CN104534972A - Ultra-low-temperature concrete strain measurement testing device - Google Patents

Abstract

The invention discloses a concrete strain measurement test device under ultra-low temperature. The ultra-low temperature environment chamber is composed of a top plate, a bottom plate, a front plate, a rear plate, a left side plate and a right side plate. The right side plate can be opened; Hole A and hole C, hole B and hole D are correspondingly arranged on the board, and quartz rod A and quartz rod B are arranged between the left and right holes; a dial gauge is arranged between the quartz rods on the left and right side plates A and dial indicator B; there are holes E and holes F in the center of the top plate and the bottom plate respectively, the steel rod A passes through the hole E through the steel backing plate A, and the steel rod B passes through the hole F through the steel backing plate B The test piece is loaded with external force; a liquid nitrogen inlet and a liquid nitrogen outlet are arranged on the left side of the lower part of the front plate and the right side of the upper part of the rear plate. The invention has simple structure and convenient operation, and realizes the strain measurement of the concrete specimen under the environment of general low temperature and ultra-low temperature (lower than -80°C).

Description

Concrete strain measurement test device at ultra-low temperature

technical field

The invention relates to a building structure test device, in particular to a test device for measuring concrete strain at ultra-low temperature.

Background technique

In the design of building structures, it is often necessary to study the performance of concrete at low or even ultra-low temperatures to provide a basis for design, and it is often essential to measure the strain of concrete at low temperatures. Some studies require loading of concrete specimens when measuring strain, while others do not, such as measuring concrete creep. At present, most of the existing methods and devices for measuring the strain of concrete structures in low temperature environments are aimed at normal temperature environments. The working conditions of measuring devices in low temperature environments are very unstable, and some may even fail, resulting in the failure of normal test.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned shortcomings that the prior art cannot be adapted to concrete strain measurement under low temperature environment, and to provide a test device for concrete strain measurement under ultra-low temperature for the requirement of having or not loading.

The present invention is realized through the following technical solutions.

A concrete strain measurement test device at ultra-low temperature, comprising an ultra-low temperature environment box and a measuring device, characterized in that the ultra-low temperature environment box consists of a top plate 1, a bottom plate 2, a front plate 3, a rear plate 4, a left side plate 5 and a right side plate 6 components, the right side plate 6 is a movable, openable side plate, in order to place and take out the test piece;

The central symmetrical positions of the left side plate 5 and the right side plate 6 are respectively provided with a circular hole A7, a hole B8, a hole C9 and a hole D10; the hole A7 corresponds to the hole C9, the hole B8 corresponds to the hole D10 on the left and right, and the holes are respectively set in the middle. There are quartz rod A15 and quartz rod B16, both of which are pre-cast in the concrete specimen; a dial gauge A17 is set between the upper and lower quartz rods on the side of the left plate 5, and a dial gauge A17 is set on the right plate 6 A dial gauge B18 is set between the upper and lower quartz rods on one side; the two quartz rods and the two dial gauges form a strain extraction measurement device;

A circular hole E11 and a hole F12 are respectively arranged at the center of the top plate 1 and the bottom plate 2, and a steel backing plate A19 and a steel rod A20 are arranged between the hole E11 and the upper surface of the test piece 23, and the steel rod A20 passes through In the hole E11, a steel backing plate B21 and a steel rod B22 are arranged between the hole F12 and the lower surface of the test piece 23, and the steel bar B22 passes through the hole F12; the external force is applied to the test piece 23 through the steel rod A20 and the steel bar B22;

A liquid nitrogen inlet 13 is provided on the lower left side of the front panel 3, and a liquid nitrogen outlet 14 is provided on the upper right side of the rear panel 4 for charging and discharging liquid nitrogen;

The top plate 1, the bottom plate 2, the front plate 3, the rear plate 4, the left side plate 5 and the right side plate 6 are all made of polyurethane foam boards.

The top plate 1, the bottom plate 2, the front plate 3, the rear plate 4 and the left side plate 5 are bonded with low temperature resistant adhesive.

The gap between the quartz rod A15 and the quartz rod B16 and the hole A7, the hole B8, the hole C9 and the hole D10 is filled with a low-temperature covering glue; the width of each of the above-mentioned apertures is slightly larger than the diameter of the quartz rod, and the upper edge of the aperture is higher than The upper edge of the quartz rod is 4-5mm, and the lower edge of the aperture is 4-5mm lower than the lower edge of the quartz rod.

The height of the ultra-low temperature environment chamber is 600-700, the width is 400-500, and the depth is 400-500.

The ultra-low temperature concrete strain measurement test device of the present invention is simple in structure and easy to operate, and is applicable to the strain measurement of concrete at low temperature and ultra-low temperature with or without loading, provides a constant temperature environment for the test, and realizes general low temperature and ultra-low temperature ( Strain measurement of concrete specimens in environments below -80°C).

Description of drawings

Fig. 1 is the structural representation of the ultra-low temperature environment box of test device of the present invention;

Fig. 2 is a partially enlarged schematic view of hole A, hole B, hole C and hole D;

1-1 sectional view of Fig. 1 of Fig. 3;

Fig. 4 is a 2-2 sectional view of Fig. 1,

Fig. 5 is a sectional view of the test device 2-2 in Fig. 1 when no loading is required.

The reference signs of the present invention are as follows:

1———Top plate 2———Bottom plate

3——front plate 4——rear plate

5——Left panel 6——Right panel

7——Hole A 8——Hole B

9——hole C 10——hole D

11——hole E 12——hole F

13——Liquid Nitrogen Import 14——Liquid Nitrogen Export

15——Quartz Rod A 16——Quartz Rod B

17——Dial gauge A 18———Dial gauge B

19——Steel backing plate A 20——Steel rod A

21——Steel backing plate B 22——Steel rod B

23——Test piece 24——Foam plug A

25——foam plug B

Detailed ways;

The present invention will be further described below in conjunction with accompanying drawing.

Referring to Fig. 1, Fig. 3, Fig. 4, the ultra-low temperature environment box of the present invention is made up of top plate 1, base plate 2, front plate 3, rear plate 4, left side plate 5 and right side plate 6, and right side plate 6 is a movable, The side panels can be opened to facilitate the placement and removal of test pieces; the top panel 1, bottom panel 2, front panel 3, rear panel 4, left panel 5 and right panel 6 are all made of polyurethane foam; the top panel 1 , base plate 2, front plate 3, rear plate 4 and left side plate 5 all adopt low-temperature-resistant bonding glue to bond.

The central symmetrical positions of the left side plate 5 and the right side plate 6 are respectively provided with a circular hole A7, a hole B8, a hole C9 and a hole D10; the hole A7 corresponds to the hole C9, the hole B8 corresponds to the hole D10 on the left and right, and the holes are respectively set in the middle. There are quartz rod A15 and quartz rod B16, a dial gauge A17 is set between the upper and lower quartz rods on the left side of the plate 5, and a dial gauge B18 is set between the upper and lower quartz rods on the right side of the plate 6 ; Two quartz rods and two thousand gauges form a strain-leading measuring device.

Before the test, the test piece 23 is put into the ultra-low temperature environment box from the side of the right side plate 6, and the test piece is fixed.

A square hole E11 and a hole F12 are respectively arranged at the center of the top plate 1 and the bottom plate 2, and a steel backing plate A19 and a steel rod A20 are arranged between the hole E11 and the upper surface of the test piece, and the steel rod A20 passes through the hole E11 ;A steel backing plate B21 and a steel rod B22 are arranged between the hole F12 and the lower surface of the specimen, and the steel rod B22 passes through the hole F12; the external force is applied to the specimen through the steel rod A20 and the steel rod B22 to measure the concrete strain .

Quartz rod A15 and quartz rod B16 are placed in the specified position of the section to be tested in advance when making the concrete specimen, and then the concrete of the test member is poured, and the quartz rod A15 and quartz rod B16 are poured into the concrete specimen , making it a whole. Since the coefficient of linear expansion of quartz is very small, the amount of deformation due to the effect of temperature is negligible. The gap between quartz rod A15 and quartz rod B16 and hole A7, hole B8, hole C9 and hole D10 is filled with low-temperature covering glue, see Figure 2; the width of each of the above-mentioned apertures is slightly larger than the diameter of the quartz rod, and the upper edge of the aperture is high The upper edge of the quartz rod is 4-5mm, and the lower edge of the aperture is 4-5mm lower than the lower edge of the quartz rod. ,

A liquid nitrogen inlet 13 is provided on the lower left side of the front panel 3 , and a liquid nitrogen outlet 14 is provided on the upper right side of the rear panel 4 for charging and discharging liquid nitrogen.

After everything is ready, extend the liquid nitrogen output pipe into the liquid nitrogen inlet 13. At this time, liquid nitrogen can be sprayed to cool down the ultra-low temperature environment box. After reaching the required temperature, the liquid nitrogen spray rate is reduced, and then the test is started. During the test, the temperature inside the environmental chamber was maintained by controlling the ejection rate of liquid nitrogen to keep the interior at a constant temperature.

The present invention is not only suitable for loading tests, but also suitable for tests that do not need to be loaded. It only needs to fix the test piece at the corresponding position, and does not need the steel backing plate A19, steel bar A20 and steel bar B22. The polyurethane foam plug A24 and the polyurethane foam plug B25 are placed in the hole E11 and the hole F12, as shown in FIG. 5 .

Claims (5)

1. concrete strain measurement test unit under a ultralow temperature, comprise ultra-low temperature surroundings case and measurement mechanism, it is characterized in that, described ultra-low temperature surroundings case is made up of top board (1), base plate (2), header board (3), rear plate (4), left plate (5) and right plate (6), right plate (6) is movable, an openable side plate, so that the placement of test specimen and taking-up;

Circular hole A (7), hole B (8), hole C (9) and hole D (10) is respectively arranged with in the central symmetry position of left plate (5) and right plate (6); Hole A (7) is corresponding with hole D (10) left and right with hole C (9), hole B (8), be respectively arranged with quartz pushrod A (15) and quartz pushrod B (16), quartz pushrod A (15) and quartz pushrod B (16) in the middle of it to build all in advance in concrete sample; Be provided with clock gauge A (17) between two quartz pushrods up and down in left plate (5) side, be provided with clock gauge B (18) between two quartz pushrods up and down in right plate (6) side; Measurement mechanism is drawn in two quartz pushrods and the strain of two clock gauges composition;

Circular hole E (11) and hole F (12) is respectively arranged with in the center of top board (1) and base plate (2), steel backing plate A (19) and rod iron A (20) is provided with between hole E (11) and the upper surface of test specimen (23), rod iron A (20) is through hole E (11), steel backing plate B (21) and rod iron B (22), rod iron B (22) is provided with through hole F (12) between hole F (12) and the lower surface of test specimen (23); By rod iron A (20) and rod iron B (22), external force is loaded to test specimen (23);

The lower left side of header board (3) is provided with liquid nitrogen import (13), the upper right of rear plate (4) is provided with liquid nitrogen outlet (14), is filled with for liquid nitrogen and discharges.

2. concrete strain measurement test unit under ultralow temperature according to claim 1, it is characterized in that, described top board (1), base plate (2), header board (3), rear plate (4), left plate (5) and right plate (6) are polyurethane foam board and make.

3. concrete strain measurement test unit under ultralow temperature according to claim 1, it is characterized in that, described top board (1), base plate (2), header board (3), rear plate (4) and left plate (5) adopt low temperature resistant adhesive glue to bond.

4. concrete strain measurement test unit under ultralow temperature according to claim 1, it is characterized in that, described quartz pushrod A (15) and quartz pushrod B (16) and hole A (7), hole B (8), space between hole C (9) and hole D (10) adopt low temperature rubber cover to fill; The width in above-mentioned each aperture slightly larger than quartz pushrod diameter, and the coboundary in aperture higher than the lower limb in quartz pushrod coboundary 4 ~ 5mm, aperture lower than quartz pushrod lower limb 4 ~ 5mm.

5. concrete strain measurement test unit under ultralow temperature according to claim 1, is characterized in that, described ultra-low temperature surroundings case height is 600 ~ 700, and width is 400 ~ 500, and the degree of depth is 400 ~ 500.