RU2377211C1 - Additive for concrete mixture - Google Patents

Abstract

FIELD: building. ^ SUBSTANCE: invention refers to building materials and can be implemented in industrial and civic engineering at preparation of concrete and reinforced concrete items and also at construction of buildings of special purpose. The additive for concrete mixture contains, wt %: micro-silica with specific surface Ssp=2000 m2/kg - 60.60-62.40; super-plasticiser C-3 - 4.25-4.55, sodium nitrite - 2.75-3.03; sol of iron hydroxide (III) - 1.46-1.52; open-hearth furnace dust with contents of Fe (III) not less 60 wt % and Zn (II) not more 1.0 wt % - 29.14-30.30. ^ EFFECT: upgraded durability at compression, reduced shrinkage and abrasiveness. ^ 1 ex, 1 tbl

Description

The invention relates to the production of concrete of different densities and mortars and can be used in industrial and civil engineering in the manufacture of concrete and reinforced concrete products, as well as in the construction of structures for special purposes.

Known additive for concrete mix, which includes sludge galvanic production (patent RU No. 94003947 С04В 28/00 publ. 10.20.1995,).

The disadvantage of this technical solution is the lack of compressive strength, the increased value of shrinkage and abrasion.

Known additive for concrete mix, which includes potassium chromate and magnesium compounds (SU No. 827440, С04В 28/02, publ. 07.05.1981).

The disadvantage of this technical solution is the lack of compressive strength, the increased value of shrinkage and abrasion.

Closest to the invention in terms of essential features is an additive for concrete mix, which includes silica fume, superplasticizer C-3 and sodium nitrite in the following ratio of components, wt.%:

Silica fume 10.00-21.00 Superplasticizer S-3 14.00-32.00 Sodium nitrite 47.00-75.00

(Patent RU No. 2308429, C04B 24/30, publ. 20.10.2007).

The disadvantage of this technical solution is the lack of compressive strength, the increased value of shrinkage and abrasion.

The problem to which the invention is directed, is to create a new additive for concrete mix, using which a technical result would be obtained consisting in increasing compressive strength, reducing shrinkage and abrasion.

The technical result is achieved by the fact that the additive for concrete mix includes silica fume with Ssp = 2000 m ² / kg, C-3 superplasticizer, sodium nitrite and additionally contains iron (III) hydroxide sol and open-hearth dust with an Fe (III) content of ≥60 wt. % and Zn (II) ≤1.0 wt.%, with the following weight ratio of components, wt.%:

Silica fume with Ssp = 2000 m ² / kg 60.60-62.40 Superplasticizer S-3 4.25-4.55 Sodium nitrite 2.75-3.03 Sol of iron (III) hydroxide 1.46-1.52 Open-hearth dust with content Fe (III) ≥60 wt.% And Zn (II) ≤1.0 wt.% 29.14-30.30

The introduction of the inventive additives in the concrete mixture increases the hydration activity of cement by the catalytic mechanism of action due to the displacement of acid-base equilibrium in the hardening system.

The combined presence of a sol of iron (III) hydroxide, open-hearth dust with an iron (III) content in an amount of ≥60 wt.% And Zn (II) in an amount of ≤1.0 wt.% And silica fume provides an extra sum effect, which is expressed in an increase in hydration cement activity due to a shift in the redox equilibrium in the cement-containing system, i.e. Δφ arises because the electrode potential of the additive is φ = + 220 mV, and that of the cement-containing system is φ = + 180 mV. As a result of an increase in the hydration activity of cement with a reduced W / C ratio in the presence of silica fume, the claimed technical result is achieved, which is expressed in an increase in compressive strength, a decrease in shrinkage and abrasion.

In the presence of the inventive additive, a more dense artificial stone structure is formed due to blocking of pores by iron (III) hydroxide particles of 10 ^-7 -10 ^-9 cm in size, as well as hydrated compounds formed in an increased amount, represented by low-basic hydrosilicates having a fibrous structure, and larger pore particles of silica fume with a size of 10 ^-4 -10 ^-5 cm

The changes in the structure of artificial stone in the presence of the inventive additives contribute to increased compressive strength, reduced shrinkage and abrasion.

The specified set of essential features at the filing date of the application is unknown to the applicant, therefore, the applicant believes that the claimed invention meets the eligibility criteria of “novelty”.

The claimed combination of essential features exhibits a new enhanced action relative to the prototype, consisting in obtaining highly efficient concrete, namely: characterized by an increased value of compressive strength by 72%, a decrease in shrinkage by 25% and abrasion by 27%.

Therefore, the invention meets the eligibility criterion of "inventive step".

The claimed invention meets the eligibility criterion of "industrial applicability", as it is suitable for use in the production of concrete and reinforced concrete products and is feasible, as evidenced by specific examples.

An example of a specific implementation:

1. Preparation of the supplement.

Dose:

- open-hearth dust with a content of Fe (III) ≥60 wt.% and Zn (II) ≤1.0 wt.%;

- silica fume with a specific surface Ssp = 2000 m ² / kg;

- sol of iron (III) hydroxide.

The dosed components are sent to a vertical mixer with a low-speed mixer and mixed for 30 minutes.

The resulting finished product is stored in vertical cone-shaped containers equipped with air for periodic bubbling to prevent possible precipitation.

2. Preparation of activated concrete mix.

The introduction of additives in concrete is as follows: the finished additive is dosed in an amount of 6 wt.% By weight of cement; the dosed additive is poured into the dosed water to prepare the concrete mixture. Next, the concrete mixture is prepared according to the technology adopted at the factory; the effectiveness of the additive was evaluated by changing the physical and mechanical characteristics of traditional concrete B22.5 as the most common, of the following composition:

C: P: N = 1: 2.19: 3.03.

Strength was evaluated according to GOST 10180-90, shrinkage according to GOST 24544-81 and abrasion according to GOST 13087-81.

The results of the study are presented in the table. Analysis of the data in the table shows that the introduction of the new inventive additives in the concrete mixture increases compressive strength by 72%, reduces shrinkage by 25% and abrasion by 27%.

Claims (1)

Additive for concrete mix, including silica fume, superplasticizer C-3 and sodium nitrite, characterized in that it contains silica fume with a specific surface Ssp = 2000 m ² / kg and additionally contains an iron (III) hydroxide sol and open-hearth dust containing Fe (III ) not less than 60 wt.% and Zn (II) not more than 1.0 wt.% in the following weight ratio of components, wt.%:
Silica fume with Ssp = 2000 m ² / kg 60.60-62.40 Superplasticizer S-3 4.25-4.55 Sodium nitrite 2.75-3.03 Sol of iron (III) hydroxide 1.46-1.52 Open-hearth dust with content Fe (III) not less than 60 wt.% And Zn (II) no more than 1.0 wt.% 29.14-30.30