RU2652770C1 - Permanent steel fiber reinforced concrete formwork - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to construction, in particular to permanent formwork, and can be used as a structural element for the main parts of buildings and structures, such as walls, columns, floors, roofs, foundations, etc. In this case, the invention can be used for the erection of cast concrete and reinforced concrete structures in industrial, civil, power engineering and other industries. Fixed steel fiber reinforced concrete formwork contains flat sheets, connected together by fastening elements, while flat sheets are made of a self-sealing steel fiber reinforced concrete mixture of high-strength cements of not less than 500 grade, highly disperse active mineral additive, hyperplasticizer and fibers of steel fiber. Height of laying of a self-sealing concrete mix in the formwork is up to 4,000 mm, the thickness of sheets of permanent formwork is min 10 mm, and fasteners are installed with pitch of up to 1,500 mm.

EFFECT: invention makes it possible to increase the strength, stiffness, reliability, durability of the permanent formwork, improve its adhesion to concrete, simplify the formwork structure, reduce its material-consumption, increase the adaptability of construction and installation works, and shorten construction time.

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Description

FIELD OF THE INVENTION

The invention relates to the field of construction, in particular to fixed formwork, and can be used as a structural element for the main parts of buildings and structures, such as walls, columns, ceilings, coatings, foundations, etc. Moreover, the invention can be used for the construction of monolithic concrete and reinforced concrete structures in industrial, civil, energy construction and other industries.

State of the art

From the existing level of technology it is known to use for the manufacture of fixed formwork a number of materials:

wood (see [1] patent RU 2380497, IPC E04B2 / 86, publ. 01/27/2010; [2] patent RU 2267584, IPC E04B2 / 86, publ. 10.01.2006) and arbolite, arbosolite concrete and xylolite made on its basis (see [3] patent SU 1559074, IPC E04G9 / 10, publ. 04/23/1990), cement-fiber boards (see [4] patent SU 586797, IPC E04B2 / 28, publ. 07.11.1980);

phosphogypsum (see [5] patent SU 1716044, IPC E04G9 / 10, publ. 02.28.1992);

polymers (see [6] patent RU 2107132, IPC E04B1 / 38, publ. 03.20.1998; [7] RU 2338847, IPC E04B2 / 86, publ. 20.11.2008; [8] RU 2225922, IPC E04B1 / 00, E04B2 / 00, published on March 20, 2004; [9] RU 2267584, IPC E04B1 / 38, E04D19 / 00, published on January 10, 2006; [10] RU 2253719, IPC E04G21 / 26, published on 10.06.2005; [11 ] RU 2220264, IPC E04B2 / 00, published on December 27, 2003);

carbon plastics (see [12] patent RU 2392394, IPC E04B2 / 86, publ. 06/20/2010);

metal (see [13] patent RU 2388881, IPC E04G11 / 02, publ. 05/10/2010; [14] RU 2225921, IPC E04B1 / 16, E04B2 / 84, E04B2 / 86, publ. 20.03.2004).

The main disadvantages of formwork using wood and polymers are their low strength and rigidity, as well as poor adhesion to concrete, which requires the installation of fasteners with a pitch of 200 mm. Formwork made of carbon fiber and metal, which has significantly greater strength than wood and polymers, but lacks adhesion to concrete and stiffness, also requires the installation of fasteners with a pitch of 200 mm, which complicates the process of laying concrete when concreting structures. In addition, the formwork of these materials seriously complicates or eliminates (non-removable metal formwork) operational non-destructive ultrasonic quality control of laying concrete.

A closer solution is the use of fixed formwork made of reinforced concrete (including prestressed) (see [14] SU 1017046, IPC E04C2 / 26, E04C2 / 04, E04C2 / 08, E04C2 / 10., Publ. 07.11.1989; [15] SU 1528875, IPC E04C2 / 26, published on December 15, 1989, [16] SU 1534156, IPC E04B2 / 28, E04G11 / 00, published on 01/07/1990). The main disadvantage of this type of fixed formwork is the need to use bar and / or wire reinforcement (including prestressed) for its manufacture, as well as the significant thickness of the formwork panels (at least 70 mm, as a rule, 100 mm) and, accordingly, big dead weight.

Closest to the claimed technical solution is the use of formwork made of:

reinforced cement (see [17] patent SU 1544931, IPC E04C9 / 10, 02.23.1990, [18] SU 1199890, IPC E04G9 / 10, publ. 12/23/1985), which is a prototype of steel fiber concrete, but less technological in manufacturing and requiring application wire reinforcement;

steel-fiber concrete in the form of slabs with ribs increasing the strength of the slab (see [18]), or slabs with an anchor layer, to increase adhesion with concrete laid in the formwork (see [19] patent SU 1728432, IPC E04G9 / 10, 1992).

Despite the good adhesion of steel fiber reinforced concrete and reinforced cement formwork with concrete, the disadvantage of this solution is that until the beginning of the present century, cement and cement-sand matrix of class not higher than B35 were used for the manufacture of reinforced cement and steel fiber concrete with a water-cement ratio of 0.4-0.5, and for fiber - steel with a tensile strength not higher than 1500 MPa. Therefore, to ensure the given strength and stiffness of the sheets (panels) of the formwork, it was necessary to perform them ribbed, which significantly complicated the manufacturing technology, and to protect the reinforcement from corrosion, increase their thickness and, consequently, increase weight. In addition, the concrete mix manufacturing technology used at that time did not allow obtaining products with low porosity (less than 4-5%) and, accordingly, high strength (no more than B60), frost resistance (no more than F300), waterproof (no more than W8) and with an indicator of surface quality 2-Ш, which requires puttying before applying the paintwork.

The prior art plate fixed formwork (see [20] RF patent No. 167851, IPC E04G11 / 06, publ. 20.01.2017), consisting of a cement composite reinforced with non-metallic fiber fibers, while it is equipped with a reinforcing frame made of composite non-metallic mesh.

The prior art composition for the manufacture of thin (10-20 mm thick) plates of fixed formwork (see [21] RF patent No. 2323318, publ. 04/27/2008) containing information about the formulation of a mixture based on a mineral binder - Portland cement with the addition of an antiseptic and osprey or basalt fiber as a fibrous filler. Also in this patent, options for manufacturing plates of the specified composition are indicated to obtain the claimed strength characteristics (compressive strength: from 7 to 16.3 MPa; tensile from 12.3 to 21 MPa): by pressing under pressure up to 10,000 kG / cm ² or heating to 110 ° C.

The proposed composition and manufacturing technology of fixed formwork slabs are not sufficiently technological, since they suggest the creation of a specialized production line, while the option of introducing new technologies into existing and functioning technological lines for the production of concrete and reinforced concrete products with minimal costs is currently quite relevant. refitting.

The closest analogue in technical essence to the claimed invention is a fixed formwork (see [22] RF patent No. 1629435, IPC E04G9 / 10, publ. 23.02.1991) containing flat formwork plates, embedded parts, screeds, while the plates are made of steel fiber concrete and are held at a predetermined distance using screeds.

The disadvantage of the prototype is the weak rigidity of the structures, insufficient adhesion with concrete, the complex process of laying concrete, as well as the complexity of quality control of laying monolithic concrete.

SUMMARY OF THE INVENTION

The objective of the claimed invention is to reduce to a minimum the thickness of the sheets of fixed formwork, a significant increase in their static and dynamic strength, crack resistance, frost resistance and water resistance to grades, respectively, not lower than F1000 and W24, achieving surface quality not worse than 3-W.

The technical result is to increase the strength, rigidity, reliability, durability of fixed formwork, improve its adhesion to concrete, simplify the formwork design, reduce its material consumption, increase the manufacturability of construction and installation works, reduce construction time.

The problem is solved, and the technical result is achieved due to the non-removable steel-fiber-reinforced concrete formwork containing flat sheets interconnected by fasteners, while the flat sheets are made of a self-compacting steel-fiber concrete mixture of high-strength cements of at least 500 grade, a highly dispersed active mineral additive, hyperplasticizer and steel fibers .

Also, the technical result is achieved due to the fact that the height of laying in the formwork of the self-compacting concrete mixture is up to 4000 mm; the thickness of the sheets of fixed formwork is from 10 mm; fasteners are installed in increments of 600 to 1,500 mm.

The implementation of the invention

Steel-fiber-reinforced concrete fixed formwork consists of flat sheets without ribs, which are made on the basis of modern self-compacting fine-grained steel-fiber concrete mixtures using high-strength cements of at least 500 grade, highly dispersed active mineral additives based on silica fume, fly ash or ground granulated sulfonate sulphate, granular sulfonated sulphonates and fibers of profiled steel fiber. This makes it possible to reduce the water-cement ratio to 0.26 and obtain axial compression strength corresponding to particularly high-strength class concrete with a compressive strength of not lower than B80, axial tensile strength of not lower than Bt7, and tensile strength in bending of not lower than Rtf25 with a porosity of not more than 2.6%. Flat sheets of fixed formwork are interconnected by means of fasteners.

Such characteristics of the material of fixed formwork allow you to: use flat (without ribs) sheets of fixed formwork with a thickness of 10 mm or more, install their fastening elements in increments of 600 to 1500 mm, which makes it possible to concrete structures with self-compacting concrete mixtures with a stacking layer height of up to 4000 mm. At the same time, the formwork, which has the same acoustic characteristics as concrete, allows real-time ultrasonic monitoring of the quality of laying concrete mix (see, for example, [23] patent RU 2572103, IPC GO1N29 / 07, E04G 9/10, publ. 27.12 .2015), including - determination of its level and degree of compaction. In addition, the surface quality of the formwork allows you to apply paintwork on it without puttying.

Example.

To test the applicability of the proposed solution, test fragments of wall reinforcing blocks and overlapping of the reactor compartment of the VVER-TOI NPP with sheets of fixed steel-fiber concrete formwork 30 mm thick, up to 2000 mm long and 3600 mm high were made and concreted. The formwork was made on the basis of self-compacting fine-grained concrete of class B80, reinforced with steel fibers with a diameter of 0.3 mm and a length of 15 mm with a reinforcement of 3% in volume. When concreting the reinforcement formwork block, a self-compacting concrete mixture was laid in it with a layer 3200 mm high. The quality of laying the concrete mixture was controlled using ultrasound with through sounding.

Hyperplasticizers and finely dispersed active mineral additives ensure the immiscibility of the fine-grained steel-fiber concrete mixture and a low water-cement ratio. As a result, the matrix of steel fiber reinforced concrete acquires high compressive strength, high adhesion to fiber and cast concrete, high frost resistance and water resistance.

The introduction of thin, high-strength profiled fiber provides an increase in the strength of steel fiber reinforced concrete for axial tensile and bending tensile, impact resistance and crack resistance of steel fiber-reinforced concrete formwork, contributes to increased durability.

The installation of fastening elements for flat sheets with a pitch of more than 600 mm does not increase the reinforcement density and ensures the free placement of concrete mixture in the structure, eliminates its hovering, segregation and under-compaction, allows free lowering of the concrete pump trunk into the interdeck space.

Claims (4)

1. Non-removable steel-fiber-reinforced concrete formwork containing flat sheets interconnected by fasteners, characterized in that the flat sheets are made of a self-compacting steel-fiber concrete mixture of high strength cements of at least 500 grade, a highly dispersed active mineral additive, hyperplasticizer and steel fiber fibers. 2. Non-removable steel-fiber concrete formwork according to claim 1, characterized in that the stacking height of the self-compacting concrete mixture in the formwork is up to 4000 mm. 3. Fixed steel-fiber concrete formwork according to claim 1, characterized in that the thickness of the sheets of fixed formwork is from 10 mm. 4. Fixed steel-fiber concrete formwork according to claim 1, characterized in that the fasteners are installed in increments of 600 to 1500 mm.