TWI612302B - Method for judging fire damage of cement matrix structure - Google Patents

Description

Method for judging fire damage of cement matrix structure

The invention relates to a fire damage discrimination method for a concrete structure, in particular to the rapid preliminary identification of a fire concrete structure by using integrated acoustic measurement, ultrasonic pulse and sound injection.

"Life" and "safety" are the primary pursuits of mankind. To protect people's lives and property from fire hazards, the fire resistance of buildings plays a very important role. Therefore, the industry and the academic community are committed to development. Mechanisms and software, hardware, in order to achieve the ability to perform on-site and correctly assess the damage of the building structure (including underground structure) caused by fire.

In the conventional technology, non-destructive acoustic detection technology has been widely used in different detection fields, in which the development of the United States and Japan is superior, including the AE Rate from the early solution of the unknown number as the force. After the microcrack test, the confirmation of the microcrack coordinate position (unknown number is 4), and the estimate from the late to the latest source characterization (unknown number is 6), can be displaced by the crack Orientation of Displacement Discontinuity to identify the mode of failure of microcracks.

Specifically, in recent years, acoustic technology has been applied to detect defects in materials and internal aging damage, etc., and after being subjected to forces, electromagnetics, temperature changes, etc., the materials accumulate energy inside, when they can withstand At the limit, the energy is released in the form of micro-cracks, which form a significant giant crack when the micro-cracks are concentrated. When the building structure is damaged by fire, it will produce micro-cracks or giant cracks inside, greatly reduce the mechanical strength, and even form dangerous structures. It must be removed immediately to prevent collapse. Therefore, acoustic technology can judge the degree of internal damage of the building structure.

However, traditional practice must first sample the building structure after the fire and conduct the strength test in the laboratory to obtain the correct data. Therefore, the above conventional technology The disadvantage is that the relevant test instruments and equipment cannot directly detect the building structure at the scene of the fire, and the overall processing procedure is quite time consuming, laborious and inefficient.

Therefore, there is a need for a new type of fire damage determination method for cement matrix structures. Passive acoustic technology and active ultrasonic pulse flaw detection technology can be used to discriminate the damage degree of concrete structures after fire damage without destroying the composition. The cement matrix material of the concrete structure can realize the non-destructive rapid detection and discrimination function, thereby solving the problems of the above-mentioned conventional technology.

The main object of the present invention is to provide a method for judging the fire damage of a cement matrix structure, which is used for discriminating the degree of fire damage of a cement matrix material constituting a cement matrix structure, mainly including: using sound with a sound pulse measuring function The pulse measuring unit is configured to measure the strength loss and the microseismic source distribution data of the standard sample of the cement matrix material under the gradual increase of the external pressure applied by at least one uniaxial compression testing machine, and the standard sample has a known fire damage At the same time, an ultrasonic pulse measuring device with ultrasonic pulse measuring function is used to project and receive ultrasonic pulses on a standard sample, thereby measuring the multiple wave velocity data of the standard sample in the damage process (loading history), and the wave velocity thereof. The data includes pressure wave velocity, shear wave velocity and shear-pressure wave velocity ratio, and the multi-wave velocity data corresponds to the intensity loss and microseismic source distribution data obtained by the acoustic pulse measuring unit; combined strength loss and microseismic source distribution Data and multiple wave velocity data to establish a fire damage database corresponding to the standard sample; reuse the ultrasonic pulse measuring device Velocity data measured cementitious matrix material sample to be tested; the use of velocity information and the reference test sample library fire damage, thereby discriminating damage degree of fire sample to be tested.

Specifically, the standard sample generates at least one micro-crack under different stress loading history, and generates transient elastic stress waves from the micro-cracks, and simultaneously propagates outward as an acoustic signal, and the acoustic pulse is measured. The unit uses the sound pulse measurement function to measure the sound signal, and generates a sensing signal, and then uses the arrival time positioning method to obtain the position of the micro crack, thereby generating the microseismic source distribution data of the standard sample, and adding the data according to the addition. The strength of the standard sample is obtained by pressure.

Therefore, the method of the present invention actually uses passive acoustic technology and active super The sonic pulse flaw detection technology can be used to discriminate the damage degree of the concrete structure after the fire damage, and does not destroy the cement matrix material constituting the concrete structure, thereby realizing the non-destructive detection function, especially the acoustic material can be used to detect the cement matrix. The degree of internal deep damage in the material, such as micro-cracks, is not limited to the damage of the surface appearance, so it can quickly provide a judgment on the overall structural strength change of the cement matrix material, and determine the degree of damage to the site fire damage. The material damage evolution before and after the fire damage can improve the effect of material fire safety and the participation of future engineering fire damage assessment.

S10~S50‧‧‧Steps

10‧‧‧Acoustic pulse measuring unit

20‧‧‧ Ultrasonic Pulse Measurer

AES‧‧ ‧ Sound Sensor

CBM‧‧‧cement matrix material

FU‧‧‧Sound Signal Acquisition Unit

MCK‧‧‧ micro crack

MEM‧‧‧ memory unit

P‧‧‧External pressure

PAMP‧‧‧ preamplifier

PAMPU‧‧‧ preamplifier unit

UPTM‧‧‧ Single Axis Compression Tester

PU‧‧‧Data Processing Unit

TESW‧‧‧Transient Elastic Stress Wave

UC1‧‧‧First Ultrasonic Probe

UC2‧‧‧Second Ultrasonic Probe

The first figure is a schematic diagram of the operation flow of the method for judging the fire damage of the cement matrix structure according to the embodiment of the present invention.

The second figure is a schematic diagram of the measurement of micro-cracks and transient elastic stress waves and wave velocity data in the fire damage discrimination method of the present invention.

The third figure is a schematic diagram of the sensing signals generated by the sounding sensor in the method for judging the fire damage of the present invention.

The fourth figure is a schematic diagram of the arrival time positioning method in the fire damage discrimination method of the present invention.

The embodiments of the present invention will be described in more detail below with reference to the drawings and the reference numerals, which can be implemented by those skilled in the art after having studied this specification.

Please refer to the first figure, a schematic diagram of the operation flow of the method for judging the fire damage of the cement matrix structure according to the embodiment of the present invention. As shown in the first figure, the method for judging the fire damage of the cement matrix structure of the present invention mainly includes steps S10, S20, S30, S40 and S50 for discriminating the degree of fire damage of the cement matrix material constituting the cement matrix structure.

In order to clearly illustrate the technical features of the present invention, please also refer to the second figure, and measure the micro-crack and transient elastic stress wave and wave velocity data.

First, the method for judging the acoustic damage of the cement matrix structure of the present invention is started simultaneously by steps S10 and S20, and step S10 uses the acoustic pulse measuring unit 10 as shown in the second figure. The strength loss and the microseismic source distribution data of the standard sample of the cement matrix material CBM are measured, wherein the standard sample has a known degree of fire damage, and the acoustic pulse measuring unit 10 has an acoustic pulse measurement function, and the cement matrix material The CBM is subjected to at least one uniaxial compression tester UPTM applying a stepwise increase in external pressure p. Since the standard sample generates at least one micro-crack MCK under different stress loading history, the micro-crack MCK simultaneously generates a transient elastic stress wave TESW, which is used as an acoustic signal and propagates outward. The sounding pulse measuring unit 10 can measure the sounding signal to generate the sensing signal, and obtain the position of each microcrack MCK by the arrival time localization method, thereby generating the microseismic crack source distribution data of the standard sample, wherein the microseismic crack The source distribution data represents the internal and external destructive characteristics of the standard sample of the cement matrix material CBM. At the same time, the strength loss of the standard sample can be obtained according to the applied pressure P of the standard sample at the time of generating the microcrack MCK.

Step S20 uses the ultrasonic pulse measurer 20 as shown in the second figure to project and receive an ultrasonic pulse on the standard sample, thereby measuring the multiple wave velocity data of the standard sample in the damage process, wherein the wave velocity The data includes the Velocity of Primary Wave, the Velocity of Secondary Wave, and the shear-to-pressure velocity ratio. The ultrasonic pulse measuring device 20 of the present invention has an ultrasonic pulse measuring function, and the wave velocity data corresponds to the intensity impairment and the microseismic source distribution data obtained by the acoustic pulse measuring unit 10.

Then, in step S30, by combining the intensity impairment obtained in step S10, the microseismic source distribution data, and the plurality of wave velocity data obtained in step S20, a fire damage database corresponding to the standard sample is established. Specifically, the fire damage database is stored in the portable memory unit MEM, and the memory unit MEM is used to electrically connect to the ultrasonic pulse measurer 20, as shown in the second figure, or the memory unit MEM It can also be included in the ultrasonic pulse measure to be integrated (not shown).

In step S40, the wave velocity data of the sample to be tested of the cement matrix material CBM is measured using the ultrasonic pulse measurer 20 as shown in the second figure. Finally, step S50 is performed to determine the fire damage degree of the sample to be tested of the cement matrix material CBM by using the wave velocity data of the sample to be tested obtained in step S40 and referring to the fire damage database obtained in step S30.

More specifically, the above-described acoustic pulse measuring unit 10 may include at least five sounding sensor AES, a preamplifier unit PAMPU, an acoustic signal extracting unit FU, and data. Processing unit PU. Each sound sensor AES is attached to the sample to be tested, and the transient elastic stress wave TESW can be sensed to generate a sensing signal to be used as an acoustic event. The preamplifier unit PAMPU includes at least five preamplifiers PAMP, wherein each preamplifier PAMP is connected to the corresponding acoustic sensor AES by a signal line for receiving the sensing signal and amplifying the sensing signal and Filtering produces a amplified sensing signal. The sounding signal acquisition unit FU receives the amplified sensing signal at a preset capturing frequency and determines whether a sounding event is recorded.

In addition, the data processing unit PU receives the amplified sensing signal of the acoustic signal extraction unit FU, and finds the individual time of the transient elastic stress wave TESW of the micro-crack MCK reaching each acoustic sensor AES, using the arrival time positioning method. (Arrival time difference method), such as the three-dimensional positioning method of the time difference, to obtain the position of the micro-crack MCK, and then to map the micro-crack source according to the position of the micro-crack MCK. Further, the time-of-arrival method can obtain the time difference of the ultrasonic pulse to the AES, and then use the statistical residual method to obtain the micro-crack source position of the micro-crack MCK of the standard sample of the cement matrix material to the acoustic emission sensor CBM. (Micro seismic source), in which microcracks MCK at different locations have different arrival times.

In addition, the acoustic sensor AES can be a piezoelectric transducer and is adhered to a standard sample of the cement matrix material CBM using a glue.

Furthermore, regarding the sensing signal generated by the sounding sensor AES, reference may be made to the third figure, which is a schematic diagram of the sensing signal generated by the sounding sensor in the fire damage determining method of the present invention, wherein the data processing unit PU is When the sensing signal exceeds the threshold, it will be regarded as a valid sounding event. At this time, the sensing signal is available for the arrival time positioning method to obtain the position of the microseismic source, and therefore, below the threshold value. The sensing signal is regarded as an invalid signal by the present invention and does not perform any processing.

Furthermore, the arrival time positioning method in the fire damage discrimination method of the present invention can refer to the fourth figure. Since the arrival time positioning method is a general conventional technology and is not the core technical content of the present invention, it will not be described in detail herein.

Regarding the ultrasonic pulse measurement of step S20, the ultrasonic pulse measurer 20 is mainly a portable device, and can be configured to be electrically connected to the first ultrasonic probe UC1 and the second ultrasonic probe UC2, wherein the first super The sonic probe UC1 and the second ultrasonic probe UC2 are in different positions on the surface contacting the cement matrix material CBM. Therefore, the ultrasonic pulse measuring device 20 A stress wave capable of generating an ultrasonic pulse pattern is projected onto the cement matrix material CBM via the first ultrasonic probe UC1, and the ultrasonic pulse propagated by the cement matrix material CBM is received by the second ultrasonic probe UC2, and then transmitted to the super The sonic pulse measuring device 20 is used to obtain the pressure wave velocity, the shear wave velocity and the shear-pressure wave velocity ratio of the cement matrix material CBM, and is used as a plurality of wave velocity data.

Therefore, the fire damage discrimination method of the present invention is a highly integrated technology combining passive acoustic technology and active ultrasonic pulse flaw detection technology.

In summary, the main feature of the present invention is the use of passive acoustic technology and active ultrasonic pulse flaw detection technology to discriminate the degree of damage of the cement matrix material after fire damage, and does not destroy the cement matrix material after the fire damage. Therefore, the non-destructive detection function is specifically implemented. In particular, acoustic techniques can be used to detect damage to internal deep layers in cement matrix materials, such as micro-cracks, rather than being limited to damage to the surface appearance, thus providing a quick indication of the overall structural strength variation of the cement matrix material.

In addition, the present invention can also utilize the main-passive giant-micro synchronous coupling acoustic technology and the ultrasonic pulse flaw detection measurement technology to perform the complete loading history curve corresponding to the giant-micro crack location and deformation of the uniaxial compression test before and after the fire damage. The Displacement Continuity (DC) and Displacement Discontinuity (DD) of the field development provide a burst-type acoustic event generated by the internal industry using passive acoustic technology and time difference positioning method to locate and analyze the cracking of the material. Furthermore, the "inside and outside" fracture characteristics of the cement matrix material before and after the fire damage can be observed, such as the stiffness, strength, toughness and microscopic clustering, initial cracking, cracking, and the degree of damage. The link is used as a giant-microscopic fire damage feature built by the database in the future. In addition, in the field, the shear-pressure wave ratio of the active ultrasonic pulse detection measurement technology can be used to detect the damage of the material. Therefore, the present invention has the advantages that the ultrasonic waves V _P , V _S , V _s /V _p can be quickly measured at the scene of the fire damage, and the correlation of the aforementioned giant-micro database can be simultaneously established. The data collected by the field shall verify the correctness of the shear-pressure wave velocity ratio V _s /V _p , and determine the degree of damage caused by fire damage in the future, and understand the material damage evolution before and after the fire damage, so as to improve the fire safety of materials. The effect of research and judgment and the future project fire damage assessment.

The above is only a preferred embodiment for explaining the present invention, and is not intended to limit the present invention in any way, and any modifications or alterations to the present invention made in the spirit of the same invention. All should still be included in the scope of the intention of the present invention.

S10~S50‧‧‧Steps

Claims (7)

A method for judging the fire damage of a cement matrix structure is used for discriminating the degree of fire damage of a cement matrix material constituting a cement matrix structure, comprising: using an acoustic pulse measuring unit with an acoustic pulse measuring function And a method for measuring a strength loss and a microseismic source distribution of a standard sample of the cement matrix material under an external pressure applied by at least one uniaxial compression tester, and the standard sample has a known The degree of fire damage; at the same time, using an ultrasonic pulse measuring device, with ultrasonic pulse measuring function, projecting and receiving an ultrasonic pulse on the standard sample, thereby measuring the complex wave velocity data of the standard sample, And the plurality of wave velocity data includes a Velocity of Primary Wave, a Velocity of Secondary Wave, and a shear-pressure wave velocity ratio, and the complex wave velocity data corresponds to using the acoustic pulse measuring unit Obtaining the intensity impairment and the microseismic source distribution data; combining the intensity impairment, the microseismic source distribution data, and the complex wave velocity data to construct Establishing a fire damage database corresponding to the standard sample; using the ultrasonic pulse measuring device to measure the wave velocity data of a sample to be tested of the cement matrix material; using the wave velocity data of the sample to be tested and referring to the fire damage a database for discriminating the degree of fire damage of the sample to be tested, wherein the standard sample is a transient elastic stress wave which generates at least one micro-crack under different stress loading history and the at least one micro-crack generates and propagates (Transient elastic stress wave), which is used as a sound signal, and the sound pulse measuring unit uses the sound pulse measuring function. Measuring the sounding signal to generate a sensing signal, and obtaining a position of the at least one microcrack by an arrival time positioning method, thereby generating a microseismic source distribution data of the standard sample, and obtaining the pressure according to the applied pressure The strength of the standard sample is degraded. According to the fire damage discrimination method of claim 1, wherein the microseismic source distribution data represents internal and external damage characteristics of the standard sample of the cement matrix material. According to the fire damage discriminating method of claim 1, wherein the sounding pulse measuring unit comprises: at least five sounding sensors for sensing the transient elastic stress wave, generating the sensing signal to The sounding event; a preamplifier unit comprising at least five preamplifiers, each preamplifier being electrically connected to a corresponding acoustic sensor for receiving the sensing signal and sensing the same The signal is amplified and filtered to generate a amplified sensing signal; a sound signal capturing unit receives the amplified sensing signal at a preset frequency and determines whether the sounding event is recorded; and a data processing The unit is configured to receive the amplified sensing signal of the sound signal capturing unit, and find an individual time when the transient elastic stress wave of the micro crack reaches each sounding sensor, and use the arrival time positioning method to obtain The position of the microcrack is used to map the microseismic source according to the position of the microcrack. According to the method for determining the fire damage according to item 3 of the patent application scope, wherein the sounding sensor is a pressure A piezoelectric transducer, and the acoustic sensor is adhered to the cement matrix material by means of a glue. According to the fire damage discrimination method of claim 3, wherein the data processing unit performs the arrival time positioning method to obtain the position of the at least one micro crack when the sensing signal exceeds a threshold. . According to the fire damage discrimination method of claim 1, wherein the ultrasonic pulse measuring device is a portable device configured to be electrically connected to a first ultrasonic probe and a second ultrasonic probe, and The first ultrasonic probe and the second ultrasonic probe contact different positions on a surface of the cement matrix material, and the ultrasonic pulse measuring device generates a stress wave of the ultrasonic pulse pattern, and the first ultrasonic probe is used Projecting to the cement matrix material, and receiving, by the second ultrasonic probe, an ultrasonic pulse propagated through the cement matrix material, and transmitting the ultrasonic pulse to the ultrasonic pulse measuring device to obtain the pressure wave velocity, the shear wave velocity, and the Shear-pressure wave speed ratio. According to the fire damage discrimination method of claim 1, wherein the fire damage database is stored in a portable memory unit, and the memory unit is electrically connected to the ultrasonic pulse measuring device, or The memory unit is included in the ultrasonic pulse measurer.