JP3144454B2 - Apparatus and method for determining degree of concrete hardening - Google Patents

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 upper surface of concrete not in contact with a weir plate is rough-finished with a wooden iron, and if necessary, is further smoothed with a metal iron. Since water collects on the surface, finishing is generally performed in anticipation of the disappearance of water.

[0003] Further, at the time when concrete starts to set, shrinkage cracks due to rapid drying of the surface and settlement cracks due to reinforcing steel are liable to occur. When such cracks occur, refining with a trowel or the like is necessary. There is. It is said that the time of such refinishing is when the concrete upper surface has hardened so as not to be dented even when pressed with a finger.

As described above, when finishing concrete, it must be carefully determined in consideration of the condition of hardening of the concrete.

[0005]

On the other hand, the curing speed of concrete varies depending on the type of cement and admixture, the temperature, the curing method, and the like. In particular, various concretes such as high-strength concrete and high-fluid concrete are available. These days, the trend is remarkable.

[0006] Therefore, in determining the timing of finishing concrete, it is often necessary to rely on plasterers 'experiences and cans, and thus the quality of the concrete finishing surface depends on the plasterers' experience or ability. The problem had arisen.

[0007] In addition, at the joint, it is necessary to remove the latence generated on the surface by the breathing before casting the next concrete. In some cases, the start of the latence treatment is too slow and the hardening of the surface progresses, so that the removal of the latence requires a great deal of labor. In this case, too, it has been desired to be able to accurately judge the state of hardening of the concrete.

The present invention has been made in consideration of the above circumstances, and has as its object to provide a concrete hardening degree judging apparatus and method capable of objectively grasping the hardening state of concrete.

[0009]

In order to achieve the above object, a concrete hardening degree judging device according to the present invention comprises, as described in claim 1, a base to which a vibration mechanism comprising a mass body and a spring is fixed; Vibration detection means capable of detecting the vibration of the, the vibration mechanism, one end of the spring
The other end is attached to the base body and the mass body, respectively .

The concrete hardening degree judging device of the present invention is provided with a vibrating mechanism for vibrating the vibrating mechanism of the first aspect.

Further, according to the concrete hardening degree judging device of the present invention, the vibration mechanism according to claim 2 is fixed to the base so that a predetermined reaction body is opposed to the mass body, One of the mass bodies is configured as an electromagnet, and the other is configured as 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 the concrete is hardened, and A comparison circuit for comparing with an output value of the vibration detecting means; and a notification circuit for performing a predetermined notification when the output value is lower than the set value.

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 predetermined time intervals until the output value falls below the set value, And a drive circuit for operating the vibration mechanism in response to the

According to a second aspect of the present invention, there is provided an apparatus for judging the degree of hardening of a concrete, wherein the vibration mechanism according to claim 2 is fixed to the base such that a predetermined reaction body is opposed to the mass body. One of the mass bodies is configured as an electromagnet, and the other is configured as a magnet, and an AC voltage is applied to the electromagnet so that the vibration mechanism can be vibrated at a predetermined frequency.

Further, in the concrete hardening degree judging device according to the present invention, a projecting leg is attached to the concrete contact surface of the base of the first aspect.

Further, according to the eighth aspect of the present invention, there is provided a method for determining the degree of hardening of concrete , wherein one end of a spring is connected to a base,
A vibration mechanism with the other end attached to the mass body is fixed.
The base is fixed to the vicinity of the surface of the concrete, and then the base is vibrated to detect the vibration of the base. Then, the detected vibration value is monitored or the vibration value is set to a predetermined amplitude. , The degree of concrete hardening is determined by comparing with the set values of the damping rate and the like.

[0017]

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

In order to vibrate the vibration mechanism, a predetermined force, for example, a finger is pulled or pushed with a finger to give an initial displacement to the mass body, and then the mass body is freely vibrated by releasing the above-mentioned force. Just do it.

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

As a result of the experiment, it was found that the amplitude of the base at each time was large at the beginning of the concrete casting but gradually decreased with time. This is because when the concrete is cast, the concrete is still soft and does not restrict the movement of the base much, so the base vibrates as it is pushed into the concrete surface by the vibration action by the vibration mechanism, It is considered that the concrete poured gradually hardens over time and restricts the movement of the base, so that the amplitude of the base gradually decreases and hardly vibrates after the concrete has sufficiently hardened.

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

Here, when a vibration mechanism for vibrating the above-described vibration mechanism is provided, the above-described operation of giving and releasing the initial displacement can be performed accurately. In particular, when the vibration mechanism is configured such that a predetermined reaction body is fixed to the base so as to face the mass body, one of the reaction body and the mass body is configured as an electromagnet, and the other is configured as a magnet or a magnetic body. In addition, the vibration of the vibration mechanism can be performed by a simple operation of energizing and shutting off the electromagnet.

Further, in addition to the above-mentioned vibration mechanism, a setting circuit capable of setting in advance a predetermined vibration value such as an amplitude and a damping rate at the time of concrete hardening, and setting the setting value to an output value of the vibration detecting means. When a comparison circuit for comparing and a notification circuit for performing a predetermined notification when the output value is lower than the set value are provided, if the concrete hardening has progressed to a predetermined degree, the notification circuit is automatically set. Operates to signal that the concrete has hardened.

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

Further, the above-mentioned vibration mechanism is configured such that a predetermined reaction body is fixed to the base so as to face the mass body, one of the reaction body and the mass body is constituted by an electromagnet, and the other is constituted by a magnet. In addition, when an AC voltage is applied to the electromagnet and the vibration mechanism is configured to be able to steadily vibrate at a predetermined frequency, by oscillating the vibration mechanism steadily over a predetermined frequency range, An amplitude value of the base, that is, a resonance curve is obtained. By comparing the resonance curves at each time point and considering changes in the resonance frequency, the amplitude at the resonance frequency, the attenuation constant, and the like, it is possible to grasp the progress of concrete hardening.

When a protruding leg is attached to the concrete contact surface of the base, the base is firmly fixed to the concrete surface.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the apparatus and method for determining the degree of hardening of concrete 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, the concrete hardening degree judging device 1 of the present embodiment has a vibrating mechanism 4 in which a mass body 2 is attached to an upper end of a spring 3 erected on a base 5, and the spring 3 is Reference numeral 2 denotes a vibrating element having a restoring force proportional to the distance when displaced from the center position by a predetermined horizontal distance, and may have any shape such as a plate shape or a rod shape.

The base 5 is formed, for example, in the shape of a box as shown in the figure, and has protruding legs 7
It is better to attach.

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

The accelerometer 8 is provided 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 5 detected by the accelerometer 8 by the amplifier circuit 11 and converts it into a speed waveform by a built-in integrating circuit. A / D after removing with
The data is converted into digital data by the converter 13, processed by the arithmetic unit 14, and output to the display unit 10.

The arithmetic section 14 preferably stores the amplitude data at each time in a memory so that a change in the amplitude data can be displayed on the display section 10.

The concrete hardening degree judging device 1 of this embodiment
First, the device is installed on the surface of the cast concrete 6 and the vibration mechanism 4 is vibrated.

In order to vibrate the vibration mechanism 4, the mass body 2 is given a predetermined force, for example, an initial displacement is applied to the mass body 2 by pulling or pushing it with a finger, and then the above-mentioned force is released to release the mass body 2. Can be freely vibrated.

While the vibration mechanism 4 is vibrating, the base 5
Is vibrated by the vibration effect of the vibration mechanism 4,
The vibration is detected using the accelerometer 8. Then, the vibration of the vibration mechanism 4 and the detection of the vibration of the base 5 are performed at predetermined time intervals, and changes in the amplitude and the attenuation rate are monitored.

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 vibration mechanism 4 is vibrated at predetermined time intervals. The results of the experiment detected at the time are shown, in which the horizontal axis represents the elapsed time (minutes) after the concrete was poured, and the vertical axis represents the vibration waveform voltage (mV) of the base 5.

As a result of the experiment, the amplitude of the base at each time was large at the beginning of concrete placement (300 to 40).
0 mV), it becomes smaller with the passage of time, becomes 1/10 or less after about 140 minutes, and gradually decreases thereafter.

This is because the concrete is still soft at the beginning when the concrete is cast and does not significantly restrict the movement of the base 5, so that the base 5 is moved by the vibration mechanism 4 as shown in FIG.
Vibrates so as to be pushed into the surface of the concrete 6 by the vibrating action of the concrete 6, while the concrete poured in hardens gradually over time and restrains the movement of the base 5. It is considered that the amplitude of the base 5 gradually decreases as shown in FIG. 3 (b) even though the concrete is vibrating, and hardly vibrates after the concrete is sufficiently hardened.

FIGS. 4A and 4B show the vibration waveforms detected at each time as time histories, wherein FIG. 4A shows the data at the time of placing concrete, FIG. 4B shows the data at the intermediate time, and FIG.
Is the data when the concrete hardened considerably. As can be seen from these figures, at the beginning of concrete placement, the amplitude is large and the damping rate is large, and the damping rate is reduced immediately. However, as the concrete hardens, the amplitude and the damping rate are reduced.

As described above, by monitoring changes in the amplitude and the attenuation rate detected at each time, the progress of concrete hardening can be grasped. Also, 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 device of the present embodiment, the base having the vibration mechanism attached thereto is mounted on the concrete surface immediately after casting, and the vibration mechanism is vibrated, and the vibrating action is applied to the vibration mechanism. Since the base vibration component is detected by an accelerometer and the time variation of the detected vibration amplitude and damping rate is monitored, it is possible to directly grasp the hardening condition of the concrete poured in. It will be possible to objectively judge when to finish concrete, which relied on plasterers' experiences and cans.

In particular, recently, there are a variety of concretes that meet various needs such as high-strength concrete and high-fluidity concrete. Therefore, it is a considerable experience and knowledge to accurately determine the time of hardening of concrete. Although required, the degree of concrete hardening can be objectively grasped by using the concrete hardening degree determination device of the present embodiment regardless of the type of cement or admixture.

Further, according to this embodiment, since the projecting legs are attached to the concrete contact surface of the base, the legs are
It is embedded in the hardening concrete and firmly secures the entire device, preventing the base from rising from the concrete surface.

The apparatus for judging the degree of concrete hardening according to the present embodiment can be applied to all situations where the management of the strength of concrete after casting is important. Removal, removal of formwork panels,
The present invention can be applied when judging the timing of curing of concrete in the cold and the like.

In judging the timing of such a process, conventionally, the strength of cast concrete is indirectly estimated by performing a compressive strength test on a specimen,
Although it was based on the guideline described in the standard specification of building construction, the degree of hardening of the poured concrete can be directly evaluated by using the concrete hardening degree judging device of the present invention. Therefore, it is possible to make an objective judgment without the subjectivity of the person making the judgment.

In the past, the timing of the latency processing had to be checked by the operator with his or her eyes or by actually touching it. However, by using the concrete hardening degree judging device according to the present invention, the timing of the worker can be confirmed. The timing of latency processing can be determined without being influenced by experience or ability.

In this embodiment, the output signal from the signal processing means is displayed on a predetermined display unit. However, the output signal or the detected waveform from the accelerometer is taken out via a cable or the like, and this is taken out. After processing on PC etc., C
It may be displayed on an RT or the like to monitor the degree of concrete hardening. With such a configuration, data at multiple locations can be centrally monitored at one location. Further, an amplifier circuit, a filter, and the like may be omitted in some cases.
Instead of the D converter, other means, for example, means for counting the number of waves until the set amplitude is reached after the vibration may be used.

In this embodiment, the spring of the vibration mechanism is a plate-shaped or rod-shaped spring. Instead, for example, a coil spring is arranged in the horizontal direction, and one end of the coil spring is used as a base and the other end is used. The mass body may be horizontally vibrated while being fixed to the mass body.

In this embodiment, the vibration direction is set to the horizontal direction, and the vibration component to be detected is set to the horizontal component. However, an accelerometer is arranged so that the vertical component can be detected. The resulting locking may be evaluated.

Further, a coil-shaped spring is disposed 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. May be configured to be detected.

Further, in this embodiment, the protruding legs are attached to the bottom surface of the base so that the bottom surface does not rise from the concrete surface. However, the lifting of the base portion is adjusted by adjusting the contact pressure against the concrete surface. If it can be prevented, the leg need not be formed in a projecting shape, and the leg itself may be omitted in some cases.

(Second Embodiment) Next, a concrete hardening degree judging device 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 a second embodiment. As can be seen from the figure, the concrete hardening degree judging device 21 of the present embodiment
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 a lower end of the coil spring 25.
To form a vibration mechanism 27.

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

The concrete hardening degree judging device 21 of this embodiment includes a hollow electromagnetic coil 24 as a vibration mechanism for vibrating the vibration mechanism 27 and a drive circuit 23 for driving the same. The electromagnetic coil 24 has one end fixed on a bottom plate of the base 5 facing the mass body 26 and a magnet 28
Is capable of moving up and down as a whole while the mass body 26 is in the hollow space, and acts as a reaction force body that attracts or repels the magnet 28 when energized, and causes the mass body 26 to have a desired initial displacement. Can be given.

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

As in the concrete hardening degree determination device 1, the base 5 has an accelerometer 8 as vibration detecting means for detecting 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.

The concrete hardening degree judging device 2 of the present embodiment
In step 1, as shown in the flowchart of FIG. 6, first, the drive switch 22 is pressed to activate the drive circuit 23 to drive the electromagnetic coil 24 (step 101). Then, the electromagnetic coil 24 draws 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 an initial displacement.

Next, the vibration of the base 5 is detected by the accelerometer 8 (step 102). Then, the acceleration waveform of the base 5 detected by the accelerometer 8 is amplified by the amplifier circuit 11 and the built-in integration 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), the data is converted into digital data by the A / D converter 13 (step 105). Output.

Next, looking at the display result of the display unit 10, the amplitude data at a predetermined time is compared with the vibration data at the time of the initial driving (step 106). Is greater than or equal to
It is determined that the concrete has not yet hardened and the concrete finishing time is too early, and after a predetermined time has elapsed, the electromagnetic coil is driven again to repeat the above steps (step 107, NO).

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

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

In the present embodiment, an electromagnetic coil is used for the vibration mechanism. For example, the vibration mechanism is configured by appropriately combining mechanical elements such as a link, a locking claw, and a lever, and by pressing down the lever. The provision and release of the initial displacement may be performed.

In this embodiment, the reaction body fixed to the base is an electromagnet, and a part of the mass is a magnet. However, the mass is formed entirely of a magnetic body, and an initial displacement is given only by suction. You may do so. Further, the reaction body may be a permanent magnet, and a part of the mass body may be an electromagnetic coil.

As in the first embodiment, the output signal from the signal processing means or the detected waveform from the accelerometer is taken out via a cable or the like, processed by a personal computer or the like, and displayed on a CRT or the like. The degree of hardening of the concrete may be monitored. Further, the amplification 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 obtained after the vibration may be used instead of the A / D converter.

(Third Embodiment) Next, a concrete hardening degree judging device 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 diagram showing a concrete hardening degree judging device 31 according to the third embodiment. As can be seen from the figure, the concrete hardening degree determining device 31 of the present embodiment has the vibration mechanism 27 mounted in the base 5 and the vibration mechanism 2 in the same manner as the concrete hardening degree determining device 21 described above.
Hollow electromagnetic coil 24 as a vibrating mechanism for vibrating 7
And a drive circuit 23 for driving the same.

Further, the base 5 incorporates an accelerometer 8 as a vibration detecting means for detecting the vibration of the base 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 first or second embodiment described above in that the comparison circuit 33 reads the output data converted into digital data by the A / D converter 13 from the setting circuit 34 in the comparison circuit 33. When the output data exceeds the set value, a control signal for operating the drive circuit 23 is generated by the timing circuit 35, and when the output data falls below the set value, The notification circuit 36 makes a predetermined notification.

Here, the setting circuit 34 stores, as set values, amplitude data when the degree of hardening of the concrete is suitable for finishing. Such a set value may be determined with reference to an experimental result obtained by examining the correspondence between the hardened state of the concrete and the amplitude of the base.

The concrete hardening degree judging device 3 of this embodiment
In FIG. 8, as shown in the flowchart of FIG. 8, first, the drive switch 22 is depressed to make the drive circuit 23 operable.
Generates a control signal at predetermined time intervals (step 111), and drives the electromagnetic coil 24 in response to the control signal (step 112).

Then, each time the electromagnetic coil 24 receives the control signal, it applies an initial displacement to the mass body 26 to release it, and causes the vibration mechanism 27 to vibrate freely.

Next, the vibration of the base 5 is detected by the accelerometer 8 (step 113). Then, the acceleration waveform of the base 5 detected by the accelerometer 8 is amplified by the amplifier circuit 11 and the built-in integration 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,
The amplitude data in the case where the poured concrete has hardened to a state suitable for concrete finishing is compared with the output data converted into digital 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 falls 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). Various methods can be considered for the notification method. For example, an electronic buzzer built in the notification circuit 36 sounds, a built-in LED is also turned on, or a command is sent to an externally connected personal computer for centralized monitoring. It is good to send. Further, in order to know the curing status in the middle of the process separately from the notification, the same display unit 10 as in the first or second embodiment may be provided in parallel.

The present embodiment has the same effect as the second embodiment, and therefore the description thereof is omitted. In the present embodiment, in particular, the set value for determining the concrete hardening time is set in advance. The set value is compared 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 operated again after a predetermined time has elapsed to activate the vibration mechanism. When the output data became smaller than the set value and the concrete was finished, it was notified by the notification circuit.
The timing of concrete finishing can be accurately grasped.

In this embodiment, the vibration mechanism is automatically driven at predetermined time intervals by providing the timing circuit. However, this may be omitted in some cases.
In the case of such a configuration, the operator manually presses the drive switch at predetermined time intervals, and in each case, checks whether or not the notification circuit issues a notification that the concrete is ready for finishing. If it is not yet time for finishing, the notification to that effect should be made in a form that can be distinguished from the above-mentioned notification, for example, by changing the buzzer sound or changing the color of the display lamp. You may.

Further, in the above embodiments, attention was paid to how the magnitude of the amplitude changes. However, the parameter for determining the degree of hardening of the concrete is not limited to the amplitude of the vibration. Alternatively or additionally, the damping rate of the vibration at each time may be adopted. That is, a lot of time history data as shown in FIG. 4 is collected between the time the concrete is cast and the time the concrete is hardened, and the degree of hardening of the concrete is determined based on the difference in the attenuation rate evaluated from the data. You may.

In all of the above-described embodiments, the vibration mechanism is configured to freely vibrate. However, the vibration mechanism is forcibly vibrated, that is, the drive circuit in the second and third embodiments is provided with an AC power source to provide electromagnetic force. An AC 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 during that time using the amplitude and the damping rate as parameters.

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

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

[0084]

As described above, according to the apparatus for determining the degree of hardening of concrete of the present invention, it is possible to directly grasp the state of hardening of concrete, and conventionally, it has relied on the experience of plasterers and cans. It is possible to objectively determine when to finish concrete.

Further, according to the method for judging the degree of concrete hardening of the present invention, it is possible to directly grasp the state of hardening of the concrete, and it is possible to determine the concrete finishing time which has conventionally depended on the experience of plasterers and cans. Judgment can be made objectively.

[0086]

[Brief description of the drawings]

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

FIG. 2 is a graph showing experimental results.

FIG. 3 is an explanatory view showing the operation of the concrete hardening degree determination device according to the embodiment.

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

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

FIG. 6 is a flowchart illustrating the operation of the concrete hardening degree determination device according to the second embodiment.

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

FIG. 8 is a flowchart illustrating the operation of the concrete hardening degree determination device according to 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 Protrusive leg 8 Accelerometer (vibration detecting means) 9, 32 Signal processing means 10 Display Unit 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

Continuation of the front page (56) References JP-A-56-649 (JP, A) JP-A-5-322286 (JP, A) JP-B 64-11889 (JP, B2) (58) Fields investigated (Int) .Cl. ⁷ , DB name) G01N 11/00-11/16 G01N 19/00-19/10 G01N 3/00-3/62 G01N 33/38 G01N 29/00-29/28 JICST file (JOIS)

Claims (8)

(57) [Claims] 1. A base, to which a vibration mechanism including a mass body and a spring is fixed, and vibration detecting means capable of detecting vibration of the base, wherein the vibration mechanism is configured to connect one end of the spring to the base.
The concrete hardening degree determination device , wherein the other end is attached to the mass body, respectively . 2. The concrete hardening degree judging device according to claim 1, further comprising a vibration mechanism for vibrating the vibration 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 judging device according to claim 2, wherein the device is configured as: 4. A setting circuit capable of presetting a predetermined vibration value such as an amplitude and a damping rate at the time of concrete hardening, a comparison circuit for comparing the set value with an output value of the vibration detecting means, 3. The concrete hardening degree judging device according to claim 2, further comprising: a notifying circuit for performing a predetermined notification when the value falls below the set value. 5. A timing circuit for generating a control signal at predetermined time intervals until the output value falls below the set value;
5. The concrete hardening degree judging device according to claim 4, further comprising a drive circuit for operating the vibration mechanism in response to the control signal. 6. The vibration mechanism fixes a predetermined reaction body to the base so as to face the mass body, and configures one of the reaction body and the mass body as an electromagnet and the other as a magnet. 3. The concrete hardening degree judging device according to claim 2, wherein an AC voltage is applied to said electromagnet so that said vibration mechanism can be steadily vibrated at a predetermined frequency. 7. The concrete hardening degree judging device according to claim 1, wherein a projecting leg is attached to the concrete contact surface of the base. 8. A spring having one end connected to a base and the other end connected to a mass body.
The bases to which the respective vibration mechanisms are attached are fixed to the vicinity of the surface of the concrete, and then the base is vibrated to detect the vibration of the base, and then the detected vibration value is monitored. Alternatively, a concrete hardening degree judging method characterized in that the vibration value is compared with preset values such as an amplitude and a damping rate to determine the degree of concrete hardening.