SU1276950A1 - Device for shear test of concrete - Google Patents

Abstract

The invention relates to the construction of concrete structures and is intended to measure the strength characteristics of concrete. The invention makes it possible to bring the test conditions of a concrete sample (OB) to a real one by providing the possibility of shear testing in Building II, taking into account the stress state of the latter. To do this, on two opposite walls of the sample box, movable walls 5 and 6 are installed to form slotted pressure 3 and compensatory 4 chambers rigidly interconnected by thrust rods 7. In chamber 3 connected to the load device as a pressure source, the pressure of the working medium and bring it to the shear OB 10, located in the bottomless rectangular box 1. The shift occurs along the planes passing at the levels of the lower and upper edges of the walls 5 and 6. On the other two walls of the box 1 ntiadgezionnoe coating. The rods 7 allow the OB 10 to work together throughout S with the volume without distortion from the local compression OB 10. When the OB 10 is shifted, it is shifted (L is placed towards the chamber 4. Its connection with the atmosphere eliminates the possibility of air being trapped in it; test results. By knowing the pressure of the working medium in the chamber 3 and the area of its wall 5, as well as the dimensions of OB 10, determine the magnitude of the resistance of the OB 10 to shear. 2 Il.

Description

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The invention relates to the construction of concrete structures.;. These parameters measure the npvOMHoc / rHbix characteristics of concrete.

The purpose of the invention is to bring the test conditions closer to reality by allowing the concrete to be tested for shear in the structure, taking into account the stress state of the latter.

Figure 1 presents the proposed device, a General view; figure 2 - section aa in figure 1.

Concrete Testing Device

the shift comprises a housing made in the form of a rectangular duct 1 (for example, from steel). A layer of anti-adhesive material 2 (for example, polyethylene sheets 2o are glued on the inner side of the box 1 on two opposite walls). On the other two: the walls opposite each other are attached to the slit pressure chamber 3 and the slit compensation chamber A, provided with movable walls 5 and 6, respectively, 25 connected to each other by retaining rods 7 of a periodic profile.

A nozzle (pipe) 8 is connected to the chamber 3 for connection to the pressure source Q (not shown), and a nozzle (pipe) 9 to the chamber 4 for connection with the atmosphere.

The device works as follows.

Before concreting the structure I1, the box 1 is fixed in the block of concreting to the formwork or reinforcement (not shown) and connected to the pipes 8 and 9 of the tube (not shown), 40

united respectively with the source of pressure of the working medium (not shown) and with the future cavity of the cementing or drainage waste of the dam or the free end of any other structure (not shown).

Then the structure 11 is concreted. In this case, the cavity of the device box 1 is filled with a concrete mixture, forming test sample 10 of concrete in it.

Upon reaching the concrete structure of a given age, the concrete sample 10 is tested for shear. To do this, in the pressure slit chamber 3 they create pressure of the working medium (for example, oil) from the source of pressure

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nor, located outside

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Q

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or in a lost structure, and bring this pressure to a shift of the sample 10 of concrete along the planes passing at the levels of the lower and upper edges of the movable machine 5 and 6 of the pressure chamber 3 and the compensation chamber 4. When the sample 10 is shifted, the latter moves towards compensation chamber 4. The connection of the cavity of this chamber with the atmosphere eliminates the possibility of air entrapment in the compensation chamber and does not distort the test results. The presence of stop rods 7 enables the sample 10 to work together throughout its volume without manifesting distortion from local compression of the concrete.

By knowing the pressure of the working medium in the pressure chamber 3 and the area of its moving wall 5, as well as the dimensions of the cutting surfaces of the concrete sample 10, the amount of resistance of the concrete to shear is determined.

The connection of sample 10 of concrete with concrete of structure 1I provides the same conditions for the hardening of sample 10 of concrete and obtaining characteristics similar to those for concrete of structure 11, taking into account the stress state of the load 1 I.

Claims (1)

This invention relates to the construction of concrete structures.;. These parameters measure the npvOMHoc / rHbix characteristics of concrete. The purpose of the invention is to bring the test conditions closer to reality by allowing the test of concrete shear on the structure with regard to the stress state of the latter. Figure 1 presents the proposed device, a General view; in Fig.2 a section aa in Fig.1. A device for testing concrete in shear comprises a housing made in the form of a rectangular duct 1 (for example, of steel). A layer of anti-adhesive material 2 (for example, a sheet of polyethylene is glued on the inner side of the box 1 on two opposite walls). On the other two: the walls opposite each other are attached to the slit pressure chamber 3 and the slit compensation chamber A, provided with movable walls 5 and 6, respectively, connected to each other by retaining rods 7 of a periodic profile. A nozzle (pipe) 8 is connected to the chamber 3 for connection to a pressure source of a working medium (not shown), and a nozzle (pipe) 9 for connection with the atmosphere is connected to the chamber 4. The device works as follows. Before concreting, structure I box 1 is fixed in a concrete block to the formwork or reinforcement (not shown) and connected to the nozzles 8 and 9 of the tube (not shown), connected respectively to the source of pressure of the working medium (not shown) and to the future cavity of the cement or the drainage of the dam or the unencumbered face of any other structure (not shown). Then the structure 11 is concreted. In this case, the cavity of the device box 1 is filled with a concrete mixture, thus forming the test sample 10 of concrete. Upon reaching the concrete structure of a given age, the concrete sample 10 is tested for shear. To do this, in the pressure slit chamber 3 a pressure of the working medium (e.g., oil) from a pressure source located outside the weapon or in the lost structure is brought, this pressure is brought to shift of the concrete sample 10 along the planes passing through the lower and the upper rails of the movable machine 5 and 6 with the pressure of the chamber 3 and the compensation chamber 4. When the sample is shifted 10, the latter moves towards the compensation chamber 4. The connection of the cavity of this chamber with the atmosphere eliminates the possibility of air entrapment in the compensation chamber and not distortion Performan t test. The presence of thrust rods 7 ensures the joint operation of sample 10 of concrete throughout its volume without manifesting distortion from local compression of concrete. By knowing the pressure of the working medium in the pressure chamber 3 and the area of its moving wall 5, as well as the dimensions of the cutting surfaces of the concrete sample 10, the amount of resistance of the concrete to shear is determined. The connection of sample 10 of concrete with concrete of structure 1I provides the same conditions for the hardening of sample 10 of concrete and obtaining characteristics similar to those for concrete of structure 11, taking into account the stress state of the load 1 I. Claim device for shearing concrete, comprising a housing for placing a sample and load device, characterized in that, in order to bring the test conditions closer to the real one by allowing the concrete to be tested for shear in the structure, taking into account the stress state of the latter, movable walls, the casing is made in the form of a bottomless rectangular box, on two opposite walls of which an anti-adhesive coating is applied, and on the other two movable walls are installed and to form a discharge gap and the compensation chambers are rigidly interconnected thrust rods, a loading device is designed as a pressure source associated with the pressure chamber, the compensation chamber is connected with the atmosphere.