CS239206B1 - Inorganic building material - Google Patents

Abstract

The invention relates to the protection of inorganic building materials against corrosion. The invention solves the protection of inorganic building materials from concrete and reinforced concrete against external aggressive solid, liquid or gaseous environments, especially of an acidic nature. The essence of the invention is the addition of iron powder waste resulting from processing (e.g. grinding, cutting, blasting) to the binder mixture, alone or in a mixture with iron mechanical powder. The action of the aggressive environment on the added iron powder waste causes its corrosion associated with the formation of rust. The formation of iron corrosion products seals the pores and capillaries in the binder mixture. This also dulls the aggressive medium and increases the diffusion resistance to penetration. The invention can be used to increase the resistance of inorganic building materials and structures made of them, especially from concrete and reinforced concrete, against the effects of aggressive environments. The process according to the invention can be used to protect; mainly delicate reinforced concrete structures, e.g. piles, clay-cement suspensions, cement waterproofing mixtures and sealants, from corrosion.

Description

(54)

ŠPAČEK ANTONÍN ióg. CSc .;

slaníCka Stefan ing., Bratislava

Inorganic building material

The invention relates to the protection of inorganic building materials against corrosion.

The invention solves the protection of inorganic building materials of concrete and reinforced concrete against an external aggressive environment of a solid, liquid or gaseous, in particular acidic nature. It is an object of the invention to add iron powder waste resulting from the treatment (e.g., grinding, cutting, blasting) to the binder mixture alone or in admixture with the iron mechanical powder. By corrosion of the aggressive environment to the added iron powder waste, its corrosion is associated with the formation of rust. The formation of iron corrosion products seals the feathers and capillaries in the binder mixture. This also dulls the aggressive medium and increases the diffusion resistance for penetration. The invention can be used to increase the resistance of inorganic building materials and constituents made therefrom, in particular of concrete and reinforced concrete, to the effect of aggressive environments. The process of the invention may protect; before corrosion, mainly subtle reinforced concrete structures such as piles, cementitious suspensions, cement waterproofing compounds and sealants.

239 206

- 1 239 206

The present invention is concerned with an inorganic building material with increased resistance to exposure to external aggressive environments.

From cement certificate No. 197 1 64 there is known a cement mix for concrete with increased resistance to aggressive water consisting of cement, filler and / or modifying additives and / or admixtures, characterized in that per part by weight of cement there is 0 01 to 3 parts by weight of iron powder with a minimum content of 98% by weight of iron (Fe) and a grain size such that it contains min. 5% by weight of particles smaller than 0.045 mm and a maximum of 15% by weight of particles thicker than 0.4 mm. This author's certificate also explains in detail the disadvantage and the low efficiency? in the use of iron salts such as chlorides, sulphates and nitrates, as well as certain industrial wastes (pyrites and iron filings).

Iron powder used according to MS. A0 197 164, however, must be produced by grinding the cut parts of iron wire, which is very costly. This disadvantage is overcome by the inorganic building material according to the invention. Its essence is that, in addition to the inorganic binder, modifying additives and / or additives and / or fillers, it contains, based on 1 part by weight of the inorganic binder, a min. 0,02 and up to 3 parts by weight of ferrous powder waste resulting from surface treatment (eg grinding, blasting, cutting) of iron, steel or paper semi-finished products with a fineness of maximum 15% by weight of particles more than 0,5 mm thick; and min.

% of particles finer than 0.125 mm and with a metallic iron (Fe) content of min. 5% by weight.

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It is preferred _; that iron powder waste is produced by surface treatment without the use of additional additives - liquid, paste or solid, which, by their presence in the iron powder waste, can act as pollutants produced by the binder.

By admixing iron powder containing metallic iron into inorganic binders such as cement or water glass binders, the corrosion of the aggressive medium, e.g. by the action of carbonic and acidic water, wet gases and the like, results in the rusting process of metallic iron particles. The resulting products of iron corrosion - iron oxides, resp. their hydrates and iron hydroxides, colmatize in the binder hardened slurry, mortar, mastic or concrete, capillaries and pores. It has been found that the thickness of the sealing layer is 1-7 mm depending on the diffusion resistance of the aggressive medium penetrating into the binder in the case of exposure of the external apheresis medium to the building material according to the invention. By contact of an aggressive environment against metallic iron particles, the effective concentration of the aggressive medium is also reduced.

The following examples show the possibilities of using and demonstrating the protective properties of an inorganic building material according to the invention

Example 1

In order to demonstrate the protective effects of iron powder waste, abrasive waste resulting from the grinding of engine block castings by carborundum grinding wheels by the dry process of the following granular composition was used:

Size "sewn [mm]

0.5

0.25

0.125

0,063

0,045 overflow over 0,045

Sieve residue in% wt

0.5

24.9

69.4

4.5

0.5

0.4

Together

100.0

- 3,239,208

The metal iron content determined by chemical analysis in this abrasive waste was 8.2 wt%. This abrasive waste was used to prepare 3 4x4x16 cm mortar beams according to CSN 72 2117 Cement Strength Determination. The mortar mixture had the following composition:

Cement PC 4C0 360 gr

Abrasive waste 90 g

Fine granulometry sand fine 450 g

Sand of continuous granulometry medium 450 g

Sand of continuous granulometry 450 g thick

Water 225 rol

After 1 day of wet storage, the mold was removed and the beams were stored in water for 27 days. After a 28 day baseline treatment, the strips were placed in a carbonic aggressive solution containing 70 mg aggressive CO ₂ / L. Already on the third day of exposure, the surface of the beams began to stain with the formation of rusty fumes of the reaction of aggressive carbon dioxide from aggressive water with metallic iron from abrasive waste, which sealed its surface against the effects of aggressive environment.

Example 2 < tb > < tb > < tb > < tb > ______________________________________ < tb >

Velkost? sieve opening [mm] Sieve residue in% wt.

0.50 '0.250

0.125

0,063

0,045 overflow over 0,045

Together

0.7

1.3

9.1

13.5

75.4

100.0

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The iron iron (Fe) content in the abrasive dust as determined by chemical analysis was 86.3% by weight. In accordance with UN 722117 cement strength determination, 3 pieces of 4x4x16 cm mortar beams were made using the following abrasive drift:

Cement PC 4CO 360 g Abrasive drift 90 g Fine granulometry sand 450 g Fine granulometry sand medium 450 g Fine granulometry sand 450 grit Water 225 ml

After 1 day of wet storage, the crystals were demolded and stored in water for 21 days. After a 28 day baseline treatment, the strips were placed in water containing 70 mg of aggressive CO2 / L. The rust color of the beam surface was observed as early as the second day of exposure of the beams in the aggressive solution and was more intense than when using the abrasive waste of Example 1.

Example 3

The abrasive drift of the granulated composition and the metallic iron content according to Example 2 was used to prepare a concrete mixture of this composition for 1 m ^ h.b,

Cement PC 400 500 kg Grinding drift 76 kg Fine aggregate 0/8 mm 635 kg Aggregates 8/16 mm thick 960 kg Water 225 1

Test specimens of 15x15x15 cm were made from the concrete of this composition to determine strength. The specimen fragments after the strength test were placed in a carbon dioxide aggressive solution containing 70 mg aggressive COg / L.

- 5,239 20β

Rusty staining of the debris surface appeared already after a few days of exposure in aggressive solution and after 11/2 months when the test was completed - it was very intense.

Example 4

The abrasive drift of the origin, granulometric composition and metallic iron content given in Example 2 was used to prepare a composition of the following composition:

Sodium water glass 225 g Abrasive drift 50 g Sodium fluorosilicate 34 g Silica drift 50 g Silica sand ground 125 g

A triple coat of the above composition was used to protect 4x4x16 cm mortar beams prepared from a 1: 3 mixing mortar. After 7 days of depositing the coated beams in dry air, the beams were placed in carbonated, aggressive water containing 70 mg of aggressive COg / L. After 2 days of exposure, the paint began to stain from the emerging rust, which sealed the pores and capillaries to protect the paint and the underlying beam from corrosion. Color with increasing exposure time intensified and over the years, when the observation was completed, the exterior appearance of the coating did not show corrosion changes.

The iron powder additive (admixture) may be used in inorganic binder slurries, mortars, concretes and cements to increase their chemical resistance, in particular to the action of carbonic aggressive waters, waters exhibiting combined leaching-carbon aggressiveness (mercury carbonic waters) and acidic waters.

The sealing and protective effect of the organic building material according to the invention is also caused by the action of other aggressive media which, in conventional reinforced concrete, cause corrosion of the steel reinforcement, such as moist and / or acid gases, chlorides and others. The metal content of the iron can be corrected in the abrasive waste by the addition of MC 20 iron powder according to CSN 41 8003 and / or MG 30 according to CSN 41 8004 and / or MC 12 according to CSN 41 8002 and / or MC 10 according to CSN 41 8001.

Claims (3)

PRBBIFFIT OF THE INVENTION 239 208 An inorganic building material of enhanced chemical resistance, consisting of an inorganic binder and optionally modifying additives and / or additives, characterized in that it contains at least 1 part by weight of binder min. C, C2 and max. 3 parts by weight of iron powder waste with a fineness such that it contains max. 13% by weight of particles larger than 0.5 mm and min. 1% of particles finer than 0.125 mm with a metallic iron (Fe) content of min. 5% by weight. <2. The inorganic building material according to claim 1, characterized in that it contains, in addition to the iron powder waste, also the iron mechanical powder in such a proportion that at least 1 part by weight of the iron powder waste is min. 0.05 β max 20 parts by weight of iron mechanical powder. Printed by Moravske tiskarske zavody, Price: CZK 2.40s operation of 12, the People's Militia class 3, Olomouc