CN115372404A - Concrete chloride ion migration measuring system and measuring method - Google Patents

Abstract

The application provides a concrete chloride ion migration measurement system and a measurement method, and relates to the technical field of measurement, wherein the measurement system comprises a temperature control device and a migration experiment device, the temperature control device comprises a freeze-thaw test box and a temperature adjusting mechanism, the freeze-thaw test box is provided with an accommodating cavity, and the temperature adjusting mechanism is used for adjusting and controlling the environment temperature in the accommodating cavity so as to simulate the freeze-thaw cycle process; the migration experimental apparatus is arranged in the accommodating cavity and used for carrying out concrete chloride ion electromigration experiments. The measurement system and the measurement method can obtain the unsteady state migration coefficient of the chloride ions in the cooling process, have wide application range and strong operability, and can meet the research requirement of the concrete durability in frozen soil areas, and the obtained chloride ion transmission coefficient has high reliability.

Description

Concrete chloride ion migration measuring system and measuring method

Technical Field

The invention relates to the technical field of measurement, in particular to a concrete chloride ion migration measurement system and a measurement method.

Background

At present, in some seasonal frozen saline soil areas, due to large day-night temperature difference, the seasonal frozen soil is widely distributed, the soil body salinization phenomenon is serious, and the problem of durability of a concrete structure in the areas is increasingly prominent in a severe environment; for example, in ocean engineering, seawater contains a large amount of corrosive ions, so that the service life of a concrete building is rapidly reduced due to seawater scouring in the season change process, and repeated freeze thawing and salt erosion are main causes of structural damage. Considering that the concrete freeze-thaw damage is caused by hydrostatic pressure generated in the migration process of unfrozen water due to freezing and expansion of water, the salt corrosion is mainly caused by chemical reaction of chloride ions and reinforcing steel bars, so that the interface between the reinforcing steel bars and cement paste falls off, and although the damage mechanisms of the chloride ions and the reinforcing steel bars are different, the transmission of water or corrosion ions cannot be separated. Therefore, the problem of concrete durability in the frozen soil area can be effectively improved by knowing the transmission rule of the chloride ions. Although the prior art provides a method for testing the transmission coefficient of chloride ions in concrete, the measurement method of the prior art has low reference value of the obtained chloride ion transmission data, and cannot meet the research requirement of the durability of concrete in frozen soil areas.

Disclosure of Invention

The invention aims to provide a concrete chloride ion migration measuring system and a measuring method of the concrete chloride ion migration measuring system, which can obtain the unsteady state migration coefficient of chloride ions in the cooling process, have wide application range and strong operability, obtain the chloride ion transmission coefficient with high reliability, and can meet the research requirement of the concrete durability in frozen soil areas.

The embodiment of the invention is realized by the following steps:

in a first aspect, the present invention provides a concrete chloride ion migration measurement system, comprising:

the temperature control device comprises a freeze-thaw test box and a temperature regulating mechanism, the freeze-thaw test box is provided with a containing cavity, and the temperature regulating mechanism is used for regulating and controlling the environmental temperature in the containing cavity so as to simulate the freeze-thaw cycle process; the migration experimental device is arranged in the containing cavity and used for carrying out concrete chloride ion electromigration experiments.

In an optional embodiment, the migration experiment device comprises a box body, a positioning assembly, a positive plate and a negative plate, wherein the box body is provided with a first chamber and a second chamber which are independent of each other, the positioning assembly is connected with the box body, and the positioning assembly is used for positioning a concrete sample and can enable the concrete sample to be horizontally arranged; the positive plate and the negative plate are connected with the positioning assembly and are respectively attached to the concrete sample.

In an alternative embodiment, the box body comprises a bottom shell, a partition plate and a cover plate, wherein the partition plate is connected with the bottom shell to divide the bottom shell into two independent grooves, the cover plate is connected with the bottom shell, and the cover plate blocks the notches of the two grooves, so that the cover plate, the bottom shell and the partition plate jointly define the first chamber and the second chamber;

the positioning assembly is connected with the partition plate.

In an optional embodiment, the cover plate is provided with two first positioning holes corresponding to the first chamber and two second positioning holes corresponding to the second chamber, one of the two first positioning holes is internally inserted with a temperature probe, and the other one of the two first positioning holes is internally used for being penetrated with a lead connected with the positive plate; one of the two second positioning holes is inserted with the temperature probe, and the other one is internally used for penetrating a lead connected with the negative plate.

In an alternative embodiment, the positioning assembly includes a positioning sleeve and two anchor ears, the positioning sleeve penetrates through the partition plate and is connected with the partition plate in a sealing manner, and two ends of the positioning sleeve are respectively located in the first chamber and the second chamber; the cylinder cavity of the positioning sleeve is used for inserting a concrete sample; the two anchor ears are sleeved outside the positioning sleeve and positioned on two sides of the partition plate;

the positive plate and the negative plate are both connected with the positioning sleeve.

In an optional embodiment, a first clamping groove is formed in one end of the positioning sleeve, and a part of the positive plate is embedded in the first clamping groove and is convexly arranged on the outer peripheral surface of the positioning sleeve; the other end of the positioning sleeve is provided with a second clamping groove, and the part of the negative plate is embedded in the second clamping groove and is convexly arranged on the peripheral surface of the positioning sleeve.

In an optional embodiment, the positioning assembly further includes a first limiting member and a second limiting member, the first limiting member and the second limiting member are both connected to the positioning sleeve and located outside the cylinder cavity of the positioning sleeve, the first limiting member abuts against the positive plate to cooperate with the bottom wall of the first clamping groove to clamp the positive plate, so as to limit the positive plate from being far away from the negative plate; the second limiting piece is abutted against the negative plate to be matched with the bottom wall of the second clamping groove to clamp the negative plate, so that the negative plate is limited to be far away from the positive plate;

the negative plate and the positive plate are used for clamping a concrete sample.

In an optional embodiment, the number of the first card slots and the number of the second card slots are both multiple, the multiple first card slots are arranged in the circumferential direction of the positioning sleeve, and the multiple second card slots are arranged in the circumferential direction of the positioning sleeve; the positive plates are embedded in the first clamping grooves, and the negative plates are embedded in the second clamping grooves;

the first limiting part and the second limiting part are both arranged to be annular structures.

In an optional embodiment, the temperature control device further includes a test piece box and a temperature probe, the test piece box is used for placing a reference test piece, and the temperature probe is used for acquiring the temperature of the reference test piece.

In a second aspect, the present invention provides a measurement method based on the concrete chloride ion migration measurement system according to any one of the preceding embodiments, the measurement method including:

preparing a concrete sample and a reference test piece;

positioning the concrete sample in the migration experiment device, and positioning the reference test piece in the freeze-thaw test box;

and (3) simulating a freeze-thaw cycle process in the accommodating cavity by using the temperature regulating mechanism, and carrying out a chloride ion electromigration experiment on the concrete sample by using the migration experiment device in the process.

The embodiment of the invention has the beneficial effects that:

to sum up, the concrete chloride ion migration measurement system that this embodiment provided fixes a position the concrete sample on the migration experimental apparatus, utilizes the migration sample device to carry out the chloride ion electromigration experiment. Meanwhile, in the experimental process, the temperature adjusting mechanism is controlled to adjust the ambient temperature in the accommodating cavity, so that the ambient temperature of the concrete sample is adjusted, the freezing and thawing cycle process is simulated, the test environment is more consistent with the actual environment of the concrete structure in the frozen soil area, namely, in the running process of the measuring system, the temperature reduction rate and the temperature range can be adjusted by means of the temperature adjusting mechanism, the unsteady state migration coefficient of the concrete sample under the set low-temperature condition can be calculated by means of electromigration test, and finally, a plurality of groups of test results are compared to obtain the transmission performance change rule of chloride ions in the concrete in the temperature change process, the experimental data are closer to the change condition of the on-site concrete, and the research requirement on the concrete durability in the frozen soil area can be met.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and those skilled in the art can also obtain other related drawings based on the drawings without inventive efforts.

FIG. 1 is a schematic structural diagram of a concrete chloride ion migration measurement system according to an embodiment of the present invention;

FIG. 2 is an exploded view of a migration experiment apparatus according to an embodiment of the present invention;

FIG. 3 is a schematic cross-sectional view of a migration experiment apparatus according to an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a case according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a matching structure of the positioning assembly, the positive plate and the negative plate according to the embodiment of the invention;

fig. 6 is an exploded structural schematic diagram of the positioning assembly, the positive plate and the negative plate according to the embodiment of the invention.

Icon:

001-concrete sample; 002-reference test piece; 003-anodic solution; 004-cathode solution; 005-refrigerating fluid; 100-a temperature control device; 110-freeze-thaw test chamber; 111-a housing chamber; 120-a temperature regulating mechanism; 130-a first bracket; 140-a second support; 150-a test piece box; 160-temperature measuring probe; 170-limiting line; 200-migration experimental setup; 210-a box body; 211-a bottom shell; 2111-first groove; 2112-second groove; 212-a separator; 2121-fitting a through hole; 213-cover plate; 2131-a first locating hole; 2132-second locating holes; 214-a first sealing ring; 215-a second sealing ring; 216-a handle; 220-a positioning assembly; 221-a positioning sleeve; 2211-a first card slot; 2212-second card slot; 222-a hoop; 223-a first limiting member; 224-a second stop; 230-positive plate; 231-a first clamping part; 232-a first circular fitting; 240-negative plate; 241-a second clamping part; 242 — second circular fit.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or the orientations or positional relationships that the products of the present invention are conventionally placed in use, and are only used for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

Furthermore, the terms "horizontal", "vertical" and the like do not imply that the components are absolutely horizontal or hanging, but may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As one of widely used building materials, the durability of the reinforced concrete directly determines the service life of a building structure and restricts the economic development benefit of the society. In actual engineering, factors influencing the durability of concrete are many, but researches show that the corrosion of chloride ions to the concrete is a main cause of corrosion of reinforcing steel bars. For example, in projects such as roads, railway bridges, saline-alkali lands, deicing salt roads and bridges in coastal areas of China, the service life of a reinforced concrete structure is rapidly reduced due to long-term contact with a chloride ion solution, so that the study on the transmission characteristics of chloride ions in concrete has important significance for enhancing the durability of reinforced concrete and predicting the service life of the structure. Although the prior art already describes a method for testing the transmission coefficient of chloride ions in concrete, the prior art is based on room temperature conditions, and does not consider the influence of environmental factors such as temperature change or low-temperature icing on the experimental process and experimental results, and the chloride ion transmission coefficient obtained according to the prior art cannot be used alone as a reference basis for the chloride ion transmission performance in a freeze-thaw environment. That is to say, in a frozen soil area, the environment where the concrete structure is located is complicated and changeable, the temperature environment changes greatly, and the concrete structure is in a freeze-thaw cycle environment for a long time, the test method in the prior art does not consider the influence of the complicated and changeable temperature environment on the transmission coefficient of the chloride ions, and the experimental data obtained by the test method in the prior art cannot be used as the reference basis for the chloride ion transmission performance in the freeze-thaw environment.

In view of this, designers have designed a concrete chloride ion migration measurement system, and the temperature environment in the concrete experiment process is fully considered, so that the unsteady state migration coefficient of chloride ions in the cooling process can be obtained, and the system has the advantages of wide application range and strong operability.

Referring to fig. 1, in the present embodiment, the concrete chloride ion migration measurement system includes a temperature control device 100 and a migration experiment device 200, the temperature control device 100 includes a freezing and thawing test box 110 and a temperature adjustment mechanism 120, the freezing and thawing test box 110 is provided with an accommodating chamber 111, and the temperature adjustment mechanism 120 is used for adjusting and controlling an ambient temperature in the accommodating chamber 111 to simulate a freezing and thawing cycle process; the migration experimental device 200 is arranged in the accommodating cavity 111, and the migration experimental device 200 is used for performing a concrete chloride ion electromigration experiment.

It should be noted that, in the measurement system provided in this embodiment, during operation, the concrete sample 001 is positioned on the migration experiment apparatus 200, and the migration experiment apparatus is used to perform the chloride electromigration experiment. Meanwhile, in the experimental process, the environmental temperature in the accommodating cavity 111 can be adjusted by controlling the temperature adjusting mechanism 120, so that the environmental temperature of the concrete sample 001 can be adjusted, the freezing and thawing cycle process can be effectively simulated, and the test environment in the test process of the concrete sample 001 is closer to the actual environment of the concrete structure in the frozen soil region. That is to say, in the operation process of the measuring system, the temperature reduction rate and the temperature range can be adjusted by means of the temperature adjusting mechanism 120, the unsteady state migration coefficient of the concrete sample 001 under the set low temperature condition can be calculated through an electromigration test, and finally, the transmission performance change rule of chloride ions in the concrete in the temperature change process is obtained by comparing a plurality of groups of test results, the experimental data is closer to the change condition of the on-site concrete, and the research requirement on the concrete durability in the frozen soil area can be met.

Referring to fig. 1, in this embodiment, optionally, the freeze-thaw test chamber 110 is provided with a square shell, the top of the freeze-thaw test chamber 110 is open, and the bottom of the freeze-thaw test chamber 110 is closed, a first bracket 130 and a second bracket 140 are installed on an inner bottom wall of the freeze-thaw test chamber 110, and both the first bracket 130 and the second bracket 140 may be provided as metal brackets. The first bracket 130 and the second bracket 140 can be fixed on the freeze-thaw test chamber 110 by welding, and openings for fixing the brackets do not need to be arranged on the freeze-thaw test chamber 110, so that the integrity of the freeze-thaw test chamber 110 is not damaged, and the tightness of the bottom of the freeze-thaw test chamber 110 is not easily reduced. Meanwhile, the outer wall of the freeze-thaw test box 110 can be provided with an insulation board, so that the insulation performance of the freeze-thaw test box 110 is enhanced. Further, the inner wall of the freeze-thaw test chamber 110 is provided with a limit line 170, and the limit line 170 is used as a reference line for the liquid storage amount in the accommodating cavity 111.

Optionally, during temperature adjustment, a certain amount of refrigerating fluid 005 is stored in the accommodating cavity 111 of the freeze-thaw test box 110, and the storage amount of the refrigerating fluid 005 does not exceed the limit line 170. The temperature of the cooling fluid 005 may then be adjusted as needed to simulate the temperature environment in which the migration experiment apparatus 200 is located. It should be understood that the temperature control device 100 may be referred to a freeze-thaw tester of the prior art, and the structure and principle thereof are not specifically described in this embodiment in order to avoid repetitive drag.

Meanwhile, the temperature control device 100 further comprises a test piece box 150 and a temperature measuring probe 160, wherein the test piece box 150 is placed on the second support 140, and the second support 140 is used for fixing the position. For example, the specimen box 150 is closed at the bottom and opened at the top, and the specimen box 150 is used to position the reference specimen 002. After the reference test piece 002 is placed in the test piece box 150, the temperature measuring probe 160 is inserted into the reference test piece 002, and the temperature measuring probe 160 is used for acquiring the real-time temperature of the reference test piece 002, and the real-time temperature can be used as the reference temperature for temperature adjustment of the refrigerating fluid 005.

Referring to fig. 2 to fig. 3, in the present embodiment, optionally, the migration experiment apparatus 200 includes a box 210, a positioning assembly 220, a positive electrode sheet 230, and a negative electrode sheet 240. The box 210 is a closed structure, the positioning assembly 220 is used for positioning the concrete sample 001, the positioning assembly 220 is located in the box 210, and the positive plate 230 and the negative plate 240 are both connected with the positioning assembly 220 and can be connected with an external power supply. In operation, the positive electrode tab 230 and the negative electrode tab 240 are respectively attached to both end faces of the concrete sample 001.

Referring to fig. 4, optionally, the box body 210 includes a square bottom case 211, a square partition 212 and a square cover 213, the bottom of the bottom case 211 is closed, the top of the bottom case 211 has an opening, the partition 212 is fixed in the bottom case 211, the partition 212 partitions the bottom case 211 into a first recess 2111 and a second recess 2112 which are independent of each other, the notches of the first recess 2111 and the second recess 2112 face the top of the bottom case 211, and the volumes of the first recess 2111 and the second recess 2112 are equal. That is, the inner cavity of the bottom case 211 is equally divided into two grooves by the partition 212. Meanwhile, the partition 212 is provided with an assembling through hole 2121, the assembling through hole 2121 is a circular through hole, the assembling through hole 2121 is parallel to the bottom of the bottom case 211, the bottom of the bottom case 211 is supported on the first support 130, and an axis of the assembling through hole 2121 extends horizontally during the experiment. A cover plate 213 is provided at the top of the bottom case 211, and the cover plate 213 can be opened to be separated from the bottom case 211. After the cover plate 213 is assembled with the bottom cover 211, the cover plate 213 can simultaneously close the notches of the first and second recesses 2111 and 2112, that is, the cover plate 213 is hermetically connected with the bottom cover 211 and the partition 212, so that the first recess 2111 forms a closed first chamber and the second recess 2112 forms a closed second chamber. Due to the structural design of the cover plate 213, impurities can be prevented from entering the bottom case 211, thereby affecting the experimental result.

Further, the cover plate 213 is provided with two first positioning holes 2131 and two second positioning holes 2132, when the cover plate 213 is connected to the bottom case 211, the two first positioning holes 2131 are both communicated with the first chamber, and the two second positioning holes 2132 are both communicated with the second chamber. A temperature probe is inserted into one of the two first positioning holes 2131, and the other of the two first positioning holes 2131 is used for passing through a lead connected with the positive plate 230. One of the two second positioning holes 2132 is inserted with a temperature probe, and the other of the two second positioning holes 2132 is used for penetrating a lead connected with the negative plate 240. It should be appreciated that the positioning of the temperature probes and wires by the cover 213 results in a compact, small footprint and convenient use of the overall device.

It should be noted that the first positioning hole 2131 and the second positioning hole 2132 may be circular holes.

Further, a handle 216 is disposed on the top of the cover plate 213 for facilitating the assembly and disassembly of the cover plate 213. Meanwhile, the bottom of the cover plate 213 is provided with two sealing rings, and the two sealing rings are respectively used for sealing the periphery of the first chamber and the periphery of the second chamber. That is, when the cover plate 213 is assembled with the bottom case 211, the first sealing ring 214 is in sealing contact with the partition plate 212 and the inner wall of the bottom case 211 to form an annular sealing area. Similarly, the second sealing ring 215 is in sealing contact with the partition 212 and the inner wall of the bottom case 211 to form an annular sealing area.

Referring to fig. 5 and fig. 6, optionally, the positioning assembly 220 includes a positioning sleeve 221, two anchor ears 222, a first limiting member 223 and a second limiting member 224. The positioning sleeve 221 is a cylindrical tube, the positioning sleeve 221 is inserted into the assembling through hole 2121 of the partition 212, and the positioning sleeve 221 is divided by the partition 212, i.e. the length of the positioning sleeve 221 extending into the first chamber is the same as the length of the positioning sleeve 221 extending into the second chamber. The two anchor ears 222 are sleeved outside the positioning sleeve 221 and located at two sides of the partition 212. The positioning sleeve 221 has a first end and a second end in the axial direction, the first end is provided with two first clamping grooves 2211 arranged in a central symmetry manner, and the second end is provided with two second clamping grooves 2212 arranged in a central symmetry manner. The positive plate 230 includes two first clamping portions 231 and a first circular attaching portion 232 located between the two first clamping portions 231, the two first clamping portions 231 are located on the same diameter of the first circular attaching portion 232, the two first clamping portions 231 are respectively clamped in the two first clamping grooves 2211, the two first clamping portions 231 all protrude out of the outer peripheral surface of the positioning sleeve 221, and one of the first clamping portions 231 is used for being connected with a wire. The first circular bonding portion 232 is used for bonding to one end surface of the concrete sample 001. Similarly, the negative electrode plate 240 includes two second clamping portions 241 and a second circular attaching portion 242 located between the two second clamping portions 241, the two second clamping portions 241 are located on the same diameter of the second circular attaching portion 242, the two second clamping portions 241 are clamped in the two second clamping slots 2212, the two second clamping portions 241 protrude outwards from the outer peripheral surface of the positioning sleeve 221, and one of the clamping portions is used for being connected with a wire. The second circular fitting portion 242 is used for fitting one end surface of the concrete sample 001.

Optionally, the first limiting member 223 and the second limiting member 224 are both set to be elastic rings, the first limiting member 223 and the second limiting member 224 are both sleeved outside the positioning sleeve 221, the first limiting member 223 is abutted to one side of the two first clamping portions 231, which is far away from the negative plate 240, so that the positive plate 230 is clamped between the bottom wall of the first clamping groove 2211 and the first limiting member 223, and the positive plate 230 is limited to be far away from the negative plate 240, so that the positive plate 230 can be better attached to one end surface of the concrete sample 001. Second locating part 224 keeps away from one side butt of positive plate 230 with two second joint portions 241 simultaneously, make negative pole piece 240 by the centre gripping between the tank bottom wall of second locating part 224 and second draw-in groove 2212, limit negative pole piece 240 and keep away from positive plate 230, thereby make the laminating that negative pole piece 240 can be better on the another terminal surface of concrete sample 001, thus, in the experimentation, positive plate 230 and negative pole piece 240 are difficult for floating for concrete sample 001 in the freeze-thaw process, positive plate 230 and negative pole piece 240 can remain the position of laminating with concrete sample 001 all the time, be difficult for influencing the chloridion migration, guarantee the quick migration effect of chloridion, make the experimental result more accurate. Moreover, the first limiting member 223 and the second limiting member 224 are elastic rings, and the positive plate 230 and the negative plate 240 are tightly abutted by elasticity, so that the adjustment is convenient, the flexibility is strong, and the disassembly and assembly are convenient.

Note that the spacer 212 may be provided as an epoxy board. The positioning sleeve 221 may be provided as a silicone rubber sleeve.

Further, the number of the first card slot 2211 and the second card slot 2212 is not limited to two, and the number of the first card slot 2211 and the second card slot 2212 may also be one, three, five, or the like. Meanwhile, the number of the first clamping portions 231 on the positive electrode sheet 230 may be equal to and correspond to the number of the first clamping slots 2211, and the number of the second clamping portions 241 on the negative electrode sheet 240 may be equal to and correspond to the number of the second slots.

In addition, the first limiting member 223 and the second limiting member 224 may also be an annular structure such as a snap ring.

Note that the first chamber is used for storing the anode solution 003, and the second chamber is used for storing the cathode.

Referring to fig. 1 to fig. 6, the present embodiment further provides a measurement method based on a concrete chloride ion migration measurement system, the method includes the following steps:

step S100, preparing a concrete sample 001 and a reference sample 002;

optionally, the steps of preparing the concrete sample 001 and preparing the reference sample 002 are substantially the same, and the difference between the steps lies in that a preformed groove needs to be formed at the end of the reference sample 002 in the preparation process of the reference sample 002 for positioning the temperature measuring probe 160, and the specific steps include, for example:

1. a cylindrical test piece with the diameter (100 +/-2) mm and the height (100 +/-2) mm is adopted;

2. when a test piece is manufactured in a laboratory, the maximum nominal grain diameter of the aggregate is not more than 30mm and the aggregate is used

The mold is tested, so that later cutting can be avoided, and microcracks can not be generated in the concrete block due to cutting; meanwhile, the manufacturing error of the reference test piece 002 with the positioning temperature measuring probe 160 can be reduced;

3. placing the reference test piece 002 in front of a vibrating table, inserting a cylindrical steel bar with the diameter of 10mm into the center of a sample, wherein the distance between the steel bar and the bottom surface of the reference test piece 002 is (50 +/-2) mm, and in the process of standing the reference test piece 002, slightly rotating the cylindrical steel bar every 1h until the cylindrical steel bar is pulled out after (12 +/-1) h, so that a reserved groove is formed at one end of the reference test piece 002;

4. all test pieces should be demolded within (24 ± 2) h and then placed in a standard curing room at 25 ℃ with 98% rh;

5. the maintenance age of the test piece is preferably 28d, and 56d or 84d can be selected according to the design requirements.

6. After the age reached 28 days, the test pieces were taken out of the curing room, and the water on the surfaces of the test pieces was wiped off with a clean rag. The diameter and height of the test piece are measured using a vernier caliper to the nearest 0.1mm. And then carrying out saturation treatment on the test piece by adopting the prior known technology.

Step S200, positioning the concrete sample 001 in the migration experiment device 200, and positioning the reference test piece 002 in the freeze-thaw test box 110, specifically as follows:

1. before the concrete sample 001 is installed in the positioning sleeve 221, the concrete sample is blown dry by an electric blowing air-cooling wind shield, the surface is clean, and oil stains, sand and water drops do not exist;

2. before the test, the bottom shell 211 is washed clean by cold boiled water at room temperature;

3. the processed concrete sample 001 is loaded in the middle position of the positioning sleeve 221, then the melted paraffin is smeared at the hole of the middle clapboard 212 of the test groove, then the positioning sleeve 221 with the concrete sample 001 horizontally passes through the assembly through hole 2121 of the clapboard 212, and two stainless steel hoops 222 are arranged on the outer side of the positioning sleeve 221. The height of each hoop is designed to be about 20mm, the hoop 222 is screwed outside the positioning sleeve 221, the sealing performance between the positioning sleeve 221 and the concrete sample 001 is improved, and the condition that chloride ions penetrate through a gap between the positioning sleeve 221 and the concrete sample 001 is reduced or eliminated, so that the error of an experimental result is reduced;

4. vaseline can be coated on the outer peripheral surface of the concrete sample 001 to further ensure the sealing property;

5. after the concrete sample 001 is arranged on the positioning sleeve 221 and fixed by the hoop 222, secondarily smearing paraffin on the joint of the positioning sleeve 221 and the partition plate 212, and repeatedly winding the joint by using a water stop after the paraffin is solidified;

6. the positive plate 230 and the negative plate 240 are respectively clamped at two ends of the positioning sleeve 221, so that the positive plate 230 and the negative plate 240 are attached to two end faces of the concrete sample 001, the first limiting member 223 and the second limiting member 224 are sleeved outside the positioning sleeve 221, the positive plate 230 and the negative plate 240 are fixed, and the positive plate 230 and the negative plate 240 are prevented from floating relative to the concrete sample 001. Then, about 10L of NaOH solution with a concentration of 0.3mol/L was injected into the first chamber, and the positive electrode sheet 230 and the concrete sample 001 were both immersed in the solution. Injecting 10L of NaCl solution with the mass concentration of 10% into the second chamber, wherein the liquid levels in the first chamber and the second chamber are flush;

7. after the two-electrode solution is injected, the positive electrode of the dc voltage-stabilized power supply should be connected to the positive electrode tab 230 by a lead wire, and the negative electrode should be connected to the negative electrode tab 240 by a lead wire. The lead wire connected with the positive plate 230 passes through the first positioning hole 2131 on the cover plate 213, and the lead wire connected with the negative plate 240 passes through the second positioning hole 2132 on the cover plate 213;

step S300, simulating a freeze-thaw cycle process in the accommodating cavity 111 by using the temperature adjustment mechanism 120, that is, performing a freeze-thaw cycle experiment, and performing a chloride electromigration experiment on the concrete sample 001 by using the migration experiment apparatus 200 in the process, where it should be noted that the electromigration experiment and the freeze-thaw cycle experiment are performed simultaneously, and the step of the electromigration experiment refers to the prior art.

Specific steps of the freeze-thaw cycle experiment include, for example:

1. after the maintenance age of the reference test piece 002 reaches 28d, taking out the reference test piece 002 from the maintenance room, cleaning the inner side of the preformed groove by using a slender suction pipe brush, wiping the water on the surface of the reference test piece 002 by using a clean rag, and then performing saturation treatment on the reference test piece 002, wherein the prior known technology is referred for the saturation treatment;

2. the reference specimen 002 is placed in the specimen box 150, and the specimen box 150 is placed in the freezing liquid 005. The distance between the bottom surface of the test piece box 150 and the ground of the freeze-thaw test box 110 is at least 20mm, and the freezing liquid 005 is ensured not to exceed the limit line 170 of the accommodating cavity 111.

3. The temperature measuring probe 160 is inserted into the preformed groove of the reference test piece 002, and the two temperature probes are respectively inserted into the first positioning hole 2131 and the second positioning hole 2132 and are completely immersed into the anode solution 003 and the cathode solution 004.

4. The cycling temperature is set between 20 ℃ and-5 ℃, the cycling time is determined according to the time of an electromigration experiment, the time for thawing is not less than 1/4 of the total freezing-thawing time, and the switching time between freezing and thawing is not more than 10min.

The concrete chloride ion migration measurement system and the concrete chloride ion migration measurement method provided by the embodiment have the following advantages:

the measurement deviation caused by the temperature change of the freezing point is reduced, the migration effect of chloride ions is improved, the floating problem of the anode plate in the prior art is solved, and meanwhile, the operability is high; by adding the temperature control device 100, the control of the circulating temperature and time is realized, so that the embodiment of the application can be used for rapid chloride ion determination at normal temperature and is also suitable for electromigration experiments in the freezing-thawing circulating process, namely the applicability is wider; the temperature control device 100 and the migration experiment device 200 are matched for use, so that the requirement of simultaneous implementation of an electromigration experiment and a freeze-thaw experiment is met, the chloride ion transmission coefficient of concrete in the freezing process is obtained, and a reference basis is provided for the experiment of the transmission performance of the concrete in the frozen soil area.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A concrete chloride ion migration measurement system, comprising:

the temperature control device comprises a freeze-thaw test box and a temperature regulating mechanism, the freeze-thaw test box is provided with a containing cavity, and the temperature regulating mechanism is used for regulating and controlling the environmental temperature in the containing cavity so as to simulate the freeze-thaw cycle process; the migration experimental device is arranged in the containing cavity and used for carrying out concrete chloride ion electromigration experiments.

2. The concrete chloride ion migration measurement system according to claim 1, wherein:

the migration experiment device comprises a box body, a positioning assembly, a positive plate and a negative plate, wherein the box body is provided with a first cavity and a second cavity which are mutually independent, the positioning assembly is connected with the box body, and the positioning assembly is used for positioning a concrete sample and can horizontally arrange the concrete sample; the positive plate and the negative plate are connected with the positioning assembly and are respectively attached to the concrete sample.

3. The concrete chloride ion migration measurement system of claim 2, wherein:

the box body comprises a bottom shell, a partition plate and a cover plate, the partition plate is connected with the bottom shell to divide the bottom shell into two independent grooves, the cover plate is connected with the bottom shell, and the cover plate blocks the notches of the two grooves, so that the cover plate, the bottom shell and the partition plate jointly define a first chamber and a second chamber;

the positioning assembly is connected with the partition plate.

4. The concrete chloride ion migration measurement system of claim 3, wherein:

the cover plate is provided with two first positioning holes corresponding to the first cavity and two second positioning holes corresponding to the second cavity, one of the two first positioning holes is internally inserted with a temperature probe, and the other one of the two first positioning holes is internally used for penetrating a lead connected with the positive plate; one of the two second positioning holes is inserted with the temperature probe, and the other one is internally used for penetrating a lead connected with the negative plate.

5. The concrete chloride ion migration measurement system of claim 3, wherein:

the positioning assembly comprises a positioning sleeve and two hoops, the positioning sleeve penetrates through the partition plate and is in sealed connection with the partition plate, and two ends of the positioning sleeve are respectively positioned in the first cavity and the second cavity; the cylinder cavity of the positioning sleeve is used for inserting a concrete sample; the two anchor ears are sleeved outside the positioning sleeve and positioned on two sides of the partition plate;

the positive plate and the negative plate are both connected with the positioning sleeve.

6. The concrete chloride ion migration measurement system of claim 5, wherein:

a first clamping groove is formed in one end of the positioning sleeve, and part of the positive plate is embedded in the first clamping groove and is convexly arranged on the peripheral surface of the positioning sleeve; the other end of the positioning sleeve is provided with a second clamping groove, and the part of the negative plate is embedded in the second clamping groove and is convexly arranged on the peripheral surface of the positioning sleeve.

7. The concrete chloride ion migration measurement system of claim 6, wherein:

the positioning assembly further comprises a first limiting piece and a second limiting piece, the first limiting piece and the second limiting piece are connected with the positioning sleeve and located outside a cylinder cavity of the positioning sleeve, and the first limiting piece is abutted against the positive plate to be matched with the bottom wall of the first clamping groove to clamp the positive plate, so that the positive plate is limited from being far away from the negative plate; the second limiting piece is abutted against the negative plate to be matched with the bottom wall of the second clamping groove to clamp the negative plate, so that the negative plate is limited to be far away from the positive plate;

the negative plate and the positive plate are used for clamping a concrete sample.

8. The concrete chloride ion migration measurement system of claim 7, wherein:

the number of the first clamping grooves and the number of the second clamping grooves are multiple, the first clamping grooves are distributed in the circumferential direction of the positioning sleeve, and the second clamping grooves are distributed in the circumferential direction of the positioning sleeve; the positive plates are embedded in the first clamping grooves, and the negative plates are embedded in the second clamping grooves;

the first limiting part and the second limiting part are both arranged to be annular structures.

9. The concrete chloride ion migration measurement system of claim 1, wherein:

the temperature control device further comprises a test piece box and a temperature probe, wherein the test piece box is used for placing a reference test piece, and the temperature probe is used for acquiring the temperature of the reference test piece.

10. A measuring method based on the concrete chloride ion migration measuring system according to any one of claims 1 to 9, characterized in that the measuring method comprises:

preparing a concrete sample and a reference test piece;

positioning the concrete sample in the migration experiment device, and positioning the reference test piece in the freeze-thaw test box;

and (3) simulating a freeze-thaw cycle process in the accommodating cavity by using the temperature regulating mechanism, and carrying out a chloride ion electromigration experiment on the concrete sample by using the migration experiment device in the process.

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