RU2444435C1 - Method of producing three-layer construction articles - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to construction, particularly, to production of three-layer wall panels with central heat-insulation layer made from foamed polystyrene. Proposed method comprises filling the mould consecutively with inner structural concrete layer, heat-insulation layer and external structural concrete layer. Then, the panel is cured, steam cured and the mould is removed. 1.2-5 mm-polystyrene grains of polystyrene with mean density of 15-35 kg/m³ subjected to secondary pre-foaming for 5-12 min, are used as heat-insulation layer. The mould filled, articles are electrically heated to 80-95°C by 50 Hz-industrial-frequency current at 50-200 V and, then, cured in aforesaid mould for 10-50 min. After mould removal, article with temperature of 80°C is fed on pallet in steam curing chamber.

EFFECT: accelerated production, reduced electric power consumption.

2 ex, 1 tbl

Description

The invention relates to construction, and in particular to the manufacturing technology of three-layer building products, for example wall blocks or panels with an average heat-insulating layer of expanded polystyrene.

A known method of manufacturing three-layer wall panels, which consists in combining using metal ties or monolithic (prefabricated) concrete keys in a single design of two load-bearing layers and a heat-insulating non-concrete material located between them - polystyrene foam (Morozov N.V. et al. Three-layer wall panels for industrial and public buildings. - Concrete and reinforced concrete, 1977, No. 10, pp. 7-9).

The specified method of manufacturing three-layer panels is inefficient, because It is accompanied by large material and labor costs: scarce and expensive alloy steels and ordinary steels with metallized connecting elements are used to connect the layers together. In addition, the coefficient of thermotechnical uniformity of the structure is of low value.

The closest in technical essence and the achieved result to the described invention is a method for the production of a three-layer panel consisting of two outer concrete layers and a heat-insulating layer of polystyrene concrete enclosed between them (Chinenkov Yu.V., Korol E.A. Three-layer strip-cut panels with insulation from polystyrene concrete. - Concrete and reinforced concrete. - M.: Stroyizdat, 1997, No. 4, p.2-5).

The disadvantages of this method is the long duration of the process and the low strength of the boundary adhesion between the layers of the panel, caused by a sharp change in the properties of concrete on the interface between the concrete of the bearing layers and the heat-insulating concrete.

The aim of the invention is to accelerate the production process of products, increase the reliability of the connection of their individual layers and reduce energy consumption in the production process.

This goal is achieved by the fact that in the method of manufacturing a three-layer building products with a middle layer of expanded polystyrene, comprising sequential filling of the mold with an internal structural layer of concrete, a heat-insulating layer and an external structural layer of concrete, aging, steaming and stripping the product, according to the invention as a heat-insulating layer grains of polystyrene pre-foamed for 5-12 minutes are used for fractions of 1.2-5 mm with an average density of 15-35 kg / m ³ , after filling for 15-20 minutes we conduct electric heating of the product through electrodes with a current of industrial frequency 50 Hz at a voltage of 50-200 V, and after stripping the product with a temperature of 80 ° C is fed into the steaming chamber on a pallet.

The claimed technical result is provided:

1. Using as a heat-insulating layer of grains of pre-foamed polystyrene fractions of 1.2-5 mm with an average density of 15-35 kg / m ³ , which, when heated, increases in volume and penetrates into the outer layers, thereby creating transitional layers zones and contributing to an increase in the strength of the product at the boundaries of the layers.

2. The use of electric heating of molding materials with an industrial frequency current of 50 Hz at a voltage of 50-200 V for 15-20 minutes through electrodes located on the side faces of the mold.

3. Subsequent steaming of the deformed product, already heated to a temperature of 80 ° C, located on one pan.

The method is as follows.

A layer of concrete is poured into a special rigid form, perforated along two opposite faces, after which grains of a polystyrene fraction of 1.2-5 mm, previously foamed for 5-12 minutes, are poured onto it. Then the outer layer of concrete is laid. Then close the form with a lid, creating a closed volume. The form is connected to an alternating current network through electrodes located on the side faces, and the mass is subjected to electric heating with a current of industrial frequency 50 Hz at a voltage of 50-200 V for 15-20 minutes. After electrical processing, the product is aged for 10-15 minutes to relieve temperature stresses and gain structural strength. Then comes the stripping, after which the product on the pallet goes to further heat treatment, where it is steamed at a temperature of 80 ° C for 6 hours.

Electric heating of the mass is carried out up to 80-95 ° C. The polystyrene located in the central layer of the product foams evenly. As a result of the developing compaction efforts of polystyrene, an internal overpressure is created (up to 5 atmospheres), which squeezes mechanically bound water through the perforations of the mold and compacts the product by the equivalent volume squeezed out moisture. The mass of the heat-insulating layer is introduced into the outer layers of concrete, thereby creating transition zones and forming a monolithic product.

The cross-sectional articulation of different-density layers is a rough undulating surface. As a result, the contact area of the layers increases, providing reliable adhesion and increasing the strength of the material with a combined structure.

The mechanical squeezing of moisture during electric heating through perforation of the mold allows to reduce the time of subsequent steaming of the product without the mold on the pallet, in addition, the product after electric heating has a temperature of about 90 ° C, which eliminates the need to heat it in a steaming chamber and also reduces the time of heat and moisture treatment and energy consumption.

The application of this method allows to accelerate the manufacturing process of three-layer products by combining the operations of final foaming of polystyrene, compaction and heat treatment of the product in one technological redistribution, as a result of which there is no need for holding between laying layers. The monolithic-layered products manufactured by this method in one technological process have a transition layer, which contributes to an increase in strength, reliable adhesion and good joint work of the monolith. The method of creating a three-layer systems allows you to abandon vibration compaction when forming products. The design created in this way is not limited in the choice of configuration and volume.

Thus, it is possible to produce large-sized bearing and self-supporting wall enclosing structures, as well as multi-layer blocks, which eliminates the need for reinforcement.

Examples of the method

Example 1. Prepare a molding concrete mixture of the inner and outer layers of the following composition (consumption per 1 m ³ ): cement - 200-264 kg, sand 756-800 kg, crushed stone - 1200 kg, water - 120-160 l. The average density of the outer layers is 2300-2500 kg / m ³ . The resulting mass is placed in a rigid perforated form, forming the inner supporting layer of concrete. After that, grains of expanded polystyrene fractions of 1.2-5 mm are covered with a grain, creating a heat-insulating layer, and the outer concrete layer is laid next. The mold is closed with a lid, an alternating current of 50 Hz is supplied to the plate electrodes and electric heating is carried out for 15-20 minutes at a voltage of 50-200 V. Then there is exposure, stripping and steaming on a pallet at a temperature of 80 ° C for 6 hours.

Example 2. The technology according to example 1, but polystyrene grains use a monofraction composition.

Table 1 Product Feature Comparison The properties Example 1 Famous The average density, kg / m ³ thermal insulation layer 30-50 300-500 dense layers 2300-2500 2300-2500 The limit of compressive strength, MPa thermal insulation layer 0.12-0.29 0.64-1.0 dense layers 25.3-35.5 21.1-29.6 Thermal conductivity, W / m ° С thermal insulation layer 0,036-0,04 0,082-0,131 dense layers 1.88-1.92 1.85-1.9 Energy consumption per 1 m ³ products, kg steam 75 150 Technological cycle time, h 7 fifteen

Claims (1)

A method of manufacturing a three-layer building products with a middle layer of expanded polystyrene, including sequential filling of the mold with an internal structural layer of concrete, a heat-insulating layer and an external structural layer of concrete, exposure, steaming and stripping of the product, characterized in that the grains previously foamed into for 5-12 minutes, polystyrene fractions of 1.2-5 mm with an average density of 15-35 kg / m ³ , after filling out the form for 15-20 minutes is carried out electro heating of products to a temperature of 80-95 ° C through electrodes with a current of industrial frequency 50 Hz at a voltage of 50-200 V, followed by exposure of the products in the mold for 10-15 minutes, and after stripping the product with a temperature of 80 ° C is fed into the steaming chamber the pallet.