RU2645000C1 - Gypsum board panel core based on modified gypsum binding - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to building materials and can be used for the production of gypsum board products. Gypsum board core based on the modified gypsum binder includes 46.4–52.6 % by weight of construction gypsum and 33.3–34.2 % by weight of water. At that it further comprises 13–20 % by weight of cullet and 0.2–0.3 % by weight of sulfuric acid.

EFFECT: technical result is an increase of the core compressive strength.

1 cl, 1 dwg, 2 tbl, 1 ex

Description

The invention relates to building materials and can be used for the production of drywall products.

Reinforced materials with different compositions of gypsum plaster cores are known, such as highly effective fireproof gypsum cement compositions with increased water resistance and heat resistance for reinforced cement lightweight structural cement panels [Patent RU 2592307 (C2) - 2011-12-16].

The disadvantage of this solution is that the material is inferior to the developed gypsum plasterboard based on a modified gypsum binder in physical and mechanical characteristics, has a higher cost and more complex technology.

Closest to the proposed invention, the technical solution adopted for the prototype is the core of the drywall sheet, consisting of a binder [Patent RU 2200715 (C2) - 2001-05-24], consisting of gypsum and fly ash from burning anthracite mixed with water, the following ratio (wt.%):

building plaster - 70-80;

fly ash - 0-30.

However, the disadvantages of the prototype are its low strength characteristics.

The problem to which the invention is directed, is to increase the physico-mechanical properties of the core of drywall sheet (GCR), which can significantly increase its strength.

The technical result of the invention is to increase the compressive strength of the GCR core based on a modified gypsum binder.

This is achieved by the fact that the GCR core based on a modified gypsum binder contains gypsum, cullet, sulfuric acid and water, in the following ratio of components (wt.%):

gypsum plaster 46.4-52.6 cullet 13-20 sulphuric acid 0.2-0.3 water 33.3-34.2

Shredded cullet is introduced into building gypsum - glass powder, which acts as a filler, and together with sulfuric acid as a modifier, which allows to obtain new compounds in the structure of a modified gypsum binder.

Characteristics of the components used:

- building gypsum CaSO ₄ ⋅0.5H ₂ O (GOST 125-79) grade G-5, JSC "Khabez gypsum plant";

- cullet; The chemical composition of cullet was obtained by approximating the average values of various types of glass (Table 1):

- sulfuric acid H ₂ SO ₄ (GOST 4204-77);

- water (GOST 23732-79).

To study the effect of the composition of the GCR core on the physicomechanical characteristics, 4 composition of mixtures with different contents of the starting components were prepared.

Example (table. 2 composition No. 3). Cullet without sorting by chemical composition was crushed in a jaw crusher, the obtained glass powder was sieved through a No. 355 sieve, after which 30 grams of glass powder were taken and wet grinding was performed in a vibrating mill with the addition of 15 g of a 0.005 M sulfuric acid solution. Milling was carried out to a specific surface of 500-700 m ² / kg. Then the prepared mixture was placed in a paddle mixer with the introduction of 33.3 g of water and 46.5 g of gypsum. Samples were molded from the resulting mass according to GOST 23789-79 with a size of 40 × 40 × 160 mm. At the age of 7 days, physical and mechanical tests of the samples were performed. The test results are presented in table. 2.

For composition No. 2, the compressive strength reached 16.1 MPa, for composition No. 3 it was 16.6 MPa (Table 2), while the compressive strength of the prototype was only 15.5 and 15.7 MPa ( table 2).

In the prepared samples, sulfuric acid reacts with oxides of alkaline and alkaline-earth metals released from glass particles during grinding. The obtained sulfates of sodium, potassium and calcium (up to 80% of the mass of impurities in the glass) with stirring with building gypsum and further mixing increase its setting time, by slowing down the crystallization of building gypsum formed by silicic acid. Calcium sulphate, which even attached two water molecules during grinding, plays the role of a crystallization center during the hydration of the binder, sodium and potassium sulphates interact with gypsum particles, as a result of which pores are clogged with the formation of hydroglauberite and syngenite, respectively, the particles are overgrown with neoplasms and strengthen the gypsum stone matrix , which leads to an increase in physical and mechanical characteristics.

K ₂ SO ₄ + CaSO ₄ ⋅ 2H ₂ O → K ₂ Ca (SO ₄ ) ₂ ⋅H ₂ O + H ₂ O

10Na ₂ SO ₄ + 6CaSO ₄ ⋅ 2H ₂ O → 2Na ₁₀ Ca ₃ (SO ₄ ) ₈ ⋅ 6H ₂ O

These reactions are confirmed by x-ray phase analysis (figure 1).

Thus, only when the content in the composition of the core GCR based on the modified gypsum binder is 46.4-52.6 wt. % gypsum, 13-20 wt. % cullet, 0.2-0.3 wt. % sulfuric acid, trapped 33.3-34.2 wt. % water, an optimal material structure is created, thereby increasing the compressive strengths. With an increase in the content of components in the composition of the GCR core above those specified in compositions 2 and 3, the strength indicators decrease to 15 MPa, due to a violation of the matrix of the binder. With a decrease in the content of components in the composition of the GCR core lower than those indicated in compositions 2 and 3, the strength indices decrease to 14.3 MPa, due to the insufficient amount of the formed double salts - syngenite and hydrogluberite.

GCR is made by casting the obtained mass of the GCR core based on a modified gypsum binder onto a substrate (prepared base in the form of a cardboard sheet and fiberglass mesh) and then covered with a layer of mesh and cardboard sheet.

The use of the claimed invention will increase the strength characteristics of GCR, reduce costs, improve the ecological situation by processing cullet polluting the environment, increase the demand for drywall products in the building materials market. Unlike other existing technologies, one of the main advantages of the material is the use of a wide range of types of cullet without sorting by chemical composition.

In addition, when using optical glass waste (flints), the material has radiation protective properties against β radiation.

Claims (2)

The core of the gypsum plasterboard based on a modified gypsum binder, including building gypsum and water, characterized in that it additionally contains cullet and sulfuric acid in the following ratio of components (wt.%): gypsum plaster 46.4-52.6 cullet 13-20 sulphuric acid 0.2-0.3 water 33.3-34.2

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