JPH08152394A - Apparatus and method for deciding degree of cure of concrete - Google Patents

Abstract

PURPOSE: To judge the time of finishing concrete without depending plasterer's experience or intuition by directly and objectively grasping the state of the cure of the concrete. CONSTITUTION: An apparatus 1 for deciding the degree of the cue of concrete comprises a vibrating mechanism 4 having a mass 2 mounted at the upper end of a spring 3 stood on a base 5, an accelerometer 8 provided as vibration detecting means for detecting the vibration of the base 5, signal processing means 9 for processing the detection signal of the accelerometer 8, and a display unit 10 such as a liquid crystal display, etc., for displaying the output data of the means 9 in the base 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete hardening degree judging apparatus and method for judging the hardening degree of cast concrete.

[0002]

2. Description of the Related Art In concrete work, the top surface of concrete that does not contact the weir plate is rough-finished with a wooden iron, and if necessary, further smoothed with a metal iron. Since water accumulates on the surface, it is common to finish when the water disappears.

At the time when the setting of concrete begins, shrinkage cracks due to abrupt drying of the surface and sink cracks due to reinforcing bars are likely to occur. If such cracks occur, it is necessary to refinish with a trowel or the like. There is. It is said that the time for such refinishing is when the concrete has hardened so that it does not dent even when pressed with a finger.

Thus, when finishing concrete, it must be carefully determined in consideration of the state of hardening of concrete.

[0005]

On the other hand, the hardening rate of concrete varies considerably depending on the type of cement and admixture, temperature, curing method, etc., and in particular, various concretes such as high strength concrete and high fluidity concrete. Nowadays, the tendency is remarkable.

Therefore, when deciding when to finish concrete, it is often the case that the plasterer's experience and cans have to be relied upon, and thus the quality of the finished surface of concrete depends on the experience or ability of the plasterer. Was causing the problem.

In addition, at the jointing portion, before the next concrete is placed, it is necessary to remove the leitance generated on the surface by the breathing, but the leitance treatment is started even if the breathing is not completed. Occasionally, the start of the laitance treatment may be started too late and the surface may be hardened, which may require a great deal of labor to remove the laitance. Again, it has been desired to be able to accurately determine the state of hardening of concrete.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a concrete hardening degree judging device and method capable of objectively grasping the hardening state of concrete.

[0009]

In order to achieve the above object, the concrete hardening degree judging device of the present invention has a base part to which a vibration mechanism composed of a mass body and a spring is fixed, and the base part. And a vibration detecting means capable of detecting the vibration.

Further, the concrete hardening degree judging device of the present invention comprises a vibrating mechanism for vibrating the vibrating mechanism of claim 1.

Further, in the concrete hardening degree judging apparatus of the present invention, the vibrating mechanism of claim 2 is fixed to the base so that a predetermined reaction body faces the mass body, and the reaction body and the reaction body are provided. One of the mass bodies is an electromagnet, and the other is a magnet or a magnetic body.

Further, in addition to the second aspect, the concrete hardening degree judging device of the present invention further comprises a setting circuit capable of presetting a predetermined vibration value such as an amplitude and a damping rate when hardening the concrete, and the set value. A comparison circuit for comparing the output value of the vibration detecting means and a notification circuit for making a predetermined notification when the output value falls below the set value are provided.

Further, in addition to the fourth aspect, the concrete hardening degree judging device of the present invention further comprises a timing circuit for generating a control signal at a predetermined time interval until the output value falls below the set value, and the control signal. And a drive circuit for operating the vibrating mechanism in response to.

Further, in the concrete hardening degree judging apparatus of the present invention, the vibrating mechanism of claim 2 is fixed to the base so that a predetermined reaction body faces the mass body, and the reaction body and the reaction body are provided. One of the mass bodies is configured as an electromagnet and the other is configured as a magnet, and an alternating voltage is applied to the electromagnet so that the vibration mechanism can be steadily excited at a predetermined frequency.

Further, the concrete hardening degree judging device of the present invention is such that the projecting leg is attached to the concrete contact surface of the base of claim 1.

Further, according to the method for judging the degree of hardening of concrete of the present invention, as described in claim 8, a predetermined base is fixed near the surface of the concrete, and then the base is vibrated to detect the vibration of the base. Then, the degree of concrete hardening is determined by monitoring the detected vibration value or comparing the vibration value with preset values such as preset amplitude and damping rate.

[0017]

In the concrete hardening degree determining apparatus and method of the present invention, first, the base of the apparatus is fixed near the surface of the cast concrete, and then the vibration mechanism fixed to the base is vibrated.

To vibrate the vibrating mechanism, the mass body is subjected to a predetermined force, for example, it is pulled or pushed by a finger to give an initial displacement to the mass body, and then the above-mentioned force is released to freely vibrate the mass body. Just do it.

While the vibrating mechanism is vibrating, the base portion vibrates due to the vibrating action of the vibrating mechanism. Therefore, the vibration is detected by using a vibration detecting means such as an accelerometer. Then, the vibration of the vibrating mechanism and the vibration of the base portion are detected at predetermined time intervals to monitor changes in the amplitude and the damping rate.

As a result of the experiment, it was found that the amplitude of the base portion at each time was large at the time of placing concrete, but gradually decreased with the passage of time. This is because the concrete is still soft at the beginning of placing the concrete and does not restrain the movement of the base so much, so the base vibrates so as to be pushed into the concrete surface by the vibrating action of the vibration mechanism, It is considered that, as the time elapses, the cast concrete gradually hardens and restrains the movement of the base portion, so that the amplitude of the base portion gradually decreases, and almost no vibration occurs after the concrete is sufficiently hardened.

Therefore, the progress of hardening of concrete can be grasped by monitoring the changes in the amplitude and the attenuation rate detected at each time. Further, by comparing these vibration values with preset values, it is possible to determine the hardening time of the concrete.

If a vibrating mechanism for vibrating the vibrating mechanism described above is provided, the above-described operation of applying and releasing the initial displacement can be accurately performed. In particular, when the vibration mechanism is fixed to the base so that a predetermined reaction force body faces the mass body, and one of the reaction force body and the mass body is formed as an electromagnet and the other is formed as a magnet or a magnetic body. The vibration of the vibrating mechanism can be performed by a simple operation of energizing and disconnecting the electromagnet.

In addition to the above-mentioned vibration mechanism, a setting circuit capable of presetting a predetermined vibration value such as amplitude and damping rate during hardening of concrete, and the set value as an output value of the vibration detecting means. If a comparison circuit for comparing and a notification circuit that gives a predetermined notification when the output value falls below the set value, if the hardening of concrete has progressed to a predetermined degree, the notification circuit automatically It works and signals that the concrete has hardened.

Further, a timing circuit for generating a control signal at a predetermined time interval until the output value falls below the set value, and a drive circuit for operating the vibrating mechanism in response to the control signal are provided. In this case, the steps of vibration, vibration detection, and comparison are automatically repeated after the concrete is poured and until the concrete is hardened to a predetermined degree.

The above-mentioned vibration mechanism is fixed to the base so that a predetermined reaction body faces the mass body, and one of the reaction body and the mass body is an electromagnet and the other is a magnet. In addition, when an alternating voltage is applied to the electromagnet so that the vibration mechanism can be steadily excited at a predetermined frequency, by steadily exciting the vibration mechanism over a predetermined frequency range, The amplitude value of the base, ie the resonance curve, is obtained. Then, the progress of hardening of concrete can be grasped by comparing the resonance curves at each time and considering the changes in the resonance frequency, the amplitude at the resonance frequency, the damping constant, and the like.

Further, when the protruding leg is attached to the concrete contact surface of the base, the base is firmly fixed to the concrete surface.

[0027]

Embodiments of the concrete hardening degree determining apparatus and method of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) FIG. 1 is a schematic view showing a concrete hardening degree judging device 1 according to a first embodiment. As can be seen from the figure, in the concrete hardening degree determining apparatus 1 of the present embodiment, a mass body 2 is attached to the upper end of a spring 3 erected on a base portion 5 as a vibration mechanism 4, and the spring 3 is a mass body. 2 is a vibrating element having a restoring force proportional to the distance when it is displaced from the center position by a predetermined horizontal distance, and can take any form such as a plate shape and a bar shape.

The base 5 is formed, for example, in the shape of a box as shown in the figure, and the bottom of the base 5 contacting the concrete 6 has a protruding leg 7
It is good to attach.

The base portion 5 has an accelerometer 8 as a vibration detecting means for detecting the vibration of the base portion 5, a signal processing means 9 for processing a detection signal of the accelerometer 8, and output data of the signal processing means 9. And a display unit 10 such as a liquid crystal display for displaying.

The accelerometer 8 is arranged so that the horizontal acceleration component of the base 5 can be detected.

The signal processing means 9 amplifies the acceleration waveform of the base portion 5 detected by the accelerometer 8 by the amplifying circuit 11 and converts it into a velocity waveform by the built-in integrating circuit, and the high frequency component of the velocity waveform is filtered by the filter 12. After removing with A / D
The converter 13 converts the data into digital data, the arithmetic unit 14 processes the data, and outputs the processed data to the display unit 10.

It is preferable that the calculation unit 14 stores the amplitude data at each time in a memory so that the change in the amplitude data can be displayed on the display unit 10.

Concrete Hardness Determining Apparatus 1 of this Example
In (1), first, the device is installed on the surface of the cast concrete 6, and the vibrating mechanism 4 is vibrated.

In order to vibrate the vibrating mechanism 4, the mass body 2 is subjected to a predetermined force, for example, drawn or pushed by a finger to give an initial displacement to the mass body 2, and then the above-mentioned force is released to release the mass body 2. Can be freely vibrated.

While the vibrating mechanism 4 is vibrating, the base 5
Vibrates under the vibration of the vibration mechanism 4,
The vibration is detected by using the accelerometer 8. Then, the vibration of the vibrating mechanism 4 and the vibration of the base 5 are detected at predetermined time intervals to monitor changes in the amplitude and the damping rate.

FIG. 2 shows that the concrete hardening degree judging device 1 of this embodiment is allowed to stand still on the surface of the cast concrete, and the vibrating mechanism 4 is vibrated at a predetermined time interval. The experimental results detected at the time are shown, in which the horizontal axis shows the elapsed time (minutes) after concrete placement, and the vertical axis shows the vibration waveform voltage (mV) of the base 5.

As a result of the experiment, the amplitude of the base portion at each time is large at the time of placing concrete (300 to 40).
0 mV), it becomes smaller with the lapse of time, becomes less than 1/10 after 140 minutes, and gradually decreases thereafter.

This is because when the concrete is placed, the concrete is still soft and does not restrain the movement of the base portion 5 so much that the base portion 5 vibrates as shown in FIG. 3 (a).
While vibrating so as to be pushed into the surface of the concrete 6 by vibrating by the vibrating mechanism, the placed concrete gradually hardens and restrains the movement of the base portion 5 with the passage of time. It is considered that the amplitude of the base portion 5 gradually decreases as shown in FIG. 3 (b) despite the fact that the concrete is vibrating, and it hardly vibrates after the concrete is sufficiently hardened.

FIG. 4 shows the vibration waveform detected at each time point as a time history. (A) is the initial data when the concrete is placed, (b) is the data at an intermediate time, and (c) is
Is the data when the hardening of concrete has progressed considerably. As can be seen from these figures, at the beginning of concrete pouring, the amplitude is large and the damping rate is large, and the damping is immediate, but as the hardening of the concrete progresses, both the amplitude and the damping rate become smaller.

In this way, by monitoring the changes in the amplitude and the attenuation rate detected at each time, the progress of hardening of concrete can be grasped. Further, by comparing these vibration values with preset values, it is possible to determine the hardening time of the concrete.

As described above, according to the concrete hardening degree judging apparatus of this embodiment, the base part to which the vibration mechanism is attached is installed on the concrete surface immediately after the placing, and the vibration mechanism is vibrated, and the vibrating action is applied. By detecting the vibration component of the base with an accelerometer and monitoring the time variation of the amplitude and damping rate of the detected vibration, it becomes possible to directly grasp the hardening situation of the placed concrete, , Will be able to objectively judge the experience of the plasterer and the timing of finishing the concrete, which relied on the can.

In particular, recently, there are various concretes such as high-strength concrete and high-fluidity concrete that meet various needs. Therefore, it is necessary to have a considerable amount of experience and knowledge to accurately judge the timing of hardening of concrete. Although required, by using the concrete hardening degree determining apparatus of this embodiment, the hardening degree of concrete can be objectively grasped regardless of the type of cement or admixture.

Further, according to this embodiment, since the projecting leg is attached to the concrete contact surface of the base, the leg is
It can be embedded in hardening concrete to firmly fix the entire device and prevent the base from floating above the concrete surface.

The concrete hardening degree judging apparatus of the present embodiment can be applied to all situations in which the strength management of concrete after placing is important, for example, in the case of building work Removal, demolding form panel,
It can be applied when judging the time for terminating the curing of concrete in the cold.

In determining the timing of such a step, conventionally, the strength of the cast concrete is indirectly estimated by performing the compressive strength test of the specimen,
Although it was based on the guideline described in the building construction standard specification, the concrete hardening degree judging device of the present invention can directly evaluate the hardening degree of the placed concrete. Therefore, it is possible to make an objective judgment by excluding the subjectivity of the judge.

The timing of the relatance process has conventionally been confirmed only by touching it visually or actually with the operator, but by using the concrete hardening degree judging device according to the present invention, It is possible to judge the timing of the laitance treatment without being influenced by experience and ability.

In this embodiment, the output signal from the signal processing means is displayed on a predetermined display section. However, the output signal or the detected waveform from the accelerometer is taken out to the outside via a cable or the like, and this is output. After processing with a personal computer, etc., C
You may make it display on RT etc. and monitor concrete hardening degree. With such a configuration, it is possible to centrally monitor data at a large number of places at one place. In addition, the amplifier circuit, the filter, etc. may be omitted depending on the case.
Instead of the D converter, other means may be used, for example, a means for counting the number of waves until the set amplitude is reached after vibration.

Further, in the present embodiment, the spring of the vibration mechanism is a plate-shaped or rod-shaped spring, but instead of this, for example, a coil spring is arranged in the horizontal direction, and one end of the coil spring is at the base and the other end is at the other end. It may be fixed to the mass body to horizontally vibrate the mass body.

Further, in the present embodiment, the vibration direction is horizontal and the vibration component to be detected is horizontal. However, an accelerometer is arranged so that upper and lower components can be detected, and horizontal vibration is applied from the upper and lower components. The accompanying locking may be evaluated.

Further, a coiled spring is arranged in the vertical direction, the upper end of which is fixed to the top plate of the base and the lower end of which is fixed to the mass body so that the mass body is vertically vibrated and the vertical component of the base part is fixed. May be configured to be detected.

Further, in this embodiment, the projection-shaped legs are attached to the bottom surface of the base so that the bottom surface does not float above the concrete surface. However, by adjusting the ground contact pressure against the concrete surface, the base surface can be lifted. If it can be prevented, it is not necessary to make the leg projecting, and the leg itself may be omitted in some cases.

(Second Embodiment) Next, a concrete hardening degree determining apparatus according to a second embodiment will be described. Note that the same reference numerals are given to components and the like that are substantially the same as those in the above-described embodiment, and description thereof will be omitted.

FIG. 5 is a schematic view showing a concrete hardening degree judging device 21 according to the second embodiment. As can be seen in the figure, the concrete hardness determination device 21 of the present embodiment is
A coil spring 25 is suspended inside the base 5, and a mass body 26 made of a ferromagnetic material such as iron is provided at the lower end of the coil spring 25.
Is attached to form a vibration mechanism 27.

A cylindrical magnet 28 is attached near the center of the mass body 26.

Further, the concrete hardening degree judging device 21 of the present embodiment is provided with a hollow electromagnetic coil 24 as a vibrating mechanism for vibrating the vibrating mechanism 27 and a drive circuit 23 for driving this. The electromagnetic coil 24 has one end fixed to the bottom plate of the base 5 facing the mass body 26, and has a magnet 28.
The whole mass body 26 can be moved up and down in a state where it enters the hollow space, and it also acts as a reaction force body that attracts or repels the magnet 28 when energized, and the mass body 26 has a desired initial displacement. To be able to give.

The drive circuit 23 can apply a predetermined DC voltage to the electromagnetic coil 24.

Further, in the base 5, similarly to the concrete hardening degree judging device 1, an accelerometer 8 as a vibration detecting means for detecting the vibration of the base 5, and a signal processing means for processing a detection signal of the accelerometer 8. 9 and a display unit 10 such as a liquid crystal display for displaying output data of the signal processing means 9 are built in.

Concrete hardening degree judging device 2 of this embodiment
In No. 1, as shown in the flowchart of FIG. 6, first, the drive switch 22 is pushed to operate the drive circuit 23 to drive the electromagnetic coil 24 (step 101). Then, the electromagnetic coil 24 attracts or repels the magnet 28 to displace the mass body 26 by a predetermined amount. In this state, if the energization of the electromagnetic coil 24 is automatically cut off, the mass body 26 starts free vibration with the displacement amount as the initial displacement.

Next, the vibration of the base 5 is detected by the accelerometer 8 (step 102), and then the acceleration waveform of the base 5 detected by the accelerometer 8 is amplified by the amplifier circuit 11 and the built-in integrating circuit. Convert to velocity waveform (Step 10
3) After the high frequency component of the velocity waveform is removed by the filter 12 (step 104), it is converted into digital data by the A / D converter 13 (step 105), and this is processed by the calculation unit 14 and displayed on the display unit 10. Output.

Next, by looking at the display result on the display unit 10, the amplitude data at a predetermined time is compared with the vibration data at the time of placing (step 106), and the amplitude data at that time is determined with respect to the initial amplitude data. Is greater than or equal to
It is judged that the hardening of the concrete has not progressed yet and the concrete finishing time is too early, and after a predetermined time has passed, the electromagnetic coil is driven again and the above steps are repeated (step 107, NO).

On the other hand, when the amplitude data at that time becomes smaller than the original amplitude data by a predetermined ratio,
It is determined that the hardening of the concrete has progressed and it is time to finish the concrete (step 107, YES).

Since the present embodiment has the same effect as that of the first embodiment, the description thereof will be omitted. Particularly, in this embodiment, since the vibrating mechanism for vibrating the vibrating mechanism is provided, The operations of applying and releasing the initial displacement can be performed accurately and easily. Further, since the vibrating mechanism is formed by the electromagnetic coil as described above, the operation can be performed by a simple operation of energizing and disconnecting the electromagnet.

In this embodiment, the electromagnetic coil is used for the vibration mechanism. However, for example, the vibration mechanism is configured by appropriately combining mechanical elements such as a link, a locking claw and a lever, and the lever is pushed down. The initial displacement may be given and released.

Further, in the present embodiment, the reaction force body fixed to the base is an electromagnet and a part of the mass body is a magnet. However, the mass body is entirely made of a magnetic body, and the initial displacement is given only by suction. You may do it. Further, the reaction force body may be a permanent magnet and a part of the mass body may be an electromagnetic coil.

Further, similarly to the first embodiment, the output signal from the signal processing means or the detected waveform from the accelerometer is taken out to the outside via a cable or the like, processed by a personal computer or the like, and then displayed on a CRT or the like. You may make it monitor the concrete hardening degree. Further, the amplifier circuit, the filter and the like may be omitted in some cases, and other means, for example, a means for counting the number of waves until the set amplitude is reached after the vibration is applied may be used instead of the A / D converter.

(Third Embodiment) Next, a concrete hardening degree determining apparatus according to a third embodiment will be described. Note that the same reference numerals are given to components and the like that are substantially the same as those in the above-described embodiment, and description thereof will be omitted.

FIG. 7 is a schematic view showing a concrete hardening degree judging device 31 according to the third embodiment. As can be seen in the figure, in the concrete hardening degree judging device 31 of this embodiment as well as the concrete hardening degree judging device 21 described above, the vibration mechanism 27 is mounted in the base portion 5, and the vibration mechanism 2
Hollow electromagnetic coil 24 as a vibrating mechanism for vibrating 7.
And a drive circuit 23 for driving the same.

Further, the base portion 5 has a built-in accelerometer 8 as a vibration detecting means for detecting the vibration of the base portion 5 and a signal processing means 32 for processing a detection signal of the accelerometer 8.

The signal processing means 32 is different from the above-mentioned first or second embodiment in that the output data converted into digital data by the A / D converter 13 is read out from the setting circuit 34 in the comparison circuit 33. When the output data is higher than the set value, the timing circuit 35 generates a control signal for operating the drive circuit 23, while when the output data is lower than the set value. The notification circuit 36 is adapted to make a predetermined notification.

Here, the setting circuit 34 stores amplitude data as a set value when the degree of hardening of concrete is in a state suitable for finishing. Such a set value is preferably determined with reference to the result of an experiment in which the correspondence between the hardening state of concrete and the magnitude of the amplitude of the base is investigated.

Concrete hardening degree judging device 3 of this embodiment
In FIG. 1, as shown in the flow chart of FIG. 8, first, the drive switch 22 is pushed to make the drive circuit 23 operable, and in this state, the timing circuit 35
Then, a control signal is generated at predetermined time intervals (step 111), and the electromagnetic coil 24 is driven in response to the control signal (step 112).

Then, the electromagnetic coil 24 gives an initial displacement to the mass body 26 and releases the mass body 26 each time the control signal is received, thereby freely vibrating the vibrating mechanism 27.

Next, the vibration of the base 5 is detected by the accelerometer 8 (step 113), and then the acceleration waveform of the base 5 detected by the accelerometer 8 is amplified by the amplifier circuit 11 and the built-in integrating circuit. Convert to velocity waveform (Step 11
4) After the high frequency component of the velocity waveform is removed by the filter 12 (step 115), it is converted into digital data by the A / D converter 13 (step 116).

Next, the set value of the setting circuit 34, that is,
Amplitude data when the cast concrete is hardened to a state suitable for concrete finishing is compared with the output data digitally converted by the A / D converter 13 (step 117).

Next, when the output data exceeds the set value, the timing circuit 35 is continuously operated (step 118, NO), and the above steps are repeated.

On the other hand, when the output data is below the set value, the notification circuit 36 is operated to make a predetermined notification to notify that the concrete is in a state suitable for finishing (step 119). Although various means can be considered as the method of reporting, for example, an electronic buzzer built in the reporting circuit 36 is sounded, an LED also built in is made to emit light, or a command is sent to an externally connected PC for centralized monitoring. It is better to send In addition to the notification, the display unit 10 similar to that in the first or second embodiment may be provided in parallel so as to know the curing status during the process.

Since the present embodiment has the same effect as that of the second embodiment, its explanation will be omitted. However, particularly in the present embodiment, the set value for judging the hardening time of concrete is set in advance. After setting, compare the set value with the output data, and if the output data is larger than the set value and the hardening of the concrete has not progressed, the drive circuit is activated again after the elapse of a predetermined time to restart the vibration mechanism. If the output data becomes smaller than the set value and the concrete is at the time of finishing, it will be notified by the notification circuit, so the worker or monitor will
It is possible to accurately grasp the timing of concrete finishing.

In this embodiment, the vibration mechanism is automatically driven by providing the timing circuit, but this may be omitted in some cases.
In the case of such a configuration, the worker manually pushes the drive switch at predetermined time intervals, and each time, it is confirmed whether or not the notification circuit gives a notification that the time for finishing the concrete has come. If the time for finishing is not yet reached, make a notification to that effect in a form that can be distinguished from the above notification, for example, by changing the buzzer sound or changing the color of the indicator lamp. May be.

Further, in the above-mentioned embodiments, attention has been paid to how the magnitude of the amplitude changes, but the parameter for judging the degree of hardening of concrete is not limited to the amplitude of vibration. Instead of this or in addition to this, the damping rate of vibration at each time may be adopted. That is, a large amount of time history data as shown in FIG. 4 is collected from the time when the concrete is poured to the time when the concrete is hardened, and the degree of hardening of the concrete is determined based on the difference in the attenuation rate evaluated from such data. May be.

Although all the above-mentioned embodiments are configured to freely vibrate the vibrating mechanism, the vibrating mechanism is forcibly vibrated, that is, the driving circuits in the second and third embodiments are provided with an AC power source to cause electromagnetic vibration. Alternating voltage may be applied to the coil for a certain period of time, and the degree of hardening of the concrete may be determined by evaluating the vibration of the base portion during that time using the amplitude and damping rate as parameters.

In such a case, the vibration of the base becomes steady vibration, but in consideration of the frequency dependency in the dynamic interaction between the base and concrete, the vibration mechanism is forcibly excited in a predetermined frequency range, The vibration of the base in the frequency range should be evaluated in such a way as to obtain a resonance curve. In the case of such a configuration, the progress of hardening of concrete can be grasped by evaluating changes in the resonance frequency, the amplitude at the resonance frequency, the damping constant, etc. using the resonance curve.

Further, as in the first or second embodiment, the amplifier circuit, the filter, etc. may be omitted in some cases,
Instead of the A / D converter, other means may be used, for example, a means for counting the number of waves until the set amplitude is reached after vibration.

[0084]

As described above, the concrete hardening degree judging device of the present invention comprises the base portion to which the vibration mechanism composed of the mass body and the spring is fixed, and the vibration detecting means capable of detecting the vibration of the base portion. Therefore, it becomes possible to directly grasp the state of hardening of concrete, and it is possible to objectively judge the time for finishing concrete, which has conventionally relied on the experience of plasterers and cans.

Further, according to the method for judging the degree of hardening of concrete of the present invention, as described in claim 8, a predetermined base is fixed near the surface of the concrete, and then the base is vibrated to detect the vibration of the base. Then, the degree of concrete hardening is determined by monitoring the detected vibration value or comparing the vibration value with preset values of amplitude, damping rate, etc. It becomes possible to directly grasp the situation, and it is possible to objectively judge the time for finishing concrete, which has conventionally relied on the experience of plasterers and cans.

[0086]

[Brief description of drawings]

FIG. 1 is a schematic diagram of a concrete hardness determination device according to a first embodiment.

FIG. 2 is a graph showing experimental results.

FIG. 3 is an explanatory diagram showing an operation of the concrete hardening degree determining apparatus according to the present embodiment.

FIG. 4 is an explanatory view explaining the same operation.

FIG. 5 is a schematic diagram of a concrete hardness determination device according to a second embodiment.

FIG. 6 is a flowchart for explaining the operation of the concrete hardening degree determining apparatus of the second embodiment.

FIG. 7 is a schematic diagram of a concrete hardness determination device according to a third embodiment.

FIG. 8 is a flowchart for explaining the operation of the concrete hardening degree determining apparatus of the third embodiment.

[Explanation of symbols]

 1, 21, 31 Concrete hardening degree judging device 2, 26 Mass body 3, 25 Spring 4, 27 Vibration mechanism 5 Base 6 Concrete surface 7 Protruding leg 8 Accelerometer (vibration detecting means) 9, 32 Signal processing means 10 Display Part 23 Drive circuit 24 Electromagnetic coil (reaction body of vibration mechanism) 28 Magnet 33 Comparison circuit 34 Setting circuit 35 Timing circuit 36 Notification circuit

Continued Front Page (72) Inventor Jun Nakayama 3-8-15 Chitosedai, Setagaya-ku, Tokyo

Claims (8)

[Claims] 1. A concrete hardening degree judging device comprising: a base portion to which a vibration mechanism composed of a mass body and a spring is fixed; and a vibration detecting means capable of detecting the vibration of the base portion. 2. The concrete hardening degree judging device according to claim 1, further comprising a vibrating mechanism for vibrating the vibrating mechanism. 3. The vibrating mechanism fixes a predetermined reaction body to the base so as to face the mass body, one of the reaction body and the mass body is an electromagnet, and the other is a magnet or a magnetic body. The concrete hardening degree determination device according to claim 2, which is configured as follows. 4. A setting circuit capable of presetting a predetermined vibration value such as an amplitude and a damping rate during hardening of concrete, a comparison circuit for comparing the set value with an output value of the vibration detecting means, and the output value. The concrete hardening degree determination device according to claim 2, further comprising a notification circuit that issues a predetermined notification when the value is below the set value. 5. A timing circuit for generating a control signal at a predetermined time interval until the output value falls below the set value,
The concrete hardening degree determination device according to claim 4, further comprising a drive circuit that operates the vibration mechanism in response to the control signal. 6. The vibrating mechanism is configured such that a predetermined reaction body is fixed to the base so as to face the mass body, and one of the reaction body and the mass body is an electromagnet and the other is a magnet. At the same time, the concrete hardening degree determining device according to claim 2, wherein an alternating voltage is applied to the electromagnet so that the vibrating mechanism can be steadily excited at a predetermined frequency. 7. The concrete hardening degree determining device according to claim 1, wherein a protruding leg is attached to the concrete contact surface of the base portion. 8. A predetermined base is fixed near the surface of concrete, then the base is vibrated to detect the vibration of the base, and then the detected vibration value is monitored or the vibration value is measured. A concrete hardening degree judging method characterized by judging the degree of concrete hardening by comparing preset values such as amplitude and damping rate.