RU1791418C - Stock for producing cellular concrete - Google Patents

Abstract

The invention relates to the building materials industry and can be used for the manufacture of four-concrete thermal insulation materials. As a phosphate binder, the mixture contains a by-product of physicochemical treatment of wastewater from galvanic shops containing 50-85% phosphoric acid. The raw mix for the manufacture of cellular concrete contains, wt.%: Phosphate binder 20-50%, sulfuric acid 9.5-17%, chromium oxide 0.5-3%, fly ash the rest. A method of preparing a mixture. Before the mixture was prepared, the entrainment zone was dried at room temperature to an air-dry state. Grinding of materials is carried out in a ball mill. The specific surface of fly ash was up to 7000 cm / g. The components were mixed for 10 minutes. The compressive strength of the samples is 5.5–7.2 MPa, and frost resistance is 30–40 cycles. 3 tab.

Description

The invention relates to the building materials industry and can be used for the manufacture of concrete concrete insulating materials enclosing building structures, for example, insulating coatings of pipelines, as well as self-supporting wall panels, small wall blocks, and the like.

Currently, a large number of compositions of raw materials for the manufacture of aerated concrete are known, the main ingredients of which are silica sand, lime-siliceous binder, the blowing agent is aluminum powder and water, which is used as a solvent.

The main disadvantages of such a mixture are the low strength and frost resistance of products based on them.

Of the known raw materials for the manufacture of cellular concrete, the closest in technical essence and the achieved effect is a pure concrete mixture, including the following ingredients, wt.%: Phosphate binder 35-67 Ash 30-62 Aluminum powder 0.1-; 0.2 Used engine oil 1-3 The main disadvantages of the raw material mixture are the low strength and frost resistance of cellular concrete.

The advantage of this raw mix is the expansion of the raw material base through the use of fly ash and used engine oil, and a decrease in shrinkage of products.

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The aim of the invention is to increase the strength of products, their frost resistance.

This goal is achieved by the use of an additive in the mass of sulfuric acid and chromium oxide in the following ratio of components, wt.%;

Phosphate Binder 20-50

Sulfuric acid 10-15

Chromium Oxide 0.5-3.0

Fly ash

It has been experimentally established that in the preparation of lightweight concrete using sulfuric acid and chromium oxide, average calcium phosphate is formed. In addition to medium phosphate, β-and hydrated silica is formed. Neoplasms are largely amorphized.

Such a nature of the neoplasms leads to higher strength properties of the samples.

As a binder, by-products of physico-chemical treatment of wastewater from galvanic shops with a content of 50-85% phosphoric acid are used.

The phosphate binder is a viscous liquid with a specific gravity of 1.254.

Fly ash - fine powder with a specific surface of up to 7000 cm2 / g, chemical composition of fly ash (see Table 1}.

Sulfuric acid is a viscous liquid with a specific gravity of 1.066.

Chromium oxide is a green powder with a specific surface area of 6000 cm2 / g.

In order to obtain samples of cellular concrete based on the proposed concrete mixture, eight composition mixtures were made from the presented compositions and one according to the prototype (Table 2).

The following is the phosphoric acid content of the phosphate binder in each mixture of the example:

Mixture, No. Phosphoric acid content in phosphate binder,%

130

250

360

465

580

685

770

862

940

A method of preparing a mixture.

Before preparing the fly ash mixture, it was dried at room temperature to an air-dry state.

The grinding of materials was carried out in a ball mill. The fineness of the grinding of materials was established by determining the specific surface on the PSX-2 device, as well as by sifting through standard sieves. The specific surface of fly ash is up to 7000 cm2 / g.

Conditions for the preparation of cellular concrete: dosage of fly ash, phosphate binder, additives in separate containers in predetermined proportions of components; mixing the components of the mixture for 10 minutes

From the prepared compositions, cube samples of 70 x 70 mm in size were prepared by heat treatment in a muffle furnace, at 623 K for 1 h,

The obtained samples were subjected to physical and mechanical tests for frost resistance (according to GOST 12852.4-74 Concrete, cellular. Method for determination of frost resistance); compressive strength (according to GOST 10180-78). The test results are presented in table. 3.

As can be seen from the table. 3, on the proposed compositions significantly superior in their strength and frost resistance to the samples of the prototype.

Samples Ms. 2-7 showed the best results, which confirms the proposed limits adopted in the claims.

The use of the proposed pure concrete mixture or in the manufacture of lightweight concrete allows to increase the strength of products up to 7.2 MPa and frost resistance up to 40 cycles, compared to the prototype 1.4 times, to increase the service life of construction objects.

Claims (1)

/ Claims Raw mix for the manufacture of cellular concrete, including phosphate binder, fly ash and an additive, characterized in that, in order to increase strength and frost resistance, it contains sulfuric acid and chromium oxide as an additive in the following ratio, wt.%; . Phosphate Binder 20-50 Sulfuric acid 9.5-17 Chromium Oxide 0.5-3 Fly ash Table 1 Table 3 Physico-mechanical characteristics of the samples table 2