Downward pressing type fresh concrete aggregate homogeneity detection system and detection method

Abstract

When the downward-pressing type fresh concrete aggregate homogeneity detection system is used, fresh concrete is poured into the upper barrel body, then the gravity pressing hammer is put in, and the fresh concrete is accelerated to flow downwards, passes through the reinforcing steel bar simulation net and enters the lower barrel body until the lower barrel body is fully loaded; respectively taking concrete in the upper and lower barrels, and respectively recording the concrete as a first sample and a second sample; respectively screening the first sample and the second sample with the same mass by adopting an intelligent sieve set, and weighing the mass of the material on the second sieve to respectively obtain the mass H1 and the mass H2 of the coarse aggregate in the first sample and the second sample; and calculating the homogeneity S of the aggregate according to the formula: S = H2 / H1 * 100%. Related detection methods are also provided. The system and the method can simulate the flowing state of the fresh concrete before and after the fresh concrete passes through the steel bar barrier, and screen and measure the coarse aggregate of the concrete before and after flowing, thereby detecting the aggregate homogeneity of the fresh concrete after the fresh concrete passes through the steel bar barrier.

Description

Technical Field

[0001] The present invention relates to the technical field of aggregate homogeneity detection, more specifically, to the technical field of fresh concrete aggregate homogeneity detection, 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 the mix design is unreasonable, the mixing is insufficient, the pumping pressure is too high, the mixing mechanism is unreasonable during transportation, and the waiting time is too long, the various components in the fresh concrete are unevenly distributed in space, which will cause great harm to the concrete structure. In addition, the homogeneity of concrete is prone to change from mixing to mold entry. For example, it is very common that the homogeneity is good when unloading from the mixer truck, but segregation occurs after pumping or long-distance flow. This unevenness will lead to the problem of insufficient local strength of hardened concrete components. According to core sampling and identification, the concrete in these unqualified strength areas is often in a state where coarse aggregate is missing and almost all is mortar. In addition, due to the restraining effect of coarse aggregate, the shrinkage of concrete during the hardening process is much smaller than that of mortar, so the risk of local shrinkage cracking of concrete with poor homogeneity is significantly increased. Based on the above reasons, it is urgent to establish a method for evaluating the homogeneity of fresh concrete to guide commercial concrete premixing plants, improve the homogeneity of fresh concrete, and ensure the structural performance of hardened concrete.

[0004] The existing standard JGJ / T 283-2012 "Technical Specifications for Application of Self-compacting Concrete" uses the vibration method to test the segregation rate for the aggregate uniformity of high-flow self-compacting concrete. This method first loads the self-compacting concrete mixture into the stability test cylinder with a hopper, level it to the hopper mouth, removes the hopper vertically, leaves it to stand for 1 minute, and then removes and smoothes the excess mixture with a spatula. Place the stability test cylinder on a jumping table, turn the crank once per second, and make the jumping table jump 25 times. Remove the stability test cylinder in sections, and load the mixture in each section into a round hole sieve with a hole diameter of 5mm. Rinse the mixture with clean water, sieve out the slurry and fine aggregate, wipe the surface moisture of the remaining coarse aggregate with a sponge, weigh it with a balance, accurate to 1g, and obtain the wet weight of the coarse aggregate in the upper, middle and lower three sections of the mixture: m1, m2 and m3.

[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 carried out 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 only moves under vibration conditions, which cannot simulate the flow state of concrete through the rigid collision of dense steel mesh during actual pouring. This method is difficult to characterize the barrier effect of steel bars on the flowing concrete aggregates, so 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, which 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 bar barriers and screens and measures the coarse aggregates of concrete before and after the flow, thereby detecting the homogeneity of the fresh concrete aggregates after passing through steel bar barriers, and 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 in that it includes a flow device and a screening and washing device, wherein:

[0013] The flow device comprises an upper barrel body, a lower barrel body, a steel bar 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 openings, the bottom of the upper barrel body is detachably arranged on the top of the lower barrel body, the bottom of the lower barrel body is vertically provided with air holes, the steel bar simulation net is arranged horizontally and comprises 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-to-back direction and are located in the annular ring, the front end and the rear end of the straight rods are respectively connected to the annular ring, the plurality of straight rods are arranged at intervals from left to 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 comprises an intelligent screen set, and the intelligent screen set comprises a first screen and a second screen, the first screen comprises 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 comprises 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 both 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 comprises 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 from each other 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 a central position of the bottom of the lower barrel body.

[0018] Preferably, both the first sleeve and the second sleeve are square sleeves, and the square sleeves are arranged along 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 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.

[0020] In a second aspect of the present invention, a method for detecting homogeneity of fresh concrete aggregate by downward pressure is provided, wherein the method is performed by using the aforementioned system for detecting homogeneity of fresh concrete aggregate by downward pressure 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 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 using the intelligent sieve to screen them respectively, the screening process is: putting 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, 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 the first sample is screened and the mass of the material on the second sieve when the second sample is screened, 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% of the freshly mixed concrete after it 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, so that the fresh concrete is accelerated to flow downward, passes through the steel bar simulation net and enters 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, the concrete in the upper barrel is taken out and recorded as the first sample, and the concrete in the lower 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 the intelligent sieve is used for screening respectively, and the screening process is as follows: the first sample or the second sample is taken out and recorded as the second sample. The sample is put 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, so 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 the concrete before and after the flow, so as to detect the aggregate homogeneity of the fresh concrete after passing through the steel bar barrier, which 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 from the top of the upper barrel into the upper barrel, placing a gravity pressure 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 pressure hammer, the upper barrel and the steel bar simulation net, taking the concrete in the upper barrel, recording it as the first sample, and taking the concrete in the lower barrel, recording it as the second sample; weighing the first sample and the second sample of the same mass respectively, and sieving them respectively using the intelligent set sieve, and the screening process is: taking the first sample or the second sample The method is to put the material from the upper end of the first sleeve into the first sleeve and place it on the first sieve, screen it under a flowing water source, 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, and 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, so as to detect the aggregate homogeneity of the fresh concrete after passing through the steel bar barrier, which 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 the means, devices and combinations thereof particularly pointed out in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0034] Figure 2 yes Figure 1 The specific embodiment shown is a schematic diagram of a front cross-sectional exploded view of an intelligent set of screens of a screening and washing device.

[0035] Figure 3 The present invention is a logic flow diagram of the completion of screening determination 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 net; 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 hardened 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 refers to the state in which the coarse aggregate in concrete sinks in the mortar due to gravity, forming a state of uneven spatial distribution. The difference in density between coarse aggregate and mortar, the difference in flow characteristics between coarse aggregate and mortar, and the difference in particle size between coarse aggregate and fine aggregate are the causes of coarse aggregate segregation. These factors have an impact alone 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 concrete aggregates in flow, and make the measured aggregate distribution as similar as possible to that during actual pouring, the inventors, through in-depth and extensive research, invented 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.

[0043] See also Figure 1-2 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 vertically arranged, 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 horizontally arranged and includes an annular ring 6 and a plurality of straight rods 7, the annular ring 6 is horizontally arranged 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 end and the rear end of the straight rod 7 are respectively connected to the annular ring 6, and the plurality of straight rods 7 are spaced apart from each other on the left and right, the gravity pressure hammer 4 is vertically arranged, 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 set of screens, and the intelligent set of screens 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 from each other. 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, the second sleeve 15 is arranged vertically, 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 arranged relatively spaced from left to right, 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 and are both located under the second screen 16 for detecting the dropped objects falling 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. That is, aggregates larger than 4.75mm and smaller than 9.5mm can be determined as coarse aggregates.

[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 the 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, which is defined as an indicator of the degree of aggregate homogeneity maintained after the concrete passes 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 the number of the straight rods 7 is, the denser the steel bars are simulated. The number of the straight rods 7 can be determined as needed. Preferably, the number of the 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 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 direction, can be determined as required. 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 arranged vertically, 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 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, see 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 homogeneity of fresh concrete aggregate by downward pressure, which is performed by using the above-mentioned system for detecting homogeneity of fresh concrete aggregate 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 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) removing the gravity hammer 4, the upper barrel 1 and the steel bar simulation mesh 3, taking the concrete in the upper barrel 1 as the first sample, and taking 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 using the intelligent sieve to screen them respectively, the screening process is: putting 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, screening under a flowing water source, shaking the sieve until the first photoelectric sensor 12 and the second photoelectric sensor 17 do not detect any dropped objects within a preset time, and the screening 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=H2 / H1×100% after the fresh concrete passes through the steel bar simulation mesh. S is a value less than or equal to 1. If S is 100%, it means that the aggregate uniformity of the concrete can remain 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 weighing accuracy can be determined as needed. Preferably, in the step (4), the weighing accuracy 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 in detail. Figure 1-2 The downward pressure fresh concrete aggregate homogeneity detection system shown is used.

[0064] The experimental methods in the following examples without specifying specific conditions are usually 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 meanings 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 method 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) According to the needs, different densities of steel bar simulation meshes 3 are selected to set obstacles. 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 set on the lower barrel 2, the fresh concrete is poured into the upper barrel 1 from the top of the upper barrel 1.

[0070] 2) Place the gravity hammer 4 into the upper barrel 1 from the top and press it on the freshly mixed concrete, so that the concrete is accelerated to flow under pressure, passes through the steel simulation mesh 3 and enters 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) Take away the gravity hammer 4, the upper barrel 1 and the steel simulation mesh 3, and take out 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 use the intelligent sieve of the screening and washing device for screening. The screening process is: put the first sample or the second sample into the first sleeve 10 from the upper end of the first sleeve 10 and place it on the first sieve 11, screen it under flowing water, shake the sieve until the first photoelectric sensor 12 and the second photoelectric sensor 17 do not detect any 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 entirety of the smart 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 the light 24 passes is the detection space. If any object falls from the screen, it will block the light 24 when passing through the detection space, and the receiving end will not receive the light 24. The photoelectric pulse circuit of the photoelectric sensor will generate an electric pulse signal. Each time the light is blocked, an electric pulse signal is generated. If no electric pulse signal is generated, it means that no object has fallen from the screen.

[0078] The photoelectric sensor can be connected to the signal of another control device, and the control device can also be connected to the signal of the vibrator mentioned above. The photoelectric sensor sends an electric pulse signal to the control device. If the electric pulse signal is not 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 logical flow chart for determining the completion of screening can be shown as follows: Figure 3 As shown, the detection logic is: when the screen is shaken, a 60-second countdown starts, and each time a photoelectric sensor determines that there is a falling object, the 60-second countdown starts again; when no falling object is found for 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, accurate to 0.5g, and obtain the mass of coarse aggregate in the first sample H1=318g and the mass of coarse aggregate in the second sample H2=303.5g.

[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 homogeneity of the concrete is in the range of 95%-100%. Under the set working conditions, the coarse aggregate has high homogeneity 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) According to the needs, different densities of steel bar simulation meshes 3 are selected to set obstacles. 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 set on the lower barrel 2, the fresh concrete is poured into the upper barrel 1 from the top of the upper barrel 1.

[0087] 2) Place the gravity hammer 4 into the upper barrel 1 from the top and press it on the freshly mixed concrete, so that the concrete is accelerated to flow under pressure, passes through the steel simulation mesh 3 and enters 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) Take away the gravity hammer 4, the upper barrel 1 and the steel simulation mesh 3, and take out 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 use the intelligent sieve of the screening and washing device for screening. The screening process is: put the first sample or the second sample into the first sleeve 10 from the upper end of the first sleeve 10 and place it on the first sieve 11, screen it under flowing water, shake the sieve until the first photoelectric sensor 12 and the second photoelectric sensor 17 do not detect any 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 entirety of the smart 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 the light 24 passes is the detection space. If any object falls from the screen, it will block the light 24 when passing through the detection space, and the receiving end will not receive the light 24. The photoelectric pulse circuit of the photoelectric sensor will generate an electric pulse signal. Each time the light is blocked, an electric pulse signal is generated. If no electric pulse signal is generated, it means that no object has fallen from the screen.

[0095] The photoelectric sensor can be connected to the signal of another control device, and the control device can also be connected to the signal of the vibrator mentioned above. The photoelectric sensor sends an electric pulse signal to the control device. If the electric pulse signal is not 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, and each time a photoelectric sensor determines that there is a falling object, the 60-second countdown starts again; when no falling object is found for 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, accurate to 0.5g, and obtain the mass of coarse aggregate in the first sample H1=306.5g and the mass of coarse aggregate in the second sample H2=291g.

[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 homogeneity of the concrete is in the range of 90%-95%. Under the set working conditions, the homogeneity of the coarse aggregate is relatively high, and the rebound strength data is relatively stable. When the strength of the specimens 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) According to the needs, different densities of steel bar simulation meshes 3 are selected to set obstacles. 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 set on the lower barrel 2, the fresh concrete is poured into the upper barrel 1 from the top of the upper barrel 1.

[0104] 2) Place the gravity hammer 4 into the upper barrel 1 from the top and press it on the freshly mixed concrete, so that the concrete is accelerated to flow under pressure, passes through the steel simulation mesh 3 and enters 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) Take away the gravity hammer 4, the upper barrel 1 and the steel simulation mesh 3, and take out 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 use the intelligent sieve of the screening and washing device for screening. The screening process is: put the first sample or the second sample into the first sleeve 10 from the upper end of the first sleeve 10 and place it on the first sieve 11, screen it under flowing water, shake the sieve until the first photoelectric sensor 12 and the second photoelectric sensor 17 do not detect any 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 entirety of the smart 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 the light 24 passes is the detection space. If any object falls from the screen, it will block the light 24 when passing through the detection space, and the receiving end will not receive the light 24. The photoelectric pulse circuit of the photoelectric sensor will generate an electric pulse signal. Each time the light is blocked, an electric pulse signal is generated. If no electric pulse signal is generated, it means that no object has fallen from the screen.

[0112] The photoelectric sensor can be connected to the signal of another control device, and the control device can also be connected to the signal of the vibrator mentioned above. The photoelectric sensor sends an electric pulse signal to the control device. If the electric pulse signal is not 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, and each time a photoelectric sensor determines that there is a falling object, the 60-second countdown starts again; when no falling object is found for 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, accurate to 0.5g, and obtain the mass of coarse aggregate in the first sample H1=379.5g and the mass of coarse aggregate in the second sample H2=333g.

[0115] 7) Calculate the aggregate homogeneity S after the fresh concrete passes through the steel simulation mesh 3 = 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 aggregate distribution.

[0117] Therefore, in order to solve the problem of poor uniformity of coarse aggregate in existing high-flow concrete, the present invention designs a system and method for quickly detecting the uniformity of concrete aggregate at the construction site. The system and method can simulate the flow state of high-flow concrete under different steel bar density conditions, intercept the concrete before and after the flow, and use photoelectric sensors for intelligent screening, and finally evaluate the uniformity of concrete aggregate when it flows to the steel bar density after weighing and calculation.

[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, so the authenticity and credibility of aggregate distribution are also improved.

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

[0121] 3. Fast and efficient: The flow is accelerated by the gravity hammer, and the screening is reliably determined by the photoelectric sensor. After the concrete mixture arrives at the test site, the uniformity test result 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, 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.

[0123] In this specification, the present invention has been described with reference to specific embodiments thereof. However, it is apparent that various modifications and variations may be made without departing from the spirit and scope of the present invention. Therefore, the description should 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 comprises an upper barrel body, a lower barrel body, a steel bar 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 openings, the bottom of the upper barrel body is detachably arranged on the top of the lower barrel body, the bottom of the lower barrel body is vertically provided with air holes, the steel bar simulation net is arranged horizontally and comprises 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-to-back direction and are located in the annular ring, the front end and the rear end of the straight rods are respectively connected to the annular ring, the plurality of straight rods are arranged at intervals from left to 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 comprises an intelligent set of screens, and the intelligent set of screens comprises a first screen and a second screen, the first screen comprises 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 comprises 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 both 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 comprises 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 from each other 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 downward pressure fresh concrete aggregate homogeneity detection system according to claim 1 is 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 downward pressure fresh concrete aggregate homogeneity detection system according to claim 1 is characterized in that: The number of the straight rods is 2 or 3.

4. The downward pressure fresh concrete aggregate homogeneity detection system according to claim 1 is characterized in that: The air hole is arranged at the central position of the bottom of the lower barrel body.

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

6. The downward 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-pressure fresh concrete is carried out by using a down-pressure detection system for homogeneity of aggregates of fresh concrete 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 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 using the intelligent sieve to screen them respectively, the screening process is: putting 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, 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 the first sample is screened and the mass of the material on the second sieve when the second sample is screened, 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% of the freshly mixed concrete after it passes through the steel bar simulation mesh.

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

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

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