SU1426798A1 - Method of compacting concrete mix - Google Patents

Abstract

This invention relates to the building materials industry. The purpose of the invention is to improve the quality of compaction and reduce energy consumption. The concrete mixture laid in the mold is compacted by vibropressing. Static and vibration force actions are carried out through the wedge forming element — horizontally directed vibrations are applied to the end face of the element. Moreover, perpendicular oscillations are additionally applied to the wedge element. 1 hp f-ly, 3 ill.

Description

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I The invention relates to the industry of building materials and can be used in the compaction of predominantly hard concrete mixtures.

The purpose of the invention is to improve the quality of compaction and reduce energy consumption. FIG. 1 shows a device for compacting a concrete mixture of a moldable; in a horizontal position a flat one: -, vertical section; in fig. 2 -: a device for compacting a concrete mix of two flat products being simultaneously formed in a vertical position, a horizontal section; in fig. 3 shows a device for compacting a concrete mix of a flat product being formed in a vertical position, a vertical section.

The device (Fig. 1) consists of a concrete mix 2, installed on the basis of a form 1 with a side-rig, in which a concrete mixture 2 is laid. Along the side of the rig there is an elastic rubber sheet 3. On the surface of the concrete mix 2 there is a wedge-forming element 4 above which The fixed supports 5 are located. The device is also equipped with a vibrating unit 6 installed in the guides 7, with the hydraulic actuator 8 moving it. The vibration block 6 is located on the side of the thorn of the wedge forming element, opposite to its acute angle.

The device (Fig. 2) consists of two shuttering walls 10 fixed on a pallet 9, fitted with a side rig, along which a flexible rubber sheet 11 is installed. Between the shuttering walls 10 a wedge shaping element 12 is installed, in the cavity between which and the walls 10 a concrete mix 13 is laid The angle between the planes of the walls 10 corresponds to the angle between the planes of the wedge forming element 12. The device is equipped with a vibroblock 14 mounted in the guides 15 and a hydraulic actuator 16 for moving the vibroblock 14.

The device (Fig. 3) consists of a shock-vibration platform 17 with a wedge frame 18 rigidly fixed on it, in the opening of which a mold with a concrete mixture 19 is installed, consisting of the lower 20 and end 21 sheets, as well as movable side walls 22. On the outer surface of the walls 22 are fixed rods 23, passed through slit slots in the end walls 21. This allows limited movement of the walls 22. On the outer side, wedge elements 24 are also attached to the walls 22, which are in contact with the internal inclined surfaces wedge frame wedge 18.

The vibration direction of the vibrating organs in FIG. 1-3 is indicated by arrows.

The method of compacting the concrete mixture is carried out as follows.

Concrete mix 2, 13, 19 is placed into the molding cavity, after which the vibratory blocks 6 and 14 are moved to contact with the end face of the wedge element 4 and 12, and in the device (Fig. 3) the mold is installed in the opening of the wedge frame 18 associated with 17. The devices excite oscillations, and in devices (Figs. 1 and 2) they also activate hydraulic actuators 8 and 16, after which the wedge forming element begins to move under the action of vibration pulses and static force action in the direction of parallel to its forming plane awes

In the device (Fig. 3), static force is created by the force of the weight of the mold with the concrete mix. When the forming element is moved to the cement-free mixture 2, 13, 19, the static pressure starts to be transmitted, which results in its compaction by moving the wedge forming element 4, 12, 24 in the direction parallel to its forming plane.

If necessary, internal vibrators of wedge elements 4 and 12 or mounted vibrators on the outer side of walls 22 (not shown) that vibrate mobile forming elements, 12, 24 in the direction perpendicular to their mid-plane, are simultaneously included.

Compaction is continued until the movement of the wedge forming elements is recorded, after which the vibration exciter is turned off, and the wedge element is removed, for example, using hydropushers. For the device (Fig. 3), using a bridge crane, the form with compacted concrete mix is removed from the wedge frame 18. 0 When dismounting, the wedge forming element is removed from the concrete mix along a sliding path, which prevents the "suction" effect and does not lead to - g structural effects in the concrete mix.

Example. The concrete mix is compacted by two simultaneously molded products — slabs with a size of 0.3X0.5 m and a thickness of 0.1 m. The concrete mix of composition 1: 3.1: 4.8 on portland cement M400 with a stiffness according to technical viscometer 150 into a double vertical form (Fig. 2) with an angle of 5 ° between the planes of the wedge forming element. At the end of the wedge forming element, oscillations with a frequency of 5,160 Hz are transmitted. In this case, the amplitude of oscillation. forming element in the direction parallel to its forming plane (horizontally directed oscillations)

is 0.1 mm. Such fluctuations on the wedge element reduce to almost zero the value of the coefficient of friction.

With a force on the end of the forming element 5 kN, the pressure on the concrete mix is 0.35 MPa. Compaction is carried out for 2 minutes. The npoi HOCTH limit for compressing samples at 28 days of age is 34.5 MPa.

Removing the wedge forming element is carried out immediately after the completion of compaction. The high quality of the concrete surface is ensured even when the surface of the forming element is not lubricated.

For comparison, the concrete mixture is compacted by two plates that are simultaneously molded in a horizontal position during the transfer of a force action to a punch in the direction perpendicular to its mid-plane. The impact of a force of 5 kN for 2 minutes, providing a pressure on the concrete mixture of 0.017 MPa, allows a strength of 24.6 MPa to be reached in 28 days of age. To achieve a pressure of 0.35 MPa on the concrete mix, the static force on the punch is increased to 103 kN. In this case, the tensile strength of the samples is 0

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lt is 30.8 MPa. When the punch is removed immediately after the end of compaction, tearing of the concrete mix is observed, which reduces the quality of the concrete surface.

With high demands on the quality of compaction of the concrete mix, an additional vibration effect perpendicular to its mid-plane is poured onto the moving wedge forming element.

The vibration impact of a frequency of 160 Hz with an amplitude of 0.05 mm makes it possible to increase the ultimate compressive strength from 34.5 to 38.6 MPa.

Claims (2)

1. A method of compacting a concrete mix by vibropressing, characterized in that, in order to increase the quality of compaction and reduce energy consumption, vibropressing is carried out with a wedge shaping element with horizontal vibrations applied to its end face. 2. A method according to claim 1, characterized in that the wedge forming element is additionally affected by vibrations directed perpendicularly to its mid-plane. //////  - x / / / X YU Y ///// A u /) (////  I 1 FIG. one 12 5 / sixteen FIG. 2 18 11 Fi & .З