RU2190581C1 - Method of heat-resistant concrete producing - Google Patents

Abstract

FIELD: building materials. SUBSTANCE: method of production of heat-resistant concrete involves mixing Portland cement with an addition preparing by wet grinding silica-containing components and alkaline component, chamotte crushed stone and chamotte sand. Method involves an additional addition in grinding a refractory material with content of Al₂O₃ above 68% and water glass with density 1.41-1.47 g/cm³ is used as an alkaline component and quartz sand is used as a silica-containing component. Grinding is carried out up to preparing 7-8% of residue on sieve 63 mcm followed by drying. Invention can be used in making heat-resistant articles made of concrete on the base of Portland cement and making heat-resistant concrete used for a monolithic fettling of different heat aggregates. Invention provides making heat-resistant concrete with temperature using 1300 C and its cost is decreased by 2-3 times as compared with the available prior art. EFFECT: improved method of concrete production, improved properties, decreased cost. 3 tbl, 1 dwg

Description

The invention relates to the industry of refractory materials and can be used for the manufacture of products from heat-resistant concrete or commodity heat-resistant concrete during the construction of thermal units with operating temperatures of more than 1300 ^o C.

 A known method of producing heat-resistant concrete based on Portland cement with refractory components (monolithic crushed stone and fireclay sand).

The disadvantage of this method is the relatively low temperature of the use of heat-resistant concrete - 1100 ^o C (see the Handbook of the builder "Construction of industrial furnaces" edited by IA Shishkov, 6th edition, Moscow, Stroyizdat, 1986, pp. 74-75 ), while the temperature of the use of chamotte products, the waste of which is used to produce chamotte crushed stone and sand, is 1350 ... 1400 ^o С (Refractory products, materials and raw materials. Reference book. 4th edition. Moscow, Metallurgy, 1991 , p. 35).

A known method of producing heat-resistant concrete with a temperature of 1300 ^o C on the components of chamotte crushed stone and sand and using as a binder liquid glass or alumina cement (see SNiP 2.03.04-84, p. 21, composition 16, 19).

 The disadvantage of this method is the high cost of the binder and, as a consequence, the high cost of heat-resistant concrete both on water glass and on alumina cement.

 In the closest analogue method (copyright certificate 2070872) is the production of heat-resistant concrete by mixing Portland cement, an additive obtained by wet grinding silica-containing components and an alkaline component, chamotte crushed stone and chamotte sand, where opal-cristobolite rock is used as a feedstock.

The goal is achieved by a method of producing heat-resistant concrete by mixing Portland cement, an additive obtained by wet grinding of silica-containing components and an alkaline component, chamotte crushed stone and chamotte sand, when grinding, an additional refractory material with an Al ₂ O ₃ content _of more than 68% is added, and as an alkaline component liquid glass is used with an acidity of 1.41 ... 1.47 g / cm ³ , and silica-containing component as a silica-containing component, and grinding is carried out to obtain a residue on a sieve of 63 microns 7 ... 8%.

The ratio of the feedstock to the ball mill,%:
Fireclay brick waste - 90-95
Quartz sand - 5-10
The feedstock is loaded into a wet ball mill.

 Upon receipt of the appropriate grain composition, the mixture is dried, after which it is mixed with Portland cement.

 Next, refractory components and Portland cement with an additive are fed into the mixer.

 For a comparative assessment of the effect of finely ground chamotte additive (TSH) and dried concentrated cementitious slurry (PBC) on the properties of heat-resistant chamotte concrete, mixtures of the following compositions were prepared (Table 1).

The choice of the optimal H / C was made based on the criterion of achieving the necessary mobility of the mixture under the accepted molding conditions. Sample cubes with an edge of 50 mm were prepared in metal collapsible forms by vibroforming with a load. The compaction parameters of the mixtures were as follows: specific gravity static pressure of 0.1 kg / cm ² , vibration frequency of 50 Hz, amplitude 0.3 mm. The duration of vibration compaction in all cases was 1 min.

Samples made as described above were stored for 7 days at a temperature of 18-22 ^o C in wet conditions. After maturation, the samples were dried at a temperature of 100-110 ^o C to constant weight, cooled to room temperature and subjected to tests. The properties of the samples were determined by standard methods.

The residual compressive strength of heat-resistant concrete after heating to 800 ^° C at a speed not exceeding 150-200 ^° C for 1 hour was kept for 4 hours at 800 ^° C and then cooled together with the furnace to room temperature. After cooling, three cubes were tested for compression. Residual compressive strength:
R _rest = (R ⁸⁰⁰ / R ¹⁰⁰ ) 100%,
where R ⁸⁰⁰ and R ¹⁰⁰ are the compressive strengths of the samples, respectively, after heating to 800 ^o C and dried at 100 ... 110 ^o C, kg / cm ² .

 Of the three results obtained by testing the samples for compression, the average value was taken. If one smallest result differed by more than 20% from the next, larger indicator, the ultimate strength was determined by the two largest results.

 The results of tests of samples of various compositions are given in table.2.

As follows from the data table. 2, the introduction of the composition of the concrete mixture KVS instead of finely ground fireclay additives for all investigated compositions:
1) provides an increase in the strength of concrete indicators by 1.2-1.5 times;
2) helps to increase their residual strength after heat treatment at 800 ^o C;
3) allows to increase the refractoriness of materials to 1690 ^o C.

 The method is illustrated in the drawing.

 Also, studies have shown that the introduction of PIC in the concrete mixture improves its mobility and workability. This, apparently, can be explained by the plasticizing properties of the highly dispersed (colloidal phase) FAC. As a result, concrete mixtures prepared with the addition of a dried binder suspension are well formed at low W / C (see Table 1), thereby ensuring a higher density and strength of concrete samples.

 Table 3 shows reference data on the characteristics of typical chamotte concrete on alumina and high alumina cements.

 Concrete products (chamotte blocks) - according to TU 14-8-130-74.

Brands: ШБВЦ-42 - on high-alumina cement with a mass fraction of Al ₂ О _{3 of} at least 42% (for use at temperatures up to 1350 ^o С), ШБВЦ-40 - the same, with a mass fraction of Al ₂ О _{3 of} at least 40% ( up to 1300 ^o C); ШБВЦ-38 - on alumina cement with a mass fraction of Al ₂ О _{3 of} at least 38 (up to 1250 ^o С); ШВВЦ-36 - the same, with a mass fraction of Al ₂ О _{3 of} at least 36% (up to 1100 ^o С). They are made of chamotte aggregates on high alumina and alumina cement. Designed for lining of thermal units.

 A comparative analysis of the properties of experimental PC concrete with the addition of dried KVS and typical chamotte concrete on alumina and high alumina cements allows us to draw the following conclusions.

 1. The use of a concentrated cementitious slurry as a micro-filler allows obtaining chamotte heat-resistant concrete at PCs that are not inferior in a number of indicators to a similar class of concrete on alumina and even high alumina cements.

2. Introduction to concrete mixtures of PIC in the amount of 18-24% (respectively Portland cement in the amount of 6-12%) allows you to get durable fireclay concrete PC with a temperature of application up to 1300 ^o With the following requirements for the components:
- Portland cement should have a brand of at least 500 and sufficient activity;
- it is necessary to use chamotte aggregate with an Al ₂ O ₃ content _of at least 36%;
- FAC used in the form of a micro-filler should have a sieve residue of 0.063 μm of not more than 8% and an Al ₂ O ₃ content _of not less than 68%.

Claims (1)

A method of producing heat-resistant concrete by mixing Portland cement, an additive obtained by wet grinding a silica-containing component and an alkaline component, chamotte crushed stone and chamotte sand, characterized in that when grinding, an additional refractory material with an Al ₂ O ₃ content _of more than 68% is added as an alkaline component liquid glass with a density of 1.41-1.47 g / cm ^{3 is used} , silica sand is used as the silica-containing component, and grinding is carried out to obtain a residue on a sieve of 63 microns 7-8%, followed by drying.

Images