Device and method for testing expansion degree of ultra-high performance concrete

Abstract

The invention discloses an ultra-high performance concrete expansion degree testing device and method, and belongs to the technical field of concrete testing. The device comprises a control box and a mortar stirrer, a circuit breaker, a current and voltage detection sensor, a contactor and a controller are arranged in the control box, the circuit breaker is connected with the contactor, the current and voltage detection sensor is connected to a connecting circuit of the circuit breaker and the contactor in series, and the contactor is connected with a stirrer motor of the mortar stirrer. The circuit breaker is connected with the controller, and the controller is connected with the current and voltage detection sensor, the contactor and the display screen. The method comprises the following steps: preparing a series of ultra-high performance concrete slurries with different expansion degrees, reading a current value, and actually measuring the expansion degrees of the slurries to obtain a function relational expression of the current and the expansion degrees of the slurries; determining an expansion degree range value of the ultra-high performance concrete; calculating to obtain a current range value; preparing ultra-high performance concrete, and reading a current value; it is determined whether the tested current value is within the calculated current value range.

Description

Technical Field

[0001] This invention belongs to the field of concrete testing technology, specifically relating to a device and method for testing the spreadability of ultra-high performance concrete. Background Technology

[0002] Ultra-high performance concrete (UHVPC), hailed as the concrete of the 21st century for its superior performance, is the most innovative cement-based engineering material of the past three decades, representing a significant leap forward in engineering material performance. With the advancement and development of green concrete engineering materials, UHVPC has attracted considerable attention from experts for its role in improving the environment, enhancing economic efficiency, and solving complex engineering problems. However, due to its high slurry viscosity, UHVPC requires stringent construction conditions. During mix proportioning and mixing, real-time spread tests are necessary to determine the slurry's fluidity. According to relevant standards (T / CECS864-2021), the fluidity of UHVPC slurry is currently primarily evaluated through spread tests, a process that often requires 1-2 people, making it time-consuming and labor-intensive. Cement mortar mixers can only mix the tested cement mortar at two speeds (high and low), making it impossible to determine when mixing reaches the required standard or how the torque changes with different cement mortar formulations during mixing. Summary of the Invention

[0003] The purpose of this invention is to provide a device for testing the spreadability of ultra-high performance concrete, so as to solve the problem that existing methods for testing the flowability of ultra-high performance concrete are time-consuming and labor-intensive.

[0004] Another objective of this invention is to provide a method for testing the spreadability of ultra-high performance concrete.

[0005] The technical solution of this invention is: an ultra-high performance concrete scalability testing device, comprising a control box and a mortar mixer. The control box is equipped with a circuit breaker, a current and voltage detection sensor, a contactor, and a controller. The circuit breaker is connected to an external power source via a power cord and is connected to the contactor. The current and voltage detection sensor is connected in series in the connection circuit between the circuit breaker and the contactor. The contactor is connected to the mixer motor of the mortar mixer. The circuit breaker is connected to the controller. A display screen is provided on the surface of the control box. The controller is connected to the current and voltage detection sensor, the contactor, and the display screen respectively.

[0006] As a further improvement of the present invention, a control button is provided on the surface of the control box, and the control button is connected to the contactor.

[0007] As a further improvement of the present invention, a gateway is provided in the control box, the circuit breaker is connected to the gateway, and the gateway is connected to the controller and the display screen respectively.

[0008] As a further improvement of the present invention, the control box is provided with an inspection door.

[0009] A method for testing the flowability of ultra-high performance concrete, using the aforementioned ultra-high performance concrete flowability testing device, includes the following steps: A. Prepare a series of ultra-high performance concrete slurries with different spread, mix them with a mortar mixer, and after the current stabilizes on the display screen, read the current value and measure the slurry spread. Based on the data of the current value and the corresponding slurry spread, plot the data curve to obtain the functional relationship between the current and the slurry spread. B. Determine the range of scalability values ​​for the ultra-high performance concrete based on the required workability of the ultra-high performance concrete. C. Substitute the current into the functional relationship between the current and the slurry spread based on the spread range value. ， The current range value is calculated; D. Prepare ultra-high performance concrete and pour it into the mortar mixer. Turn on the circuit breaker, set the mixing task mode through the controller, and then turn on the contactor. After the current stabilizes on the display screen, read the current value. E. Determine whether the tested current value is within the calculated current value range. If the tested current value is not within the calculated current value range, then re-prepare the ultra-high performance concrete. Conversely, if the tested current value is within the calculated current value range, it means that the workability of the prepared ultra-high performance concrete meets the requirements. Further test its spreadability and carry out the next molding work.

[0010] The beneficial effects of this invention are: 1. The testing method of this invention relies on measuring the motor current during the mixing process to reflect the mixing torque and plotting the generated data curve. A functional relationship between the current and the spreadability of ultra-high performance concrete slurry is obtained. When developing a new formula, only the current value needs to be read to compare with the previously established data curve to determine the slurry spreadability, providing a new dimension of data reference for the new formula and enabling rapid determination of whether the mixing meets the standards. This method can determine the fluidity of the slurry during the mixing process, providing assistance for cement mortar experimental research and improving experimental efficiency.

[0011] 2. The testing device of this invention has a simple structure and can be directly integrated with existing mortar mixers, making it easy to implement. The device is simple to operate, convenient to test, and can be completed by one person, reducing human error and saving time and effort. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of the ultra-high performance concrete spreadability testing device of the present invention; Figure 2 This is a control principle diagram of the ultra-high performance concrete spreadability testing device of the present invention; Figure 3 This is a data curve showing the relationship between current and slurry spread in a specific embodiment of the present invention.

[0013] In the diagram: 1-Control box; 2-Aircraft line; 3-Mortar mixer; 4-Circuit breaker; 7-Controller; 8-Contaminator; 9-Gateway; 12-Transformer; 14-Control button; 15-Inspection door; 16-Display screen; 17-Current and voltage detection sensor; 18-Handle; 19-Power cord; 20-Mixer motor. Detailed Implementation

[0014] The present invention will be further described in detail below with reference to specific embodiments.

[0015] Example 1 like Figure 1 , Figure 2 As shown, an ultra-high performance concrete scalability testing device includes a control box 1 and a mortar mixer 3. The control box 1 is equipped with a circuit breaker 4, a current and voltage detection sensor 17, a contactor 8, and a controller 7. The circuit breaker 4 is connected to an external power source via a power cord 19 and is connected to the contactor 8. The current and voltage detection sensor 17 is connected in series in the connection circuit between the circuit breaker 4 and the contactor 8. The contactor 8 is connected to the mixer motor 20 of the mortar mixer 3 via an aviation wire 2. The circuit breaker 4 is connected to the controller 7 via a transformer 12. A display screen 16 is provided on the surface of the control box 1. The controller 7 is connected to the current and voltage detection sensor 17, the contactor 8, and the display screen 16.

[0016] A control button 14 is provided on the surface of the control box 1, and the control button 14 is connected to the contactor 8.

[0017] The control box 1 is equipped with a gateway 9. The circuit breaker 4 is connected to the gateway 9 through the transformer 12. The gateway 9 is connected to the controller 7 and the display screen 16 respectively.

[0018] The control box 1 is equipped with an inspection door 15, and the inspection door 15 is equipped with a handle 18.

[0019] The method using the aforementioned ultra-high performance concrete flowability testing device includes the following steps: A. Prepare a series of ultra-high performance concrete slurries with different spread. Use a mortar mixer 3 to perform low-speed mixing for 3 minutes, high-speed mixing for 2 minutes, pause for 1 minute, and high-speed mixing for 2 minutes in sequence. During the second high-speed mixing, after the current stabilizes on the display screen 16, read the current value and measure the slurry spread. Plot a data curve based on the current value and the corresponding slurry spread to obtain the functional relationship between the current and the slurry spread. B. Determine the range of scalability values ​​for the ultra-high performance concrete based on the required workability of the ultra-high performance concrete. C. Substitute the current into the functional relationship between the current and the slurry spread based on the spread range value.， The current range value is calculated; D. Prepare ultra-high performance concrete and pour it into mortar mixer 3. Turn on circuit breaker 4. Set the mixing task mode through controller 7. Then turn on contactor 8 through control button 14 or controller 7. Perform low-speed mixing for 3 minutes, high-speed mixing for 2 minutes, pause delay for 1 minute and high-speed mixing for 2 minutes in sequence. During the second high-speed mixing, after the current stabilizes on display screen 16, read the current value. E. Determine whether the tested current value is within the calculated current value range. If the tested current value is not within the calculated current value range, then re-prepare the ultra-high performance concrete. Conversely, if the tested current value is within the calculated current value range, it means that the workability of the prepared ultra-high performance concrete meets the requirements. Further test its spreadability and carry out the next molding work.

[0020] The mortar mixer 3 can be a commercially available mortar mixer or a commonly used laboratory mortar mixer. It is used to fully mix ultra-high performance concrete slurry. By receiving instructions from the control box 1, it can perform different mixing speeds, mixing methods, and other operations to meet various process requirements in the slurry mixing process.

[0021] Control box 1 can be connected to a three-phase 380V AC power supply; a neutral wire is not required. The power supply is converted using a 380AC / 220AC transformer 12 to power controller 7, gateway 9, and other control circuits.

[0022] Aviation Line 2 is responsible for establishing a reliable electrical connection between the control box and the mixer, ensuring that control signals and power supply can be transmitted to the mixer stably and safely, and guaranteeing the normal operation of the entire equipment.

[0023] The controller 7 is a PLC controller with a programmable memory for storing instructions to perform logical operations, sequential control, timing, counting, and arithmetic operations. It controls the opening and closing of the contactor 8 via digital or analog input / output to select high-speed or low-speed mixing, thereby controlling the mixing process of the mortar mixer 3. In this embodiment, the mixing process is defined as four stages: low-speed mixing, high-speed mixing, pause delay, and high-speed mixing. The user can customize the time for each stage.

[0024] The contactor 8 can be manually operated directly via control button 14 to control the low-speed and high-speed mixing of the mortar mixer 3.

[0025] The display screen 16 is an HMI display screen, which is the interface for users to interact with the equipment. Users can observe the current operating current curve of the stirrer and set parameters through the display screen 16.

[0026] Gateway 9 enables remote diagnostics and maintenance of equipment. Controller 7 can upload experimental data to a cloud server for storage via gateway 9; simultaneously, remote devices can send commands to controller 7 via gateway 9, and relevant information can also be displayed on display screen 16.

[0027] The current and voltage detection sensor 17 detects the current and voltage of the mixer motor 20 during operation and sends the detection data to the controller 7, which is then displayed on the screen 16. This information can be used to indirectly calculate the torque of the mortar mixer blades 3.

[0028] A method for testing the spreadability of ultra-high performance concrete (UHVPC) utilizes the functional relationship between current magnitude and the spreadability of UHVPC slurry to rapidly evaluate the fluidity of the slurry. Based on this functional relationship, and considering the performance requirements of the UHVPC to be prepared, the slurry spreadability is first determined, and then the current range is calculated. During the concrete slurry mixing process, the spreadability of the slurry can be quickly estimated by monitoring the current magnitude in real time, thus achieving efficient evaluation of its fluidity. This provides timely and accurate data for adjusting the mix proportions and controlling the quality of UHVPC, helping to optimize concrete mix design, improve R&D efficiency, and ensure that the performance and quality of the final concrete product meet engineering application requirements.

[0029] The method includes the following steps: A. Prepare a series of ultra-high performance concrete slurries with different spreads. Using a mortar mixer 3, sequentially perform low-speed mixing (3 min), high-speed mixing (2 min), a pause delay (1 min), and high-speed mixing (2 min). In the fourth stage, after the current stabilizes on display 16, read the current value and measure the slurry spread. Based on the current value and the corresponding slurry spread data, plot a data curve (e.g., ...). Figure 3 As shown in the figure, the functional relationship between current and slurry spread is obtained: y = 1129.3 - 1032.3x, where x is the current (mA) and y is the spread of ultra-high performance concrete slurry (mm). B. Determine the range of scalability values ​​for the ultra-high performance concrete based on the required workability of the ultra-high performance concrete. C. Substitute the above functional relationship between current and slurry spread into the spread range value. ， The current range value is calculated; D. Prepare ultra-high performance concrete and pour it into mortar mixer 3. Turn on circuit breaker 4. Set the mixing task mode through controller 7. Then turn on contactor 8 through control button 14 or controller 7. Perform low-speed mixing (3min), high-speed mixing (2min), pause delay (1min) and high-speed mixing (2min) in sequence. After the current stabilizes on display screen 16, read the current value. E. If the tested current value is within the calculated current value range, it means that the workability of the prepared ultra-high performance concrete meets the requirements. Further test its spreadability and carry out the next molding work.

[0030] In this embodiment, three different mix proportions of ultra-high performance concrete were tested. Ultra-high performance concrete with the same mix proportion was mixed three times. The data are as follows: (a) UHPC (UC100) slurry spread test Test mix proportion (kg / m 3 As shown in Table 1, the predicted values ​​of UHPC slurry spread (i.e., the test results of the method of this invention) are compared with the actual test values ​​in Table 2.

[0031] Table 1

[0032] Table 2 Serial Number Actual current (mA) Predicted slurry spread (mm) Measured value of slurry spread (mm) 1 0.826 276 280 2 0.832 270 270 3 0.837 265 260 (II) UHPC (UC120) slurry spread test Test mix proportion (kg / m 3 As shown in Table 3, the predicted values ​​of UHPC slurry spread (i.e., the test results of the method of this invention) are compared with the actual test values ​​in Table 4.

[0033] Table 3

[0034] Table 4 Serial Number Actual current (mA) Predicted slurry spread (mm) Measured value of slurry spread (mm) 1 0.846 255 260 2 0.839 263 265 3 0.848 254 250 (III) UHPC (UC150) slurry spread test Test mix proportion (kg / m 3 As shown in Table 5, the predicted values ​​of UHPC slurry spread (i.e., the test results of the method of this invention) are compared with the actual test values ​​in Table 6.

[0035] Table 5

[0036] Table 6 Serial Number Actual current (mA) Predicted slurry spread (mm) Measured value of slurry spread (mm) 1 0.844 258 256 2 0.851 251 255 3 0.843 259 265 The test results above show that the predicted values ​​of the method of the present invention are basically consistent with the measured values.

Claims

1. A device for testing the spreadability of ultra-high performance concrete, characterized in that: The system includes a control box (1) and a mortar mixer (3). The control box (1) is equipped with a circuit breaker (4), a current and voltage detection sensor (17), a contactor (8), and a controller (7). The circuit breaker (4) is connected to an external power source via a power line (19). The circuit breaker (4) is connected to the contactor (8). The current and voltage detection sensor (17) is connected in series in the connection circuit between the circuit breaker (4) and the contactor (8). The contactor (8) is connected to the mixer motor (20) of the mortar mixer (3). The circuit breaker (4) is connected to the controller (7). A display screen (16) is provided on the surface of the control box (1). The controller (7) is connected to the current and voltage detection sensor (17), the contactor (8), and the display screen (16) respectively.

2. The ultra-high performance concrete scalability testing device according to claim 1, characterized in that: A control button (14) is provided on the surface of the control box (1), and the control button (14) is connected to the contactor (8).

3. A test device for the spreadability of ultra-high performance concrete according to claim 1 or 2, characterized in that: The control box (1) is equipped with a gateway (9), and the circuit breaker (4) is connected to the gateway (9). The gateway (9) is connected to the controller (7) and the display screen (16) respectively.

4. The ultra-high performance concrete spreadability testing device according to claim 3, characterized in that: The control box (1) is equipped with an inspection door (15).

5. A method for testing the spreadability of ultra-high performance concrete, characterized in that: Using the ultra-high performance concrete scalability testing device according to any one of claims 1-4, the method includes the following steps: A. Prepare a series of ultra-high performance concrete slurries with different expansion degrees, mix them with a mortar mixer (3), and after the current stabilizes on the display screen (16), read the current value and measure the slurry expansion degree. Based on the data of the current value and the corresponding slurry expansion degree, draw a data curve to obtain the functional relationship between the current and the slurry expansion degree. B. Determine the range of scalability values ​​for the ultra-high performance concrete based on the required workability of the ultra-high performance concrete. C. Substitute the current into the functional relationship between the current and the slurry spread based on the spread range value. ， The current range value is calculated; D. Prepare ultra-high performance concrete and pour it into the mortar mixer (3), turn on the circuit breaker (4), set the mixing task mode through the controller (7), then turn on the contactor (8), and read the current value after the current stabilizes on the display screen (16). E. Determine whether the tested current value is within the calculated current value range. If the tested current value is not within the calculated current value range, then re-prepare the ultra-high performance concrete. Conversely, if the tested current value is within the calculated current value range, it means that the workability of the prepared ultra-high performance concrete meets the requirements. Further test its spreadability and carry out the next molding work.

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