JP5715040B2 - Method and apparatus for testing fresh concrete - Google Patents

Description

  The present invention affects the quality and workability of concrete, such as the consistency (resistance to deformation and flow) of fresh concrete of concrete agitator cars and the presence or absence of material separation (separation of coarse aggregate and mortar content of concrete). The present invention relates to a test method and apparatus for fresh concrete that automatically inspects the properties to be performed at the time of unloading and prevents construction defects and quality accidents.

Usually, the consistency of fresh concrete is evaluated by the slump test (JIS
A 1101) and slump flow test (JIS A 1150) values are representative, and if it is within a predetermined range, it is judged to be acceptable.

Implementation frequency of these tests, in general has become a case that once the basic, also quality change in the hammering was observed for each implantation Engineering each per-implantation day-ku, and 150m ³ or fraction thereof (Japanese Architecture (Academic Society Building Standard Specification / Explanation JASS5 Reinforced Concrete Work). For high-fluidity concrete, which is a special concrete, `` Gap passage test method using high-fluidity concrete filling device (draft) '' (JSCEF511) and `` L-flow test method for high-fluidity concrete (draft) '' ( Test methods such as JSCE-F514) have been established.

  Conventionally, concrete produced in a ready-mixed concrete production plant is partly collected in the plant factory and subjected to slump tests, etc. to manage properties such as consistency and material separation resistance. It is confirmed whether it conforms to the target properties such as consistency and material separation resistance set for each site.

  However, when transporting concrete to the placement site, the hydration reaction progresses over time and the slump value gradually decreases, and the property values such as consistency and material separation resistance also decrease accordingly. Therefore, for example, if the transportation time by the agitator vehicle is long, the properties that were suitable at the time of shipment may not be suitable at the time of placement on site.

On the other hand, in order to evaluate the consistency and material separation of concrete, a technique for installing and monitoring a camera in the drum of an agitator car is also proposed in the following patent document.
JP 2006-159658 A JP 2009-852 A

  Patent Document 1 provides a concrete quality control device for an agitator vehicle capable of managing properties such as consistency and material separation resistance of a plurality of agitator vehicles in real time in a management office. The agitator vehicle includes a television camera that photographs the movement and adhesion of concrete in the mixer drum, and a transmission terminal that transmits the concrete management information including the image data to the server of the management office.

  In addition, the server of the management office includes a receiving terminal that receives concrete management information transmitted from a plurality of agitator vehicles, and a monitor that displays the concrete management information.

  The television camera is provided as an imaging means for photographing the inside of the mixer drum at an upper part of a charging hopper for charging concrete into the mixer drum, and rolls in the rotating mixer drum by the operation of the television camera. It is possible to always photograph the movement of concrete to be performed and the degree of adhesion to the inner wall of the mixer drum 2.

  Then, the manager of the management office looks at the concrete management information such as the photographed image displayed on the monitor, and determines whether the properties of each agitator vehicle such as the consistency and material separation resistance match the target properties. judge.

  In Patent Document 2, the property of ready-mixed concrete agitated in the drum of the agitator car is positioned on a horizontal plane perpendicular to the vertical direction at the opening of the drum of the agitator car, and the drum enters the drum. A laser marking device that emits laser light and an imaging device that captures an image in the drum are provided, and the imaging device captures the laser light and the surface of the ready-mixed concrete in the drum.

  In this case, since the imaging device captures the laser beam and the surface of the ready-mixed concrete in the drum, the reference line can be represented in the captured image. That is, since the laser marking device is positioned on the horizontal plane, accurate horizontal and vertical lines can be represented in the image.

  In addition, when the drum is rotating, the surface of the ready-mixed concrete has a certain angle with respect to the horizontal line due to its properties. Since an accurate horizontal line or vertical line can be represented in the photographed image, the angle formed between the surface of the ready-mixed concrete and the horizontal line can be easily obtained by displaying the image on a display device.

  Further, when the drum is rotating, the shape of the surface of the ready-mixed concrete (for example, the height or depth of the unevenness) also changes according to the property. Since an accurate horizontal line or vertical line can be represented in the captured image, the shape of the surface of the ready-mixed concrete can be easily grasped by displaying the image on a display device. Thereby, it becomes possible to specify the consistency of ready-mixed concrete.

  The consistency of fresh concrete substitutes the result of the slump (flow) test. Conventionally, however, it takes time and labor to separately collect a test sample from an agitator vehicle and perform the test manually.

  During the test, the unloading of concrete from the agitator vehicle will be interrupted, which will affect the progress of the construction. Therefore, the test must be limited to the frequency described in “Prior Art”, and the concrete of the agitator car other than the test object is directly placed using a concrete pump car, etc., resulting in pump clogging or poor construction. There is a case to do.

  Furthermore, the material separation is only confirmed qualitatively by visual observation during the above-described slump (flow) test, and there is a problem that individual differences occur in the evaluation.

  As described in Patent Documents 1 and 2, in order to evaluate the consistency and material separation of concrete, the method of installing and monitoring a camera in the drum of an agitator vehicle requires manpower for monitoring, and individual agitator vehicles A camera must be installed in the camera, which is not realistic from the viewpoint of introduction cost.

  The object of the present invention is to eliminate the inconvenience of the above-mentioned conventional example, and by measuring the flow velocity and volume of the concrete flowing through the chute automatically and non-contacting using an image, it is possible to easily test all agitator vehicles, In addition, since the degree of material separation can be quantitatively evaluated by image processing, it is possible to provide a test method and apparatus for fresh concrete that is unlikely to cause individual differences in evaluation unlike the case of qualitative confirmation by visual observation. It is in.

  In order to achieve the above object, the present invention, as a method for testing fresh concrete, uses a camera attached to a chute of an agitator car to photograph a concrete surface flowing through the chute at regular intervals, and at the same time, a cross section of concrete at a certain position. Measure the shape and the slope of the chute, calculate the concrete flow velocity from the measured photograph, calculate the concrete cross-sectional area from the cross-sectional shape, then calculate the flow rate per unit time from the concrete flow velocity and cross-sectional area, Finally, the gist is to compare the calculated flow rate with the standard flow rate determined for each inclination of the chute, and to judge that the flow rate is acceptable if the standard flow rate is within an allowable range.

  In addition, as a fresh concrete test apparatus, the present invention firstly, a camera for photographing the concrete surface flowing through the chute at regular intervals, a planar laser distance meter for measuring the height of the concrete surface in the chute, Processes data from inclinometers that measure the inclination of the chute, these cameras, flat laser distance meters, and inclinometers, and calculates the flow rate per unit time from the flow velocity and cross-sectional area of the concrete flowing through the chute. And a computer that displays a result of the determination, secondly, comparing the measured flow rate with a standard flow rate determined for each inclination of the chute, determining whether the standard flow rate is within an acceptable range, The camera, the flat laser distance meter and the inclinometer are provided on the shading cover placed on the chute, and the light is attached to this shading cover. It is intended to.

  According to the first and second aspects of the present invention, before unloading the concrete from the agitator vehicle, the apparatus of the present invention is attached to the chute, the flow velocity of the concrete flowing through the chute is processed by image processing, and the volume is measured by a laser rangefinder. The image measured and used for measuring the flow velocity is simultaneously used for determining the degree of material separation. In this way, it is possible to test all agitator vehicles by automatically and non-contacting the flow velocity and volume of the concrete flowing through the chute using images, and quantitatively evaluate the degree of material separation by image processing. can do.

  According to the third aspect of the present invention, the apparatus of the present invention can be set simply by placing the light shielding cover on the chute without taking up space. Inclinometer positioning can be performed correctly, and an optical environment for camera photography can be created.

  As described above, the method and apparatus for testing fresh concrete according to the present invention can easily test all agitator vehicles by automatically and non-contactly measuring the flow velocity and volume of concrete flowing through a chute using an image. In addition, since the degree of material separation can be quantitatively evaluated by image processing, unlike individual qualitative confirmation by visual observation, there is no possibility of individual differences in evaluation.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of a test method and apparatus for fresh concrete according to the present invention. In the figure, reference numeral 6 denotes a chute for unloading concrete from an agitator vehicle.

  First, the fresh concrete test apparatus of the present invention will be described. In the figure, 5 is a light shielding cover, which is a rectangular box with an opening on the bottom surface, which is installed on the chute 6, and has a step difference between the left and right sides. It is hooked on the edge of the chute 6 at this stepped portion. A camera 1, a flat laser distance meter 2, and an inclinometer 3 were attached to the light shielding cover 5.

  The camera 1 captures the flow of concrete in the chute 6.

  The planar laser distance meter 2 measures the height of the concrete surface in the chute 6.

  The inclinometer measures the inclination of the chute 6.

  The camera 1, the flat laser distance meter 2, and the inclinometer 3 can be positioned by being attached to the light shielding cover 5, and can block outside light. The light shielding cover 5 is provided with illumination 4 to provide a light environment for camera photography.

  In the figure, reference numeral 7 denotes a computer which receives data from the camera 1, the flat laser distance meter 2, and the inclinometer 3, and processes this data to determine pass / fail. Further, the determination result is displayed.

  As described above, the apparatus of the present invention includes the camera 1 that photographs the concrete surface flowing through the chute 6 at regular intervals, the planar laser distance meter 2 that measures the height of the concrete surface in the chute 6, and the inclination of the chute 6. Process the data from the inclinometer 3, these cameras 1, the flat laser distance meter 2, and the inclinometer 3, and calculate the flow rate per unit time from the flow velocity and cross-sectional area of the concrete flowing through the chute 6. The computer 7 compares the calculated flow rate with the standard flow rate determined for each inclination of the chute, determines whether it is acceptable if the standard flow rate is within the allowable range, and determines whether or not it is acceptable, and displays the determination result.

  Next, the method for testing fresh concrete of the present invention performed using the apparatus of the present invention will be described. FIG. 5 is a flowchart showing the determination procedure. First, using the apparatus, a concrete surface flowing through the chute 6 is photographed at regular intervals using the camera 1 attached to the chute of the agitator vehicle. [Step (I)]

  At the same time, the cross-sectional shape of the concrete at a certain position and the inclination of the chute 6 are measured. [Step (b) (c)]

  The flow velocity of the concrete is calculated from the measured photograph, and the cross-sectional area of the concrete is calculated from the cross-sectional shape. [Step (d) (e)]

  Next, the flow rate per unit time is calculated from the flow velocity and cross-sectional area of the concrete. [Step]

  Finally, the calculated flow rate is compared with the standard flow rate determined for each inclination of the chute, and if it is within the allowable range of the standard flow rate, it is determined that it is acceptable. [Step (G) (Chi) (Re)]

  Thus, the present invention attaches the device of the present invention to the chute 6 before unloading the concrete from the agitator vehicle, measures the flow velocity of the concrete flowing through the chute 6 by image processing, and measures the volume by the laser distance meter 2. The image used to measure the flow velocity is simultaneously used to determine the degree of material separation.

  Previous studies have revealed that there is a strong correlation between concrete flow velocity and consistency. (Sakura et al .: Experiments on fluidity evaluation of fresh concrete using inclined flow tester, Summary of Annual Conference of Architectural Institute of Japan, pp.591-592, 2010.9)

  The calculation method of the flow velocity of the concrete is as follows. FIG. 7 shows a calculation procedure. As shown in FIG. 6, images of time mt and time (m + 1) t are taken using the camera 1 installed on the concrete surface. [Step (A): The distance per pixel of the image of the camera with respect to the height from the concrete surface to the camera is calculated. Step (b): Images are continuously captured n times every hour (t). ]

  Next, the common point of the two captured images is determined, and the difference in vector distance of the common point position between the mt image and the (m + 1) t image is calculated. [Step (c): A common point between the images of time mt and (m + 1) t is determined (from m = 1 to n). ]

  The calculated vector distance is set as the moving distance of the concrete from time mt to time (m + 1) t, and the concrete speed is calculated using the photographing interval and the moving distance. [Step (d): The pixel difference between the common points of the images at time mt and (m + 1) t is calculated. Step (e): The movement distance is calculated from the calculated pixels. Step (f): The speed (nm / t) of the concrete is calculated using the moving distance and time. ]

  The calculation procedure of the cross-sectional area of concrete is shown in FIG. A two-dimensional planar laser rangefinder 2 (for example, Hokuyo Electric UBG · 04LX · F01) is installed so as to be perpendicular to the surface of the chute 6 and the distance to the chute surface is measured. [Step (I)]

Next, when the concrete flows through the chute 6, the distance to the concrete surface is measured [Step (b): The distance to the concrete surface is measured m times at each time t], and the distance to the chute surface and the concrete surface are measured. The cross-sectional area of the concrete is calculated from the difference in distance. [Step (c): Using the distance between the chute surface and the concrete surface, the concrete cross-sectional area (mm ² ) is calculated at each time t. ]

The method for calculating the flow rate of concrete is to obtain the flow rate s of concrete using Equation 1 from the flow velocity v and the cross-sectional area r of the concrete at the calculated time t.
s = v × r Equation 1

  As shown in FIG. 10, a standard flow rate for each type of concrete is created, and the calculated flow rate is compared with the standard flow rate determined for each slope of the chute. Judge that it is a pass. This determination result is displayed on the computer 7.

1 is a perspective view showing an embodiment of a test method and apparatus for fresh concrete according to the present invention. It is a side view which shows one Embodiment of the testing apparatus of the fresh concrete of this invention. It is a vertical side view which shows one Embodiment of the testing apparatus of the fresh concrete of this invention. It is a vertical front view which shows one Embodiment of the testing apparatus of the fresh concrete of this invention. It is a flowchart which shows the procedure of the determination of the test method of the fresh concrete of this invention. It is explanatory drawing which shows the imaging | photography method of concrete. It is a flowchart which shows the calculation procedure of the flow velocity of the concrete of the test method of the fresh concrete of this invention. It is explanatory drawing which shows the calculation method of the cross-sectional area of concrete. It is a flowchart which shows the calculation procedure of the cross-sectional area of concrete. It is an image figure of the standard flow volume in pass / fail judgment.

DESCRIPTION OF SYMBOLS 1 ... Camera 2 ... Plane laser distance meter 3 ... Inclinometer 4 ... Illumination 5 ... Shading cover 6 ... Chute 7 ... Computer

Claims (3)

Using a camera attached to the chute of the agitator car, the concrete surface flowing through the chute is photographed at regular intervals.
At the same time, measure the cross-sectional shape of the concrete at a certain position and the inclination of the chute,
Calculate the flow velocity of the concrete from the measured photograph, calculate the cross-sectional area of the concrete from the cross-sectional shape,
Next, the flow rate per unit time is calculated from the flow velocity and cross-sectional area of the concrete,
Finally, the calculated flow rate is compared with a standard flow rate determined for each inclination of the chute, and if it is within the allowable range of the standard flow rate, the fresh concrete test method is characterized. A camera that shoots the concrete surface flowing through the chute at regular intervals;
A planar laser rangefinder that measures the height of the concrete surface in the chute;
An inclinometer to measure the inclination of the chute,
Process data from these cameras, flat laser rangefinders, and inclinometers,
The flow rate per unit time is calculated from the flow velocity and cross-sectional area of the concrete flowing through the chute, and the calculated flow rate is compared with the standard flow rate determined for each slope of the chute. A test apparatus for fresh concrete, comprising: a computer for determining whether to pass or not and displaying the determination result.   3. The fresh concrete testing apparatus according to claim 2, wherein the camera, the flat laser distance meter, and the inclinometer are provided on a light shielding cover placed on a chute, and illumination is attached to the light shielding cover.

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