Concrete Steel Reinforcement Corrode Monitoring Device
Technical field:
The utility model belongs to the surveying instrument of test and analysis of material decay resistance and corrosion speed, and parameters such as especially a kind of polarization resistance by the measurement corrosion system, Tafel slope realize Concrete Steel Reinforcement Corrode Monitoring Device.
Technical background:
In reinforced concrete structure, reinforcing bar is main stressed material.Generally speaking, reinforcing bar is passive state in concrete high alkalinity environment, do not corroded.But along with factors such as building substance aging and environmental pollution increase the weight of cause steel bar corrosion, will influence structure bearing capacity, when serious even cause structural failure, and the corrosion detection/monitoring of reinforcing bar can provide basic data for the surplus load and the durability of structures of reinforced concrete structure.Therefore, the corrosion detection/monitoring of reinforced concrete has important social meaning and economic benefit.
Corrosion detection/the monitoring method of reinforcing bar is more in the relevant concrete, and wherein observation method of naked eye and sampling method are the classic methods of using always, but exists significant limitation.Show: (1) relies on the naked eyes visual examination and combines with the physical chemistry test, and is often late when pinpointing the problems like this; (2) sampling selective examination method is limited because of quantity of sampling quantity, can not reflect whole concrete structure erosion situation, and xoncrete structure is had in various degree damage.Because the corrosion of reinforcing bar is an electrochemical process in the concrete, therefore, can obtain very big attention and development to the galvanic corrosion monitoring method that nondestructive measurement is carried out in the corrosion of reinforcing bar in the concrete.
Not only simple, economical in the electrochemical method, easily row but also study and use the earliest, be the reinforcing bar half-cell prtential the most widely.It is used with explanation and has a detailed description in ASTM C876-91 " the primary element electric potential method of reinforcing bar in the concrete ".But the half-cell prtential method can only be judged the etch state of reinforcing bar, and can not obtain the corrosion speed of reinforcing bar.
In order to obtain the corrosion speed of reinforcing bar, Dawson etc. have proposed the corrosion behavior of reinforcing bar in the electrochemical impedance spectral method measurement concrete.Generally speaking, the needed time of electrochemical impedance spectrometry is longer, and for the ease of implementing in-site measurement, people have also been developed the electrochemical impedance measuring technique of two frequency methods again.Adoptable instrument is complicated and expensive, is not easy to implement the steel reinforced concrete erosion monitoring at large tracts of land, scene.
Chinese patent CN 1471623A discloses a kind of embeddable corrosion monitoring device that steel reinforced structures is used that is used to implement, and its feature has comprised the polarization resistance that adopts linear polarization method measurement reinforcing bar.If measure corrosion of metal speed in this way, still need to estimate corrosion reaction Stern coefficient B, try to achieve corrosion electric current density Icorr according to formula Icorr=B/Rp then.But with regard to the B value, it is very big that reinforcing bar is under the different etch states its numerical value change, and in general, usually there is very big error in the corrosion electric current density of trying to achieve so.And the influence of concrete medium ohmmic drop can not be effectively eliminated in the corrosion measurement when concrete resistivity is higher of this technology.
Goal of the invention:
The purpose of this utility model is to overcome the shortcoming that exists in the prior art, provide a kind of and can monitor the multiple spot data simultaneously, measure data Concrete Steel Reinforcement Corrode Monitoring Device efficiently, adopt the charge pulse polarization method to measure the corrosion parameter of reinforcing bar in the concrete, the corrosion of monitoring reinforcing bar by the variation of these parameters of periodic monitoring changes, the reinforcement corrosion measurement method of parameters is the measuring method of outage, overcome the shortcoming that linear polarization measurement technique is influenced by the corrosive medium high resistivity easily, and can effectively eliminate the influence of diffusion process corrosion measurement.
In order to realize the foregoing invention purpose, the utility model complete machine comprises charge pulse polarization module, monitoring probe, sensor, modulator-demodular unit, corrosion monitoring software, GSM communication module, CPU control module and power module; Host computer comprises corrosion monitoring software; Power module, charge pulse polarization module, CPU control module constitute slave computer.Monitoring probe is connected with the electrolytic cell cable socket of slave computer through lead with sensor, and the data output end of slave computer connects data communication port, and data communication can be selected wire communication or wireless communication mode; The wire communication pattern adopts RS232/RS485, and slave computer links to each other with the RS-232 serial line interface of PC through RS-485 interface, data bus, RS-485/RS232 translation interface; Wireless communication mode adopts GSM to move public network, and slave computer carries out data communication through data communication port through the modulator-demodular unit of GSM communication module and host computer, finally transmits data to host computer.Wherein said monitoring probe and sensor and slave computer are a group or more, desirable 15 groups at most.
Monitoring probe is connected with the probe socket of slave computer through lead with sensor.Probe socket is received the electrolytic cell socket of charge polarization module again through connecting wire.The amplifier A of charge pulse polarization module testing circuit
1And A
2Output terminal connect standard capacitor C respectively
1~C
4Two ends, K switch
1~K
4When conducting, capacitor C
1~C
4Charging; Capacitor C during disconnection
1~C
4Discharge to electrolytic cell.The RE end of electrolytic cell socket connects operational amplifier A
3Positive input terminal, amplifier A
3Output terminal and amplifier A
4Reverse input end links to each other, amplifier A
4Output terminal is through resistor R
13With amplifier A
6Negative input end connect.Amplifier A
6Output terminal through K switch
6Be connected to the simulating signal accessory power outlet.Three pins of simulating signal accessory power outlet are by the signal input port of lead connection CPU control module, and finally the 12bit A/D converter by CPU control module inside becomes digital signal with analog signal conversion, outputs to host computer.
The CPU control module of the on-the-spot corrosion monitor slave computer that the utility model relates to comprises main control unit, program storage, data-carrier store, serial ports change-over circuit, data communication port, signals collecting port, switching value I/O (I/O) port, mould/number conversion, D/A switch, parallel port expansion, calendar clock, E
2PROM, watchdog circuit constitute, and wherein main control unit is a low-voltage single-chip microcomputer, sheet include 8k bytes can be erasable repeatedly read-only program memory and the Random Access Data storer of 256bytes, compatibility standard MCS-51 order set.Watchdog circuit is to be absorbed in endless loop in order to prevent to be interfered in the Single Chip Microcomputer (SCM) program implementation.Adopt calendar clock chip to realize the function of timing acquiring data.Adopt EEPROM in order to store some important data, and when outage obliterated data not.
The charge pulse polarization module of slave computer comprises: electrolytic cell socket, simulating signal accessory power outlet, D/A input port, polarizing voltage amplifying circuit, charge storage circuit, corrosion potential sampling hold circuit, signal conditioning circuit.The principle of work of charge pulse polarization module is: adopt capacitor C
1~C
4Be the standard capacitance of storing electric charge, before charge pulse polarization beginning, pass through K
1~K
4Control come all to charge to each standard capacitance.The size of polarizing voltage and the selection of standard capacitance are divided into manually and automatic two kinds of patterns.Manual mode is imported by host computer.The quantity that host computer stores on the adjustment criteria electric capacity electric charge by the polarizing voltage size of control D/A input port, promptly what of polarization charge host computer control.Automatic mode is tried to survey by monitoring of software control charge pulse polarization module one by one, analytical calculation is carried out in what, the variation of potential decay curve end to maximum overpotential, valid data, decides test parameters such as best polarization charge and sampling time interval.On the charge pulse polarization module four standard capacitances of storing electric charge are arranged, its nominal value differs ten times successively, forms four kinds of charge polarization scopes from low to high.In the moment standard capacitance outage of measuring beginning and to the electrolytic cell discharge, promptly with the charge polarization monitoring probe of the dose known amounts of storing, and then the CPU control module writes down its polarized potential over time.
In the circuit design of the present utility model, the polarizing voltage amplifying circuit utilizes amplifier A
1And A
2Improve the instantaneous voltage of polarization charging, shorten the transfer time of polarization charge in the charging process, reduce the influence of solution ohmmic drop.The corrosion potential sampling hold circuit is selected the amplifier of high input impedance and low imbalance bias current and the standard capacitance C of low leakage electrode stream for use
5, relay K
5After the disconnection, can keep the variation<0.3mV/100sec of its output voltage.Utilize the corrosion potential sampling hold circuit, can realize corrosion potential easily, avoid utilizing the D/A compensation to remove digital circuit that corrosion potential brings and the interference problem between the mimic channel, can simplify the design of test circuit greatly from motion tracking and elimination.
Corrosion monitor panel of the present utility model comprises: probe socket, AC/DC selector switch, reset button, serial line interface, protective tube are installed port, supply socket.Wherein the AC/DC selector switch is controlled the power supply mode of monitoring device, alternating current adopts civil power, direct current is provided by the 6V accumulator, the both positive and negative polarity of accumulator is the input end of joining power module respectively, by power module DC voltage is increased to 18V, export the D/A input port of charge pulse polarization module then to.Probe socket connects monitoring probe and sensor, and monitoring probe connects research electrode WE, contrast electrode RE and the auxiliary electrode CE of electrolytic cell socket respectively by triple cable; Sensor comprises pH electrode, chlorion sensor.Under any circumstance need interrupt test or interrupt run or appearance unusual, all can be by restarting after the reset button.
On-the-spot corrosion monitoring hardware cell comprises monitoring probe, sensor, monitoring device slave computer and the GSM communication module that is embedded in the concrete.The measuring process of corrosion monitor comprises polarization and polarization process not.Polarization process is to adopt the charge pulse polarization method, regulates and controls successively each monitoring probe by main control unit and measure also image data.Cpu chip has been born all the essential calculating of charge pulse polarization measurement, calculates corrosion rate, Tafel slope and polarization resistance R by the embedded software in the program storage
pWith interface capacitance C
dPolarization process mainly is not to measure chloride ion content in open circuit potential, concrete pH value and the concrete of reinforcing bar.Open circuit potential obtains by the potential difference (PD) between research electrode and the contrast electrode; The chlorion sensor comprises that one is connected to Ag/AgCl electrode and MnO
2The operational amplifier of electrode.
The data of measuring can be stored in data-carrier store, or by the serial ports change-over circuit, directly send host computer to through the GSM communication module.
The long-range wireless network communication of the host computer in on-the-spot corrosion monitor slave computer and the pulpit is by the transmission of GSM communication module.Host computer is controlled the slave computer of monitoring device by the following biography of modulator-demodular unit realization test parameter.
Metal erosion monitoring method provided by the utility model is that outage is measured, and it has overcome the shortcoming that linear polarization measurement technique is influenced by the concrete high resistivity easily, and can effectively eliminate the influence of diffusion process to corrosion measurement.The present invention is simple to operate, and remote monitoring function can be gathered the multiple spot data automatically, has reduced Monitoring Data collection personnel's labour intensity, increases work efficiency greatly.Simultaneously, in light weight, advantages such as volume is little, power saving that the present invention has can adopt multiple power supply mode, and the adaptability that install and use at the scene is good.The present invention can be applied to the important or great reinforced concrete constructional works in field such as bridge spanning the sea, harbor work's harbour, skyscraper, dam, flood-relief channel, high tower.In addition, also can be widely used in corrosion of metal monitoring in the fields such as oil, chemical industry, soil.
Description of drawings:
The theory diagram that Fig. 1 forms for the utility model complete machine.
Fig. 2 is a charge pulse polarization module testing circuit theory synoptic diagram of the present utility model.
Fig. 3 is a CPU control module structured flowchart of the present utility model.
Fig. 4 is the panel construction synoptic diagram of the utility model device.
Embodiment:
During enforcement of the present utility model, its complete machine structure comprises charge pulse polarization module 1, corrosion monitor 2, monitoring probe 3, sensor 4, modulator-demodular unit 5, host computer 6, corrosion monitoring software 7, GSM communication module 8, CPU control module 9, power module 10, slave computer 11, electrolytic cell socket 12, simulating signal accessory power outlet 13, D/A input port 14, polarizing voltage amplifying circuit 15, charge storage circuit 16, corrosion potential sampling hold circuit 17, signal conditioning circuit 18, main control unit 19, program storage 20, data-carrier store 21, serial ports change-over circuit 22, data communication port 23, signals collecting port 24, switching value I/O (I/O) port 25, mould/number conversion 26, D/A switch 27, parallel port expansion 28, calendar clock 29, E
2PROM30, watchdog circuit 31, CPU control module 32, probe socket 33, AC/DC selector switch 34, reset button 35, serial line interface 36, protective tube are installed port 37, supply socket 38 and corrosion monitor panel 39.
The corrosion monitor 2 that the utility model relates to is made up of monitoring probe 3, sensor 4, the modulator-demodular unit 5 at slave computer 11, host computer 6, corrosion monitoring software 7 and GSM communication module 8 and the scene of being installed in.Wherein slave computer 11 comprises CPU control module 9, charge pulse polarization module 1, power module 10.Monitoring probe 3 is connected with the electrolytic cell cable socket of slave computer 11 through lead with sensor 4.The data output end of slave computer 11 connects data communication port, and data communication is selected wireless communication mode.
Charge pulse polarization module 1 of the present utility model comprises: electrolytic cell socket 12, simulating signal accessory power outlet 13, D/A input port 14, polarizing voltage amplifying circuit 15, charge storage circuit 16, corrosion potential sampling hold circuit 17, signal conditioning circuit 18.What of polarization charge host computer 6 control, adopt automatic mode to try one by one to survey by monitoring of software control charge pulse polarization module 1, analytical calculation is carried out in what, the variation of potential decay curve end to maximum overpotential, valid data, decides test parameters such as best polarization charge and sampling time interval.In the moment standard capacitance outage of measuring beginning and to the electrolytic cell discharge, promptly with the charge polarization monitoring probe 3 of the dose known amounts of storing, and then CPU control module 9 its polarized potentials of record over time.
CPU control module 32 of the present utility model comprises main control unit 19, program storage 20, data-carrier store 21, serial ports change-over circuit 22, data communication port 23, signals collecting port 24, switching value I/O (I/O) port 25, mould/number conversion 26, D/A switch 27, parallel port expansion 28, calendar clock 29, E
2PROM 30, watchdog circuit 31 constitute.Wherein the function of each several part is as follows:
Main control unit 19 is low-voltage AT89C52 single-chip microcomputers, sheet include 8k bytes can be erasable repeatedly read-only program memory and the Random Access Data storer (RAM) of 256bytes, compatibility standard MCS-51 order set.The mode that CPU I/O mouth distributes is: P0 is data/address multiplex bus; P2 is an address bus; P1.0 is a feeding-dog signal; P1.1 is the control of dislodging machine; P1.2 is 8880 sequential control ends; P1.6 and P1.7 are I
2C control; INT0 is an A/D EOC signal; INT1 is a clock interrupt signal.Because CPU I/O mouth is limited, native system utilizes parallel port expansion PCF8574 expansion I/O mouth, the actuating of relay of control collection plate.
Watchdog circuit 31 is to be absorbed in endless loop in order to prevent to be interfered in the Single Chip Microcomputer (SCM) program implementation.Utilize watchdog circuit MAX1232 to realize monitoring.After the system software collapse, MAX1232 just produces a high impulse that resets at the RST pin, thereby system software is recovered.
Calendar clock chip 29 adopts PCF8563 to come the sophisticated systems function, the date and time function of providing convenience not only for the user, and can realize the function of timing acquiring data.
Adopt EEPROM 30 in order to store some important data, and when outage obliterated data not.24 serial serial EEPROMs have adopted and have met I
2The PCF8574 chip of C bus protocol, it is few to take I/O mouth line, and volume is little, and capacity is big, and operating voltage range is wide.
Chip PCF8574 are adopted in I/O and interruption expansion 28, and it is a cmos circuit, by two bidirectional bus (I
2C) can make most of MCU realize the expansion of remote I/O mouth.This device comprises 8 accurate bidirectional interfaces and an I
2The C bus interface.The PCF8574 current drain is very low, and output latch has high current drive capability, can directly drive relay.
D/A switch 27 adopts 12bit DAC7512.And signal becomes digital quantity to send into single-chip microcomputer by mould/number conversion 26 by the AD574 sample conversion by amplifying with the conditioning back, is handled by single-chip microcomputer.
Corrosion monitor panel 39 of the present utility model comprises: probe socket 33, AC/DC selector switch 34, reset button 35, serial line interface 36, protective tube are installed port 37, supply socket 38.Power supply mode by AC/DC selector switch 34 control monitoring devices adopts civil power.Probe socket 33 connects monitoring probe and sensor, and monitoring probe 3 connects research electrode WE, contrast electrode RE and the auxiliary electrode CE of electrolytic cell socket 12 respectively by triple cable; Sensor 4 adopts an Ag/AgCl electrode and MnO
2The electrode contrast electrode forms battery.
The data of measuring directly send host computer 6 by serial ports change-over circuit 22 to through GSM/TC35T communication module 8.
Whole measuring process can be divided into three steps, i.e. parameter setting, sampling and data processing.The parameter setting comprises probe SA, electrode area AR, polarization mode, measurement at interval.The optional value of SA is 00,01 ..., 14,15; The unit of AR is cm
2Polarization mode is negative electrodeization or anodization; Measure optional time interbody spacer unit at interval and be minute, hour and day.After the parameter setting is finished, host computer passes to slave computer with the parameter setting, and device begins to measure the open circuit potential of concrete reinforcement, after open circuit potential tends towards stability, promptly begin tested systems is carried out the charge pulse polarization by the enter key instrument, the electrode potential of record research simultaneously over time.After sampling process finished, slave computer 11 carried out data communication through data communication port through the modulator-demodular unit 5 of GSM/TC35T communication module 8 and host computer 7, and data transmission is arrived host computer 7.If plan to adopt complicated equivalent-circuit model deal with data, then upload overpotential-time raw data by telecommunication control slave computer 11, the data fitting function by corrosion monitoring software 7 in the host computer 6 carries out curve fitting.After The Fitting Calculation finished, the various electrochemical parameters that obtain were presented on host computer 6 displays.
According to the above-mentioned setting of the utility model device, the analog equivalent circuit to be measured, its polarization overpotential die-away curve and matched curve thereof show the design that meets invention.The data and the theoretical fitting curve of test have extraordinary consistance.Except " zero " sampled point, solution resistance does not exert an influence to polarization amplitude, overpotential die-away curve and fitting result.Therefore, the present invention can eliminate the influence of solution resistance between research electrode and the contrast electrode.For analog equivalent circuit wherein, the nominal value of resistance is respectively 670 Ω, 2000 Ω and 4630 Ω, the nominal value of electric capacity is respectively 100 μ F, 47 μ F and 4.7 μ F, actual value and the nominal value of considering general capacitor have certain error, we adopt electrochemical impedance spectroscopy (EIS) method that mimic channel is proofreaied and correct, by the result contrast of charge pulse polarization with EIS, the difference of resistance, capacity measurement shows that this measurement mechanism has good measuring accuracy and reliability in 5% between the two.
The utility model is monitored the actual corrosion system of reinforced concrete.The monitoring place is the suspension rod steel wire that 5-linked is striden the crossbeam position of steel pipe concrete half-through ribbed arch bridge, 324 meters of bridge total lengths, and the arch axis line is a second-degree parabola, its main arch structure is made up of arch rib, horizontal connection structure, suspension rod.Each suspension rod is 84 φ, 5 high-strength zinc-coated wires, and what employing was fixed in the lower end is the form of bulb-end anchorage.The device that employing the present invention relates to is monitored the corrosion of crossbeam position suspension rod steel wire, assesses the corrosion inhibition of reinforcing bar corrosion inhibitor to steel wire simultaneously.The result of field monitoring shows: corrosion inhibitor has the obvious suppression effect to the corrosion of steel wire; The regular interpolation of corrosion inhibitor can strengthen corrosion inhibition.The corrosion mitigating effect of corrosion inhibitor increases the weight of and reduces with the original etch state of steel wire.