RU2403232C1 - Autoclave foam concrete mixture - Google Patents

Abstract

FIELD: chemistry. ^ SUBSTANCE: invention relates to construction materials and specifically to autoclave hardened cellular concrete. The autoclave foam concrete mixture contains the following in wt %: portland cement 17.52-19.90; lime 6.9-7.18; sand 45.17-47.05; foaming additive 0.23-0.24; water 19.46-19.61; waste condensate from autoclave treatment of cut foam concrete - air brick 8.34-8.40. ^ EFFECT: faster development of cutting strength and reduced dry shrinkage. ^ 1 tbl, 1 ex

Description

The invention relates to the field of building materials, in particular to cellular concrete autoclaved.

A known mixture for the manufacture of foam concrete containing Portland cement, sand, lime, water and a foaming additive in the following ratio of components, wt.%: Portland cement - 12.22-14.60, sand - 41.83-42.10, lime - 20, 1-21.3, protein-based foaming additive - 0.07-0.08, water - 23.4-24.3 (Khitrov A.V. Obtaining modern autoclaved foam concrete, taking into account the nature of the introduced building foams. Author. Dis. for the competition of the senior academic candidate of technical sciences, St. Petersburg, PSUPS, 2000, p.1-29).

Closest to the claimed mixture is a mixture for the manufacture of autoclaved foam concrete, consisting of cement, sand, lime, water and a complex foaming additive in the following ratio of components, wt.%: C ₁₉ H ₂₉ COONa · 3C ₁₅ H ₂₉ COOH - 30.34- 33.67, KOH - 6.88-7.64, glue - 10.67-11.83, water - 34.11-37.86, fatty acid salt - 9.0-18, and the following ratio of mixture components for cellular foam concrete: cement - 38-42, sand - 28-30, lime - 4.2-4.6, complex foaming additive - 0.4-0.7, water - 25.4-26.7 (RF patent No. 2205814, С04B 38/10, May 6, 2002).

The disadvantages of these mixtures are the long time required to set the cutting strength of the raw concrete mass and the high value of shrinkage during drying of the foam concrete products.

The objective of the invention is the creation of a new mixture, providing autoclaved foam concrete with improved characteristics, namely with reduced terms for the set of cutting strength of the raw concrete mass and low shrinkage when drying foam concrete products.

The problem is achieved in that the mixture for autoclaved foam concrete containing Portland cement, lime, sand, water and a foam-forming additive further comprises condensate waste generated during the autoclave treatment of the cut raw foam concrete array in the following ratio of components, wt.%:

Portland cement - 17.52-19.90

lime - 6.9-7.18

sand - 45.17-47.05

foaming additive - 0.23-0.24

water - 19.46-19.61

specified waste - 8.34-8.40

EXAMPLE OF SPECIFIC PERFORMANCE

Production of autoclaved foam concrete.

1. Preparation of raw materials:

- wet grinding of sand to obtain a sand slurry density of ≈1.6 g / l with a specific particle surface of 280-300 m ² / kg;

- selection of the autoclave condensate formed during the production into metal containers for cooling to t≈20 ° C. The composition of waste condensate includes calcium ions (Ca ^2+), magnesium (Mg ^2+), iron (Fe ^2+), iron (Fe ^2+), bicarbonate (HCO ₃ ^+), ammonium (NH ₄ ^+), pH 13.

2. Dosing and loading into the mixer of raw materials:

- sand slurry with the required parameters;

- water in accordance with GOST 23732-79;

- liquid waste condensate;

- quicklime powder, with a quenching rate of up to 8 min and containing active CaO + MgO of at least 70%, “burn-out” of not more than 2%;

- Portland cement PC 400 D0 ... D20 and PC 500 D0 ... D20, with a C ₃ A content of not more than 6%.

3. Mixing the raw materials in the mixer.

4. Porization of the mixture due to the foam separately prepared from the foaming agent solution. The following can be used as a foaming agent: a protein-based foaming agent (Addiment SB 31L), which includes protein hydrolysates, density 1.09 kg / l, pH≈7 ... 7.5; a foaming agent based on derivatives of carboxylic acids (KVIN), a density of ≈1.3 kg / l, pH≈8 ... 9, as well as a foaming agent based on resin acids - glucose-roaming foaming agent (KKPO), density 1.2 kg / l, pH ≈8.5 ... 9.5 (Khitrov A.V. Obtaining modern autoclave foam concrete, taking into account the nature of the introduced building foams. Author. Diss. .9, 15).

5. Transportation with the help of a concrete distributor of foam concrete mixture to the holding chamber and its laying in the molds.

6. Exposure of foam arrays to a set of cutting strength = 0.028 MPa, (the cutting strength is determined by a plastometer, the time of setting of cutting strength by a raw concrete array is shown in the table).

7. Cutting foam arrays into products.

8. Autoclave processing of products.

9. Samples of foam concrete products after autoclaving are subjected to tests to determine shrinkage during drying according to GOST 25485, the results are presented in the table.

An analysis of the results shows that autoclaved foam concrete based on the proposed composition has a reduced set of cutting strength and low shrinkage during drying.

Accelerating the set of cutting strength by raw foam concrete mass reduces the time of the technological cycle of obtaining autoclaved foam concrete by cutting technology and thereby leads to increased productivity and reduced energy costs of production.

Claims (1)

A mixture for autoclaved foam concrete, including Portland cement, lime, sand, water and a foaming additive, characterized in that it additionally contains waste condensate generated during the autoclave treatment of the cut raw foam concrete array, in the following ratio, wt.%:
Portland cement 17.52-19.90 lime 6.9-7.18 sand 45.17-47.05 foaming additive 0.23-0.24 water 19.46-19.61 specified waste 8.34-8.40