RU2378208C1 - Additive for concrete mix - Google Patents

Abstract

FIELD: construction. ^ SUBSTANCE: invention is related to construction materials and may be used as additive for concretes and construction mortars. Additive for concrete mixture contains wt %: after-yeast stillage with content of dry substances - 4.0-5.0 wt %, pH-5.0-6.0, density - 1.016 g/cm3 73.80-76.20, sodium fluoride 0.30-0.50, manganese dioxide 0.70-0.90, calcium hydroxide 0.70-0.90, microsilica with S"â"=2,000 m2/kg 22.10-23.90. ^ EFFECT: reduced water absorption, lower abradability and increased impact strength of concrete or construction mortar. ^ 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 and for special purposes.

Known additive for concrete mix (RU No. 2058947, С04В 28/00, bull. No. 12 from 04/27/96), consisting of citrogypsum and calcium citrate filtrate.

The disadvantage of this technical solution is the increased value of water absorption, a higher value of abrasion and a lower value of impact strength.

Known additive for concrete mix, consisting of potassium chromate and magnesium compounds (SU No. 827440, С04В 28/02 from 07/05/81).

The disadvantage of this technical solution is the increased value of water absorption, a higher value of abrasion and a lower value of impact strength.

Closest to the claimed additive for concrete mix is an additive (RU No. 2123482, С04В 28/00 from 06/19/97) containing post-yeast distillery with a solids content of 3.5-4.5 wt.%, The pH value is 4.5- 5.5, a density value of 1.014 g / cm ³ containing a modifier represented by an expanded porous product with a bulk density of 0.6 g / cm ³ in an amount of 3.0 ± 0.5 wt.%.

The disadvantage of this technical solution is the increased value of water absorption, a higher value of abrasion and a lower value of impact strength.

The objective of the invention is to create a new additive for concrete mix, the use of which would allow to achieve a technical result, consisting in improving the quality parameters of concrete, namely, lowering water absorption, lowering abrasion and increasing impact strength.

The task is achieved in that the additive for concrete mix includes post-yeast distillery stillage and a modifier represented by sodium fluoride, manganese dioxide, calcium hydroxide and silica fume with a specific surface - Ssp = 2000 m ² / kg, and the post-yeast stillage has a density of 1.016 g / cm ³ , pH - 5.0-6.0 solids content - 4.0-5.0 wt.%, with the following weight ratio of components, wt.%:

Post-yeast Bard 73.80-76.20 Sodium fluoride 0.30-0.50 Manganese Dioxide 0.70-0.90 Calcium hydroxide 0.70-0.90 Silica fume with Ssp = 2000 m ² / kg 22.10-23.90

A new, in comparison with the known additives in concrete, is the combination of the well-known post-yeast distillery stillage having a density of 1.016 g / cm ³ , pH-5.0-6.0, dry matter content - 4.0-5.0 wt.%, with a modifier consisting of sodium fluoride, manganese dioxide, calcium hydroxide and silica fume with Ssp = 2000 m ² / kg.

The use of manganese dioxide enhances the redox process in the system of post-yeast stillage vinasse - the filtrate, which leads to an increase in the nitrate form of nitrogen, which helps to enhance hydration processes; sodium fluoride has a preservative effect, i.e. blocks the residual process of mass fermentation, which underlies the production of the main yeast product, the waste of which is the post-yeast vinasse, and at the same time additionally enhances the activating effect of the filtrate; calcium hydroxide removes phosphorus-containing anions of PO ₄ ^3- from the filtrate, forming sparingly soluble compounds Ca ₃ (PO ₄ ) ₂ , finely dispersed silica fume acts as an adsorbent, on the surface of which reducing sugars, which are part of filtrates, interfere with hydration processes, as well as silica fume are adsorbed, acting as a microfiller, compacting the emerging structure of artificial stone.

Thus, the post-yeast distillery vinasse - a yeast filtrate in the presence of the specified modifier has an effective activating effect, which allows to achieve the desired technical result.

At the filing date, according to the authors and the applicant, the claimed admixture in the concrete mixture is not known and this technical solution has world novelty.

The claimed combination of essential features exhibits a new property: lower water absorption, lower abrasion and increased impact strength.

It is another property of the aggregate that is not equal to the known properties of the distinguishing features that allows us to recognize this aggregate as compared with the new solutions known in science and technology, and the claimed invention corresponds to the eligibility criterion - inventive step.

The claimed invention is industrially applicable and can be used for the manufacture of additives for concrete mix.

Concrete example

1. Preparation of the additive

Dose:

- leachate filtrate having a density of 1.016 g / cm ³ , pH 5.0-6.0, solids content of 4.0-5.0 wt.% ,;

- sodium fluoride;

- manganese dioxide;

- calcium hydroxide;

- finely divided silica fume with Ssp = 2000 m ² / kg.

The dosed components are transported to a mixer with a low-speed mixer, where mixing is carried out for 30 minutes and a ready-mixed concrete mix is obtained.

The finished product is transported in a vertical cone-shaped container equipped with a supply of compressed air for periodic bubbling of the additive, in order to prevent possible precipitation.

2. Preparation of concrete or mortar

Dose:

- additive in an amount of 1.3 wt.% by weight of cement;

- water;

- cement;

- sand;

- crushed stone.

The dosed additive is transported to the dosed mixing water and then all the dosed components are transported to the concrete mixer, where all components are thoroughly mixed; further preparation of the concrete mixture is carried out according to the technology adopted at the factory.

Evaluation of the effectiveness of the additive was carried out according to the parameters of water absorption according to GOST 12730.3-78 (1994) “Concretes. Method for the determination of water absorption "; abrasion according to GOST 13087-81 "Concrete. Methods for determining abrasion ”and impact strength, which is described below.

Impact (dynamic) strength is the property of a material to resist fracture under impact loads. It is characterized by the amount of work spent on the destruction of the standard sample, referred to the unit volume or cross-sectional area. Impact strength is determined in those cases when during operation the materials in the structures are subjected to dynamic influences: for example, in road and airfield coatings, machine foundations, floors of industrial buildings, sleepers.

Impact test is carried out on the copra. The most common is the Podge coper. Samples in the form of cylinders with a diameter and a height of 25 mm are tested on it. The pile driver consists of a massive support weighing about 50 kg, which also serves as an anvil, and two guide rods. A test piece is mounted on the anvil. A steel hammer weighing 2 kg moves along the guide rods. The hammer blow on the sample is carried out through a pod with a spherical surface so that the blow is transmitted strictly to the center of the upper face of the sample. The first blow is struck with a hammer falling from a height of 1 cm, the second from a height of 2 cm, the third from a height of 3 cm, etc. before the destruction of the sample, i.e. before the first crack appears.

An indicator of the resistance of the sample to impact is the serial number of the impact at which the sample is destroyed. Impact strength is calculated as the arithmetic average of the test results of three samples according to the formula:

where m is the mass of the hammer, kg;

n is the sequence number of the impact that destroyed the sample;

ν is the sample volume, cm ³ .

In this work, samples with a volume of 12.26 cm ³ were examined. The test samples were cylinders of size d = 2.5 cm and h = 2.5 cm, at the age of 28 days of normal hardening.

The results are presented in the table. The results obtained for concrete of class B22.5 composition corresponding to the ratio C: P: SC = 1: 2: 2.76 are presented in the table.

Analysis of the obtained data shows that when using the inventive additive, water absorption decreased by 19%, abrasion decreased by 21% and impact strength increased by 66%.

Claims (1)

Additive for concrete mixture, including post-yeast stillage and modifier, characterized in that it contains sodium fluoride, manganese dioxide, calcium hydroxide and silica fume with specific surface area Ssp = 2000 m ² / kg, and the post-yeast stillage has a density of 1.016 g / cm ³ , pH 5.0-6.0, solids content -4.0 - 5.0 wt.% in the following weight ratio of components, wt.%:
Post-yeast Bard 73.80-76.20 Sodium fluoride 0.30-0.50 Manganese Dioxide 0.70-0.90 Calcium hydroxide 0.70-0.90 Silica fume with Ssp = 2000 m ² / kg 22.10-23.90