A down-pressure fresh concrete aggregate homogeneity detection system and detection method

Abstract

The present invention provides a downward pressure fresh concrete aggregate homogeneity detection system. When in use, fresh concrete is poured into the upper barrel, and then a gravity hammer is placed to accelerate the fresh concrete to flow downward, pass through the steel bar simulation mesh and enter the lower barrel until the lower barrel is fully loaded; concrete in the upper and lower barrels is taken respectively, and recorded as the first and second samples respectively; the first and second samples of the same mass are sieved using an intelligent sieve, and the mass of the material on the second sieve is weighed to obtain the coarse aggregate mass H1 and H2 in the first and second samples respectively; the aggregate homogeneity S = H2 / H1×100% is calculated. A related detection method is also provided. The system and method of the present invention can simulate the flow state of fresh concrete before and after passing through the steel bar barrier, and screen and measure the coarse aggregate of concrete before and after the flow, thereby detecting the aggregate homogeneity of fresh concrete after passing through the steel bar barrier.

Description

Technical Field

[0001] The present invention relates to the field of aggregate homogeneity detection technology, more specifically, to the field of fresh concrete aggregate homogeneity detection technology, and in particular to a down-pressure fresh concrete aggregate homogeneity detection system and detection method. Background Art

[0002] Concrete is a building material composed of cement, aggregate and water. Its homogeneity directly affects the service performance and service life of concrete.

[0003] When mix design is poor, mixing is insufficient, pumping pressure is excessive, mixing mechanisms are inadequate during transportation, and waiting times are excessive, the components of fresh concrete become unevenly distributed spatially, posing a significant threat to concrete structures. Furthermore, concrete homogeneity can easily change between mixing and mold placement. For example, it's common for concrete to be homogeneous upon unloading from a truck mixer but segregate after pumping or long-distance flow. This unevenness can lead to localized strength deficiencies in hardened concrete components. Core sampling reveals that these areas of concrete lacking strength are often composed almost entirely of mortar, lacking coarse aggregate. Furthermore, due to the restraining effect of coarse aggregate, concrete shrinkage during hardening is much smaller than that of mortar. Consequently, concrete with poor homogeneity significantly increases the risk of localized shrinkage cracking. For these reasons, there is an urgent need to establish a fresh concrete homogeneity evaluation method to guide commercial concrete ready-mix plants, improve the homogeneity of fresh concrete, and ensure the structural performance of hardened concrete.

[0004] The existing standard JGJ / T 283-2012, "Technical Specification for the Application of Self-Compacting Concrete," uses a vibration method to test the segregation rate for aggregate uniformity in high-flow self-compacting concrete. This method begins by loading the self-compacting concrete mixture into a stability test cylinder using a hopper, leveling it to the hopper opening. The hopper is then removed vertically and allowed to rest for 1 minute. Excess mixture is then removed and smoothed with a spatula. The stability test cylinder is placed on a jumping table, and the crank is rotated once per second, causing the table to vibrate 25 times. The stability test cylinder is removed in sections, and the mixture in each section is placed through a 5mm round-hole sieve. The mixture is rinsed with clean water to remove the slurry and fine aggregate. The remaining coarse aggregate is wiped dry with a sponge and weighed to the nearest 1g using a balance. The wet weights of the coarse aggregate in the upper, middle, and lower sections are calculated as m1, m2, and m3, respectively.

[0005] The above test method has the following disadvantages:

[0006] 1. The instrument is bulky. Because this method generates vibration by jumping on a table, the test must be performed indoors, occupying indoor space and increasing construction site costs.

[0007] 2. Dependence on power supply: This method often uses power supply to put the jumping table into working state, which consumes energy and increases carbon emissions and carbon tax costs on the construction site.

[0008] 3. Simulation distortion. In this method, concrete moves only under vibration conditions, which cannot simulate the flow state of concrete through the rigid collision of dense steel mesh during actual pouring. This method also makes it difficult to characterize the barrier effect of steel bars on the flowing concrete aggregate. Therefore, the measured aggregate distribution is different from that during actual pouring.

[0009] Therefore, it is hoped to provide a fresh concrete aggregate homogeneity detection system and detection method, which can simulate the flow state of fresh concrete before and after passing through steel bar barrier, and screen and measure the coarse aggregate of concrete before and after flowing, so as to detect the aggregate homogeneity of fresh concrete after passing through steel bar barrier. Summary of the Invention

[0010] In order to overcome the shortcomings of the above-mentioned prior art, one object of the present invention is to provide a downward pressure fresh concrete aggregate homogeneity detection system, which can simulate the flow state of fresh concrete before and after passing through steel bar barrier, and screen and measure the coarse aggregate of concrete before and after flowing, so as to detect the aggregate homogeneity of fresh concrete after passing through steel bar barrier, and is suitable for large-scale promotion and application.

[0011] Another object of the present invention is to provide a downward pressure method for detecting the homogeneity of fresh concrete aggregates, which simulates the flow state of fresh concrete before and after passing through steel bars and screens and measures the coarse aggregates of concrete before and after flowing, thereby detecting the homogeneity of the aggregates after the fresh concrete passes through the steel bars. The method is suitable for large-scale promotion and application.

[0012] To achieve the above objectives, in a first aspect of the present invention, a down-pressure fresh concrete aggregate homogeneity detection system is provided, which is characterized by comprising a flow device and a screening and washing device, wherein:

[0013] The flow device includes an upper barrel body, a lower barrel body, a steel simulation net and a gravity pressure hammer, the upper barrel body and the lower barrel body are both arranged vertically, the top and bottom of the upper barrel body and the top of the lower barrel body are all open, the bottom of the upper barrel body is detachably arranged on the top of the lower barrel body, and the bottom of the lower barrel body is vertically provided with air holes, the steel simulation net is arranged horizontally and includes an annular ring and a plurality of straight rods, the annular ring is arranged horizontally and detachably arranged in the top of the lower barrel body, the straight rods are arranged along the front and rear directions and are located in the annular ring, the front and rear ends of the straight rods are respectively connected to the annular ring, the plurality of straight rods are arranged at intervals from each other on the left and right, the gravity pressure hammer is arranged vertically, the outer contour of the cross section of the gravity pressure hammer matches the outer contour of the cross section of the upper barrel body, and the gravity pressure hammer is used to be vertically movably inserted in the upper barrel body;

[0014] The screening and washing device includes an intelligent screen set, and the intelligent screen set includes a first screen and a second screen, the first screen includes a first sleeve, a first screen and a first photoelectric sensor, the first sleeve is vertically arranged, the first screen is horizontally arranged in the first sleeve, the first photoelectric sensor includes a first transmitting end and a first receiving end, the first transmitting end and the first receiving end are relatively spaced apart from each other, the first transmitting end and the first receiving end are both located in the first sleeve and are connected to the first sleeve and are both located under the first screen for detecting dropped objects falling through the first screen, the second screen includes a second sleeve, A second screen and a second photoelectric sensor, the second sleeve is vertically arranged, the second screen is horizontally arranged in the second sleeve, the second photoelectric sensor includes a second transmitting end and a second receiving end, the second transmitting end and the second receiving end are relatively spaced apart on the left and right, the second transmitting end and the second receiving end are both located in the second sleeve and are both connected to the second sleeve and are both located under the second screen for detecting dropped objects falling through the second screen, the upper end of the second sleeve is vertically sleeved outside the lower end of the first sleeve, the aperture of the first screen is 9.5mm, and the aperture of the second screen is 4.75mm.

[0015] Preferably, the diameter of the upper barrel body and the diameter of the lower barrel body are both 100 mm, the height of the upper barrel body is 180 mm, and the barrel depth of the lower barrel body is 80 mm.

[0016] Preferably, the number of the straight rods is 2 or 3.

[0017] Preferably, the air hole is arranged at the center of the bottom of the lower barrel.

[0018] Preferably, the first sleeve and the second sleeve are both square sleeves, and the square sleeves are both arranged in the left-right direction.

[0019] Preferably, the first sleeve includes a first upper sleeve and a first lower sleeve, the first upper sleeve and the first lower sleeve are both arranged vertically, the upper end of the first lower sleeve is vertically sleeved outside the lower end of the first upper sleeve, the first screen is horizontally arranged in the first upper sleeve, the first transmitting end and the first receiving end are both located in the first lower sleeve and are both connected to the first lower sleeve, the second sleeve includes a second upper sleeve and a second lower sleeve, the second upper sleeve and the second lower sleeve are both arranged vertically, the upper end of the second lower sleeve is vertically sleeved outside the lower end of the second upper sleeve, the second screen is horizontally arranged in the second upper sleeve, the second transmitting end and the second receiving end are both located in the second lower sleeve and are both connected to the second lower sleeve, and the upper end of the second upper sleeve is vertically sleeved outside the lower end of the first lower sleeve.

[0020] In a second aspect of the present invention, a method for detecting the homogeneity of fresh concrete aggregates by downward pressure is provided. The method is characterized in that the method is performed using the aforementioned downward pressure fresh concrete aggregate homogeneity detection system and comprises the following steps:

[0021] (1) pouring fresh concrete into the upper barrel from the top of the upper barrel, placing the gravity hammer into the upper barrel from the top of the upper barrel and pressing it on the fresh concrete, so that the fresh concrete is accelerated to flow downward, pass through the steel bar simulation mesh and enter the lower barrel until the lower barrel is fully loaded;

[0022] (2) removing the gravity hammer, the upper barrel, and the steel bar simulation mesh, taking the concrete in the upper barrel as the first sample, and taking the concrete in the lower barrel as the second sample;

[0023] (3) Weighing the first sample and the second sample of the same mass respectively, and screening them respectively using the intelligent sieve set, wherein the screening process is as follows: placing the first sample or the second sample from the upper end of the first sleeve into the first sleeve and placing it on the first sieve, screening under a flowing water source, and shaking the sieve until the first photoelectric sensor and the second photoelectric sensor detect no dropped objects within a preset time, and the screening is completed;

[0024] (4) Weighing the mass of the material on the second sieve when screening the first sample and the mass of the material on the second sieve when screening the second sample, respectively, to obtain the mass H1 of the coarse aggregate in the first sample and the mass H2 of the coarse aggregate in the second sample;

[0025] (5) Calculate the aggregate homogeneity S = H2 / H1×100% after the fresh concrete passes through the steel bar simulation mesh.

[0026] Preferably, in step (3), the preset time is 60 seconds.

[0027] Preferably, in step (3), the mass of the first sample and the mass of the second sample are both 1000 g.

[0028] Preferably, in step (4), the weighing accuracy is up to 0.5 g.

[0029] The beneficial effects of the present invention are:

[0030] 1. When the downward pressure type fresh concrete aggregate homogeneity detection system of the present invention is used, fresh concrete is poured into the upper barrel from the top of the upper barrel, and a gravity pressure hammer is placed into the upper barrel from the top of the upper barrel and pressed on the fresh concrete to accelerate the fresh concrete to flow downward, pass through the steel bar simulation net and enter the lower barrel until the lower barrel is fully loaded; the gravity pressure hammer, the upper barrel and the steel bar simulation net are removed, and the concrete in the upper barrel is taken out and recorded as the first sample, and the concrete in the barrel is taken out and recorded as the second sample; the first sample and the second sample of the same mass are respectively weighed and sieved using the intelligent set sieve. The sieving process is as follows: the first sample or the second sample is taken out and recorded as the first sample or the second sample. The sample is placed into the first sleeve from the upper end of the first sleeve and placed on the first sieve, and is screened under a flowing water source. The sieve is shaken until the first photoelectric sensor and the second photoelectric sensor detect no dropped objects within a preset time, and the screening is completed; the mass of the material on the second sieve is weighed to obtain the mass H1 and H2 of the coarse aggregate in the first sample and the second sample respectively; the aggregate homogeneity S=H2 / H1×100% is calculated. Therefore, it can simulate the flow state of fresh concrete before and after passing through the steel bar barrier, and screen and measure the coarse aggregate of concrete before and after flowing, so as to detect the aggregate homogeneity of fresh concrete after passing through the steel bar barrier, and is suitable for large-scale promotion and application.

[0031] 2. The downward pressure type fresh concrete aggregate homogeneity detection method of the present invention comprises: pouring fresh concrete into the upper barrel from the top of the upper barrel, placing a gravity hammer into the upper barrel from the top of the upper barrel and pressing on the fresh concrete, so that the fresh concrete is accelerated to flow downward, pass through the steel bar simulation net and enter the lower barrel until the lower barrel is fully loaded; removing the gravity hammer, the upper barrel and the steel bar simulation net, taking the concrete in the upper barrel as the first sample, and taking the concrete in the barrel as the second sample; weighing the first sample and the second sample of the same mass respectively, and screening them respectively using the intelligent set sieve, and the screening process is as follows: the first sample or the second sample is taken out. The method is to place the material from the upper end of the first sleeve into the first sleeve and place it on the first sieve, screen under a flowing water source, and shake the sieve until the first photoelectric sensor and the second photoelectric sensor detect no dropped objects within a preset time, and the screening is completed; weigh the mass of the material on the second sieve to obtain the mass H1 and H2 of the coarse aggregate in the first sample and the second sample respectively; calculate the aggregate homogeneity S=H2 / H1×100%. Therefore, it simulates the flow state of fresh concrete before and after passing through the steel bar barrier and screens and measures the coarse aggregate of the concrete before and after the flow, thereby detecting the aggregate homogeneity of the fresh concrete after passing through the steel bar barrier, and is suitable for large-scale promotion and application.

[0032] These and other objects, features and advantages of the present invention will be more fully reflected in the following detailed description and claims, and may be achieved by means of the means, devices and combinations particularly pointed out in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The figure is a perspective exploded schematic diagram of a flow device of a specific embodiment of the downward pressure type fresh concrete aggregate homogeneity detection system of the present invention.

[0034] Figure 2 yes Figure 1 The schematic diagram of the front cross-section of the intelligent screen set of the screening and washing device of the specific embodiment shown is shown.

[0035] Figure 3 The present invention is a schematic diagram of a logic flow of determining the completion of screening in a specific embodiment of the downward pressure type fresh concrete aggregate homogeneity detection method of the present invention.

[0036] (Explanation of Symbols)

[0037] 1. Upper barrel; 2. Lower barrel; 3. Steel bar simulation mesh; 4. Gravity pressure hammer; 5. Air hole; 6. Annular ring; 7. Straight rod; 8. First sieve; 9. Second sieve; 10. First sleeve; 11. First screen; 12. First photoelectric sensor; 13. First transmitting end; 14. First receiving end; 15. Second sleeve; 16. Second screen; 17. Second photoelectric sensor; 18. Second transmitting end; 19. Second receiving end; 20. First upper sleeve; 21. First lower sleeve; 22. Second upper sleeve; 23. Second lower sleeve; 24. Light. DETAILED DESCRIPTION

[0038] Explanation of relevant terms:

[0039] Fresh concrete: also known as concrete mixture, is a mixture obtained by mixing cement, water, mineral admixtures, additives and coarse and fine aggregates. It is cement concrete that has not yet solidified and is used in the construction process.

[0040] High-fluidity concrete: also known as "pumping concrete", concrete with a mixture slump of not less than 160mm.

[0041] Segregation: Segregation occurs when coarse aggregate in concrete sinks due to gravity within the mortar, resulting in uneven spatial distribution. Causes of coarse aggregate segregation include differences in density between the coarse aggregate and mortar, differences in flow properties between the two, and differences in coarse and fine aggregate particle sizes. These factors can have an impact individually or in combination.

[0042] In order to simulate the flow state of concrete passing through the rigid collision of dense steel mesh during actual pouring, characterize the barrier effect of steel bars on the flowing concrete aggregate, and make the measured aggregate distribution as similar as possible to that during actual pouring, the inventors have invented a downward pressure fresh concrete aggregate homogeneity detection system through in-depth and extensive research. This downward pressure fresh concrete aggregate homogeneity detection system can simulate the flow state of fresh concrete before and after passing through steel bar obstruction, and screen and measure the coarse aggregate of concrete before and after flowing, thereby detecting the aggregate homogeneity of fresh concrete after passing through steel bar obstruction.

[0043] See Figures 1 and 2 As shown, in a specific embodiment of the present invention, the down-pressure fresh concrete aggregate homogeneity detection system of the present invention includes a flow device and a screening and washing device, wherein:

[0044] The flow device includes an upper barrel body 1, a lower barrel body 2, a steel bar simulation net 3 and a gravity pressure hammer 4, the upper barrel body 1 and the lower barrel body 2 are both arranged vertically, the top and bottom of the upper barrel body 1 and the top of the lower barrel body 2 are all open, the bottom of the upper barrel body 1 is detachably arranged on the top of the lower barrel body 2, and the bottom of the lower barrel body 2 is vertically provided with an air hole 5, the steel bar simulation net 3 is arranged horizontally and includes an annular ring 6 and a plurality of straight rods 7, the annular ring 6 is arranged horizontally and detachably arranged in the top of the lower barrel body 2, the straight rod 7 is arranged along the front and rear directions and is located in the annular ring 6, the front and rear ends of the straight rod 7 are respectively connected to the annular ring 6, the plurality of straight rods 7 are arranged at intervals from each other on the left and right, the gravity pressure hammer 4 is arranged vertically, the outer contour of the cross section of the gravity pressure hammer 4 matches the outer contour of the cross section of the upper barrel body 1, and the gravity pressure hammer 4 is used to be vertically movably inserted in the upper barrel body 1;

[0045] The screening and washing device includes an intelligent screen set, and the intelligent screen set includes a first screen 8 and a second screen 9. The first screen 8 includes a first sleeve 10, a first screen 11 and a first photoelectric sensor 12. The first sleeve 10 is vertically arranged, and the first screen 11 is horizontally arranged in the first sleeve 10. The first photoelectric sensor 12 includes a first transmitting end 13 and a first receiving end 14. The first transmitting end 13 and the first receiving end 14 are relatively spaced apart. The first transmitting end 13 and the first receiving end 14 are both located in the first sleeve 10 and are both connected to the first sleeve 10 and are both located under the first screen 11 for detecting dropped objects falling through the first screen 11. The second screen 9 includes a second sleeve 15, The second screen 16 and the second photoelectric sensor 17 are arranged vertically in the second sleeve 15, and the second screen 16 is arranged horizontally in the second sleeve 15. The second photoelectric sensor 17 includes a second transmitting end 18 and a second receiving end 19. The second transmitting end 18 and the second receiving end 19 are spaced apart from each other. The second transmitting end 18 and the second receiving end 19 are both located in the second sleeve 15 and connected to the second sleeve 15. Both are located below the second screen 16 to detect dropped objects that fall through the second screen 16. The upper end of the second sleeve 15 is vertically sleeved outside the lower end of the first sleeve 10. The aperture of the first screen 11 is 9.5mm, and the aperture of the second screen 16 is 4.75mm. In other words, aggregate larger than 4.75mm and smaller than 9.5mm can be determined as coarse aggregate.

[0046] With the above arrangement, the flow device is used to evaluate the ability of concrete to maintain uniformity after passing through a narrow opening (including the space between steel bars and other obstacles); the coarse aggregate of the concrete in the upper barrel 1 (in its original state) and the concrete in the lower barrel 2 (after passing through the gaps between the straight rods 7 of the steel simulation mesh 3) is screened by the screening and washing device, and the stone content of the concrete is calculated after weighing, and the ratio of the stone content is calculated. This ratio is defined as an indicator of the degree to which the aggregate homogeneity of the concrete is maintained after passing through the blockage.

[0047] The diameter of the upper barrel body 1, the diameter of the lower barrel body 2, the height of the upper barrel body 1 and the barrel depth of the lower barrel body 2 can be determined as needed. Figure 1 As shown, in a specific embodiment of the present invention, the diameter of the upper barrel body 1 and the diameter of the lower barrel body 2 are both 100 mm, the height of the upper barrel body 1 is 180 mm, and the depth of the lower barrel body 2 is 80 mm.

[0048] The straight rods 7 are used to simulate steel bars. The more straight rods 7 there are, the denser the steel bars are simulated. The number of straight rods 7 can be determined as needed. Preferably, the number of straight rods 7 is 2 or 3. Figure 1 As shown, in a specific embodiment of the present invention, the number of the straight rods 7 is 3.

[0049] The bottom of the lower barrel 2 is vertically provided with an air hole 5, which can be provided at any suitable position on the bottom of the lower barrel 2. Figure 1 As shown, in a specific embodiment of the present invention, the air hole 5 is arranged at the central position of the bottom of the lower barrel body 2.

[0050] The first sleeve 10 and the second sleeve 15 may have any suitable shape. In a specific embodiment of the present invention, the first sleeve 10 and the second sleeve 15 are both square sleeves, and the square sleeves are both arranged in the left-right direction. That is, the cross-section of the first sleeve 10 and the cross-section of the second sleeve 15 are both square.

[0051] The length of the square sleeve, i.e. the dimension along the left and right directions, can be determined as needed. Figure 2 As shown, in a specific embodiment of the present invention, the length of the square sleeve is 220 mm.

[0052] The first sleeve 10 and the second sleeve 15 may have any suitable configuration. Figure 2As shown, in a specific embodiment of the present invention, the first sleeve 10 includes a first upper sleeve 20 and a first lower sleeve 21, the first upper sleeve 20 and the first lower sleeve 21 are both vertically arranged, the upper end of the first lower sleeve 21 is vertically sleeved outside the lower end of the first upper sleeve 20, the first screen 11 is horizontally arranged in the first upper sleeve 20, the first transmitting end 13 and the first receiving end 14 are both located in the first lower sleeve 21 and are connected to the first lower sleeve 21, and the second sleeve 15 It includes a second upper sleeve 22 and a second lower sleeve 23, the second upper sleeve 22 and the second lower sleeve 23 are both arranged vertically, the upper end of the second lower sleeve 23 is vertically sleeved outside the lower end of the second upper sleeve 22, the second screen 16 is horizontally arranged in the second upper sleeve 22, the second transmitting end 18 and the second receiving end 19 are both located in the second lower sleeve 23 and are both connected to the second lower sleeve 23, and the upper end of the second upper sleeve 22 is vertically sleeved outside the lower end of the first lower sleeve 21.

[0053] The height of the first upper sleeve 20, the height of the second upper sleeve 22, the height of the first lower sleeve 21 and the height of the second lower sleeve 23 can be determined as needed. Figure 2 As shown, in a specific embodiment of the present invention, the height of the first upper sleeve 20 and the height of the second upper sleeve 22 are both 70 mm, and the height of the first lower sleeve 21 and the height of the second lower sleeve 23 are both 40 mm.

[0054] The present invention also provides a method for detecting the homogeneity of fresh concrete aggregates by downward pressure, which is performed using the aforementioned system for detecting the homogeneity of fresh concrete aggregates by downward pressure and comprises the following steps:

[0055] (1) pouring fresh concrete into the upper barrel 1 from the top of the upper barrel 1, placing the gravity hammer 4 into the upper barrel 1 from the top of the upper barrel 1 and pressing it on the fresh concrete, so that the fresh concrete is accelerated to flow downward, pass through the steel bar simulation mesh 3 and enter the lower barrel 2 until the lower barrel 2 is fully loaded;

[0056] (2) Remove the gravity hammer 4, the upper barrel 1 and the steel bar simulation mesh 3, take the concrete in the upper barrel 1 as the first sample, and take the concrete in the lower barrel 2 as the second sample;

[0057] (3) Weighing the first sample and the second sample of the same mass respectively, and sieving them respectively using the intelligent sieve set, wherein the sieving process is as follows: placing the first sample or the second sample from the upper end of the first sleeve 10 into the first sleeve 10 and placing it on the first sieve 11, sieving under a flowing water source, and shaking the sieve until the first photoelectric sensor 12 and the second photoelectric sensor 17 detect no dropped objects within a preset time, and the sieving is completed;

[0058] (4) Weighing the mass of the material on the second sieve 16 when screening the first sample and the mass of the material on the second sieve 16 when screening the second sample, respectively, to obtain the mass H1 of the coarse aggregate in the first sample and the mass H2 of the coarse aggregate in the second sample;

[0059] (5) Calculate the aggregate uniformity S of the fresh concrete after it passes through the steel simulated mesh: S = H2 / H1 × 100%. S is a value less than or equal to 1. If S is 100%, it means that the aggregate uniformity of the concrete remains completely consistent after flowing; the lower the value of S, the worse the aggregate uniformity of the concrete after flowing.

[0060] In the step (3), the preset time can be determined as needed. Preferably, in the step (3), the preset time is 60 seconds.

[0061] In the step (3), the mass of the first sample and the mass of the second sample can be determined as needed. Preferably, in the step (3), the mass of the first sample and the mass of the second sample are both 1000 g.

[0062] In the step (4), the precision of the weighing can be determined as needed. Preferably, in the step (4), the precision of the weighing is up to 0.5 g.

[0063] In order to more clearly understand the technical content of the present invention, the following measurement examples are given to illustrate in detail. Figures 1 and 2 The downward pressure fresh concrete aggregate homogeneity detection system shown is used.

[0064] In the following examples, the experimental methods without specific conditions are generally measured according to national standards. If there are no corresponding national standards, they are carried out according to the general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0065] Unless otherwise defined or indicated, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein can be applied to the methods of the present invention.

[0066] Measurement Example 1

[0067] Fresh concrete: C30 cement: water: sand: stone: water reducer = 400: 176: 748: 1076 (containing 31.17% coarse aggregate)

[0068] Step 1: Flow simulation

[0069] 1) Select steel bar simulation mesh 3 of different densities as needed to set up the obstruction. Here, a steel bar simulation mesh 3 with three straight rods 7 is selected. After the upper barrel 1 of the mobile device is detachably mounted on the lower barrel 2, fresh concrete is poured into the upper barrel 1 from the top.

[0070] 2) Place the gravity hammer 4 into the upper barrel 1 from the top and press it on the fresh concrete, so that the concrete is accelerated by pressure and flows through the steel simulation mesh 3 and into the lower barrel 2. When the lower barrel 2 is fully loaded, the flow simulation is completed.

[0071] Step 2: Separation and sampling

[0072] 3) Remove the gravity hammer 4, the upper barrel 1 and the steel simulation mesh 3, and take the concrete in the upper barrel 1, which is recorded as the first sample.

[0073] 4) Take out the concrete in barrel 2 and record it as the second sample.

[0074] Step 3: Post-processing and calculation of stone content ratio

[0075] 5) Take 1000g of the first sample and the second sample respectively, and screen them using the intelligent sieve of the screening and washing device. The screening process is as follows: put the first sample or the second sample into the first sleeve 10 from the upper end and place it on the first sieve 11, screen it under flowing water, and shake the sieve until the first photoelectric sensor 12 and the second photoelectric sensor 17 detect no dropped objects within the preset time of 60 seconds, and the screening is completed.

[0076] The above-mentioned “shaking screen” can be achieved by, for example, fixing (for example, snapping or clamping) the entire intelligent screen set on a vibrator and vibrating the vibrator.

[0077] The transmitting end of the photoelectric sensor emits light 24 to the receiving end. The space through which light 24 passes is the detection space. If something falls from the screen, it will block light 24 when passing through the detection space, and the receiving end will not receive light 24. The photoelectric pulse circuit of the photoelectric sensor will generate an electrical pulse signal. Each time the light is blocked, an electrical pulse signal is generated. If no electrical pulse signal is generated, it means that no object has fallen from the screen.

[0078] The photoelectric sensor can be connected to another control device by signal, and the control device can also be connected to the above-mentioned vibrator by signal. The photoelectric sensor sends an electric pulse signal to the control device. If no electric pulse signal is received within the preset time of 60 seconds, the control device determines that the screening is completed, sends a stop signal to the vibrator, and controls the vibrator to stop vibrating.

[0079] The logic flow diagram for determining the completion of screening can be as follows: Figure 3 As shown, the detection logic is: when the screen is shaken, a 60-second countdown starts. Every time a photoelectric sensor determines that there is a falling object, the 60-second countdown starts again; when no falling object is found within 60 consecutive seconds, it can be determined that the screening is completed and the screening is stopped.

[0080] 6) Weigh the mass of the material on the second sieve 16 when screening the first sample and the mass of the material on the second sieve 16 when screening the second sample, respectively, to the nearest 0.5 g, and obtain the mass of the coarse aggregate in the first sample H1 = 318 g and the mass of the coarse aggregate in the second sample H2 = 303.5 g, respectively.

[0081] 7) Calculate the aggregate homogeneity S after the fresh concrete passes through the steel simulation mesh 3 = H2 / H1×100% = 95.44%.

[0082] Therefore, the aggregate uniformity of the concrete is in the range of 95%-100%. Under the set working conditions, the coarse aggregate has high uniformity and the rebound strength data is stable. When the strength of the specimen reaches the standard, the qualified rate of the rebound data can be guaranteed.

[0083] Measurement Example 2

[0084] Fresh concrete: C40 cement: water: sand: stone: water reducer = 440:172:734:1054 (containing 30.58% coarse aggregate)

[0085] Step 1: Flow simulation

[0086] 1) Select steel bar simulation mesh 3 of different densities as needed to set up the obstruction. Here, a steel bar simulation mesh 3 with three straight rods 7 is selected. After the upper barrel 1 of the mobile device is detachably mounted on the lower barrel 2, fresh concrete is poured into the upper barrel 1 from the top.

[0087] 2) Place the gravity hammer 4 into the upper barrel 1 from the top and press it on the fresh concrete, so that the concrete is accelerated by pressure and flows through the steel simulation mesh 3 and into the lower barrel 2. When the lower barrel 2 is fully loaded, the flow simulation is completed.

[0088] Step 2: Separation and sampling

[0089] 3) Remove the gravity hammer 4, the upper barrel 1 and the steel simulation mesh 3, and take the concrete in the upper barrel 1, which is recorded as the first sample.

[0090] 4) Take out the concrete in barrel 2 and record it as the second sample.

[0091] Step 3: Post-processing and calculation of stone content ratio

[0092] 5) Take 1000g of the first sample and the second sample respectively, and screen them using the intelligent sieve of the screening and washing device. The screening process is as follows: put the first sample or the second sample into the first sleeve 10 from the upper end and place it on the first sieve 11, screen it under flowing water, and shake the sieve until the first photoelectric sensor 12 and the second photoelectric sensor 17 detect no dropped objects within the preset time of 60 seconds, and the screening is completed.

[0093] The above-mentioned “shaking screen” can be achieved by, for example, fixing (for example, snapping or clamping) the entire intelligent screen set on a vibrator and vibrating the vibrator.

[0094] The transmitting end of the photoelectric sensor emits light 24 to the receiving end. The space through which light 24 passes is the detection space. If something falls from the screen, it will block light 24 when passing through the detection space, and the receiving end will not receive light 24. The photoelectric pulse circuit of the photoelectric sensor will generate an electrical pulse signal. Each time the light is blocked, an electrical pulse signal is generated. If no electrical pulse signal is generated, it means that no object has fallen from the screen.

[0095] The photoelectric sensor can be connected to another control device by signal, and the control device can also be connected to the above-mentioned vibrator by signal. The photoelectric sensor sends an electric pulse signal to the control device. If no electric pulse signal is received within the preset time of 60 seconds, the control device determines that the screening is completed, sends a stop signal to the vibrator, and controls the vibrator to stop vibrating.

[0096] The logical flow diagram for determining the completion of screening is as follows: Figure 3 As shown, the detection logic is: when the screen is shaken, a 60-second countdown starts. Every time a photoelectric sensor determines that there is a falling object, the 60-second countdown starts again; when no falling object is found within 60 consecutive seconds, it can be determined that the screening is completed and the screening is stopped.

[0097] 6) Weigh the mass of the material on the second sieve 16 when screening the first sample and the mass of the material on the second sieve 16 when screening the second sample, respectively, to the nearest 0.5 g, and obtain the mass of the coarse aggregate in the first sample H1 = 306.5 g and the mass of the coarse aggregate in the second sample H2 = 291 g, respectively.

[0098] 7) Calculate the aggregate homogeneity S after the fresh concrete passes through the steel simulation mesh 3 = H2 / H1×100% = 94.9%.

[0099] Therefore, the aggregate uniformity of the concrete is in the range of 90%-95%. Under the set working conditions, the coarse aggregate has a high uniformity and the rebound strength data is relatively stable. When the strength of the specimen reaches the standard, the qualified rate of the rebound data can be guaranteed to a certain extent.

[0100] Measurement Example 3

[0101] Fresh concrete: C60 self-compacting concrete cement: fly ash: mineral powder: silica fume: sand: crushed stone: water: admixture = 274:110:137:27:836:888:148:8.8 (containing 36.56% coarse aggregate)

[0102] Step 1: Flow simulation

[0103] 1) Select steel bar simulation mesh 3 of different densities as needed to set up the obstruction. Here, a steel bar simulation mesh 3 with three straight rods 7 is selected. After the upper barrel 1 of the mobile device is detachably mounted on the lower barrel 2, fresh concrete is poured into the upper barrel 1 from the top.

[0104] 2) Place the gravity hammer 4 into the upper barrel 1 from the top and press it on the fresh concrete, so that the concrete is accelerated by pressure and flows through the steel simulation mesh 3 and into the lower barrel 2. When the lower barrel 2 is fully loaded, the flow simulation is completed.

[0105] Step 2: Separation and sampling

[0106] 3) Remove the gravity hammer 4, the upper barrel 1 and the steel simulation mesh 3, and take the concrete in the upper barrel 1, which is recorded as the first sample.

[0107] 4) Take out the concrete in barrel 2 and record it as the second sample.

[0108] Step 3: Post-processing and calculation of stone content ratio

[0109] 5) Take 1000g of the first sample and the second sample respectively, and screen them using the intelligent sieve of the screening and washing device. The screening process is as follows: put the first sample or the second sample into the first sleeve 10 from the upper end and place it on the first sieve 11, screen it under flowing water, and shake the sieve until the first photoelectric sensor 12 and the second photoelectric sensor 17 detect no dropped objects within the preset time of 60 seconds, and the screening is completed.

[0110] The above-mentioned “shaking screen” can be achieved by, for example, fixing (for example, snapping or clamping) the entire intelligent screen set on a vibrator and vibrating the vibrator.

[0111] The transmitting end of the photoelectric sensor emits light 24 to the receiving end. The space through which light 24 passes is the detection space. If something falls from the screen, it will block light 24 when passing through the detection space, and the receiving end will not receive light 24. The photoelectric pulse circuit of the photoelectric sensor will generate an electrical pulse signal. Each time the light is blocked, an electrical pulse signal is generated. If no electrical pulse signal is generated, it means that no object has fallen from the screen.

[0112] The photoelectric sensor can be connected to another control device by signal, and the control device can also be connected to the above-mentioned vibrator by signal. The photoelectric sensor sends an electric pulse signal to the control device. If no electric pulse signal is received within the preset time of 60 seconds, the control device determines that the screening is completed, sends a stop signal to the vibrator, and controls the vibrator to stop vibrating.

[0113] The logical flow diagram for determining the completion of screening is as follows: Figure 3 As shown, the detection logic is: when the screen is shaken, a 60-second countdown starts. Every time a photoelectric sensor determines that there is a falling object, the 60-second countdown starts again; when no falling object is found within 60 consecutive seconds, it can be determined that the screening is completed and the screening is stopped.

[0114] 6) Weigh the mass of the material on the second sieve 16 when screening the first sample and the mass of the material on the second sieve 16 when screening the second sample, respectively, to the nearest 0.5 g, and obtain the mass of the coarse aggregate in the first sample H1 = 379.5 g and the mass of the coarse aggregate in the second sample H2 = 333 g, respectively.

[0115] 7) Calculate the aggregate homogeneity of the fresh concrete after it passes through the steel simulation mesh 3: S = H2 / H1×100% = 87.7%.

[0116] Therefore, the aggregate uniformity of the concrete is less than 90%, the homogeneity of the coarse aggregate is poor under the set working conditions, and the rebound strength data fluctuates greatly. When the strength of the specimen meets the standard, the local strength may still fail to meet the design standard due to uneven distribution of aggregate.

[0117] To address the poor uniformity of coarse aggregate in existing high-flow concrete, the present invention has designed a system and method for rapidly testing concrete aggregate uniformity on-site. This system and method simulates the flow of high-flow concrete under varying steel density conditions. It intercepts concrete before and after flow and intelligently screens it using a photoelectric sensor. Through weighing and calculation, the uniformity of the concrete aggregate is ultimately evaluated as it flows to areas with dense steel.

[0118] Compared with the prior art, the present invention has the following advantages:

[0119] 1. Realistic simulation: The present invention can realistically simulate the component state of concrete after flowing through steel bars in actual construction, thereby improving the authenticity and credibility of aggregate distribution.

[0120] 2. The instrument is simple and easy to operate: the uniformity of aggregate is tested by natural flow, and the instrument can be operated on any flat ground without the need for indoor power supply; the photoelectric sensor is used to determine whether the screening is completed, and it can be operated by one person, so the learning cost for the operator is low.

[0121] 3. Fast and efficient: The flow is accelerated by the gravity hammer, and the screening completion is reliably determined by the photoelectric sensor. After the concrete mixture arrives at the test site, the uniformity test results can be obtained within 10 minutes.

[0122] In summary, the downward pressure fresh concrete aggregate homogeneity detection system and method of the present invention can simulate the flow state of fresh concrete before and after passing through the steel bar barrier, and screen and measure the coarse aggregate of concrete before and after flowing, thereby detecting the aggregate homogeneity of fresh concrete after passing through the steel bar barrier, and is suitable for large-scale promotion and application.

[0123] In this specification, the present invention has been described with reference to specific embodiments thereof. However, it will be apparent that various modifications and variations may be made without departing from the spirit and scope of the present invention. Therefore, the description is to be regarded as illustrative rather than restrictive.

Claims

1. A down-pressure fresh concrete aggregate homogeneity detection system, characterized in that: It includes a flow device and a screening and washing device, wherein: The flow device includes an upper barrel body, a lower barrel body, a steel simulation net and a gravity pressure hammer, the upper barrel body and the lower barrel body are both arranged vertically, the top and bottom of the upper barrel body and the top of the lower barrel body are all open, the bottom of the upper barrel body is detachably arranged on the top of the lower barrel body, and the bottom of the lower barrel body is vertically provided with air holes, the steel simulation net is arranged horizontally and includes an annular ring and a plurality of straight rods, the annular ring is arranged horizontally and detachably arranged in the top of the lower barrel body, the straight rods are arranged along the front and rear directions and are located in the annular ring, the front and rear ends of the straight rods are respectively connected to the annular ring, the plurality of straight rods are arranged at intervals from each other on the left and right, the gravity pressure hammer is arranged vertically, the outer contour of the cross section of the gravity pressure hammer matches the outer contour of the cross section of the upper barrel body, and the gravity pressure hammer is used to be vertically movably inserted in the upper barrel body; The screening and washing device includes an intelligent screen set, and the intelligent screen set includes a first screen and a second screen, the first screen includes a first sleeve, a first screen and a first photoelectric sensor, the first sleeve is vertically arranged, the first screen is horizontally arranged in the first sleeve, the first photoelectric sensor includes a first transmitting end and a first receiving end, the first transmitting end and the first receiving end are relatively spaced apart from each other, the first transmitting end and the first receiving end are both located in the first sleeve and are connected to the first sleeve and are both located under the first screen for detecting dropped objects falling through the first screen, the second screen includes a second sleeve, A second screen and a second photoelectric sensor, the second sleeve is vertically arranged, the second screen is horizontally arranged in the second sleeve, the second photoelectric sensor includes a second transmitting end and a second receiving end, the second transmitting end and the second receiving end are relatively spaced apart on the left and right, the second transmitting end and the second receiving end are both located in the second sleeve and are both connected to the second sleeve and are both located under the second screen for detecting dropped objects falling through the second screen, the upper end of the second sleeve is vertically sleeved outside the lower end of the first sleeve, the aperture of the first screen is 9.5mm, and the aperture of the second screen is 4.75mm.

2. The down-pressure fresh concrete aggregate homogeneity detection system according to claim 1, characterized in that: The diameter of the upper barrel body and the diameter of the lower barrel body are both 100 mm, the height of the upper barrel body is 180 mm, and the barrel depth of the lower barrel body is 80 mm.

3. The down-pressure fresh concrete aggregate homogeneity detection system according to claim 1, characterized in that: The number of the straight rods is 2 or 3.

4. The down-pressure fresh concrete aggregate homogeneity detection system according to claim 1, characterized in that: The air hole is arranged at the center of the bottom of the lower barrel.

5. The down-pressure fresh concrete aggregate homogeneity detection system according to claim 1, characterized in that: The first sleeve and the second sleeve are both square sleeves, and the square sleeves are both arranged in the left-right direction.

6. The down-pressure fresh concrete aggregate homogeneity detection system according to claim 1, characterized in that: The first sleeve includes a first upper sleeve and a first lower sleeve, the first upper sleeve and the first lower sleeve are both vertically arranged, the upper end of the first lower sleeve is vertically sleeved outside the lower end of the first upper sleeve, the first screen is horizontally arranged in the first upper sleeve, the first transmitting end and the first receiving end are both located in the first lower sleeve and are both connected to the first lower sleeve, the second sleeve includes a second upper sleeve and a second lower sleeve, the second upper sleeve and the second lower sleeve are both vertically arranged, the upper end of the second lower sleeve is vertically sleeved outside the lower end of the second upper sleeve, the second screen is horizontally arranged in the second upper sleeve, the second transmitting end and the second receiving end are both located in the second lower sleeve and are both connected to the second lower sleeve, and the upper end of the second upper sleeve is vertically sleeved outside the lower end of the first lower sleeve.

7. A method for detecting the homogeneity of fresh concrete aggregate by downward pressure, characterized in that: The method for detecting homogeneity of aggregates of down-pressed fresh concrete is performed using a down-pressed fresh concrete aggregate homogeneity detection system according to any one of claims 1 to 6 and comprises the following steps: (1) pouring fresh concrete into the upper barrel from the top of the upper barrel, placing the gravity hammer into the upper barrel from the top of the upper barrel and pressing it on the fresh concrete, so that the fresh concrete is accelerated to flow downward, pass through the steel bar simulation mesh and enter the lower barrel until the lower barrel is fully loaded; (2) removing the gravity hammer, the upper barrel, and the steel bar simulation mesh, taking the concrete in the upper barrel as the first sample, and taking the concrete in the lower barrel as the second sample; (3) Weighing the first sample and the second sample of the same mass respectively, and screening them respectively using the intelligent sieve set, wherein the screening process is as follows: placing the first sample or the second sample from the upper end of the first sleeve into the first sleeve and placing it on the first sieve, screening under a flowing water source, and shaking the sieve until the first photoelectric sensor and the second photoelectric sensor detect no dropped objects within a preset time, and the screening is completed; (4) Weighing the mass of the material on the second sieve when screening the first sample and the mass of the material on the second sieve when screening the second sample, respectively, to obtain the mass H1 of the coarse aggregate in the first sample and the mass H2 of the coarse aggregate in the second sample; (5) Calculate the aggregate homogeneity S = H2 / H1×100% after the fresh concrete passes through the steel bar simulation mesh.

8. The method for detecting homogeneity of aggregate of fresh concrete according to claim 7, characterized in that: In step (3), the preset time is 60 seconds.

9. The method for detecting homogeneity of aggregate of fresh concrete according to claim 7, characterized in that: In step (3), the mass of the first sample and the mass of the second sample are both 1000 g.

10. The downward pressure type fresh concrete aggregate homogeneity detection method according to claim 7, characterized in that: In the step (4), the weighing accuracy is to 0.5 g.

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