WO2022065595A1 - Strength signal measuring method and device for monitoring strength of hydration reaction material structure - Google Patents

Abstract

The present invention provides a strength signal measuring method and device for monitoring strength of a hydration reaction material structure. A concrete structure or the like, which is a sort of structure formed of a hydration reaction material, exhibits a transmission speed inside the material and a response characteristic based on an excitation frequency, which are different according to strength, elastic modulus, and the like when vibration by an external factor is applied to. This may be used to measure strength of a structure and the ground to reliably monitor strength of a structure. The device can be made compact to secure portability and mobility, thereby measuring strength regardless of location.

Description

Intensity signal measuring method and intensity signal measuring device for monitoring the strength of the hydration reactant structure

The present invention relates to a strength signal measuring method and strength signal measuring apparatus for monitoring the strength of a hydration reactant structure, and more particularly, to a concrete structure, which is a type of structure made of a hydration reactant, when vibration is applied by an external factor. Since the speed at which the material is delivered is different according to the strength and modulus of elasticity, and the response characteristics according to the input frequency are different, it is possible to reliably monitor the strength of the structure by measuring the strength of the structure and the ground using this. It relates to a strength signal measuring method and a strength signal measuring device for monitoring the strength of a hydration reactant structure, which can measure the strength of the structure regardless of location by securing portability and portability because it can be manufactured.

Recently, social and public core structures have been increasing due to the expansion of social infrastructure for economic and industrial development in Korea as well as in countries around the world, and the scale of these constructions continues to increase.

Concrete is widely used as the most common and general structural material in building production, and research on performance improvement and stable quality control is being actively conducted.

In particular, in concrete structures, strength is a basic factor to evaluate the stability of a structure, and securing the required strength and maintaining homogeneity is essential to secure the stability of the structure itself, and it is a basic criterion for evaluating various other properties.

The strength of concrete is treated as the most important factor in quality control. However, since the quality control of concrete is mainly based on the strength of 28 days of standard curing, there is a time difference between the progress of construction and the time of strength evaluation. The results of the quality test of hardened concrete cannot be reflected in the construction work quickly, and when the required strength is excessive or insufficient, it becomes difficult to deal with strength problems such as safety issues as well as economic and administrative losses.

The concrete curing strength estimation method uses the method using the integrated temperature or the method using the Schmitt hammer.

This does not directly measure the inside of the concrete structure, but has a problem in that it is difficult to accurately estimate the strength and to estimate the strength in real time, and there are other problems in that it is difficult to measure when the accessibility of the measurement point is difficult.

In addition to the method using the integrated temperature, most studies related to the evaluation of the expression strength of the existing cast-in-place concrete target the electrochemical acceleration method and various non-destructive test methods.

In addition, not only the theoretical formula proposed by mathematical modeling, but also the form of an expression based on actual experiments or experience is being proposed. It is not currently being used.

In other words, the strength of the concrete structure constructed by pouring ready-mixed concrete and the ground improved by a method such as DCM is gradually expressed by the hydration reaction of the cement, which is its constituent. That is, since the intensity value changes with time, there is a limit in which the intensity cannot be accurately known without taking a sample.

It is possible to estimate the strength of a structure indirectly by manufacturing a specimen at the time of construction such as pouring ready-mixed concrete and performing a strength test, but it is not possible to know the direct strength of the structure. Since it is measured by finding the limit value of Therefore, physical characteristics such as strength and modulus of a structure can be estimated using ultrasonic waves or elastic waves or by non-destructive methods such as GPR, but it is difficult to apply these methods in a low-intensity state in the initial stage of the hydration reaction.

Accordingly, it is necessary to prevent the collapse of facilities in advance by detecting abnormal behavior through efficient real-time measurement and monitoring that considers the evaluation of strength development of cast-in-place concrete structures and taking appropriate measures.

Therefore, the present invention for solving the above-mentioned problems of the prior art, the concrete structure, which is a kind of structure made of a hydration reaction material, when vibration is applied by external factors, the speed transmitted inside the material according to the strength and elastic modulus, etc. To provide a strength signal measuring method for monitoring the strength of a hydration reactant structure, which enables reliable monitoring of the strength of the structure by measuring the strength of the structure and the ground using it, and the response characteristics according to the excitation frequency are different. There is a purpose.

In addition, another object of the present invention is to provide a strength signal measuring device for monitoring the strength of the hydration reactant structure, which can be manufactured in miniaturization and can measure strength regardless of location by securing portability and mobility.

The problems to be solved of the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

According to one aspect of the present invention for achieving the objects and other features of the present invention, it is connected to a piezoelectric element installed in a structure made of a hydration reactant material to generate and measure an intensity signal for measuring the strength of the hydration reactant structure A method for measuring the strength of a hydration reaction material structure through an intensity signal measuring device comprising: an AC electrical signal generating step of generating an AC electrical signal of a specific waveform having a frequency of a predetermined frequency band; an AC electrical signal applying step of applying the generated AC electrical signal to the piezoelectric element for a predetermined time; a frequency-impedance detection step of detecting a change in the resonance frequency and impedance of the piezoelectric element according to the frequency of the AC electrical signal applied in the AC electrical signal application step; and a pressure change measuring step of measuring a change in physical pressure applied to the piezoelectric element as an intensity signal based on the detected change in resonance frequency and impedance of the piezoelectric element. A method for measuring an intensity signal for monitoring is provided.

In one aspect of the present invention, the step of generating the AC electrical signal consists of sequentially generating an AC electrical signal in the form of a sine wave having a predetermined frequency band for a predetermined time, the frequency band of the AC electrical signal and the The generation time is characterized in that it is determined according to the frequency characteristics of the piezoelectric element.

In one aspect of the present invention, the pressure change detecting step is made to detect the amplified electric signal after amplifying the electric signal according to the change in the impedance and the resonance frequency of the piezoelectric element according to the frequency of the AC electric signal, , in the pressure change measuring step, the AC electrical signal generated from the AC electrical signal generator is removed through a low-pass filter, and only the electrical signal according to the change in the resonance frequency and impedance of the piezoelectric element is passed to measure the electrical signal can be done

In one aspect of the present invention, when the resonance frequency and impedance generated in the piezoelectric element are detected in the frequency-impedance detection step, the temperature around the impedance is detected and the measured resonance frequency and impedance are corrected to minimize the measurement error. The method further includes; in the correcting step, a resonant frequency and a corrected impedance may be obtained through Equations 1 and 2 below.

f = f1 + A * (Tc-Tref) + B (Equation 1)

z = z1 + C * (Tc-Tref) + B (Equation 2)

(here, f: corrected resonance frequency, z: corrected impedance, f1: measured resonance frequency, z1: measured impedance, A: temperature characteristic coefficient of piezoelectric element 1, C: temperature characteristic coefficient of piezoelectric element 3, B: temperature characteristic coefficient of piezoelectric element 2, D: temperature characteristic coefficient of piezoelectric element 4, Tc: measured current temperature, Tref: reference temperature, A, B, C, D and Tref are the temperature characteristic tests for piezoelectric element. constant value obtained through

According to another aspect of the present invention, as an intensity signal measuring device connected to a piezoelectric element installed in a structure made of a hydration reaction material to generate and measure an intensity signal for measuring the strength of the hydration reaction material structure, the control module is provided in the piezoelectric element a device housing configured with a connector to which the accessory is electrically connected; an AC electrical signal generator provided in the device housing and configured to generate an AC electrical signal of a specific waveform having a frequency of a predetermined frequency band; It is provided in the device housing, and the AC electrical signal generator controls to generate an AC electrical signal of a specific waveform having a frequency of a predetermined frequency band, applies the generated AC electrical signal to the piezoelectric element, and applies the generated AC electrical signal to the piezoelectric element a control module unit for measuring a change in physical pressure applied to the piezoelectric element based on the obtained AC electrical signal; and a power supply unit provided in the device housing and configured to supply necessary power to the control module unit; a strength signal measuring device for monitoring the strength of the hydration reactant structure comprising a.

In another aspect of the present invention, the AC electrical signal generator comprises a sine wave signal generator that generates an AC electrical signal of a sine wave having a predetermined frequency band, and the control module includes an AC electrical signal generated by the sine wave signal generator. An AC electrical signal control unit to control and apply to the piezoelectric element, and a frequency-impedance detection unit for detecting a change in the resonance frequency and impedance of the piezoelectric element according to the frequency of the AC electric signal applied to the piezoelectric element, and the frequency-impedance It may include a pressure change measuring unit that measures a change in physical pressure applied to the piezoelectric element based on a change in the resonance frequency and impedance of the piezoelectric element detected by the detection unit.

In another aspect of the present invention, the control module unit, a signal amplifying unit for amplifying the magnitude of the electric signal according to the change in the resonance frequency and impedance of the piezoelectric element; a low-pass filter unit configured to remove an AC electrical signal generated by the AC electrical signal generator among the electrical signals outputted from the signal amplifying unit, and to pass only an electrical signal according to a change in the resonance frequency and impedance of the piezoelectric element; and an analog-to-digital converter unit configured to convert and output an analog electrical signal according to a change in the resonance frequency and impedance of the piezoelectric element filtered through the low-pass filter unit and output to a digital signal.

In another aspect of the present invention, the device housing to transmit pressure change data measuring the change in physical pressure applied to the piezoelectric element based on the digital signal of the resonance frequency and impedance change of the piezoelectric element to an external upper processing device. a wired/wireless communication module unit provided; and a GPS module provided in the device housing and configured to transmit the location information of the piezoelectric element to an external higher-level processing device.

In another aspect of the present invention, the control module unit calculates and calculates the intensity based on the pressure change data measuring the change in physical pressure applied to the piezoelectric element based on the digital signal of the resonance frequency and impedance change of the piezoelectric element The apparatus further comprises a strength calculation unit, wherein the apparatus for measuring the strength signal comprises: a wired/wireless communication module unit provided to transmit the strength data calculated by the strength calculation unit to an external upper processing device; and the strength data calculated by the strength calculation unit It may further include; a display unit for displaying, and a GPS module unit provided in the device housing and configured to transmit the location information of the piezoelectric element to an external higher-level processing device.

In another aspect of the present invention, a temperature sensor installed on the lower end surface of the device housing to detect an ambient temperature of the impedance, and the control module unit are configured, and the frequency-resonance frequency and impedance of the piezoelectric element in the impedance detection unit When detecting , the frequency-impedance correction unit to minimize the measurement error by correcting the measured resonance frequency and impedance value based on the temperature detected by the temperature sensor; further comprising, wherein the frequency-impedance correction unit, The corrected resonant frequency and corrected impedance can be obtained through Equations 1 and 2.

f = f1 + A * (Tc-Tref) + B (Equation 1)

z = z1 + C * (Tc-Tref) + B (Equation 2)

(here, f: corrected resonance frequency, z: corrected impedance, f1: measured resonance frequency, z1: measured impedance, A: temperature characteristic coefficient of piezoelectric element 1, C: temperature characteristic coefficient of piezoelectric element 3, B: temperature characteristic coefficient of piezoelectric element 2, D: temperature characteristic coefficient of piezoelectric element 4, Tc: measured current temperature, Tref: reference temperature, A, B, C, D and Tref are the temperature characteristic tests for piezoelectric element. constant value obtained through

According to the intensity signal measuring method and intensity signal measuring apparatus for monitoring the intensity of the hydration reactant structure according to the present invention, the following effects are provided.

First, the present invention has the effect of reliably measuring the strength of the structure using the impedance characteristics of the piezoelectric element and providing continuous monitoring.

Second, since the present invention can be manufactured in a small size, portability and portability can be secured, and accordingly, strength can be easily measured regardless of location.

Effects of the present invention are not limited to those mentioned above, and other solutions not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a flowchart schematically illustrating a method for measuring an intensity signal for monitoring the intensity of a hydration reactant structure according to the present invention.

2 is the resonance of the piezoelectric element according to the frequency change of the AC electrical signal applied to the piezoelectric element in a state in which no pressure is applied to the piezoelectric element in the method for measuring the intensity signal for monitoring the intensity of the hydration reactant structure according to the present invention; A graph measuring the signal output through the low-pass filter with respect to the frequency characteristic and the impedance characteristic.

3 is a resonant frequency characteristic of a piezoelectric element according to a change in the frequency of an AC electrical signal applied to the piezoelectric element in a state in which a constant pressure is applied to the piezoelectric element in the intensity arc measurement method for monitoring the strength of the hydration reactant structure according to the present invention; A graph measuring the signal output through the low-pass filter with respect to the impedance characteristic.

4 is a graph showing the relationship between temperature, resonant frequency, and impedance;

5 is a graph used in the calibration process of the intensity signal measuring method for monitoring the intensity of the hydration reactant structure according to the present invention.

6 is a graph comparing graph 1 and graph 2 of FIG. 5 .

7 is a block diagram schematically showing the configuration of the intensity signal measuring apparatus for monitoring the intensity of the hydration reactant structure according to the present invention.

8 is a block diagram schematically showing the configuration of a control module unit constituting the intensity signal measuring apparatus for monitoring the intensity of the hydration reactant structure according to the present invention.

Additional objects, features and advantages of the present invention may be more clearly understood from the following detailed description and accompanying drawings.

Prior to the detailed description of the present invention, the present invention can make various changes and can have various embodiments, and the examples described below and shown in the drawings are not intended to limit the present invention to specific embodiments. No, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

When an element is referred to as being “connected” or “connected” to another element, it is understood that it may be directly connected or connected to the other element, but other elements may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle.

The terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Also, terms such as “unit”, “unit”, and “module” described in the specification mean a unit that processes at least one function or operation, which may be implemented as hardware or software or a combination of hardware and software.

In addition, in the description with reference to the accompanying drawings, the same components are given the same reference numerals regardless of the reference numerals, and the overlapping description thereof will be omitted. In describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

Hereinafter, a method and an apparatus for measuring an intensity signal for monitoring the intensity of a hydration reaction material structure according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

First, the intensity signal measuring method for monitoring the intensity of the hydration reactant structure according to the present invention will be described in detail with reference to FIG. 1 .

1 is a flowchart schematically illustrating a method for measuring an intensity signal for monitoring the intensity of a hydration reactant structure according to the present invention.

The intensity signal measurement method for monitoring the strength of the hydration reaction material structure according to the present invention is installed in a structure made of a hydration reaction material (for example, a concrete structure constructed by pouring ready-mixed concrete or a ground improved by a method such as DCM) As a method for measuring the intensity signal of the hydration reactant structure through an intensity signal measuring device connected to the piezoelectric element to generate and measure an intensity signal for measuring the intensity of the hydration reactant structure, as shown in FIG. AC electrical signal generating step (S100); AC electrical signal application step (S200); frequency-impedance detection step (S300); and a pressure change measuring step (S400).

Specifically, the intensity signal measuring method for monitoring the strength of the hydration reactant structure according to the present invention is connected to a piezoelectric element installed in a structure made of a hydration reactant material to generate an intensity signal for measuring the strength of the hydration reactant structure, and As a method for measuring the intensity signal of the hydration reaction material structure through the intensity signal measuring device to measure, as shown in FIG. 1, an AC electrical signal generating step of generating an AC electrical signal of a specific waveform having a frequency of a predetermined frequency band (S100); AC electrical signal application step (S200) of applying the AC electrical signal generated in the AC electrical signal generating step (S100) to the piezoelectric element for a predetermined time; Frequency-impedance detection step (S300) of detecting the resonance frequency (intrinsic resonance frequency) and impedance of the piezoelectric element according to the frequency of the AC electrical signal applied in the AC electrical signal application step (S200); and a pressure change measuring step (S400) of measuring a change in physical pressure applied to the piezoelectric element based on the intrinsic resonance frequency and impedance of the piezoelectric element detected in the frequency-impedance detecting step (S300). do.

The AC electrical signal generating step (S100) is a step of generating an AC electrical signal of a specific waveform having a frequency of a predetermined frequency band, and generates an AC electrical signal in the form of a sine wave having a frequency band of a low frequency to a high frequency. It consists of generating sequentially within a certain period of time.

The frequency and generation time of the AC electrical signal generated in the AC electrical signal generating step (S100) are determined according to the frequency characteristics of the associated piezoelectric element. For example, the AC electrical signal generating step (S100) consists of generating a sine wave of 5KHz to 100KHz for 1 second.

Here, the AC electrical signal generating step (S100) is generated by a sine wave signal generator provided in the intensity signal measuring apparatus.

And the AC electrical signal applying step (S200) consists of applying the AC electrical signal generated in the AC electrical signal generating step (S100) to the piezoelectric element for a predetermined time.

Here, the AC electrical signal application step (S200) is made to generate and apply an AC electrical signal set according to the frequency characteristics of the piezoelectric element in the sine wave signal generator through the control module unit provided in the intensity signal measuring device.

Subsequently, in the frequency-impedance detection step (S300), the resonance frequency (intrinsic resonance frequency) and impedance (resonance) generated in the piezoelectric element by the frequency of the AC electrical signal applied in the AC electrical signal application step (S200) frequency and impedance).

And the pressure change measuring step (S400) is made to measure the change in the physical pressure applied to the piezoelectric element based on the intrinsic resonance frequency and impedance of the piezoelectric element detected in the frequency-impedance detection step (S300).

Here, in the pressure change measuring step (S400), the intrinsic resonance frequency and impedance of the piezoelectric element change according to the change in the frequency of the AC electrical signal applied to the piezoelectric element, and this change is converted into a fine electric signal. and a signal amplification process of amplifying the signal amplitude through a signal amplifying unit in order to amplify the signal to a measurable signal level.

In addition, in the pressure change measuring step (S400), the signal output through the signal amplification process through the signal amplification unit is an AC electrical signal generated by the sine wave signal generator and electricity according to the change in the natural resonance frequency and impedance of the piezoelectric element Since the signals are mixed together, in the pressure change measuring step (S400), the AC electrical signal generated from the sine wave signal generator and output from the piezoelectric element is removed through a low pass filter provided in the intensity signal measuring device. , it is preferable to pass only the electric signal according to the change of the resonance frequency (intrinsic resonance frequency) and impedance of the pure piezoelectric element.

And the pressure change measuring step (S400), the analog electric signal according to the change of the resonance frequency and impedance of the piezoelectric element filtered through the low-pass filter and output, digital through the analog-to-digital converter provided in the intensity signal measuring device converted into a signal to be output.

In addition, the pressure change measuring step (S400) measures the change in the physical pressure applied to the piezoelectric element based on the digital signal (digital signal according to the change of the resonance frequency and impedance) of the resonance frequency and impedance of the piezoelectric element, The pressure change data is transmitted to an external upper processing device (for example, a computer or a server, etc.) through a wired/wireless communication unit provided in the intensity signal measuring device to calculate the intensity based on the pressure change data in the upper processing device. or the intensity calculated through the intensity calculator based on the pressure change data may be transmitted to an external higher-level processing device through a wired/wireless communication unit.

The pressure change measuring step ( S400 ) will be described with reference to FIGS. 2 and 3 .

2 is the resonance of the piezoelectric element according to the frequency change of the AC electrical signal applied to the piezoelectric element in a state in which no pressure is applied to the piezoelectric element in the intensity signal measuring method for monitoring the intensity of the hydration reaction material structure according to the present invention; It is a graph measuring the signal output through the low-pass filter with respect to the frequency characteristic and the impedance characteristic, and FIG. 3 is a state in which a constant pressure is applied to the piezoelectric element in the method for measuring the strength signal for monitoring the strength of the hydration reactant structure according to the present invention It is a graph measuring the signal output through the low-pass filter with respect to the resonance frequency characteristic and the impedance characteristic of the piezoelectric element according to the frequency change of the AC electrical signal applied to the piezoelectric element.

In the method for measuring the intensity signal for monitoring the intensity of the hydration reaction material structure according to the present invention, as shown in FIG. 2 , in a state in which no pressure is applied to the piezoelectric element, the frequency change of the AC electrical signal applied to the piezoelectric element As a result of measuring the signal output through a low pass filter for the resonance frequency characteristic and impedance characteristic of the piezoelectric element, it shows two distinct peak outputs with respect to a specific frequency as shown in the red circle.

And, as shown in FIG. 3, in a state where a constant pressure is applied to the piezoelectric element, the signal output through the low-pass filter is measured for the resonance frequency characteristic and impedance characteristic of the piezoelectric element according to the frequency change of the AC electrical signal applied to the piezoelectric element As a result, it shows two distinct peak outputs with respect to a specific frequency as shown in the red circle in the same state as in the state without pressure, but the frequency of the peak output changes compared to the state in which no pressure is applied.

Therefore, the pressure applied to the piezoelectric element is calculated by correlating the displacement difference of the peak frequency and the frequency characteristic of the piezoelectric element, and the intensity is measured and calculated by using the calculated pressure change data of the piezoelectric element as a measurement factor for measuring the strength. will do

Here, in order to find the peak frequency, the trend (upward linearity) of the impedance increase of the piezoelectric element according to the increase in the square wave frequency is removed through the Kalman filter, and the intensity is maximized in the profile after the trend is removed. This can be done by finding points that are (maximum) and minimum (minimum).

When the external upper processing device calculates the intensity based on the pressure change data, or transmits the intensity calculated through the intensity calculation unit based on the pressure change data to the external upper processing device through the wired/wireless communication unit, the pressure The calculation of the intensity based on the change data will be described as follows.

In a state where there is no change in intensity, the peak frequency (resonant frequency) has a constant value. When the strength of a material changes, the peak frequency (resonant frequency) value shifts, and this variation value is different for each material (material). In other words, the intensity cannot be extracted using the absolute value, and the intensity test is performed using a sample extracted from the structure at the beginning, and the park frequency (resonant frequency) at the same age is equal to the intensity value 1: 1 Correspondingly, based on the relation between the intensity value and the frequency value, the intensity according to the change in the peak frequency (resonant frequency) measured later is calculated. In other words, the strength can be measured for the same material based on a reference value.

Here, as a strength test method for a sample, a compressive strength test using a universal testing machine (UTM), a Marshall test method, a non-destructive test method using ultrasonic waves, etc. can be utilized.

On the other hand, in the intensity signal measuring method for monitoring the intensity of the hydration reaction material structure according to the present invention, when detecting the resonance frequency and impedance generated in the piezoelectric element in the frequency-impedance detection step (S300), the temperature around the impedance A correction step of minimizing the measurement error by detecting and correcting the measured resonance frequency and impedance (values of the measured resonance frequency and the measured impedance) through a temperature characteristic correction algorithm of the piezoelectric element based on the detected temperature (S500); may further include.

Specifically, the piezoelectric element has a property that the resonance frequency and impedance are slightly changed according to the temperature. The change causes a change in the resonance frequency and impedance of the piezoelectric element regardless of the pressure of the hydration heat reactant. The change in the resonance frequency and impedance of the piezoelectric element caused by such a change in the temperature of the hydration heat reactant may be mistakenly recognized as a change in the pressure of the hydration heat reactant, which may cause a measurement error in the pressure measurement of the hydration heat reactant. Therefore, the temperature sensor is positioned as close as possible to the piezoelectric element, and when measuring the resonance frequency and impedance of the piezoelectric element, the temperature around the piezoelectric element is measured and through the temperature characteristic correction algorithm of the piezoelectric element, the measured resonance By correcting the values of frequency and impedance, it is to derive the values of the corrected resonance frequency and the corrected impedance that minimize the measurement error.

More specifically, a correction method for correcting the values of the resonance frequency and impedance measured through temperature measurement will be described.

4 is a graph showing the relationship between temperature, resonant frequency, and impedance.

As shown in FIG. 4 , the change in the temperature of the hydration heat reactant according to the external temperature change causes a change in the resonance frequency and impedance of the piezoelectric element regardless of the pressure of the hydration heat reactant. Accordingly, the resonant frequency measured from the piezoelectric element is corrected together with the measured temperature in the following manner.

f = f1 + A * (Tc-Tref) + B (Equation 1)

z = z1 + C * (Tc-Tref) + B (Equation 2)

(f: corrected resonance frequency, z: corrected impedance, f1: measured resonance frequency, z1: measured impedance, A: temperature characteristic coefficient of piezoelectric element 1, C: temperature characteristic coefficient of piezoelectric element 3, B: piezoelectric element Temperature characteristic coefficient of element 2, D: temperature characteristic coefficient of piezoelectric element 4, Tc: current measured temperature, Tref: reference temperature)

A, B, C, D and Tref are different depending on the piezoelectric element used, so it can be obtained through a temperature characteristic test for the piezoelectric element.

The present invention can further correct the corrected values of the resonant frequency and impedance by further supplementing the above correction method.

An example of additional correction will be described.

The strength of a substance gradually increases according to the hydration reaction, and then converges to a constant strength at the same time as the hydration reaction is completed after a considerable period of time. In the case of general concrete, the strength can be calculated using the following empirical formula.

Strength of general concrete = 28-day strength × {21 + 61 × log (average value of curing temperature during curing period × curing period)} (Equation 3)

Therefore, in the additional correction method according to an embodiment, the correction value (the value of the correction resonance frequency and the correction impedance) obtained through the above equations 1 and 2 is supplemented using the above calculation method (Equation 3) to be additionally corrected. can

Continuing, another embodiment of the additional correction will be described.

The additional correction method according to another embodiment is a correction method according to the actual strength test result, and the correction value obtained through Equations 1 and 2 may be additionally corrected by reflecting the strength test result at a specific time point.

In addition, another embodiment of the additional correction will be described.

Figure 5 is a graph used in the calibration process of the intensity signal measurement method for monitoring the intensity of the hydration reaction material structure according to the present invention, Graph 1 is a graph in which the intensity is calculated over time in an empirical formula according to the basic frequency pattern change; Graph 2 is a graph in which the strength value at the time the strength test result comes out is confirmed as the test result value, and the strength value is calculated by accumulating the difference between {test result value - calculated value} after that point. 6 is a graph comparing graph 1 and graph 2 of FIG. 5 .

Additional correction according to another embodiment, while calculating the intensity value as shown in Graph 1, when the test result value is somewhat higher than the value calculated by the frequency as a result of performing the intensity test 24 hours after the start of curing , obtained through Equations 1 and 2 above by determining the strength test result value as the strength value at 24 hours after the start of curing, and adding the difference as much as {test result value - calculated value} to the strength calculation thereafter The correction value can be further corrected.

Next, the intensity signal measuring apparatus for monitoring the intensity of the hydration reactant structure according to the present invention will be described in detail with reference to FIGS. 7 and 8 .

7 is a block diagram schematically showing the configuration of a strength signal measuring apparatus for monitoring the strength of a hydration reactant structure according to the present invention, and FIG. 8 is a strength signal for monitoring the strength of a hydration reaction material structure according to the present invention. It is a block diagram schematically showing the configuration of the control module unit constituting the measurement device in blocks.

The intensity signal measuring device for monitoring the strength of the hydration reaction material structure according to the present invention is installed in a structure made of a hydration reaction material (for example, a concrete structure constructed by pouring ready-mixed concrete or a ground improved by a method such as DCM) As an intensity signal measuring device connected to the piezoelectric element to generate and measure an intensity signal for measuring the intensity of the hydration reactant structure, as shown in FIGS. 7 and 8, the device housing 100; AC electrical signal generator 200; control module unit 300; and a power supply unit 400 .

Specifically, the strength signal measuring device for monitoring the strength of the hydration reaction material structure according to the present invention is a structure made of a hydration reaction material (for example, a concrete structure constructed by pouring ready-mixed concrete or a ground improved by a method such as DCM) ) as an intensity signal measuring device connected to the piezoelectric element installed to generate and measure an intensity signal for measuring the strength of the hydration reaction material structure, and as shown in FIGS. 7 and 8, a connection port electrically connected to the piezoelectric element or a device housing 100 configured with a connection portion of a connection cable; an AC electrical signal generator 200 provided in the device housing 100 and configured to generate an AC electrical signal of a specific waveform having a frequency of a predetermined frequency band; It is provided in the device housing 100, and the AC electrical signal generator 200 controls to generate an AC electrical signal of a specific waveform having a frequency of a predetermined frequency band, and applies the generated AC electrical signal to the piezoelectric element, , a control module unit 300 for measuring a change in physical pressure applied to the piezoelectric element based on the AC electrical signal applied to the piezoelectric element; and a power supply unit 400 provided in the device housing 100 and configured to supply necessary power to the control module unit 300 .

The device housing 100 is made so that the above-described components are mounted therein, has a handle for portability and portability, and can be manufactured in a small size, and is partially opened or closed or divided for maintenance of internal components. can be configured.

The AC electrical signal generator 200 can generate an AC electrical signal of a specific waveform having a frequency of a predetermined frequency band, that is, an AC electrical signal in the form of a sine wave having a frequency band of a low frequency to a high frequency. It consists of a sine wave signal generator capable of sequentially generating within a predetermined time.

Next, the control module unit 300 controls the AC electrical signal generator 200 to generate an AC electrical signal of a specific waveform having a frequency of a predetermined frequency band, and applies the generated AC electrical signal to the piezoelectric element. is applied, and is made to measure the change in physical pressure applied to the piezoelectric element based on the AC electrical signal applied to the piezoelectric element. It includes a detection unit 320 and a pressure change measurement unit 330 .

Specifically, as shown in FIG. 5 , the control module unit 300 controls the AC electrical signal generator 200 so that an AC electrical signal of a predetermined frequency (frequency band) and generation time is applied to the piezoelectric element. an AC electrical signal control unit 310, and a frequency-impedance detection unit 320 for detecting a change in the resonant frequency (intrinsic resonance frequency) and impedance of the piezoelectric element according to the frequency of the AC electric signal applied to the piezoelectric element-impedance detection unit 320, and the The frequency-impedance detector 320 includes a pressure change measuring unit 330 that measures a change in physical pressure applied to the piezoelectric element based on the change in the resonance frequency and impedance of the piezoelectric element.

The frequency and the generation time of the AC electrical signal generator controlled by the AC electrical signal controller 310 of the control module 300 are determined according to the frequency characteristics of the piezoelectric element. For example, the AC electrical signal control unit 310 may control the AC electrical signal generator 200 to generate a sine wave of 5 KHz to 100 KHz for 1 second.

The frequency-impedance detection unit 320 is configured to detect a change in the intrinsic resonance frequency and impedance generated in the piezoelectric element by the frequency of the AC electrical signal controlled by the AC electrical signal control unit 310 .

And the pressure change measuring unit 330 is configured to measure a change in the physical pressure applied to the piezoelectric element based on the change in the resonance frequency and impedance of the piezoelectric element detected by the frequency-impedance detector 320 .

Here, the pressure change measuring unit 330 changes the resonance frequency and impedance of the piezoelectric element according to the change in the frequency of the AC electrical signal applied to the piezoelectric element, and this change is converted into a fine electric signal, the present invention It may further include a component for amplifying the fine electric signal.

More specifically, the control module unit 300 of the intensity signal measuring apparatus for monitoring the intensity of the hydration reaction material structure according to the present invention is for amplifying the magnitude of the electric signal according to the change in the resonance frequency and impedance of the piezoelectric element. A signal amplifier 340 may be further included.

In addition, since the signal output through the signal amplification process through the signal amplification unit 340 is mixed with the AC electrical signal generated by the AC electrical signal generator 200 and the electrical signal according to the resonance frequency and impedance change of the piezoelectric element, , It may further include a component for removing the AC electrical signal generated by the AC electrical signal generating unit 200, and passing only the electrical signal according to the change in the resonance frequency and impedance of the piezoelectric element.

Specifically, the control module unit 300 of the apparatus for measuring the strength signal for monitoring the strength of the hydration reactant structure according to the present invention removes the AC electrical signal generated by the AC electrical signal generating unit 200, and the piezoelectric element It may further include a low pass filter part (Low PassFilter part) 350 made to pass only the electrical signal according to the resonance frequency and impedance change of the.

Since the measurement of the pressure change by the pressure change measuring unit 330 has been previously described with reference to FIGS. 2 and 3 , a description thereof will be omitted for the sake of simplicity.

Subsequently, the control module unit 300 of the apparatus for measuring the strength signal for monitoring the strength of the hydration reactant structure according to the present invention changes the resonance frequency and impedance of the piezoelectric element filtered through the low-pass filter unit 350 and output. It may further include an analog-to-digital converter unit 360 configured to convert an analog electrical signal according to a digital signal and output it.

On the other hand, the intensity signal measuring apparatus for monitoring the strength of the hydration reaction material structure according to the present invention is pressure change data obtained by measuring the change in physical pressure applied to the piezoelectric element based on the digital signal of the resonance frequency and impedance change of the piezoelectric element. It may further include a wired/wireless communication module unit 500 configured to transmit to an external higher-level processing device (eg, a computer or a server). At this time, the upper-level processing device derives the intensity based on the received pressure change data.

Here, the control module unit 300 of the apparatus for measuring the intensity signal for monitoring the intensity of the hydration reactant structure according to the present invention is a physical pressure applied to the piezoelectric element based on the digital signal of the resonance frequency and impedance change of the piezoelectric element. Further comprising a strength calculation unit 370 for calculating and calculating the strength based on the pressure change data measured the change of, the strength data calculated by the strength calculation unit 370 is the wire/wireless communication module unit 500 It may be configured to be transmitted to an external upper processing device through the Here, the present invention is provided in the device housing 100 in order to display the intensity data calculated by the intensity calculation unit 370 , is connected to the control module unit 300 , and is used in the strength calculation unit 370 . The display unit 600 for displaying the calculated intensity data; may further include.

The intensity calculation in the upper-level processing device or the intensity calculation in the intensity calculation unit 370 of the control module unit 300 will be described as follows.

In a state where there is no change in intensity, the peak frequency (resonant frequency) has a constant value. When the strength of a material changes, the peak frequency (resonant frequency) value shifts, and this variation value is different for each material (material). In other words, the intensity cannot be extracted using the absolute value, and the intensity test is performed using a sample extracted from the structure at the beginning, and the park frequency (resonant frequency) at the same age is equal to the intensity value 1: 1 Correspondingly, based on the relation between the intensity value and the frequency value, the intensity according to the change in the peak frequency (resonant frequency) measured later is calculated. In other words, the strength can be measured for the same material based on a reference value. Here, as a strength test method for a sample, a compressive strength test using a universal testing machine (UTM), a Marshall test method, a non-destructive test method using ultrasonic waves, etc. can be utilized.

Next, the power supply unit 400 may be configured as a replaceable battery or a rechargeable battery.

In addition, the strength signal measuring apparatus for monitoring the strength of the hydration reactant structure according to the present invention is a GPS configured to transmit location information of a measurement point or construction location information to a higher processing device through the wired/wireless communication module unit 500 . The module unit 700; may further include.

On the other hand, the intensity signal measuring device for monitoring the intensity of the hydration reactant structure according to the present invention is a temperature sensor 800 installed on the lower surface of the device housing 100 to detect the ambient temperature of the impedance, and the When the frequency-impedance detection unit 320 detects the resonance frequency and impedance of the piezoelectric element, the temperature characteristic of the piezoelectric element is corrected based on the temperature detected by the temperature sensor 800 . The frequency-impedance correction unit 380 for minimizing the measurement error by correcting the resonant frequency and impedance values measured through the algorithm; may further include.

The frequency-impedance corrector 380 may obtain a corrected resonant frequency and a corrected impedance through Equations 1 and 2 below.

f = f1 + A * (Tc-Tref) + B (Equation 1)

z = z1 + C * (Tc-Tref) + B (Equation 2)

(f: corrected resonance frequency, z: corrected impedance, f1: measured resonance frequency, z1: measured impedance, A: temperature characteristic coefficient of piezoelectric element 1, C: temperature characteristic coefficient of piezoelectric element 3, B: piezoelectric element Temperature characteristic coefficient of element 2, D: temperature characteristic coefficient of piezoelectric element 4, Tc: current measured temperature, Tref: reference temperature)

A, B, C, D, and Tref are constant values obtained through a temperature characteristic experiment on the piezoelectric element because it is different depending on the piezoelectric element used.

This correction of the resonance frequency and impedance is based on the fact that the change in the temperature of the hydration heat reactant according to the external temperature change causes the change in the resonance frequency and impedance of the piezoelectric element regardless of the pressure of the hydration heat reactant.

In addition, the above-described resonant frequency and impedance correction may be supplemented by the additional correction described above.

According to the intensity signal measuring method and intensity signal measuring apparatus for monitoring the intensity of the hydration reaction material structure according to the present invention as described above, the strength of the structure is reliably measured and continuous monitoring is provided using the impedance characteristic of the piezoelectric element. This can be done and can be manufactured in a small size, so portability and portability can be secured, and accordingly, there is an advantage that strength can be easily measured regardless of location.

The embodiments described in this specification and the accompanying drawings are merely illustrative of some of the technical ideas included in the present invention. Accordingly, since the embodiments disclosed in the present specification are for explanation rather than limitation of the technical spirit of the present invention, it is obvious that the scope of the technical spirit of the present invention is not limited by these embodiments. Modifications and specific embodiments that can be easily inferred by those skilled in the art within the scope of the technical spirit included in the specification and drawings of the present invention should be interpreted as being included in the scope of the present invention.

Explanation of signs

S100: AC electrical signal generation step

S200: AC electrical signal application step

S300: frequency-impedance detection stage

S400: pressure change measurement step

S500: Calibration step

100: device housing

200: AC electrical signal generator

300: control module unit

310: AC electrical signal control unit

320: frequency-impedance detection unit

330: pressure change measuring unit

340: signal amplification unit

350: low-pass filter unit

360: analog-digital converter unit

370: strength calculator

380: frequency-impedance correction unit

400: power unit

500: wired and wireless communication module unit

600: display unit

700: GPS module unit

800: temperature sensor

Claims (10)

1. A method for measuring the strength of a hydration reaction material structure through an intensity signal measuring device that is connected to a piezoelectric element installed in a structure made of a hydration reaction material and generates and measures an intensity signal for measuring the strength of the hydration reaction material structure,

   AC electrical signal generating step of generating an AC electrical signal of a specific waveform having a frequency of a predetermined frequency band;

   an AC electrical signal applying step of applying the generated AC electrical signal to the piezoelectric element for a predetermined time;

   a frequency-impedance detection step of detecting a change in the resonance frequency and impedance of the piezoelectric element according to the frequency of the AC electrical signal applied in the AC electrical signal application step; and

   and a pressure change measuring step of measuring a change in physical pressure applied to the piezoelectric element as an intensity signal based on the detected change in resonance frequency and impedance of the piezoelectric element.

   A method of measuring an intensity signal for monitoring the intensity of a hydration reactant structure.
2. According to claim 1,

   The step of generating the AC electrical signal consists of sequentially generating an AC electrical signal in the form of a sine wave having a predetermined frequency band for a predetermined time,

   The frequency band and the generation time of the AC electrical signal are determined according to the frequency characteristics of the piezoelectric element.

   A method for measuring intensity signals for monitoring the intensity of the hydration reactant structure.
3. According to claim 1,

   The pressure change detection step is configured to detect the amplified electrical signal after amplifying the electrical signal according to the change in the resonance frequency and impedance of the piezoelectric element according to the frequency of the AC electrical signal,

   In the pressure change measuring step, the AC electrical signal generated by the AC electrical signal generating unit is removed through a low-pass filter, and only the electrical signal according to the change in the resonance frequency and impedance of the piezoelectric element is passed to measure the electrical signal characterized by

   A method of measuring an intensity signal for monitoring the intensity of a hydration reactant structure.
4. According to claim 1,

   In the frequency-impedance detection step, when the resonance frequency and impedance generated in the piezoelectric element are detected, a correction step of detecting the temperature around the impedance and correcting the measured resonance frequency and impedance to minimize the measurement error; further comprising,

   In the correction step, the resonant frequency and the corrected impedance are obtained through Equations 1 and 2 below.

   f = f1 + A * (Tc-Tref) + B (Equation 1)

   z = z1 + C * (Tc-Tref) + B (Equation 2)

   (here, f: corrected resonance frequency, z: corrected impedance, f1: measured resonance frequency, z1: measured impedance, A: temperature characteristic coefficient of piezoelectric element 1, C: temperature characteristic coefficient of piezoelectric element 3, B: temperature characteristic coefficient of piezoelectric element 2, D: temperature characteristic coefficient of piezoelectric element 4, Tc: measured current temperature, Tref: reference temperature, A, B, C, D and Tref are temperature characteristic tests for piezoelectric element constant value obtained through

   A method of measuring an intensity signal for monitoring the intensity of a hydration reactant structure.
5. An intensity signal measuring device connected to a piezoelectric element installed in a structure made of a hydration reaction material to generate and measure an intensity signal for measuring the strength of a hydration reaction material structure,

   an apparatus housing configured with a connection portion electrically connected to the control module portion to a piezoelectric element;

   an AC electrical signal generator provided in the device housing and configured to generate an AC electrical signal of a specific waveform having a frequency of a predetermined frequency band;

   It is provided in the device housing, and the AC electrical signal generator controls so that an AC electrical signal of a specific waveform having a frequency of a predetermined frequency band is generated, and applies the generated AC electrical signal to the piezoelectric element, and is applied to the piezoelectric element a control module unit for measuring a change in physical pressure applied to the piezoelectric element based on the obtained AC electrical signal; and

   and a power supply unit provided in the device housing and configured to supply necessary power to the control module unit.

   Intensity signal measuring device for monitoring the strength of the hydration reactant structure.
6. 6. The method of claim 5,

   The AC electrical signal generator consists of a sine wave signal generator that generates an AC electrical signal of a sine wave having a predetermined frequency band,

   The control module unit includes an AC electrical signal control unit that controls the AC electrical signal generated by the sine wave signal generator to be applied to the piezoelectric element, and a resonance frequency of the piezoelectric element according to the frequency of the AC electrical signal applied to the piezoelectric element; Frequency-impedance detection unit for detecting a change in impedance, and a pressure change measuring unit for measuring a change in physical pressure applied to the piezoelectric element based on the change in the resonance frequency and impedance of the piezoelectric element detected by the frequency-impedance detection unit characterized by

   Intensity signal measuring device for monitoring the strength of the hydration reactant structure.
7. 7. The method of claim 6,

   The control module unit,

   a signal amplifying unit for amplifying a magnitude of an electric signal according to a change in a resonance frequency and an impedance of the piezoelectric element;

   a low-pass filter unit configured to remove an AC electrical signal generated by the AC electrical signal generator among the electrical signals outputted from the signal amplifying unit, and to pass only an electrical signal according to a change in the resonance frequency and impedance of the piezoelectric element; and

   An analog-to-digital converter unit configured to convert and output an analog electric signal according to a change in the resonance frequency and impedance of the piezoelectric element filtered through the low-pass filter unit and outputted into a digital signal; characterized in that it further comprises

   Intensity signal measuring device for monitoring the strength of the hydration reactant structure.
8. 8. The method of claim 7,

   a wired/wireless communication module unit provided in the device housing to transmit pressure change data measuring a change in physical pressure applied to the piezoelectric element based on a digital signal of a resonant frequency and impedance change of the piezoelectric element to an external upper processing device; and

   A GPS module provided in the device housing and configured to transmit the location information of the piezoelectric element to an external higher-level processing device; characterized in that it further comprises

   Intensity signal measuring device for monitoring the strength of the hydration reactant structure.
9. 8. The method of claim 7,

   The control module unit further includes a strength calculator that calculates and calculates the strength based on the pressure change data that measures the change in the physical pressure applied to the piezoelectric element based on the digital signal of the resonance frequency and impedance change of the piezoelectric element,

   The apparatus for measuring the intensity signal includes a wired/wireless communication module configured to transmit the intensity data calculated by the intensity calculator to an external higher-level processing device, a display unit for displaying the intensity data calculated by the intensity calculator, and the A GPS module unit provided in the device housing and configured to transmit the location information of the piezoelectric element to an external higher-level processing device; characterized by further comprising:

   Intensity signal measuring device for monitoring the strength of the hydration reactant structure.
10. 7. The method of claim 6,

    A temperature sensor installed on the lower end surface of the device housing to detect an ambient temperature of impedance, and the control module unit, the frequency-impedance detecting unit detects the resonance frequency and impedance of the piezoelectric element, the temperature sensor It further includes; a frequency-impedance correcting unit that minimizes the measurement error by correcting the measured resonance frequency and impedance value based on the temperature detected by the

    The frequency-impedance correcting unit, characterized in that it obtains the corrected resonant frequency and the corrected impedance through Equations 1 and 2 below.

    f = f1 + A * (Tc-Tref) + B (Equation 1)

    z = z1 + C * (Tc-Tref) + B (Equation 2)

    (here, f: corrected resonance frequency, z: corrected impedance, f1: measured resonance frequency, z1: measured impedance, A: temperature characteristic coefficient of piezoelectric element 1, C: temperature characteristic coefficient of piezoelectric element 3, B: temperature characteristic coefficient of piezoelectric element 2, D: temperature characteristic coefficient of piezoelectric element 4, Tc: measured current temperature, Tref: reference temperature, A, B, C, D and Tref are temperature characteristic tests for piezoelectric element constant value obtained through

    Intensity signal measuring device for monitoring the strength of the hydration reactant structure.

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