RU2479522C2 - Complex additive for concrete mixtures and mortar - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a composition of a complex additive for concrete mixtures and mortar and can be widely used in production of monolithic and prefabricated structures, mainly for hydraulic engineering structures and road concrete. The complex additive contains the following (pts.wt): superplasticiser S-3 5-50, isopropyl alcohol 10-55, carbamide 5-45. In a special embodiment of the invention, the complex additive contains the following (pts.wt): superplasticiser S-3 10-30, isopropyl alcohol 10-55, carbamide 5-45, ballast salts from desulphurisation of coke gas based on sodium rhodanate and thiosulphate 5-50.

EFFECT: high frost resistance of concrete in layers and high strength of the concrete after 28 days.

2 cl, 4 ex, 1 tbl

Description

The invention relates to compositions of chemical additives for concrete mixtures and can be widely used in the manufacture of monolithic and prefabricated structures, mainly for hydraulic structures and road concrete.

Concrete used in hydraulic engineering and road construction has high demands on durability, which, first of all, is evaluated for frost resistance and water tightness of concrete. The modern variety and complexity of technical problems form new challenges for improving building materials used in various fields. One of the solutions to such problems is the creation and use of new complex additives for concrete mixtures and mortars, rationally combining the necessary technological and operational characteristics.

It is known the use of urea (urea) as a modifier that accelerates the setting of concrete mixtures and hardening of concrete (GOST 2081-75, also VG Batrakov. Modified concrete. M: 1998, p.746).

The use of isopropyl alcohol in the composition of additives for concrete mixtures according to the patent of the Russian Federation for the invention No. 2066306 (published in 1996) to increase the strength of concrete is known

A common disadvantage of these compositions are low strength indicators when applied in concrete compositions, as well as low frost resistance.

A well-known complex additive for concrete mix and mortar containing a mixture of sodium salts of polymethylene naphthalene sulfonic acids sold under the trade name C-3 superplasticizer and a mixture of ballast salts of coke oven gas purification based on thiosulfate and sodium thiocyanate (hereinafter referred to as SBS) according to RF patent No. 2228306 (opub) . in 2004). Significant disadvantages of this complex additive are insufficient strength in the early stages of hardening and low frost resistance in salts.

The closest solution to the claimed is the use as an additive superplasticizer C-3 (Ukrainian patent No. 24298, publ. In 1998). Superplasticizer C-3 is added to the concrete mixture in an amount of 1.35-1.65 by weight of cement. The known additive causes an increase in the plastic properties of the concrete mixture at a reduced water content, which prevents its delamination during transportation, and also contributes to the production of high-density concrete. Significant disadvantages of the solution according to the prototype are insufficient strength in the early stages of hardening and low frost resistance in salts.

The essence of the invention is as follows.

The technical problem to which the claimed invention is directed is to develop a complex additive composition for concrete mixtures and mortars for primary use in hydraulic and road construction.

The technical result of the claimed invention is to increase the frost resistance of concrete in salts and to increase the strength of concrete at the age of 28 days while maintaining and partial improvement of technological parameters, in particular, cone precipitation.

The specified technical result is achieved due to the use of S-3 superplasticizer, isopropyl alcohol and urea as a part of the complex additive in the following ratio of components (parts by weight):

Superplasticizer C-3 - 5-50;

Isopropyl alcohol - 10-55;

Urea - 5-45.

In the particular case of the invention, the inventive complex additive further comprises SBS in the following ratio of components (parts by weight):

Superplasticizer C-3 - 5-50;

Isopropyl alcohol - 10-55;

Urea - 5-45;

SBS - 5-50.

The achievement of the technical result is due to the synergistic effect of the ingredients used.

For the implementation of the invention can be used the following substances:

Superplasticizer S-3 TU 5745-001-97474489-2007;

Isopropyl alcohol GOST 9805-84 "Isopropyl alcohol. Technical conditions ";

Urea GOST 2081-92 "Urea. Technical conditions ";

Salt ballast desulfurization of coke oven gas.

The advantages of the claimed invention were evaluated by comparing with the prototype the following indicators: frost resistance in salts (according to the second and third basic methods for determining frost resistance according to GOST 10060-2-95), cone precipitation, concrete density, concrete strength at 28 days.

To study the properties of the claimed additives, a concrete mixture was prepared containing cement 1 part, sand 1.8 parts, crushed stone fractions 5-20 mm 2.8 parts, water 0.4 parts. To prepare the concrete mixture used:

- cement CEM I 42.5 B manufactured by Mordovcement OJSC;

- sand for construction works of the 1st class (medium, MKR = 2.1), the Khromtsovsky quarry of Furmanov city;

- crushed granite, fractions 5-20 mm, M 1200, frost resistance grade F 300, Pitkyaranta.

The claimed additive was introduced into the concrete mixture with mixing water in an amount of 0.7-2% of the liquid product by weight of cement. Tests of the inventive integrated additives in the composition of concrete mixtures was carried out according to GOST 10181-200 "Concrete mixtures. Test methods ", GOST 10180 - GOST 10060.2-95" Concretes. An accelerated method for determining frost resistance during repeated freezing and thawing. ”

A specific implementation of the invention can be illustrated by the following examples.

Example 1. Prepared a complex additive by mixing (parts by weight): Superplasticizer C-3 - 5, isopropyl alcohol - 55, urea - 5.

Example 2. Prepared a complex additive by mixing (parts by weight): Superplasticizer C-3 - 25, isopropyl alcohol - 32, urea - 35.

Example 3. Prepared a complex additive by mixing (mass parts) Superplasticizer S-3 - 50, isopropyl alcohol - 10, urea - 60.

Example 4. Prepared a complex additive by mixing (parts by weight) Superplasticizer C-3 - 25, - isopropyl alcohol - 32, urea - 25, SBS - 25.

Example 5 (in accordance with the prototype). S-3 superplasticizer was introduced into a standard concrete mixture in an amount of 0.25 parts by weight.

The table shows the comparative test results of the inventive complex additives and additives in accordance with the solution of the prototype.

Example Frost resistance, cycles (in salts) Cone draft, cm Density of concrete at the age of 28 days Strength at the age of 28 days, MPa one 125 21 2425 41.2 2 200 22 2485 47.2 3 150 23 2455 45.1 four 150 22 2460 49.5 5 (prototype) one hundred 21 2395 37.7

Bibliographic data

1. V.G. Batrakov. Modified Concrete. M .: 1998, p. 745.

2. RF patent for the invention No. 2066306 (publ. 1996).

3. RF patent for the invention No. 2228306 (publ. 2004).

4. Patent of Ukraine for invention No. 24298 (publ. 1996).

Claims (2)

1. A complex additive in concrete mixtures and mortars containing superplasticizer C-3, characterized in that it further comprises a mixture of isopropyl alcohol and urea in the following ratio, wt.h .:
Superplasticizer S-3 5-50 Isopropyl alcohol 10-55 Urea 5-45 2. The complex additive according to claim 1, characterized in that it further comprises sodium formate in the following ratio of components:
Superplasticizer S-3 10-30 Isopropyl alcohol 10-55 Urea 5-45 Salt ballast desulfurization coke oven gas based thiosulfate and sodium thiocyanate 5-50