RU2525565C1 - Concrete mixture - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: concrete mixture includes Portland cement, crushed granite, quartz sand, a microfiller, a superplasticiser based on polycarboxylates and water. Additionally into the mixture introduced is TTP fly ash, as the microfiller used is ground limestone MP-1, and as the superplasticiser, based on polycarboxylates MC-RowerFlow 2695, with the following component ratio, wt %: Portland cement 8-10, ground limestone MP-16-8, TPP fly ash 3-6, quartz sand with the coarseness module Mc 1.9 30-40, crushed granite of fraction 3-10 mm 15-18, crushed granite of fraction 5-20 mm 14-16, the superplasticiser based on polycarboxylates MC-RowerFlow 2695 0.0015-0.003, water - the remaining part.

EFFECT: increase of concrete quality due to increased fluidity of the concrete mixture and its self-compaction.

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Description

The invention relates to the composition of the raw material mixture for producing concrete with increased density, the absence of large pores reduces the risk of corrosion of concrete, which increases the durability of concrete, and the possibility of using it in an aggressive environment and can be used to produce high quality concrete.

The patent is known: “Concrete composition” for the production of structural materials, shotcrete and cementing works, containing Portland cement, S-3 superplasticizer, condensed silica fume with a specific surface of (15-25) · 10 ³ cm ² / g, quartz sand fraction less than 0.14 mm and 1.25-2.50 mm, ground quartz sand with a specific surface area (3.5-4.0) · 10 ³ cm ² / g, a complex additive is a product of joint intensive dry grinding to a specific surface (4.0- 4.5) x 10 ³ cm ² / g aluminate cement clinker mark "500" or "600" fraction with trehkal tsievogo aluminate C ₃ Al therein 8-12% quartz sand with a specific surface (1.5-2.5) x 10 ³ cm ² / g, and a dry powder superplasticizer C-3, in the ratio 5: 4: 1 respectively , the reinforcing component is chrysotile asbestos and grinding dust is a waste product of asbestos industrial products and water in the following ratio of components, wt.%:

Portland cement 24.0-25.0 The specified silica fume 4.0-5.5 Quartz sand fractions less than 0.14 mm 20.0-21.0 Quartz sand fraction 1.25-2.50 mm 28.0-31.0 Superplasticizer S-30, 4-0.8 Specified Ground Quartz Sand 6.5-8.0 Specified complex additive 2.5-3.0 Asbestos chrysotile 0.6-1.6 Grinding dust is a waste product asbestos technical products 0.6-1.6 Water Rest

RF patent for the invention No. 2365554, MKI: C04B 28/04, date publ. 08/27/2009.

Also known is the patent “Cement of low water demand and a method for its preparation” containing Portland cement, a mineral filler in the form of a siliceous material and an organic water-lowering reagent, characterized in that in addition to the mineral filler a carbonate-containing material with a calcium carbonate fraction of at least 60% is taken, when the ratio of siliceous material and carbonate-containing material 5: 95-95: 5, while all components are taken in the following ratio, wt.%:

Portland cement 50-70 Carbonate and siliceous materials 30-50

Organic water-reducing reagent 0.3-3.0% by weight of cement low water demand

RF patent No. 2373163 MKI: C04B 7/00, C04B 7/52 date publ. 11/20/2009.

The closest analogue to the claimed invention is a “Raw mix for high-strength concrete”, including Portland cement, crushed stone, quartz sand, microsilica or fine quartz, a superplasticizer based on polycarboxylate ether and water, characterized in that it contains granite crushed stone as a superplasticizer the basis of polycarboxylate ether - Glenium 51 or Glenium ACE 30 and additionally PASh - sodium adipates and calcium formate in the following ratio of components, kg / m ³ concrete:

Portland cement 350-650 Granite crushed stone 900-1200 Quartz sand 600-800 Silica fume or finely ground quartz 7-130 Water 110-190

The specified superplasticizer 0.10-3.0 wt.% From Portland cement

PASCH 0.01-0.07 wt.% From Portland cement, calcium formate 0.5-3.0 wt.% From Portland cement.

RF patent for invention №2363680 MKI: C04B 28/04, date publ. 08/10/2009

The disadvantages of the above concrete mixtures include the fact that they use superplasticizers in large dosages, which slows down the setting time of the concrete mixture. The effect of plasticization decreases after 60-90 minutes, as well as other highly mobile mixtures are subject to delamination, which creates a heterogeneity in the structures.

Polycarboxylates are a modifier that is adsorbed on the surface of cement grains and the mineral component, which leads to higher and longer plasticization. With constant stirring, the effect is not lost, but is prolonged 3-4 times. Moreover, the surface of the grains is free for access of water and the hydration reaction.

To maintain high fluidity and prevent delamination, the mixture must be of a certain viscosity, for this a mineral additive is introduced into the mixture, which also activates the hydration processes and increases the water retention capacity of the mixture.

Therefore, in the concrete mixture proposed as an invention, a polycarboxylate-based superplasticizer developed in 2012 is used.

The technical result of the invention is to improve the quality of concrete due to its fluidity and self-sealing by introducing into the concrete mix a superplasticizer based on MC-PowerFlow 2695 polycarboxylates with a certain composition of the remaining ingredients.

The achievement of this technical result is ensured by the fact that the "Concrete mixture" includes Portland cement, crushed granite, quartz sand, microfiller, a superplasticizer based on polycarboxylates and water. At the same time, fly ash from the thermal power station is additionally introduced into it, microfiller - ground limestone MP-1, and as a superplasticizer based on polycarboxylates MS-RowerFlow 2695, in the following ratio of components, wt.%:

Portland cement 8-10 Ground limestone MP-1 6-8 Fly ash TPP GOST 25818-91 3-6 Quartz sand (1.9 micron fractions) 30-40 Granite crushed stone of fraction 3-10 mm 15-18 Granite crushed stone fractions of 5-20 mm 14-16 Polycarboxylate-based superplasticizer MS-RowerFlow 2695 0.0015-0.003 Water Rest

Ground limestone MP-1 is used, respectively, according to GOST 52129-2003 - with a fineness of grinding of less than 1.25 mm.

The superplasticizer based on polycarboxylates, (MS-PowerFlow 2695) or (MC-PowerFlow 2695), TU 5745-168-51552155-2012, is an aqueous solution of polycarboxylates and must comply with GOST 24211. An optimally selected mixture of components of the concrete mixture proposed as an invention in combined with the dosage of the above superplasticizer (MS-PowerFlow 2695) in an amount of (0.0015-0.003) wt.% promotes self-compaction of concrete, which without the influence of additional compacting energy, independently under the influence of its own mass, those It is exempt from the air contained in it and completely fills the formwork space with the reinforcing frame.

In many ways, the properties of the concrete obtained on the basis of this superplasticizer coincide with those of ordinary concrete. However, with the same cement content and water-cement ratio, it has a higher compressive strength due to the denser composition of the mixture. Also, in designs due to the high mobility of the mixture, a more tight grip with the reinforcing bars occurs. This concrete has a perfectly smooth and even surface that repeats the surface of the formwork, which makes it possible to use it in structures of any shape. Increased density, the absence of large pores reduces the risk of concrete corrosion, therefore, the quality of concrete increases, its durability and the possibility of using concrete in aggressive environments increase.

A concrete example of the preparation of concrete mix.

Consumption of materials of the concrete mixture: wt.%:

Portland cement cem I 42.5 N 9 Ground limestone MP-1 GOST 52129-2003 7 Fly ash TPP GOST 25818-91 - 4,5 Sand quartz sand (particle size modulus 1.9 μR) 35 Granite crushed stone of fraction 3-10 mm 16.5 Granite crushed stone fractions of 5-20 mm fifteen Polycarboxylate-based superplasticizer MC-PowerFlow 2695 0.00225 Mixing water Rest

The above average values of the intervals of the ingredients of the concrete mixture give the optimum quality characteristics shown in the table.

Qualitative characteristics of the proposed concrete mixture are summarized in table.

Composition number Waterproof Concrete Brand Concrete brand for frost resistance Strength, MPa 7 days Strength, MPa 28 days Cone Blur, cm one W12 F300 27.6 34.5 70

To obtain the above concrete mixture, a microfiller is dosed into the mixer - ground limestone, fly ash of thermal power plants, quartz sand and granite crushed stone of both fractions together with Portland cement and mixed for 20 seconds. Then part of the mixing water and superplasticizer are introduced and mixed for another 30 seconds. Viscosity adjusting agents are added with the last portion of water. Additives should not be added directly to the dry mix; they need to be introduced with mixing water. Due to the high efficiency of polycarboxylates, it is necessary to regularly check the performance of the dispensers. During production, it is important to consider the change in the moisture content of the aggregates, the change in the particle size distribution of the aggregates and the change in the dosage sequence.

The resulting concrete mixture has the following advantages compared to well-known similar brands of concrete:

1. Low water-cement ratio (0.37-0.4) with high workability (cone spread up to 70 cm).

2. Increase the life of structures (increased density)

3. Refusal of vibration and, as a result, reduction of noise level on a building site, decrease in energy consumption.

4. Improving the quality of the surface, which does not require additional finishing, the ability to create seamless durable industrial floors.

5. The increase in the time of preservation of the mixture, the possibility of increasing the transportation of the mixture from the concrete node to the object.

The above test results indicate that the self-compacting concrete mixture according to the invention has high workability, is highly mobile, and the resulting concrete has high frost resistance and water resistance, is not inferior in strength to known concrete, while the cement consumption for preparing the mixture is significantly lower.

The difference from other self-compacting concrete is also in that the concrete mix is compared with high-quality concrete, 60 MPa and higher. In this invention, a concrete strength of 34.5 MPa was obtained. The proposed concrete mixture can be widely used in construction.

Claims (1)

Concrete mixture, including Portland cement, crushed stone, quartz sand, micro-aggregate, polycarboxylate-based superplasticizer and water, characterized in that it additionally contains fly ash of thermal power plants, as a micro-aggregate - ground limestone MP-1, and as a superplasticizer based on polycarboxylates - MS-RowerFlow 2695, in the following ratio of components, wt.%:
Portland cement 8-10 Ground limestone MP-1 6-8 Fly ash CHP 3-6 Sand quartz with particle size modulus M _k = 1.9 30-40 Granite crushed stone of fraction 3-10 mm 15-18 Granite crushed stone fractions of 5-20 mm 14-16 Polycarboxylate-based superplasticizer (MS-RowerFlow 2695) 0.0015-0.003 Water Rest