RU2573503C1 - High-strength concrete - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: high-strength concrete, produced from the mixture, containing portland cement, sand, crushed stone, water and complex additive, consisting of liquid sodium glass with the density ρ=1.45 g/cm³, hydrogen index pH=12.0 and iron hydroxide sol (III) Fe(OH)₃, with the density ρ=1.021 g/cm³ and hydrogen index pH=4.5-5.5, at the following ratio of components, wt %: 84.00-85.50 and 14.50-16.00 accordingly, at the following ratio of the mixture components, wt %: portland cement 19.50-26.65; sand with the modulus of fineness Mf=2.1 21.80-24.70; crushed stone of fraction 5-10 mm 42.40-44.50; specified additive 1.75-2.25; water 7.40-9.05.

EFFECT: reduced water absorption of concrete.

1 tbl

Description

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

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

The disadvantage of this technical solution is the increased value of water absorption 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, crushed stone, silica-containing component represented by H ₂ SiO ₃ sol with density ρ = 1,014 g / cm ^3, pH = 5-6, the additive "Dai-M" and water.

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

The closest in technical essence to the claimed invention is high-strength concrete (RU No. 2256630, С04В 28/04, published on July 20, 2005), containing: Portland cement, sand, gravel, silica-containing component, represented by H ₂ SiO ₃ sol with a density ρ = 1.014 g / cm ³ , pH = 5-6, the additive is potassium ferruginous K ₄ Fe (CN) ₆ and water in the following ratio of components, wt. %:

Portland cement 43.58-47.08 Sand 14.43-15.69 Crushed stone 25.70-27.84 Silica-containing component represented by H ₂ SiO ₃ sol with density ρ = 0.25-0.27 1.014 g / cm ³ , pH = 5-6 Additive - potassium ferruginous 0.44-0.47 K ₄ Fe (CN) ₆ Water 12.10-12.15

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

The problem to which the invention is directed, is to reduce the water absorption of concrete.

The task is achieved in that the high-strength concrete obtained from the mixture contains Portland cement, sand with a fineness modulus Mk = 2.1, crushed stone fractions of 5-10 mm, water and a complex additive, which consists of liquid sodium glass with a density ρ = 1, 45 g / ^cm3 pH value pH = 12,0 and a sol of iron hydroxide (III) Fe (OH) ₃ with a density of ρ = 1,021 g / cm ³ and a pH value pH = 4,5-5,5, with the following ratio components, wt. %:

Liquid sodium glass a density of 1.45 g / cm ³ pH value = 12.0 84.00-85.50 Sol of iron (III) hydroxide Fe (OH) ₃ with a density ρ = 1,021 g / cm ³ , pH value = 4.5-5.5 14.5-16.00

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

Portland cement 19.50-26.65 Indicated sand 21.80-24.70 Specified crushed stone 42.40-44.50 Specified Additive 1.75-2.25 Water 7.40-9.05

Long-life high-strength concrete must be impervious to external influences, which is achieved by increasing its density. Penetration of liquid substances of varying degrees of aggressiveness into concrete is determined by the permeability of concrete, which is one of its important characteristics. In insufficiently dense reinforced concrete, the penetration of moisture and air causes corrosion of the reinforcement, which increases in volume and, as a result, leads to cracking and destruction of the protective layer of concrete in the structure. The movement of water through the thickness of concrete is determined not only by pressure, but also by the moisture gradient on opposite surfaces of concrete, i.e. osmotic effect.

A sol of iron (III) hydroxide Fe (OH) ₃ with a density ρ = 1.021 g / cm ³ and a pH value of pH = 4.5-5.5 has a colloidal particle with a positive charge, which helps to enhance hydration processes in the hardening system. The presence of acceptor orbitals in the introduced colloidal particles with a positive charge promotes their interaction with water molecules and an increase in the concentration of protons in the system, which will interact with the main centers of the cement surface α ^/ according to Lewis:

The presented schemes indicate an increase in the hydration activity of cement in the presence of a sol of iron (III) Fe (OH) ₃ hydroxide. The presence of a sol of iron (III) Fe (OH) ₃ hydroxide in the hardening system promotes the formation of fibrous silicates of the CSH (I) type, and, as a result, their presence increases the density of concrete.

In addition, the sol of iron (III) hydroxide Fe (OH) ₃ has a plasticizing effect on the cement mixture, reducing the amount of mixing water by 10%, while it contributes to the formation of a dense structure, while also providing increased compressive strength, tensile bending and impact durability of the made concrete.

Liquid sodium glass with a density of 1.45 g / cm ³ according to GOST 13078-81 in combination with a sol of iron (III) hydroxide sol with a density ρ = 1.021 g / cm ³ and a pH of 4.5-5.5 gives an extra total the effect, which is expressed in the formation of tobermorite-like hydrosilicates and, as a result, obtaining high-strength concrete with increased density by water absorption compared to the prototype.

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

According to the authors and the applicant, the claimed invention meets the eligibility criteria - inventive step.

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

A sol of iron (III) hydroxide Fe (OH) _{3 is} prepared as follows: 3-4 drops of a saturated solution of FeCl ₃ 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 [Barvinok MS, Garbudova TF Colloids. L .: LIIZHT, 1970 .-- 16 p .; Korovin N.V. General chemistry. M .: Higher school, 2000. - 558 p.].

The raw mix is prepared as follows: at the place of work, the factory soluble liquid sodium glass is diluted with water to the desired concentration, namely, to normal liquid sodium glass with a density of 1.45 g / cm ³ according to GOST 13078-81. Then the dosed sol of iron (III) hydroxide {mFe (OH) ₃ · nFe ⁺³ · (3n-x) · Cl ^-1 } ^{+ x} ... · Cl ^-1 [Barvinok MS, Garbudova TF Colloids. L .: LIIZHT, 1970 .-- 16 p .; Korovin N.V. General chemistry. M .: Higher school, 2000. - 558 p.] Placed in dosed liquid glass. Dosed components of the raw material mixture: Portland cement M400, sand with a particle size module of 2.1, crushed stone of the 5-10 mm fraction and water containing a dosed additive are placed in a concrete mixer, where the components are mixed and the concrete mixture is prepared, from which the required concrete products and samples are made for quality control by density parameters for water absorption.

Concrete hardening was carried out under normal conditions and the test results, according to GOST 12730.3-78 "Method for determining water absorption", are presented in the table.

Analysis of the data presented in the table shows that the proposed high-strength concrete according to this invention is characterized by reduced water absorption by 8% and is 1.6% compared to the prototype.

Claims (1)

High-strength concrete obtained from a mixture containing Portland cement, sand, crushed stone, water and a complex additive, characterized in that the mixture for high-strength concrete contains sand with a fineness modulus Mk = 2.1, crushed stone fraction 5-10 mm, a complex additive consisting of liquid sodium glass with a density ρ = 1.45 g / cm ³ , a hydrogen pH = 12.0 and a sol of iron (III) Fe (OH) ₃ hydroxide with a density ρ = 1.021 g / cm ³ and a hydrogen pH = 4, 5-5.5, in the following ratio of components, wt. %:
Liquid sodium glass a density of 1.45 g / cm ³ pH value = 12.0 84.00-85.50 Sol of iron (III) hydroxide Fe (OH) ₃ with a density ρ = 1,021 g / cm ³ , pH value = 4.5-5.5 14.5-16.00
in the following ratio of components of the mixture, wt. %:
Portland cement 19.50-26.65 Indicated sand 21.80-24.70 Specified crushed stone 42.40-44.50 Specified Additive 1.75-2.25 Water 7.40-9.05