RU2258681C1 - Raw mixture for preparing water-proofing building material - Google Patents

Abstract

FIELD: building industry and materials.

SUBSTANCE: invention relates to preparing wall constructive material based on secondary gypsum dihydrate. Raw mixture for preparing water-proofing building material comprises secondary gypsum dihydrate, slaked lime as saturated solution and microsilica as additive in the following ratio of components, wt.-%: secondary gypsum dihydrate, 70-80; microsilica, 5.5-6.5; slaked lime, 0.0135-0.019, and water, the balance.

EFFECT: improved preparing method.

1 tbl, 3 ex

Description

Technical field

The present invention relates to the field of construction, in particular to the production of wall structural material based on two-water secondary gypsum - waste from porcelain and faience production.

State of the art

Known raw material mixture for the manufacture of building material, including crushed wood, gypsum, water and an additive, and it contains ferrous sulfate and aluminum sulfate as an additive, and additionally quicklime powder, in the following ratio of components, wt.%: Wood chopped (absolutely dry ) 30-40; gypsum 30-40; ferrous sulfate 8-12; aluminum sulfate 1-2; ground quicklime 2-3; the rest is water (see patent No. 17905563, IPC: C 04 B 28/14, B.I. No. 3 - 1993).

The closest technical solution to the claimed is a raw material mixture for the preparation of building material, including wood, gypsum, an additive and water, and it contains as an additive trivalent metal sulfate and additional quicklime ground in the following ratio of components, wt.%: Crushed wood (absolutely dry) 35-40; gypsum 25-28; trivalent metal sulfate 7-8; quicklime powder, ground 10-12; the rest is water (see patent No. 1804454, IPC: C 04 B 28/14, 1990).

The disadvantage of the above technical solutions is the use of expensive components.

SUMMARY OF THE INVENTION

The basis for the creation of the invention is the task of manufacturing a building material obtained on the basis of non-calcined secondary gypsum and characterized by increased water resistance and strength.

The problem is solved by introducing an addition of silica fume to increase water resistance, using non-fired secondary gypsum to reduce the cost of material and slaked lime solution to eliminate internal corrosion. The proposed composition contains two-water secondary gypsum with the addition of silica fume and a saturated solution of lime in the following ratio of components, wt.%:

Two-water secondary gypsum 70-80

Silica fume 5.5-6.5

Slaked lime 0,0135-0,019

Water Else

Two-water secondary gypsum was taken in an amount of not less than 70% to ensure a material density of not more than 80%, to ensure the strength of the material.

With the introduction of lime less than 0.0135%, a decrease in the strength of the material is possible, and with a lime content of more than 0.019%, the volume of the solution will exceed the water demand of the mixture.

Silica fume was taken in an amount of at least 5.5% to ensure strength and water resistance. When the content of silica fume is more than 6.5%, the development of internal corrosion of the material is possible.

Information confirming the possibility of carrying out the invention

Example 1

2 kg lumpy secondary gypsum was crushed on a jaw crusher, followed by drying. After drying to a constant weight, a weigher of 1.5 kg was weighed out and loaded into a mill with grinding bodies of celpebs. Milling was carried out to a specific surface of 6400 cm ² / g. A portion of ground gypsum in an amount of 65 g was mixed in a dry state with silica fume in an amount of 5.5 g. The resulting dry mixture was closed with a saturated solution of lime, consisting of 0.0162 g of lime and water.

Samples were formed from the resulting mixture by two-stage pressing. In the first stage of pressing, the pressure was 1/3 of the full load and was maintained for one minute. In the second stage, the pressure was brought to the calculated value and maintained for three minutes.

Hardening occurred at an air humidity of at least 95% and a temperature of 20 ° C for 28 days.

Example 2

We take the following composition, g:

Two-water secondary gypsum 70 Silica fume 6 Slaked lime 0.0135 Water Rest

The production of samples is carried out according to the method described in example 1.

Example 3

We take the following composition, g:

Two-water secondary gypsum 75 Silica fume 6.5 Slaked lime 0.019 Water Rest

The production of samples is carried out according to the method described in example 1.

The results obtained are illustrated by the data given in the table.

Table No. p / p Composition, wt.% The limit of compressive strength, MPa Softening coefficient 1 Two-water secondary gypsum - 70,
17.24
0.75 silica fume - 5.5, slaked lime - 0.0135, water - the rest 2 Two-water secondary gypsum - 75,
22.6
0.99 silica fume - 6, slaked lime - 0.016, water - the rest 3 Two-water secondary gypsum - 75,
27.0
0.53 silica fume - 6.5, slaked lime - 0.019, water - the rest

Industrial applicability

Experimental laboratory tests were carried out in the laboratory of the department "Production of building products and structures" of Tver State Technical University. The following results were obtained: compressive strength of 22.6 MPa and a water resistance coefficient of 0.99, which corresponds to gypsum materials of grade G-19. In the production of this material there is a decrease in energy consumption through the use of two-water secondary gypsum.

Claims (1)

The raw material mixture to obtain a waterproof building material, including gypsum, lime and water, characterized in that it contains two-water secondary gypsum, slaked lime in the form of a saturated solution, and as an additive - silica fume, in the following ratio, wt.%: Two-water secondary gypsum 70-80 Silica fume 5.5-6.5 Slaked lime 0.0135-0.019 Water Rest