RU2502709C2 - Light fibre-reinforced concrete - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: light fibre-reinforced concrete is prepared from a mixture containing, vol. %: portland cement 10.0 - 22.0, granular foamed glass with particle size of 0.1 - 5 mm 40.0 - 70.0, packed or unpacked microsilica 0.5 - 3.0, generation 4 superplasticiser 0.1 - 0.3% of the weight of the binder, fibre 0.5 - 4.0 g per litre of the ready mixture, water - the balance. The light fibre-reinforced concrete is prepared from a mixture which further contains secondary filler - microcalcite with particle size of 5-100 mcm or dolomite powder or sieved sea sand. The light fibre-reinforced concrete is prepared from a mixture wherein the generation 4 superplasticiser used is polycarboxylate ether Sika Viscocrete 105P.

EFFECT: obtaining articles with a smooth front surface and low heat conductivity.

3 cl, 6 tbl

Description

The invention relates to the production of building materials and products, in particular to light concrete for insulation of floors and facades of buildings and structures, as well as the manufacture of decorative products used for decoration (decoration) of facades and interiors of buildings.

Known raw mix for the production of lightweight refractory fiber concrete, including aluminum powder, phosphoric acid 60% concentration, alumina slag, sulphate slurry, vermiculite, fiber fibers from the wire "Chromel T" in the following ratio, wt.%: Aluminum powder - 3-4 , the specified phosphoric acid is 24-26, alumina slag is 32.5-34.5, sulphate sludge is 13-15, vermiculite fractions 0-5 mm are 18-26, fiber fibers from the wire "Chromel T" with a diameter of 0.5 mm, 30 mm long - 1.5-2.5 (RF patent No. 2361847). After hardening, this raw material mixture can be used in constructions of heat engineering structures, which in addition to compressing experience significant tensile stresses.

Lightweight concrete is known, including, wt.%: Cement - 25.4-30.9, fly ash - 6.2-13.1, microsphere - 35.3-41.1, water - the rest (RF patent No. 2154619 ) This lightweight concrete has a relatively low strength and density.

Known lightweight concrete, including cement, hollow microspheres, water, siliceous opal-cristobalite rock - flask in the following ratio of components, wt.%; cement - 24.9-29.3, said flask - 11.8-20.2, these microspheres - 29.8-35.1, water - the rest (RF patent No. 2289557). The introduction of a flask, sedimentary rock of biochemical genesis instead of fly ash allows to increase the density and strength while maintaining the thermal conductivity of concrete.

Known lightweight fiber concrete made from a mixture comprising Portland cement, microspheres, a plasticizing additive, a stabilizing additive - silica fume, fiber and water (RF patent No. 2036886 - prototype). However, the prototype has a number of significant drawbacks that are eliminated by the claimed combination of essential features: the filler used in it (filler options) has a significantly higher density than the granular foam glass used by the applicant, which allows us to obtain concrete with fairly high densities, although they belong to class according to GOST lungs; judging by the information given in the examples, a decrease in density is achieved by changing the water-cement ratio, in other words by increasing the water content in the concrete mixture, which in turn leads to an increase in the porosity of the final product, which under certain operating conditions can give low frost resistance, which will limit the scope application of the material.

The material we claimed has a low density due to the filler having a closed porous structure that does not absorb moisture, which in turn provides high frost resistance of the final product; concrete samples obtained by the applicant may have a rather low density (up to 560 kg per 1 m ³ ) without forced porosity or foaming.

Known lightweight fiber-reinforced concrete, when used for the manufacture of decorative products used to decorate facades and interiors of buildings, do not provide a smooth front surface of parts with a minimum of sinks.

The objective of the invention is the creation of lightweight fiber concrete for the manufacture of decorative products used to decorate facades and interiors of buildings, having a cost comparable to conventional fiber concrete (based on the consumption of the finished mixture per unit of production), which has short production times, ease of installation, good plastic properties and provides smooth front surface of decorative products. In addition, the objective of the invention is the creation of a material with low thermal conductivity, which allows it to be used when conducting work on the insulation of facades of buildings and structures, both in the form of a finished mixture and in the form of finished products (panels, blocks).

According to the invention, lightweight fiber concrete prepared from a mixture including Portland cement as a binder, microspheres, a plasticizing additive, a stabilizing additive - silica fume, fiber and water, granular foam glass with a particle size of 0.1-5 mm is used as microspheres, as a plasticizing additive - 4 generation superplasticizer, as silica fume - silica fume in a compacted or non-compacted form, with the following ratio of components, vol.%: Portland cement 10.0-22.0, granular foam glass 40.0-70.0, silica fume in a compacted or uncompressed form 0.5-3.0, superplasticizer 4 generations 0.1-0.3% by weight of a binder, fiber 0.5-4.0 g per 1 liter the finished mixture, water - the rest.

Lightweight fiber-reinforced concrete prepared from a mixture that may additionally contain a secondary filler - microcalcite fractions from 5 to 100 microns, or dolomite flour, or seeded sea sand.

Lightweight fiber-reinforced concrete prepared from a mixture in which Sika Viscocrete 105P polycarboxylate ester is used as a 4-generation superplasticizer.

The applicant has not identified sources containing information about technical solutions, the totality of the signs of which coincide with the totality of the distinguishing features of the claimed invention.

The technical result achieved by the implementation of the distinguishing features of the invention is that the claimed composition through the use of microspheres, for example, foam glass, allows to obtain an easy-to-use, based on all the known cementitious (Portland cement) lightweight, but sufficiently strong fiber-reinforced concrete, which does not require special engineering and technical preparation of the building, which allows you to mount decorative elements made on its basis even on the walls of ordinary and country houses made of timber or foam concrete, or on ar th e insulation. The claimed lightweight fiber-reinforced concrete has a cost comparable to conventional fiber-reinforced concrete, has short lead times and ease of installation; it has good plastic and heat-insulating properties that allow it to be used for insulation of ceilings and building facades both by pouring, or by applying directly to the place, or in the form of finished products (block panels). It has fire resistance and low water absorption, which allows it to be used for the manufacture of any decor elements used both on the facades of buildings and in rooms with high humidity.

The claimed lightweight concrete is prepared as follows:

The ready-mixed dry mixture is poured into the container used for concrete preparation, then water is added at the rate of 10-11 liters per 25 kg of dry mixture. The solution is mixed with a mixer at low speeds. The mixture is mixed until a homogeneous mass. Then the mixture settles for 5 minutes to saturate the porous surface of the filler with moisture, after which it is re-mixed and poured into the mold. The exact settling time is determined by the volume of the solution prepared at one time.

The density of the mortar mixture is 0.9 kg / m ³ . The form is opened in 10-12 hours.

High performance characteristics of the claimed concrete are confirmed by the study of specific examples of its implementation.

The mixture for the preparation of the studied concrete samples was made using the following components manufactured by the industry:

- Portland cement without mineral additives of the 1st grade grade 500 (ПЦБ-1-500-ДО) (GOST 965-89, European standard EN 197-1: 2000 СЕМ I 52.5N). Production of Shchurovsky Cement OJSC;

- Granular foam glass with a size of fractions of 0.1-5 mm (TU 5914-001-15068529-2006), is a product of foaming of crushed silicate glass, chemical composition: Na ₂ O - 12.9%, CaO - 11.6%, SiO ₂ - 75.5% ;

- Condensed compacted silica fume, according to TU 5743-048-02495332-96, is a very small spherical particles of amorphous silica with an average specific surface area of about 20 square meters. m / g The chemical composition of silica fume grade MKU-85. %:

SiO ₂ p.p.p. H ₂ O Na ₂ O K ₂ O Cao SiO 91.1 2.1 0.18 1.32 2 0.35 0.68

- Spatial reinforcing additive.

Polypropylene fiber (TU 5743-001-33181465-2006)

Fiber length 6, 12, 19 mm, fiber diameter up to 12 microns, sectional shape - round;

- Plasticizer Sika Viscocrete 105P - modified polycarboxylate, white powder. Designed for the production of compositions for mortars and dry mixes from concrete. Sika Viscocrete - 105P helps to reduce excessive water, has excellent fluidity with optimal adhesion time and the highest self-compact behavior. The above applications have a positive effect on the properties of high water reduction, excellent fluidity, combined with good early hardening. Information provided by the supplier of this product to the Russian market LLC ETC (www.utsrus.com);

- Dolomite flour. Limestone powder GOST 14050-93;

- Microcalcite fractions from 5 to 100 microns: fractionated ground marble. TU 5716-001-12574404-2006;

- Seeded sea sand: natural fractionated sand according to GOST 8736-93. fractions 0-0.63 and 0.63-2.5 mm.

The possibility of industrial application of the claimed technical solution is confirmed by the known and described in the application means and methods by which it is possible to carry out the invention in the form described in the claims.

Using the claimed solution in comparison with all known means of a similar purpose provides the manufacture of decorative elements intended for both internal and external decoration of buildings and structures (columns, pilasters, rustics, cornices, window and doorway frames, decorative panels); carrying out restoration work, especially in cases where an excessive load of the object is undesirable; decorating the insulated facades of modern buildings with the installation of decor elements without creating additional supporting structures, as well as the insulation of buildings and structures.

For experimental verification of the claimed composition were made standard samples with different ratios of the above components.

Lightweight fiber-reinforced concrete reference (sample made in August 2011) Component Name About.% Cement PTsB-1-500 DO 22.0 Granular foam glass with a fraction size of 0.1-5 mm 55.0 Silica fume MKU-85 2.0 Microcalcite fractions from 5 to 100 microns 11.0 Polypropylene fiber, 12 mm fiber length 0.5 g per 1 liter of the finished mixture Sika ViscoCrete 105P superplasticizer 0.1% by weight of binder Water 10

Tests of samples of the claimed lightweight fiber concrete, conducted by the Testing Center "SPbGASU" in September 2011, showed the following.

According to the bulk density, the declared fiber-reinforced concrete has a density of 850 kg / m ³ to 1000 kg / m ³ and belongs to the light class.

Expanded density from 500 to 1800 kg / m ³ has expanded clay concrete, foam concrete, aerated concrete, wood concrete, vermiculite, perlite concrete.

Frost resistance - F200, which means the number of freeze-thaw cycles that declared concrete can withstand.

The average compressive strength is 12.2 MPa.

For workability, according to GOST 7473-94 “Concrete mixtures. Technical conditions ”, the claimed fiber-reinforced concrete belongs to the class of mobile (rigidity less than 4 seconds, divided by draft of the cone).

According to the content of binder and aggregates, concrete is marketable (with a ratio of aggregates and binder according to a standard formulation).

By the degree of readiness: in the conditions of production, the concrete mix is produced in a ready-to-use form, and for work at remote sites the concrete mix is made in dry form (Clause 3.1. GOST 7473-94 “Concrete mixtures. Technical conditions”).

To create colored concrete, white cement of the PTs-500 D0 brand is used, which makes it possible to obtain a light finished concrete mixture most suitable for introducing tinting additives.

Lightweight fiber-reinforced concrete structural and heat-insulating (sample made April 15, 2013) Component Name About.% Cement PTsB-1-500 DO 10.0 Granular foam glass with a fraction size of 0.1-5 mm 63.0 Silica fume MK-85 1,0 Seeded Sea Sand 15.0 Polypropylene fiber, 12 mm fiber length 1 g per 1 liter of the finished mixture Sika ViscoCrete 105P superplasticizer 0.25% by weight of binder Water eleven

Lightweight fiber-reinforced concrete structural (sample made April 16, 2013) Component Name About.% Cement PTsB-1-500 DO 22.0 Granular foam glass with a fraction size of 0.1-5 mm 40,0 Silica fume MKU-85 3.0 Dolomite flour 25.0 Polypropylene fiber, 12 mm fiber length 4 g per 1 liter of the finished mixture Sika ViscoCrete 105P superplasticizer 0.3% by weight of binder Water 10

Lightweight fiber-reinforced concrete architectural (sample made April 17, 2013) Component Name About.% Cement PTsB-1-500 DO 16,0 Granular foam glass with a fraction size of 0.1-5 mm 70.0 Silica fume MK-85 0.5 Polypropylene fiber, 12 mm fiber length 0.5 g per 1 liter of the finished mixture Sika ViscoCrete 105P superplasticizer 0.3% by weight of binder Water 13.5

Comparison of the obtained technical results in relation to the prototype

No. p / p Measured parameter Test procedure Water / cement ratios 0.51 0.22 0.47 The density in the dry state, kg / m ³ GOST 12730.1-78 776 1289 1182 The compressive strength in the dry state, MPa GOST 10180-90 3,1 13.1 8.6

Samples were made as follows:

The components were pre-mixed in a dry state (Portland cement, granular foam glass, silica fume, microcalcite or seeded sea sand or dolomite flour) in the appropriate proportion. For mixing, a forced-action concrete mixer of the SKAUT-200 type was used. Mixing the dry mixture was carried out for 1 minute. Next, mixing water was added to the mixture and they were mixed together for 2 minutes. Then, molding and vibration compaction of the mixture in the mold were carried out using a vibrating table for 30 seconds.

According to the results of laboratory tests, the claimed material has high consumer properties and can be used in various fields of the construction industry.

Currently, lightweight fiber-reinforced concrete is used for architectural decoration and structural and heat-insulating panels used for finishing facades of buildings. Samples of soundproof panels are being developed. The possibility of using structural lightweight fiber concrete in low-rise construction is being studied. KGIOP of St. Petersburg considers lightweight fiber-reinforced concrete to be an innovative product intended for the restoration or reconstruction of architectural monuments.

Claims (3)

1. Lightweight fiber concrete prepared from a mixture including Portland cement as a binder, microspheres, a plasticizing additive, a stabilizing additive - silica fume, fiber and water, characterized in that granular foam glass with a particle size of 0.1-5 mm is used as microspheres as a plasticizing additive, a 4-generation superplasticizer, as silica fume silica fume in a compacted or non-compacted form in the following ratio of components, vol.%:
Portland cement 10.0-22.0 granulated foam glass 40.0-70.0 silica fume in compacted or uncompressed form 0.5-3.0 4 generation superplasticizer 0.1-0.3% by weight of the binder fiberglass 0.5-4.0 g per 1 liter ready mix water rest 2. Light fiber concrete according to claim 1, characterized in that the mixture further comprises a secondary filler, which is used microcalcite fractions from 5 to 100 microns, or dolomite flour, or seeded sea sand. 3. Lightweight fiber-reinforced concrete according to claim 1, characterized in that Sika Viscocrete 105P polycarboxylate ether is used as a 4th generation superplasticizer.