RU2411218C1 - Raw mixture for making foamed concrete - Google Patents

Abstract

FIELD: chemistry. ^ SUBSTANCE: invention relates to production of construction materials and can be used in making articles used in building and heat insulation of residential and industrial buildings. The crude mixture for making foamed concrete contains the following, wt %: portland cement 28.0-30.0, gaize 30.0-32.0, aluminium powder 0.2-0.51, hemihydrate gypsum 0.5-1.5, sodium hydroxide 1.3-2.0, water 36.0-38.0. ^ EFFECT: obtaining foamed concrete with low density and high strength. ^ 1 ex

Description

The invention relates to the production of building materials and can be used in the manufacture of products used for the construction and thermal insulation of residential and industrial buildings and structures.

Known raw material mixture for the production of non-autoclaved aerated concrete, including cement, a siliceous component, a surfactant, a plasticizer and water. Sodium aluminate and polyamide fibers 3-5 mm long are additionally introduced into this mixture as a stabilizer in the following ratio of components, wt.%:

Cement 43-90 Siliceous component 5-45 Surfactant 1-2 Sodium Aluminate 0.75-2.5 Plasticizer 0.5-1.5 Polyamide fibers 2.75-6.0 Water 0.25-0.6

The main disadvantage of this cellular concrete mixture is that pre-synthesized sodium aluminate is introduced into the mixture as a stabilizer. An essential feature of the synthesis of sodium aluminate is that at the time of formation it is in a colloidal gel state, from which it passes into a fine crystalline state within a short time. Therefore, introducing it into the aerated concrete mixture in a pre-synthesized form does not give the expected positive effect in the formation of the microstructure and strength of the inter-pore walls of aerated concrete. In addition, during crystallization, sodium aluminate binds up to six moles of water, and therefore the pre-synthesized sodium aluminate already contains this water and does not bind it in the aerated concrete mixture when it is porous. The stabilization of this process according to the known composition is achieved through the use of a fairly scarce S-3 superplasticizer and a relatively large amount of polyamide fiber additive [RU 2226517, cl. 7 C04B 38/02, 2004].

Known raw mix for the manufacture of non-autoclaved aerated concrete, including Portland cement, a suspension of aluminum powder, milk of lime, gypsum in the form of a suspension in water in a ratio of 1: 1, silica fume, calcium chloride and mixing water in a ratio of components, wt.%:

Portland cement 51-71 Aluminum powder 0.01-0.15 Lime 0.04-0.7 Semi-aquatic gypsum 0.1-0.4 Silica fume 0.6-3.5 Calcium chloride 0.5-3 Water Rest

[RU 2209801, cl. 7 C04B 38/02, 2003]. The main disadvantage of this mixture is the following. The introduction of a lime mortar into the aerated concrete mixture does not accelerate the process of porization.

Known raw mix for the manufacture of non-autoclaved aerated concrete, including Portland cement, a suspension of aluminum powder, a suspension obtained by mixing semi-aquatic gypsum with water in a ratio of gypsum: water equal to 1:10, 30-40% sodium hydroxide solution, fiber additive and water [RU No. 2276121, 05/10/2006].

The main disadvantage of this mixture is its low strength due to the introduction of a coarse component - a fibrous additive.

The present invention is the formation of a strong structure of inter-pore walls due to the fine dispersion of all components and the chemical composition of the flasks, providing aerated concrete with low density and high strength.

In the present invention, the raw material mixture for the manufacture of aerated concrete, including Portland cement, aluminum powder, semi-aqueous gypsum, sodium hydroxide and water, additionally contains flask in the following ratio, wt.%:

Portland cement 28.0-30.0 Flask 30.0-32.0 Aluminum powder 0.2-0.51 Semi-aquatic gypsum 0.5-1.5 Sodium hydroxide 1.3-2.0 Water 36.0-38.0

Semi-aquatic gypsum is used with a particle size of 0.01-0.03 mm in diameter. The flask is used with a particle size of 0.001-0.01 mm in diameter. The chemical composition of the flasks includes silicon oxide (75-80%), aluminum oxide (18-23%), oxides of iron, lead, manganese, copper, cobalt, molybdenum, magnesium, zinc (in the amount of 2%).

Example. Mix 28 wt.% (28 g) of Portland cement, 32 wt.% (32 g) of the flask and 38 wt.% (38 g) of water. 1.3 wt.% (1.3 g) of sodium hydroxide, 0.5 wt.% (0.5 g) of semi-aqueous gypsum and 0.2 wt.% (0.2 g) of aluminum powder are added to this mixture. The mass is continuously stirred for 20 minutes and the necessary products (plates, etc.) are molded. The temperature of the mixture and molds must be maintained in the range from 30 to 40 ° C. The molded products are heated for 3.5-4 hours at 75-85 ° C, while products with a strength of up to 4.5-5.5 MPa and a density of 900 kg / m ³ are obtained, which is consistent with GOST 25485-89.

Products from aerated concrete made of this mixture in the form of blocks, plates of various sizes, can be used as heat-insulating or structural materials in the construction of various objects for domestic and industrial use.

Claims (1)

The raw material mixture for the manufacture of aerated concrete, including Portland cement, aluminum powder, semi-aquatic gypsum, sodium hydroxide and water, characterized in that it additionally contains flask in the following ratio of components, wt.%:
Portland cement 28.0-30.0 flask 30.0-32.0 aluminum powder 0.2-0.51 semi-aquatic gypsum 0.5-1.5 sodium hydroxide 1.3-2.0 water 36.0-38.0