RU2298539C1 - Light cellular concrete - Google Patents

Abstract

FIELD: building materials industry; production of the building materials.

SUBSTANCE: the invention is pertaining to building materials industry; production of the building materials and may be used for manufacture of the heat-insulation constructional materials and the heat-insulation materials at manufacture of the components of the buildings and structures in the industrial and civil engineering. The technical result of the invention is production of the heat-insulation materials with the average density from 300 up to 700 kg/m³ and the strength from 0.15 MPa up to 4 MPa. The light cellular concrete including the cement-free binding, the filler, the foam former, the foam stabilizer and the water contains in the capacity of the cement-free binding, the product of the intergrinding up to the specific surface of 600-750 m²/kg mixture, (in mass%): the calcium-high-share fly ash - 60-80, the spent molding sand of the foundry subjected to the magnetic treatment for separation of the cinder patches with the silica content above 90 % - 10-30 and the high-aluminous product with the contents of the alumina oxide above 80 % - the waste of abrasive production -5-10, and as the filler - the acidic ash of the dry selection produced after burning of the black coal, as the foam former is used "ПБ-2000" foam former, as the foam stabilizer they use the liquid sodium glass, and additionally - the super-plasticizer С-3. At that the indicated binding and the filler are previously subjected to the joint mechanical-chemical activation by the rod mill at the following components ratio (in mass %): the indicated cement-free binding - 28.4-32.1, the indicated acidic ash - 28.4-32,1, the super-plasticizer С-3 - 0.17-0.19, the liquid sodium glass - 0.16-0.2, the "ПБ-2000" foam former - 0.16-0.2, water - 35.29-42.63.

EFFECT: the invention ensures production of the heat-insulation materials with the average density from 300 up to 700 kg/m³ and the strength from near to zero MPa up to 4 MPa.

1 ex, 2 tbl

Description

The invention relates to the field of building materials, namely, thermal insulation materials from industrial wastes.

Lightweight concrete is known [RF patent No. 2140890, application. 05/14/1996, class С04В 38/02], including coal ash, high-calcium ash, gypsum, lime, aluminum powder, characterized in that the waste products of mineral wool production are used as a binder, in the following ratio of components, wt.%:

coal ash 33,3-40 high calcium ash 10-17 lime 8-12 gypsum 1-3 kings 6.3-11.3 aluminum powder 0.07-0.09 water rest

The disadvantages of the known concrete is the use of natural resources (lime), and as a gas-forming additive - expensive aluminum powder and the technologically difficult production of aerated concrete (uncontrolled process of expansion of aerated concrete).

The closest of the analogues is foam concrete [RF patent No. 2228314, application. 08/06/2002, class С04В 38/10 and С04В 28/26], which includes liquid sodium glass, a silica component, a foaming agent, a hardener - sodium silicofluoride and water, contains liquid silica glass with silica module from 2 to 4 and a density of 1.35-1.45 g / cm ³ , as a silica component - silica fume, as a foaming agent - foaming agent "Morpen" and additionally fly ash in the following ratio of components, wt.%:

specified liquid glass 63.41-69.04 silica fume 19.02-20.71 foaming agent "Morpen" 0.04-0.27 sodium silicofluoride 6.34-6.90 fly ash 1.90-2.07 water 1.24-9.06

The disadvantages of this foam concrete is the use of liquid glass in large quantities, which leads to a significant increase in the cost of foam concrete, the use of a carcinogenic component (sodium silicofluoride), which adversely affects the human body.

The objective of the invention is the creation of lightweight cementless cellular concrete based on components that have undergone mechanochemical activation, which helps to stabilize the structure of concrete and increases its strength, as well as solving the problems of using production waste (in this case, TPP).

The essence of the invention lies in the fact that lightweight cellular concrete contains: cementless binder (co-grinding product to a specific surface of 600-750 m ² / kg of mixture, wt.%: High-calcium fly ash 60-80, spent molding sand of the foundry, which has passed magnetic processing for the separation of the cakes, with silica content above 90%, 10-30 and a high alumina product with alumina content above 80% - abrasive waste 5-10 [RF patent No. 2196749, claimed 05.17.2000, class C04B 7/28] ), filler - acid ash of dry selection from burning coal (introduced as a silica-alumina component), as a foaming agent - a foaming agent based on anionic surfactants such as PB-2000, as well as an additive to reduce the water demand of the mixture in the form of C-3 superplasticizer and liquid sodium glass, as foam stabilizer, in the following ratio, wt.%:

specified cementless binder 28.4-32.1 specified acidic ash 28.4-32.1 superplasticizer C-3 0.17-0.19 liquid sodium glass 0.16-0.2 foaming agent "PB-2000" 0.16-0.2 water 35.29-42.63

The introduction of dry selection as a filler of acid ash from the combustion of coal provides the binding of free calcium oxide in a cementless binder, acting as a pozzolanic component. The chemical composition of this ash is dominated by SiO ₂ - 58.72% and Al ₂ O ₃ - 25.48%.

Compared to aerated concrete, the production scheme is simplified, and in the second case, the carcinogenic component is eliminated, which ensures the environmental cleanliness of the production of the resulting material. The proposed composition provides a solution to environmental problems through the disposal of industrial waste and the rational use of natural resources.

Pre-binder and filler are subjected to joint mechanochemical activation in a core mill, which leads to an increase in the reactivity of the constituents and facilitates subsequent porization in a turbulent mixer; according to the experimental results, a strength increase of 30% is noted. The processing of binder and filler in a core mill is effectively carried out within 5-7 minutes, which gives a mixture with a specific surface area of 650-700 m / kg at the output.

The preparation of the mixture is effectively carried out in a turbulent mixer, which gives a uniform distribution of pores of the same size over the volume of concrete. The optimal time of porosity is 5-6 minutes, a decrease in the duration of porosity does not provide the necessary degree of porosity of lightweight concrete, and an increase does not give a tangible effect and increases energy costs.

Initially, water, C-3 additive is supplied to the turbulent mixer, then powdered materials are poured, and then PB-2000 and liquid sodium glass are added.

Changing the W / T ratio allows you to get concrete with different average density and with different strengths (see table 1).

Example. To prepare lightweight concrete, a joint grinding of the binder and filler in a core mill was preliminarily carried out. Due to this, during the grinding process, mechanochemical activation of the components occurs. Then, the resulting mixture, together with the PB-2000 blowing agent, C-3 superplasticizer, liquid sodium glass and water, is mixed in a turbulent mixer.

Table 1 Test results No. The material composition of concrete, % by weight Mass g Compressive strength, MPa astringent * fly ash C-3 PB-2000 liquid
glass water ow dry one 32.1 32.1 0.19 0.16 0.16 35.29 850 700 3.9 2 31.1 31.1 0.19 0.16 0.16 37.29 770 640 2.2 3 30.1 30.1 0.18 0.18 0.18 39.26 690 560 1.8 four 29.3 29.3 0.18 0.18 0.18 40.86 530 400 0.6 5 28,4 28,4 0.17 0.2 0.2 42.63 390 290 0.15 table 2 * The material composition of the binder,% by weight No. high calcium molding fly ash Foundry sand high alumina product The specific surface of the binder, m ² / kg one 70 25 5 720 2 60 thirty 10 715 3 75 fifteen 10 718 four 80 fifteen 5 725 5 80 13 7 717

Claims (1)

Lightweight cellular concrete, including a cementless binder, filler, foaming agent, foam stabilizer and water, characterized in that it contains as a cementless binder a joint grinding product to a specific surface of 600-750 m ² / kg of mixture, wt.%: High-calcium fly ash 60-80, waste foundry foundry sand that has undergone magnetic processing to separate the cores, with silica contents above 90% 10-30 and a high alumina product with alumina above 80% - abrasive waste 5-10, and in as a filler - dry ash from coal burning, as a foaming agent - PB-2000 foaming agent, as a stabilizer of foam - liquid sodium glass, and additionally - S-3 superplasticizer, while these binder and filler are previously subjected to joint mechanochemical activation in a core mill in the following ratio of components, wt.%: The specified cementless binder 28.4-32.1 Specified Sour Ash 28.4-32.1 Superplasticizer S-3 0.17-0.19 Liquid sodium glass 0.16-0.2 Frother "PB-2000" 0.16-0.2