CS227591B1 - Composition for manufacturing cellular concrete and method of preparing same - Google Patents

Description

The invention relates to aerated concrete made of _; mixtures containing silica sand, power plant! fly ash, slag, diatomaceous earth or a combination thereof as a filler, cement and / or lime as an active binder, gypsum or waste sulphate, aluminum powder or paste, growth sludge and water, and a process for its manufacture. In the production of aerated concrete, lime, cement or lime-cement binders are used whose dosage in terms of quality and quantity depends on the machinery used and the cycle time. The production mixture prepared by wet or dry grinding of raw materials, or in a combined way, is cast into molds in which the process of loosening and maturing is carried out due to the hydration of the binders. After reaching the prescribed plastic strength values for the given technology, it is possible to demold, cut and further manipulate it. In this state, however, the material exhibits low resistance to external forces, and if it is further handled before hydrothermal treatment, when the material receives the ultimate strength, the integrity of the individual de-molded pieces often occurs. Depending on the filler and binder used, volume changes in the material often occur during autoclaving.

These drawbacks are overcome by the aerated porcelain according to the invention, characterized in that it contains 1.0 to 30% by weight of lime hydrate and / or carbide lime, the percentage being based on the dry weight of the porous concrete.

'. Waste and carbide lime can be processed in all production technologies. It is advantageous to dispense ^{1 in the} form of sludge directly into the mixer or in the case of wet grinding into mills, which contributes to avoiding sedimentation of the filler, i.e. sand or fly ash sludge.

the use of waste and carbide lime not only increases the resistance of the non-autoclaved aerated concrete to external forces and mechanical damage, and reduces the susceptibility of aerated concrete to volume changes during hydrothermal treatment, but also results in lower bulk weights and reduced consumption of gaseous substances and active binder component. The processing of these limes also increases the ultimate strength of the aerated concrete, whilst the lime component is fully replaced in terms of hydrothermal reactions. In addition, the issue of the use of waste and, above all, carbide lime, which is otherwise gradually degraded in landfills, the construction and existence of which represents both economic losses and a serious environmental problem, is addressed.

The invention will be described in more detail by way of examples.

Example 1

Raw material mixtures were prepared by the technology of joint grinding of the filler and the active binder

(a) 65% quartz sand, 20% cement, 15% lime

(b) 75% power plant fly ash, 10% cement, 15% lime

(c) 85% power plant fly ash, 5% cement, 10% lime

d) 70% binder combination, 15% cement, 15% lime.

Production mixtures were prepared from these raw materials according to the following recipe of ingredients per 1 m ^{3 of the} mixture:

AND (B) C D raw material mixture (kg) 350 290 300 300 overgrowth sludge (dry matter) (kg) 100 ALIGN! 110 75 60 carbide lime (dry matter) (kg) 50 45 100 ALIGN! 45 aluminum powder (kg) 0.30 0.35 0.35 0.40 waste sulphate (dry matter) (kg) - 9 25 9 magnesium oxide (kg) 5 - - surfactants (O 0.2 0.1 0.15 0.15 water coefficient 0.60 0.65 0.65 0.70 The aerated concrete exhibited the following characteristics: AND (B) C D Density (kg / m ³ ) 550 500 550 450 compressive strength (MPa) 4.1 3.4 3.9 2.7

Example 2

With the technology of wet grinding production sludges were prepared with the following composition:

(e) 95% quartz sand, 5% waste lime hydrate; (f) 90% power plant fly ash, 10% carbide lime;

(g) 80% sand with power ash, 20% carbide lime. ¹

Production sludges were prepared from these sludges; mixtures according to the following ingredient formulas nal m ^r

mixtures: --- E F G production sludge (dry matter) (kg) 310 180 200 cement (kg) 175 70 180 quicklime (kg) - 55 - oversize sludge (dry matter) (kg) 55 50 70 waste sulphate (dry matter) (kg) - . 5 - aluminum powder (kg) 0.28 0.40 0.70 surfactants (1) - 0.20 0.10 water coefficient 0.70 0.66 0.40

The aerated concrete exhibited the following characteristics:

E F G density (kg / m ³ ) 600 400 500 compressive strength (MPa) 4.2 2.8 5.1

Example 3

The technology of dry grinding of raw material mixture prepared a mixture with the following composition:

(h) 85% fly ash, 10% lime, 5% gypsum by means of the wet milling technology of the product sludge mixture containing __ _________

(i) 62% silica sand, 30% carbide lime and 8% waste sulphate.

With the technology without grinding raw materials, the mixture listed in the following overview under the designation J was prepared.

Production mixtures were prepared from these mixtures according to the following formulas of composition per 1 m ³ : i

H AND 3 production mixture (kg) 350 - - production sludge (dry matter) (kg) - 175 - cement (kg) - 100 ALIGN! 25 quicklime (kg) - - 50 fly ash (kg) - 150 280 carbide lime (kg) 75 - 50 oversize sludge (dry matter) (kg) 75 - 75 waste sulphate (dry matter) (kg) - - 20 May aluminum powder (kg) 0.35 0.35 0.35 surfactants (1) 0.15 0.15 0.15 water coefficient 0.65 0.65 0.65

The concrete produced exhibited the following characteristics:

density (kg / m ³ ) 550 550 550 compressive strength (MPa) 3.5 3.3 3.1

SUBJECT OF THE INVENTION

Claims (3)

1. A aerated concrete composition comprising: quartz sand, power plant fly ash, slag, quartz or a combination thereof as filler, cement and / or lime as active binder, additives and water in an amount corresponding to a water factor of 0.35 to 0 8, characterized in that it contains 1.0 to 30% by weight of lime hydrate and / or carbide lime, the percentage being based on the dry weight of the aerated concrete. 2. A process according to claim 1, characterized in that the lime hydrate and / or carbide lime is added to the production mixture in a mixture of the effluent. 3. A process for the preparation of a mixture according to claim 1 by the wet grinding technology, characterized in that lime hydrate and / or carbide lime is also added to the process sludge.