An on-line test apparatus and method for concrete shrinkage

Abstract

This invention discloses an online concrete shrinkage testing device and method, belonging to the field of concrete shrinkage testing technology. It includes a testing mechanism mounted on a base, comprising a slidably mounted testing mechanism and a fixing mechanism. A mold is also slidably mounted on the base, comprising a slidably mounted splicing base plate. A first side plate, a second side plate, a third side plate, and a fourth side plate are rotatably mounted on the splicing base plate, wherein the first and third side plates rotate synchronously, and the second and fourth side plates rotate synchronously. A mating component is slidably mounted on the fourth side plate. The mold in this invention is a splicable abrasive. During use, the abrasive is spliced ​​into a whole, oil is applied inside to form a film, and then grout is poured. After the concrete grout hardens, the first, second, third, and fourth side plates are opened by rotation, achieving demolding of the hardened concrete grout from its sides.

Description

Technical Field

[0001] This invention relates to the field of chassis, and in particular to an online testing device and method for concrete shrinkage. Background Technology

[0002] Concrete shrinkage testing is a key test for assessing the volume stability of concrete due to moisture loss and chemical changes. It is mainly divided into two methods: contact and non-contact. The contact length measurement method includes the use of dial indicators (mechanical or digital), length measuring instruments and measuring nails (pre-embedded or post-attached) for detection. The non-contact monitoring method includes the use of eddy current displacement sensors, reflective targets, and multi-channel acquisition instruments for detection.

[0003] Whether the measurement is conducted by contact or non-contact method, the mixed concrete mortar must be poured into the mold, and the shrinkage test must be performed directly or after hardening. The hardened test block must be demolded during or after the test.

[0004] In the existing technology, the demolding of test blocks is usually done manually. The mold is flipped or disassembled and the hardened test block is taken out for testing, which is quite inconvenient. Summary of the Invention

[0005] This invention provides an online testing device and method for concrete shrinkage, which can solve the problem in the prior art that it is inconvenient to manually flip or disassemble the mold to take out the hardened test block for testing.

[0006] An online concrete shrinkage testing device and method includes a testing mechanism mounted on a base. The testing mechanism includes a slidably mounted testing mechanism and a fixing mechanism. A mold is also slidably mounted on the base. The mold includes a slidably mounted splicing base plate. A first side plate, a second side plate, a third side plate, and a fourth side plate are rotatably mounted on the splicing base plate. The first side plate and the third side plate rotate synchronously, the second side plate and the fourth side plate rotate synchronously, and a mating component is slidably mounted on the fourth side plate.

[0007] Furthermore, the base includes a U-shaped base plate, with a first threaded rod rotatably provided at both ends of the U-shaped base plate. The two ends of the two first threaded rods are respectively provided with a first external thread and a second external thread with opposite thread directions. A first knob is fixedly provided at the connection between the two first threaded rods and the U-shaped base plate. The first knobs on both sides control the rotation of the first threaded rods on both sides. A first sliding rod is also fixedly provided on the U-shaped base plate.

[0008] Furthermore, the testing mechanism includes a first movable plate, which is threadedly engaged with a second external thread on a first threaded rod, and the first movable plate is slidably engaged with a first sliding rod. A measuring gauge is fixedly mounted on the first movable plate.

[0009] Furthermore, the fixing mechanism includes a second movable plate, on which a connecting block is fixedly mounted, and on which a back plate is fixedly mounted. A baffle is connected to the back plate via a first spring, and a plurality of second sliding rods are also fixedly mounted on the baffle. The plurality of second sliding rods pass through the back plate and are connected to the connecting block.

[0010] Furthermore, the mold includes a telescopic cylinder, which is fixedly connected to a U-shaped base plate. The output end of the telescopic cylinder is fixedly connected to a splicing base plate. Several second springs are also connected between the splicing base plate and the U-shaped base plate. Each of the second springs contains a first telescopic rod. The top of the first telescopic rod is fixedly connected to the splicing base plate. A first side plate, a second side plate, a third side plate, and a fourth side plate are rotatably provided around the splicing base plate. The first side plate, the second side plate, the third side plate, and the fourth side plate are interlocked with each other. The first side plate and the third side plate are on opposite sides, and the second side plate and the fourth side plate are on opposite sides. The second side plate has a slot, and the first side plate has a block.

[0011] Furthermore, a third movable plate and a fourth movable plate are fixedly connected to the U-shaped base plate. The third movable plate and the fourth movable plate are slidably connected to the first threaded rod at the unthreaded part and the first sliding rod. The third movable plate and the fourth movable plate are located on both sides of the telescopic cylinder. The first side plate and the third side plate are rotatably disposed between the third movable plate and the fourth movable plate. The second side plate is rotatably connected to the fourth movable plate, and the fourth side plate is rotatably connected to the third movable plate.

[0012] Furthermore, the second side plate and the fourth movable plate are rotatably connected by a first rotating shaft. The end of the first rotating shaft is coaxial and fixedly provided with a first gear. The third side plate is rotatably disposed between the third movable plate and the fourth movable plate via a second rotating shaft, wherein the height of the second rotating shaft is lower than that of the first rotating shaft.

[0013] Furthermore, the first side plate and the third side plate are rotatably connected by a second rotating shaft. A first connecting rod is fixedly mounted on the second rotating shaft on both sides. A second connecting rod is rotatably mounted on each of the two first connecting rods. Both of the two second connecting rods are rotatably connected to the moving blocks. A sliding groove is also provided on the fourth moving plate. Both moving blocks are slidably connected to the sliding groove. A fourth spring is provided between the two moving blocks. A connecting plate is fixedly mounted on each of the sliding grooves. A bracket is also fixedly mounted on both sides of the fourth moving plate. A cylindrical rod is rotatably mounted on each of the two brackets. A third external thread and a fourth external thread are respectively provided on the cylindrical rod. The thread directions of the third external thread and the fourth external thread are opposite, and the third external thread and the fourth external thread are respectively threadedly connected to the two connecting plates. A second knob is also coaxially mounted and fixedly mounted on one end of the cylindrical rod.

[0014] Furthermore, a support plate is fixedly provided on the third and fourth movable plates. A plurality of third springs and a plurality of second telescopic rods are fixedly provided on the support plate. A U-shaped mating plate is fixedly provided at the top of the plurality of third springs and the plurality of second telescopic rods. A pressure rod is fixedly provided at the U-shaped top of the U-shaped mating plate. A first rack is fixedly provided on both sides of the inside of the U-shaped mating plate. The first racks on both sides mesh with the first gear respectively. The fourth side plate is also provided with a groove, and a gasket is installed at the bottom of the groove. A pre-embedded side head can be placed on the gasket. U-shaped sliding rods are also fixedly provided at both ends of the groove on the fourth side plate. The same sliding member is slidably provided on the U-shaped sliding rods on both sides, and a mating part is fixedly provided on the sliding member. A testing method for an online concrete shrinkage testing device includes the following steps: Step 1: First, rotate the first, second, third, and fourth side plates on the mold to a vertical position and put them together. At this time, the spliced ​​bottom plate is at the bottom. Apply oil and lay concrete slurry inside the spliced ​​mold. Place the pre-embedded side head inside the concrete slurry or at both ends. Step Two: After the concrete in the mold has hardened, first draw the grooves outward on the mating parts, and control the first, second, third, and fourth side plates to open outward respectively, so as to demold the sides of the hardened concrete. Then, the splicing base plate is moved upward by the telescopic cylinder. At this time, the hardened concrete test block is located on the splicing base plate and moves synchronously. After rising to a certain height, the testing mechanism and the fixing mechanism move towards both sides of the concrete test block to fix and test its ends. The measuring gauge on the testing mechanism contacts the pre-embedded probe to test the concrete test block.

[0015] Beneficial effects 1. The mold in this invention is a modular abrasive. In use, the abrasive is assembled into a whole, and oil is applied inside to form a film before grouting. After the concrete grout hardens, the first, second, third, and fourth side plates are opened by rotation to demold the sides of the hardened concrete grout. After the film is applied, the spliced ​​base plate rises up and is tested by a testing mechanism. This eliminates the need for manual demolding during the testing process and also eliminates the need for manual alignment of the hardened test block with the testing mechanism. Automatic alignment is achieved by moving the spliced ​​base plate and the testing mechanism, ultimately enabling the testing.

[0016] 2. In this invention, the first side plate and the third side plate are rotated via the first and second connecting rods. When the first and third side plates rotate and open to both sides, as the opening angle increases, the third side plate gradually contacts the pressure rod and gradually squeezes the pressure rod as the opening angle increases. Under the action of several third springs and several second telescopic rods, the U-shaped mating plate moves downward, and at the same time, the first racks on both sides inside move downward synchronously. During the downward movement of the first racks, they mesh with the first gear, thereby realizing the rotation of the first gear. The first gear is fixedly connected to the first rotating shaft, thus realizing the synchronous rotation of the second side plate and the fourth moving plate. The second side plate and the fourth moving plate rotate outward and open to a certain angle. Finally, all the first, second, third, and fourth side plates rotate and open, realizing the demolding of the hardened test block. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention. Figure I ; Figure 2 This is a front view of the overall structure of the present invention; Figure 3 This is a cross-sectional view at point AA of the present invention; Figure 4 This is a schematic diagram of the overall structure of the present invention. Figure II ; Figure 5 This is an enlarged schematic diagram of part A of the present invention; Figure 6 This is a partial structural diagram of the present invention. Figure I ; Figure 7 This is an enlarged schematic diagram of part B of the present invention; Figure 8 This is an enlarged schematic diagram of part C of the present invention; Figure 9 This is an enlarged schematic diagram of part D of the present invention; Figure 10 This is a partial structural diagram of the present invention. Figure II ; Figure 11 This is an enlarged schematic diagram of part E of the present invention.

[0018] Explanation of reference numerals in the attached figures: 100. Base; 200. Testing mechanism; 300. Mold; 400. Fixing mechanism; 101. U-shaped base plate; 102. First threaded rod; 103. First knob; 104. First external thread; 105. Second external thread; 106. First slide rod; 201. First moving plate; 202. Measuring gauge; 203. Controller; 204. First mounting plate; 301. Telescopic cylinder; 302. Second spring; 303. First telescopic rod; 304. Third moving plate; 305. Fourth moving plate; 306. First side plate; 307. Second side plate; 308. Third side plate; 309. Fourth side plate; 310. Gasket; 311. Mating part; 312. Embedded side head; 313. Sliding part; 314. 315. U-shaped slide bar; 316. Splicing base plate; 317. Slot; 318. Locking block; 319. Pressure rod; 320. Third spring; 321. Second telescopic rod; 322. U-shaped mating plate; 323. First gear; 324. First rack; 325. Second rotating shaft; 326. First connecting rod; 327. Moving block; 328. Fourth spring; 329. Slide groove; 330. Connecting plate; 331. Bracket; 332. Cylindrical rod; 333. Fourth external thread; 334. Third external thread; 335. Second knob; 336. Support plate; 401. Second moving plate; 402. Connecting block; 403. Back plate; 404. First spring; 405. Baffle; 406. Second slide bar. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] like Figure 1 As shown in the figure, an online concrete shrinkage testing device provided in this embodiment of the invention includes a base 100, on which a testing mechanism is provided. The shrinkage testing mechanism includes a slidably mounted testing mechanism 200 and a fixing mechanism 400. The testing mechanism 200 and the fixing mechanism 400 are suitable for contact testing scenarios of concrete. The testing mechanism 200 and the fixing mechanism 400 can move independently or synchronously. At the same time, the testing mechanism also includes a non-contact method for testing hardened concrete specimens, including an instrument that uses an eddy current displacement sensor to non-contactly monitor the displacement of a reflective target. Different application scenarios can be selected according to different usage requirements. A mold 300 is also provided on the base 100 between the testing mechanism 200 and the fixing mechanism 400. In this embodiment, the mold 300 is detachable, which facilitates the demolding of the molded and hardened concrete specimens.

[0021] When determining the shrinkage of concrete using a non-contact method, a reflective target needs to be fixed. After the specimen hardens, the reflective target can still be firmly fixed on both sides of the specimen. The displacement change of the target is measured non-contactly using an eddy current displacement sensor. After the test is completed, the mold 300 is used to achieve demolding.

[0022] When the contact method is used to determine the shrinkage of concrete, the test is mainly performed on hardened concrete blocks. First, the blocks need to be demolded using a mold 300. Then, the test mechanism 200 or the fixing mechanism 400 is used to fix the two ends of the blocks in contact, and the shrinkage of the blocks is tested.

[0023] like Figure 2 As shown, the base 100 includes a U-shaped base plate 101. Two first threaded rods 102 are rotatably mounted on both ends of the U-shaped base plate 101. The two ends of the first threaded rods 102 are respectively provided with a first external thread 104 and a second external thread 105 with opposite thread directions. A first knob 103 is fixedly mounted at the connection point between the two first threaded rods 102 and the U-shaped base plate 101. The first knobs 103 on both sides control the rotation of the first threaded rods 102 on both sides. Figure 3 As shown, a first sliding rod 106 is also fixedly installed on the U-shaped base plate 101.

[0024] like Figure 2 As shown, the testing mechanism 200 includes a first movable plate 201, which is threadedly engaged with the second external thread 105 on the first threaded rod 102. The first movable plate 201 is also slidably engaged with the first slide rod 106. A measuring instrument 202 is fixedly mounted on the first movable plate 201, and a detection controller 203 is fixedly mounted at the end of the measuring instrument 202. The controller 203 is electrically connected to the measuring instrument 202. The detection controller 203 is fixed to the first movable plate 201 via a first mounting plate 204. In this embodiment, the controller 203 and the measuring instrument 202 can be digital micrometers, and the readings can be directly displayed.

[0025] like Figure 2As shown, the fixing mechanism 400 includes a second movable plate 401, a connecting block 402 fixedly mounted on the second movable plate 401, a back plate 403 fixedly mounted on the connecting block 402, a baffle 405 connected to the back plate 403 via a first spring 404, and a plurality of second sliding rods 406 fixedly mounted on the baffle 405. In this embodiment, the number of second sliding rods 406 is any number greater than one. The plurality of second sliding rods 406 pass through the back plate 403 and connect to the connecting block 402. In use, the distance between the back plate 403 and the baffle 405 is adjustable. After adjustment, the position of the baffle 405 can be fixed by fixing the second sliding rods 406 to the connecting block 402. The second sliding rods 406 and the connecting block 402 can be fixed by bolts. The baffle 405 is further adjustable. When the movable connecting block 402 cannot achieve complete contact between the baffle 405 and the test block, further adjustment can be achieved through the second sliding rods 406.

[0026] In use, the first threaded rod 102 is rotated by turning the first knob 103. The rotation of the first threaded rod 102 separates the fixing mechanism 400 and the testing mechanism 200. The fixing mechanism 400 first contacts the test block and compresses the first spring 404 to a certain extent. Then the testing mechanism 200 contacts the surface of the test block and gradually gets closer to it, and begins to measure the test block.

[0027] like Figure 2 As shown, the mold 300 includes a telescopic cylinder 301, which is fixedly connected to the U-shaped base plate 101, as follows: Figure 6 As shown, the output end of the telescopic cylinder 301 is fixedly connected to a splicing base plate 315, such as... Figure 2 As shown, several second springs 302 are connected between the splicing base plate 315 and the U-shaped base plate 101. Each of the second springs 302 has a first telescopic rod 303 inside. The top of the first telescopic rod 303 is fixedly connected to the splicing base plate 315. Figure 4 As shown, the splicing base plate 315 is also provided with a first side plate 306, a second side plate 307, a third side plate 308, and a fourth side plate 309 on its four sides, respectively. The first side plate 306 and the third side plate 308 are on opposite sides, as are the second side plate 307 and the fourth side plate 309. When the first side plate 306, the second side plate 307, the third side plate 308, and the fourth side plate 309 are rotated to a vertical position, they are spliced ​​together. Taking the first side plate 306 and the second side plate 307 as an example... Figure 7 As shown, the second side plate 307 is provided with a slot 316, and the first side plate 306 is provided with a locking block 317. When in use, when the first side plate 306 and the second side plate 307 are in a vertical state, the two can be locked together, and there is no gap between the first side plate 306 and the second side plate 307 after locking.

[0028] like Figure 4As shown, a third moving plate 304 and a fourth moving plate 305 are slidably provided on the first threaded rod 102 where there is no external thread and on the first sliding rod 106. The third moving plate 304 and the fourth moving plate 305 are fixedly connected to the U-shaped base plate 101. The third moving plate 304 and the fourth moving plate 305 are located on both sides of the telescopic cylinder 301. The first side plate 306 and the third side plate 308 are rotatably disposed between the third moving plate 304 and the fourth moving plate 305. The second side plate 307 is rotatably connected to the fourth moving plate 305, and the fourth side plate 309 is rotatably connected to the third moving plate 304.

[0029] like Figure 10 and Figure 11 As shown, taking the second side plate 307 and the third side plate 308 as examples, the second side plate 307 and the fourth moving plate 305 are rotatably connected by a first rotating shaft (not marked in the figure). The end of the first rotating shaft is coaxial and fixedly equipped with a first gear 322. The third side plate 308 is rotatably disposed between the third moving plate 304 and the fourth moving plate 305 via a second rotating shaft 324. The height of the second rotating shaft 324 is lower than that of the first rotating shaft. That is, when the first side plate 306 and the third side plate 308 rotate to both sides, the first side plate 306 and the third side plate 308 are in an open state. At this time, the slot 316 separates from the block 317, and the second side plate 307 and the first side plate 306 are opened by the first gear 322. Finally, the first side plate 306, the second side plate 307, the third side plate 308 and the fourth side plate 309 are all in an open state.

[0030] like Figure 4 and Figure 5As shown, the first side plate 306 and the third side plate 308 are rotatably connected by the second rotating shaft 324. First connecting rods 325 are fixedly mounted on the second rotating shafts 324 on both sides. Second connecting rods 326 are rotatably mounted on each of the two first connecting rods 325. Both second connecting rods 326 are rotatably connected to the moving blocks 327. A sliding groove 329 is also provided on the fourth moving plate 305. Both moving blocks 327 are slidably connected to the sliding groove 329. A fourth spring 328 is provided between the two moving blocks 327. Connecting plates 330 are fixedly mounted on the sliding grooves 329. Supports 331 are also fixedly mounted on both sides of the fourth moving plate 305. Cylindrical rods 332 are rotatably mounted on the two supports 331. The cylindrical rods 332 are divided into... The cylindrical rod 332 is provided with a third external thread 334 and a fourth external thread 333. The threads of the third external thread 334 and the fourth external thread 333 are opposite in direction and are threadedly connected to the two connecting plates 330 respectively. One end of the cylindrical rod 332 is also coaxially and fixedly provided with a second knob 335. In use, the cylindrical rod 332 can be rotated by manually turning the second knob 335. The two moving blocks 327 can be moved in opposite directions by the third external thread 334 and the fourth external thread 333. Then, the first connecting rod 325 and the second connecting rod 326 drive the rotation of the second rotating shafts 324 on both sides, which further realizes the rotation and opening of the first side plate 306 and the third side plate 308.

[0031] like Figure 6 and Figure 8As shown, a support plate 336 is also fixedly provided on the third moving plate 304 and the fourth moving plate 305. Several third springs 319 and several second telescopic rods 320 are fixedly provided on the support plate 336. A U-shaped mating plate 321 is also fixedly provided at the top of the third springs 319 and the second telescopic rods 320. A pressure rod 318 is fixedly provided at the U-shaped top of the U-shaped mating plate 321. First racks 323 are also fixedly provided on both sides of the interior of the U-shaped mating plate 321. The first racks 323 on both sides mesh with first gears 322 respectively. During use, when the first side plate 306 and the third side plate 308 rotate to open to both sides, as the opening angle increases, the third side plate 308 gradually contacts the pressure rod 318, and as the opening angle increases, it gradually compresses the pressure rod 318. The pressure rod 318 is then compressed by the third springs 319 and the second... Under the action of the telescopic rod 320, the U-shaped mating plate 321 will move downward, and at the same time, the first racks 323 on both sides inside it will move downward synchronously. During the downward movement of the first racks 323, they will mesh with the first gear 322, thereby realizing the rotation of the first gear 322. The first gear 322 is fixedly connected to the first rotating shaft, thus realizing the rotation of the second side plate 307 and the fourth moving plate 305. The second side plate 307 and the fourth moving plate 305 will rotate outward and open at a certain angle, so that the first side plate 306, the second side plate 307, the third side plate 308 and the fourth side plate 309 can be fully opened. Since there is concrete in the mold 300, after the concrete hardens, the opening of the first side plate 306, the second side plate 307, the third side plate 308 and the fourth side plate 309 can further realize the demolding of the hardened concrete.

[0032] like Figure 6 and Figure 9 As shown, the fourth side plate 309 is also provided with a groove, and a gasket 310 is installed at the bottom of the groove. A pre-embedded side head 312 can be placed on the gasket 310. U-shaped sliding rods 314 are also fixedly provided on both ends of the groove on the fourth side plate 309. The same sliding member 313 is slidably provided on the U-shaped sliding rods 314 on both sides. A mating member 311 is fixedly provided on the sliding member 313. When the mating member 311 slides outward, it can be separated from the groove, and the pre-embedded side head 312 can be taken out from above the groove for easy inspection.

[0033] This embodiment provides a detection method, specifically a test method for an online concrete shrinkage testing device, including the following steps: Step 1: First, rotate the first side plate 306, the second side plate 307, the third side plate 308 and the fourth side plate 309 on the mold 300 to a vertical position and put them in a splicing state. At this time, the splicing bottom plate 315 is at the bottom. Apply oil and lay concrete slurry inside the spliced ​​mold 300. Place the pre-embedded side head 312 inside the concrete slurry or at both ends. Step 2: After the concrete in the mold 300 hardens, first draw the groove outward on the mating part 311, and control the first side plate 306, the second side plate 307, the third side plate 308 and the fourth side plate 309 to open outward respectively, so as to demold the side of the hardened concrete. Then, the splicing base plate 315 is moved upward by the telescopic cylinder 301. At this time, the hardened concrete test block is located on the splicing base plate 315 and moves synchronously. After rising to a certain height, the testing mechanism 200 and the fixing mechanism 400 move towards both sides of the concrete test block to fix and test its two ends. The measuring gauge 202 on the testing mechanism 200 contacts the pre-embedded side head 312 to test the concrete test block.

[0034] In the description of this invention, it should be understood that the terms "upper," "lower," "left," and "right," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or a specific orientational structure and operation. Therefore, they should not be construed as limitations on the invention. Furthermore, "first" and "second" are only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "multiple" means two or more.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. An online concrete shrinkage testing device, characterized in that, The base (100) is equipped with a testing mechanism, which includes a slidingly mounted testing mechanism (200) and a fixing mechanism (400). The base (100) is also equipped with a mold (300), which includes a slidingly mounted splicing base plate (315). The splicing base plate (315) is rotatably equipped with a first side plate (306), a second side plate (307), a third side plate (308), and a fourth side plate (309). The first side plate (306) and the third side plate (308) rotate synchronously, the second side plate (307) and the fourth side plate (309) rotate synchronously, and the fourth side plate (309) is slidably equipped with a mating part (311).

2. The online concrete shrinkage testing equipment as described in claim 1, characterized in that, The base (100) includes a U-shaped base plate (101), with first threaded rods (102) rotatably provided at both ends of the U-shaped base plate (101). The two ends of the two first threaded rods (102) are respectively provided with a first external thread (104) and a second external thread (105) with opposite thread directions. A first knob (103) is fixedly provided at the connection between the two first threaded rods (102) and the U-shaped base plate (101). The first knobs (103) on both sides control the rotation of the first threaded rods (102) on both sides. A first slide rod (106) is also fixedly provided on the U-shaped base plate (101).

3. The online concrete shrinkage testing equipment as described in claim 2, characterized in that, The testing mechanism (200) includes a first movable plate (201), which is threadedly engaged with the second external thread (105) on the first threaded rod (102), and the first movable plate (201) is slidably engaged with the first slide rod (106). A measuring gauge (202) is fixedly provided on the first movable plate (201).

4. The online concrete shrinkage testing equipment as described in claim 3, characterized in that, The fixing mechanism (400) includes a second movable plate (401), a connecting block (402) is fixedly provided on the second movable plate (401), a back plate (403) is fixedly provided on the connecting block (402), a baffle (405) is connected to the back plate (403) through a first spring (404), and a plurality of second sliding rods (406) are also fixedly provided on the baffle (405), and the plurality of second sliding rods (406) pass through the back plate (403) and are connected to the connecting block (402).

5. The online concrete shrinkage testing equipment as described in claim 4, characterized in that, The mold (300) includes a telescopic cylinder (301), which is fixedly connected to a U-shaped base plate (101). The output end of the telescopic cylinder (301) is fixedly connected to a splicing base plate (315). Several second springs (302) are also connected between the splicing base plate (315) and the U-shaped base plate (101). Each of the second springs (302) is provided with a first telescopic rod (303). The top of the first telescopic rod (303) is fixedly connected to the splicing base plate (315). The splicing base plate (315) is also rotatably provided around its perimeter. The first side plate (306), the second side plate (307), the third side plate (308), and the fourth side plate (309) are interlocked with each other. The first side plate (306) and the third side plate (308) are on opposite sides, and the second side plate (307) and the fourth side plate (309) are on opposite sides. The second side plate (307) is provided with a slot (316), and the first side plate (306) is provided with a block (317).

6. The online concrete shrinkage testing equipment as described in claim 5, characterized in that, The U-shaped base plate (101) is fixedly connected to a third movable plate (304) and a fourth movable plate (305). The third movable plate (304) and the fourth movable plate (305) are slidably connected to the first threaded rod (102) where there is no external thread and the first sliding rod (106). The third movable plate (304) and the fourth movable plate (305) are located on both sides of the telescopic cylinder (301). The first side plate (306) and the third side plate (308) are rotatably disposed between the third movable plate (304) and the fourth movable plate (305). The second side plate (307) is rotatably connected to the fourth movable plate (305), and the fourth side plate (309) is rotatably connected to the third movable plate (304).

7. The online concrete shrinkage testing equipment as described in claim 6, characterized in that, The second side plate (307) and the fourth movable plate (305) are rotatably connected by a first rotating shaft. The end of the first rotating shaft is coaxial and fixedly provided with a first gear (322). The third side plate (308) is rotatably disposed between the third movable plate (304) and the fourth movable plate (305) through a second rotating shaft (324), wherein the height of the second rotating shaft (324) is lower than that of the first rotating shaft.

8. The online concrete shrinkage testing equipment as described in claim 7, characterized in that, The first side plate (306) and the third side plate (308) are rotatably connected by a second rotating shaft (324). A first connecting rod (325) is fixedly provided on the second rotating shaft (324) on both sides. A second connecting rod (326) is rotatably provided on each of the two first connecting rods (325). Both second connecting rods (326) are rotatably connected to the moving block (327). A sliding groove (329) is also provided on the fourth moving plate (305). Both moving blocks (327) are slidably connected to the sliding groove (329). A fourth spring (328) is provided between the two moving blocks (327). A connecting plate (330) is fixedly provided on each of the upper parts. A bracket (331) is also fixedly provided on both sides of the fourth movable plate (305). A cylindrical rod (332) is rotatably provided on the two brackets (331). A third external thread (334) and a fourth external thread (333) are respectively provided on the cylindrical rod (332). The thread directions of the third external thread (334) and the fourth external thread (333) are opposite, and the third external thread (334) and the fourth external thread (333) are respectively threadedly connected to the two connecting plates (330). A second knob (335) is also fixedly provided on one end of the cylindrical rod (332) on the same axis.

9. The online concrete shrinkage testing equipment as described in claim 8, characterized in that, The third moving plate (304) and the fourth moving plate (305) are also fixedly provided with a support plate (336). The support plate (336) is fixedly provided with a plurality of third springs (319) and a plurality of second telescopic rods (320). The top ends of the plurality of third springs (319) and the plurality of second telescopic rods (320) are also fixedly provided with a U-shaped mating plate (321). The top U-shaped end of the U-shaped mating plate (321) is fixedly provided with a pressure rod (318). The inner sides of the U-shaped mating plate (321) are also fixedly provided with a first rack (323). The first racks (323) on both sides mesh with the first gear (322) respectively. The fourth side plate (309) is also provided with a groove, and a gasket (310) is installed at the bottom of the groove. A pre-embedded side head (312) can be placed on the gasket (310). U-shaped sliding rods (314) are also fixedly provided on both ends of the groove on the fourth side plate (309). The same sliding member (313) is slidably provided on the U-shaped sliding rods (314) on both sides. A mating member (311) is fixedly provided on the sliding member (313).

10. A testing method for an online concrete shrinkage testing device, applied to the online concrete shrinkage testing device as described in claim 9, characterized in that, Includes the following steps: Step 1: First, rotate the first side plate (306), second side plate (307), third side plate (308) and fourth side plate (309) on the mold (300) to a vertical position and put them in a splicing state. At this time, the splicing bottom plate (315) is at the bottom. Then, apply oil to the inside of the spliced ​​mold (300) and lay concrete slurry. Place the pre-embedded side head (312) inside the concrete slurry or at both ends. Step 2: After the concrete in the mold (300) hardens, the mating parts (311) are first slid out of the groove, and the first side plate (306), the second side plate (307), the third side plate (308) and the fourth side plate (309) are controlled to open outward respectively, so as to demold the side of the hardened concrete. Then, the splicing base plate (315) is moved upward by the telescopic cylinder (301). At this time, the hardened concrete test block is located on the splicing base plate (315) and moves synchronously. After rising to a certain height, the testing mechanism (200) and the fixing mechanism (400) move towards both sides of the concrete test block to fix and test its two ends. The measuring gauge (202) on the testing mechanism (200) contacts the pre-embedded probe (312) to test the concrete test block.

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