Concrete shrinkage testing device
By using an optical non-contact concrete shrinkage testing device, which utilizes light source projection, coordinate paper imaging, and data processing system, the automatic monitoring of concrete shrinkage is achieved. This solves the problems of time-consuming, labor-intensive, and error-prone traditional methods, and improves measurement efficiency and accuracy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-30
- Publication Date
- 2026-04-07
AI Technical Summary
Existing methods for measuring concrete shrinkage require multiple manual interventions, which are time-consuming, labor-intensive, and prone to reading errors. Furthermore, traditional contact-based measurements may introduce mechanical stress interference, resulting in higher costs.
By employing light source projection and coordinate paper magnification imaging technology, combined with a high-definition camera and data processing and analysis system, we can achieve automated monitoring of concrete shrinkage. We can acquire specimen deformation data through optical non-contact methods and maintain a stable experimental environment using a temperature and humidity control system.
It improves measurement efficiency and accuracy, reduces manual intervention and costs, eliminates mechanical stress interference, and significantly improves the measurement accuracy of minute deformations.
Smart Images
Figure CN224095746U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of concrete shrinkage measurement, specifically a concrete shrinkage testing device. Background Technology
[0002] The shrinkage phenomenon caused by volume changes during the hardening process of concrete not only affects the dimensional stability of the structure but may also lead to cracking, reduced durability, and safety issues. Concrete shrinkage is mainly classified into plastic shrinkage, drying shrinkage, autogenous shrinkage, carbonation shrinkage, and temperature shrinkage. Based on the timing and conditions of shrinkage, concrete shrinkage can be divided into early shrinkage (including plastic shrinkage and autogenous shrinkage, mainly occurring in the early stages after concrete pouring), mid-stage shrinkage (mainly caused by cement hydration reaction, usually occurring in the middle of concrete hardening), and late-stage shrinkage (caused by drying shrinkage and carbonation shrinkage, usually occurring in the later stages of concrete hardening). The formation mechanism of these shrinkage phenomena involves multiple factors such as the physicochemical properties of concrete, material composition, construction technology, and environmental conditions, making it an important indicator for evaluation.
[0003] Concrete shrinkage measurement experiments are an important means of evaluating concrete performance. Their main purpose is to understand the durability and stability of concrete by measuring its volume changes under different conditions. Commonly used experimental methods currently include contact and non-contact methods. The contact method uses a dial indicator or other contact sensors to directly measure the length change of the specimen. This method is suitable for determining the shrinkage of concrete specimens under constant temperature and humidity conditions, and its operation is relatively simple and low-cost. However, it requires manual measurement, reading, and recording at regular intervals (approximately every 3 days), which is not only time-consuming and labor-intensive but also susceptible to errors from human readings affecting the experimental results. Furthermore, changes in the environment are unavoidable during each specimen removal, placement, and observation process. The non-contact method uses optical or displacement sensors to monitor the deformation of the specimen in real time. While avoiding the errors that may arise from instrument-specimen contact in traditional contact methods, it significantly increases the cost of the experiment. Therefore, this invention proposes a shrinkage testing device that effectively improves measurement efficiency, reduces reading errors, and controls costs. Utility Model Content
[0004] The technical problem to be solved by this utility model is to provide a concrete shrinkage testing device to improve measurement efficiency and accuracy, reduce errors and lower costs.
[0005] The above-mentioned objectives of this utility model are achieved through the following technical solutions:
[0006] A concrete shrinkage testing device includes an environmental chamber, a temperature and humidity control system, a light source, graph paper, a high-definition camera, and a data processing and analysis system.
[0007] Both the light source and the graph paper are placed inside the environmental chamber; the graph paper is fixed on one side of the environmental chamber; the light source is fixed on the other side of the environmental chamber and is located on the opposite side of the graph paper.
[0008] The high-definition camera is fixed on one side of the environmental chamber and is located on the opposite side of the graph paper.
[0009] The temperature and humidity control system includes a temperature controller, a humidity controller, a temperature metal probe, a humidity probe, a cooling fan, a humidifier, and a heater; the temperature metal probe, humidity probe, cooling fan, humidifier, and heater are all installed inside the environmental chamber; the temperature controller is connected to the temperature metal probe, cooling fan, and heater respectively; the humidity controller is connected to the humidity probe and humidifier respectively; the temperature controller and humidity controller are both installed outside the environmental chamber.
[0010] The data processing and analysis system includes an image acquisition module, an image preprocessing module, a feature extraction module, a data analysis module, a report generation unit, and a display and output module. The high-definition camera is connected to the image acquisition module, the image acquisition module is connected to the image preprocessing module, the image preprocessing module is connected to the feature extraction module, the feature extraction module is connected to the data analysis module, the data analysis module is connected to the report generation unit, and the report generation unit is connected to the display and output module.
[0011] Furthermore, a photographic reflector is attached to the outer surface of the environmental chamber.
[0012] Compared with the prior art, the present invention has the following advantages:
[0013] (1) Avoid the drawbacks of traditional methods that require multiple manual interventions, further simplify the experimental process, and reduce labor and time costs.
[0014] (2) Eliminate the data loss caused by interval measurement in traditional methods. The image data is magnified several times before analysis, which significantly improves the measurement accuracy. It is especially suitable for the study of concrete performance that is sensitive to small deformations.
[0015] (3) By using light source projection and coordinate paper magnification imaging technology, there is no need for physical contact with the specimen. This eliminates the mechanical stress interference that may occur with contact. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the overall structure of a concrete shrinkage testing device according to the present invention.
[0017] Figure 2 This is a schematic diagram of the environmental chamber of a concrete shrinkage testing device according to the present invention;
[0018] Figure 3 A schematic diagram of the temperature and humidity control system of a concrete shrinkage testing device according to a utility model.
[0019] Figure 4 This is a schematic diagram of the data processing and analysis system for a concrete shrinkage testing device, which is a utility model.
[0020] 1-Photographic reflector, 2-Temperature and humidity control system, 3-Environmental chamber, 4-Light source, 5-Graphic paper, 6-High-definition camera, 7-Data processing and analysis system, 8-Temperature controller, 9-Humidity controller, 10-Temperature metal probe, 11-Humidity probe, 12-Refrigeration fan, 13-Humidifier, 14-Heater. Detailed Implementation
[0021] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings.
[0022] like Figure 1 , 2 As shown, this utility model discloses a concrete shrinkage testing device, comprising an environmental chamber 3, a temperature and humidity control system 2, a light source 4, graph paper 5, a high-definition camera 6, and a data processing and analysis system 7. The light source 4 and graph paper 5 are both housed inside the environmental chamber 3. The graph paper 5 is fixed to one side of the environmental chamber 3, and the light source 4 is fixed to the other side of the environmental chamber 3, located opposite the side containing the graph paper. The high-definition camera 6 is fixed to one side of the environmental chamber 3, located opposite the side containing the graph paper.
[0023] like Figure 3 As shown, the temperature and humidity control system 2 includes a temperature controller 8, a humidity controller 9, a temperature metal probe 10, a humidity probe 11, a cooling fan 12, a humidifier 13, and a heater 14. The temperature metal probe 10, humidity probe 11, cooling fan 12, humidifier 13, and heater 14 are all located inside the environmental chamber 3. The temperature controller 8 is connected to the temperature metal probe 10, cooling fan 12, and heater 14 respectively. The humidity controller 9 is connected to the humidity probe 11 and humidifier 13 respectively. Both the temperature controller 8 and humidity controller 9 are located on the outside of the environmental chamber 3. The temperature and humidity inside the environmental chamber 3 are controlled by the temperature and humidity control system 2. During operation, the start and stop temperatures of the cooling fan 12 and heater 14, as well as the start and stop humidity of the humidifier 13, are first set using the temperature controller 8 and humidity controller 9. Then, the temperature metal probe 10 and humidity probe 11, placed inside the environmental chamber, sensitively measure the temperature and humidity inside the environmental chamber to control the start and stop of the corresponding devices, thereby achieving temperature and humidity control.
[0024] like Figure 4As shown, the data processing and analysis system 7 includes an image acquisition module, an image preprocessing module, a feature extraction module, a data analysis module, a report generation unit, and a display and output module; the high-definition camera is connected to the image acquisition module, the image acquisition module is connected to the image preprocessing module, the image preprocessing module is connected to the feature extraction module, the feature extraction module is connected to the data analysis module, the data analysis module is connected to the report generation unit, and the report generation unit is connected to the display and output module.
[0025] The image acquisition module is responsible for receiving real-time video streams from high-definition cameras, converting them into digital signals, and dividing them into consecutive image frames according to timestamps, providing raw data for subsequent processing.
[0026] The image preprocessing module performs noise reduction, geometric correction, and binarization on the original image to eliminate environmental interference and extract clear coordinate paper grids and test block projection edges. The key processing steps are: first, using a Gaussian filtering algorithm for noise reduction to eliminate noise caused by ambient light fluctuations while preserving edge details; then, based on perspective transformation technology, inputting reference point coordinates, and automatically correcting coordinate paper distortion caused by light source tilt; next, enhancing image contrast, primarily improving the contrast between grid lines and test block projections to avoid overexposure or underexposure; and finally, performing binarization segmentation.
[0027] The feature extraction module can identify the reference grid on the coordinate paper, track the displacement of the projected edge of the test block, and optimize sub-pixel values. It can automatically match the intersection points of the coordinate paper grid, establish an initial coordinate system, track the displacement of the projected edge of the test block, and finally output Δx and Δy.
[0028] The data analysis module primarily calculates the concrete shrinkage rate based on displacement data, generates a time-shrinkage rate curve, and stores the results. The shrinkage rate is calculated using the following formula:
[0029]
[0030] L0: Initial length of the specimen (unit: mm); ΔL(t): Shrinkage of the specimen (unit: mm)
[0031] In conventional calculations, only the initial distance in the x-direction (lateral direction) is typically taken as L0; correspondingly, Δx is taken as ΔL(t), which meets the requirements of traditional shrinkage measurement. This device can also add calculations to output the initial distance in the y-direction as L0 and Δy as ΔL(t).
[0032] The results display and output module visualizes the shrinkage rate curve, generates experimental reports, and supports data export. The dynamic chart in the visualization function is a real-time line graph: the horizontal axis represents time, and the vertical axis represents the shrinkage rate.
[0033] The workflow of the data processing and analysis system 7 is as follows: First, the image acquisition module collects raw data from the video stream of the high-definition camera. Second, the image preprocessing module performs noise reduction and correction, and the output value is then sent to the data analysis module via the feature extraction module; the data analysis module calculates the shrinkage rate and outputs the result in real time. Third, the report generation unit exports the data to the display and output module to form a real-time curve. The video stream changes as follows: video file → preprocessing → binarized image → displacement tracking → shrinkage rate calculation → real-time curve.
[0034] As a further preferred option, the outer surface of the environmental chamber 3 is covered with a photographic reflector 1 (black on the outside and white on the inside), such as... Figure 1 As shown, it is used to enhance the illumination effect of the light source.
[0035] The working process of the concrete shrinkage testing device of this utility model is as follows:
[0036] In operation, the concrete test specimen is placed in an environmental chamber. The required temperature and humidity are set using the temperature and humidity control system. The light source is adjusted to a suitable position, the high-definition camera is turned on, and the relevant parameters are set on the data processing and analysis system. After the test is completed, clicking "start" will automatically begin the experiment. Light from the light source illuminates the concrete specimen, creating a magnified image on graph paper. The high-definition camera captures and records this image, transmitting the image and video data to the data processing and analysis system. The system processes the transmitted image and video data, calculates the concrete shrinkage rate, and plots it on a graph.
[0037] This invention relates to a concrete shrinkage testing device. A concrete specimen is placed in an environmental chamber with controlled temperature and humidity. A light source illuminates the specimen, creating a magnified image on coordinate paper placed within the chamber. A high-definition camera captures the position of the coordinate axes of the image, and this coordinate data is simultaneously transmitted to a data processing and analysis system for image data processing to derive the deformation result, thus improving measurement efficiency. The environmental chamber's temperature and humidity control system maintains stable environmental conditions during the experiment, avoiding the environmental variation errors caused by the need to move the specimen for each measurement, as in traditional methods. The high-definition camera allows for observation at any time of day and in any weather condition. Furthermore, the data processing and analysis system enables automated monitoring and calculation, solving the time-consuming and labor-intensive problems of traditional experimental methods. Additionally, for cases of minute deformation that are difficult to observe, the data processing and analysis system can save and magnify the images several times, making the data more accurate and reliable.
Claims
1. A concrete shrinkage testing device, characterized in that: Includes an environmental chamber, a temperature and humidity control system, a light source, graph paper, a high-definition camera, and a data processing and analysis system; Both the light source and the graph paper are placed inside the environmental chamber; the graph paper is fixed on one side of the environmental chamber; the light source is fixed on the other side of the environmental chamber and is located on the opposite side of the graph paper. The high-definition camera is fixed on one side of the environmental chamber and is located on the opposite side of the graph paper. The temperature and humidity control system includes a temperature controller, a humidity controller, a temperature metal probe, a humidity probe, a cooling fan, a humidifier, and a heater; the temperature metal probe, humidity probe, cooling fan, humidifier, and heater are all installed inside the environmental chamber; the temperature controller is connected to the temperature metal probe, cooling fan, and heater respectively; the humidity controller is connected to the humidity probe and humidifier respectively; the temperature controller and humidity controller are both installed outside the environmental chamber. The data processing and analysis system includes an image acquisition module, an image preprocessing module, a feature extraction module, a data analysis module, a report generation unit, and a display and output module. The high-definition camera is connected to the image acquisition module, the image acquisition module is connected to the image preprocessing module, the image preprocessing module is connected to the feature extraction module, the feature extraction module is connected to the data analysis module, the data analysis module is connected to the report generation unit, and the report generation unit is connected to the display and output module.
2. The concrete shrinkage testing device according to claim 1, characterized in that: The outer surface of the environmental chamber is covered with a photographic reflector.