RU2433099C1 - High-strength concrete - Google Patents

Abstract

FIELD: chemistry. ^ SUBSTANCE: invention relates to high-strength concrete and can be used in making articles in civil and industrial construction, monolithic construction, concreting densely reinforced structures, as well as for erection of special-purpose structures. The high-strength concrete prepared from the crude mixture containing a complex additive which is a sol of iron (III) hydroxide with density 1.021 g/cm3, pH 4.5-5.5 and super-plasticiser Muraplast FK 63, with the following ratio of components in wt %: 85.50-86.00 and 14.00-14.50 respectively, with the following ratio of components of the crude mixture in wt %: portland cement 20.60-27.40; sand 21.80-24.70; crushed rock 42.40-44.50, said additive 0.70-0.90; water 7.70-9.30. ^ EFFECT: reduced wear capacity of the concrete. ^ 1 tbl

Description

The invention relates to building materials and can be used for the manufacture of concrete products in civil and industrial construction, monolithic construction, in concreting densely reinforced structures, as well as in the construction of structures for special purposes.

A known raw material mixture for the manufacture of high-strength concrete (Yu.M. Bazhenov. Concrete technology. Publishing House of the Association of Building Universities (DIA), Moscow, 2002, p. 377), containing Portland cement, silica-containing component, sand, gravel, silicate flour, additive and water.

The disadvantage of this technical solution is the increased value of abrasion.

Known raw material mixture for the manufacture of high-strength concrete (RU No. 2256629, C04B 28/04, published July 20, 2005) containing Portland cement, sand, gravel, a silica-containing component represented by orthosilicic acid sol with a density of 1.014 g / cm ³ , a hydrogen indicator 5-6, the supplement "DEYA-M" and water.

The disadvantage of this technical solution is the increased value of abrasion.

The closest in technical essence to the claimed invention is high-strength concrete (RU No. 2323910, C04B 28/04, 22/06, 111/20, publ.: 05/10/2008) containing Portland cement, sand, gravel, the additive is a hydroxide sol iron (III) with a density of 1.018 g / cm ³ , a hydrogen index of 4.5-5.5 and water in the following ratio of components, wt.%:

Portland cement 23.6-26.9 Sand 23.7-25.2 Crushed stone 36.8-38.4 Sol of iron (III) hydroxide with a density of 1.018 g / cm ³ , pH 4.5-5.5 0.7-0.76 Water 11.9-12.04

The disadvantage of this technical solution is the increased value of abrasion.

The problem to which the invention is directed, is the creation of high-strength concrete with a lower value of abrasion.

The technical result is achieved by the fact that in high-strength concrete, obtained from a mixture containing Portland cement, sand, gravel, additive and water, the additive is complex and consists of iron hydroxide sol (III) with a density of 1.021 g / cm ³ , a hydrogen index of 4.5 -5.5 and superplasticizer Muraplast FC 63, in the following ratio, wt.%:

Iron (III) hydroxide sol density ρ = 1,021 g / cm ³ , hydrogen indicator 4,5-5,5 85.50-86.00 Superplasticizer Muraplast FC 63 14.00-14.50

in the following ratio of components of the raw mix, wt.%:

Portland cement 20.60-27.40 Sand 21.80-24.70 Crushed stone 42.40-44.50 Specified Additive 0.70-0.90 Water 7.70-9.30

Comprehensive physicochemical studies showed that in the presence of this complex additive, the hydration activity of cement in the resulting concrete increases, mainly there is an increase in the degree of hydration of tricalcium silicate C ₃ S, which, of course, leads to an increase in strength and lower abrasion of activated concrete.

For the silicate component, the following changes are observed: the lines significantly decrease at an interplanar distance equal to (2.75; 2.73; 2.60; 2.18; 1.94; 1.76) × 10 ^-10 m, characteristic of alite, the main mineral of Portland cement, and at the same time, an increase in reflexes related to the formation of calcium hydroxide at an interplanar distance of (4.93; 2.63; 1.93) × 10 ^-10 m, as well as an increase in reflexes at an interplanar distance of (3 , 07; 2.80; 2.40; 2.10) × 10 ^-10 m, corresponding to the formation of tobermorite-like hydrosilicates. T.O. the proposed complex additive has a major effect on the hydration activity of only the silicate component of Portland cement.

The use of this sol-containing additive increases the strength of concrete, densifies the structure of artificial stone and reduces abrasion, since the proposed complex additive has an increased activating effect, providing increased hydration activity of the cement-containing hardening system.

The advantages of using the specified complex additives in comparison with the control non-additive composition and prototype are as follows:

- the best distribution of cement and micro-aggregate in the concrete mixture;

- lack of uncontrolled air intake;

- increase the uniformity and workability of concrete mixtures, including hard ones;

- obtaining high-strength and durable concrete with improved quality parameters;

- increase the strength of concrete in the initial and final periods of hardening;

- the possibility of reducing or completely eliminating heat treatment;

- obtaining self-compacting concrete;

- cost reduction during laying, distribution and compaction of concrete mix;

- improving the surface quality of finished products.

The abrasion of concrete activated by a complex admixture was evaluated in the following sequence described below.

The abrasion depends on the hardness of the material: the higher the hardness, the less abrasion. Abrasion is the ability of a material to decrease in mass and volume under the influence of abrasive forces.

To determine the abrasion of materials, a special abrasion wheel type LKI-3 (GOST 13087-81) was used and samples 10 × 10 × 10 cm in size were made. Abrasion, g / cm ² , was estimated by the loss of the initial mass of the material sample to the abrasion surface area and calculated according to the formula

where m ₁ is the mass of the sample before testing, g;

m ₂ - the same, after testing when passing the sample (4 × 150) m = 600 m of the test path, where 150 m corresponds to one test cycle.

As abrasive material, grinder No. 16 was used in accordance with GOST 3647-80, which was replaced 5 times for each cycle, i.e. every 30 m of the test path.

The abrasion test was performed on samples aged 28 days, the curing of which was carried out under normal conditions. A comparative assessment of the abrasion of the control and activated concrete is presented in the table.

An analysis of the data shows that the abrasion of activated concrete decreased by 43% and amounted to 57% relative to the uncontrolled control composition of concrete.

Analysis of the data obtained in the Table shows that the proposed complex additive has a plasticizing effect on the cement-containing system, reducing the amount of mixing water by 10%, while the water-cement ratio decreases, which contributes to the formation of a denser structure.

The result of the use of this complex additive is a decrease in the abrasion of concrete by 43% to a value of 0.51 g / cm ² .

At the filing date, according to the applicant, the claimed high-strength concrete is not known and this technical solution has world novelty.

The claimed combination of essential features exhibits a new property in the presence of an iron (III) hydroxide sol with a density of 1.021 g / cm ³ and a hydrogen index of 4.5-5.5 and Muraplast FC 63 superplasticizer, namely, it increases the mobility of the concrete mixture and also increases the hydration activity cement, the result of which is a decrease in the abrasion of concrete in comparison with the prototype.

The mixture, including Portland cement, sand and gravel and the proposed complex additive, provided high-strength concrete, characterized by reduced abrasion at design age (28 days) by 22% to a value of 0.36 g / cm ² compared with the prototype.

According to the applicant, the claimed invention meets the eligibility criterion of "inventive step".

The claimed invention is industrially applicable and can be used in civil and industrial construction, monolithic construction, in concreting densely reinforced structures, as well as in the construction of structures for special purposes.

Prepare the raw mix as follows.

3-4 drops of a saturated solution of iron chloride are added to 100 cm ^{3 of} boiling water. In this case, hydrolysis of iron chloride proceeds vigorously and the appearing molecules of iron hydroxide condense into colloidal particles. The resulting sol of iron hydroxide has a cherry-brown color.

Thus, a sol of iron hydroxide (III) is obtained with a density of 1.021 g / cm ³ , a hydrogen index of 4.5-5.5, which is a cherry-brown liquid.

The dosed sol and polycarboxylate-based Muraplast FC 63 superplasticizer manufactured by the Czechoslovak company (DIN EN ISO 9001) is placed in dosed water. Dispensed components of the raw material mixture: Portland cement M400, sand with a particle size module of 2.1, crushed stone fraction 5-10 mm and water containing a dosed complex additive is placed in a concrete mixer, where the components are mixed and the concrete mixture is prepared from which the required concrete products are made and samples for quality control by abrasion parameters.

Concrete hardening was carried out under normal conditions and the test results according to GOST 13087-81, GOST 3647-80 are presented in the table.

Analysis of the data presented in the table shows that the proposed high-strength concrete according to this invention reduces abrasion at design age (28 days) by 22% to a value of 0.36 g / cm ² compared with the prototype.

Claims (1)

High-strength concrete obtained from a raw material mixture containing Portland cement, sand, gravel, additive and water, characterized in that the additive is complex and consists of iron hydroxide sol (III) with a density of 1.021 g / cm ³ , a hydrogen index of 4.5-5 , 5 and superplasticizer Muraplast FC 63 in the following ratio of components, wt.%:
Iron (III) hydroxide sol a density equal to 1,021 g / cm ³ pH 4.5-5.5 85.50-86.00 Superplasticizer Muraplast FC 63 14.00-14.50
in the following ratio of components of the raw mix, wt.%:
Portland cement 20.60-27.40 Sand 21.80-24.70 Crushed stone 42.40-44.50 Specified Additive 0.70-0.90 Water 7.70-9.30