RU2515261C1 - High-strength concrete - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: high-strength concrete contains portland cement, sand, crushed stone and water and a complex additive represented by sol of ferric hydroxide (III) with density equal to 1.021 g/cm³, hydrogen index 4.5-5.5 and additive Sika PerFin 300 at the following ratio of components, wt %: 14.50-15.00 and 85.00-85.50 accordingly, at the following ratio of components of a raw mix, wt %: portland cement 21.20-28.00; sand 21.80-24.70; crushed stone 42.40-44.50; specified additive 0.10-0.30; water 7.70-9.30.

EFFECT: reduced abradability of concrete.

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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.

Known raw mix for the manufacture of high-strength concrete (Yu.M. Bazhenov. Concrete technology. - M.: Publishing house of the Association of construction universities (DIA), 2002, p.377), containing Portland cement, silica-containing component, sand, gravel, silicate flour , supplement and water.

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

Known raw material mixture for the manufacture of high-strength concrete (RU No. 2256629, С04В 28/04, published on 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 of 5 -6, the addition of "DEYA-M" and water.

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

The closest in technical essence to the claimed invention is high-strength concrete (RU, No. 2323910, С04В 28/04, 22/06, 111/20, publ.: 05/10/2008), containing: Portland cement, sand, gravel, additive and water, the additive is complex and consists of an iron (III) hydroxide sol with a density of 1.021 g / cm ³ , a hydrogen index of 4.5-5.5 and a polycarboxylate-based Muraplast FC 63 superplasticizer manufactured by the Czechoslovak company (DIN EN ISO 9001) with the following ratio of components wt.%:

Sol of iron (III) hydroxide with 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

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

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 high-strength concrete obtained from a mixture containing Portland cement, sand, gravel, water and a complex additive consisting of sol of iron hydroxide (III) with a density of 1.021 g / cm ³ , a hydrogen index of 4.5-5.5 and a plasticizer, characterized in that as a plasticizer contains an additive Sika Perfin 300 in the following ratio, wt.%:

Sol of iron (III) hydroxide with density ρ = 1,021 g / cm ³ , hydrogen indicator 4,5-5,5 14.50-15.00 Sika PerFin 300 Supplement 85.00-85.50

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

Portland cement 21.20-28.00 Sand 21.80-24.70 Crushed stone 42.40-44.50 Specified Additive 0.10-0.30 Water 7.70-9.30

The developed complex additive gives an extra-cumulative effect in the production of high-strength concrete, which is expressed in the fact that the proposed high-strength concrete according to this invention has reduced abrasion at design age.

Conducted comprehensive physico-chemical studies have shown that in the presence of the specified complex additives increases the hydration activity of cement. Basically, there is an increase in the degree of hydration of tricalcium silicate C ₃ S, which results in an increase in strength and lower abrasion of the developed concrete.

For the silicate component, the following changes are observed: the lines significantly decrease at d / n = (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 also there is an increase in reflexes at d / n = (4.93; 2.63; 1.93) × 10 ^-10 m, related to the formation of calcium hydroxide and an increase in reflexes at d / n = (3.07 ; 2.80; 2.40; 2.10) × 10 ^-10 m, corresponding to the formation of tobermorite-like hydrosilicates. Thus, the proposed complex additive has a major effect on the hydration activity of only the silicate component of Portland cement.

The use of this complex sol-containing additive provides a densification of the structure of artificial stone and a reduction in abrasion, since the proposed complex additive has an increased activating effect, providing an increase in the hydration activity of the cement-containing hardening system.

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

- a significant reduction in the number of air pores in concrete and, as a result, the absence of shells and other defects on the concrete surface;

- ensuring high surface quality;

- the absence of a negative effect on the properties of concrete mix and concrete;

- the possibility of manufacturing high-quality architectural concrete;

- reduction or elimination of costs for subsequent refinement and repair of structures or reinforced concrete products.

The abrasion of concrete activated by the proposed complex additive was evaluated in the 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 LKI-3 type abrasion circle machine (GOST 13087-81) was used and samples 10 × 10 × 10 cm in size were made. Abrasion, g / cm ² , estimated by the loss of the initial mass of the material sample to the abrasion surface area and according to the formula:

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

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

F is the surface area of the sample, cm ² .

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, the results are presented in the table.

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

Sika Perfin 300 additive is a light yellow liquid based on a modified polyhydric alcohol with a density of ρ = 1,000 g / cm ³ and a hydrogen index of 3.2–4.2 (according to the manufacturer’s passport, Zika LLC, a structural unit of the Swiss concern Sika).

The effectiveness of the Sika PerFin-300 additive depends on the concrete formulation, on the formwork and formwork lubrication, it does not contain chlorides and other substances that cause steel corrosion, it can be used in the manufacture of reinforced concrete and prestressed concrete structures.

The claimed combination of essential features exhibits a new property in the presence of a complex additive consisting 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 Sika Perfin 300 additive, increases the hydration activity of cement, resulting in 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 14% to a value of 0.23 g / cm ² compared with the prototype.

According to applicants and authors, the claimed invention meets the eligibility criteria - 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.

The raw mix is prepared 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 (III) hydroxide condense into colloidal particles. The resulting sol of iron (III) hydroxide has a cherry-brown color.

Dosage sol and Sika Perfin 300 are placed in dosed water. Dispensed components of the raw mix: Portland cement M400 D20, sand with a particle size module of 2.1, crushed stone fractions of 5-10 mm and water containing a dosed complex additive is placed in a concrete mixer, where the components are mixed and the concrete mix is prepared, from which the required concrete products are made and samples for quality control in terms of abrasion.

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 14% to a value of 0.23 g / cm ² compared with the prototype.

Claims (1)

High-strength concrete obtained from a mixture containing Portland cement, sand, gravel, water and a complex additive consisting of an iron (III) hydroxide sol with a density of 1.021 g / cm ³ , a hydrogen index of 4.5-5.5 and a plasticizer, characterized the fact that as a plasticizer contains Sika Perfin 300 additive in the following ratio of components, wt.%:
Sol of iron (III) hydroxide with density ρ = 1,021 g / cm ³ , hydrogen indicator 4,5-5,5 14.50-15.00 Sika PerFin 300 Supplement 85.00-85.50
in the following ratio of components of the raw mix, wt.%:
Portland cement 21.20-28.00 Sand 21.80-24.70 Crushed stone 42.40-44.50 Specified Additive 0.10-0.30 Water 7.70-9.30