SU1252324A1 - Method of manufacturing concrete and reinforced concrete articles - Google Patents

Description

The invention relates to the manufacture of concrete and reinforced concrete horizontal structures with a large open surface, such as polvv, ceilings, road surfaces, etc. and can be used to warm frozen ground.

The purpose of the invention is to increase the density and strength of concrete.

The method of making concrete and reinforced concrete structures is carried out as follows.

The concrete is laid and compacted. Then, electrodes are placed on a freshly molded and compacted structure and a layer of carbon-graphite production — coke fines, calcined at 1000–2800 ° C — is applied by electroconduction.

The distance between the electrodes and the thickness of the calcined coke breeze layer, which characterize the electric power of the heater, depends on the ambient temperature, the temperature mode of heating products, the electric power capabilities of the construction site, and is determined by preliminary calculation. A layer of calcined coke 5–6 cm thick is optimal from the point of view of electrical conductivity, water discharge and economy. The dispersed structure of the heater creates the possibility of a capillary suction from the concrete mixture of excess mixing water, reducing the water-cement ratio, which leads to an increase in the density and strength of the concrete after its heat treatment. The stability of the electrical properties of the carbon granular material ensures the stability of the temperature field over time, which makes it possible to apply any, including the most effective, thermal holding mode.

Thus, the use of electro-thermoactive granulated material solves in a complex the task of creating the required temperature conditions for the hardening of concrete mixes, as well as for removing excess mixing water from the material of moldable concrete and reinforced concrete structures, which contributes to the achievement of improved concrete properties.

Strip steel with a thickness of 2–3 mm and a width of 30–50 mm is used as current-carrying electrodes.

The calcined coke breeze is a waste of carbon-graphite production, namely, thermal insulating bulk material of kiln or graphite-burning furnaces, which are used for high-temperature (1000 -) processing of raw graphite products. In the process of high-temperature processing of the products, the overfilling is calcined and graphitized, thus acquiring the property of electrical conductivity. Moreover, the higher the processing temperature, the higher the conductivity of the material. Processing temperature range 1000 - is

a condition in which the electrical conductivity of the coke transfer charge increases dramatically. Electrically conductive transfer is not reused and goes to the dump. This material is easily transported, can be stored in open warehouses at any temperature and any natural moisture, which does not affect its properties. The use of waste coke breeze in construction also addresses the issue of recycling a by-product of carbon and graphite production.

Example. Concrete samples of the following composition are molded, kg / m: Portland cement 295; river sand with M "2.1 735; granite rubble 1180; water" from the city's water supply network.

The ductility of concrete over a standard cone is 13 cm.

Samples — cubes (12 pcs.) Of size lOOxlOOx X100 mm and sample cylinders (6 pcs.) With a diameter and height of 150 mm in the amount of 6 pcs — are formed from the concrete mixture. for heating each layer of coke breeze.

After molding the sample cubes and cylinder samples, they are maintained at 15 ° C and relative humidity of 60Z for 2 hours, after which they are heat treated with five kinds of coke breeze, calcined at 600, 950, 1000, 1500 and 2800 C. Heat treatment is carried out mode: temperature rise 4 hours; isothermal aging 6h; cooling 4h.

After the first vanishing, the heat-treated cubic samples are tested for compressive strength on a 50-ton press, and the cylindrical specimens are tested for water-tightness on a compression unit. The average test results are presented in the table.

Temperature - naxnnal, used in the technology of calcination and graphitization of carbon graphite products.

Editor I. Derbak

Compiled by V.Lebedeva

Tehred M. Margektal Proofreader T. Kolb

Order 4586/26 Circulation 640 Subscription VNIIPI USSR State Committee

On affairs of inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

P | x} Industrial and Printing Enterprise, Uzhgorod, Projecto st., 4

Claims (2)

METHOD FOR MANUFACTURING CONCRETE AND REINFORCED CONCRETE STRUCTURES, including laying of concrete mixture, compaction, placement of electrically conductive layer and electrodes on the surface of densified concrete, and subsequent electrothermal treatment of the product, characterized in that, in order to increase the density and strength of concrete, the electrically conductive layer is deposited onto the surface of the conductive layer coke breeze calcined at 1000 - 2800 ° C. 3 £ No. SP bf so b f 1252324