RU2278837C1 - Complex additive for concrete mix - Google Patents

Abstract

FIELD: manufacture of building materials; manufacture of reinforced concrete articles.

SUBSTANCE: complex additive for concrete mix includes commercial ligno-sulfonate and trisodium phosphate in the amount of 0.4 % of cement mass at the following ratio of components, mass-%: ligno-sulfonate, 30-50; trisodium phosphate subjected to mechanical activation, 50-70; it is preferable that mix contains 50 of ligno-sulfonate and 50 of trisodium phosphate and at least one of the following components: natural zeolite, silica, zeolite process waste, sodium bichromate, potassium bichromate, sodium thiosulfate in the amount of up to 3 mass-% which is subjected to mechanical activation to size of particles not exceeding 10 mcm preferably with trisodium phosphate; commercial ligno-sulfonate is granulated.

EFFECT: enhanced plasticity and strength after steaming; reduced consumption of water; enhanced corrosion protection of reinforcement.

6 cl, 3 tbl

Description

The invention relates to building materials, to the compositions of complex additives and can be used in the production of concrete and reinforced concrete products.

Known plasticizing additive for concrete mix, consisting of technical lignosulfonate with a mineral adsorbent, which is used as peat ash (Patent RU No.2018496, IPC ⁷ C 04 V 24/18, publ. 30.08.94).

The disadvantage of this additive is the inconvenience of its use in liquid form, the low quality of the plasticizer due to the unstable composition.

Known liquid complex additive for concrete mix (A. S. SU 1636378, C 04 B 24/18, publ. 23.03.91), including technical lignosulfonates, phosphoric acid salt and water in a certain ratio.

The disadvantage of this additive is the low strength of concrete and the disadvantages inherent in liquid additives.

Known additive for concrete mix, including the waste of caprolactam production and technical lignosulfonate, which allows to improve the quality indicators of concrete and products based on it (Patent RU No. 2209792, IPC ⁷ C 04 B 28/02, publ. 08.10.2003).

The disadvantage of this additive is also not high enough strength of the resulting products from concrete and concrete.

Known complex additive for concrete mixture and the method of its preparation (Patent RU No. 2144519, IPC ⁷ C 04 B 28/04, publ. 01.20.2000). To prepare the additives, the mineral filler, plasticizer and inorganic hardening accelerator and gypsum are mixed in a certain ratio and ground to a specific surface of 2000-6000 cm ² / g.

The disadvantage of this mixture is the insufficiently high strength of the resulting concrete.

Known complex additive, including sulfite-yeast mash and trisodium phosphate, in amounts of 0.2 and 1%, respectively, of the mass of cement (Alimov TS and others. Concretes modified by the addition of trisodium phosphate. - "Concrete and reinforced concrete", 1982, No. 2 , p. 26-27).

However, this additive does not provide sufficient concrete strength after steaming. The additive is consumed in significant quantities by weight of cement.

 Closest to the invention in technical essence and technical result achieved is a complex additive containing a mixture of sulfate-alcohol stillage and trisodium phosphate, in amounts of 0.1-0.15% and 0.02-0.1% of the weight of mineral binder, respectively S. USSR No. 425868, IPC C 04 B 13/24, publ. 04/30/1974).

However, this additive also does not provide sufficient concrete strength after steaming.

The problem solved by the present invention is the development of the optimal composition of a complex additive obtained by simple technology from available components and introduced into concrete mixtures to improve the quality indicators of concrete and products based on it.

The problem is solved using a comprehensive additive for concrete mix, including technical lignosulfonate and trisodium phosphate. The amount of additive is 0.4% by weight of cement and it contains trisodium phosphate subjected to mechanical activation, in the following ratio of components, wt. %:

lignosulfonate 30-50 trisodium phosphate 50-70

Preferably, the additive contains these components in the following ratio, wt.%:

Lignosulfonate fifty Trisodium phosphate fifty

The additive may additionally contain at least one component: natural zeolite, silica, waste from the production of zeolite, sodium dichromate, potassium dichromate, sodium thiosulfate in an amount of up to 3 wt.%.

The additive may contain the above at least one component subjected to mechanical activation to a particle size of not more than 10 microns.

The additive preferably contains said at least one component subjected to said mechanical activation together with trisodium phosphate.

The additive preferably contains granular technical lignosulfonate.

When developing complex additives, one of the requirements that they must meet is to give concrete mixtures and solutions plasticity (mobility).

The technical result obtained by using the proposed complex additives is to increase the ductility of concrete mixtures and increase the strength of concrete after steaming, reduce water consumption and the amount of added additives in the concrete mixture, ensuring the protection of the reinforcement from corrosion.

In the proposed additive, in contrast to the known additive, a new quantitative composition of the additive was found, which, upon mechanical activation of trisodium phosphate, allowed to obtain an unexpected technical result: a significant increase in the strength of concrete, including after steaming, an increase in the ductility of concrete mixtures, a decrease in the amount of water, a decrease in the amount of the additive and a decrease corrosion reinforcement.

Tests and studies have shown that the total effect of the complex additive on cement systems is greater than the sum of the effects of each of them taken separately. Table 1 shows the composition of the additives. Table 2 shows the plasticity (mobility) characteristics of the concrete mixture depending on the amount of water. Table 3 shows the effect of the composition of the additives on the strength properties.

The proposed complex additive is obtained by joint mixing of technical lignosulfonate with trisodium phosphate.

Trisodium phosphate is crushed beforehand in a planetary screw mixer, then trisodium phosphate is transported from the mixer to a vibrocentrifugal mill, to which additional components are also fed if necessary. The mill produces grinding to the desired particle size of the additive. Additional components may be pre-milled to a particle size of less than 10 microns.

The complex additive is given the code name Benotech Siplast.

The concrete mixture is prepared according to the following method: cement and aggregates are introduced into the mixer and intensively mixed into the resulting dry mixture, a complex additive is added in an amount of 0.4% by weight of cement and the mixture is mixed until homogeneous. Then, concrete products are prepared according to the standard method for manufacturing laboratory-type samples.

For the preparation of the concrete mixture, cement was used - PC400, manufacturer of Iskitmcement OJSC; sand with M _cr = 2.15, pollution 1.2% - manufactured by AOZT Severo-Krivodanovsky Pit; crushed stone-diabase fraction 5-20 mm - manufacturer JSC "Stone quarry" p. Gorny.

The cone draft was determined according to GOST 10181-2000, item 4.

Three series of samples for testing at the age of 1 day after steaming, 7 days of hardening samples under normal conditions, 28 days of hardening samples under normal conditions were made of concrete mixes of each composition.

Tests of samples, storage conditions and tests were carried out in accordance with the requirements of GOST 10180-90.

Studies have shown that with the introduction of the proposed additives in an amount of 0.4% by weight of cement with the same w / c, the mobility of the concrete mixture increases without compromising strength. When mobility is achieved in comparison with the control sample, water consumption is reduced by 10% with a significant increase in strength.

With the introduction of the additive, the cone sludge increases by about 13.1 and amounts to 22.7 cm, that is, with the introduction of the additive, the mobility (plasticity) of the concrete mixture increases by about 2 times compared with the known solution.

With the introduction of the Benotech Siplast additive, the concrete mix according to the results of measurements of the draft of the cone and the spread of the cone is referred to the workability grade P5.

The proposed complex additive neutralizes the negative effect of sulphite-yeast mash on the known solution on the growth of strength of steamed concrete, while protecting the reinforcement from corrosion due to the inhibitory effect of trisodium phosphate.

Claims (6)

1. A comprehensive additive for concrete mix, including technical lignosulfonate and trisodium phosphate, characterized in that its amount is 0.4% by weight of cement and it contains trisodium phosphate subjected to mechanical activation, in the following ratio, wt.%: Lignosulfonate 30-50 Trisodium phosphate 50-70 2. The additive according to claim 1, characterized in that it contains these components in the following ratio, wt.%: Lignosulfonate fifty Trisodium phosphate fifty 3. The additive according to claim 1, characterized in that it additionally contains at least one component: natural zeolite, silica, waste products of the zeolite, sodium dichromate, potassium dichromate, sodium thiosulfate, in an amount up to 3 wt.%. 4. The additive according to claim 3, characterized in that it contains the specified at least one component subjected to mechanical activation to a particle size of not more than 10 microns. 5. The additive according to claim 4, characterized in that it contains the specified at least one component subjected to the specified mechanical activation together with trisodium phosphate. 6. The additive according to claim 1, characterized in that it contains granular technical lignosulfonate.