JPH04212088A - Concrete sensor - Google Patents

Abstract

PURPOSE:To detect only concrete not hardened on the basis of the difference between the electromotive force of the electrode immersed in the concrete not hardened and that of the electrode immersed in water. CONSTITUTION:An auxiliary electrode 2c is provided in parallel to one electrode 2b among two electrodes 2a, 2b and a lead wire is led out of the junction point of the electrode 2b and the auxiliary electrode 2c and a separate lead wire is led out of the other electrode 2a and these electrodes are formed by combining metals so that the polarities generated in two lead wires when the electrodes are immersed in concrete not hardened and in water are reversed.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a sensor for detecting muddy soil containing cement components, such as fresh concrete and mortar, and particularly to a concrete sensor capable of distinguishing between water and muddy soil. It is.

0002

[Prior Art] When constructing a concrete structure, it is common to pour fresh concrete between, for example, wooden formwork, between the formwork and an excavated wall surface, or between a lining wall that is lined therewith. However, in order to construct high-quality concrete, it is necessary to check the filling status of fresh concrete while compacting it.

[0003] However, it is difficult to check the filling status with the naked eye because it is obstructed by the formwork's sheathing and shoring, so conventionally an expert person hammered the formwork with a mallet and judged based on the sound of the impact. I relied heavily on intuition and experience.

[0004] When concrete is actually compacted, concrete is filled in by hammering the areas determined to be filled with concrete through percussion using a mallet, or by vibrating the formwork with a vibrator. However, if the percussion is inaccurate, the formwork may be damaged due to blank casting, and it may also lead to insufficient concrete filling.

[0005] In this way, when it is difficult to visually confirm the pouring of fresh concrete, it is done only by sounding and based on intuition and experience, so it is ambiguous, and compaction, which is a subsequent work, is difficult. Despite sometimes being forced to waste effort, there is a problem of insufficient concrete filling. Another problem is that the work environment is unsuitable for young workers despite the harsh nature of the work.

Therefore, in recent years, a sensor for electrically determining the concrete placement situation has been developed.
Technologies such as No. 101823 and Japanese Patent Publication No. 64-1621 have been proposed. These techniques use a pair of electrodes, and when fresh concrete is filled between the electrodes attached to the formwork, a current flows between the electrodes using the moisture as a conductor, which is used as the detection element.

[0007]

[Problems to be Solved by the Invention] However, in the above-mentioned prior art, the sensor detects water;
It's not actually ready-mixed concrete. In other words, since fresh concrete contains water, the detection is based on the assumption that detecting water is equivalent to detecting fresh concrete, so strictly speaking, it is absolutely reliable. There is no gender.

By the way, in preparation for pouring fresh concrete, the wooden formwork is sufficiently sprinkled with water. This is done by cleaning the surface of the formwork, and if the formwork absorbs water contained in the fresh concrete, the moisture content of the concrete will decrease, causing poor hardening of the concrete. The purpose is to keep the frame sufficiently moistened with water. Additionally, excess water may adhere to the formwork due to rainfall or water leakage from the excavated wall surface. Therefore, even if no water is used before pouring, it is currently fatal that there is no meaning in detecting water using conventional sensors and determining that it is the detection of ready-mixed concrete. There are also some problems.

In view of these conventional drawbacks, the present invention aims to provide a concrete sensor that can reliably identify water and fresh concrete as different detection elements and accurately detect the presence of fresh concrete. do.

0010

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention first provides an auxiliary electrode in parallel with one of the two electrodes, and connects this one electrode with the auxiliary electrode. A lead wire is led out from the junction of the electrodes, and another lead wire is led out from the other electrode, and these electrodes are immersed in water and ready-mixed concrete so that the polarity of the two lead wires is reversed. We used a method of combining metals.

Next, as shown in claim 2, an auxiliary electrode having an area approximately equal to that of one of the two electrodes is bonded to one of the two electrodes, and a lead wire is led out from this auxiliary electrode. Another lead wire is taken out from the other electrode, and these electrodes are immersed in water and ready-mixed concrete as described above.
We used a combination of metals that reversed the polarity of the book's lead wires.

Furthermore, thirdly, as shown in claim 3,
This is a concrete sensor in which lead wires are derived from two electrodes, and these electrodes are made of a combination of metals that produce different voltage values in the two lead wires when immersed in water and immersed in ready-mixed concrete. I decided to use it.

[0013]

[Embodiment] Hereinafter, one embodiment of the present invention will be described in detail with reference to the attached drawings. The configuration shown in FIG. , 2b is an electrode on the opposite side, 2c is an auxiliary electrode electrically connected to electrode 2b, 3 is a housing made of an insulator, 4 fixes this concrete sensor 1,
It is also a socket for electrically connecting to a detection device to be described later, and has two lead wires extending from each electrode facing the socket hole on the bottom surface. Then, a plurality of concrete sensors 1 are used and each is fixed at a required location on the formwork to detect the voltage generated by pouring fresh concrete and perform diagnosis.

FIG. 2 shows the electrodes 2a and 2 of the concrete sensor 1.
This diagram schematically shows the relationship between the electrode 2b and the auxiliary electrode 2c.The lead wire 5a is led out from the electrode 2a, and the
Another lead wire 5b is led out from the junction point 6 between the lead wire 5b and the auxiliary electrode 2c, and each lead wire 5b is connected to the metal fitting of the socket hole. Here, three different metals are used for the electrodes 2a and 2b and the auxiliary electrode 2c. Although there are multiple combinations of these metals, an example will be described below in which zinc is used as the electrode 2a, aluminum is used as the electrode 2b, and tin is used as the auxiliary electrode 2c.

First, when this concrete sensor 1 was immersed in water with a neutral pH of 7 with the relationship between the electrode 2b and the auxiliary electrode 2c electrically disconnected, the electromotive force generated in each electrode was measured. The tin auxiliary electrode 2c is positive and the zinc electrode 2a is negative.
A voltage of 5V was generated. The area of the electrodes 2a and 2b at this time is approximately 3 square cm each, and the area of the auxiliary electrode is 1/1 of that.
It is about 0. Further, no electromotive force was generated between the zinc electrode 2a and the aluminum electrode 2b. Next, the aluminum electrode 2b and the auxiliary electrode 2c were electrically integrated at the junction 6, and the lead wire 5b was derived from this to form the original structure of the concrete sensor 1, and the voltage between the lead wires 5a and 5b was measured. Similarly, a voltage of 0.5V was generated by setting the lead wire 5a as a negative wire and the lead wire 5b as a positive wire.

Next, the same concrete sensor 1 was immersed in fresh concrete (about pH 13), which is alkaline in nature, and the electromotive force was measured. At this time, an electromotive force of about 0.3V was generated between the zinc electrode 2a and the tin auxiliary electrode 2c, with the polarity being the same as in the case of water, with the zinc electrode 2a being negative and the auxiliary electrode 2c being positive. Furthermore, zinc electrode 2
An electromotive force of 0.8V was generated between the aluminum electrode 2a and the aluminum electrode 2b, with the zinc electrode 2a being positive and the aluminum electrode 2b being negative. Then, as in the case of water, the aluminum electrode 2b and the auxiliary electrode 2c were joined and electrically integrated, and the voltage was measured between the lead wire 5b led out from this and the lead wire 5a led out from the zinc electrode 2a. In the case of water, the polarity was reversed, and a voltage of 0.5V was generated with the lead wire 5a being positive and the lead wire 5b being negative. This value means that since the aluminum electrode 2b and the auxiliary electrode 2c are electrically short-circuited, their respective voltages cancel each other out at the junction point 6, and the voltage of the aluminum electrode 2b (minus 0.8V) and the voltage of the auxiliary electrode ( plus 0.3
V).

By the way, this concrete sensor 1 is called P
When immersed in dilute hydrochloric acid with an H value of about 3, the lead wire 5a.
The polarity between 5b is the same as in the case of water, and its electromotive force is 0.
．． It was about 2V.

As described above, when the concrete sensor 1 of this embodiment is used, two lead wires 5a and 5 are used when immersed in water and when immersed in alkaline fresh concrete.
Although the absolute value of the voltage generated at b is the same, the polarity is reversed. This is considered to be dependent on the pH value of the solution to be immersed and the ionization tendency of the three types of metals. Therefore, if the voltage generated by this concrete sensor 1 is input to the detection device which is a subsequent electric circuit, the polarity of the output voltage will be reversed in the case of water and in the case of fresh concrete. It is also possible to freely change the detection circuit so that it does not work and the detection circuit works in the case of fresh concrete, or vice versa, so that a reliable judgment can be made. Also,
Even acid rain, which has become a problem in recent years, has the same polarity as neutral water, so the detection results will not be reversed.

In this embodiment, the zinc electrode 2a and the tin auxiliary electrode 2c are described, but it is sufficient if the metal material on the surface is zinc or tin; for example, the zinc electrode 2a is made of a galvanized iron plate ( For the auxiliary electrode, a tin steel plate (tin plate) is sometimes used. In any case, the present invention includes all metal combinations in which the polarity of the current generated in the lead wire is reversed when it is immersed in water and when it is immersed in fresh concrete.

Further, in this concrete sensor 1, the electromotive force changes even when contact with the fresh concrete is cut off after being immersed in the fresh concrete. That is, when immersed in fresh concrete, a voltage of 0.5V is generated with the lead wire 5a being positive and the lead wire 5b being negative, but when this is pulled out of the fresh concrete, after a certain period of time, a voltage of 0.5V is generated. Once again, the polarity between the two leads is reversed, similar to the case with water. The reason for this is that a certain amount of alkaline solution adheres to the surroundings of concrete sensor 1, that is, to the electrodes when it is lifted from fresh concrete, so the same chemical reaction continues when it is immersed in fresh concrete. Since the amount of alkaline solution used is limited, the chemical reaction will become saturated over time, and after that the product will return to the same state as if it had been immersed in neutral water. The time required for the polarity to change is between the aluminum electrode 2b and the auxiliary electrode 2c.
depends on the area ratio of In other words, although the magnitude of the voltage itself does not change, the larger the area of the auxiliary electrode 2c, the stronger the effect of lowering the electromotive force of the aluminum electrode 2b and the zinc electrode 2a, so the time required for the chemical reaction to reach saturation becomes shorter. . Therefore, the changing time can be freely set by adjusting the area of the auxiliary electrode 2c. If these effects are actively utilized, for example, even if the fresh concrete in this area moves for some reason after it has been placed in the area corresponding to the concrete sensor, it will be possible to reliably detect the situation. can.

Furthermore, FIG. 3 schematically shows a second embodiment based on the invention set forth in claim 2. In this embodiment, the zinc electrode 2a is the same as in the first embodiment, but the aluminum electrode 2b and the tin auxiliary electrode 2
The area ratio of c is almost equal, and the lead wire 5b is connected to the auxiliary electrode 2.
I tried to derive it from c. In this case, the aluminum electrode 2b and the auxiliary electrode 2c are electrically short-circuited via the boundary line 7, but the relationship in electromotive force is the same as in the first embodiment. The reason why the area of the aluminum electrode 2b and the area of the auxiliary electrode 2c are made almost equal and the area ratio of the auxiliary electrode 2c is made higher than in the first embodiment is because the two are short-circuited, so that the area of the tin when immersed in water is This is because it is necessary to cancel out the influence of the aluminum electrode 2b on the auxiliary electrode 2c. Further, even in this case, the time for returning the polarity when contact with fresh concrete is cut off can be adjusted by adjusting the area ratio of the aluminum electrode 2b and the auxiliary electrode 2c.

[0022] As for the metal used for the electrode, for example, if lead is used instead of tin for the auxiliary electrode 2c, the results are almost the same as those described above. This is because tin and lead are adjacent to each other in the ionization row and are close to each other.

Next, as a third configuration shown in claim 3,
Some devices use two electrodes, ie, a pair of electrodes, and omit the auxiliary electrode. In this example, a copper electrode and an aluminum electrode were used as the two electrodes, but in this case, the effective area of each electrode was 2 cm2, and when immersed in water, the copper electrode was set as positive and the aluminum electrode was set as negative. 45
V. When immersed in fresh concrete, an electromotive force of 1.10V was obtained. Although there is no polarity reversal occurring in the lead wire in this example, the "threshold value" is approximately 0.6V, for example.
If the concrete sensor is electrically connected to a detection circuit that is activated when the sensor exceeds this value, it is possible to identify whether the medium in which the concrete sensor is immersed is water or fresh concrete. Note that the metals used for the electrodes are not limited to the copper electrode and aluminum electrode in this example, but any combination of metals that has a difference in electromotive force that can be discerned when both are immersed in water and when they are immersed in fresh concrete can be used. For example, it is within the scope of the present invention.

There is also a modified example of the shape of the concrete sensor shown in FIG. Here, for ease of explanation, parts that perform the same functions as those in FIG. 1 are given the same numbers. In short, the electrode 2 is placed on the outer periphery of the insulator housing 3.
A, 2b and an auxiliary electrode 2c are formed. With such a configuration, as shown in FIG. 5, if the housing 3 is extended into a cylindrical shape, electrodes are provided at appropriate intervals, and lead wires are drawn out from each of the electrodes to the inside of the housing 3. It is possible to use a bar-shaped sensor on which a plurality of concrete sensors are installed. Furthermore, Figure 5
In the figure, 8 is a formwork, 9 is a fixture for attaching the sensor to the formwork, and 10 is a screw for attachment to the formwork 8.

Next, in order to detect the presence of fresh concrete using the concrete sensor of this embodiment, a configuration as shown in FIG. 6 is used. In the figure, reference numeral 11 surrounded by a dotted line is the rod-shaped sensor shown in FIG. Then, each signal is inputted to the detection device 13 via the detection output cable 12, and the detection status of each concrete sensor is determined by this detection device 13. The detection device 13 includes an indicator light 14 for displaying the operating status of each concrete sensor, a communication cable 15 for outputting this operating status to the outside, and a test button 16 for checking each concrete sensor.
It is equipped with a power switch 17, a power indicator light 18, and the like.

An embodiment of the detection device 1 is shown in FIG. 7, which includes a power connector 19 connected to a 100V or 200V commercial AC power source, a voltage changeover switch 20 for selecting between 100V and 200V, Power connector 1
a rectifier circuit 21 that rectifies the alternating current input into the detector 9 into low-voltage direct current, and a constant voltage circuit 22 that supplies direct current voltage to all circuits in the detection device without changing the output voltage significantly in response to load fluctuations. , a number of detection circuits 23 corresponding to the number of concrete sensors 1, and a test circuit 2 connected to the test button 16.
4, an amplification output section 25 for amplifying the voltage of the detection circuit 23, the indicator lamp 14, a buzzer circuit 26, and a buzzer 27 that are controlled and lit by the amplification output section 25.
, and further includes a switch 28 for stopping the buzzer. Further, a communication output section 29 and a communication output connector 30 are provided to output the signal of the amplification output section 25 to the outside.

[0027] In the detection device 13 configured in this way,
Each detection circuit 23 is connected to an amplification output section 25, and after the detection voltage is amplified by this output section 25, the indicator lamp 14 is turned on. Furthermore, when the all-concrete sensor connected to the detection device 13 detects the presence of fresh concrete, the buzzer circuit 26 operates to drive the buzzer 27 to alert the worker. Note that a remote buzzer terminal 31 is provided to drive another buzzer via a cable when it is necessary to draw the attention of a distant worker. Also,
If the indicator light 14 is color-coded using a light emitting diode, visual confirmation will be easier.

[0028]

Effects of the Invention In the present invention, the ionization tendency of the electrode and the P
Depending on the H value, the polarity of the voltage generated in the lead wire will be reversed when it is immersed in water and when it is immersed in fresh concrete. Therefore, if the detection signal of this concrete sensor is input to the subsequent detection device, it becomes possible to not operate the circuit in the case of water, but to operate the detection device in the case of fresh concrete, depending on the polarity. We were able to reliably judge the placement status of ready-mixed concrete. In addition, if this sensor is immersed in fresh concrete and then loses contact, the polarity will be reversed again, so it is possible to detect even if the fresh concrete moves after a certain amount of time has passed since pouring. , resulting in a highly safe and reliable concrete sensor.

Furthermore, in the second invention, since one electrode and the auxiliary electrode are connected and the surface areas are approximately equal, one electrode is constructed with twice the area, and the auxiliary electrode is half of that area. Since the electrode can be manufactured by a simple process of plating the metal to be used, the performance is the same as the first invention, cost can be reduced, and it is effective for mass production.

Furthermore, since the third invention uses only two electrodes without requiring an auxiliary electrode, it is easy to manufacture like the second invention. In addition, since there is a large difference in electromotive force between water and ready-mixed concrete, it is possible to set a "threshold" relatively easily to identify the relationship between the two, which is an inexpensive method. This enabled reliable detection.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of a concrete sensor of the present invention;

FIG. 2 is a schematic diagram showing the electrode of the first invention;

[Figure 3] Second
A schematic diagram showing the electrode of the invention,

FIG. 4 is a perspective view showing a modified example of the concrete sensor of the present invention;

FIG. 5 is a cross-sectional view showing a plurality of modified examples of FIG. 4 connected;

[Fig. 6] A schematic diagram showing the concrete sensor shown in Fig. 5 attached to the formwork;

FIG. 7 is a schematic block diagram of a detection device to which a concrete sensor is connected.

[Explanation of symbols]

1 Concrete sensor 2a/2b electrode 2c Auxiliary electrode 5a/5b Lead wire 6 Junction point

Claims (3)

[Claims] Claim 1: An auxiliary electrode is provided in parallel to one of the two electrodes, a lead wire is led out from the junction of the one electrode and the auxiliary electrode, and another lead wire is led out from the other electrode. The concrete sensor is characterized in that these electrodes are made of a combination of metals whose polarities in the two lead wires are reversed when immersed in water and fresh concrete. 2. An auxiliary electrode having approximately the same area as the auxiliary electrode is bonded to one of the two electrodes, a lead wire is led out from the auxiliary electrode, and another lead wire is led out from the other electrode, A concrete sensor characterized in that these electrodes are made of a metal combination in which the polarity of the two lead wires is reversed when immersed in water and fresh concrete. 3. A concrete sensor in which lead wires are led out from two electrodes, and these electrodes are made of metal that produce different voltage values in the two lead wires when immersed in water and when immersed in ready-mixed concrete. A concrete sensor characterized by being combined.