Method for evaluating quality

Abstract

To provide a method for evaluating quality which can efficiently evaluate the quality of fresh concrete.SOLUTION: A method for evaluating the quality of fresh concrete includes: inserting the tip end of a probe into flesh concrete flowing down a chute; detecting resisting shear generated in the probe by a sensor; and calculating the slump value of the fresh concrete from the detected value of the sensor. The method may include arranging multiple probes and detecting the resisting shear by sensors arranged in the probes and calculating the slump value of the fresh concrete from the detected values of the sensors.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a quality evaluation method, and in particular to a quality evaluation method for fresh concrete. [Background technology]

[0002] Concrete is an essential structural material for construction and civil engineering works. The ingredients of concrete are binder (cement), aggregate (gravel, sand, crushed stone, crushed sand, etc.), water, and admixtures, which are mixed before construction according to the desired strength, durability, workability, etc. Fresh concrete, which is made by mixing the ingredients, is produced in a batcher plant, and is transported to the construction site by an agitator truck, while being mixed so that the fresh concrete does not harden. At the construction site, formwork is constructed to maintain the shape of the fresh concrete until it hardens, and after the fresh concrete is poured, it is cured in the formwork for a specified time until it hardens.

[0003] The fluidity of fresh concrete can be measured by a slump test. A larger slump indicates higher fluidity of fresh concrete. Since the slump test of fresh concrete is a random inspection, there is a risk that poor quality fresh concrete will be overlooked. However, since the slump test is a manual task, it is not reasonable to inspect all samples.

[0004] For example, Patent Document 1 discloses a concrete management system that predicts workability based on captured images of concrete. Patent Document 2 discloses a quality evaluation method that determines the quality of fresh concrete by capturing an image of the fresh concrete flowing along an inclined surface, recognizing the surface of the fresh concrete flowing down from the video, and calculating the inclination of the surface shape of the fresh concrete. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2021-172011 A [Patent Document 2] JP 2020-142398 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the evaluation methods described in Patent Documents 1 and 2 may not be able to perform an appropriate evaluation depending on the level of light exposure.

[0007] An object of the present invention is to provide a quality evaluation method capable of efficiently evaluating the quality of fresh concrete. [Means for solving the problem]

[0008] A method for evaluating the quality of fresh concrete in one embodiment of the present invention includes inserting the tip of a probe into fresh concrete flowing down a chute, detecting the shear resistance generated in the probe with a sensor, and calculating a slump value of the fresh concrete from the detection value of the sensor.

[0009] The method may include arranging a plurality of probes, detecting shear resistance with a plurality of sensors arranged on each of the probes, and calculating a slump value of the fresh concrete from detection values ​​of the plurality of sensors.

[0010] Each of the multiple probes may be a cantilever having a rod-like or plate-like fixed end, and may be disposed perpendicular to the inclination of the inclined surface.

[0011] The multiple probes may be arranged side by side perpendicular to the direction in which the fresh concrete flows downward.

[0012] The multiple sensors may be strain gauges that detect strain on each of the multiple probes.

[0013] Each of the multiple probes may have a different stiffness.

[0014] Each of the multiple probes may have a different width perpendicular to the direction in which the fresh concrete flows downward.

[0015] Each of the multiple probes may have a different Young's modulus.

[0016] Each of the multiple probes may have a different thickness parallel to the direction in which the fresh concrete flows downward. Effect of the Invention

[0017] According to one embodiment of the present invention, it is possible to provide a quality evaluation method capable of efficiently evaluating the quality of fresh concrete. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of an agitator truck according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram showing a configuration of a chute and a probe according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a front view showing a configuration of a probe according to an embodiment of the present invention. [Figure 4] 1 is a side view showing a configuration of a probe according to an embodiment of the present invention; [Diagram 5] FIG. 1 is a diagram illustrating an example of a quality evaluation method for fresh concrete according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The method for evaluating the quality of fresh concrete of the present invention will be described below with reference to the drawings. However, the method for evaluating the quality of fresh concrete of the present invention can be implemented in many different ways, and should not be interpreted as being limited to the description of the examples shown below. In the drawings referred to in this embodiment, the same parts or parts having similar functions are designated by the same reference numerals or the same reference numerals followed by alphabets, and repeated explanations thereof will be omitted.

[0020] In this specification, "up" refers to a direction perpendicular to the inclined surface of the chute, "down" refers to a direction perpendicular to the inclined surface of the chute, "front" refers to the upstream direction in which fresh concrete flows down, and "rear" refers to the downstream direction in which fresh concrete flows down.

[0021] [Agitator truck configuration] Hereinafter, the schematic configuration of the agitator truck 100 according to one embodiment will be described with reference to Figs. 1 and 2. Fig. 1 is a diagram showing the configuration of the agitator truck 100 according to one embodiment. Fig. 2 is a diagram showing the configuration of a chute and a probe according to one embodiment. In this embodiment, the agitator truck 100 is illustrated as an example, but the present invention is not limited to this example. The present invention can also be applied to other devices that handle fresh concrete, such as mixer trucks and mixers in batcher plants.

[0022] The agitator truck 100 according to this embodiment includes a detection unit 1 that detects the resistance of fresh concrete, a hopper 10, a drum 20, a flow guide 30, and a chute 40.

[0023] The hopper 10 is disposed at the upper rear of the agitator truck 100, and is an inlet through which fresh concrete produced in the batcher plant is poured into the drum 20. A cover may be placed on the top of the hopper 10 to ensure quality, such as by preventing the intrusion of foreign matter.

[0024] The drum 20 is a barrel-shaped container for loading fresh concrete. The drum 20 can rotate even while traveling, preventing separation of aggregate and water and keeping the fresh concrete homogeneous.

[0025] The flow guide 30 receives the fresh concrete discharged from the drum 20. The fresh concrete discharged into the flow guide 30 flows down into a chute 40 connected to the bottom thereof.

[0026] The chute 40 is a gutter for pouring fresh concrete into a formwork, with one end fixed to the flow guide 30. The other end opposite the end fixed to the flow guide 30 can be moved left and right and up and down. The chute 40 has a semi-cylindrical shape, and is arranged so that the extension direction (axial direction) from one end to the other end is inclined with respect to the ground and the vertical direction. The opening of the chute 40 is arranged facing upward, and the fresh concrete flows down in contact with the inclined surface of the chute 40. The detection unit 1 is arranged at the opening of the chute 40.

[0027] [Detection unit configuration] FIG. 2 is a diagram showing the configuration of the chute 40 and the detection unit 1 of the agitator truck 100 according to one embodiment. FIG. 3 is a front view showing the configuration of the probe according to one embodiment, and FIG. 4 is a side view showing the configuration of the probe according to one embodiment. As shown in FIGS. 2 to 4, the detection unit 1 includes a holding member 2, a probe 3, and a sensor 4. In this embodiment, the holding member 2 of the detection unit 1 is fixed on the chute 40 and crosses the diameter direction of the opening. The holding member 2 of the detection unit 1 is arranged perpendicular to the direction in which the fresh concrete flows down (indicated by the arrow).

[0028] The holding member 2 holds the probe 3. The probe 3 is a cantilever beam having a fixed end fixed to the holding member 2, and is composed of a rod-shaped or plate-shaped member. When the probe 3 is rod-shaped, it may be, for example, a column or a cone, and its axis may be straight or curved. When the probe 3 is plate-shaped, it may have, for example, a flat surface, a gently curved surface, two or more flat surfaces, or a combination of a flat surface and a curved surface. The probe 3 extends downward from the holding member 2. The probe 3 is disposed substantially perpendicularly with the fixed end facing up with respect to the inclination (axial direction) of the inclined surface of the chute 40. The free end of the probe 3 opposite the fixed end is installed perpendicular to the fresh concrete flowing down the chute 40. For this reason, the free end of the probe 3 opposite the fixed end is adjusted so as to be inserted at a predetermined depth into the fresh concrete flowing down the chute 40. The free end of the probe 3 opposite the fixed end does not need to come into contact with the inclined surface of the chute 40. The probe 3 preferably has a length that allows the probe 3 to be elastically deformed (bend) as the fresh concrete flows down.

[0029] In this embodiment, the probe 3 includes a cold-rolled steel plate (SPC material). However, the probe 3 is not limited to this, and may be any member having sufficient elasticity to be elastically deformed (bend) by fluid force when inserted into fresh concrete flowing down the chute 40. The probe 3 may be any member formed of metal, plastic, wood, fiber-reinforced composite material, or the like. The Young's modulus of the probe 3 is preferably in the range of 10 GPa or more and 400 GPa or less, for example.

[0030] It is preferable that a plurality of probes 3 are arranged. It is more preferable that three or more probes 3 are arranged. In this embodiment, four probes 3a, 3b, 3c, 3d (when the four probes 3a, 3b, 3c, 3d are not distinguished from each other, they are referred to as probes 3) are arranged. The four probes 3a, 3b, 3c, 3d are fixed to the holding member 2 independently. The four probes 3a, 3b, 3c, 3d are arranged in a line in the diameter direction of the opening of the chute 40. That is, the four probes 3a, 3b, 3c, 3d are arranged in a single horizontal row in a direction perpendicular to the direction (arrow) in which the fresh concrete flows down. However, the present invention is not limited to this, and the plurality of probes 3 may be arranged in front of and behind the direction (arrow) in which the fresh concrete flows down, and for example, two probes 3 each may be arranged in two horizontal rows in a direction perpendicular to the direction (arrow) in which the fresh concrete flows down. By arranging a plurality of probes 3, the state of the fresh concrete can be detected in more detail.

[0031] It is preferable that the four probes 3a, 3b, 3c, and 3d have different rigidities. The rigidities of the four probes 3a, 3b, 3c, and 3d can be changed by appropriately selecting one or more of the elastic modulus, thickness, length, and width. For example, the four probes 3a, 3b, 3c, and 3d may have different widths in a direction perpendicular to the direction in which the fresh concrete flows down (arrows). The four probes 3a, 3b, 3c, and 3d may have different Young's moduli. The four probes 3a, 3b, 3c, and 3d may have different thicknesses in a direction parallel to the direction in which the fresh concrete flows down (arrows).

[0032] As the fresh concrete flows down, the free end of the probe 3 shears the fresh concrete. At this time, the probe 3 receives shear resistance and undergoes elastic deformation in the direction in which the fresh concrete flows down (arrow). If the fresh concrete is hard (low fluidity), the shear resistance increases and the probe 3 deforms significantly. On the other hand, if the fresh concrete is soft (high fluidity), the shear resistance decreases and the deformation of the probe 3 decreases.

[0033] The probe 3 is a member for detecting the shear resistance occurring in the probe 3 when the fresh concrete flows down along the inclined surface of the chute 40, and is not limited to the configuration of this embodiment as long as it is configured to detect the load capacity of the fresh concrete due to differences in the quality of the fresh concrete. In other words, it is sufficient that the member constituting the probe is deformed by the flow of fresh concrete down, and the shear resistance can be detected based on the amount of deformation.

[0034] The detection unit 1 has a sensor 4 and has a function of detecting deformation of the probe 3 due to shear resistance. The sensor 4 may be, for example, a strain gauge. The sensor 4 is disposed under the fixed end of the probe 3, in front of and behind the direction (arrow) in which the fresh concrete flows down. The sensor 4 may be disposed at a position where the deformation of the probe can be appropriately measured, for example, between 1 cm from the fixed end of the probe 3 and 1 cm from the end of the free end of the probe, and is preferably disposed in the center excluding 1 cm from each of both ends. The sensor 4 is more preferably disposed on the fixed end side of the center. By disposing the sensor 4 within the above range, it is possible to accurately detect the elastic deformation of the probe 3 due to the stress of the fresh concrete flowing down. However, the present invention is not limited to this, and the sensor 4 may be disposed either in front of or behind the direction (arrow) in which the fresh concrete flows down as long as it does not come into direct contact with the flowing fresh concrete. The sensor 4 (strain gauge) fixed to the probe 3 has a resistor that expands and contracts in accordance with the deformation (strain) of the probe 3, changing its electrical resistance. This change in electrical resistance is measured and converted into the amount of deformation of the probe 3 .

[0035] In this embodiment, a strain gauge is used as a means for detecting the deformation of the probe 3, but the present invention is not limited to this, and instead of the strain gauge, for example, an acceleration sensor, a gyro sensor, a magnetic sensor, a potentiometer, or the like may be used.

[0036] [Quality evaluation method for fresh concrete] Here, a method for evaluating the quality of fresh concrete based on the detection result from the detection unit 1 will be described. In the method for evaluating the quality of fresh concrete according to this embodiment, the state of fresh concrete discharged from the drum 20 of the agitator truck 100 and flowing down along the inclined surface of the chute 40 is detected by the detection unit 1. Specifically, the amount of deformation occurring in the probe 3 when the fresh concrete flows down is detected by the sensor 4. The probe 3 is elastically deformed by the load force received from the flowing fresh concrete. The load force received from the fresh concrete changes depending on the state of the fresh concrete, and the amount of deformation of the probe 3 changes accordingly. For example, if the fresh concrete is in a hard state (low fluidity), the amount of deformation (shear resistance) of the probe 3 is large, and if the fresh concrete is in a soft state (high fluidity), the amount of deformation (shear resistance) of the probe 3 is small. The amount of deformation (shear resistance) of the probe 3 is acquired based on the detection result from the sensor 4, and the quality of the fresh concrete is determined based on the data.

[0037] In this embodiment, for example, the load (shear resistance of the probe 3) of the flowing fresh concrete is calculated from the data value acquired from the sensor 4 (strain gauge) using the following formula. P = εEbh2 / (6L) Where ε: Dynamic strain of probe 3 (average for 1 second) P: Loading force due to fresh concrete (shear resistance of insertion needle) (N) L: Length from the virtual loading point to the strain gauge (mm) E: Young's modulus of probe 3 (assumed to be 200000N / mm2) b: width of probe 3 (mm) h: thickness of probe 3 (mm)

[0038] For example, when the width of probe 3a is 3 mm, the width of probe 3b is 24 mm, the width of probe 3c is 12 mm, and the width of probe 3d is 6 mm, the results of plotting the shear resistance (Y axis, n = 7) against the width of probe 3 (X axis) are shown in Figure 5. The intercept value (X = 0) of each sample and its average are shown in Table 1. [Table 1]

[0039] After obtaining the average of the intercepts to which each sample converges from the deformation amount (shear resistance) of the probe 3, this is classified into one of a number of pre-labeled fresh concrete qualities to determine the quality of the fresh concrete. The labeling may be, for example, three levels, or more. In this case, the finer the labeling, the more precisely the quality of the fresh concrete can be determined, but it is desirable to perform appropriate labeling depending on the application. In this embodiment, a reference table that directly associates the average of the intercepts to which each sample converges with the labels is obtained in advance, and the labels are determined using the reference table.

[0040] As described above, the quality evaluation method of fresh concrete according to this embodiment can directly detect the state of the fresh concrete discharged from the drum 20 of the agitator truck 100 and flowing down the inclined surface of the chute 40 by the detection unit 1, thereby enabling efficient quality evaluation of the fresh concrete.

[0041] In the present embodiment, the method for evaluating the quality of fresh concrete has been described, but the present invention is not limited to this example. For example, the rotation direction or rotation speed of the drum 20 may be changed depending on the quality of the fresh concrete. Also, a label according to the quality of the fresh concrete may be displayed on a remote control or a mobile terminal to notify the user of the quality of the fresh concrete. In this case, the user may adjust the discharge of the fresh concrete by operating the remote control or the like based on the displayed label.

[0042] Although the present invention has been described above with reference to the drawings, the present invention is not limited to the above-mentioned embodiments, and can be modified as appropriate without departing from the spirit of the present invention. For example, a person skilled in the art can add, delete, or modify components based on each embodiment as appropriate, and the scope of the present invention is included as long as the gist of the present invention is met. Furthermore, the above-mentioned embodiments can be combined as appropriate as long as there is no mutual contradiction, and technical matters common to each embodiment are included in each embodiment even if not explicitly stated.

[0043] Even if there are other effects and advantages different from those brought about by the aspects of each of the above-mentioned embodiments, those which are clear from the description in this specification or which can be easily predicted by a person skilled in the art are naturally understood to be brought about by the present invention. [Explanation of symbols]

[0044] 1 detection unit, 2 holding member, 3 probe, 4 sensor, 10 hopper, 20 drum, 30 flow guide, 40 chute, 100 agitator track

Claims

1. The tip of the probe is inserted into the fresh concrete flowing down the chute. Detecting the shear resistance generated in the probe with a sensor; Calculating a slump value of the fresh concrete from the detection value of the sensor; Quality assessment methods including:

2. A plurality of the probes are arranged, and a plurality of sensors are arranged in each of the probes to detect shear resistance; Calculating a slump value of the fresh concrete from the detection values ​​of the plurality of sensors; The quality evaluation method according to claim 1 , comprising:

3. The quality evaluation method according to claim 2 , wherein each of the plurality of probes is a cantilever having a rod-shaped or plate-shaped fixed end and is arranged perpendicular to the inclination of the chute.

4. The quality evaluation method according to claim 2 , wherein the plurality of probes are arranged perpendicular to a direction in which the fresh concrete flows downward.

5. The quality evaluation method according to claim 2 , wherein the plurality of sensors are strain gauges that detect strain in each of the plurality of probes.

6. The quality evaluation method according to claim 2 , wherein each of the plurality of probes has a different stiffness.

7. The quality evaluation method according to claim 6 , wherein each of the plurality of probes has a different width perpendicular to a direction in which the fresh concrete flows down.

8. The quality assessment method according to claim 6 , wherein each of the plurality of probes has a different Young's modulus.

9. The quality evaluation method according to claim 6 , wherein each of the plurality of probes has a different thickness parallel to a direction in which the fresh concrete flows down.

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