A method for measuring compressive creep of concrete specimens

Abstract

A method for measuring the compressive creep of a concrete test block comprises: firstly, making a special concrete test block creep measurement device, which includes a placement plate, a support pole, a crossbeam, a pressure device, a measuring device, and a pressure hanging basket. The placement plate is provided with leveling bolts and a leveling bubble, and the pressure device includes a pressure pole and a pressure plate. When using the device, the placement plate is leveled using the leveling bolts, a suitable pressure plate is selected, the support pole is fixed, and then the pressure device, measuring device, and pressure hanging basket are fixed to the designed position of the crossbeam. The concrete test block to be tested is placed under the pressure plate and adjusted to be centered. A weight of the designed weight is placed on the pressure hanging basket, and the data of the measuring device is recorded to calculate the creep of the concrete test block. By amplifying gravity and applying it to the concrete test block to be tested using the principle of a lever, the amount of weights used and the space occupied by the weights can be reduced. The creep of the concrete test block is amplified by the lever, and the creep of the concrete test block can be calculated by recording the measurement data.

Description

Technical field:

[0001] The invention belongs to the technical field of civil engineering, in particular to the technical field of concrete creep in civil engineering, and specifically relates to a method for measuring the compressive creep of a concrete test block. Background technology:

[0002] Concrete compressive creep is an important indicator for measuring concrete performance. Nowadays, there are many types of concrete creep measurement devices with different structures and each has its own advantages.

[0003] However, the existing concrete specimen compressive creep measurement device still has some shortcomings, mainly including: it is more convenient to use hydraulic method to load the concrete specimen during the test, but the hydraulic loading system is expensive and complex to control, and there will be pressure loss problems during long-term loading; using heavy objects such as weights to load is convenient and the pressure is stable, but it has the disadvantages of requiring many heavy objects and occupying a large volume. Summary of the invention:

[0004] In view of the deficiencies in the prior art, the present invention provides a method for measuring the compressive creep of a concrete test block, which can utilize the principle of leverage to amplify the applied force and creep, thereby facilitating load application and creep measurement.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for measuring the compressive creep of a concrete test block. The measuring method comprises the following steps: a special concrete test block creep measuring device is prepared, the creep measuring device comprises a placing plate, a supporting vertical pole, a crossbeam, a pressure device, a measuring device, and a pressure hanging basket. The placing plate is provided with a leveling bolt and a leveling bubble. The pressure device comprises a pressure vertical pole and a pressure plate. When the special creep measuring device is used, the placing plate is leveled by the leveling bolt, a suitable pressure plate is selected, the supporting vertical pole is fixed, and then the pressure device, the measuring device, and the pressure hanging basket are fixed to the designed position of the crossbeam. The concrete test block to be measured is placed under the pressure plate and adjusted to be centered. A weight of the designed weight is placed on the pressure hanging basket. Data of the measuring device is recorded, and the creep of the concrete test block can be obtained by calculation.

[0007] The placement plate is a rectangular steel plate with a flat surface and a certain rigidity.

[0008] Leveling bolts are provided at the four corners of the placement plate; leveling bubbles are provided on two adjacent sides of the placement plate, and the two leveling bubbles are arranged perpendicular to each other.

[0009] A narrow steel plate is welded to the bottom of the placement plate.

[0010] The support pole is a telescopic pole with a certain rigidity, which is composed of two sections of thick-walled steel pipes with different diameters. The steel pipes are provided with reserved bolt holes, and the bolts are fixed by connecting with different bolt holes.

[0011] The crossbeam is a crossbar with a certain rigidity and is made of steel.

[0012] The pressure rod is a solid steel rod; a thread is provided at the lower end of the pressure rod, and a threaded blind hole is provided at the center of the pressure plate, which is connected to the pressure rod through the thread.

[0013] The pressure plates have various shapes, such as round and square, and pressure plates of different shapes are used according to the concrete test blocks with different cross-sectional shapes.

[0014] The measuring pole is made of a narrow steel plate and is provided with a plurality of bolt holes in the vertical direction. The measuring pole is fixed to the crossbeam by bolts, and the horizontal position and vertical height of the measuring pole can be adjusted.

[0015] The bottom of the pressure hanging basket is made of thin steel plates, and the surrounding barriers are made of wire mesh. A ring is provided on the top of the pressure hanging basket. The ring moves horizontally on the beam, and the pressure hanging basket is hung on the beam through the ring.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The method of the present invention is used to measure the compressive creep of a concrete test block, which is easy to operate. A heavy object is placed in a pressure hanging basket, and the pressure is stable during long-term pressure application. The gravity force is amplified by the lever principle and applied to the concrete test block to be measured, which can reduce the amount of weights used and the space occupied by the weights. The creep of the concrete test block is amplified by the lever principle, which is convenient for recording. The creep of the concrete test block can be calculated by recording the data of the measuring device. Description of the drawings:

[0018] Figure 1 Schematic diagram of the structure of the device of the present invention;

[0019] Figure 2 It is a rear view of the device of the present invention;

[0020] Figure 3 This is a schematic diagram of the connection between the pressure pole and the crossbeam of the present invention;

[0021] Figure 4 Schematic diagram of the rotating device of the present invention.

[0022] Reference numerals in the figures:

[0023] 1-Placement plate, 2-Supporting pole, 3-Beam, 4-Pressure device, 5-Measuring device, 6-Pressure hanging basket, 7-Concrete test block.

[0024] 11-Leveling bolt, 12-Leveling bubble, 13-Narrow steel plate.

[0025] 21- Rotating device.

[0026] 41-pressure pole, 42-pressure plate.

[0027] 51-Measuring pole, 52-Micrometer indicator. Specific implementation method:

[0028] The present invention is further described below in conjunction with specific embodiments. The specific embodiments are further explanations of the principles of the present invention and do not limit the present invention in any way. Technologies that are the same or similar to the present invention do not exceed the scope of protection of the present invention.

[0029] See also Figures 1-4 The present invention provides a method for measuring the compressive creep of a concrete specimen. The specific measurement method steps are as follows:

[0030] S1, Specialized Concrete Specimen Creep Measurement Device: This specialized creep measurement device comprises a placement plate 1, support posts 2, crossbeams 3, a pressure device 4, a measurement device 5, and a pressure basket 6. The placement plate 1 is a rectangular steel plate with a flat surface and a certain degree of rigidity. Leveling bolts 11 are installed at the four corners of the placement plate 1. Leveling bubbles 12 are located perpendicularly on two adjacent sides of the placement plate 1. The placement plate 1 is adjusted to a horizontal position by adjusting the leveling bolts 11 and observing the leveling bubbles 12. A narrow steel plate 13 is welded to the bottom of the placement plate 1 to increase its rigidity and reduce its longitudinal deformation. Support pole 2 is a retractable pole with a certain degree of rigidity, capable of vertical extension and contraction, and perpendicular to support plate 1. Support pole 2 is composed of two sections of thick-walled steel pipes of different diameters, each provided with pre-set bolt holes for bolts to connect and secure. The lower end of support pole 2 is fixed to the left side of support plate 1, and a rotating mechanism 21 is provided at the top, which can rotate within a vertical plane. Crossbeam 3 is a rigid crossbar made of steel. The left end of crossbeam 3 is fixed to the rotating mechanism 21 of support pole 2, allowing crossbeam 3 to rotate within a vertical plane around the rotating mechanism 21. Beam 3 is provided with a scale to determine the relative positions of pressure device 4, measuring device 5, and pressure basket 6. The pressure device 4 consists of a pressure rod 41 and a pressure plate 42. The pressure rod 41 is a solid steel rod, with its lower end detachably fixedly connected to the pressure plate 42 and its upper end fixedly connected to the crossbeam 3. The lower end of the pressure rod 41 is threaded, and the center of the pressure plate 42 is provided with a threaded blind hole, which is connected to the pressure rod 41 via the threaded action. The pressure plate 42 has various shapes, such as round and square, and can be used according to the different cross-sectional shapes of the concrete test blocks 7. The measuring device 5 consists of a measuring rod 51 and a micrometer 52. The upper portion of the measuring rod 51 is detachably and rotatably connected to the crossbeam 3. The measuring rod 51 is made of a narrow steel plate with multiple bolt holes vertically provided. The measuring rod 51 is fixed to the crossbeam 3 by bolts, and the horizontal position and vertical height of the measuring rod 51 are adjustable. The micrometer 52 is fixed to the lower end of the measuring rod 51. The upper end of the pressure basket 6 is hung on the beam 3. The bottom of the pressure basket 6 is made of thin steel plate, and the surrounding barriers are made of wire mesh. A ring is provided on the top of the pressure basket 6, and the ring can move horizontally on the beam 3. The pressure basket 6 is connected to the beam 3 through the ring. Weights or other heavy objects can be placed inside the pressure basket 6. According to the principle of leverage, the force is amplified and applied to the concrete test block 7 to be tested through the beam 3 and the pressure device 4.

[0031] S2, place the placement plate 1 of the specially made creep measurement device on a flat and hard ground, and adjust the placement plate 1 to a level level by observing the leveling bubble 12 and adjusting the leveling bolt 11.

[0032] S3, select and use a suitable pressure plate 42 according to the cross-sectional shape of the concrete test block 7 to be tested, then extend and retract the support pole 2 to a suitable position according to the height of the concrete test block 7 to be tested, and fix the support pole 2 with bolts.

[0033] S4, adjust the pressure device 4, the measuring device 5 and the pressure basket 6 to the designed position, and the distances from the pressure device 4, the measuring device 5, the pressure basket 6 to the center of the rotating device 21 are a, b, and c respectively.

[0034] S5, test and record the force F0 transmitted by the pressure plate 42 when the pressure basket 6 is unloaded.

[0035] S6. Calculate the weight of the weight required for formal loading based on the creep test design load value F required for the test

[0036] S7 , align the concrete test block 7 to be tested and place it on the lower side of the pressure plate 42 in the center, and adjust the height of the measuring device 5 .

[0037] S8, fix the measuring pole 51 and the dial indicator 52, fix the dial indicator 52 to the lower part of the measuring pole 51, and adjust the dial indicator 52 to a suitable height.

[0038] S9, placing a weight or other heavy object with a calculated weight of G in the pressure hanging basket 6.

[0039] S10, record the deformation data m measured by the dial gauge, and calculate the compressive creep of concrete specimen 7 at different ages l is the length of the pressure rod 41, EA is the tensile stiffness of the pressure rod 41, and EI is the bending stiffness of the beam 3.

Claims

1. A method for measuring compressive creep of concrete test blocks, characterized by: The specific steps are as follows: S1, a special concrete test block creep measurement device, the special creep measurement device comprises a placement plate (1), a support pole (2), a crossbeam (3), a pressure device (4), a measuring device (5), and a pressure hanging basket (6); the placement plate (1) is provided with a leveling bolt (11) and a leveling bubble (12); the support pole (2) is perpendicular to the placement plate (1), the lower end is fixed to one side of the placement plate (1), and the top is provided with a rotating device (21), and the rotating device (21) can rotate in a vertical plane; one end of the crossbeam (3) is fixed to the rotating device (21) of the support pole (2) 1), the crossbeam (3) rotates around the rotating device (21) in a vertical plane, and a scale is provided on the crossbeam (3); the pressure device (4) is composed of a pressure vertical rod (41) and a pressure plate (42), the lower end of the pressure vertical rod (41) is fixedly connected to the pressure plate (42), and the upper end is fixedly connected to the crossbeam (3); the measuring device (5) is composed of a measuring vertical rod (51) and a dial indicator (52), the upper part of the measuring vertical rod (51) is rotatably connected to the crossbeam (3), and the dial indicator (52) is fixed to the lower end of the measuring vertical rod (51); the upper end of the pressure hanging basket (6) is hung on the crossbeam (3); S2, placing the placement plate (1) of the special concrete specimen creep measurement device on a flat and hard ground, and adjusting the placement plate (1) to a horizontal position by observing the leveling bubble (12) and adjusting the leveling bolt (11); S3, selecting and using a suitable pressure plate (42) according to the cross-sectional shape of the concrete test block (7) to be tested, then extending and retracting the support rod (2) to a suitable position according to the height of the concrete test block (7) to be tested, and fixing the support rod (2) with bolts; S4, adjusting the pressure device (4), the measuring device (5) and the pressure hanging basket (6) to the designed positions, the distances from the pressure device (4), the measuring device (5), the pressure hanging basket (6) to the center of the rotating device (21) are a, b, and c respectively; S5, test and record the force F0 transmitted by the pressure plate (42) when the pressure basket (6) is empty; S6. Calculate the weight of the weight required for formal loading based on the creep test design load value F required for the test S7, align the concrete test block (7) to be tested and place it on the lower side of the pressure plate (42) in the center, and adjust the height of the measuring device (5); S8, fix the measuring pole (51) and the dial indicator (52), fix the dial indicator (52) to the lower part of the measuring pole (51), and adjust the dial indicator (52) to a suitable height; S9, placing a weight or other heavy object with a calculated weight of G in the pressure basket (6); S10, record the deformation data m measured by the micrometer, and calculate the compressive creep of the concrete specimen (7) at different ages based on the length l of the pressure rod (41), the tensile stiffness EA and the bending stiffness EI of the beam (3).

2. A method for measuring compressive creep of a concrete specimen according to claim 1, characterized in that: The placement plate (1) is a rectangular steel plate with a flat surface and a certain rigidity.

3. The method for measuring compressive creep of a concrete specimen according to claim 1, wherein: Leveling bolts (11) are provided at the four corners of the placement plate (1); and leveling bubbles (12) are provided on two adjacent sides of the placement plate (1), and the two leveling bubbles (12) are arranged perpendicular to each other.

4. The method for measuring compressive creep of a concrete specimen according to claim 1, wherein: A narrow steel plate (13) is welded to the bottom of the placement plate (1).

5. The method for measuring compressive creep of a concrete specimen according to claim 1, wherein: The supporting pole (2) is a telescopic pole with a certain rigidity, which is composed of two sections of thick-walled steel pipes with different diameters. The steel pipes are provided with reserved bolt holes, and the bolts are fixed by connecting with different bolt holes.

6. The method for measuring compressive creep of a concrete specimen according to claim 1, wherein: The crossbeam (3) is a crossbar with a certain rigidity and is made of steel.

7. The method for measuring compressive creep of a concrete specimen according to claim 1, wherein: The pressure rod (41) is a solid steel rod; the lower end of the pressure rod (41) is provided with a thread, and the center of the pressure plate (42) is provided with a threaded blind hole, which is connected to the pressure rod (41) through the thread.

8. The method for measuring compressive creep of a concrete specimen according to claim 1, wherein: The pressure plate (42) has various shapes, such as circular and square, and pressure plates (42) of different shapes are used according to concrete test blocks (7) of different cross-sectional shapes.

9. The method for measuring compressive creep of a concrete specimen according to claim 1, wherein: The measuring pole (51) is made of a narrow steel plate and is provided with a plurality of bolt holes in the vertical direction. The measuring pole (51) is fixed to the crossbeam (3) by bolts. The horizontal position and vertical height of the measuring pole (51) can be adjusted.

10. The method for measuring compressive creep of a concrete specimen according to claim 1, wherein: The bottom of the pressure hanging basket (6) is made of thin steel plates, and the surrounding barriers are made of wire mesh. A ring is provided on the top of the pressure hanging basket (6), and the ring moves horizontally on the beam (3). The pressure hanging basket (6) is hung on the beam (3) through the ring.

Images