Deformation quantity measuring device for concrete alkali activity detection
By using a temperature and humidity test chamber and a laser measuring instrument in the alkali reactivity test of concrete, a constant temperature and humidity environment is provided, which solves the problem of deformation value deviation caused by manually removing concrete specimens and ensures the accuracy of alkali reactivity test.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SINOHYDRO BUREAU 5
- Filing Date
- 2025-05-15
- Publication Date
- 2026-04-24
AI Technical Summary
In the process of testing the alkali reactivity of concrete, when concrete specimens are manually removed from a constant temperature and humidity environment to measure deformation values, changes in environmental temperature and humidity cause significant deviations between the measured deformation values and the true deformation values, affecting the accuracy of the alkali reactivity values.
A temperature and humidity test chamber is used to provide a constant temperature and humidity environment. A laser measuring instrument is used to scan the length, width and height of the concrete specimen at set time points. The deformation is calculated by the control system to avoid taking the concrete specimen out of the constant temperature and humidity environment for measurement, thus ensuring the accuracy of the deformation value.
It enables accurate measurement of the deformation of concrete specimens in a constant temperature and humidity environment, avoiding deviations in deformation values caused by environmental changes and ensuring the accuracy of alkali reactivity value calculation.
Smart Images
Figure CN224163483U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of concrete testing technology, specifically to a deformation measuring device for testing the alkali reactivity of concrete. Background Technology
[0002] Concrete is a general term for engineering composite materials in which aggregates are bound together by cementing materials. Alkali-activity reaction refers to the chemical reaction between concrete aggregates and alkaline substances in cement, admixtures, and additives in concrete. Alkali-activity reaction can cause concrete structures to expand, crack, or even be destroyed. Therefore, it is necessary to test the alkali activity of concrete.
[0003] When conducting alkali reactivity testing, the concrete specimen is first measured to obtain its length, width, and height as initial values. The specimen is then stored in a constant temperature and humidity environment. Weekly, the specimen is removed and measured again to obtain its length, width, and height as deformation values. The difference between the deformation value and the initial values is used to obtain the deformation amount of the concrete specimen. The alkali reactivity value (expansion rate) of the concrete specimen is then calculated based on the deformation amount.
[0004] In the existing alkali reactivity testing process, when concrete specimens are manually removed from the constant temperature and humidity environment, the changes in the temperature and humidity of the environment cause the concrete specimens to shrink, resulting in a significant deviation between the measured deformation value and the actual deformation value of the concrete specimens in the constant temperature and humidity environment. Consequently, the calculated alkali reactivity value is inaccurate. Utility Model Content
[0005] The purpose of this invention is to provide a deformation measurement device for concrete alkali reactivity testing, which solves the technical problem that in the existing concrete alkali reactivity testing process, when the concrete specimen is manually removed from the constant temperature and humidity environment to measure the deformation value, the changes in the temperature and humidity of the environment will cause the concrete specimen to shrink, resulting in a significant deviation between the measured deformation value and the actual deformation value of the concrete specimen in the constant temperature and humidity environment.
[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:
[0007] A deformation measuring device for testing the alkali reactivity of concrete includes a temperature and humidity test chamber, which provides a constant temperature and humidity environment for measuring deformation in the alkali reactivity test of concrete. A laser measuring instrument is installed inside the temperature and humidity test chamber, and the laser measuring instrument is electrically connected to the control system of the temperature and humidity test chamber.
[0008] When the concrete specimen is placed in the temperature and humidity test chamber, the control system controls the laser measuring instrument to work. The laser measuring instrument scans the concrete specimen to obtain the initial values of the length, width and height of the concrete specimen. It can also scan the concrete specimen again at the set measurement time point to obtain the deformation values of the length, width and height of the concrete specimen. The deformation of the concrete specimen is obtained by subtracting the obtained deformation value from the initial value.
[0009] Furthermore, the temperature and humidity test chamber includes a chamber body and a door, with a discharge port provided on the side wall of the chamber body, and the door covering the discharge port.
[0010] Furthermore, the door is connected to the box body via a hinge.
[0011] Furthermore, the cabinet door is equipped with a handle for easy pulling.
[0012] Furthermore, the door of the container is provided with an observation window to facilitate observation of the interior of the container.
[0013] Furthermore, a movable frame for placing concrete specimens is provided below the laser measuring instrument. First sliders are provided on both sides of the movable frame, and a connecting block is provided at the bottom of the movable frame. A first threaded sleeve is provided at the end of the connecting block away from the movable frame.
[0014] The box is provided with a first sliding groove on each of the two opposite side walls inside the box. The first sliding groove extends from the discharge port into the box and the length direction of the first sliding groove is perpendicular to the side wall of the box where the discharge port is provided. The movable frame is slidably disposed in the box through the cooperation of the first slider and the first sliding groove.
[0015] The box is equipped with a first motor. The axis of the output end of the first motor is perpendicular to the side wall of the box where the discharge port is located. The output end of the first motor is coaxially provided with a first threaded rod, and a first threaded sleeve is fitted on the first threaded rod.
[0016] The first motor is electrically connected to the control system.
[0017] Furthermore, a sealing plate is provided inside the housing. The sealing plate is located below the first motor, and a second motor is provided on the lower surface of the sealing plate. The axis of the output shaft of the second motor is perpendicular to the sealing plate, and a second threaded rod is coaxially provided at the output end of the second motor.
[0018] The box body has a rectangular cross-section. A second sliding groove is provided at each of the four circumferential edges inside the box body, with the length of the second sliding groove perpendicular to the plane of the sealing plate. A second threaded sleeve is fitted onto the second threaded rod. A connecting rod is provided on the circumferential sidewall of the second threaded sleeve corresponding to the position of the second sliding groove. A second slider, capable of sliding along the length of the second sliding groove, is provided at the end of the connecting rod away from the second threaded sleeve. A caster wheel is provided on the side of the connecting rod away from the sealing plate. An opening is provided on the bottom surface of the box body corresponding to the position of the caster wheel to facilitate its extension and retraction.
[0019] The second motor is electrically connected to the control system.
[0020] Compared with the prior art, this utility model has at least the following advantages and beneficial effects:
[0021] This invention utilizes a temperature and humidity test chamber to provide a constant temperature and humidity environment for measuring deformation in concrete alkali reactivity testing. Before the test begins, the operator first inputs the measurement time point into the control system of the temperature and humidity test chamber. Then, the concrete specimen to be tested is placed in the chamber. The control system of the chamber controls a laser measuring instrument to scan the concrete specimen, obtaining the length, width, and height values as initial values. When the set measurement time point is reached, the control system of the chamber controls the laser measuring instrument to scan the concrete specimen again, obtaining the length, width, and height values as deformation values. The difference between the deformation value and the initial value is used to obtain the accurate deformation of the concrete specimen. Based on the accurate deformation value, the operator calculates the accurate alkali reactivity value of the concrete specimen. This avoids the problem in traditional alkali reactivity testing where the concrete specimen is manually removed from the constant temperature and humidity environment to measure the deformation value. This avoids the shrinkage caused by changes in temperature and humidity, which leads to a significant deviation between the measured deformation value and the true deformation value of the concrete specimen in the constant temperature and humidity environment. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of a deformation measuring device for detecting the alkali reactivity of concrete provided in this embodiment.
[0023] Figure 2 This is a cross-sectional view of a deformation measuring device for detecting the alkali reactivity of concrete provided in this embodiment.
[0024] Figure 3 This embodiment provides a deformation measuring device for detecting the alkali reactivity of concrete. Figure 2 A magnified view of part A in the middle.
[0025] Figure 4 This embodiment provides a deformation measuring device for detecting the alkali reactivity of concrete. Figure 2 A magnified view of part B in the middle.
[0026] Figure 5 This is a top view of a moving frame for a deformation measuring device used in concrete alkali reactivity testing, as provided in this embodiment.
[0027] The meanings of the labels in the diagram are as follows:
[0028] 1. Casters; 2. Temperature and humidity test chamber; 3. Control system; 4. Door; 5. Handle; 6. Hinge; 7. Observation window; 8. Ventilation duct; 9. Centrifugal fan; 11. Humidity sensor; 12. Temperature sensor; 13. Laser measuring instrument; 14. Moving frame; 15. Connecting block; 16. First threaded sleeve; 17. First threaded rod; 18. First motor; 19. Second slider; 20. Second slide groove; 21. Opening; 22. Second motor; 23. Second threaded rod; 24. Second threaded sleeve; 25. Connecting rod; 26. Heater; 27. Semiconductor cooling chip; 28. Humidifier; 29. First slide groove; 30. First slider; 31. Sealing plate. Detailed Implementation
[0029] The technical solution of this embodiment will be clearly and completely described below with reference to the accompanying drawings, so as to provide a better understanding of the concept of this utility model, the technical problem solved, the technical features constituting the technical solution, and the technical effects brought about.
[0030] The terms "connection" and "fixing" appearing in this utility model description can refer to fixed connection, processing and forming, welding, or mechanical connection. The specific meaning of the above terms in this utility model should be understood according to the specific circumstances.
[0031] In the description of this utility model, the terms "center", "upper", "lower", "horizontal", "inner", "outer", etc., are used only to indicate the orientation or positional relationship for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, and therefore should not be construed as a limitation of this utility model.
[0032] In the embodiments of this application, such as Figure 1 and Figure 2 As shown, a deformation measuring device for detecting the alkali reactivity of concrete includes a temperature and humidity test chamber 2; the temperature and humidity test chamber 2 includes a humidity sensor 11, a temperature sensor 12, a heater 26, a semiconductor cooling chip 27, a humidifier 28 and a control system 3, and a ventilation pipe 8 communicating with the internal cavity of the temperature and humidity test chamber 2 is provided at the top of the temperature and humidity test chamber 2, and a centrifugal fan 9 is provided inside the ventilation pipe 8; a laser measuring instrument 13 is provided inside the temperature and humidity test chamber 2.
[0033] Humidity sensor 11, temperature sensor 12, laser measuring instrument 13, heater 26, semiconductor cooling chip 27, humidifier 28 and centrifugal fan 9 are all electrically connected to control system 3. Control system 3 controls humidity sensor 11, temperature sensor 12, heater 26, semiconductor cooling chip 27, humidifier 28 and centrifugal fan 9 to work together to maintain a constant temperature and humidity environment in temperature and humidity test chamber 2; and uses laser measuring instrument 13 to detect the deformation of concrete specimens placed in temperature and humidity test chamber 2.
[0034] During use, after the staff puts the concrete specimen into the temperature and humidity test chamber 2, they input the constant temperature and humidity values required for the alkali activity test, as well as the measurement time points, into the control system 3 in advance. The control system 3 uses the input temperature and humidity values as the target temperature and target humidity values. After the control system 3 controls the laser measuring instrument 13 to scan the concrete specimen, it obtains the length, width, and height values of the concrete specimen as initial values. The control system 3 saves the initial values and displays them on the screen.
[0035] After the humidity sensor 11 feeds back the actual humidity value collected in the temperature and humidity test chamber 2 to the control system 3, the control system 3 compares the actual humidity value with the target humidity value. When the actual humidity value is less than the target humidity value, the control system 3 controls the humidifier 28 to turn on, and the humidifier 28 humidifies the air inside the temperature and humidity test chamber 2 until the actual humidity value fed back by the humidity sensor 11 is the same as the target humidity value, and then the control system 3 controls the humidifier 28 to turn off. When the actual humidity value is greater than the target humidity value, the control system 3 controls the centrifugal fan 9 to turn on, and extracts the humid air inside the temperature and humidity test chamber 2 until the actual humidity value fed back by the humidity sensor 11 is the same as the target humidity value, and then the control system 3 controls the centrifugal fan 9 to turn off.
[0036] After the temperature sensor 12 feeds back the actual temperature value collected in the temperature and humidity test chamber 2 to the control system 3, the control system 3 compares the actual temperature value with the target temperature value. When the actual temperature value is less than the target temperature value, the control system 3 controls the heater 26 to turn on, and the heater 26 heats the air inside the temperature and humidity test chamber 2 until the actual temperature value fed back by the temperature sensor 12 is the same as the target temperature value, and then the control system 3 controls the heater 26 to turn off. When the actual temperature value is greater than the target temperature value, the control system 3 controls the thermoelectric cooler 27 to turn on, and the thermoelectric cooler 27 cools the air inside the temperature and humidity test chamber 2 until the actual temperature value fed back by the temperature sensor 12 is the same as the target temperature value, and then the control system 3 controls the thermoelectric cooler 27 to turn off.
[0037] When the set measurement time point is reached, the control system 3 controls the laser measuring instrument 13 to scan the concrete specimen in the temperature and humidity test chamber 2 to obtain the length, width, and height values of the concrete specimen at the current time. The length, width, and height values of the concrete specimen at the current time are fed back to the control system 3 as deformation values. The control system 3 uses the deformation value of the concrete specimen to subtract the initial value of the concrete specimen to obtain the deformation value of the concrete specimen. The control system 3 displays the deformation value of the concrete specimen on its screen. The staff can calculate the alkali activity of the concrete specimen by viewing the deformation value of the concrete specimen displayed on the screen of the control system 3.
[0038] By using a constant temperature and humidity environment created by the control system 3 in conjunction with a humidity sensor 11, a temperature sensor 12, a heater 26, a semiconductor cooling chip 27, and a humidifier 28, the control system 3 controls a laser measuring instrument 13 to detect the deformation of the concrete specimen, thus avoiding the need to remove the concrete specimen from the constant temperature and humidity environment. This avoids the problem of deviation between the measured deformation value and the true deformation value of the concrete specimen in the constant temperature and humidity environment caused by the shrinkage of the concrete specimen due to changes in the ambient temperature and humidity.
[0039] The laser measuring instrument 13 can measure the length, width, and height of a concrete specimen. By measuring the length, width, and height of the concrete specimen immediately after it is placed in the temperature and humidity test chamber 2 and at the set measurement time point, and by subtracting the length, width, and height values obtained from the two measurements, the deformation of the concrete specimen can be obtained. The staff can then calculate the alkali reactivity value based on the deformation.
[0040] The laser measuring instrument 13 mentioned above is a three-dimensional laser measuring instrument, the temperature sensor 12 is an LM35 sensor, the humidity sensor 11 is a DHT22 sensor, or other models of detection equipment with the same function, effect and detection accuracy.
[0041] The heater 26 mentioned above is model SQH-12V50W silicone heater, the semiconductor cooling chip 27 is model CL-C067 semiconductor cooling chip, the humidifier 28 is model HumiSysHS-200, or other temperature control devices with the same function, effect and temperature regulation effect.
[0042] In some embodiments, such as Figure 1 As shown, the temperature and humidity test chamber 2 includes a chamber body and a door 4. The side wall of the chamber body is provided with a discharge port, and the door 4 covers the discharge port.
[0043] By placing the box door 4 at the discharge port, it becomes more convenient for staff to pick up and put down concrete specimens.
[0044] In some embodiments, such as Figure 1 As shown, the box door 4 is connected to the box body via a hinge 6.
[0045] In this embodiment, one end of the hinge 6 is fixedly connected to the outer left side wall of the box, and the other end is fixedly connected to the box door 4, which allows the box door 4 to be opened and closed in a space with a relatively narrow width.
[0046] In some embodiments, such as Figure 1 As shown, the aforementioned box door 4 is provided with a handle 5 for easy pulling of the box door 4.
[0047] In this embodiment, by setting the handle 5 on the box door 4, the convenience of opening and closing the box door 4 for the staff can be met.
[0048] In some embodiments, such as Figure 1 As shown, the aforementioned box door 4 is equipped with an observation window 7.
[0049] In this embodiment, an observation window 7 is provided on the door 4 to facilitate staff to observe the state of the concrete specimens inside the temperature and humidity test chamber 2.
[0050] In some embodiments, such as Figure 2 , Figure 4 and Figure 5 As shown, a movable frame 14 for placing concrete specimens is provided below the laser measuring instrument 13. First sliders 30 are symmetrically arranged on both sides of the movable frame 14, and a connecting block 15 is provided at the bottom of the movable frame 14. The connecting block 15 is fixedly connected to the first threaded sleeve 16. Two opposite sidewalls inside the housing are the first sidewall and the second sidewall, both adjacent to the sidewall with the discharge port. First grooves 29 are symmetrically arranged on the first and second sidewalls, extending from the discharge port into the housing. The length direction of the first groove 29 is perpendicular to the sidewall with the discharge port. The movable frame 14 is slidably positioned within the housing through the cooperation of the first sliders 30 and the first grooves 29. A first motor 18 is installed inside the housing. The axis of the output end of the first motor 18 is perpendicular to the sidewall with the discharge port. A first threaded rod 17 is coaxially arranged at the output end of the first motor 18, and the first threaded sleeve 16 is fitted onto the first threaded rod 17. The control system 3 is electrically connected to the first motor 18.
[0051] by Figure 1 Taking the directions shown as reference, the direction in which the door 4 is installed is forward, and the direction in which the hinge 6 is installed is to the left.
[0052] In this embodiment, when a concrete specimen needs to be placed into the temperature and humidity test chamber 2, the chamber door 4 is opened and the control system 3 controls the moving frame 14 to extend from the discharge port. After the concrete specimen is placed in, the test begins. Specifically, the control system 3 controls the first motor 18 to rotate in the forward direction, driving the first threaded rod 17 to rotate. The first threaded rod 17 drives the first threaded sleeve 16 to generate axial displacement, so that the moving frame 14 extends from the discharge port, making it easier to place the concrete specimen. After the concrete specimen is placed, the control system 3 controls the moving frame 14 to move backward. During this process, the control system 3 controls the first motor 18 to rotate in the reverse direction, driving the first threaded rod 17 to rotate. The first threaded rod 17 drives the first threaded sleeve 16 to generate axial displacement until the moving frame 14 contacts the rear side wall inside the temperature and humidity test chamber 2, completing the reset of the moving frame 14.
[0053] When the test is completed and the concrete specimen needs to be removed from the temperature and humidity test chamber 2, open the chamber door 4 and use the control system 3 to control the moving frame 14 to extend from the discharge port, remove the tested concrete specimen from the moving frame 14, and then use the control system 3 to control the moving frame 14 to move backward until the moving frame 14 contacts the rear side wall inside the temperature and humidity test chamber 2 to complete the reset, and then close the chamber door 4.
[0054] During the process of the first threaded rod 17 driving the first threaded sleeve 16 to move, the first slider 30 cooperates with the first slide groove 29 to rotate the movable frame 14, so that the movable frame 14 can only move in a straight line along the direction of the length extension of the first slide groove 29.
[0055] By controlling the first motor 18 through the control system 3, the moving frame 14 can be extended from the discharge port, making it easier for workers to pick up and put down concrete specimens.
[0056] In some embodiments, such as Figure 2 and Figure 3As shown, a sealing plate 31 is provided inside the aforementioned box. The sealing plate 31 is located below the first motor 18, and a second motor 22 is provided on the lower surface of the sealing plate 31. The axis of the output shaft of the second motor 22 is perpendicular to the sealing plate 31, and a second threaded rod 23 is coaxially provided at the output end of the second motor 22. A second sliding groove 20 is provided at the position of each of the four vertical edges on the inner side of the box. The length direction of the second sliding groove 20 is perpendicular to the plane where the sealing plate 31 is located. A second threaded sleeve 24 is sleeved on the second threaded rod 23. A connecting rod 25 is provided on the circumferential side wall of the second threaded sleeve 24 corresponding to the position of the second sliding groove 20. A second slider 19 that can slide along the length direction of the second sliding groove 20 is provided at the end of the connecting rod 25 away from the second threaded sleeve 24. A universal wheel 1 is provided on the side of the connecting rod 25 away from the sealing plate 31. An opening 21 is provided on the bottom surface of the box. The position of the opening 21 corresponds to the position of the universal wheel 1 so that the universal wheel 1 can extend or retract. The second motor 22 is electrically connected to the control system 3.
[0057] In this embodiment, when the temperature and humidity test chamber 2 needs to be moved, the control system 3 controls the connecting rod 25 to move downwards, and pushes out the universal wheel 1 from the opening 21. Specifically, the control system 3 controls the second motor 22 to rotate in the forward direction, drives the second threaded rod 23 to rotate around the axis, and the second threaded rod 23 drives the second threaded sleeve 24 to generate axial displacement, thereby pushing the universal wheel 1 to extend out from the opening 21 of the bottom plate of the temperature and humidity test chamber 2, so as to facilitate the movement of the temperature and humidity test chamber 2.
[0058] After the temperature and humidity test chamber 2 is moved, the control system 3 is used to control the connecting rods 25 to move upward, and the casters 1 are retracted into the temperature and humidity test chamber 2. Specifically, the control system 3 controls the second motor 22 to rotate in the reverse direction, driving the second threaded rod 23 to rotate around its axis. The second threaded rod 23 drives the second threaded sleeve 24 to generate axial displacement, thereby retracting the casters 1 installed on the four connecting rods 25 from the opening 21 of the bottom plate of the temperature and humidity test chamber 2, so that the bottom plate of the temperature and humidity test chamber 2 directly contacts the ground to ensure the stability of the equipment.
[0059] During the process of the second threaded rod 23 driving the second threaded sleeve 24 to move, due to the mutual cooperation between the second slide groove 20, the second slider 19 and the connecting rod 25, the rotation of the second threaded sleeve 24 is constrained, so that the second threaded sleeve 24 can only move in a straight line along the direction of the length extension of the second slide groove 20.
[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it; although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.
Claims
1. A deformation measuring device for testing the alkali reactivity of concrete, comprising a temperature and humidity test chamber (2), wherein the temperature and humidity test chamber (2) provides a constant temperature and humidity environment for measuring deformation in the alkali reactivity testing of concrete, characterized in that: A laser measuring instrument (13) is installed inside the temperature and humidity test chamber (2), and the laser measuring instrument (13) is electrically connected to the control system (3) of the temperature and humidity test chamber (2); When the concrete specimen is placed in the temperature and humidity test chamber (2), the control system (3) controls the laser measuring instrument (13) to work. The laser measuring instrument (13) scans the concrete specimen to obtain the initial values of the length, width and height of the concrete specimen. It can also scan the concrete specimen at the set measurement time point to obtain the deformation values of the length, width and height of the concrete specimen. The deformation of the concrete specimen is obtained by subtracting the obtained deformation value from the initial value.
2. A deformation measuring device for use in the detection of alkali reactivity of concrete according to claim 1, characterized in that: The temperature and humidity test chamber (2) includes a chamber body and a door (4). The side wall of the chamber body is provided with a discharge port, and the door (4) covers the discharge port.
3. A deformation measuring device for use in the detection of alkali reactivity of concrete according to claim 2, characterized in that: The door (4) is connected to the box body by a hinge (6).
4. The deformation measuring device for use in the detection of alkali reactivity of concrete according to claim 3, characterized in that: The box door (4) is provided with a handle (5) for easy pulling.
5. A deformation measuring device for use in the detection of alkali reactivity of concrete according to claim 4, characterized in that: The box door (4) is provided with an observation window (7) to facilitate observation of the inside of the box.
6. A deformation measuring device for use in the detection of alkali reactivity of concrete according to claim 2, characterized in that: Below the laser measuring instrument (13) is a movable frame (14) for placing concrete specimens. A first slider (30) is provided on both sides of the movable frame (14). A connecting block (15) is provided at the bottom of the movable frame (14). A first threaded sleeve (16) is provided at the end of the connecting block (15) away from the movable frame (14). The box is provided with two opposite side walls. The first slide groove (29) extends from the discharge port into the box. The length direction of the first slide groove (29) is perpendicular to the side wall of the box where the discharge port is provided. The movable frame (14) is slidably disposed in the box through the cooperation of the first slider (30) and the first slide groove (29). The box is equipped with a first motor (18), the axis of the output end of the first motor (18) is perpendicular to the side wall of the box where the discharge port is located, the output end of the first motor (18) is coaxially equipped with a first threaded rod (17), and a first threaded sleeve (16) is sleeved on the first threaded rod (17). The first motor (18) is electrically connected to the control system (3).
7. A deformation measuring device for use in the detection of alkali reactivity of concrete according to claim 6, characterized in that: A sealing plate (31) is provided inside the box. The sealing plate (31) is located below the first motor (18), and a second motor (22) is provided on the lower surface of the sealing plate (31). The axis of the output shaft of the second motor (22) is perpendicular to the sealing plate (31), and a second threaded rod (23) is coaxially provided at the output end of the second motor (22). The cross-section of the box is rectangular. The four vertical edges on the inner side of the box are provided with second grooves (20). The length of the second grooves (20) is perpendicular to the plane of the sealing plate (31). A second threaded sleeve (24) is fitted on the second threaded rod (23). A connecting rod (25) is provided on the circumferential side wall of the second threaded sleeve (24) corresponding to the position (20) of the second groove. A second slider (19) is provided at the end of the connecting rod (25) away from the second threaded sleeve (24) and can slide along the length of the second groove (20). A universal wheel (1) is provided on the side of the connecting rod (25) away from the sealing plate (31). An opening is provided on the bottom of the box corresponding to the position of the universal wheel (1) to facilitate the extension and retraction of the universal wheel (1). The second motor (22) is electrically connected to the control system (3).