A thermal response-based lightweight aggregate concrete uniformity detection device

Abstract

The utility model relates to light aggregate concrete homogeneity detection equipment technical field, concretely to a light aggregate concrete homogeneity detection device based on heat response, including heat -insulating container, has the cavity of placing, heating plate is set up in the bottom of heat -insulating container, and with the lower surface of heat -insulating container is pasted, heat preservation casing, coaxial setting in the outer peripheral surface of heat -insulating container, multiple temperature sensor, setting in the outer peripheral surface of heat -insulating container, data collector, setting in one side of heat preservation casing, and multiple temperature sensor all with data collector electricity is connected, host computer, setting in one side of data collector, with data collector electricity is connected. The device adds constant heat flow through heat -insulating container bottom heating plate, gathers each layer temperature data by side wall temperature sensor, judges whether light aggregate is floated and separated with the difference of heating rate, realizes nondestructive, in situ, real -time detection, and precision is high, cost is low, and the project applicability is strong.

Description

Technical Field

[0001] This utility model relates to the technical field of lightweight aggregate concrete uniformity testing equipment, specifically a lightweight aggregate concrete uniformity testing device based on thermal response. Background Technology

[0002] Lightweight aggregate concrete refers to concrete made by replacing ordinary crushed stone with lightweight coarse aggregates such as expanded clay, pumice, and expanded perlite. It possesses excellent properties such as lightweight, high strength, thermal insulation, sound insulation, and earthquake resistance. With the rapid development of my country's construction industry and the acceleration of infrastructure construction, lightweight aggregate concrete is widely used in high-rise buildings, long-span bridges, special structures, and various non-load-bearing and load-bearing structures, becoming an important development direction in the building materials industry.

[0003] However, because the apparent density of lightweight aggregate is much lower than that of cement paste, it is prone to floating and segregation during mixing, pouring, and vibration, which deteriorates the mechanical and durability properties of concrete. Therefore, the homogeneity testing of the mixture is the key to quality control. Currently used image analysis methods, stratification test methods, density mass method, ultrasonic testing method, and CT scanning method have drawbacks such as destructive sampling, large operational errors, susceptibility to environmental interference, and expensive equipment that is difficult to apply on site. Therefore, there is an urgent need for a non-destructive, in-situ, real-time, easy-to-operate, and low-cost lightweight aggregate concrete homogeneity testing device. Utility Model Content

[0004] (a) Technical problems to be solved In order to overcome the above-mentioned defects of the prior art, this utility model provides a thermal response-based lightweight aggregate concrete uniformity detection device, which solves the problems of destructive detection, large operational error, significant environmental interference, high equipment cost, and inability to detect in real time on site mentioned in the background art.

[0005] (II) Technical Solution To achieve the above objectives, this utility model provides the following technical solution: a device for detecting the uniformity of lightweight aggregate concrete based on thermal response, comprising: Insulated container with a placement cavity; A heating plate is disposed at the bottom of the heat insulation container and is attached to the lower surface of the heat insulation container; An insulated shell is coaxially disposed on the outer peripheral surface of the heat-insulating container; Multiple temperature sensors are disposed on the outer peripheral surface of the insulated container; A data acquisition unit is disposed on one side of the insulation shell, and multiple sets of temperature sensors are electrically connected to the data acquisition unit; The host computer is located on one side of the data acquisition device and is electrically connected to the data acquisition device.

[0006] Preferably, multiple sets of temperature sensors are arranged in a circular array along the outer peripheral surface of the insulation container, each set of temperature sensors includes at least five, and the at least five temperature sensors in the same set are arranged sequentially from top to bottom along the axial direction of the insulation container.

[0007] Preferably, the outer peripheral surface of the heat insulation container has multiple sets of blind holes, and each set of blind holes is corresponding to a set of temperature sensors. Each temperature sensor is embedded in the corresponding blind hole, and the bottom wall of the blind hole is 1mm to 2mm away from the inner peripheral surface of the heat insulation container.

[0008] Preferably, the inner circumferential surface of the heat insulation shell is provided with a plurality of positioning blocks, and the plurality of positioning blocks are provided in a one-to-one correspondence with the plurality of blind holes. Each positioning block is embedded in the corresponding blind hole and is attached to the side of the temperature sensor away from the blind hole.

[0009] Preferably, the upper end of the heat-insulating container is detachably connected to an insulation cover, and the upper end of the insulation cover is fixedly connected to a handle.

[0010] Preferably, a battery is provided on one side of the insulation shell, and the battery is electrically connected to the heating plate, temperature sensor, data acquisition unit and host computer respectively.

[0011] Preferably, the heating power of the heating plate is 50W to 100W.

[0012] (III) Beneficial Effects This invention provides a device for detecting the uniformity of lightweight aggregate concrete based on thermal response, which has the following advantages: This thermal response-based device for detecting the uniformity of lightweight aggregate concrete utilizes the significant difference in thermal conductivity between lightweight aggregate and cement paste. A constant surface heat source is applied to the bottom of an insulated container via a heating plate, allowing heat to flow vertically upwards. Multiple temperature sensors on the outer surface of the insulated container transmit the data to a host computer via a data acquisition unit. The host computer fits the stable linear segments of the temperature-time curves at each measuring point to calculate the heating rate of each layer. By comparing the differences in heating rates between layers, it determines whether lightweight aggregate has undergone segregation. If the heating rates of each layer are basically the same, the aggregate distribution is considered uniform; if the heating rate at the bottom is significantly higher than at the top, aggregate segregation is considered. Compared with existing technologies, this device can achieve non-destructive testing without requiring specimen preparation. By performing cutting or destructive treatment, the same specimen can be repeatedly tested, overcoming the shortcomings of image analysis, density method, and stratification barrel method, which require destroying the specimen. It can also be tested after the specimen is cast, without additional sample preparation or post-processing of images. This overcomes the shortcomings of existing methods that rely on post-processing and cannot be evaluated in real time. At the same time, it improves the accuracy and reliability of the test. It is based on a clear thermal conductivity physical model and is not affected by appearance factors such as concrete color and aggregate shape. It overcomes the shortcomings of large operation error of stratification barrel method and low accuracy of ultrasonic method. It also reduces the test cost and improves the applicability of engineering. The device has a simple structure and does not require expensive CT scanning equipment or complex ultrasonic testing instruments. It is low in cost and easy to promote and use in engineering sites. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the exploded structure of this utility model; Figure 2 This is a schematic diagram of the overall structure of this utility model; Figure 3 This is a cross-sectional structural diagram of the present invention; Figure 4 This is a schematic diagram of the thermal insulation shell structure of this utility model.

[0014] In the diagram: 1. Insulated container; 2. Heating plate; 3. Insulated shell; 4. Temperature sensor; 5. Data acquisition unit; 6. Host computer; 7. Blind hole; 8. Positioning block; 9. Insulated cover plate; 10. Handle; 11. Battery. Detailed Implementation

[0015] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0016] Example 1: Please refer to Figures 1 to 4This utility model provides a technical solution: a thermal response-based device for detecting the uniformity of lightweight aggregate concrete, comprising an insulated container 1 with a placement cavity; a heating plate 2 disposed at the bottom of the insulated container 1 and attached to the lower surface of the insulated container 1; an insulation shell 3 coaxially disposed on the outer circumferential surface of the insulated container 1; multiple sets of temperature sensors 4 disposed on the outer circumferential surface of the insulated container 1; a data acquisition unit 5 disposed on one side of the insulation shell 3, and all sets of temperature sensors 4 are electrically connected to the data acquisition unit 5; and a host computer 6 disposed on one side of the data acquisition unit 5 and electrically connected to the data acquisition unit 5. The heating power of the heating plate 2 is 50W to 100W.

[0017] The above technical solution uses a placement cavity inside the insulated container 1 to accommodate lightweight aggregate concrete samples, providing a sealed sample space for testing. The heating plate 2 provides an active and controllable heat excitation source for the entire testing device. The insulation shell 3 further blocks heat exchange between the side wall of the insulated container 1 and the external environment, minimizing lateral heat loss and forcing heat flow to be conducted only vertically in one dimension. This ensures that the temperature changes collected by the temperature sensors 4 at each height are caused only by differences in the internal thermal conductivity of the concrete, rather than by lateral heat loss, thereby improving testing accuracy. Multiple temperature sensors 4 collect real-time data on the temperature and time changes of the concrete at different heights, providing raw data support for the host computer 6 to calculate the heating rate of each layer and compare the differences in heating rates, thereby determining whether the lightweight aggregate has undergone segregation.

[0018] The data acquisition unit 5 synchronously receives and records the temperature and time data collected by all temperature sensors 4. After performing analog-to-digital conversion and preliminary processing on the signals, it transmits them to the host computer 6. It should be noted that the data acquisition unit 5 is a multi-channel data acquisition module, and its number of channels is not less than the number of temperature sensors 4. The sampling frequency of the data acquisition unit 5 is 1 to 10 times per second. The host computer 6 can be, for example, a computer, tablet computer, or dedicated data processing terminal, which is equipped with data acquisition and processing software to display the temperature and time curves of each measuring point in real time. It also uses the least squares method to perform linear fitting on the linear segment of each curve where the temperature rise is stable, calculates the heating rate of each measuring point, and then compares the maximum relative difference of the heating rate of each layer. When the difference is less than a preset threshold, it is determined that the lightweight aggregate is uniformly distributed. When the difference is greater than or equal to the preset threshold, it is determined that the lightweight aggregate has floated and segregated. At the same time, the host computer 6 is also used to store the detection data and output the detection results.

[0019] In this embodiment, the sidewall of the heat insulation container 1 is made of a cylindrical structure using a material with low thermal conductivity. The material can be PVC or polytetrafluoroethylene, with a thermal conductivity ≤0.2 W / (m²). K), the bottom wall of the heat insulation container 1 is made of thermally conductive metal material with a thickness of 3mm to 5mm. The bottom wall and the side wall are sealed together. The heating plate 2 is a circular flat plate heater with an outer diameter that matches the outer diameter of the heat insulation container 1. The heating power is 50W to 100W. The heating plate 2 can be equipped with a PID temperature control module to maintain a constant heating power. It should be noted that those skilled in the art can make equivalent substitutions or adjustments to the above parameters and materials without departing from the concept of this device.

[0020] Please see Figure 1 and Figure 3 Multiple sets of temperature sensors 4 are arranged in a ring array along the outer peripheral surface of the insulation container 1. Each set of temperature sensors 4 includes at least five sensors. The at least five temperature sensors 4 in the same set are arranged sequentially from top to bottom along the axial direction of the insulation container 1. Multiple sets of blind holes 7 are opened on the outer peripheral surface of the insulation container 1. The multiple blind holes 7 are arranged one-to-one with the multiple sets of temperature sensors 4, and each temperature sensor 4 is embedded in the corresponding blind hole 7. The bottom wall of the blind hole 7 is 1mm to 2mm away from the inner peripheral surface of the insulation container 1. A battery 11 is provided on one side of the insulation shell 3. The battery 11 is electrically connected to the heating plate 2, the temperature sensors 4, the data acquisition device 5 and the host computer 6 respectively.

[0021] In the above technical solution, temperature sensors 4 are arranged sequentially from top to bottom along the axial direction of the insulation container 1, respectively located at the bottom, lower middle, middle, upper middle, and top of the insulation container 1, for real-time detection of the temperature at different locations of the insulation container 1. The bottom of the blind hole 7 is 1mm to 2mm away from the inner circumferential surface of the insulation container 1 and does not penetrate the side wall of the container. Its function is to provide positioning space for the temperature sensor 4 to be embedded and installed, so that the temperature sensing surface of the temperature sensor 4 can be close to the inner wall of the insulation container 1 and indirectly collect the concrete temperature through the thin wall. At the same time, since the blind hole 7 does not penetrate the side wall, the inner wall of the insulation container 1 remains intact and smooth, and there is no need to set a sealing ring, which fundamentally eliminates the possibility of concrete mixture leaking from the installation location of the temperature sensor 4. The risk of grout leakage is eliminated, ensuring the integrity of the sample and the airtightness of the testing environment. At the same time, a heat-conducting medium can be placed on the temperature sensing surface of the temperature sensor 4 to make it fit tightly against the bottom of the blind hole 7, thereby enhancing the heat conduction efficiency between the temperature sensing surface and the bottom of the blind hole 7, reducing contact thermal resistance and temperature measurement lag, and further improving the accuracy and response speed of temperature detection. The battery 11 provides an independent and portable power supply for all electrical components of the entire testing device, freeing the device from dependence on external power sources. It can operate independently in environments lacking stable external power sources, such as concrete mixing plants, precast component factories, and construction sites, greatly improving the portability, mobility, and on-site applicability of the device, and truly realizing in-situ real-time detection.

[0022] In addition, the temperature sensor 4 can be, by way of example, a Pt100 platinum resistance thermometer or a T-type thermocouple.

[0023] Please see Figure 3 and Figure 4 The inner circumferential surface of the heat insulation shell 3 is provided with multiple positioning blocks 8, and the multiple positioning blocks 8 are respectively set with multiple blind holes 7. Each positioning block 8 is embedded in the corresponding blind hole 7 and is attached to the side of the temperature sensor 4 away from the blind hole 7. The upper end of the heat insulation container 1 is detachably connected to the heat insulation cover plate 9, and the upper end of the heat insulation cover plate 9 is fixedly connected to the handle 10.

[0024] In the above technical solution, multiple positioning blocks 8 are embedded in corresponding blind holes 7 and are tightly fitted to the side of the temperature sensor 4 opposite to the bottom of the blind hole 7. Their function is to apply radial positioning pressure to the temperature sensor 4 from the outside, firmly pressing the temperature sensor 4 against the bottom of the blind hole 7. This ensures that the temperature sensing surface of the temperature sensor 4 and the bottom wall of the blind hole 7 remain tightly fitted through the heat-conducting medium, preventing gaps from forming between the sensor and the bottom of the blind hole 7 due to vibration, thermal expansion and contraction, or loose installation. This ensures the accuracy, stability, and repeatability of temperature acquisition. The insulation cover plate 9 is made of insulation material, and its function is to seal the top of the insulation container 1 after the sample is poured, reducing the contact between the upper surface of the concrete sample and the external environment. The heat exchange between the environment reduces heat loss at the top, making the heat flow field more uniform and stable in the vertical direction. This avoids the abnormally low heating rate at the top measuring point due to heat loss at the top, which could lead to misjudgment as the floating and segregation of lightweight aggregate, thus ensuring the accuracy of the test results. The detachable design facilitates sample pouring, vibration, and cleaning. The handle 10 provides a handhold for the operator to apply force, which facilitates the operator to quickly pick up, open, and align the insulation cover 9. Especially in the process of adding insulation after sample pouring and removing the sample after testing, the handle 10 can improve the convenience and safety of operation, avoiding burns or damage from direct contact with the insulation cover 9.

[0025] In this invention, the working steps of the device are as follows: First, during use, open the insulation cover 9 using the handle 10, pour the well-mixed lightweight aggregate concrete mixture into the placement cavity of the insulation container 1, compact it with vibration, and then quickly close the insulation cover 9 to seal the top of the sample and reduce heat exchange between the upper surface and the external environment. Then, the battery 11 supplies power to the heating plate 2, temperature sensor 4, data acquisition unit 5, and host computer 6. The heating plate 2 actively heats the bottom of the insulation container 1 with a constant power of, for example, 50W. The heat is transferred to the interior of the concrete sample through the thermally conductive metal bottom wall, and under the combined insulation effect of the insulation shell 3 and the insulation cover 9, the heat flow is forced to conduct only vertically upwards in one dimension. Simultaneously, the temperature sensor 4, embedded in the corresponding blind hole 7, collects the real-time temperature of the concrete at the corresponding height. The positioning block 8... Temperature sensor 4 is firmly pressed against the bottom of blind hole 7 on the outside. Multiple temperature sensors 4 transmit temperature signals from different heights and circumferential positions to data acquisition unit 5 synchronously. Data acquisition unit 5 performs analog-to-digital conversion and preliminary processing on all channel signals and transmits them to host computer 6 in real time. Host computer 6 displays the temperature and time curves of each measuring point in real time through data acquisition and processing software. It also performs linear fitting of the linear segment of each curve with stable temperature rise using the least squares method to calculate the heating rate of each measuring point. Then, it compares the maximum relative difference of the heating rate of each layer. When the difference is less than the preset threshold, it is determined that the lightweight aggregate is uniformly distributed. When the difference is greater than or equal to the preset threshold, it is determined that the lightweight aggregate has floated and segregated. At the same time, host computer 6 stores all detection data and outputs the final detection results.

[0026] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for detecting the uniformity of lightweight aggregate concrete based on thermal response, characterized in that, include: Insulated container (1), having a placement cavity; A heating plate (2) is disposed at the bottom of the heat insulation container (1) and is attached to the lower surface of the heat insulation container (1); The heat-insulating shell (3) is coaxially disposed on the outer peripheral surface of the heat-insulating container (1); Multiple temperature sensors (4) are disposed on the outer circumferential surface of the heat-insulating container (1); The data acquisition unit (5) is located on one side of the heat insulation shell (3), and multiple sets of temperature sensors (4) are electrically connected to the data acquisition unit (5); The host computer (6) is located on one side of the data acquisition unit (5) and is electrically connected to the data acquisition unit (5).

2. The device for detecting the uniformity of lightweight aggregate concrete based on thermal response according to claim 1, characterized in that: Multiple sets of temperature sensors (4) are arranged in a ring array along the outer peripheral surface of the heat insulation container (1). Each set of temperature sensors (4) includes at least five sensors, and the at least five temperature sensors (4) in the same set are arranged sequentially from top to bottom along the axial direction of the heat insulation container (1).

3. The device for detecting the uniformity of lightweight aggregate concrete based on thermal response according to claim 2, characterized in that: The outer circumferential surface of the heat insulation container (1) is provided with multiple sets of blind holes (7), and the multiple blind holes (7) are respectively arranged in correspondence with multiple sets of temperature sensors (4), and each temperature sensor (4) is embedded in the corresponding blind hole (7). The bottom wall of the blind hole (7) is 1mm to 2mm away from the inner circumferential surface of the heat insulation container (1).

4. The device for detecting the uniformity of lightweight aggregate concrete based on thermal response according to claim 3, characterized in that: The inner circumferential surface of the heat insulation shell (3) is provided with a plurality of positioning blocks (8), and the plurality of positioning blocks (8) are provided one-to-one with the plurality of blind holes (7). Each positioning block (8) is embedded in the corresponding blind hole (7) and is attached to the side of the temperature sensor (4) away from the blind hole (7).

5. The device for detecting the uniformity of lightweight aggregate concrete based on thermal response according to claim 1, characterized in that: The upper end of the heat insulation container (1) is detachably connected to a heat insulation cover plate (9), and the upper end of the heat insulation cover plate (9) is fixedly connected to a handle (10).

6. The device for detecting the uniformity of lightweight aggregate concrete based on thermal response according to claim 1, characterized in that: A battery (11) is provided on one side of the heat-insulating shell (3). The battery (11) is electrically connected to the heating plate (2), temperature sensor (4), data acquisition device (5) and host computer (6).

7. The device for detecting the uniformity of lightweight aggregate concrete based on thermal response according to claim 1, characterized in that: The heating power of the heating plate (2) is 50W to 100W.

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