RU2515255C1 - High-strength concrete - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: high-strength concrete produced from a mix containing portland cement, sand, crushed stone and water and a complex additive containing sol of ferric hydroxide (III) with density equal to 1.021 g/cm³, hydrogen index 4.5-5.5 and plasticiser, differing by the fact that as a plasticiser it contains a superplasticiser Sika 1+, at the following ratio of components, wt %: 11.50-12.00 and 88.00-88.50 accordingly, at the following ratio of components of a raw mix, wt %: portland cement 21.60-28.40; sand 21.80-24.70; crushed stone 41.60-43.40; specified additive 0.50-1.00; water 7.70-9.30.

EFFECT: increased water impermeability 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 critical structures of special structures exposed to adverse external influences.

Known raw mix 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 lower value of the water resistance of concrete.

Known raw mix for the manufacture of high-strength concrete (RU No. 2266629, С04В 28/04, published: 07/20/2005), 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 5.0-6.0, the addition of "Deya-M" and water.

The disadvantage of this technical solution is the lower value of the water resistance of concrete.

The closest in technical essence to the claimed invention is high-strength concrete (RU No. 2433097, С04В 28/04, 22/06, 111/20, publ.: 10.11.2011), containing: Portland cement, sand, gravel, additive and water , where 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 the TsMID-4Zh superplasticizer, produced in the form of a 30% dark brown liquid - concentration (TU 5745-002-53268843-00, certificate of conformity No. РОСС RU.СЛ38.Н00124, hygiene certificate No. 78.01.06.574.P.0050 10/18/03), with the following the ratio of components, wt.%:

Sol of iron (III) hydroxide with density ρ = 1,021 g / cm ³ , pH 4.5-5.5 25.50-26.00 Superplasticizer "TsMID-4Zh" 74.00-74.50

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

Portland cement 20.60-27.40 Sand 21.80-24.70 Crushed stone 41.60-43.40 Specified Additive 1,50-2,00 Water 7.70-9.30

The disadvantage of this technical solution is the lower value of the water resistance of concrete.

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

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 iron (III) hydroxide sol with a density equal to 1.021 g / cm ³ and a hydrogen index of 4.5- 5.5, and a plasticizer, characterized in that the plasticizer contains a Sika 1+ superplasticizer, in the following ratio, wt.%:

Sol of iron (III) hydroxide with density ρ = 1,021 g / cm ³ , pH 4.5-5.5 11.50-12.00 Sika 1+ supplement 88.00-88.50

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

Portland cement 21.60-28.40 Sand 21.80-24.70 Crushed stone 41.60-43.40 Specified Additive 0.50-1.00 Water 7.70-9.30

According to the differential thermal analysis method (hereinafter DTA) of the prototype, control sample and developed concrete, the samples of the latter, in comparison with the prototype, show an increase in endo effects in the regions of 135-190 ° C and 370 ... 400 ° C, which correspond to the loss of physical and chemically bound water with low basic calcium hydrosilicates. The introduction of the specified complex additives into the cement system leads to even greater growth of chemically bound water compared to the prototype, which indicates an increase in the degree of cement hydration in the developed concrete. Judging by the change in the degree of hydration by the total weight loss in the case of developed concrete, the total weight loss increases by 14% compared with the prototype.

Differential thermal studies were performed using a Hungarian derivatograph type Q-1500D SYSTEM:

F. PAULIK, J. PAULIK, L. ERDEY. Research was carried out in inert crucibles. The atmosphere in the furnace is air, pressure is atmospheric. The work was carried out in the temperature range from 20 to 1000 ° C at a speed of 9-10 ° C per minute. Samples of the test material for DTA were prepared as follows: the test sample was ground into powder, which was passed through a sieve No. 0063 / 10,000 holes / cm ² . The size of the sample ranged from 0.9 to 1.4 grams. The heating rate was 9 ° C per minute. Heating was carried out to a temperature of 930 ° C. Before starting the study of each new series of samples, the sensitivity of the measuring device was adjusted. In each series, 3 samples were studied, which made it possible to identify the obtained thermograms with sufficient reliability.

Further research is devoted to assessing the water resistance of the developed concrete. For this purpose, cylinder samples of d = 15 cm and h = 15 cm size (diameter and height, respectively) were made in the amount of 6 pieces for each test, the curing of which was carried out under normal conditions for 28 days. Assessment of water resistance was carried out according to GOST 12730.5-84 according to the “wet spot” method, in accordance with which water is supplied to the lower end surface of the samples with increasing pressure. The observation was carried out for the upper surface of the samples, the results are presented in the table.

At the filing date, in the opinion of the author and 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 Sika 1+ additive, namely, it increases the water resistance of concrete.

The mixture, including Portland cement, sand, gravel and the proposed complex additive, provided high-strength concrete, characterized by an increased value of water resistance at the design age (28 days) by 20% to a value of 2.0 MPa compared to the prototype.

According to the author and the applicant, the claimed invention meets the eligibility criterion - 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 critical structures of special structures that are exposed to adverse external influences.

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.

The Sika 1+ additive based on amino alcohols with a density ρ = 1,020 g / cm ³ and a hydrogen index of 7.5–9.5 is a red liquid additive (according to the manufacturer’s passport, Zika LLC, a structural unit of the Swiss concern Sika).

Sika 1+ additive does not contain chlorides or other substances that cause corrosion of reinforcement, therefore this additive can be used without any restrictions for reinforced concrete structures, including prestressed ones.

Dosed sol and Sika 1+ 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 water resistance.

Concrete hardening was carried out under normal conditions, and the test results, according to GOST 12730.5-84, are presented in the table.

Analysis of the data presented in the table shows that the proposed high-strength concrete according to this invention increases the water resistance at the design age (28 days) by 20% to a value of 2.0 MPa compared to 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 and a hydrogen index of 4.5-5.5, and a plasticizer , characterized in that as a plasticizer contains a Sika 1+ superplasticizer, in the following ratio of components, wt.%:
Sol of iron (III) hydroxide with density ρ = 1,021 g / cm ³ , pH 4.5-5.5 11.50-12.00 Sika 1+ supplement 88.00-88.50
in the following ratio of components of the raw mix, wt.%:
Portland cement 21.60-28.40 Sand 21.80-24.70 Crushed stone 41.60-43.40 Specified Additive 0.50-1.00 Water 7.70-9.30