CN108332891B - Reinforced concrete rust testing mold and rust process stress monitoring method - Google Patents
Reinforced concrete rust testing mold and rust process stress monitoring method Download PDFInfo
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- 238000012360 testing method Methods 0.000 title claims abstract description 126
- 239000011150 reinforced concrete Substances 0.000 title claims abstract description 121
- 238000000034 method Methods 0.000 title claims abstract description 76
- 238000012544 monitoring process Methods 0.000 title claims abstract description 47
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 title claims abstract description 34
- 239000004567 concrete Substances 0.000 claims abstract description 19
- 238000012545 processing Methods 0.000 claims abstract description 7
- 229910000831 Steel Inorganic materials 0.000 claims description 98
- 239000010959 steel Substances 0.000 claims description 98
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 claims description 46
- 230000007797 corrosion Effects 0.000 claims description 27
- 238000005260 corrosion Methods 0.000 claims description 27
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 12
- 238000005520 cutting process Methods 0.000 claims description 8
- 238000005259 measurement Methods 0.000 claims description 8
- 238000005498 polishing Methods 0.000 claims description 8
- 238000006073 displacement reaction Methods 0.000 claims description 7
- 238000007789 sealing Methods 0.000 claims description 7
- 239000004593 Epoxy Substances 0.000 claims description 6
- 230000003068 static effect Effects 0.000 claims description 5
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 3
- 239000002253 acid Substances 0.000 claims description 3
- 238000004364 calculation method Methods 0.000 claims description 3
- 239000011248 coating agent Substances 0.000 claims description 3
- 238000000576 coating method Methods 0.000 claims description 3
- 238000005286 illumination Methods 0.000 claims description 3
- 238000000465 moulding Methods 0.000 claims description 3
- 238000005554 pickling Methods 0.000 claims description 3
- 230000002787 reinforcement Effects 0.000 claims description 3
- 238000005476 soldering Methods 0.000 claims description 3
- 238000012423 maintenance Methods 0.000 claims description 2
- 230000001502 supplementing effect Effects 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 2
- 229910001294 Reinforcing steel Inorganic materials 0.000 claims 16
- 238000005406 washing Methods 0.000 claims 1
- 238000004519 manufacturing process Methods 0.000 abstract description 6
- 238000002955 isolation Methods 0.000 abstract description 4
- 238000011156 evaluation Methods 0.000 abstract description 3
- 238000002360 preparation method Methods 0.000 abstract description 2
- 238000006243 chemical reaction Methods 0.000 abstract 1
- 238000001514 detection method Methods 0.000 description 9
- 238000010586 diagram Methods 0.000 description 6
- 229910001220 stainless steel Inorganic materials 0.000 description 5
- 239000010935 stainless steel Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 3
- 238000005336 cracking Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000000691 measurement method Methods 0.000 description 3
- 230000003014 reinforcing effect Effects 0.000 description 3
- 238000009826 distribution Methods 0.000 description 2
- WABPQHHGFIMREM-OIOBTWANSA-N lead-204 Chemical compound [204Pb] WABPQHHGFIMREM-OIOBTWANSA-N 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 239000003973 paint Substances 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000009659 non-destructive testing Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
- G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
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Abstract
The invention provides a reinforced concrete rust testing die and a rust process stress monitoring method, comprising the following steps: firstly, manufacturing an experimental test mould, wherein the experimental test mould is mainly a concrete test piece with a reinforced bar, a miniature strain gauge with a wire is arranged in the reinforced bar, then a CCD camera and a strain acquisition instrument are communicated to monitor the outside and the inside of the reinforced concrete test piece respectively, and then the strain value of the reinforced concrete test piece is obtained through the processing and conversion of a digital image correlation system; the monitoring method has the advantages of low requirements on measuring environment and vibration isolation, strong controllability, short single test period, easy processing and manufacturing of the reinforced concrete test piece, small occupied space, low cost and simple preparation, can carry out full-field real-time monitoring on rust in the whole life cycle of the reinforced concrete test piece structure, and can obtain an integral macroscopic model; the invention can be carried out in a laboratory, can also be combined with engineering practice to carry out real-time monitoring, and provides a new measuring method for structural safety evaluation.
Description
Technical Field
The invention belongs to the technical field of monitoring of a corrosion process of reinforced concrete, relates to a monitoring method, and in particular relates to a reinforced concrete corrosion test die and a corrosion process stress monitoring method.
Background
At present, the nondestructive testing method used in the reinforced concrete corrosion process comprises the following steps: manual observation method, ultrasonic detection method, radar detection method, acoustic Emission (AE) detection method, infrared thermal image detection and optical measurement method, etc., specifically as follows:
the manual observation method is to draw a visual observation result into a sketch, and measure the crack width by using a crack graduated scale, a magnifying glass and the like, which requires a great deal of manpower and time and has low precision;
the ultrasonic detection method reflects the compressive strength of the concrete by utilizing the correlation between the ultrasonic propagation speed and rebound value and the compressive strength of the concrete, and can calculate the crack depth and determine the position of an internal crack by utilizing the time (acoustic time) of the ultrasonic propagation in the concrete, the change of the amplitude value and the frequency value;
the radar detection method is to use an antenna to emit high-frequency electromagnetic waves, and to infer the internal structure of a medium according to the analysis of the phase, amplitude and waveform information of the received waves by utilizing the principle that the propagation path, electromagnetic field distribution and waveform of the electromagnetic waves change along with the electrical property and geometric shape of the propagation medium;
the Acoustic Emission (AE) method is to collect acoustic emission signals generated in the deformation or cracking process of materials by a special detection instrument, and then to obtain parameters representing defect characteristics through computer processing, so as to analyze and judge the size, position, state and development trend of the damage of the materials, and detect the position, size, expansion condition, type and depth of cracks;
the infrared thermal image detection refers to a detection technology for visually displaying discontinuous defects of materials, structures and joints by using an infrared thermal imager to detect infrared energy radiated by an object and forming a thermal image according to temperature field distribution on the surface of the object.
Although the prior method can acquire the information of the cracks of the reinforced concrete structure, a large amount of manpower and material resources are required, the method is limited to the external factors such as the position of the terrain, the micro cracks generated by fire and burst are more difficult to capture, in addition, the method of micro or macro fracture mechanics is utilized to carry out mechanical analysis and safety assessment on the damaged concrete structure, accurate description on crack information of the concrete structure at various stages is required, and then a mechanical analysis model is established, however, the traditional crack acquisition workload is large, and the acquired information is rough.
Accordingly, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art.
Disclosure of Invention
The invention aims to overcome the defects of the prior art on the method for monitoring the stress change in the reinforced concrete corrosion process, and provides a reinforced concrete corrosion test die and a corrosion process stress monitoring method. The invention utilizes the principle of combining the digital image correlation technique and the resistance strain gauge measurement, the optical measurement and the digital image processing method of the digital image correlation technique carry out high-precision measurement on engineering mechanics (such as displacement, deformation, stress, strain, speed and the like), the resistance strain gauge measurement method has high precision and stable measurement result, the advantages of the two measurement methods are combined to carry out long-term observation, non-contact and global measurement on a reinforced concrete test piece, and the monitoring method has low requirements on measuring environment and vibration isolation, has strong universality, and can efficiently, conveniently, quickly and globally monitor the stress change of the reinforced concrete test piece in the rust process.
In order to achieve the above object, the present invention provides the following technical solutions:
a test mold for reinforced concrete rust, the test mold comprising:
the die groove is cuboid, and a cavity is formed in the upper opening and the inside of the die groove;
the baffle plate is arranged in the cavity of the die groove and comprises a first baffle plate and a second baffle plate; the first baffle is fixedly arranged at one end of the mold groove, the second baffle is fixedly arranged at the other end of the mold groove, a space is reserved between the first baffle and the inner side wall at one end of the mold groove, and the second baffle is tightly attached to the inner side wall at the other end of the mold groove;
the steel bar test piece is positioned in the cavity of the die groove, one end part of the steel bar test piece passes through the first baffle plate, the other end part of the steel bar test piece passes through the second baffle plate, and the first baffle plate and the second baffle plate play a role in auxiliary reinforcement molding; the steel bar test piece is a test piece formed by adhering and combining a part of each of two different steel bars, a plurality of miniature strain gages with wires are adhered to the inside of the steel bar test piece, the wires are led out from one end part of the steel bar test piece to the outside, and the other end part of the steel bar test piece is sealed;
and concrete is poured into the residual cavity of the whole mold groove and is bonded with the steel bar test piece, so that the steel bar concrete test piece is obtained.
In the testing mold for reinforced concrete corrosion, preferably, the first baffle and the second baffle are vertically and fixedly clamped in the inner cavity of the mold groove, the lower bottom surface of the baffle is in contact with the bottom of the mold groove, and the two side wall surfaces of the baffle are in contact with the two side wall surfaces of the mold groove.
In the test mold for reinforced concrete corrosion as described above, preferably, the structure of the reinforced concrete test piece is specifically: cutting two steel bars longitudinally, and then re-adhering a part of the cut steel bars together to form a steel bar test piece; grooves are dug in the middle of two parts of each cut steel bar, a plurality of miniature strain gauges with leads are stuck in the grooves, and the leads are led out from one end of the steel bar to the outside.
In the test mold for reinforced concrete rust as described above, preferably, the reinforcing bar test piece is composed of a cut-out screw-thread reinforcing bar and a common reinforcing bar; preferably, the specification of the deformed bar and the common bar is phi 20mm.
In the test mold for reinforced concrete rust as described above, preferably, the reinforced concrete test piece has dimensions of 100mm×100mm×250mm; preferably, the groove is a semicircular groove; still preferably, the semi-circular recess has a diameter of 15mm.
In the reinforced concrete rust testing mold, preferably, a plurality of micro strain gauges are uniformly distributed along the length direction of the groove at intervals of 62.5 mm; preferably, the number of micro-strain gages is four.
A reinforced concrete rust process full field stress field monitoring method using the reinforced concrete rust test die of any one of the above, the reinforced concrete rust process full field stress field monitoring method comprising the steps of:
step one, preparing a steel bar test piece: respectively taking one of the thread steel bar and the common steel bar, derusting and polishing the thread steel bar and the common steel bar, cutting the thread steel bar and the common steel bar along the longitudinal direction of the thread steel bar and the common steel bar from the middle, respectively digging a groove in the middle of the two cut steel bars, pasting a plurality of miniature strain gages with wires in the grooves at the upper and lower half pairs of corresponding positions, bundling the two cut thread steel bars and the common steel bar into a steel bar test piece, leading the wires out from one end part of the steel bar test piece, sealing the other end part of the steel bar test piece by epoxy, and sealing joints between the two cut steel bars of the steel bar test piece by epoxy;
preparing a reinforced concrete test piece: placing the reinforced concrete test piece prepared in the step one in a mold groove, enabling two ends of the reinforced concrete test piece to respectively penetrate through the first baffle plate and the second baffle plate, and then pouring concrete into a test mold to obtain a reinforced concrete test piece for later use;
step three, treating the reinforced concrete test piece: performing standard maintenance on the reinforced concrete test piece prepared in the second step, and demolding; cutting off the exposed end of the steel bar at the other end part of the reinforced concrete test piece, which is not led out of the lead, polishing and flattening the surface of the reinforced concrete test piece until the surface is smooth, and finally manually coating black-white alternate speckles on the surface of the reinforced concrete test piece for later use;
step four, monitoring the full-field stress field monitoring of the reinforced concrete corrosion process:
connecting the lead led out from the reinforced concrete test piece prepared in the step three with a strain acquisition instrument for acquiring the numerical value of the miniature strain gauge;
and acquiring images of the front surface and the upper surface of the reinforced concrete test piece in real time by adopting a CCD camera outside the reinforced concrete test piece until the reinforced concrete test piece is completely cracked, and stopping acquiring when rust products overflow from the front surface.
In the method for monitoring the full-field stress field in the reinforced concrete corrosion process, preferably, in the first step, pickling is performed before rust removal and polishing of the deformed bar and the common bar; preferably, the acid solution used for pickling is hydrochloric acid solution; still preferably, the hydrochloric acid in the hydrochloric acid solution is: the proportion of water is (8-13): 100.
in the method for monitoring the full-field stress field in the reinforced concrete corrosion process, preferably, in the fourth step, the strain collecting instrument is a DH3815N static strain collecting instrument; preferably, in the third step, the standard curing period is 28d.
In the method for monitoring the full-field stress field of the reinforced concrete corrosion process, preferably, in the first step, the wire is electrically connected with the filament on the micro-strain gauge by using soldering tin so as to ensure a good passage between the wire and the micro-strain gauge.
Compared with the closest prior art, the technical scheme provided by the invention has the following excellent effects:
the test and test die is convenient to set up, has low requirements on measuring environment and vibration isolation, has strong controllability, short single test period, easy processing and manufacturing of the reinforced concrete test piece, small occupied space and low cost, is simple to prepare, can carry out full-field real-time monitoring on rust in the whole life cycle of the reinforced concrete test piece structure, and can obtain an integral macroscopic model; the invention can be carried out in a laboratory, can also be combined with engineering practice to carry out real-time monitoring, and provides a new measuring method for structural safety evaluation.
Drawings
Fig. 1 is a schematic structural diagram of a test piece mold for reinforced concrete rust in an embodiment of the present invention;
FIG. 2 is a schematic view of the installation of the micro-strain gauge of FIG. 1;
FIG. 3 is a front partial view of a cured test piece with speckles according to an embodiment of the present invention;
FIG. 4 is a top partial view of a test piece that has been subject to the speckle of the guard bands in an embodiment of the invention;
FIG. 5 is a schematic diagram of a digital image correlation system according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of an image processing system according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of a digital image correlation system in accordance with an embodiment of the present invention;
FIG. 8 is a schematic view of the acquisition of strain gauges inside a reinforced concrete test piece in an embodiment of the invention;
fig. 9 is a schematic diagram of a full-field stress monitoring system for reinforced concrete test pieces in an embodiment of the invention.
In the figure: 1. a mold groove; 2. a steel bar test piece; 101. a second baffle; 102. a first baffle; 201. cut steel bar; 202. a groove; 203. a micro strain gauge; 204. and (5) conducting wires.
Detailed Description
The following description of the technical solutions in the embodiments of the present invention will be clear and complete, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which are derived by a person skilled in the art based on the embodiments of the invention, fall within the scope of protection of the invention.
The invention will be described in detail below with reference to the drawings in connection with embodiments. It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.
In the description of the present invention, the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is merely for convenience of description of the present invention and does not require that the present invention must be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. The terms "coupled" and "connected" as used herein are to be construed broadly and may be, for example, fixedly coupled or detachably coupled; either directly or indirectly through intermediate components, the specific meaning of the terms being understood by those of ordinary skill in the art as the case may be.
Example 1
As shown in fig. 1 to 7, the present invention provides a reinforced concrete rust testing mold and a rust process stress monitoring method, the testing mold comprises:
the mold groove 1 is a cuboid, and a cavity is formed in the upper opening of the mold groove 1;
a baffle plate which is arranged in the cavity of the mould groove 1 and comprises a first baffle plate 102 and a second baffle plate 101; the first baffle plate 102 is fixedly arranged at one end of the die groove 1, the second baffle plate 101 is fixedly arranged at the other end of the die groove 1, a space is reserved between the first baffle plate 102 and the inner side wall at one end of the die groove 1, and the second baffle plate 101 is tightly attached to the inner side wall at the other end of the die groove 1;
the steel bar test piece 2 is positioned in the cavity of the die groove 1, one end part of the steel bar test piece 2 passes through the first baffle plate 102, the other end part of the steel bar test piece 2 passes through the second baffle plate 101, and the first baffle plate 102 and the second baffle plate 101 play a role in auxiliary reinforcement molding; the steel bar test piece 2 is a test piece formed by adhering and combining a part of each of two different steel bars, a plurality of micro strain gauges 203 with wires 204 are adhered inside the steel bar test piece 2, the wires 204 are led out from one end of the steel bar test piece 2 to the outside, and the other end of the steel bar test piece 2 is sealed;
and concrete is poured into the residual cavity of the whole mold groove 1 and is adhered with the reinforced concrete test piece 2, so that the reinforced concrete test piece with the dimensions of 100mm multiplied by 250mm is obtained.
The first baffle plate 102 and the second baffle plate 101 are vertically and fixedly clamped in the inner cavity of the die groove 1, the lower bottom surface of the baffle plate is in contact with the bottom of the die groove 1, and the two side wall surfaces of the baffle plate are in contact with the two side wall surfaces of the die groove 1.
The structure of the steel bar test piece 2 is specifically as follows: the two steel bars are respectively a threaded steel bar and a common steel bar with the specification of phi 20mm, the two steel bars are longitudinally cut, and then a part of the cut steel bars are respectively taken and are bonded together again to form a steel bar test piece 2;
semicircular grooves 202 with the diameter of 15mm are dug in the middle of two parts of each cut steel bar 201, four micro strain gauges 203 with wires 204 are stuck in the grooves 202, the micro strain gauges 203 are uniformly distributed at intervals of 62.5mm along the length direction of the grooves 202, the wires 204 are led out from one end part of each steel bar to the outside, and the diameter of the grooves 202 is set to be 15mm mainly for facilitating sticking of the micro strain gauges 203;
the method for monitoring the full-field stress field in the reinforced concrete corrosion process comprises the following steps:
step one, preparing a steel bar test piece 2: considering the different influences of different types of steel bars on corrosion of a test piece, respectively taking one of the deformed bar and the common steel bar, and firstly utilizing the proportion (8-13): 100, then rust removing and polishing are carried out on the threaded steel bars and the common steel bars, a groove 202 is respectively dug in the middle of the threaded steel bars and the common steel bars in the longitudinal direction of the threaded steel bars and the common steel bars, a plurality of micro strain gauges 203 with wires 204 are stuck in the grooves 202 at the corresponding positions of the upper half and the lower half, wherein the wires 204 are electrically connected with filaments on the micro strain gauges 203 by soldering tin so as to ensure a good passage between the wires 204 and the micro strain gauges 203, the two cut threaded steel bars and the common steel bars are bundled into a steel bar test piece 2, the wires 204 are led out from one end part of the steel bar test piece 2 to the outside, the other end part of the steel bar test piece 2 is subjected to epoxy sealing treatment, and the joint between the two cut steel bars 201 of the steel bar test piece 2 is subjected to epoxy sealing treatment for standby;
preparing a reinforced concrete test piece: placing the reinforced concrete test piece 2 prepared in the first step in a mold groove 1, enabling two ends of the reinforced concrete test piece to respectively pass through a first baffle plate 102 and a second baffle plate 101, and pouring concrete into a test mold to obtain a reinforced concrete test piece for later use;
step three, treating the reinforced concrete test piece: performing 28d standard curing on the reinforced concrete test piece prepared in the second step, demolding, and setting the curing period to be 28d according to the standard that the curing time is not less than 28d and the curing time is required to be timely cured after concrete pouring;
cutting off the exposed end of the steel bar at the other end part of the reinforced concrete test piece, which is not led out of the lead 204, polishing and leveling the surface of the reinforced concrete test piece until the surface is smooth, and finally manually coating black-white alternate speckles on the surface of the reinforced concrete test piece for standby, wherein the speckles mainly are used for guaranteeing the uniqueness of the pixel points of the acquisition surface, and the concrete practice is that the surface of the test piece is sprayed with matte paint manually by hand;
and step four, monitoring the full-field stress field monitoring of the reinforced concrete corrosion process by adopting a static strain collector with the model of DH 3815N:
connecting a lead 204 led out from the reinforced concrete test piece prepared in the third step with a strain acquisition instrument for acquiring the numerical value of the miniature strain gauge 203;
the CCD camera is adopted outside the reinforced concrete test piece to collect images of the front surface and the upper surface of the reinforced concrete test piece in real time until the reinforced concrete test piece is completely cracked, and the collection is stopped when rusted products overflow from the front surface, because once the reinforced concrete test piece is rusted, the cracks of the reinforced concrete test piece are expanded to the surface and finally gradually longitudinally penetrate through the whole test piece, and the rusted objects can overflow from the front surface and the rear surface, so that the overflow condition of the front rusted objects is convenient to observe from the view point of observation.
In this embodiment, as shown in fig. 1-2, in the manufacturing process of a reinforced concrete test piece, firstly taking one common steel bar and each screw steel bar, then cutting the common steel bar and each screw steel bar along a central line, then excavating a groove in the middle of the cut steel bar, then installing a miniature strain gauge with a wire in the groove, bundling the half steel bars together through a wire harness, performing epoxy sealing treatment on the end without the wire and the joint of the two half steel bars, then unwinding the wire harness, placing the reinforced concrete test piece on a first baffle plate and a second baffle plate in a test piece mold, and then pouring concrete to finally obtain the reinforced concrete test piece;
3-4, which are schematic diagrams of speckles formed by manually spraying matt paint, the speckles can ensure uniqueness when pixels are collected on the surface of a reinforced concrete test piece;
as shown in fig. 5, the reinforced concrete test piece is externally provided with an external photometric monitoring system consisting of two white light sources, a CCD camera and a computer, and the specific process is as follows: the two white light sources carry out illumination light supplementing on the reinforced concrete test piece, and then the CCD camera synchronously and periodically collects the change images of the surface of the reinforced concrete test piece;
as shown in fig. 6, the operation of the illumination monitoring system is as follows: and the CCD camera periodically shoots the surface of the reinforced concrete test piece, the acquired photo is transmitted back to the computer, and then image processing software related to MATLAB processes the pixel position displacement change of the photo and converts the pixel position displacement change into a strain value of a related point. )
FIG. 7 shows, specifically illustrates the meaning of the presence of speckle, the speckle is mathematically transformed into a strain value by deformation back and forth, (a) the pre-deformation image represents a pixel point when the object is free from rusting and cracking, and (b) the post-deformation image is the shape of the movement position of the stress of the pixel point after rusting and cracking;
5-7, the method is composed of a DH3815N static strain acquisition instrument, a CCD camera, a light source, a computer, a power supply and a reinforced concrete test piece, wherein the acquired internal strain value of the reinforced concrete is combined with photo-measurement photo data acquired outside the test piece, so that a complete monitoring system is formed.
In the concrete implementation, the brightness and stability of the light source are ensured, the static strain acquisition instrument acquires a group of data every 5min, the CCD camera acquires a group of pictures every 30min until the reinforced concrete test piece is completely cracked, and the acquisition is stopped when rust overflows from the front.
The monitoring method can directly measure the internal strain value of the steel bar, and the picture acquired by the CCD camera is subjected to related calculation through related Matlab software to obtain the strain value, displacement and corresponding pixels of the surface. The values are combined, and the stress condition of the reinforced concrete test piece in the rust process can be obtained through the calculation formula of the rust expansion force of the reinforced concrete test piece provided by the prior literature, so that an integral macroscopic theoretical model is finally formed.
Example 2
As shown in fig. 8 to 9, in this embodiment, in order to accelerate the rust rate of the reinforced concrete test piece, a solution and a stainless steel sheet are disposed in the reinforced concrete test piece by:
firstly, placing a stainless steel sheet capable of conducting electricity in a test piece groove formed in the manufacturing process of a reinforced concrete test piece;
step two, adding a solution capable of accelerating the corrosion rate of the reinforced concrete test piece into the test piece groove above the stainless steel sheet;
and thirdly, switching on a cathode of a power supply on the stainless steel sheet, and switching on an anode of the power supply on the surface of the reinforced concrete test piece, so that a closed loop with an electric acceleration effect is formed.
The added solution accelerates the corrosion rate of the reinforced concrete, in addition, the stainless steel sheet and the reinforced concrete are added with an external power supply to form a closed loop for accelerating the corrosion rate, and the corrosion rate of the reinforced concrete test piece is further accelerated, so that the experimental period of the monitoring method is shortened. Other implementation steps are the same as those of embodiment 1, and will not be repeated here.
Table 1 shows specific values of the strain value, displacement amount and pixel value of the reinforced concrete test piece obtained by the monitoring method.
Table 1 strain, displacement and pixel values obtained by the present monitoring method
In summary, the technical scheme of the invention also has the following beneficial technical effects:
compared with the prior art, the full-field stress field monitoring method for the reinforced concrete corrosion process has the advantages of convenience in setting up the experimental test die, low requirement on measuring environment and vibration isolation, strong controllability, short single test period, easiness in processing and manufacturing test pieces, small occupied space, low cost and simplicity in preparation, and can monitor the whole field of the reinforced concrete corrosion process in the whole life cycle of the reinforced concrete test piece concrete structure in real time, and an integral macroscopic model can be obtained.
The monitoring method not only can be carried out in a laboratory, but also can be combined with engineering practice to carry out real-time monitoring, thereby providing a new measuring method for structural safety evaluation.
The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the particular embodiments disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
Claims (6)
1. A method of monitoring a full field stress field of a reinforced concrete rust process using a test die for reinforced concrete rust, the test die comprising:
the die groove is cuboid, and a cavity is formed in the upper opening and the inside of the die groove;
the baffle plate is arranged in the cavity of the die groove and comprises a first baffle plate and a second baffle plate; the first baffle is fixedly arranged at one end of the mold groove, the second baffle is fixedly arranged at the other end of the mold groove, a space is reserved between the first baffle and the inner side wall at one end of the mold groove, and the second baffle is tightly attached to the inner side wall at the other end of the mold groove;
the first baffle plate and the second baffle plate are vertically and fixedly clamped in the inner cavity of the mold groove, the lower bottom surface of the baffle plate is contacted with the bottom of the mold groove, and the two side wall surfaces of the baffle plate are contacted with the two side wall surfaces of the mold groove;
the steel bar test piece is positioned in the cavity of the die groove, one end part of the steel bar test piece passes through the first baffle plate, the other end part of the steel bar test piece passes through the second baffle plate, and the first baffle plate and the second baffle plate play a role in auxiliary reinforcement molding; the steel bar test piece is a test piece formed by adhering and combining a part of each of two different steel bars, a plurality of miniature strain gages with wires are adhered to the inside of the steel bar test piece, the wires are led out from one end part of the steel bar test piece to the outside, and the other end part of the steel bar test piece is sealed;
the structure of the steel bar test piece is specifically as follows: cutting two steel bars longitudinally, and then re-adhering a part of the cut steel bars together to form a steel bar test piece;
grooves are dug in the middle of two parts of each cut steel bar, a plurality of miniature strain gauges with leads are stuck in the grooves, and the leads are led out from one end part of the steel bar to the outside;
the concrete is poured into the residual cavity of the whole mold groove and is bonded with the steel bar test piece, so that a steel bar concrete test piece is obtained;
the method for monitoring the full-field stress field in the reinforced concrete corrosion process comprises the following steps:
step one, preparing a steel bar test piece: respectively taking one of the thread reinforcing steel bars and the common reinforcing steel bars, derusting and polishing the thread reinforcing steel bars and the common reinforcing steel bars, cutting the thread reinforcing steel bars and the common reinforcing steel bars from the middle in the longitudinal direction of the thread reinforcing steel bars and the common reinforcing steel bars, respectively digging a groove in the middle of the two cut reinforcing steel bars, pasting a plurality of micro strain gauges with wires in the grooves at the upper and lower half pairs of corresponding positions, wherein the number of the micro strain gauges is four, the micro strain gauges are uniformly distributed along the length direction of the groove at intervals of 62.5mm, bundling the two cut thread reinforcing steel bars and the common reinforcing steel bars into a reinforcing steel bar test piece, leading the wires out from one end part of the reinforcing steel bar test piece, sealing the other end part of the reinforcing steel bar test piece by epoxy, and sealing joints between the two cut reinforcing steel bars forming the reinforcing steel bar test piece for standby;
preparing a reinforced concrete test piece: placing the reinforced concrete test piece prepared in the step one in a mold groove, enabling two ends of the reinforced concrete test piece to respectively penetrate through the first baffle plate and the second baffle plate, and then pouring concrete into a test mold to obtain a reinforced concrete test piece for later use;
step three, treating the reinforced concrete test piece: performing standard maintenance on the reinforced concrete test piece prepared in the second step, and demolding;
cutting off the exposed end of the steel bar at the other end part of the reinforced concrete test piece, which is not led out of the lead, polishing and flattening the surface of the reinforced concrete test piece until the surface is smooth, and finally manually coating black-white alternate speckles on the surface of the reinforced concrete test piece for later use;
step four, monitoring the full-field stress field monitoring of the reinforced concrete corrosion process:
connecting the lead led out from the reinforced concrete test piece prepared in the step three with a strain acquisition instrument for acquiring the numerical value of the miniature strain gauge, namely the internal strain value of the reinforced concrete test piece;
the method comprises the steps that a light measurement monitoring system is arranged outside a reinforced concrete test piece, the light measurement monitoring system comprises two white light sources, a CCD (charge coupled device) camera and a computer, the two white light sources are used for carrying out illumination light supplementing on the reinforced concrete test piece, the CCD camera is used for collecting images of the front surface and the upper surface of the reinforced concrete test piece in real time until the reinforced concrete test piece is completely cracked, collection is stopped when rust products overflow from the front surface, the collected images are uploaded to the computer, and strain values, displacement amounts and corresponding pixels on the surface of the reinforced concrete test piece are obtained through processing according to MATLAB related image processing software in the computer;
and (3) obtaining the stress condition of the reinforced concrete test piece in the rust process through a calculation formula of the rust expansion force of the reinforced concrete test piece, and finally forming an integral macroscopic theoretical model.
2. The method for monitoring the full-field stress field of the reinforced concrete corrosion process according to claim 1, wherein the steel bar test piece consists of a cut screw-thread steel bar and a common steel bar;
the specification of the deformed bar and the common bar is phi 20mm.
3. The method for monitoring the full-field stress field of the reinforced concrete corrosion process according to claim 1, wherein the reinforced concrete test piece has the dimensions of 100mm by 250mm;
the grooves are semicircular grooves; the diameter of the semicircular groove is 15mm.
4. The method for monitoring the full-field stress field of the reinforced concrete rust process according to claim 1, wherein in the first step, pickling is carried out before rust removal and polishing of the deformed bar and the common bar;
the acid solution adopted in the acid washing is hydrochloric acid solution;
hydrochloric acid in the hydrochloric acid solution: the proportion of water is (8-13): 100.
5. the method for monitoring the full-field stress field of the reinforced concrete corrosion process according to claim 1, wherein in the fourth step, a DH3815N static strain acquisition instrument is adopted as the strain acquisition instrument; in the third step, the standard curing period is 28d.
6. The method for monitoring the full-field stress field of the rust process of the reinforced concrete according to claim 1, wherein in the first step, the wire is electrically connected with the filament on the micro-strain gauge by using soldering tin so as to ensure a good passage between the wire and the micro-strain gauge.
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| CN108943376B (en) * | 2018-08-24 | 2020-06-09 | 三峡大学 | Method for prefabricating concrete cracks and reinforcing steel bar corrosion defects in complete reinforced concrete foundation structure |
| CN108982348B (en) * | 2018-09-18 | 2022-01-25 | 广东电网有限责任公司 | Underground concrete structure steel corrosion nondestructive diagnosis device |
| CN109557017B (en) * | 2018-11-15 | 2021-04-20 | 北京科技大学 | Corrosion resistance experiment method for steel bar for tropical marine atmospheric environment concrete structure |
| CN109669028B (en) | 2019-03-04 | 2021-06-15 | 青岛理工大学 | Method for measuring cracking and rusty swelling force of concrete caused by reinforcement rusty swelling |
| CN112881404A (en) * | 2021-01-12 | 2021-06-01 | 王玮佳 | Deformed steel bar appearance defect detection device |
| CN114838852B (en) * | 2022-05-10 | 2023-05-30 | 重庆科技学院 | Experimental device and experimental method for determining direction of geological stress field |
| CN114878453B (en) * | 2022-07-11 | 2022-10-18 | 哈尔滨工业大学 | Experimental device and experimental method for regional corrosion in reinforced concrete frame |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6259824A (en) * | 1985-09-11 | 1987-03-16 | Shimizu Constr Co Ltd | Nondestructive stress measuring method for iron reinforcing bar |
| CN201335748Y (en) * | 2008-11-28 | 2009-10-28 | 湖南科技大学 | Detecting system based on concrete box girder bridge web-plate vertical pre-stressed reinforcing steel tensioning force |
| CN204255818U (en) * | 2014-10-15 | 2015-04-08 | 浙江大学 | For the pilot system of the information acquisition of concrete surface Initial Cracking and identification |
| CN106932338A (en) * | 2017-04-11 | 2017-07-07 | 青岛理工大学 | Extravasation electricity accelerates steel bar corrosion test device and building method |
| CN106932441A (en) * | 2017-03-17 | 2017-07-07 | 青岛理工大学 | The corrosion part and test device and method of testing in prefabricated crack |
| CN107843554A (en) * | 2017-12-08 | 2018-03-27 | 信阳师范学院 | A kind of reinforced concrete interface bond stress test device and preparation method |
| CN208076066U (en) * | 2018-04-17 | 2018-11-09 | 青岛理工大学 | A kind of testing mould of Corroded Reinforced Concrete |
-
2018
- 2018-04-17 CN CN201810342631.XA patent/CN108332891B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6259824A (en) * | 1985-09-11 | 1987-03-16 | Shimizu Constr Co Ltd | Nondestructive stress measuring method for iron reinforcing bar |
| CN201335748Y (en) * | 2008-11-28 | 2009-10-28 | 湖南科技大学 | Detecting system based on concrete box girder bridge web-plate vertical pre-stressed reinforcing steel tensioning force |
| CN204255818U (en) * | 2014-10-15 | 2015-04-08 | 浙江大学 | For the pilot system of the information acquisition of concrete surface Initial Cracking and identification |
| CN106932441A (en) * | 2017-03-17 | 2017-07-07 | 青岛理工大学 | The corrosion part and test device and method of testing in prefabricated crack |
| CN106932338A (en) * | 2017-04-11 | 2017-07-07 | 青岛理工大学 | Extravasation electricity accelerates steel bar corrosion test device and building method |
| CN107843554A (en) * | 2017-12-08 | 2018-03-27 | 信阳师范学院 | A kind of reinforced concrete interface bond stress test device and preparation method |
| CN208076066U (en) * | 2018-04-17 | 2018-11-09 | 青岛理工大学 | A kind of testing mould of Corroded Reinforced Concrete |
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