A cylindrical solid concrete compressive strength testing device

Abstract

A cylindrical solid concrete compressive strength testing device includes a bow-shaped specimen located in the cylindrical solid concrete, on which a metal pressure head, a micro screw hydraulic jack, a spherical support, and a reaction beam are arranged in sequence; the two ends of the reaction beam are respectively connected to the two ends of a metal tank chain and the cylindrical solid concrete, the metal pressure head, the micro screw hydraulic jack, and the spherical support are clamped therein. The present invention clamps the cylindrical solid concrete by the reaction beam and the metal tank chain, and then applies pressure to the bow-shaped specimen by the metal pressure head, the micro screw hydraulic jack, and the spherical support until the bow-shaped specimen is damaged in a spade shape, reads the maximum spade-shaped damage load value, and infers the concrete compressive strength according to the conversion formula established between the concrete compressive strength and the spade-shaped damage load value. The present invention has reasonable design, accurate detection, and strong practicality.

Description

Technical Field

[0001] The invention relates to a device for detecting the compressive strength of cylindrical solid concrete. Background Art

[0002] Compressive strength is one of the important performance parameters of concrete, which is directly related to the quality, safety and normal use of concrete structural components and even the entire project. Therefore, testing the compressive strength of solid concrete is a very important task.

[0003] In the prior art, there are many commonly used methods for testing the compressive strength of solid concrete, which are briefly introduced as follows: (1) Shear compression method. Using a concrete shear compression instrument, a pressure perpendicular to the pressure-bearing surface is applied to the right-angled surface of the concrete component, causing local shear compression failure on the right-angled side of the concrete component, and the compressive strength of the concrete component is estimated based on the shear pressure at this time. The shortcomings of this method are: it is impossible to test concrete without right-angled sides, such as cylindrical bridge pier concrete, which affects the practicality of the test. (2) Core drilling method. Drill concrete specimens on concrete components and process them into standard core samples, and then perform compressive strength tests on pressure testing machines. The shortcomings of this test method are: since the size of the standard core sample is ø100×100㎜, on the one hand, it causes great damage to the structure, and on the other hand, it is impossible to take samples when the steel bars are dense, which affects the practicality of the test. (3) Rebound method. Based on the relationship between the surface hardness and strength of the concrete component, the compressive strength of the concrete component is estimated. The shortcomings of this test method: the compressive strength derived from the relationship between surface hardness and strength is of low accuracy, which affects the accuracy of the test; it is not applicable to concrete with an age of more than 1000 days and a curved radius of less than 250mm, which affects the practicality of the test. (4) Ultrasonic rebound comprehensive method. The compressive strength of concrete is estimated based on the hardness of the concrete component surface and the ultrasonic wave velocity in the concrete component. The shortcomings of this test method: the test operation process is relatively cumbersome, there are many factors affecting the test, and it is easy to produce multiple test deviations, which affects the accuracy of the test; it is not applicable to concrete with an age of more than 2000 days and curved surfaces, such as cylindrical bridge pier concrete, which affects the practicality of the test. (5) Pull-out method. The compressive strength of concrete is estimated based on the pull-out force when the concrete component is destroyed within 30mm of the surface of the concrete component. The shortcomings of this test method: the test process requires complex drilling and grooving processes; it is impossible to test curved surface concrete, such as cylindrical bridge pier concrete, which affects the practicality of the test. (6) Pull-off method. On the hardened concrete component, a core specimen with a diameter of 44 mm and a depth of 44 mm is drilled, and a pull-off test is performed using a device with an automatic clamping test specimen. The concrete compressive strength is estimated based on the pull-off strength value of the core specimen. The shortcomings of this detection method are: when calculating the stress of the pull-off specimen, it is necessary to measure the diameter size at a mutually perpendicular position close to the fracture of the specimen. Due to the small diameter of the specimen, accurate measurement is difficult, which affects the detection accuracy.

[0004] In summary, when testing the compressive strength of cylindrical concrete, the above methods all have various shortcomings, so innovative designs are needed. Summary of the invention

[0005] The present invention proposes a device for detecting the compressive strength of cylindrical solid concrete with reasonable design, strong practicability and accurate detection, and a method using the device. The device and the method can solve the problems existing in various existing methods for detecting the compressive strength of cylindrical solid concrete.

[0006] The technical solution adopted by the present invention is: a cylindrical solid concrete compressive strength testing device, including an arched specimen located in the cylindrical solid concrete, on which a metal pressure head, a micro screw hydraulic jack, a spherical support, and a reaction beam are arranged in sequence; the two ends of the reaction beam are respectively connected to the two ends of the metal tank chain and the cylindrical solid concrete, the metal pressure head, the micro screw hydraulic jack, and the spherical support are clamped therein. The present invention clamps the cylindrical solid concrete by the reaction beam and the metal tank chain, and then applies pressure to the arched specimen by the metal pressure head, the micro screw hydraulic jack, and the spherical support until the arched specimen is damaged in a spade shape, reads the maximum spade-shaped damage load value, and infers the concrete compressive strength according to the conversion formula established between the concrete compressive strength and the spade-shaped damage load value.

[0007] Furthermore, the bow-shaped specimen includes a bow-shaped surface and a compression surface; the bow-shaped surface is a minor arc, located on the longitudinal section of the cylindrical solid concrete, and has a sagittal height of not less than 60 mm; the compression surface is a rectangle, located on the surface of the cylindrical solid concrete, intersecting the bow-shaped surface perpendicularly, with the long side coinciding with the chord of the bow-shaped surface, and the short side not less than 20 mm.

[0008] Furthermore, the metal pressure head is cut along the longitudinal axis from a cylinder with a diameter of 40 mm. The longitudinal axis of the longitudinal section intersects the chord of the bow surface of the bow specimen perpendicularly at the midpoint of the chord, and the longitudinal section is in the same plane as the bow surface of the bow specimen; one end of the metal pressure head is in contact with the pressure surface of the bow specimen, and the other end is fixedly connected to the bottom surface of the micro-screw hydraulic jack; the line connecting the center of gravity of the two ends of the metal pressure head coincides with the extension line of the longitudinal axis of the micro-screw hydraulic jack.

[0009] Furthermore, the top surface of the micro screw hydraulic jack is connected to the bottom surface of the reaction beam through a spherical support; and the micro screw hydraulic jack is provided with a digital pressure gauge.

[0010] Furthermore, the reaction beam is made of steel and is rectangular in shape, with the upper and lower bottom surfaces parallel to the compression surface of the bow-shaped specimen and a length greater than (the diameter of the cylindrical solid concrete + 2 times the thickness of the metal tank chain connection hole) by at least 40 mm.

[0011] Furthermore, both ends of the metal tank chain are provided with connection holes matching the reaction beam and into which the end of the reaction beam can be inserted.

[0012] The beneficial effects of the present invention are as follows: (1) During the testing process, the cylindrical solid concrete is clamped by the reaction beam and the metal tank chain ring, and then the pressure is applied to the arched sample by the metal pressure head, the micro screw hydraulic jack, and the spherical support until the arched sample is damaged in a spade shape, and the maximum spade-shaped damage load value is read. The concrete compressive strength is reasonably designed and the test is accurate according to the conversion formula established between the concrete compressive strength and the spade-shaped damage load value. (2) The instruments and equipment used are easy to process and purchase, have great promotion value, and are highly practical. (3) The problems existing in various existing methods for testing the compressive strength of cylindrical solid concrete are solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a front view schematic diagram of the present invention.

[0014] Figure 2 It is an AA plan view schematic diagram of the present invention.

[0015] Figure 3 It is a schematic diagram of BB plan view of the present invention.

[0016] Figure 4 It is a CC top view schematic diagram of the present invention.

[0017] Figure 5 It is a schematic top view of DD of the present invention.

[0018] Figure 6 It is a schematic top view of EE of the present invention.

[0019] Figure 7 It is a picture of the metal tank chain of the present invention. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with specific embodiments, but the present invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all possible alternatives, improvements and equivalents within the scope of the claims.

[0021] Reference Figure 1-7A cylindrical solid concrete compressive strength testing device comprises a bow-shaped sample 8 located in a cylindrical solid concrete 11, on which a metal pressure head 7, a micro screw hydraulic jack 6, a spherical support 3, and a reaction beam 2 are arranged in sequence; the two ends of the reaction beam 2 are respectively connected to the two ends of a metal tank chain 10 and the cylindrical solid concrete 11, the metal pressure head 7, the micro screw hydraulic jack 6, and the spherical support 3 are hooped therein. The present invention hoops the cylindrical solid concrete 11 by means of the reaction beam 2 and the metal tank chain 10, and then applies pressure to the bow-shaped sample 8 by means of the metal pressure head 7, the micro screw hydraulic jack 6, and the spherical support 3 until the bow-shaped sample 8 is damaged in a spade shape, reads the maximum spade-shaped damage load value, and estimates the concrete compressive strength according to the conversion formula established between the concrete compressive strength and the spade-shaped damage load value.

[0022] The cylindrical concrete solid 11 described in this embodiment has a diameter of 500 mm.

[0023] The bow-shaped specimen 8 described in this embodiment includes a bow-shaped surface and a pressure surface; the bow-shaped surface is a minor arc, located on the longitudinal section of the cylindrical solid concrete 11, with a sagittal height of 60 mm and a chord length of 170 mm; the pressure surface is a rectangle, located on the surface of the cylindrical solid concrete, intersecting the bow-shaped surface perpendicularly, with the long side coinciding with the chord of the bow-shaped surface, and the short side 23 mm.

[0024] The metal pressure head 7 described in this embodiment is formed by cutting a cylinder with a diameter of 40 mm along the longitudinal axis. The longitudinal axis of the longitudinal section intersects the chord of the bow surface of the bow specimen 8 perpendicularly at the midpoint of the chord, and the longitudinal section is in the same plane as the bow surface of the bow specimen 8; one end of the metal pressure head 7 is in contact with the pressure surface of the bow specimen 8, and the other end is fixedly connected to the bottom surface of the micro screw hydraulic jack 6; the connecting line of the center of gravity of the two ends of the metal pressure head 7 coincides with the extension line of the longitudinal axis of the micro screw hydraulic jack 6.

[0025] The top surface of the micro screw hydraulic jack 6 described in this embodiment is connected to the bottom surface of the reaction beam 2 through a spherical support 3; the micro screw hydraulic jack 6 is provided with a digital pressure gauge 4.

[0026] The reaction beam 2 described in this embodiment is made of steel and is rectangular in shape. The upper and lower bottom surfaces are parallel to the pressure-bearing surface of the bow-shaped test specimen 8, and the length is 600 mm, the width is 50 mm, and the height is 40 mm.

[0027] Both ends of the metal tank chain 10 described in this embodiment are provided with connecting holes 1 that match the reaction beam 2 and can be used to insert the end of the reaction beam 2. The connecting hole 1 has a width of 51 mm, a height of 41 mm, and a thickness of 30 mm.

[0028] The detection steps of this embodiment are as follows: (1) Use a portable concrete polisher to grind the surface of the cylindrical solid concrete 11 to form a rectangular plane of 170 mm × 50 mm and parallel to the longitudinal axis of the cylindrical solid concrete 11; (2) Use a portable concrete cutter, install a 180 mm diameter diamond cutting blade, and cut a vertical cut downward along the line connecting the midpoints of the short sides of the rectangular plane to form a positioning groove 9 and a bow-shaped sample 8; (3) Encircle the cylindrical solid concrete 11 with a metal tank chain 10, and insert the two ends of the reaction beam 2 into the connecting hole 1 respectively; (4) Place a metal pressure head 7, a micro screw hydraulic jack on the pressure surface of the bow-shaped sample 8 in sequence. 6. Spherical support 3, the longitudinal axis of the longitudinal section of the metal pressure head 7 intersects the chord of the bow surface of the bow specimen 8 at right angles at the midpoint of the chord, the longitudinal section is in the same plane as the bow surface of the bow specimen 8, and the top surface of the micro screw hydraulic jack 6 is connected to the bottom surface of the reaction beam 2 through the spherical support 3; (5) Keeping the upper and lower bottom surfaces of the reaction beam 2 parallel to the pressure surface of the bow specimen 8, rotate the force screw 5 on the micro screw hydraulic jack 6 to apply pressure to the bow specimen 8 until the bow specimen 8 is damaged in a spade shape, read the maximum spade-shaped damage load value, and estimate the concrete compressive strength based on the conversion formula established between the concrete compressive strength and the spade-shaped damage load value.

[0029] In this embodiment, the conversion formula is as follows:

[0030] Yi=AXi+B

[0031] Wherein: Yi is the converted value (MPa) of the compressive strength of the i-th cylindrical solid concrete 11 when detected by the detection device; Xi is the maximum spade-shaped failure load value (N) applied to the i-th cylindrical solid concrete 11 when detected by the detection device; A and B are the regression coefficients of the regression equation.

[0032] Of course, in addition to the above formula, the conversion formula between the concrete compressive strength and the spade failure load value may also be other formulas and is not limited to the above formula.

Claims

1. A cylindrical concrete compressive strength testing device, characterized in that: The invention comprises an arched specimen located in a cylindrical solid concrete, on which a metal pressure head, a micro screw hydraulic jack, a spherical support and a reaction beam are arranged in sequence; the arched specimen is formed by grinding the surface of the cylindrical solid concrete to form a rectangular plane parallel to the longitudinal axis of the cylindrical solid concrete, and a longitudinal cut is made along the line connecting the midpoints of the short sides of the rectangular plane; the arched specimen comprises an arched surface and a pressure surface; the arched surface is a minor arc, located on the longitudinal section of the cylindrical solid concrete, and the sagittal height is not less than 60 mm; the pressure surface is a rectangle, located on the surface of the cylindrical solid concrete, perpendicularly intersecting the arched surface, and the chord weight of the long side and the arched surface is The metal pressure head is cut from a cylinder with a diameter of 40 mm along the longitudinal axis, and the longitudinal axis of the longitudinal section intersects the chord of the bow surface of the bow specimen perpendicularly at the midpoint of the chord, and the longitudinal section is in the same plane as the bow surface of the bow specimen; one end of the metal pressure head is in contact with the pressure surface of the bow specimen, and the other end is fixedly connected to the bottom surface of the micro-screw hydraulic jack; the center of gravity line at both ends of the metal pressure head coincides with the extension line of the longitudinal axis of the micro-screw hydraulic jack; the two ends of the reaction beam are respectively connected to the two ends of the metal tank chain and the cylindrical solid concrete, metal pressure head, micro-screw hydraulic jack, and spherical support are hooped therein.

2. A cylindrical solid concrete compressive strength testing device according to claim 1, characterized in that: The top surface of the micro screw hydraulic jack is connected to the bottom surface of the reaction beam through a spherical support; the micro screw hydraulic jack is provided with a digital pressure gauge.

3. A cylindrical solid concrete compressive strength testing device according to claim 1, characterized in that: The reaction beam is made of steel and is rectangular in shape, with upper and lower bottom surfaces parallel to the compression surface of the bow-shaped specimen.

4. A cylindrical solid concrete compressive strength testing device according to claim 1, characterized in that: Both ends of the metal tank chain are provided with connection holes which match the reaction force cross beam and can be sleeved with the end of the reaction force cross beam.

5. A method for testing the compressive strength of cylindrical concrete, using the testing device as claimed in claim 1, comprising the following testing steps: (1) using a portable concrete polisher to grind the surface of the cylindrical concrete to form a rectangular plane of 170 mm × 50 mm and parallel to the longitudinal axis of the cylindrical concrete; (2) using a portable concrete cutter, installing a 180 mm diameter diamond cutting blade, and cutting a vertical cut downward along the line connecting the midpoints of the short sides of the rectangular plane to form a positioning groove and a bow-shaped specimen; (3) encircling the cylindrical concrete with a metal tank chain, and inserting the two ends of the reaction beam into the connection holes respectively; (4) on the compressive surface of the bow-shaped specimen Place a metal pressure head, a micro screw hydraulic jack, and a spherical support in sequence. The longitudinal axis of the longitudinal section of the metal pressure head intersects the chord of the bow surface of the bow specimen perpendicularly at the midpoint of the chord. The longitudinal section is in the same plane as the bow surface of the bow specimen. The top surface of the micro screw hydraulic jack is connected to the bottom surface of the reaction beam through the spherical support. (5) Keep the upper and lower bottom surfaces of the reaction beam parallel to the pressure surface of the bow specimen, rotate the force screw on the micro screw hydraulic jack, and apply pressure to the bow specimen until the bow specimen fails in a spade shape. Read the maximum spade failure load value, and infer the concrete compressive strength based on the conversion formula established between the concrete compressive strength and the spade failure load value.

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