RU2246461C1 - Complex additive - Google Patents

Abstract

FIELD: manufacture of building materials.

SUBSTANCE: object of invention is to increase stability of foam and to reduce shrinkage of concrete samples. For that, invention provides complex additive comprising hydrochloric and sulfuric acid salts, low-grade lignosulfonates, and, additionally, ethanolamines, said salts, in particular, being calcium, sodium, and potassium chlorides, sodium, potassium, and iron sulfates, and said ethanolamines being triethanolamine or monoethanolamine. Components are used in following proportions, wt %: chlorides 46-43, sulfates 24-31, lignosulfonates 4-8, and ethanolamines 9-15.

EFFECT: improved performance characteristics of concretes.

4 cl, 2 tbl

Description

The invention relates to additives for concrete and mortar mixtures mainly for foam concrete.

A complex additive is known containing hardening accelerators: hydrochloric acid salts (calcium chloride and sodium), aluminum sulfate, chromate or sodium dichromate (potassium) and a plasticizer - calcium lignosulfate (patent PNR No. 179607, December 18, 79).

The disadvantage of this additive is low efficiency during steaming and insufficient intensity of hardening at 28 days of age,

Closest to the proposed invention in technical essence and the achieved result is a complex additive comprising hydrochloric and sulfuric acids, sodium nitrite and a plasticizer - sulfite-alcohol stillage in the following ratio, wt.%:

Potassium chloride 10-40

Sodium nitrite 10-40

Sulphite-alcohol bard 2-10

Sodium Sulfate 10-78

(A.S. No. 633840, BI No. 43, 11/30/78)

However, concrete with this additive has insufficient strength, as well as significant shrinkage in the hardening process, low foam resistance.

The objective of the present invention is to increase the coefficient of resistance of foam and strength, reducing the shrinkage of concrete samples.

The problem is solved due to the fact that the complex additive additionally, in contrast to the known additive, contains amines, and as a plasticizer, technical lignosulfonates (LST) in the following ratio of components, wt.%:

Salts of hydrochloric acid 46-63

Sulfuric acid salts 24-31

Amines 9-15

Technical lignosulfonates 4-8

As a salt of hydrochloric acid, the additive may contain calcium, sodium and potassium chlorides, as a salt of sulfuric acid - sodium, potassium and iron sulfates, and as amines - triethanolamine, diethanolamine, monoethanolamine.

Chlorides accelerate the process of curing in the early stages, but reduce the stability of the foam, increase shrinkage. Sulfates increase the stability of the foam in the cement system and reduce the shrinkage of the finished product, which makes it possible to manufacture larger products. In the presence of amines, strength increases in the initial stages of hardening and an increase in the strength characteristics of concrete is achieved with a lower content of chlorides and sulfates.

Technical lignosulfonates plasticize the mixture, reduce the amount of mixing water, and indirectly, together with other additives, increase strength indicators and reduce shrinkage.

Concrete example

405 g of Portland cement M500.134 g of quartz sand, 185 ml of water, 800 ml of foam and 3% of a complex additive consisting of 63% hydrochloric acid salts, 24% sulfates, 9% amines and 4% LST were mixed (composition No. 4, table 1 ) The foam was prepared based on sodium secondary alkyl sulfates. Samples — cubes with a rib size of 10 cm — were molded from the mixture. Samples with different ratios of components of the claimed complex additives and with the known additive were made in the same way (table 1).

After hardening, the samples were tested in a press. The test results are presented in table 2.

In addition, the foam resistance in the cement-sand mixture (foam resistance coefficient) and the shrinkage of the finished foam concrete on samples 4 × 4 × 16 cm were determined.

The test results allow us to conclude that the samples with the inventive additive have higher strength characteristics, increased foam resistance coefficient and lower shrinkage compared to the prototype.

The inventive complex additive can be used in the manufacture of products from ordinary heavy concrete, as well as in monolithic construction.

Claims (4)

1. A complex additive, including salts of hydrochloric and sulfuric acids and technical lignosulfonates, characterized in that it contains calcium, sodium, potassium, sodium, potassium, iron and additional ethanolamines as indicated salts in the following ratio, wt.%: specified chlorides 46-63 specified sulfates 24-31 technical lignosulfonates 4-8 ethanolamines 9-15 2. The additive according to claim 1, characterized in that it contains calcium and sodium chlorides as chlorides. 3. The additive according to claim 1, characterized in that it contains sodium and iron sulfates as sulfates. 4. The additive according to claim 1, characterized in that it contains triethanolamine and monoethanolamine as ethanolamines.