A system and method for online monitoring of comprehensive concrete working performance

Abstract

This disclosure provides an online monitoring system for the comprehensive workability of concrete, comprising: a concrete diversion device located on the concrete transport line between the mixing plant and the construction site; a testing container located below it for collecting concrete and testing its workability, the container having multiple interconnected testing channels at its bottom; a gate assembly for controlling the flow of concrete between the channels; a sensing unit for measuring the concrete mass in the testing container and the concrete level in each testing channel; a data processing and equipment control terminal for controlling the gate assembly, calculating a series of concrete indicators based on the data measured by the sensing unit, using these as test results, and providing alarms for abnormal test results, as well as storing and transmitting measurement data and test results; and a cloud platform for communicating with the data processing and equipment control terminal. This disclosure enables online in-situ monitoring, rapid evaluation, and alarm feedback of multiple workability parameters of concrete without affecting on-site pouring construction.

Description

Technical Field

[0001] This disclosure belongs to the field of concrete workability testing technology, and specifically relates to an online monitoring system and method for the comprehensive workability of concrete. Background Technology

[0002] Concrete is one of the most widely used building materials. It is made by mixing water, cement, fly ash, sand and gravel aggregates, and admixtures in a certain proportion. Concrete that is still in a plastic flow state after mixing is called self-compacting concrete. The workability of self-compacting concrete is directly related to the uniformity and compactness of the concrete after pouring and molding, which in turn has a significant impact on the construction quality and service life of the engineering structure. The main workability properties of self-compacting concrete include: fluidity (plasticity), viscosity, uniformity, gap passage, and density. National, industry, local, and group standards all have specific regulations and methods for testing and evaluating the workability of concrete mixtures.

[0003] However, relying on existing methods to test the workability of self-compacting concrete has the following problems:

[0004] (1) Existing testing methods and techniques require a specialist to manually conduct multiple tests to obtain a comprehensive performance evaluation, which is not only time-consuming and labor-intensive, but also the validity and reliability of the results depend on the skill level of the test personnel.

[0005] (2) Existing automated testing methods and devices for concrete workability are mostly independent of the concrete mixing, production and transportation process. They cannot be organically integrated with the existing concrete production-transportation system. Forcing them to be integrated may interfere with and affect on-site construction.

[0006] (3) Due to limitations in testing methods, the comprehensive testing of concrete workability can only be carried out on-site by taking timed sampling tests (usually once every 4 / 8 hours). The testing efficiency and frequency are low, making it difficult to reflect the true workability of concrete.

[0007] (4) Due to the variability of the raw materials themselves, the workability of self-compacting concrete on site is always dynamic. There is a lack of real-time online quantitative detection methods, making it difficult to carry out real-time alarm feedback and dynamic adjustment, and the workability of concrete is not guaranteed.

[0008] To address the aforementioned issues, based on the principles of diversion detection and aggregate recycling, this invention proposes an online monitoring system and method for the comprehensive workability of concrete. This system enables online, automatic, rapid, and comprehensive detection, evaluation, and alarm feedback of the comprehensive workability of concrete on-site without affecting on-site construction. It solves the current problems of low efficiency and frequency of concrete workability testing, weak representativeness of test results, inability to provide real-time alarms and dynamic feedback, high manpower and material costs, and poor result stability. Summary of the Invention

[0009] This disclosure aims to address at least one of the technical problems in the related art.

[0010] The present disclosure provides an online monitoring system and method for the comprehensive workability of concrete, which can realize automated online in-situ monitoring, rapid evaluation and alarm feedback of multiple workability of concrete without affecting on-site pouring construction, and provide real-time feedback to guide concrete mixing and production and mix proportion adjustment.

[0011] To achieve the above objectives, the present disclosure adopts the following technical solution:

[0012] The first aspect of this disclosure provides an online monitoring system for the comprehensive workability of concrete, comprising:

[0013] A concrete diversion device is located on the concrete transport line between the batching plant and the construction site, and is used to guide part or all of the concrete for workability testing.

[0014] A testing container, located below the concrete diversion device, is used for collecting concrete and testing its workability. The testing container has multiple testing channels that are interconnected at the bottom. One of the testing channels serves as a feeding channel, through which the concrete diverted by the concrete diversion device enters the testing container.

[0015] The aggregate collection equipment, located below the testing container, is used to collect the tested concrete discharged from the testing container and transport it to the construction site.

[0016] The gate assembly is used to control the flow of concrete between different passages during the operation of the online monitoring system.

[0017] The sensing unit is used to measure the mass of the concrete in the detection container and the liquid level of the concrete in each detection channel in the detection container.

[0018] The data processing and equipment control terminal is used to control the gate group; calculate a series of indicators of concrete based on the data measured by the sensing unit, as the comprehensive workability test result of concrete, and perform an alarm for abnormal comprehensive workability test result of concrete, as well as store and send the measurement data and test results. The series of indicators includes any combination of multiple indicators among the fluidity, viscosity, uniformity and apparent density of concrete.

[0019] Equipment bracket, used for installing and arranging the concrete diversion device, the detection container, the gate group, the sensing unit and the data processing and equipment control terminal;

[0020] The cloud platform communicates with the data processing and equipment control terminal to archive, analyze, and push alarms on the measurement data or detection results transmitted by the data processing and equipment control terminal, and sends the archived data and alarm information to the user terminal on a timed or event-based basis according to user needs.

[0021] In some embodiments, the concrete diversion device includes a diversion storage container, a diversion channel, a diversion discharge port, an overflow channel, and an overflow return channel;

[0022] The diversion channel connects the fresh concrete unloading channel or unloading point located near the online monitoring system to the upper part of the diversion storage container. The fresh concrete prepared by the mixing plant is transported to the fresh concrete unloading channel or unloading point via a chute or concrete mixer truck.

[0023] The overflow channel is used to discharge concrete exceeding the volume limit in the drainage storage container and transport it to the aggregate equipment through the overflow return channel. The overflow return channel is also used to transport concrete that has not been tested, which is transported by the fresh concrete unloading channel or unloading point, to the aggregate equipment.

[0024] The discharge port is connected between the feed channel of the discharge storage container and the detection container.

[0025] In some embodiments, the volume limit is 0.8 to 1.2 times the amount of concrete required for a single test of the testing container; the inclination angle α of the overflow channel is 30° to 80°; the upper part of the discharge port is set in a gradually narrowing form, the inclination angle γ is not less than 50°, and the minimum side length of the cross-section of the discharge port is not less than 5 times the maximum aggregate particle size of the concrete.

[0026] The material storage container is also equipped with an inclined isolation screen that is connected to the overflow channel to prevent unevenly mixed concrete lumps from entering the material discharge port. The aperture of the isolation screen is 3 to 10 times the maximum aggregate size of the concrete, and the inclination angle β of the isolation screen is 20° to 50°.

[0027] In some embodiments, the interior of the testing container is divided into several testing channels by several partitions, the spacing between the partitions is adjustable, the minimum side length of the cross-section of any testing channel is not less than 5 times the maximum aggregate size of the concrete, and the height is not less than 10 times the maximum aggregate size of the concrete; one of the testing channels located on the outermost side or in the middle of the testing container is selected as the feeding channel, and the cross-sectional area of ​​the feeding channel is not less than 1.5 times that of the other testing channels.

[0028] In some embodiments, the bottom of the testing container is provided with a testing discharge port, which consists of an inclined section that gradually narrows and a parallel extension section connected to its lower part. The inclination angle θ of the inclined section is 40° to 70°, the cross-section of the testing discharge port is circular or regular polygonal, the diameter of the parallel extension section is not less than 5 times the maximum aggregate size of the concrete, and the length of the parallel extension section is not less than 3 times the maximum aggregate size of the concrete.

[0029] In some embodiments, the gate assembly includes a diversion gate at the inlet of the concrete diversion device, a feed gate at the outlet of the concrete diversion device for controlling the amount of concrete loaded into the testing container, and a discharge gate at the discharge outlet of the testing container. When the testing container is in the feeding stage, the discharge gate remains closed, and the feed gate remains open. When the amount of concrete in the testing container reaches a set value, both the discharge gate and the feed gate remain closed, and the testing container is in a static stage. When the concrete level in each testing channel of the testing container tends to remain constant, the testing container enters the discharge stage, the discharge gate is opened, and the feed gate remains closed. The diversion gate is normally open during the testing process and is closed only when the current batch of concrete is not being tested.

[0030] In some embodiments, the sensing unit includes a weight sensor and a liquid level measurement component; the weight sensor is disposed at the bottom of the detection container; the liquid level measurement component is a liquid level sensor group or an image recognition module, the liquid level sensor group consists of multiple liquid level sensors, each of which is disposed directly above a corresponding detection channel in the detection container; the image recognition module acquires images of each detection channel by adding scale lines to the transparent outer wall of each detection channel and using a camera, and uses an image recognition algorithm to measure the height of the concrete liquid level.

[0031] In some embodiments, the sensing unit further includes a temperature sensor mounted on the inner or outer wall of the detection container for monitoring the temperature at the concrete outlet.

[0032] In some embodiments, the data processing and device control terminal calculates the concrete fluidity index I based on the concrete liquid level height in each detection channel of the detection container at the start of unloading, collected by the sensing unit. f and apparent density ρ c0 Based on the concrete quality data collected by the sensing unit during the unloading stage of the detection container, a concrete unloading quality-time curve is obtained, and the viscosity index I of the concrete is calculated. v and uniformity index UI c .

[0033] In some embodiments, the data processing and equipment control terminal calculates the concrete fluidity index I according to the following formula. f and apparent density ρ c0 :

[0034]

[0035] in, To measure the concrete liquid level in each detection channel at the start of unloading, k is the detection channel number, k = 1 to K, K is the number of detection channels in the container, and f() is the quantitative relationship between the flowability index and the liquid level in each detection channel established based on theoretical calculations and laboratory tests; V equ To detect the internal volume of the container, S k Let be the cross-sectional area of ​​the k-th detection channel. Let the height be the upper edge height of the k-th detection channel. This refers to the distance from the concrete liquid level in each testing channel to the upper edge of each testing channel.

[0036] The data processing and equipment control terminal calculates the viscosity index I of the concrete according to the following formula. v :

[0037]

[0038] in, Let t1 be the average unloading rate during the uniform unloading period, and t1 and m1 be the initial time and initial unloading mass of the uniform unloading period, respectively. n and m n , respectively, represent the last time and the last unloading mass during the uniform unloading period, and g() represents the quantitative relationship between the viscosity index and the average unloading rate established based on theoretical calculations and indoor experiments;

[0039] The data processing and equipment control terminal uses any one of the following three formulas to calculate the uniformity index UI of the concrete. c :

[0040]

[0041] Where, m i and m i+1 These represent the concrete unloading masses at the i-th and i+1-th recorded values ​​during the uniform unloading period, respectively, t. i and t i+1 These are the times for the i-th and i+1-th recorded values ​​during the uniform unloading period, respectively. This is an estimate of the concrete unloading mass at the time corresponding to the i-th recorded value. The fitting formula is obtained by linearly fitting the data of the uniform unloading period in the concrete unloading mass-time curve: Calculate the estimated value.

[0042] In some embodiments, a barrier steel bar is provided in the feeding channel to detect the gap passage index of concrete. The data processing and equipment control terminal determines whether the feeding channel is blocked based on the liquid level height of the concrete in the feeding channel collected by the sensing unit, and calculates the gap passage index according to the following formula:

[0043]

[0044] Where, δ pass This is an index for the permeability of gaps in concrete.

[0045] In some embodiments, the online monitoring system further includes an alarm device installed at the mixing plant;

[0046] The alarm push types of the cloud platform are divided into concrete workability abnormality alarm and equipment abnormality alarm; the alarm push of the cloud platform adopts a probability risk mechanism. When an abnormality is detected and the risk probability is greater than the design threshold, an alarm reminder is sent through the user terminal and the alarm device.

[0047] A second aspect of this disclosure provides an online monitoring method for an online monitoring system according to any embodiment of the first aspect of this disclosure, comprising the following steps:

[0048] Step S1: Before the mixing plant starts producing concrete, the sensing unit is first zeroed, and the inner wall of the detection container and its connecting pipe is moistened with clean water.

[0049] Step S2: When the mixing plant produces concrete, the data acquisition and equipment control terminal is turned on to initialize the opening and closing status of the gate group. Part or all of the fresh concrete delivered by the mixing plant enters the detection container, and the concrete that does not enter the detection container enters the aggregate equipment.

[0050] Step S3: The sensing unit records in real time the mass m of the concrete to be tested entering the detection container and the liquid level height of the concrete in each detection channel. And transmit it to the data acquisition and equipment control terminal;

[0051] Step S4: When the concrete mass m in the detection container is greater than the mass threshold m0, or the concrete liquid level in the feeding channel reaches the set height threshold, close all the gates in the gate group and let it stand for a period of time to allow the concrete liquid level in each detection channel to tend to remain constant. This is taken as the initial state before unloading, and the concrete liquid level in each detection channel at this time is recorded. and the quality of concrete inside the testing container m c0 ;

[0052] Step S5: The detection container is unloaded through the gate assembly, and the mass m(t) of the concrete to be tested in the detection container and the liquid level of the concrete in each detection channel are recorded in real time by the sensing unit during the unloading process. t represents time;

[0053] Step S6: After all the concrete in the detection container has been discharged, the data acquisition and equipment control terminal, based on the data recorded by the sensing unit... and m c0 Calculate the flowability index I of concrete f and apparent density ρ c0 Based on the m(t) measurement curve during the unloading process measured by the sensing unit, the viscosity index I of the concrete is calculated. v and uniformity index UI c The calculated performance indicators, along with the measurement data collected by the sensing unit, are uploaded to the cloud platform as test results.

[0054] Step S7: The cloud platform archives, analyzes, and pushes alarms on the data uploaded by the data acquisition and device control terminal, and the results are pushed to the user terminal in real time.

[0055] Step S8: If the on-site pouring is not yet completed, return to step S2 and continue with the next concrete test; if the on-site pouring is completed, clean the test container and wait for the next start-up test.

[0056] Compared with the prior art, this disclosure has the following characteristics and beneficial effects:

[0057] (1) This disclosure can obtain quantitative indicators of various working properties of concrete mixtures such as fluidity (plasticity), cohesiveness, anti-segregation, gap passage and uniformity in a single test, and these indicators can be used to supplement each other. For example, when the unloading time is too long, the working properties of the concrete can be accurately inferred based on its unloading uniformity and gap passage, and it can be applied to different types of concrete.

[0058] (2) The structure of this disclosure is simple and flexible, and can realize online automatic unmanned monitoring of concrete workability.

[0059] (3) This disclosure can be integrated with the concrete production process to achieve real-time detection, rapid evaluation and alarm feedback of the workability of concrete mixtures without interfering with construction, and real-time feedback to guide the mixing and production of concrete.

[0060] (4) This invention is simple and fast. A single test and evaluation takes 2 to 5 minutes. 96 to 240 tests can be conducted per shift (8 hours), which far exceeds the number of tests specified in the current standards. It can better reflect the true working performance of concrete mixtures.

[0061] (5) This disclosure can measure various work performance indicators of concrete such as fluidity (plasticity), cohesiveness, segregation resistance, gap passage and uniformity at one time, and they can be interpreted in a complementary manner; for example, when the unloading time is too long, the workability of concrete can be accurately inferred based on its unloading uniformity and gap passage. Attached Figure Description

[0062] Figure 1 This is a schematic diagram of the overall structure of an online monitoring system for the comprehensive workability of concrete provided in the first aspect of this disclosure;

[0063] Figure 2 yes Figure 1 Side and top views of the concrete diversion device in the online monitoring system shown;

[0064] Figure 3 yes Figure 1 The diagram shows the detection principle of the container in the online monitoring system.

[0065] Figure 4 The second aspect of this disclosure provides an embodiment based on Figure 1 A flowchart of the online monitoring method of the monitoring system shown.

[0066] Figure 5 The monitoring curves obtained in this embodiment show the concrete quality in the testing container during the feeding, settling, and unloading processes, and the distance from the concrete liquid level in each testing channel to the upper edge of the testing container. Detailed Implementation

[0067] To make the objectives, technical solutions, and advantages of this application clearer, the application will be described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application.

[0068] Conversely, this application covers any alternatives, modifications, equivalent methods, and schemes made within the spirit and scope of this application as defined by the claims. Furthermore, to provide the public with a better understanding of this application, certain specific details are described in detail below. However, this application can be fully understood by those skilled in the art even without these detailed descriptions.

[0069] See Figure 1 , Figure 2The first aspect of this disclosure provides an online monitoring system for the comprehensive workability of concrete, comprising:

[0070] Concrete diversion device 1 is located on the concrete transport line between the mixing plant and the construction site, and is used to guide part or all of the concrete for workability testing.

[0071] The testing container 2 is located below the concrete diversion device 1 and is used for collecting concrete and testing its workability. The testing container 2 has multiple testing channels with interconnected bottoms inside. One of the testing channels serves as the feeding channel 21, through which the concrete diversion device 1 draws the concrete into the testing container 2.

[0072] The aggregate collection device 10, located below the testing container 2, is used to collect the tested concrete discharged from the testing container 2 and transport it to the construction site.

[0073] Gate assembly 3 is used to control the flow of concrete between various passages during the operation of the online monitoring system in this embodiment;

[0074] Sensing unit 4 is used to measure the mass of concrete in the detection container 2 and the liquid level of concrete in each channel of the detection container 2.

[0075] The data processing and equipment control terminal 5 is connected to the gate group 3 and the sensing unit 4 and is used to control the gate group 3; calculate a series of concrete indicators based on the data measured by the sensing unit 4, which are used as the comprehensive workability test results of concrete and to issue an alarm for abnormal comprehensive workability test results of concrete, as well as store and send the measurement data and test results. The series of indicators includes any combination of multiple indicators among the fluidity, viscosity, uniformity and apparent density of concrete.

[0076] Equipment bracket 6 is used to install and arrange concrete diversion device 1, detection container 2, gate group 3, sensing unit 4 and data processing and equipment control terminal 5;

[0077] The cloud platform 7 communicates with the data processing and equipment control terminal 5 to archive, analyze, and push alarms on the measurement data or test results transmitted by the data processing and equipment control terminal 5, and sends the archived data and alarm information to the user terminal on time or by event according to user needs.

[0078] In some embodiments, the equipment support 6 is a frame structure composed of several components. Each component of the frame structure is preferably made of rust-resistant, sturdy, and easy-to-clean alloy material and is connected and fastened by bolting for easy disassembly. The equipment support 6 is provided with fixed positions for the concrete diversion device 1, the detection container 2, the gate group 3, the sensing unit 4, and the data processing and equipment control terminal 5. The equipment support 6 is preferably an independent, ground-separated integral form for easy hoisting and movement.

[0079] In some embodiments, see Figure 2The concrete diversion device 1 includes a diversion and storage container 12, an isolation screen 15 disposed inside the diversion and storage container 12, diversion channels 11, diversion discharge ports 13, and overflow channels 14 connected to the upper, lower, and side parts of the diversion and storage container 12, and an overflow return channel 16 connected to the collection device 3. The diversion channels 11 guide part or all of the concrete transported from the fresh concrete unloading channel or unloading point located near the online monitoring system of this embodiment into the diversion and storage container 12. The fresh concrete prepared by the mixing plant is transported to the fresh concrete unloading channel or unloading point via a chute or concrete mixer truck. The diversion and storage container 12 collects and stores a portion of the concrete during the testing process, awaiting the next test, while also avoiding interference with the testing process and results. Overflow channel 14 is used to discharge concrete exceeding the volume limit in the drainage storage container 12 and transport it to the collection equipment 10 through overflow return channel 16, avoiding pollution and waste caused by concrete overflow. Overflow return channel 16 is also used to transport concrete that was not used in this test from the fresh concrete unloading channel or unloading point to the collection equipment 10. The aforementioned volume limit is usually taken as 0.8 to 1.2 times the amount of concrete required for a single test of the test container 2, so as to ensure that there is sufficient concrete for each test. The inclination angle α of overflow channel 14 is 30° to 80° to avoid concrete clogging in overflow channel 14. The discharge port 13 is connected between the lower part of the discharge storage container 12 and the upper part of the feed channel 21 inside the detection container 2. The upper part of the discharge port 13 is set to gradually narrow, with an inclination angle γ of not less than 50°. According to practical experience, if the inclination angle γ < 45°, when the concrete viscosity is high, it is easy to cause wall hanging, which causes the concrete to accumulate in the discharge port 13, eventually leading to blockage of the discharge port 13 and affecting the normal operation of the equipment. The minimum side length of the cross-section of the discharge port 13 is not less than 5 times the maximum aggregate particle size of the concrete. The isolation screen 15 is inclinedly set inside the drainage and storage container 12, mainly to block the unevenly mixed concrete lumps and guide them back to the overflow return channel 16 through the overflow channel 14, so as to avoid blockage of the test container 2 and fluctuation of the test results. The aperture setting of the isolation screen 15 should be determined according to the concrete type and mix ratio. Generally, it should be set to 3 to 10 times the maximum aggregate particle size of the concrete to be tested, so as to avoid excessively large aggregates or concrete lumps entering the test container 2 and affecting the test results. The inclination angle β of the isolation screen 15 (i.e., the angle between the isolation screen 15 and the horizontal plane) should be set to 20° to 50° so that the excessively large aggregates or concrete lumps screened out are discharged from the drainage and storage container 12 in the set direction.

[0080] In some embodiments, the testing container 2 is a multi-channel interconnected container with a connected bottom. The main body of the testing container is made of a rust-resistant, robust, and easy-to-clean alloy material or a transparent material, such as a transparent acrylic sheet, to facilitate visualization of the testing process. The interior of the testing container 2 is divided into several interconnected testing channels by several partitions. The number K of testing channels, the size of the testing channels, the volume of the testing container, and the specific structure should be determined according to the type of concrete to be tested and the volume of a single test. Several slots are formed on the inner wall of the testing container 2 to cooperate with the partitions. By inserting the partitions into different slots, the width of the testing channels can be adjusted to adapt to different types of concrete. The minimum side length of the cross-section of any testing channel is not less than 5 times the maximum aggregate size of the concrete, and the height is not less than 10 times the maximum aggregate size of the concrete. For self-compacting concrete with good fluidity, the test channels can be set into a narrow and long form by adjusting the arrangement of the baffles. The number of channels can be 4 to 8, and the cross-sectional size of the channel is 5 to 8 times the maximum aggregate size of the concrete, generally 8cm to 16cm. For ordinary concrete with poor fluidity, the test channels can be set into a wider form by adjusting the arrangement of the baffles. The number of test channels can be 3 to 5, and the cross-sectional size of the test channel is 5 to 10 times the maximum aggregate size of the concrete, generally 10cm to 20cm.

[0081] Furthermore, the outermost or middle detection channel within the detection container 2 is generally designated as the feed channel 21. The cross-sectional area of ​​the feed channel 21 is not less than 1.5 times that of other detection channels to prevent concrete blockage. A short baffle 22 should be added to the upper part of the feed channel 21 to prevent concrete splashing from affecting the readings of the sensor in the sensing unit 4 used to measure the concrete liquid level height within the channel. Since the cross-sectional area of ​​the feed channel 21 is larger than that of other detection channels, a barrier steel bar 23 can be installed within the feed channel 21 to detect the intermittent passage of concrete. The barrier steel bar 23 is positioned near the bottom of the feed channel 21, and the spacing between two adjacent barrier steel bars 23 is generally set to 2 to 3 times the maximum aggregate size of the concrete, typically 4 cm to 6 cm, to simulate a narrower filling or flow channel.

[0082] Furthermore, the bottom of the testing container 2 is provided with a testing discharge port 24, which adopts a gradually narrowing form. The inclination angle θ of the inclined section is 40° to 70°, and the cross-section of the testing discharge port 24 is circular or regular polygonal. A parallel extension section needs to be set at the lower end of the inclined section of the testing discharge port 24 to control the concrete discharge flow rate. The diameter of the parallel extension section is not less than 5 times the maximum aggregate size of the concrete, and can be set to 5 to 8 times the maximum aggregate size of the concrete. The length of the parallel extension section is not less than 3 times the maximum aggregate size of the concrete.

[0083] In some embodiments, the main function of the collecting device 10 is to recover the tested concrete discharged from the testing container 2, mix it with the concrete conveyed through the overflow return channel 16, and then transport it to the construction site. Depending on the conditions of the construction site, a pumping device or a hopper can generally be used as the collecting device 10.

[0084] In some embodiments, the gate assembly 3 includes: a diversion gate 31 disposed at the inlet of the diversion channel 11 in the concrete diversion device 1, which opens and closes to control whether concrete is diverted for testing by opening and closing the passage between the fresh concrete discharge channel or discharge point and the concrete diversion device 1; an inlet gate 32 disposed at the bottom of the diversion discharge port 13 in the concrete diversion device 1, which opens and closes to control the passage between the concrete diversion device 1 and the testing container 2 by opening and closing the gate, thereby automatically controlling the concrete testing and diversion; when the amount of concrete discharged into the testing container 2 reaches a certain value, the inlet gate 32 is closed to stop feeding; and a discharge gate 33 disposed at the bottom of the testing discharge port 24 in the testing container 2, which opens and closes to control the passage between the testing container 2 and the collecting device 3, thereby automatically controlling the loading and unloading. When the testing container 2 is in the feeding stage, the discharge gate 33 remains closed, and the feed gate 32 remains open. When the concrete in the testing container 2 reaches the set amount, both the discharge gate 33 and the feed gate 32 remain closed, and the testing container 2 is in the static stage. When the concrete level in each testing channel of the testing container 2 tends to remain constant, the testing container 2 enters the discharge stage, the discharge gate 33 is opened, and the feed gate 32 remains closed. The diversion gate 31 is normally open during the testing process and is only closed when the current batch of concrete is not involved in the testing. Each gate is preferably controlled by a pneumatic gate in conjunction with a solenoid valve, but electric gates and hydraulic gates are optional. Optionally, if the concrete has high viscosity or the aggregate particle size is large, a scraper arch breaker 8 can be installed above the feed gate 32 and the discharge gate 33. The blades inside the scraper arch breaker 8 rotate to prevent aggregate particle arches and concrete blockages from forming at the outlet of the concrete diversion device 1 and the testing container 2.

[0085] In some embodiments, the sensing unit 4 is used to collect relevant data in real time during the detection process according to the instructions of the data processing and equipment control terminal 5. The collected data mainly includes the concrete quality in the detection container 2 and the liquid level of the concrete in each detection channel. These data are automatically detected in real time by the weight sensor 41 and the liquid level sensor group 42, respectively. The weight sensor 41 is preferably a vibrating wire weight sensor, but it can also be a resistance strain gauge weight sensor or a capacitive weight sensor, and it is located at the bottom of the detection container 2. The liquid level sensor group 42 consists of multiple liquid level sensors, each of which is located directly above a corresponding detection channel in the detection container 2. It is preferably a laser rangefinder sensor, but it can also be an ultrasonic rangefinder sensor, an infrared rangefinder sensor, or a fiber optic rangefinder sensor. In addition, for the detection container 2 made of transparent material, an image recognition module can be used to replace the liquid level sensor group 42 to achieve automatic detection of the liquid level in each detection channel. Specifically, the image recognition module adds scale lines to the outer wall of each detection channel, combines them with a camera to acquire images of each detection channel, and uses an image recognition algorithm to measure the concrete liquid level.

[0086] Furthermore, the sensing unit 4 also includes a temperature sensor installed on the inner or outer wall of the detection container 2 to detect the concrete outlet temperature, so as to provide feedback and guide the mixing plant personnel to adjust the concrete outlet temperature. The concrete outlet temperature is related to the peak temperature of the concrete and the subsequent cracking risk. When the concrete outlet temperature is too high, ice can be added during mixing to reduce the concrete outlet temperature and avoid cracking caused by excessive concrete temperature. When the concrete outlet temperature is too low, an alarm is issued in time to avoid pouring quality problems caused by poor fluidity of concrete at low temperature.

[0087] Combination Figure 3 The detection principle of detection container 2 is explained as follows:

[0088] The fluidity (plasticity) of freshly mixed concrete is directly related to its yield stress τ0. Under the influence of gravity, friction from side walls (including the side walls and partition surfaces of the testing container), and viscous resistance, the filling height varies in different connected channels. Specifically, when the concrete is subjected to pressure P, gravity G, and shear yield resistance F... τ0 When the sums are equal, the concrete will stop rising within the channel, and the shear yield resistance F... τ0The yield stress τ0 and the contact area between the concrete and the sidewall are positively correlated. Therefore, the better the concrete's fluidity, the smaller the yield stress τ0, and the higher the filling height of the concrete in the channel; conversely, the worse the concrete's fluidity, the greater the yield stress, and the lower the filling height of the concrete in the channel. Thus, the difference in filling height between different channels directly reflects the magnitude of the yield stress τ0, i.e., the magnitude of the concrete's fluidity (plasticity). The higher the concrete's fluidity, the smaller the yield stress τ0 that its self-weight flow needs to overcome, and the smaller the filling height difference between the liquid surfaces; conversely, the lower the fluidity, the larger the filling height difference between the liquid surfaces. Considering the complex influence and randomness brought about by the multiphase nature of concrete (aggregate, mortar, air), a quantitative relationship between the concrete fluidity index and the channel liquid surface height difference can be determined by combining theoretical calculations and indoor experiments. It should be noted that the purpose of setting multiple detection channels in this embodiment is: 1) to make the differences in detection results more significant, i.e., to increase the filling height difference; 2) to eliminate the influence of the concrete's own velocity or kinetic energy on the results.

[0089] Furthermore, based on the height of the concrete within the testing channel, the volume of the concrete can be calculated, and combined with its mass, the apparent density of the freshly mixed concrete can be deduced.

[0090] Furthermore, the viscosity and segregation resistance of concrete can be evaluated based on the unloading time or rate of concrete; the quantitative relationship between concrete viscosity index and unloading rate of test container can be determined by relying on laboratory tests.

[0091] Furthermore, the uniformity of fresh concrete is evaluated based on the fluctuation and uniformity of the concrete unloading rate. The smaller the fluctuation of the unloading rate during the unloading process and the smoother the curve of the unloading mass changing with time, the more uniform the unloading process is, which means that the uniformity and workability of the concrete are better. Conversely, the more complex and tortuous the curve of the unloading mass changing with time, the worse the uniformity of the concrete is.

[0092] Furthermore, the clearance of the concrete is determined by whether it can pass smoothly through the testing container 2 and its built-in reinforcing steel bars 23.

[0093] In some embodiments, the data processing and equipment control terminal 5 is responsible for processing various sensor data and automatically controlling the gate; the data processing and equipment control terminal 5 is equipped with a network port or 4G module, which can upload the collected measurement data and detection results to the cloud platform 6 via wired or wireless means; wherein, the data processing and equipment control terminal 5 calculates the concrete fluidity index I based on the concrete liquid level height in each detection channel collected by the sensing unit 4 at the initial moment of unloading of the detection container 2. f and apparent density ρ c0Based on the concrete quality data collected by sensor unit 4 during the unloading process of detection container 2, the concrete unloading quality-time curve is obtained, and the viscosity index I of the concrete is calculated. v and uniformity index UI c .

[0094] Furthermore, the data processing and equipment control terminal 5's processing of various sensors and gate control includes: collecting data from various sensors at a certain frequency (which can be remotely controlled via cloud platform 7), including data from weight sensor 41 and liquid level sensor group 42 or image recognition module; performing operations such as anomaly removal and performance index calculation on the collected measurement data, and simultaneously uploading the data to cloud platform 7 via wired or wireless network for data archiving and push; and automatically controlling the gate opening and closing according to a given operation procedure to achieve automatic material feeding detection and unloading. The specific process by which the data processing and equipment control terminal 5 calculates the concrete performance index is as follows:

[0095] The data processing and equipment control terminal 5 judges the fluctuation of the measurement data of the liquid level sensor group 42. When the measurement data of the liquid level sensor group 42 or the image recognition module tends to stabilize, that is, no longer changes, it is used as the liquid level height of the concrete in each channel of the detection container 2 at the beginning of unloading. The fluidity index I of the concrete is calculated based on the liquid level height. f and apparent density ρ c0 The calculation process is as follows:

[0096] Based on the concrete liquid level height measured at the start of unloading in each channel and the fluidity index I established based on theoretical calculations and laboratory tests. f The quantitative relationship f() between the liquid level and the liquid level in each detection channel is used to deduce the concrete's fluidity index I. f :

[0097]

[0098] in, To detect the concrete level in each channel of container 2 at the start of unloading, k is the channel number, k = 1 to K, and K is the number of detection channels in container 2. Furthermore, slump spread can be used as a flowability indicator to determine f().

[0099] The mass m of concrete inside container 2 was measured at the start of unloading. c0 and concrete volume V c0 Calculate the apparent density ρ of concrete c0 :

[0100]

[0101] Among them, Vequ To detect the internal volume of container 2, S k Let be the cross-sectional area of ​​the k-th detection channel. Let the height be the upper edge height of the k-th detection channel. This refers to the distance from the concrete surface in each testing channel to the upper edge of each testing channel.

[0102] Viscosity index I of concrete v Related to the average unloading rate, the data processing and equipment control terminal 5 obtains the average unloading rate based on the measured concrete unloading mass-time curve. And the viscosity index I established based on theoretical calculations and indoor experiments v With average unloading rate The quantitative relationship g() between the two can be used to deduce the viscosity index I of concrete. v :

[0103]

[0104] It should be noted that when calculating the average unloading rate... When unloading, the starting and ending sections should be removed to eliminate the impact of accelerated concrete flow during the opening section and wall adhesion during the closing section on the unloading process. The intermediate section during unloading should be selected as the uniform unloading period, and the average unloading rate should be calculated using data from the uniform unloading period. Calculations were performed, and the data for the uniform unloading period were recorded when the concrete unloading volume reached between 5% and 15% of the total volume, and between 85% and 95%. Viscosity index I. v Specifically, you can choose the V-funnel discharge time, apparent viscosity, or Vebe consistency.

[0105] Furthermore, the average unloading rate of concrete is calculated according to the following formula.

[0106]

[0107] Where t1 and m1 are the initial time and initial unloading mass of the uniform unloading period, respectively. n and m n These represent the last time and the final discharge mass during the uniform discharge period, respectively.

[0108] Data processing and equipment control terminal 5 calculates the uniformity index of concrete (UI). c Similarly, data from the uniform unloading period are used. The uniformity index UI of the concrete is calculated using any of the following three methods. c :

[0109] Method 1: Calculate the uniformity index UI of concrete using the following formula. c :

[0110]

[0111] Where, m i and m i+1 These represent the concrete unloading masses at the i-th and i+1-th recorded values ​​during the uniform unloading period, respectively, t. i and t i+1 t1 and m1 represent the times at the i-th and i+1-th recorded values ​​during the uniform unloading period, respectively; t1 and m1 represent the initial time and initial unloading mass of the uniform unloading period, respectively. n and m n These represent the last time and the final discharge mass during the uniform discharge period, respectively.

[0112] It should be noted that the advantage of method one is that it does not require fitting calculations; the uniformity index UI can be obtained through simple calculations. c When the ability to perform fitting calculations is available, either method two or method three can also be used for calculation.

[0113] Method 2: Calculation method based on root mean square (RMS) of residuals

[0114] First, a linear fit was performed on the data during the uniform unloading period in the concrete unloading mass-time curve to obtain the fitting formula:

[0115]

[0116] in, t is an estimate of the concrete unloading mass, t is any moment in the uniform unloading period, and a and b are the coefficients and constant term of the linear fitting, respectively.

[0117] Then, the uniformity index UI of the concrete is calculated according to the following formula. c :

[0118]

[0119] in, It is an estimate of the concrete unloading mass at the time corresponding to the i-th recorded value;

[0120] Method 3: Calculation based on the discriminant coefficient (R-squared)

[0121] The uniformity index UI of concrete is calculated based on the above fitting formula and the following formula. c :

[0122]

[0123] in, It is the average mass of concrete unloaded during the uniform unloading period.

[0124] Furthermore, based on the batch test results of different types of concrete, this embodiment sets: when UI c A value >0.85 indicates good concrete homogeneity; a value >0.75 indicates good homogeneity. <UI c When the concrete viscosity is ≤0.85, it is considered slightly uneven; when it is ≤0.60, it is considered slightly uneven. <UI c When UI is ≤0.75, the concrete homogeneity is considered poor; when UI c A UI value ≤ 0.60 indicates severe concrete heterogeneity. For example, in the case of self-compacting concrete used in the construction of a dam, concrete with good homogeneity has a measured UI value of... c =0.96, UI measured for concrete with poor homogeneity c =0.67. It should be noted that when establishing... At that time, the uniformity index UI needs to be removed. c Data points <0.85 were used to eliminate interference and influence of phenomena such as concrete segregation and blockage on the above relationships.

[0125] Data processing and equipment control terminal 5 calculates the concrete gap passability index δ pass At that time, the judgment is made by checking whether there is a blockage at the obstacle steel reinforcement:

[0126]

[0127] Whether a blockage has occurred can be determined by the concrete level in the feed channel 21. Not exceeding the liquid level height threshold At that time, δ pass =1 indicates that the concrete has good gap passage; when the concrete liquid level in the feed channel 21 is high Exceeding the liquid level height threshold At that time, δ pass =0 indicates poor gap passage in the concrete; liquid level height threshold It is necessary to calculate based on the geometric dimensions of the testing container 2.

[0128] It is understood that the data processing and equipment control terminal 5 of this disclosure embodiment achieves the following four functions: (1) Calculates and evaluates the workability indicators of concrete based on the detection data of the sensing unit 4, including but not limited to the fluidity, viscosity, uniformity, segregation resistance, gap permeability, temperature and apparent density of concrete; (2) Controls the opening and closing of the gate group 3 to realize automatic feeding, automatic detection and automatic unloading of concrete workability testing, thereby realizing unmanned and automated testing; (3) Issues an alarm for abnormal concrete workability test results, and provides feedback to guide construction personnel to adjust and re-examine the concrete mix ratio to ensure the quality of concrete mixing; (4) Stores and sends test data and test results to provide a basis for the evaluation of engineering construction quality and the tracing of problems.

[0129] In some embodiments, the cloud platform 7 is mainly used for organizing and archiving the measurement data and detection results uploaded by the data processing and equipment control terminal 5. When the detection result I... f , I v UI c ρ c0 and δ pass In case of an anomaly, the cloud platform 7 promptly pushes alarm information to the user terminals, including the user's mobile terminal 9 and the computer in the mixing plant. Alarm push types are divided into two categories: concrete workability anomaly alarms and equipment anomaly alarms. Workability anomalies include: abnormal flowability alarms, abnormal viscosity alarms, abnormal uniformity alarms, abnormal apparent density alarms, and abnormal gap passage alarms. Equipment anomaly alarms include network anomaly alarms, gate control anomaly alarms, and concrete blockage alarms. When equipment malfunctions, the diversion gate 31 is automatically closed, and the infeed gate 32 and discharge gate 33 are opened to ensure that no new concrete is introduced into the online monitoring system, and that rainwater and flushing water do not accumulate in the concrete diversion device 1 and the detection container 2, preventing complete equipment blockage and affecting maintenance.

[0130] Furthermore, the online monitoring system of this embodiment also includes an alarm installed at the mixing plant. When the data processing and equipment control terminal 5 determines that the workability of the concrete is abnormal, the alarm flashes and sounds a buzzer to remind on-site and mixing plant personnel to pay attention to the concrete status, in order to adapt to the reality of noisy site, strong light, and sometimes inconvenient viewing of mobile terminal 9.

[0131] Furthermore, the alarm push of the cloud platform 7 adopts a probabilistic risk mechanism. When any of the above indicators exceeds the design threshold and the risk probability is greater than the design threshold, an alarm will be triggered through the mobile terminal 9 and the alarm device to remind on-site personnel to make feedback and adjustments.

[0132] See Figure 4The second aspect of this disclosure provides a method for online monitoring of the comprehensive workability of concrete based on the above-mentioned online monitoring system, comprising the following steps:

[0133] Step S1: Before the mixing plant starts producing concrete, the sensing unit 4 is first zeroed, and the inner walls of the concrete diversion device 1, the detection container 2 and the auxiliary diversion channel are moistened with clean water.

[0134] Step S2: When the mixing plant produces concrete, turn on the data acquisition and equipment control terminal 5 and initialize the opening and closing status of the gate group 3; when testing is required, open the diversion gate 31 and the feeding gate 32, close the unloading gate 33, and enter the feeding process. Guide some or all of the concrete through the diversion channel 11 into the concrete diversion device 1 and the testing container 2. The concrete flows in the testing container 2 by its own weight and gradually fills each testing channel.

[0135] Step S3: The sensing unit 4 records in real time the mass m of the concrete entering the detection container 2 and the liquid level of the concrete in each detection channel. And transmit it to the data acquisition and equipment control terminal 5;

[0136] S4. When the concrete mass m in the detection container 2 is greater than the mass threshold m0, or the concrete liquid level in the feed channel 21 reaches the set height threshold, close the feed gate 32 and keep the discharge gate 32 closed. Let it stand for a period of time, such as 40-120 seconds, so that the concrete liquid level in each detection channel tends to remain constant. This is taken as the initial state before discharge, and the concrete liquid level in each detection channel is recorded at this time. and the concrete quality m in container 2 c0 ;

[0137] S5. Open the unloading gate 33 and keep the inlet gate 32 closed to begin unloading the concrete from the detection container 2. The sensor unit 4 records in real time the concrete mass m(t) in the detection container 2 and the liquid level of the concrete in each detection channel during the unloading process. t represents time; see also Figure 5 , is the monitoring curve of the concrete quality and the distance from the concrete liquid surface in each detection channel to the upper edge of the detection container 2 during the process of feeding, settling to unloading, measured by the sensing unit 4;

[0138] S6. After all the concrete in the container 2 to be tested has been discharged, the data acquisition and equipment control terminal 5, based on the data recorded by the sensing unit 4, performs the following steps: and m c0 Calculate the flowability index I of concrete f and apparent density ρ c0Based on the m(t) monitoring curve measured by sensor unit 4 during the unloading process, the viscosity (anti-segregation) index I of the concrete is calculated. v Uniformity index (UI) c Gap passability index δ pass The working performance indicators, along with the measurement data collected by the sensing unit 4, are used as test results and uploaded to the cloud platform 7.

[0139] S7 and cloud platform 7 perform data archiving, data analysis and alarm push on the data uploaded by data acquisition and equipment control terminal 5, and the results will be pushed to the user terminal in real time.

[0140] S8. If the on-site pouring is not completed, return to step S2 and continue with the next section concrete test; if the on-site pouring is completed, close the diversion gate 31 and open the feed gate 32 and discharge gate 33 to ensure that no new concrete is diverted into the online monitoring system and that rainwater, flushing water, etc. do not accumulate in the concrete diversion device 1 and the test container 2; then use a high-pressure water gun to clean the test container 2 and wait for the next start-up test.

[0141] In summary, this embodiment of the invention can calculate the yield stress of concrete based on the concrete liquid level in each detection channel of the detection container, thereby determining its fluidity; it can calculate the uniformity of concrete discharge based on the discharge mass-time curve during the discharge process from the detection container; when the discharge is basically uniform, the viscosity of the concrete can be calculated based on the average discharge rate; when the feeding channel is equipped with obstruction reinforcement, the gap passage of the concrete can be determined by whether blockage occurs during the feeding and discharging process; in addition, the apparent density can be calculated based on the volume and mass of the concrete in the detection zone 2 at the start of discharging; thus, the fluidity, uniformity, viscosity, gap passage, and apparent density of concrete can be detected through a single feeding and discharging process; furthermore, if a temperature sensor is provided, the current temperature of the concrete can also be monitored. This invention is simple and fast and can be integrated with the concrete production process, enabling real-time detection, rapid evaluation, and alarm feedback of the workability of concrete mixtures without interfering with construction, providing real-time feedback to guide the mixing and production of concrete.

[0142] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0143] Although embodiments of this disclosure have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this disclosure, the scope of which is defined by the claims and their equivalents.

Claims

1. An online monitoring system for the comprehensive workability of concrete, characterized in that, include: A concrete diversion device is located on the concrete transport line between the batching plant and the construction site, and is used to guide part or all of the concrete for workability testing. A testing container, located below the concrete diversion device, is used for collecting concrete and testing its workability. The testing container has multiple testing channels that are interconnected at the bottom. One of the testing channels serves as a feeding channel, through which the concrete diverted by the concrete diversion device enters the testing container. The aggregate collection equipment, located below the testing container, is used to collect the tested concrete discharged from the testing container and transport it to the construction site. The gate assembly is used to control the flow of concrete between different passages during the operation of the online monitoring system. The sensing unit is used to measure the mass of the concrete in the detection container and the liquid level of the concrete in each detection channel in the detection container. The data processing and equipment control terminal is used to control the gate group; calculate a series of indicators of concrete based on the data measured by the sensing unit, as the comprehensive workability test result of concrete, and perform an alarm for abnormal comprehensive workability test result of concrete, as well as store and send the measurement data and test results. The series of indicators includes any combination of multiple indicators among the fluidity, viscosity, uniformity and apparent density of concrete. Equipment bracket, used for installing and arranging the concrete diversion device, the detection container, the gate group, the sensing unit and the data processing and equipment control terminal; The cloud platform communicates with the data processing and equipment control terminal to archive, analyze, and push alarms on the measurement data or detection results transmitted by the data processing and equipment control terminal, and sends the archived data and alarm information to the user terminal on a timed or event-based basis according to user needs.

2. The online monitoring system according to claim 1, characterized in that, The concrete diversion device includes a diversion and storage container, a diversion channel, a diversion and discharge port, an overflow channel, and an overflow return channel; The diversion channel connects the fresh concrete unloading channel or unloading point located near the online monitoring system to the upper part of the diversion storage container. The fresh concrete prepared by the mixing plant is transported to the fresh concrete unloading channel or unloading point via a chute or concrete mixer truck. The overflow channel is used to discharge concrete exceeding the volume limit in the drainage storage container and transport it to the aggregate equipment through the overflow return channel. The overflow return channel is also used to transport concrete that has not been tested, which is transported by the fresh concrete unloading channel or unloading point, to the aggregate equipment. The discharge port is connected between the feed channel of the discharge storage container and the detection container.

3. The online monitoring system according to claim 2, characterized in that, The volume limit is 0.8 to 1.2 times the amount of concrete required for a single test of the testing container; the inclination angle α of the overflow channel is 30° to 80°; the upper part of the discharge port is set in a gradually narrowing form, with an inclination angle γ of not less than 50°, and the minimum side length of the cross-section of the discharge port is not less than 5 times the maximum aggregate particle size of the concrete. The material storage container is also equipped with an inclined isolation screen that is connected to the overflow channel to prevent unevenly mixed concrete lumps from entering the material discharge port. The aperture of the isolation screen is 3 to 10 times the maximum aggregate size of the concrete, and the inclination angle β of the isolation screen is 20° to 50°.

4. The online monitoring system according to claim 1, characterized in that, The interior of the testing container is divided into several testing channels by several partitions. The spacing between the partitions is adjustable. The minimum side length of the cross-section of any testing channel is not less than 5 times the maximum aggregate size of the concrete, and the height is not less than 10 times the maximum aggregate size of the concrete. The outermost or middle testing channel in the testing container is selected as the feeding channel. The cross-sectional area of ​​the feeding channel is not less than 1.5 times that of the other testing channels.

5. The online monitoring system according to claim 1, characterized in that, The bottom of the testing container is provided with a testing discharge port, which consists of a gradually narrowing inclined section and a parallel extension section connected to its lower part. The inclination angle θ of the inclined section is 40° to 70°. The cross-section of the testing discharge port is circular or regular polygonal. The diameter of the parallel extension section is not less than 5 times the maximum aggregate size of the concrete. The length of the parallel extension section is not less than 3 times the maximum aggregate size of the concrete.

6. The online monitoring system according to claim 1, characterized in that, The gate assembly includes a diversion gate at the inlet of the concrete diversion device, a feed gate at the outlet of the concrete diversion device for controlling the amount of concrete loaded into the testing container, and a discharge gate at the discharge outlet of the testing container. When the testing container is in the feeding stage, the discharge gate remains closed, and the feed gate remains open. When the concrete in the testing container reaches a set amount, both the discharge gate and the feed gate remain closed, and the testing container is in a static stage. When the concrete level in each testing channel of the testing container tends to remain constant, the testing container enters the discharge stage, the discharge gate is opened, and the feed gate remains closed. The diversion gate is normally open during the testing process and is closed only when the current batch of concrete is not being tested.

7. The online monitoring system according to claim 1, characterized in that, The sensing unit includes a weight sensor and a liquid level measurement component; the weight sensor is located at the bottom of the detection container; the liquid level measurement component is a liquid level sensor group or an image recognition module, the liquid level sensor group consists of multiple liquid level sensors, each of which is located directly above a corresponding detection channel in the detection container; The image recognition module acquires images of each detection channel by adding scale lines to the transparent outer wall of each detection channel and using a camera, and then uses an image recognition algorithm to measure the height of the concrete liquid level.

8. The online monitoring system according to claim 7, characterized in that, The sensing unit also includes a temperature sensor installed on the inner or outer wall of the detection container to monitor the temperature at the concrete outlet.

9. The online monitoring system according to claim 1, characterized in that, The data processing and equipment control terminal calculates the concrete fluidity index I based on the concrete liquid level height in each detection channel of the detection container collected by the sensing unit at the start of unloading. f and apparent density ρ c0 Based on the concrete quality data collected by the sensing unit during the unloading stage of the detection container, a concrete unloading quality-time curve is obtained, and the viscosity index I of the concrete is calculated. v and uniformity index UI c .

10. The online monitoring system according to claim 9, characterized in that, The data processing and equipment control terminal calculates the concrete fluidity index I according to the following formula. f and apparent density ρ c0 : in, To measure the concrete liquid level in each detection channel at the start of unloading, k is the detection channel number, k = 1 to K, K is the number of detection channels in the container, and f() is the quantitative relationship between the flowability index and the liquid level in each detection channel established based on theoretical calculations and laboratory tests; V equ To detect the internal volume of the container, S k Let be the cross-sectional area of ​​the k-th detection channel. Let the height be the upper edge height of the k-th detection channel. This refers to the distance from the concrete liquid level in each testing channel to the upper edge of each testing channel. The data processing and equipment control terminal calculates the viscosity index I of the concrete according to the following formula. v : in, Let t1 be the average unloading rate during the uniform unloading period, and t1 and m1 be the initial time and initial unloading mass of the uniform unloading period, respectively. n and m n , respectively, represent the last time and the last unloading mass during the uniform unloading period, and g() represents the quantitative relationship between the viscosity index and the average unloading rate established based on theoretical calculations and indoor experiments; The data processing and equipment control terminal uses any one of the following three formulas to calculate the uniformity index UI of the concrete. c : Where, m i and m i+1 These represent the concrete unloading masses at the i-th and i+1-th recorded values ​​during the uniform unloading period, respectively, t. i and t i+1 These are the times for the i-th and i+1-th recorded values ​​during the uniform unloading period, respectively. This is an estimate of the concrete unloading mass at the time corresponding to the i-th recorded value. The fitting formula is obtained by linearly fitting the data of the uniform unloading period in the concrete unloading mass-time curve: Calculate the estimated value.

11. The online monitoring system according to claim 10, characterized in that, The feed channel is equipped with reinforcing bars to detect the gap passage index of the concrete. The data processing and equipment control terminal determines whether the feed channel is blocked based on the concrete level height collected by the sensing unit, and calculates the gap passage index according to the following formula: Where, δ pass This is an index for the permeability of gaps in concrete.

12. The online monitoring system according to claim 1, characterized in that, The online monitoring system also includes an alarm installed at the mixing plant; The alarm push types of the cloud platform are divided into concrete workability abnormality alarm and equipment abnormality alarm; the alarm push of the cloud platform adopts a probability risk mechanism. When an abnormality is detected and the risk probability is greater than the design threshold, an alarm reminder is sent through the user terminal and the alarm device.

13. An online monitoring method for an online monitoring system according to any one of claims 1 to 12, characterized in that, Includes the following steps: Step S1: Before the mixing plant starts producing concrete, the sensing unit is first zeroed, and the inner wall of the detection container and its connecting pipe is moistened with clean water. Step S2: When the mixing plant produces concrete, the data acquisition and equipment control terminal is turned on to initialize the opening and closing status of the gate group. Part or all of the fresh concrete delivered by the mixing plant enters the detection container, and the concrete that does not enter the detection container enters the aggregate equipment. Step S3: The sensing unit records in real time the mass m of the concrete to be tested entering the detection container and the liquid level height of the concrete in each detection channel. And transmit it to the data acquisition and equipment control terminal; Step S4: When the concrete mass m in the detection container is greater than the mass threshold m0, or the concrete liquid level in the feeding channel reaches the set height threshold, close all the gates in the gate group and let it stand for a period of time to allow the concrete liquid level in each detection channel to tend to remain constant. This is taken as the initial state before unloading, and the concrete liquid level in each detection channel at this time is recorded. and the quality of concrete inside the testing container m c0 ; Step S5: The detection container is unloaded through the gate assembly, and the mass m(t) of the concrete to be tested in the detection container and the liquid level of the concrete in each detection channel are recorded in real time by the sensing unit during the unloading process. t represents time; Step S6: After all the concrete in the detection container has been discharged, the data acquisition and equipment control terminal, based on the data recorded by the sensing unit... and m c0 Calculate the flowability index I of concrete f and apparent density ρ c0 Based on the m(t) measurement curve during the unloading process measured by the sensing unit, the viscosity index I of the concrete is calculated. v and uniformity index UI c The calculated performance indicators, along with the measurement data collected by the sensing unit, are uploaded to the cloud platform as test results. Step S7: The cloud platform archives, analyzes, and pushes alarms on the data uploaded by the data acquisition and device control terminal, and the results are pushed to the user terminal in real time. Step S8: If the on-site pouring is not yet completed, return to step S2 and continue with the next concrete test; if the on-site pouring is completed, clean the test container and wait for the next start-up test.

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