Quality evaluation device for fresh concrete and quality evaluation method for fresh concrete

Abstract

To evaluate slump of fresh concrete correctly.SOLUTION: A quality evaluation device for fresh concrete has: a chute in which fresh concrete flows; a plurality of probes which is supported by a bottom face of the chute, and extends in a vertical direction to the bottom face; and sensors each of which is provided in the probe. The device measures shear resistance which occur on the probes by the sensors. The probes may be arranged in a direction crossing a direction where the fresh concrete flows down in the chute, and may be arranged in a direction parallel to the direction where the fresh concrete flows in the chute.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] An embodiment of the present invention relates to an apparatus for assessing the quality of fresh concrete and a method for assessing the quality of fresh concrete. [Background technology]

[0002] Concrete is a structural material used in civil engineering and building construction. Concrete ingredients consist of binder (cement), aggregate (gravel, sand, crushed stone, crushed sand, etc.), water, admixtures, etc., and these ingredients are mixed according to the desired strength, durability, workability, etc. before being poured. Fresh concrete is produced in a batcher plant and transported to the pouring site by agitator trucks, stirring the fresh concrete to prevent it from hardening. At the pouring site, the fresh concrete is poured into forms and left to cure until it hardens.

[0003] Quality control of fresh concrete is important to prevent variations in the quality of concrete structures. The quality of fresh concrete can be evaluated based on its fluidity, which can be measured by a slump test. The slump value obtained from a slump test is a numerical value that indicates the fluidity (softness) of fresh concrete, and a higher slump value indicates higher fluidity of the fresh concrete. It is preferable to conduct a slump test on all fresh concrete that is poured, but in reality, it is conducted as a random inspection from the perspective of rationalization.

[0004] Therefore, methods for evaluating fresh concrete as an alternative to slump tests have been proposed. For example, Patent Document 1 discloses a concrete management system that predicts workability based on photographed images of fresh concrete. Patent Document 2 discloses a quality evaluation method that determines the quality of fresh concrete by photographing fresh concrete flowing along an inclined surface, recognizing the surface of the flowing fresh concrete from the photographed images (video), and calculating the slope of the surface shape. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-172011 [Patent Document 2] Japanese Patent Application Publication No. 2020-142398 Summary of the Invention [Problem to be solved by the invention]

[0006] However, since the evaluation methods disclosed in Patent Documents 1 and 2 are based on images, there is a risk that accurate evaluation will not be possible because the image quality will change depending on environmental conditions such as the weather at the time of shooting and the brightness of the construction site, as well as shooting conditions such as exposure and focusing. [Means for solving the problem]

[0007] A fresh concrete evaluation device according to one embodiment of the present invention has a chute through which fresh concrete flows, a plurality of probes supported at the bottom of the chute and extending perpendicular to the bottom, and sensors attached to the plurality of probes, and is configured to measure the shear resistance generated in the probes using the sensors.

[0008] In one embodiment of the present invention, the multiple probes may be arranged in a direction that intersects the direction in which the fresh concrete flows down in the chute, or may be arranged in a direction that is parallel to the direction in which the fresh concrete flows down in the chute.

[0009] In one embodiment of the present invention, the plurality of probes may have different widths and different Young's moduli.

[0010] In one embodiment of the present invention, the fresh concrete evaluation device may have a support part that supports the chute at an angle inclined at a predetermined angle.

[0011] A method for evaluating fresh concrete according to one embodiment of the present invention includes measuring the shear resistance generated in a plurality of probes extending upward from the bottom of a chute through which the fresh concrete flows as the fresh concrete flows down the chute, and evaluating the slump value of the fresh concrete from the measured value.

[0012] In one embodiment of the present invention, the method includes measuring the shear resistance using a plurality of probes and estimating the slump value of the fresh concrete from the measured values.

[0013] In one embodiment of the present invention, each of the multiple probes is a cantilever beam having a rod-like or plate-like shape, and measures the shear resistance while being positioned perpendicular to the bottom surface of the chute.

[0014] In one embodiment of the present invention, a plurality of probes have different widths, and the shear resistance values ​​measured for each of the different widths are plotted on a graph, and the intercept of the line drawn by the plot when extrapolated is taken as the shear resistance. [Effects of the Invention]

[0015] According to the fresh concrete quality evaluation device and evaluation method of one embodiment of the present invention, the slump can be estimated with high accuracy, regardless of the flow rate of fresh concrete. Furthermore, since measurement is possible by placing this quality evaluation device on the extension line of the chute of the agitator vehicle, there is no need to re-install it for each agitator vehicle, which increases applicability to construction sites. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a diagram showing the configuration of a fresh concrete evaluation device according to one embodiment of the present invention. [Figure 2] 1 is a perspective view showing the configuration of a fresh concrete evaluation device according to one embodiment of the present invention. FIG. [Figure 3] 1 is a side view showing a probe included in an apparatus for evaluating fresh concrete according to an embodiment of the present invention. FIG. [Figure 4] FIG. 2 is a diagram showing the arrangement of probes in the fresh concrete evaluation device according to one embodiment of the present invention. [Figure 5] FIG. 2 is a diagram showing the arrangement of probes in the fresh concrete evaluation device according to one embodiment of the present invention. [Figure 6] FIG. 1 is a diagram showing an embodiment of the fresh concrete evaluation device according to the present invention; [Figure 7] 1 is a graph showing the shear resistance value of a probe measured by the fresh concrete evaluation device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention can be implemented in many different forms, and should not be construed as being limited to the description of the embodiments exemplified below. For clarity of explanation, the drawings may show the length, width, height, thickness, shape, etc. of each part schematically compared to the actual form, but these are merely examples and do not limit the interpretation of the present invention. Furthermore, in this specification and each drawing, elements similar to those previously described with reference to the previous drawings may be designated by the same reference numerals (or reference numerals with A, B, etc. suffixed thereto), and detailed description may be omitted as appropriate. Furthermore, the letters "first" and "second" attached to each element are convenient labels used to distinguish each element and have no further meaning unless otherwise specified.

[0018] 1(A) to 1(C) show the configuration of a fresh concrete quality evaluation device 100 (hereinafter simply referred to as "quality evaluation device 100") according to one embodiment of the present invention. Fig. 1(A) shows a plan view of the quality evaluation device 100, (B) shows a front view, and (C) shows a side view.

[0019] The quality evaluation device 100 includes a chute 102 that forms a flow path for fresh concrete, and a detection unit 104 provided in the chute 102. The detection unit 104 includes at least one probe and a sensor provided in the at least one probe. FIGS. 1(A) to 1(C) show four probes (first probe 106A, second probe 106B, third probe 106C, and fourth probe 106D) and four sensors (first sensor 108A, second sensor 108B, third sensor 108C, and fourth sensor 108D), but in the following description, when there is no need to distinguish between these probes and sensors, they will simply be referred to as probes 106 and sensors 108.

[0020] 1(A) shows four probes 106, but there is no limitation on the number of probes. It is preferable that a plurality of probes 106 be provided on the chute 102.

[0021] The chute 102 may have a channel-like shape like a gutter, or may be tubular. While FIG. 1(B) shows a structure in which the bottom of the chute 102 (the bottom of the flow path for fresh concrete) is flat, the bottom of the chute 102 may also be curved. The chute 102 is supported at an angle to allow the fresh concrete to flow. For example, as shown by the arrows in FIG. 1(A), when fresh concrete flows from the left to the right of the chute 102, the chute 102 is supported at an angle so that the left side is higher and the right side is lower. The angle θ at which the chute 102 is supported may be set as appropriate, but for example, the chute 102 is supported at an inclination angle of 30 to 90 degrees relative to the horizontal. By maintaining a constant angle θ at which the chute 102 is supported, it is possible to perform a relative evaluation of each site where fresh concrete is poured.

[0022] There is no limitation on the structure that supports the chute 102, and for example, a support base 110 that supports the chute 102 at an angle from below may be used. There is no limitation on the shape or structure of the support base 110, and it may have a box-like shape or a structure assembled with a frame. Although not shown, the chute 102 may be supported by being suspended at an angle from above.

[0023] The probe 106 has a plate-like, rod-like, or needle-like shape. The probe 106 preferably has a length that allows the entire probe 106 to be submerged in the fresh concrete when the fresh concrete is poured into the chute 102. The probe 106 is attached to the bottom of the chute 102 so as to extend upward. The angles of the probes 106 (first probe 106A, second probe 106B, third probe 106C, and fourth probe 106D) are preferably constant and the same, and for example, the probes 106 are preferably set up perpendicular to the bottom of the chute 102 in a cross-sectional view. In other words, the probes 106 are preferably set up in a direction inclined by 90 degrees with respect to the angle θ of the chute 102.

[0024] The probes 106 (first probe 106A, second probe 106B, third probe 106C, fourth probe 106D) elastically deform when fresh concrete flows into the chute 102, and the magnitude of this deformation (strain) is detected by each sensor (first sensor 108A, second sensor 108B, third sensor 108C, fourth sensor 108D). There are no limitations on the arrangement of the probes 106 (first probe 106A, second probe 106B, third probe 106C, fourth probe 106D), but it is preferable that they are arranged at a distance so as not to come into contact with each other.

[0025] FIG. 2 shows a perspective view of the detection unit 104. FIG. 2 shows the configuration of the detection unit 104, including a first probe 106A, a second probe 106B, a third probe 106C, and a fourth probe 106D, and a first sensor 108A, a second sensor 108B, a third sensor 108C, and a fourth sensor 108D attached to each probe. When the external shape of the probe 106 is plate-like, the shape may have two or more flat surfaces, a gently curved surface, or a combination of flat and curved surfaces. When the probe 106 is rod-shaped, the external shape may be linear or curved.

[0026] First probe 106A, second probe 106B, third probe 106C, and fourth probe 106D have one longitudinal end (lower end) fixed to support 107 and the other end (upper end) as a free end. In other words, probe 106 has a configuration similar to that of a cantilever beam. As will be described later, probe 106 has elasticity, and so is deformed to bend when an external force is applied.

[0027] Support portion 107 may be the bottom surface of chute 102 itself, or may be a plate- or rod-shaped member that can be attached (or detached) to the bottom surface of chute 102. When support portion 107 is a plate- or rod-shaped member, it preferably has a thickness that does not significantly affect the flow of fresh concrete.

[0028] 3(A) and (B) show details of the probe 106. Here, FIG. 3(A) shows a front view of the probe 106, and FIG. 3(B) shows a side view of the probe 106.

[0029] 3A and 3B show an example of a probe 106 formed from a plate-like member, with the probe 106 having a length L, a width W, and a thickness T. Here, the length L is the linear distance from one end of the probe 106 to the other, the width W is the length normal to the direction in which the fresh concrete flows, and the thickness T is the length parallel to the direction in which the fresh concrete flows. The probe 106 has, for example, a length L ranging from 50 mm to 200 mm, a width W ranging from 2 mm to 30 mm, and a thickness T ranging from 2 mm to 5 mm. Although not shown, when the probe 106 has a rod-like or needle-like shape, the diameter can be in the range of 2 mm to 30 mm. Note that the dimensions of the probe 106 shown above are merely examples and can be set appropriately taking into account the material of the member forming the probe 106, the shape of the chute through which the fresh concrete flows, the flow rate, and the like.

[0030] The probe 106 is made of an elastic material, such as a metal material, a plastic material, wood, or a fiber-reinforced composite material. For example, the probe 106 can be made of cold-rolled steel plate (SPC material). If the degree of elasticity of the probe 106 is expressed in Young's modulus, the Young's modulus is preferably in the range of 10 GPa or more and 400 GPa or less.

[0031] There is no limitation on the method of fixing the probe 106 to the support part 107. The lower end of the probe 106 may be joined to the support part 107 by welding or by adhesive. In either joining method, it is preferable that the probe 106 is firmly fixed so that it does not tilt or fall over due to the flow of fresh concrete.

[0032] A probe 106, supported at its bottom like a cantilever beam, is installed in the chute 102, and as the fresh concrete flows down, the probe 106 shears the fresh concrete. Because fresh concrete is viscous, the probe 106 experiences shear resistance and elastically deforms in the direction the fresh concrete flows down. When the fresh concrete is hard (low fluidity), the shear resistance increases, and the probe 106 undergoes large elastic deformation. On the other hand, when the fresh concrete is soft (high fluidity), the shear resistance decreases, and the elastic deformation of the probe 106 decreases.

[0033] The sensor 108 has a function of detecting the magnitude of elastic deformation (or strain) of the probe 106. A strain gauge that measures the amount of strain based on a change in electrical resistance may be used as the sensor 108. Alternatively, an acceleration sensor, a gyro sensor, a magnetic sensor, a potentiometer, or the like may be used as the sensor 108.

[0034] As shown in FIG. 3(B), when fresh concrete flows in the direction of the arrow, the sensor 108 may be provided both upstream and downstream of the flow of fresh concrete. The sensor 108 may be attached at any position where the elastic deformation of the probe 106 can be appropriately measured. The sensor 108 is preferably placed, for example, between 10 mm from the fixed end of the probe 106 and 10 mm from the free end of the probe 106. By placing the sensor 108 within this range, it becomes possible to accurately detect the amount of elastic deformation of the probe 106 caused by the force acting when the fresh concrete flows downward.

[0035] As shown in FIG. 3(B), sensors 108 (first sensor 108A and second sensor 108B) may be provided at two locations on the probe 106. For example, the first sensor 108A may be provided on the upstream surface of the probe 106 (the surface on which the fresh concrete flows), and the second sensor 108B may be provided on the downstream surface (the surface on which the fresh concrete flows away). Although not shown, the sensor 108 may be provided on only one of the upstream and downstream surfaces of the probe 106.

[0036] The probe 106 is used to detect the shear resistance generated in the probe 106 when the fresh concrete flows down the chute 102, and to evaluate the slump of the fresh concrete based on the detected value. The configurations of the probe 106 and the sensor 108 only need to have a configuration capable of detecting the shear resistance generated by the flowing fresh concrete, and are not limited to the configurations shown in FIGS. 3(A) and (B).

[0037] <000015-!>Referring to FIG. 2 again, a plurality of probes 106 having different widths W and / or thicknesses T are arranged in the detection unit 104. FIG. 2 shows the first probe 106A, the second probe 106B, the third probe 106C, and the fourth probe 106D, which preferably have different rigidities (ease of elastic deformation) from each other. The rigidity of the probe 106 can be changed by external dimensions such as the width W and the thickness T. Also, the rigidity of the probe 106 can be changed by using materials with different Young's moduli. For example, as shown in FIG. 2, when the first probe 106A has a width WA, the second probe 106B has a width WB, the third probe 106C has a width WC, and the fourth probe 106D has a width WD, the widths WA, WB, WC, WD are different from each other. For example, by making the relationship WA < WB < WC < WD hold, the rigidity of each probe 106 can be changed. Note that FIG. 2 shows an example in which probes 106 having different widths W are arranged in the detection unit 104 in the direction in which the fresh concrete flows, but probes 106 having a constant width W and different thicknesses T may be arranged.

[0038] In this way, the magnitude of shear resistance and the magnitude of elastic deformation change due to the different widths of the probes 106. Although not shown, the thickness T of each probe 106 may be different from each other, or the width W and thickness T may be different from each other. Also, although not shown, the probes 106 may have the same outer diameter dimension but different rigidities (Young's moduli).

[0039] Probe 106 extends upward from support portion 107. As described with reference to FIGS. 1(A) to 1(C), probe 106 is positioned so that its free end (tip) faces approximately perpendicular to the bottom surface (inclined surface) of chute 102. Probe 106 elastically deforms as fresh concrete flows down, and the magnitude of this deformation is detected by sensor 108.

[0040] 2, when the first probe 106A, second probe 106B, third probe 106C, and fourth probe 106D have different widths, the shear resistance caused by the flow of fresh concrete differs, and therefore the magnitude of elastic deformation measured by each probe also differs.In this way, the quality evaluation device 100 has the function of evaluating the quality of fresh concrete from the magnitude of shear resistance measured by multiple probes 106 with different rigidities.

[0041] Figures 4(A) and (B) and Figures 5(A) and (B) show an example of the arrangement of the first probe 106A, second probe 106B, third probe 106C, and fourth probe 106D provided on the chute 102. Figures 4(A) and (B) and Figures 5(A) and (B) show the arrangement of each probe 106 on the chute 102, and the direction of the arrows shown in each figure is assumed to be the direction in which the fresh concrete flows. Furthermore, the first probe 106A has a width WA, the second probe 106B has a width WB, the third probe 106C has a width WC, and the fourth probe 106D has a width WD.

[0042] FIG. 4(A) shows the arrangement of the first probe 106A, second probe 106B, third probe 106C, and fourth probe 106D in FIG. 2. The first probe 106A and the second probe 106B are arranged side by side near the center of the chute 102, with the third probe 106C arranged downstream of these probes on the outer left and the fourth probe 106D arranged on the outer right. FIG. 4(B) shows the arrangement of the probes 106 shown in FIG. 4(A) with the first probe 106A, the second probe 106B, the third probe 106C, and the fourth probe 106D rotated 90 degrees. The probes 106 are sensing units for measuring the slump of fresh concrete, but they also present a flow obstacle to the flowing fresh concrete. As shown in FIGS. 4(A) and (B), it is preferable to arrange the probes so that they do not overlap with the flow of fresh concrete.

[0043] Fig. 5(A) shows an example in which the first probe 106A, the second probe 106B, the third probe 106C, and the fourth probe 106D are arranged in a horizontal row. Fig. 5(B) shows an example in which the first probe 106A, the second probe 106B, the third probe 106C, and the fourth probe 106D are arranged in a vertical row. Even when such an arrangement is used, by arranging them with sufficient spacing, it is possible to avoid impeding the flow of fresh concrete.

[0044] 6 is a schematic diagram showing an aspect of a fresh concrete quality evaluation device 100 when it is placed at a concrete pouring site. The quality evaluation device 100 is placed between a chute 202 of an agitator vehicle 200 that transports fresh concrete and a hopper 210. In other words, the quality evaluation device 100 is placed so that the chute 102 of the quality evaluation device 100 is connected to the chute 202 of the agitator vehicle 200, and the hopper 210 is located at the end of the chute 102. The hopper 210 may be the hopper of a concrete pump vehicle. Furthermore, the end of the chute 102 may be a formwork into which concrete is poured directly, instead of the hopper 210.

[0045] In the arrangement shown in Fig. 6, the chute 102 of the quality evaluation device 100 is arranged at an angle to allow the fresh concrete to flow. As described with reference to Fig. 1(C), the chute 102 may be placed on a support stand 110 so that the angle is maintained constant. The support stand 110 may have a mechanism that can adjust the angle of the chute 102. The chute 102 may also be configured in multiple stages so that its length can be adjusted.

[0046] In this way, by holding the chute 102 on the support base 110, it is possible to relatively evaluate the quality of fresh concrete even when the construction site changes. The chute 102 is provided with a detection unit 104 shown in Figures 1(A) to 1(C), which makes it possible to evaluate the quality of the fresh concrete on the spot when it is supplied from the agitator vehicle 200 to the hopper 210.

[0047] Although FIG. 6 shows the chute 102 as a component of the fresh concrete quality evaluation device 100, the component of the detection unit 104 may be provided in a detachable state on the chute 202 of the agitator vehicle.

[0048] Next, a method for evaluating the quality of fresh concrete using the quality evaluation device 100 will be described. In the method for evaluating the quality of fresh concrete according to this embodiment, concrete flowing out from the chute 202 of the agitator vehicle 200 is continuously poured into the chute 102 of the quality evaluation device 100, and the state (slump) of the fresh concrete flowing down the chute 102 is evaluated by the detection unit 104. Specifically, the sensor 108 detects the magnitude of elastic deformation occurring in the probe 106 as the fresh concrete flows down the chute 102.

[0049] Probe 106 is subjected to shear resistance and undergoes elastic deformation when it shears the fresh concrete flowing down chute 102. The shear resistance changes depending on the state (slump) of the fresh concrete, and accordingly the magnitude of elastic deformation of probe 106 changes. For example, if the fresh concrete is hard (low fluidity), the elastic deformation of probe 106 is large, and if the fresh concrete is soft (high fluidity), the elastic deformation of probe 106 is small.

[0050] The magnitude of the elastic deformation of the probe 106 is detected by the sensor 108 and output as an electrical signal. For example, if the sensor 108 is configured as a strain gauge, the strain on the strain gauge (deformation of the probe) is detected by a bridge circuit and output as an electrical signal. The output signal is recorded in a data logger or directly read and recorded by a computer. The condition (slump) of the fresh concrete is then evaluated based on the measured data.

[0051] From the data acquired from the sensor 108 (strain gauge), the load (shear resistance of the probe 106) due to the flowing fresh concrete is calculated using the following formula. P=εEbh 2 / (6L) where ε: dynamic strain of probe 3 (average over 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 the probe (200,000 N / mm 2 (Assuming b: Probe width (mm) h: Probe thickness (mm)

[0052] When the width of the first probe 106A is WA = 3 mm, the width of the second probe 106B is WB = 6 mm, the width of the third probe 106C is WC = 12 mm, and the width of the fourth probe 106D is WD = 24 mm, the shear resistance (Y axis, n = 10) is plotted against the width (X axis) of each probe 106. The intercept value (X = 0) of each sample is also shown in Table 1. [Table 1]

[0053] In the graph of FIG. 7, the horizontal axis represents the width of the probe 106, and the vertical axis represents the shear resistance of the probe. As is clear from the graph shown in FIG. 7 and Table 1, the results of 10 measurements show that there is little variance in the measured values. In addition, the intercept values ​​are in the range of 2.12 to 3.93, and the coefficient of variation of the intercept is 0.47 to 0.64. In this way, by using the quality evaluation device 100 according to this embodiment, the effect of obstructing the flow of fresh concrete does not affect other probes (flow obstructions), and the shear resistance of concrete can be evaluated with high accuracy.

[0054] After obtaining the average intercept at which each sample converges from the deformation amount (shear resistance) of the probe 106, the quality of the fresh concrete is determined by classifying it into one of a plurality of pre-labeled fresh concrete quality categories. The labeling may be, for example, three levels, or more. In this case, the finer the labeling, the more detailed the quality of the fresh concrete can be determined, but it is desirable to perform labeling appropriate to the application. In this embodiment, a lookup table is obtained in advance that directly associates the average intercept at which each sample converges with the label, and the label is determined using the lookup table.

[0055] As described above, the method for evaluating the quality of fresh concrete according to this embodiment can directly detect the state of the fresh concrete discharged from the drum of the agitator vehicle 200 and flowing out of the chute 202 using the detection unit 104, thereby enabling efficient quality evaluation of the fresh concrete.

[0056] According to the fresh concrete quality evaluation device 100 and the fresh concrete quality evaluation method using the same of this embodiment, the entire probe 106 placed in the chute 102 is buried in the flowing fresh concrete, thereby reducing the variability in the data detected by the sensor 108, improving measurement accuracy, and enabling highly reproducible evaluation.

[0057] Although the present invention has been described above with reference to the drawings, the present invention is not limited to the above-described embodiments and can be modified as appropriate without departing from the spirit of the present invention. For example, if a person skilled in the art appropriately adds, deletes, or modifies components based on the embodiments, such modifications are also included in the scope of the present invention as long as they incorporate the gist of the present invention. Furthermore, the above-described embodiments can be appropriately combined as long as there are no mutual contradictions, and technical matters common to the embodiments are included in each embodiment even if not explicitly stated.

[0058] Even if there are other effects and advantages different from those brought about by the aspects of each of the above-mentioned embodiments, those that are clear from the description in this specification or that 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]

[0059] 100: quality evaluation device, 102: chute, 104: detection unit, 106: probe, 106A: first probe, 106B: second probe, 106C: third probe, 106D: fourth probe, 107: support unit, 108: sensor, 108A: first sensor, 108B: second sensor, 108C: third sensor, 108D: fourth sensor, 110: support base, 200: agitator wheel, 202: chute, 210 hopper

Claims

1. A chute through which fresh concrete flows, a plurality of probes supported on a bottom surface of the chute and extending perpendicular to the bottom surface; sensors provided on the plurality of probes; The sensor measures the shear resistance generated in the probe. A quality evaluation device for fresh concrete characterized by the above.

2. The plurality of probes are arranged in a direction intersecting the direction in which the fresh concrete flows down in the chute. The device for evaluating the quality of fresh concrete according to claim 1.

3. The plurality of probes are arranged in a direction parallel to the direction in which the fresh concrete flows down in the chute. The device for evaluating the quality of fresh concrete according to claim 1.

4. The plurality of probes have different widths. The device for evaluating the quality of fresh concrete according to claim 2 or 3.

5. each of the plurality of probes having a different Young's modulus; The device for evaluating the quality of fresh concrete according to claim 2 or 3.

6. A support portion that supports the chute at a predetermined angle. The device for evaluating the quality of fresh concrete according to claim 1.

7. A plurality of probes extending upward from the bottom surface of a chute through which fresh concrete flows are used to measure the shear resistance generated in the probes when the fresh concrete flows down the chute; The slump value of the fresh concrete is evaluated from the measured value. A method for evaluating the quality of fresh concrete.

8. measuring shear resistance with the plurality of probes, and evaluating a slump value of the fresh concrete from the measured value; The method for evaluating the quality of fresh concrete according to claim 7.

9. Each of the plurality of probes is a cantilever beam having a rod-like or plate-like shape, and measures the shear resistance while being disposed perpendicular to the bottom surface of the chute. The method for evaluating the quality of fresh concrete according to claim 8.

10. the plurality of probes have different widths, and the values ​​of shear resistance measured for each of the different widths are plotted on a graph, and the intercept of a straight line drawn by the plot is extrapolated to determine the shear resistance; The method for evaluating the quality of fresh concrete according to claim 9.

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