RU2276764C2 - Method for arrangement of lining from heat-resistant concrete - Google Patents

Abstract

FIELD: erection of linings of heat engineering structures, in particular, mines, furnaces, reactors, etc. of monolithic reinforced concrete.

SUBSTANCE: the method includes preparation of a heat-resistant light=concrete mix with a cone settling within 11 to 12 cm at the following relation of components, percent by mass: high alumina cement - 15.0-20.0, slag pumice, fractions 5-10 mm, 5.16-18, fractions 10-20 mm, 23.95-24, fractions less than 5 mm 37.5-42.5; lignin sulfonates 0.1-0.8; water to solid-to-liquid ratio 0.1-0.20, placement of the concrete mix between the metal jacketings of the thermal set, cure and drying according to the following regime: temperature rise from 18-20 to 100C-15-16 hrs, isothermal cure 50-56 hrs, temperature rise from 100C to 170-180C-10-11 hrs, isothermal cure - 120-125 hrs. Concrete density - 1600 kg/cu.m, compressive strength after 28 days - 18.1 MPa, 3 days after heating up to 600C - 12.5 MPa, thermal conductivity - 0.5W/m.C. Coefficient of linear thermal expansion - (10-12)10^-61/°C.

EFFECT: simplified construction of monolithic lining, at preservation of physico-mechanical and thermal properties of the lining, its durability and reduced time of drying.

1 ex, 1 tbl

Description

The invention relates to the construction of heat engineering structures, in particular mines, furnaces, reactors, etc., from monolithic heat-resistant concrete with fire resistance up to 1200 ° C.

A known method of a device for a monolithic heat-insulating lining, including the preparation of cast molding material, laying it between the casing of the furnace and the formwork, aging and drying / 1 /.

The disadvantages of this method are the need to use for workability highly plastic molding sand with a moisture content of 180-190% and prolonged drying, which entails the occurrence of destructive phenomena in the lining and the destruction of concrete.

Closest to the proposed method is a device for lining of heat-resistant concrete blocks, which are made by preparing a heat-resistant concrete mixture of the following composition, wt.%: High-alumina cement 15.0-20.0; slag pumice fractions of 5-10 mm 15.16-18.55; 10-20 mm 23.95-24.37; less than 5 mm 37.5-42.5; water to a water-solid ratio of 0.1-0.15, laying it between the metal casing of the casing of the thermal unit and drying at a temperature of 200 ⁰ C for 10 hours / 2 /.

The disadvantage of the proposed method is the inability to achieve the required for special thermal engineering structures, such as nuclear reactors, physico-mechanical characteristics of concrete with cast concrete casting technology, while the required lining durability is not achieved as a result of uneven moisture removal during drying.

The technical problem is to simplify the device of a monolithic lining while maintaining the physico-mechanical and thermophysical properties of the lining, durability and shortening the drying time due to the uniform removal of moisture during the drying process.

The problem is solved in such a way that in the method of lining of heat-resistant concrete, which consists in preparing a heat-resistant concrete mixture, including high-alumina cement, slag pumice fractions of 5-10 mm, 10-20 mm and less than 5 mm and water, laying it between metal plating the casing of the thermal unit and drying, according to the invention, the heat-resistant concrete mixture additionally contains lignosulfonates, the mixture is prepared with a precipitate of a cone of 11-12 cm in the following ratio of components, wt.%:

high alumina cement 15.0-20.0 slag pumice fraction 5-10 mm 15.16-18.55 fractions of 10-20 mm 23.95-24.37 fractions less than 5 mm 36.7-42.4 lignosulfonates 0.1-0.8 water to water-solid ratio 0.1-0.20

and drying is carried out according to the following mode, the temperature rise from 18-20 ° C to 100 ° C - 15-16 hours, isothermal exposure 50-56 hours, the temperature rise from 100 ° C to 170-180 ° C - 10-11 hours, isothermal exposure - 120-125 hours

The proposed method differs from the known composition of the heat-resistant concrete mixture laid between the casing, and the drying mode.

близкого к коэффициенту линейного температурного расширения металла кожуха (внутреннего лайнера), что позволяет снизить деструктивные явления в бетоне в зоне контакта с кожухом и повысить долговечность футеровки.The technical result of the proposed method is to obtain a cast heat-resistant concrete mixture with a cone draft of 11-12 cm, which allows the lining to be erected in a monolithic way with tight filling between the casing shells while maintaining the specified thermophysical properties of the lining, namely, the thermal conductivity λ of not more than 0.5 W / (m ° C) coefficient of linear thermal expansion

close to the coefficient of linear thermal expansion of the metal of the casing (inner liner), which allows to reduce the destructive phenomena in concrete in the zone of contact with the casing and increase the durability of the lining.

The technical result is achieved by selecting the composition of the mixture and obtaining a precipitate of a cone of 11-12 cm as a result of using lignosulfonate as a plasticizer, which does not affect the cement hydration process and provides the given mobility of the mixture, i.e. technological process.

The proposed drying mode is selected on the basis of experimental data from the condition of ensuring the stability of the casing metal from steam pressure during the drying process and uniform removal of moisture from concrete.

The method is as follows.

Heat-resistant concrete mix is prepared in a forced-action concrete mixer. First, a dry mixture of high-alumina cement and slag pumice is prepared, then water with a plasticizer is added in two stages.

The heat-resistant concrete mixture is fed by a concrete pump into the gap between the casing (liner) of the thermal insulation and the external metal sheathing (external liner) through manhole couplings arranged at different levels of the metal sheathing. The mixture is laid using a deep vibrator, which is installed alternately in the coupling hatch. Then carry out the exposure for three days.

The lining is dried with superheated steam, which is fed to the lining through a process opening between the protective screen and the outer skin, on which all hatches are open to supply steam directly to the concrete mass and remove evaporation water to the drainage channel. To increase the rate of moisture removal, an air flow of 1 atm pressure is used. To reduce the viscosity of the water, the massif of concrete is heated to a temperature of at least 100 ° C, which facilitates the filtration and exit of moisture from the concrete structure. For pumping water use pumping units and pipes with filters.

The maximum drying temperature of the liner of the reactor installation, depending on the elasticity of the liner metal, is selected at 180 ° C.

Drying is carried out according to the following mode:

1. The temperature rise from 20 ° C to 100 ° C - 15-16 hours

2. Isothermal exposure at 100 ° C - 56 hours

3. The temperature rise from 100 ° C to 180 ° C - 10 hours

4. Isothermal exposure at 180 ° C - 120 hours

The average drying time is 7.5 days.

The drying mode is controlled by thermocouples installed in the hottest area of the lining at a distance of not more than 10 cm from the heated surface.

Example.

High-alumina cement of grade 500 and 800 TU 21-60-84 MPSM USSR is used as a binder for lining the liner of a nuclear reactor with lead cooling.

As a filler using slag pumice fractions of 5-10 mm; 10-20 mm and sand fraction 0-5 mm Novolipetsk Metallurgical Plant. GOST 97-60-86.

As a plasticizer - modified technical lignosulfonate LSTM-2.

The mixture is prepared by sequentially introducing aggregate, cement and water with a plasticizer into the concrete mixer and mixing for 3-5 minutes. Samples of 15 × 15 × 15 cm and 7.07 × 7.07 × 7.07 cm are molded from the mixture. Compaction is performed on a standard vibratory plate. The samples are subjected to exposure for three days and drying according to the above regime.

The composition of the mixture and the physico-mechanical properties of the concrete lining are given in the table.

No. Indicator Composition, wt.% p / p one 2 3 four one High Alumina Cement 18.12 19.69 20,0 20 (M800) 2 Slag pumice fraction 10-20 mm 25.32 24.37 23.95 23.95 3 Slag pumice fraction 5-10 mm 14.68 15.16 18.55 18.55 four Slag pumice Fraction 0-5 mm 41.58 39.98 36.7 36.7 5 Water W / T / liter 0,125 / 200 0,115 / 184 0,1 / 160 0.2 / 350 6 Lignosulfonate 0.3 0.8 0.8 0.8 7 The compressive strength of concrete after MOT, MPa 12.0 12,2 12.5 22.8 8 Compressive strength after 28 days, MPa 17.1 17.4 18.1 34.2 9 The strength of concrete after exposure to lead melt, MPa 11.8 12.1 12,4 22.0 10 Concrete application temperature, ° С. 1000 1000 1000 1000 eleven The density of concrete, kg / m ³ 1622 1612 1600

Information sources

1. Sokov V.N., Ramazanov E.A. "Monolithic heat-insulating linings from self-sealing masses", M., 1999, pp. 109-112.

2. RU Patent PM No. 38347, cl. E 04 C 1/00, BI No. 16, 10.06.2000.

Claims (1)

The method of lining of heat-resistant concrete, which consists in preparing a heat-resistant concrete mixture, including high-alumina cement, slag pumice fraction 5-10 mm, 10-20 mm and less than 5 mm and water, laying it between the metal casing of the casing of the thermal unit and drying, characterized in that the heat-resistant concrete mixture additionally contains lignosulfonates, the mixture is prepared with a precipitate of a cone of 11-12 cm in the following ratio of components, wt.%: High Alumina Cement 15.0-20.0 Slag pumice fraction 5-10 mm 15.16-18.55 Fractions 10-20 mm 23.95-24.37 fractions less than 5 mm 36.7-42.4 Lignosulfonates 0.1-0.8 Water To a water-solid ratio of 0.1-0.20, and drying is carried out according to the following mode: temperature rise from 18-20 ° C to 100 ° C 15-16 hours, isothermal exposure 50-56 hours, temperature rise from 100 ° C to 170-180 ° C 10-11 hours, isothermal exposure 120-125 hours