RU2561121C2 - Crude mixture for making light concrete and method of making light concrete from crude mixture - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: group of inventions relates to construction materials and specifically to a construction mixture and a method of making heat-insulated light concrete from said mixture, and can be used in making light building structures for various purposes. The crude mixture for making light concrete contains, wt %: cement-containing binder 8.0-10.0 and ferromagnesium slag with particle size of 100 mcm 25.0-29.0, a natural mineral additive - metakaolin 8.0-10.0, a chemical additive catalyst - magnesium sulphate 8.0-10.0 and a plasticiser - lignosulphonate 0.05, a porous aggregate in the form of granular foamed glass 17.0-21.0, a foaming agent PB-2000 0.25, water - the balance. The method of making light concrete from said crude mixture includes premixing the binder component, active mineral additive - metakaolin, chemical additive, foaming agent solution and water, feeding the obtained mixture and porous aggregate into a vessel with an auger rotating at a rate of 100-150 rpm to uniformly force the porous aggregate into the concrete mixture, placing the hydrated mass into moulds and placing said moulds on a vibrating table, performing vibration for 3.0-5.0 s, holding for 30 min until stripping strength is achieved, followed by stripping and transporting the finished light concrete.

EFFECT: improved thermal, strength and operational characteristics of the light concrete.

2 cl, 1 tbl

Description

The invention relates to building materials, namely to a building mixture and a method for producing heat-insulating lightweight concrete from it, and may find application in the manufacture of lightweight building structures for various purposes.

A known raw material mixture for the manufacture of lightweight concrete, including finely ground glass, diatomite and semi-aqueous calcium sulfate, an aqueous solution of Belnor-1om foaming agent, thermolitic gravel as a porous aggregate, and 10% aqueous solution of caustic soda as a mixing liquid, are known as binders.

A raw mixture of these components is obtained by separately preparing a composition based on ground components: finely ground glass breakage, finely divided diatomite, semi-aqueous calcium sulfate with the addition of a 10% aqueous solution of caustic soda, separate preparation and introduction of a 6% aqueous solution of caustic foaming agent and thermolite gravel during a continuous process mixing until completely enveloped with an aqueous dispersion of the mineral binder surface of the aggregate (see IPC SB04 / 10/10 description of the invention to the patent Russian Federation 2422411, publ. 27.06.2011).

A method of manufacturing lightweight concrete from this composition involves laying it in metal molds, holding it for 12 hours before gaining formwork strength, holding molded products for 24 hours, then curing them out of the molds by heat-moisture treatment.

The disadvantage of this mixture and the method of manufacturing lightweight concrete from it is the increased duration of concrete hardening.

Closest to the claimed technical solution is a raw material mixture for the manufacture of lightweight concrete, including cement, fly ash of a thermal power plant, a Belnor-1om foaming agent solution, liquid sodium glass as a chemical additive, and granular foam glass as a porous aggregate (see IPC С04В 38 / 00, description of the invention to the patent No. 2255920 of the Russian Federation, publ. 10.07.2005).

The disadvantages of the known raw mix are:

- high consumption of cement;

- increasing the consumption rate of the porous aggregate with a fraction of 5-40 mm, due to its abrasion during mixing of the mixture.

A method of manufacturing lightweight concrete from this mixture includes preparing a concrete mixture from cement, fly ash of thermal power plants, liquid sodium glass, the subsequent introduction of technical, pre-prepared foam, mixing until a homogeneous foam concrete mixture is obtained, into which porous aggregate is then gradually introduced with continuous mixing mixtures for 0.5-2.5 minutes, laying the mixture in metal molds, holding for 12 hours until the formwork strength is set, subsequent heat treatment of the fabricated concrete for 12 hours at a temperature of 80-85 ° C.

The disadvantages of the method of manufacturing lightweight concrete from this raw material mixture are:

- 100% water use at the stage of preparation of a mixture of cement, fly ash of a thermal power plant, a foaming agent and a chemical additive leads to an increase in water absorption of concrete and, as a result, to a deterioration in its heat-insulating and strength characteristics during water saturation;

- deterioration in strength characteristics due to an increase in intergranular voids with stirring;

- a long period of hardening of concrete.

The technical result of the claimed invention is to improve its heat engineering, strength and operational characteristics.

The essence of the technical solution lies in the fact that in the raw mixture for the manufacture of lightweight concrete, including a binder containing cement, a foaming agent, a chemical additive, a porous aggregate in the form of granular foam glass and water, the binder additionally contains 100 μm ferromagnesium slag, and the raw mixture contains as a foaming agent - PB-2000 foaming agent, and as a chemical additive, the catalyst is magnesium sulfate and a plasticizer is lignosulfonate, and the mixture additionally contains a mineral additive at . The same origin - metakaolin, the following component ratio, wt%:

cement 8.0-10.0 ferromagnesium slag 25.0-29.0 metakaolin 8.0-10.0 magnesium sulfate 8.0-10.0 lignosulfonate 0.05 PB-2000 foaming agent 0.25 granulated foam glass 17.0-21.0 water rest

To do this, in the method of manufacturing lightweight concrete from a raw mix, characterized by pre-mixing the binder component, a foaming agent solution, a chemical additive and water, followed by the introduction of porous aggregate with continuous stirring, laying the closed mass into molds and holding it to a set of stripping strength, after which stripping is carried out and transportation of the finished lightweight concrete, the active mineral additive metakaolin is introduced with preliminary stirring, then the resulting mixture and the porous aggregate is fed into a container with a screw rotating at a speed of 100-150 rpm, through which the porous aggregate is uniformly pressed into the concrete mixture and after laying the closed mixture in the molds, they are fed to a vibrating table, subjected to vibration for 3.0-5, 0 seconds, and exposure to a set of stripping strength is carried out for 30 minutes.

The introduction of metakaolin, an active mineral additive, which is a kind of aggregate, into the mixture makes it possible to reduce the amount of binder — cement and ferromagnesium slag with a grinding fraction of 100 microns — while maintaining the strength of concrete.

The introduction of a mixture of a catalyst — magnesium sulfate and a plasticizer — lignosulfonate makes it possible to accelerate the solidification of concrete and improve the quality of mixing of the concrete mixture.

In the closest analogue, when mixing the foam concrete mixture and porous aggregate, the latter is abraded, which leads to an increase in intergranular voids and consumption rates of aggregate.

In the claimed method of manufacturing lightweight concrete, the porous aggregate - granular foam glass and the concrete mixture obtained in the preliminary mixing stage are fed simultaneously into a container with a rotating screw, which allows the process of uniformly pressing the porous aggregate into the concrete mixture and to prevent the formation of intergranular voids.

Processing molds with concrete mixture on a vibrating table allows to remove trapped air from the samples, which, together with the process of pressing a porous aggregate, allows to obtain lightweight concrete with improved thermal and strength characteristics.

The following components are used to produce the raw material mixture: cement GOST GOST 10178-85, granular ferromagnesium slag, pozzolan (metakaolin) TU 572901-001-657-671-84-2010, magnesium sulfate catalyst TU 2141-016-324-964-45- 00, lignosulfonate plasticizer TU 2455-031-462897-15-2000 or TU 2455-002-0028-1039-00, blowing agent PB 2000 TU 2481-185-057-44685-01, granular foam glass TU 5914-001-15068529-2006 , water for concrete and mortar GOST 23732-79.

A method of manufacturing lightweight concrete from the claimed raw material mixture is carried out as follows: cement, ferromagnesium slag of the grinding fraction 100 μm, metakaolin, catalyst - magnesium sulfate, plasticizer - lignosulfonate, PB-2000 foaming agent and water are mixed into the forced mixing mixer according to the recipe, mix for 10 -20 seconds during which the foaming of the raw material mixture occurs. Then the mixture and the porous aggregate are fed into another tank of the passage type with a rotating screw with a rotation speed of 100-150 rpm, by which uniformly pressing the porous aggregate into the concrete mixture. The obtained shut-off mixture is placed in molds and fed to a vibrating table, where they are subjected to vibration for 3-5 seconds, after which the molds with concrete are held for 30 minutes until the stripping strength is set, followed by stripping and transportation of the finished lightweight concrete. The table shows the composition of the raw mix:

The indicated ranges of mixing mixtures, vibration processing of molds and holding to formwork strength are optimal for the inventive raw mix and method of manufacturing lightweight concrete from it.

Testing of samples of the raw mix and the method of manufacturing lightweight concrete according to the claimed invention was carried out in accordance with the requirements of GOST and test methods for building mixtures and materials.

Tests have shown that lightweight concrete made from the inventive raw material mixture has the following characteristics:

- density from 200 to 500 kg / m ³ ;

- frost resistance from 0.75 to 2.5;

- tensile strength class B 12.5 for lightweight concrete on porous aggregates;

- the coefficient of thermal conductivity in the range from 0.065 to 0.12 W / m, which meets the requirements of GOST and SNiP 11-3-79.

Thus, in contrast to the known raw mixes for lightweight concrete and methods for its manufacture, the inventive mixture and method allows to obtain environmentally friendly building material without any chemical additives, with high strength properties and thermal insulation characteristics, cheap to manufacture and a wide range of applications in civil and industrial construction.

Claims (2)

1. The raw material mixture for the manufacture of lightweight concrete, including a binder containing cement, a foaming agent, a chemical additive, a porous aggregate in the form of granular foam glass and water, characterized in that the binder additionally contains ferromagnesium slag fractions of 100 microns, and the raw mixture contains as a foaming agent - PB-2000 foaming agent, and as a chemical additive, the catalyst is magnesium sulfate and the plasticizer is lignosulfonate, and the mixture additionally contains a mineral additive of natural origin - metacao . In, with the following ratio of components, wt%:
cement 8.0-10.0 ferromagnesium slag 25.0-29.0 metakaolin 8.0-10.0 magnesium sulfate 8.0-10.0 lignosulfonate 0.05 PB-2000 foaming agent 0.25 granulated foam glass 17.0-21.0 water rest 2. A method of manufacturing lightweight concrete from a raw mix according to claim 1, characterized by preliminary mixing of a binder component, a foaming agent solution, a chemical additive and water, the subsequent introduction of porous aggregate with continuous stirring, laying the closed mass into molds and holding it to a set of stripping strength, after which carry out the stripping and transportation of the finished lightweight concrete, the active mineral additive metakaolin is introduced with preliminary stirring, then the resulting mixture and porous the second aggregate is fed into a container with a screw rotating at a speed of 100-150 rpm, through which the porous aggregate is evenly pressed into the concrete mixture and after laying the closed mixture in molds, they are fed to a vibrating table, subjected to vibration for 3.0-5.0 seconds, and exposure to a set of stripping strength is carried out for 30 minutes.