RU2641363C1 - Method of manufacturing products under pressure from high-strength fibrous concrete - Google Patents

Abstract

FIELD: construction.SUBSTANCE: method of manufacturing products under pressure of high-strength fibrous concrete, by which reinforcement is installed (if necessary) and concrete mixture is laid in the mould cavity. Thereinafter, the mould is closed and pressure is created inside the mould by means of a press, whereby the concrete mixture is pressed out. After the concrete has gained strength, the product is released from excess pressure and removed from the mould. Wherein the concrete mixture is filled with metallic or non-metallic fibres before the concrete mixture is laid in the mould, whereby fibrous concrete is obtained. The concrete mixture laid in the mould is held therein at a pressure of not less than 2.5 MPa before gaining the stripping strength, but not less than for 240 minutes. The hardening concrete mixture is heated to a temperature of not more than 80°C due to feeding a coolant inside the mould cavity. Wherein the coolant temperature for heating up the products to be moulded should not exceed 95°C, and the temperature increase rate should not exceed 35°C per hour.EFFECT: improving the technical characteristics of products, reducing the reinforcement consumption, reducing the labour intensity and the work implementation time.4 dwg

Description

The invention relates to the field of construction, namely the production of reinforced concrete products by hardening of concrete under pressure, and can be used for road, bridge and airfield construction, in the manufacture of reinforced concrete products and structures made of fiber concrete. In particular, the invention relates to a method for manufacturing pressure products from high-strength fiber-reinforced concrete, such as, for example:

- sleepers, foundations, bridge coverings, shore protection strips;

- industrial and industrial floors, tunnels;

- roads, strips for takeoff and landing at airfields, sidewalks;

- paving and road tiles, border material;

- frame construction, monolithic structures;

- channels for drainage, well shafts for sewers, dams, water treatment systems and structures exposed to heavy loads;

- and other.

A known mold for the manufacture of concrete and reinforced concrete products according to the copyright certificate of the Russian Federation No. 1821372, class. B28B 3/04, 1993, in which the method of vibration pressing of products was used.

The manufacture of products in this mold is as follows.

The reinforcing cage of the product is installed in the prepared formwork cavity, then the formwork surface of the punch is closed inside the formwork cavity, then concrete mixture is fed into the formwork cavity through the loading hole and, at the first stage, it is sealed with a mounted vibrator, then the loading hole is sealed with a plug, then the concrete mixture is subjected to pressure, compacting it and squeezing out excess moisture, is kept under pressure for 10-15 minutes, after which the pressing organ is turned off, concrete see Referring remains pressurized and solidified to set its stripping strength, while it is warmed by supplying a coolant disconnect pressing surface of the upper surface of the article, the finished article is lifted from the mold and taken out of it.

However, the products obtained by the described method have sufficient strength for the manufacture of structures that do not require increased strength, but require significant consumption of reinforcement, have a high complexity and lead time.

A known mold for the manufacture of concrete and reinforced concrete products and a side compression mechanism according to the patent of the Russian Federation No. 2274547, class. ВВВ 7/06, 2006, with the help of which the method of manufacturing products under pressure, adopted by the applicant as a prototype, is carried out.

The manufacture of the product is as follows.

In the cavity of the formwork of the prepared mold, install (if necessary) reinforcement and lay the concrete mixture. Then set the cover with mounting elements and using a press to create a force on the cover. In this case, the elements of the movable formwork are moved relative to the power frame, the spacers are rotated, and elastic liners are crushed and the concrete mixture is compressed. When the necessary concrete compaction is achieved, the cover is fixed to the power frame using hinged bolts.

When the concrete is set to the appropriate strength, the folding bolts are untwisted, the product is freed from excess pressure and the cover is removed from the power frame. In this case, the elastic liners unclench the elements of the movable formwork, as a result of which the formwork gap is formed and the product is removed from the formwork and the mold.

However, the strength characteristics that the products possess do not allow their use in road surfaces, floors, i.e. where high strength is required, for example, in bridge coatings, take-off and landing strips at aerodromes, etc.

The technical task of the claimed invention is the creation of a technological process that allows to improve the technical characteristics of products, reduce the consumption of fittings, reduce not only the cost, but also reduce the complexity and timing of work.

The problem is solved in that in the proposed solution, the concrete mixture for the manufacture of products before laying it in the mold is filled with fiber fibers metal or nonmetallic, whereby fiber concrete is obtained, the concrete mixture placed in the mold is kept in it under pressure at least 2.5 MPa to a set of stripping strength, but not less than 240 min, and the hardening concrete mixture is heated to a temperature of not more than 80 ° C due to the supply of coolant inside the mold cavity, and the coolant temperature for heating of molded products should not exceed 95 ° C, and the rate of temperature increase should not exceed 35 ° C per hour.

The technical result from the use of the invention is to improve the operational characteristics of the products, namely: due to the use of fiber fibers in the concrete mixture and the observance of the process of hardening fiber concrete under pressure and temperature conditions up to 30% increased strength, increased resistance to physical stress, minimized the formation of shrinkage cracks .

In FIG. 1 shows a mold for the manufacture of articles under pressure from high-strength fiber-reinforced concrete, general view, vertical section;

in FIG. 2 is a general view, a vertical section, a mold after filling and applying pressure;

in FIG. 3 is a horizontal section AA in FIG. 1, the mold before filling and applying pressure;

in FIG. 4 is a horizontal section BB in FIG. 2, the mold after filling and applying pressure.

To implement the method of manufacturing products under pressure from high-strength fiber-reinforced concrete, a mold is used that contains a fixed power frame 1 with hinged bolts 2, a movable formwork 3, a cover 4 and a bottom 5. The cover 4, made in the form of a traverse, and the bottom 5 are provided with elastic elements made in the form of an upper rubber seal 6 and a lower rubber seal 7. To the upper rubber seal 6 are fixed elastic hemispheres 8 having a cutout for installing mounting elements 9. The mold is equipped with a lateral mechanism compression, which is installed inside the power frame 1 and made in the form of paired rails 10 having oval grooves, which include spacers 11, forming an articulation of the power frame 1 with the formwork 3, which, in turn, is equipped with rails 12 having oval voids for spacer installation 11.

The inner space of the formwork 3 forms a cavity 13 for placement in it of a concrete mixture and molding products. Moreover, on the side surface of the formwork 3 installed elastic liners 14.

A method of manufacturing products under pressure from high strength fiber-reinforced concrete is as follows.

Before laying in the mold, the concrete mixture for the manufacture of products is filled with fiber fibers metal or non-metal, whereby fiber concrete is obtained. These fibers play the role of reinforcement, which is used to increase the strength of concrete mortar. The structure of the resulting concrete mixture - fiber-reinforced concrete - is a homogeneous structure, which is penetrated from all sides by fibers from various materials. It is they (fibers) that determine the technical characteristics of concrete, create the effect of reinforcement.

There are two groups of fiber:

- metal - the starting material is steel, which has a different shape and size;

- non-metallic - made from materials such as glass, acrylic, cotton, basalt, polyethylene, carbon, carbohydrate and others.

Steel fiber is the most common filler. It has increased resistance to stress, does not shrink and does not form cracks during service. Its most remarkable qualities are its long service life, density and wear resistance. In addition, fiber-reinforced concrete with steel filler does not lose its properties under the influence of low temperatures, moisture and fire.

There are some advantages of the obtained fiber-reinforced concrete:

- reduction of construction costs when using fiber fibers for reinforcement instead of a reinforcing mesh or frame;

- concrete consumption with the use of fiber fibers is much less;

- unlike other types of concrete, fiber-reinforced concrete does not lose its technical characteristics even after the end of its service life, because thanks to the fibers of the fiber, the material becomes viscous;

- etc.

There is only one drawback of such concrete, namely the high cost, when compared with ordinary concrete mortar. However, this drawback is easily compensated by the durability of the building material and its resistance to wear.

Due to the above characteristics of fiber-reinforced concrete, it is used in constructions that are under strong environmental pressure. These designs can be both industrial and domestic in nature.

After preparation, thus, of the concrete mixture - fiber concrete for the manufacture of products in the cavity 13 of the formwork 3 of the prepared mold, install (if necessary) reinforcement and lay the concrete mixture - fiber concrete. Then, a cover 4 with mounting elements 9 is installed and a force is applied to the cover 4 using a press. In this case, the elements of the movable formwork 3 are moved relative to the power frame 1, the spacers 11 are rotated and elastic inserts 14 are crushed and the concrete mixture is compressed. The concrete mix placed in the mold is kept in it under pressure of at least 2.5 MPa until the formwork strength is set, but not less than 240 min, thereby compacting it and squeezing excess moisture from the concrete outside the mold. When the necessary concrete compaction is achieved, cover 4 is fixed to the power frame with the aid of hinged bolts 2.

The hardening fiber-reinforced concrete mixture is heated under pressure to a temperature of not more than 80 ° C by supplying the coolant inside the mold cavity, and the temperature of the coolant for heating the molded products should not exceed 95 ° C, and the rate of temperature increase should not exceed 35 ° C per hour. The optimal mode, satisfying the necessary pace of production of products, is the heating of concrete to 80 ° C with a rise time of 240 minutes. At a higher temperature, moisture evaporates intensively, which adversely affects the quality of manufactured products.

After the concrete has set the appropriate strength, the folding bolts 2 are untwisted, the product is released from excess pressure and the cover 4 is removed from the power frame 1. At the same time, the elastic liners 14 unclench the elements of the movable formwork 3, as a result of which a formwork gap is formed and the product is removed from the formwork 3 and press forms.

The design solution of the proposed mold allows you to create a volumetric compression of the concrete mixture as a result of the translational movement of the movable formwork 3 relative to the power frame 1 with an increase in the proportion of lateral compression at the end of pressing with the use of rotating struts 11. The ratio of lateral compression and longitudinal force is regulated in advance by setting a certain inclination of the struts 11. In contrast to the known solutions, where the creation of lateral force on the mixture is provided either by using a hydraulic chamber, or and with the help of the wedge effect, the constructive solution of the proposed equipment is more economical, technologically advanced and improves the quality of the product.

A similar method of manufacturing products from fiber-reinforced concrete under pressure is less energy-consuming, allows you to increase the turnover of the tooling kit, increases productivity in the manufacture of products, their quality and strength characteristics. Products made of high-strength concrete (in our case, fiber-reinforced concrete), can significantly reduce the size of the cross-sections of structures. They are relatively lightweight, transportable, and therefore reduce overall construction costs.

Using the proposed technical solution allowed us to improve the operational characteristics of the products, create a technological process that allows to reduce the consumption of reinforcing bars, to reduce not only the cost, but also to reduce the complexity and terms of the work due to the technical process under pressure and the addition of fiber fibers to the concrete mixture. One of the most common additives for the production of fiber-reinforced concrete products are basalt and fiberglass, small fractions of metal, synthetic fibers. Therefore, fiber-reinforced concrete is pre-reinforced, which increases the strength of products and structures manufactured with its use, and also allows to reduce the consumption of reinforcement by 20%, which not only reduces the cost, but also reduces the complexity and timing of work. Fiber fibers used in the prepared concrete mixture play the role of reinforcement, which is used to increase strength and reduce shrinkage deformation of the concrete mixture. They determine the technical characteristics of concrete, create the effect of reinforcement. The use of concrete reinforcement with fibers is an economical approach that minimizes the plastic formation of shrinkage cracks, reduces thermal cracking and increases the wear resistance of concrete, and the technological process of manufacturing products under pressure created in the closed mold volume in compliance with the temperature regime significantly increases the strength characteristics of the product.

Claims (1)

A method of manufacturing products under pressure from high-strength fiber-reinforced concrete, according to which reinforcement is placed in the mold cavity (if necessary) and the concrete mixture is laid, then the mold is closed and pressure is created inside the mold by means of the press, whereby the concrete mixture is squeezed, after a set of concrete strength, the product is freed from excess pressure and removed from the mold, characterized in that the concrete mixture for the manufacture of products before filling it into the mold is filled with fiber metal or non-metallic, whereby fiber-reinforced concrete is obtained, the concrete mixture placed in the mold is held in it under pressure at least 2.5 MPa until the stripping strength is set, but not less than 240 minutes, and the hardening concrete mixture is heated to a temperature of not more than 80 ° C due to the supply of coolant inside the cavity of the mold, and the temperature of the coolant for heating the molded products should not exceed 95 ° C, and the rate of temperature increase should not exceed 35 ° C per hour.

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