RU2432336C1 - Complex additive for concrete mixture - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a complex additive for concrete mixture and can be used in construction when producing concrete and reinforced concrete articles and structures. The complex additive for concrete mixture contains a hyperplasticiser - Odolit-K, and a curing agent - sodium sulphate, with the following ratio of components in wt %: hyperplasticiser Odolit-K 30-38, sodium sulphate curing agent - 62-70.

EFFECT: high rate of increase in strength during early hardening stages with retention of high ultimate strength, high frost resistance and watertightness.

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Description

The invention relates to the field of construction, and in particular to compositions of concrete mixtures and additives for them, and can find application in the production of concrete and reinforced concrete products and structures.

Known complex additive (RU 2100305 C1, 12/27/1997), which is used in the manufacture of reinforced concrete products and structures.

This complex additive includes, in wt.%: The sodium salt of the sulfonated product of the condensation of waste products of phenol with formaldehyde 17.0-79.7; sodium sulfate 10.0-30.0; lignosulfonates 10.0-30.0; polyester or polyorganosiloxane 0.3-3.0. The technical result is an increase in strength while maintaining frost resistance and mobility of concrete, however, the strength properties do not meet the increased requirements for them.

Another complex additive for concrete mix is known (RU 2119900, C1, 10.10.1998), including sodium nitrate, sodium carbonate, sodium sulfate, calcium chloride, calcium carbide, calcium hydroxide.

However, this additive does not sufficiently provide high strength properties of concrete products and frost resistance of concrete.

The closest of the prototypes is a comprehensive additive for concrete mix, including, wt.%: Superplasticizer S-3 - 14-28; sodium sulfate - 14-28; technical lignosulfonate - 3-7; aluminum sulfate - 14-28; Potash - 30-50 (RU 2273613 C2, 04/10/2006).

The disadvantage of concrete with this complex additive is the insufficient rate of curing, low frost resistance and water resistance.

The objective of the present invention is to increase the growth rate of concrete strength in the early stages of hardening while maintaining their high final strength, increasing frost resistance and water resistance.

The result is achieved in that the complex additive for concrete mixture containing a plasticizer and a hardening accelerator according to the invention contains “Odolit-K” hyperplasticizer as a plasticizer, and sodium sulfate as a hardening accelerator in the following ratio of components, wt.%:

Hyperplasticizer "Odolit-K" - 30-38;

The hardening accelerator sodium sulfate - 62-70.

Odolit-K hyperplasticizer based on polycarboxylate ester according to TU 5745-01-96326574-08, hardening accelerator sodium sulfate meets the requirements of GOST 6318-68.

The invention is illustrated by the following example.

To prepare the concrete mix of the production composition, M500 D0 cement of the Volsky plant was used, enriched sand of the Kama field with a particle size module of 2.7, crushed stone from gravel of the Kama field of a fraction of 5-20 mm, in the following ratio (parts by weight):

Cement: crushed stone: sand = 1: 1.74: 1.06

The complex additive was introduced into the concrete mixture in the form of an aqueous solution of working concentration with mixing water in the amount of 2.5-3.2% of the mass of cement in terms of dry matter.

Water was added to the concrete mixture until equal mobility (class P1) was achieved according to GOST 7473-94. The water-cement ratio of the composition without the additive was 0.31, with the complex additive - 0.21, with the addition of the prototype - 0.24.

Samples — cubes with dimensions of 10 × 10 × 10 cm — were made from concrete mixtures. After 1, 3, 7, 28 days of normal hardening, the samples were subjected to mechanical tests. The compressive strength of the samples was determined in accordance with GOST 18105-86.

Such indicators as frost resistance, water resistance, were determined at the age of 28 days of normal hardening according to relevant standards: water resistance according to GOST 12730.5-84, frost resistance according to GOST 10060.0-95.

The compositions of the complex additives and the results of mechanical testing of concrete are given in table. Tests were also conducted concrete mixture and concrete with the addition of the prototype and without additives.

Based on the data obtained, it can be concluded that concrete using a complex additive in a day of normal hardening has a compressive strength higher by 19-27%, after 3 days - 19-28%, after 7 days - 18-26%, through 28 days - 19-27% compared with the prototype.

At the age of 28 days, frost resistance increases by 80-415 cycles, and water resistance - by 1-2 steps compared to the prototype.

The results obtained suggest that the complex additive increases the rate of curing of concrete in the early stages of hardening and allows to achieve high final strength, frost resistance and water resistance.

Claims (1)

Complex additive for concrete mixture containing a plasticizer and hardening accelerator, characterized in that it contains Odolit-K hyperplasticizer as a plasticizer, and sodium sulfate as a hardening accelerator in the following ratio, wt.%:
Hyperplasticizer "Odolit-K" 30-38 Hardening accelerator - sodium sulfate 62-70