RU2597336C1 - Fibre-gypsum-vermiculite-concrete crude mixture for making fireproof coating - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to the industry of construction materials and can be used in industrial and construction organisations for fireproofing building structures. Fibre-gypsum-vermiculite-concrete crude mixture for making fireproof coating contains, wt%: gypsum 40.0-47.7; expanded vermiculite 35.40-45.33; volcanic ash 3.0-3.5; portland cement 10.0-12.1; basalt fibre 1.2-1.5; saponified wood resin 0.07-0.1.

EFFECT: technical result is higher fire-resistance of building structures due to wider raw material base, increased strength and water-resistance of gypsum-vermiculite-concrete, increased crack resistance and fire-retardant properties of coating during fire.

1 cl, 3 tbl

Description

The invention relates to the construction materials industry and is intended for fire protection of steel, reinforced concrete and reinforced cement structures in civil and industrial construction.

Known flame retardants on Portland cement, gypsum, water glass, alumina cement with various additives [1, 2, 3, 4]. Expanded vermiculite and perlite are used as porous aggregates.

The closest are raw mixes for the manufacture of fire-retardant coatings using gypsum, expanded vermiculite, volcanic tuff sawing waste, quicklime and saponified wood resin [5].

The disadvantages of these compositions are the lack of a sufficient raw material base for volcanic tuff sawing waste, a relatively low tensile strength and bending of gypsum-vermiculite concrete, a relatively high thermal conductivity and low crack resistance of the coating at high temperatures during a fire.

The objective of the invention is to expand the raw material base, increase the strength and water resistance of gypsum vermiculite concrete, increase crack resistance and fire retardant properties of the coating during a fire.

The problem is solved through the use of gypsum, expanded vermiculite, volcanic ash, Portland cement, basalt fiber and saponified wood resin (SDO) in a fire retardant raw material mixture.

In the experiments, a gypsum binder of the Ust-Dzhegutinsky gypsum plant of the G-5 BII grade, portland cement PTs500-DO produced by Belgorodsky Cement CJSC were used. As an active mineral additive, volcanic ash of the Zayukovsky deposit of a fraction of 0-0.16 mm was used.

The chemical composition of volcanic ash is presented in table 1.

Aggregate - expanded vermiculite of the St. Petersburg mica factory fraction 0.16-5 mm.

The particle size distribution of expanded vermiculite is shown in table 2.

For dispersed reinforcement of the composite, basalt fiber manufactured by Ivotsteklo OJSC of the RNB-9-1200-4s grade was used, the ratio of fiber length to diameter based on preliminary experiments was taken ^l / _d = 1444.

To improve the rheological characteristics of the fire retardant mixture and the physicomechanical properties of the mortar and concrete, we used the surface-active air-entraining additive SDO developed by the All-Russian Research Institute of Iron Reinforced Concrete and Central Research Institute of Chemical Engineering (TU-81-05-2-78).

The preparation of the mixture is carried out in a forced-action mixer, in which, after supplying water with the addition of SDO, a mixture of gypsum, Portland cement, volcanic ash, basalt fiber, then expanded vermiculite, or a premixed dry mixture of gypsum, Portland cement, volcanic ash, basalt fiber and expanded vermiculite. Mixing of all components is continued until a homogeneous fibro-gypsum-vermiculite-concrete raw material mixture is obtained. The duration of mixing the mixture is 1.5-2 minutes

To study the fire-retardant effectiveness of the proposed fire-retardant fiber-gypsum-vermiculite-concrete compositions, cement-cement slabs with a fire-retardant layer were formed. The cement-cement layer was formed on a standard vibrating platform, the fixation of the fine mesh and bar reinforcement is performed by known methods. The fire-retardant layer is formed by injection molding and natural drying is carried out in air-dry conditions. Fire retardant coating is also applied to metal, reinforced concrete and reinforced cement structures at the construction site by hand or mechanized using plaster aggregates of domestic or foreign production.

Fire tests were carried out on samples with dimensions of 190 × 190 mm on an electric furnace in a horizontal position according to the temperature regime of a “standard” fire, regulated by GOST 30247.0-94. The fire resistance limit on the bearing capacity (R) of reinforced cement slabs was estimated by heating the woven mesh in the structural layer (at the boundary of the layers) to 300 ° C. The moisture content of the fine-grained concrete of the cement-cement layer and the flame retardant composition at the time of testing was 3-4% and 8-10%, respectively. During the fire tests of the two-layer elements, violations of their integrity were not detected.

The compositions of the fiber-gypsum-vermiculite-concrete fire-retardant raw material mixture according to the invention and their main physicomechanical properties, fire resistance limits of two-layer reinforced cement slabs are shown in table 3. Table 3 also shows the results of comparative tests of reinforced cement slabs with a fire-retardant layer based on control compositions using volcanic tufa fraction 0 sawing waste -2.5 mm.

Table 3 shows that, at a lower average density, the developed composites have higher compressive and bending strengths. This is because the ash is used fractions up to 0.16 mm, which increases the content of the chemically active component in contrast to the tuff sand fractions up to 2.5 mm used in the prototype.

The introduction of basalt fibers increases the compressive strength of the fiber-gypsum-vermiculite-concrete composite by 1.17 times, and when bending, by 1.73 times with respect to the strength of the initial matrix. Compared with the prototype, the compressive strength of the fiber-gypsum-vermiculite-concrete composite is increased by 2.05 times, by bending - by 2.12 times. This will make it possible to produce large-sized fiber-gypsum-vermiculite-concrete products. In addition, reinforcing the initial matrix with basalt fibers increases the crack resistance and fire retardant properties of the coating due to the perception of tensile temperature stresses during a fire. The developed fiber-gypsum-vermiculite-concrete composite has an increased softening coefficient of 0.7-0.75, which will also expand the scope of their effective application.

Information sources

1. Strakhov V.L., Garashchenko A.N. Fire protection of building structures: modern means and methods of optimal design // Building materials. 2002. No.6. S. 2-5.

2. Copyright certificate of the USSR No. 275342. IPC E04B 1/94. Composition for coating metal elements / Schipanov A.I., Labozin P.G. // B.I. No. 22, 07/03/1970.

3. Guidance on the composition and use of heat-insulating and fire-resistant perlite plasters. M .: Stroyizdat, 1975 .-- 15 p.

4. Guidelines for the implementation of fireproof and heat-insulating plasters in a mechanized way. M .: Stroyizdat, 1977 .-- 46 p.

5. Khezhev T.A., Khezhev H.A. RF patent No. 2385851. The raw material mixture for the manufacture of fire retardant coatings // Bull. No. 10. 2010.

Claims (1)

Fiber-gypsum-vermiculite-concrete raw material mixture for the manufacture of a fire-retardant coating, including gypsum and porous aggregates, characterized in that it contains expanded vermiculite of the 0.16-5 mm fraction and volcanic ash of the 0-0.16 mm fraction, which is also an active mineral additive, as aggregates and as additives - Portland cement, basalt fiber and saponified wood resin in the following ratio of components, wt.%:
Gypsum 40.0-47.7 Expanded Vermiculite 35.40-45.33 Volcanic ash 3.0-3.5 Portland cement 10.0-12.1 Basalt fiber 1.2-1.5 Saponified wood resin 0.07-0.1