RU2482083C2 - Complex additive for concrete mixtures and mortar - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to composition of a complex additive for concrete mixtures and mortar and can be widely used in production of monolithic and prefabricated structures, primarily for hydraulic engineering structures and road concrete. The complex additive contains the following, (pts.wt): superplasticiser S-3 10-30, polyethylene glycol and/or propylene glycol with molecular weight of 250-3500 5-55, carbamide 10-60. In a special case, the complex additive further contains sodium formate, with the following ratio of components (pts.wt): superplasticiser S-3 10-30, polyethylene glycol and/or propylene glycol 5-55, carbamide 10-60, sodium formate 5-35.

EFFECT: high frost resistance of concrete in salts and high strength of concrete aged 28 days while maintaining and slightly improving properties, particularly cone slump.

5 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.

The use of urea (urea) as a modifier that accelerates the setting of concrete mixtures and hardening of concrete is known (GOST 2081-75, also V.G. Batrakov "Modified Concretes", M., 1998, p. 746).

It is known to use polyethylene oxide (polyoxyethylene, polyethylene glycol) as a modifier, stabilizing, water-retaining effect and improving the pumpability of concrete mixtures (GOST 2081-75, also V. G. Batrakov “Modified Concretes”, M., 1998, p. 745).

It is known the use of polyethylene oxide in the composition of complex additives for concrete (ed. St. USSR No. 14447779, publ. In 1988; 1143719, publ. In 1985), reinforcing the plasticity of the concrete mortar, its strength and frost resistance. It is known to use polyethylene oxide with a molecular weight of (4.1-6.0) 10 ⁶ as an organic additive for a heat and sound insulating mortar to improve stackability and volume uniformity.

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

Known complex additive for concrete mix and mortar containing a mixture of sodium salts of polymethylene naphthalene sulfonic acids sold under the trade name superplasticizer C-3, and a mixture of ballast salts of coke oven gas desulfurization based on thiosulfate and sodium thiocyanate according to RF patent No. 2228306 (publ. 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 a complex additive C-3 superplasticizer, a mixture of polyethylene glycol and / or polypropylene glycol with a molecular weight of 250-3500 and urea in the following ratio of components (parts by weight):

Superplasticizer C-3 - 10-30;

Polyethylene glycol and / or propylene glycol - 5-55;

Urea - 10-60.

In the particular case of the invention, the inventive complex additive further comprises sodium formate in the following ratio of components:

Superplasticizer C-3 - 10-30;

Polyethylene glycol and / or propylene glycol - 5-55;

Urea - 10-60;

Sodium formate 5-35.

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;

Low molecular weight polyethylene glycol TU 2483-71150986-2006;

Polypropylene glycol TU 6-09-2434-81;

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

Sodium formate TU 2432-011-00203803-98.

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 ЦЕМI42,5 Б made by OJSC "Mordovcement";

- 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-3-10, polyethylene glycol 55, urea 10.

Example 2. Prepared a complex additive by mixing (mass parts): superplasticizer C-3 - 20, polypropylene glycol - 30, urea - 35.

Example 3. Prepared a complex additive by mixing (mass parts): superplasticizer C-3 - 30, polyethylene glycol - 5, urea 60.

Example 4. Prepared a complex additive by mixing (mass parts): superplasticizer C-3 - 20, a mixture of polyethylene glycol and polypropylene glycol (50:50) - 30, urea - 35, sodium formate - 20.

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 150 21 2435 44,2 2 200 22 2475 46.2 3 150 23 2445 44.7 four 175 22 2460 45.9 5 (prototype) one hundred 21 2395 37.7

Information sources

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

2. RF patent for the invention No. 2130442 (published in 1999).

3. USSR author's certificate No. 1447779 (published in 1988).

4. Copyright certificate of the USSR No. 1143719 (published in 1985).

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

6. Patent of Ukraine for invention No. 24298 (published in 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 polyethylene glycol and / or polypropylene glycol with a molecular weight of 250-3500 and urea in the following ratio, wt.h .:
Superplasticizer S-3 10-30 Polyethylene glycol and / or propylene glycol 5-55 Urea 10-60 2. The complex additive according to claim 1, characterized in that it further comprises sodium formate in the following ratio of components, parts by weight:
Superplasticizer S-3 10-30 Polyethylene glycol and / or propylene glycol 5-55 Urea 10-60 Sodium formate 5-35