for the preparation of additives for concrete mixtures. SUBSTANCE: method for preparing a plasticizing additive consists in mixing lignosulfonates and caustic soda with an angular velocity of at least 50 rad / s to the opacity phase of the solution for the infrared spectrum. The strength of concrete with an additive in an amount of up to 0.23% by weight of cement is up to 36 MPa, while the mobility of the concrete mixture is up to 29.5 cm, and the consumption of the additive is up to 0.25% by weight of cement. 1 tab.

Description

The invention relates to building materials, in particular plasticizing additives for concrete mixtures.

A known method of preparing a plasticizing additive by mixing technical lignosulfonates in hydrodynamic mode with sodium hydroxide in a ratio of 1: (0.7-1.2), respectively.

Closest to the claimed is a method of preparing a complex additive for concrete mix, including lignosulfonate and sodium hydroxide by stirring for 10-20 minutes. and the sediment is within 1-2 hours, The specified method is accepted by the authors as a prototype.

The purpose of the invention is to increase the ductility of the concrete mixture and the strength of concrete, as well as to reduce the consumption of additives.

This is achieved by the fact that in the method for preparing a plasticizing additive, which involves mixing an aqueous solution of technical lignosulfonates with sodium hydroxide, mixing is carried out at an angular velocity of 50-300 rad / s to the opaque phase of the solution for the infrared spectrum.

With vigorous stirring, the solution is saturated with air, the contact surface of the reagents increases, and the reaction of formation of complex polymers is more active. When the solution reaches the opacity phase for the infrared spectrum, the process of interaction of the lignosulfonate and alkali and saturation of the solution with air ends. The resulting mixture is close in physical state to the emulsion, which, during the preparation of the concrete mixture, more actively interacts with the components of the concrete mixture, increases its plasticity and strength of concrete.

The proposed method is implemented as follows.

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Aqueous solutions of LFB and NaOH in the 9: 1 state, calculated on the weight of dry matter, are pumped into the forced-action mixer. Stirring is carried out at normal temperature at an angular speed of 50-300 rad / s until the opacity phase for the infrared spectrum is reached. As a means of monitoring the readiness of the product, an IFC-type flow-through optical density detector is used, the sensor is installed in the mixer. The detector measures N1 (the luminous flux at a wavelength of 900 nm, attenuated by the test compound passing through the optical channel of the sensor. The readiness criterion for the product is the establishment of stable minimum detector readings, which corresponds to the maximum optical density of the mixture.

At stirring speeds of less than 50 rad / s or more than 300 rad / s, the effect of saturating the solution with air does not occur.

5 Concrete mix is prepared from cement М-500, crushed stone of granite FR. 3-5 mm and sand enriched with Mkr 2.87 with a ratio of components C: P: Sh 1: 1.46: 3.14 and W / C

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10 The composition of the additive and physico-mechanical characteristics of the concrete mixture and concrete are presented in the table.

As can be seen from the table, the application of the proposed method will reduce

15 NaOH content and minimize

the presence of free alkali; reduce

additive preparation time, increase

 plasticity of concrete mix and increase

concrete strength.

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Form l a isobret and

A method of preparing a plasticizing additive for a concrete mixture, including mixing an aqueous solution of lignosulfonate and caustic soda, is similar and so that, in order to increase the mobility of the concrete mixture and the strength of concrete, as well as reduce the consumption of the additive, mixing is carried out with angular velocity of 50-300 rad / s to the phase of the opacity of the solution for the infrared spectrum.