A method for collecting chloride salt deposited on the surface of dense building walls

Abstract

The invention discloses a method for collecting chloride salt deposited on the surface of a dense wall of a building; the method comprises the steps of filling a sampling tube with pure water, storing the filled sampling tube, locating a sampling point, soaking a sampling head, applying the sample eight times, and labeling and storing the sample. The sampling method of the invention has the characteristics of convenient operation, high sampling efficiency and low cost, and can realize non-destructive and accurate sampling of chloride salt deposited on the surface of a dense wall of a building.

Description

Technical Field

[0001] The invention relates to a method for collecting chloride salt deposition, in particular to a method for collecting chloride salt deposition on the surface of a dense wall of a building. Background Art

[0002] Buildings serving in coastal environments are corroded by chloride salts. Chloride salts in the environment first deposit on the surface of the building, causing the exterior finish to fall off or crack, and then spread to the interior to induce steel corrosion, seriously affecting the durability and safety of the building structure. Knowing the deposition pattern of chloride salts on the surface of coastal buildings is the first step in preventing salt damage. At present, the surface of coastal building maintenance structures is mostly made of materials with small porosity and dense structure, such as marble, paint and various types of hanging panels.

[0003] Therefore, how to accurately measure the amount of chloride salt deposition on the surface of dense building walls is an urgent problem to be solved.

[0004] In view of the above problems, the prior art uses concrete as a sampling object and adopts a core sampling method or a powder sampling method to collect chloride salts deposited on the surface or inside of the concrete.

[0005] For example, the patent with publication number CN 212030964 U discloses a portable concrete on-site powder collection device. Compared with traditional sampling tools such as shovels and scalpels, this device has more precise control over the sampling location and sampling thickness; compared with core sampling, it integrates the sampling and grinding steps, making field sampling more efficient and convenient. However, this sampling method will inevitably cause damage to the sampling object. There is a lot of communication work that needs to be completed in advance before sampling, and the sampling location needs to be repaired after sampling. It is difficult to achieve sampling of chloride salts deposited on the surface of buildings in large-scale use. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings and deficiencies of the above-mentioned prior art and provide a method for collecting chloride salts deposited on the surface of dense wall of a building. The present invention can not only collect chloride salts deposited on the surface of the building wall without destroying the building, but also collect stable data with small error, which has practical significance for studying the corrosion of coastal buildings by chloride salts.

[0007] The present invention is achieved through the following technical solutions:

[0008] A method for collecting chloride salt deposited on the surface of a dense wall of a building comprises the following steps:

[0009] Step A: Filling the sample solution

[0010] Take pure water and fill it into the sampling tube;

[0011] Step B: Packing and shipping

[0012] Place the filled sampling tubes in a sampling tube storage box with multiple grids;

[0013] When placing the sampling tubes, do not place the sampling tubes in the first cell of the odd-numbered rows of the sampling tube storage box, and do not place the sampling tubes in the last cell of the even-numbered rows to avoid squeezing the sampling tubes. Then transport them to the experimental site.

[0014] Step C: Locate sampling points

[0015] At the experimental site, the building wall to be tested is located at a height of 1.2m-1.5m above the ground as the building wall sampling area;

[0016] Step D: Wetting the sampling head

[0017] At the experimental site, the flocked sampling swab was inserted into the sampling liquid in the sampling tube in step A to be immersed, and then slowly taken out to above the liquid level of the sampling liquid, and reciprocatedly hit the wall of the sampling tube four times to shake off the excess liquid, and finally slid out along the wall of the sampling tube to reduce the sampling liquid attached to the flocked sampling swab again, so that the flocked sampling swab was moist but not dripping;

[0018] Step E: Smear sampling

[0019] At the experimental site, a rectangular sampling specification plate is placed on the sampling area of ​​the building wall to be tested in step C, the four sides of the rectangular sampling specification plate are fixed and tightly attached to the sampling area of ​​the building wall to be tested, and the flocked sampling swab that is moistened but not dripping in step D is used to smear and sample eight times in the sampling area of ​​the building wall framed by the rectangular sampling specification plate;

[0020] Step F: Label and store

[0021] After completing step E, place the broken sampling head in the sampling tube; label the collected samples on the frosted part of the sampling tube wall and the sampling tube storage box, such as: building-orientation-parallel sample number; when storing the sampling tubes, leave one empty grid in each row in the sampling tube storage box, and place the samples in sequence for easy use later.

[0022] In the above step A, pure water is taken and poured into the sampling tube. Specifically, 10-15 ml of pure water with a resistivity of 18.2 MΩ·cm is taken at 22-25° C. and poured into the sampling tube.

[0023] During the filling of the sampling liquid in step A above, use a manual single-channel adjustable pipette to take 10-15 ml of pure water. The specific operation is to place the sampling tube on a four-decimal electronic balance and return it to zero, use a pipette to take pure water and inject it into the sampling tube, observe the balance reading, and use a dropper to add pure water drop by drop until two decimal places meet the requirements.

[0024] In the above step D, the flocked sampling swab used in the process of wetting the sampling head is an oral swab with a total rod length of 154 mm, a rod diameter of 2.38 mm, a flocked head length of 20 mm, a sampling head diameter of 5.36 mm, and a break point located 30.78 mm away from the end of the sampling head.

[0025] During the smear sampling process in step E above, use a moist flocked sampling swab in the right hand to smear the building wall framed by the inner frame of the rectangular sampling specification plate eight times, specifically:

[0026] Place the sampling head parallel to the framed building wall surface to be sampled, and perform a smear sampling from bottom to top;

[0027] Place the sampling head parallel to the framed building wall surface to be sampled, rotate the angle and perform secondary smear sampling from top to bottom;

[0028] Place the sampling head parallel to the framed building wall surface to be sampled, turn the angle and smear the sample three times from left to right;

[0029] Place the sampling head parallel to the framed building wall surface to be sampled, turn the angle and perform four smear samplings from right to left;

[0030] Place the sampling head on the framed building wall surface at an angle of 45° to the sampling surface, and perform the fifth round of smear sampling in a zigzag trajectory from bottom to top. During this period, the sampling head needs to be rotated in time;

[0031] Place the sampling head on the framed building wall surface at an angle of 45° to the sampling surface, and perform the sixth smear sampling in a zigzag trajectory from top to bottom. During this period, the sampling head needs to be rotated in time;

[0032] Place the sampling head on the framed building wall surface at an angle of 45° to the sampling surface, and perform the seventh round of smear sampling from left to right in a zigzag trajectory. During this period, the sampling head needs to be rotated in time;

[0033] Place the sampling head on the framed building wall at an angle of 45° to the sampling surface, and perform the eighth smear sampling back and forth from right to left in a zigzag trajectory. During this period, the sampling head needs to be rotated in time.

[0034] In the above step E, the thickness of the rectangular sampling specification plate is 1 mm;

[0035] The inner frame of the rectangular sampling specification plate is a square with a side length of 200 mm; the building wall area framed by the inner frame is the sampling area; when used, the rectangular sampling specification plate is tightly attached to the building wall to be tested to prevent gaps around the inner frame from causing leakage. The rectangular sampling specification plate is an acrylic plate.

[0036] Compared with the prior art, the present invention has the following advantages and effects:

[0037] During the filling of the sampling liquid in step A of the present invention, using pure water with high resistivity as the sampling liquid can not only ensure that there is no interference from chloride ions from other sources before sampling, but also meet the requirement that there are no metal cations in the process of detecting the chloride ion content using a C900 ion chromatograph after sampling.

[0038] During the boxing and transportation process in step B of the present invention, no sampling tube is placed in the first grid of the odd-numbered row of the sampling tube storage box (49 grids), and no sampling tube is placed in the last grid of the even-numbered row, so as to avoid the phenomenon that the sampling tubes are squeezed against each other.

[0039] During the infiltration sampling head process of step D of the present invention, the flocked sampling swab is inserted into the sampling liquid in the sampling tube in step A for infiltration, slowly taken out to above the liquid level of the sampling liquid, reciprocatedly collides with the sampling tube wall four times, and excess liquid is shaken off, and finally slides out along the tube wall of the sampling tube to reduce the sampling liquid attached to the flocked sampling swab again, so that the flocked sampling swab is wet but not dripping; experimental data show that when sampling is performed using the flocked sampling swab in a dry state, the sample amount obtained is lower than the theoretical value. When sampling is performed using the flocked sampling swab in this state, the sample will not be lost from the rectangular sampling specification plate and the sampling surface due to excessive sampling liquid, and the chloride ions on the sampling surface can also be collected by the flocked sampling swab.

[0040] In the smear sampling process of step E of the present invention, a wet flocked sampling swab is used in the right hand to smear and sample the building wall framed by the inner frame eight times on the inner frame of the rectangular sampling specification plate. The samples collected by eight different smear sampling methods have good consistency, high accuracy and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a schematic diagram of the structure of the rectangular sampling specification plate used in the present invention.

[0042] Figure 2 This is a schematic diagram of the structure of the flocked sampling swab used in the present invention.

[0043] Figure 3 This is a schematic diagram of eight smearing sampling steps in step E of the present invention.

[0044] Figure 4 This is an error analysis diagram used in actual experiments of the present invention. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below in conjunction with specific embodiments.

[0046] like Figure 1-4As shown, the present invention discloses a method for collecting chloride salt deposited on the surface of a dense wall of a building, which can be achieved by the following steps:

[0047] Step A: Filling the sample solution

[0048] Take pure water and fill it into the sampling tube;

[0049] The details are as follows: take pure water and pour it into the sampling tube. Specifically, take 10-15ml of pure water with a resistivity of 18.2MΩ·cm under the condition of 22-25℃ and pour it into the sampling tube. Specific operation: use a manual single-channel adjustable pipette to take 10-15ml of pure water; place the sampling tube in a four-decimal electronic balance to zero, use a pipette to take pure water and inject it into the sampling tube, observe the balance reading, and use a dropper to add pure water drop by drop until the two decimal places meet the requirements. The specific conditions can be determined according to the specific environmental conditions.

[0050] Step B: Packing and shipping

[0051] Place the filled sampling tubes in a sampling tube storage box with multiple grids;

[0052] When placing the sampling tubes, do not place the sampling tubes in the first cell of the odd-numbered rows of the sampling tube storage box, and do not place the sampling tubes in the last cell of the even-numbered rows to avoid squeezing the sampling tubes. Then transport them to the experimental site.

[0053] Step C: Locate sampling points

[0054] At the experimental site, the building wall to be tested, at a height of 1.2m-1.5m from the ground, is used as the building wall sampling area; the actual sampling height and area can be determined according to the specific environmental conditions.

[0055] Step D: Wetting the sampling head

[0056] At the experimental site, the flocked sampling swab was inserted into the sampling liquid in the sampling tube in step A to be immersed, and then slowly taken out to above the liquid level of the sampling liquid, and reciprocatedly hit the wall of the sampling tube four times to shake off the excess liquid, and finally slid out along the wall of the sampling tube to reduce the sampling liquid attached to the flocked sampling swab again, so that the flocked sampling swab was moist but not dripping;

[0057] The flocked sampling swab used is an oral swab, with a total rod length of 154mm, a rod diameter of 2.38mm, a flocked head length of 20mm, a sampling head diameter of 5.36mm, and a break point located 30.78mm from the end of the sampling head. The actual specifications can be determined according to specific requirements.

[0058] Step E: Smear sampling

[0059] At the experimental site, a rectangular sampling specification plate is placed on the sampling area of ​​the building wall to be tested in step C, the four sides of the rectangular sampling specification plate are fixed and tightly attached to the sampling area of ​​the building wall to be tested, and the flocked sampling swab that is moistened but not dripping in step D is used to smear and sample eight times in the sampling area of ​​the building wall framed by the rectangular sampling specification plate;

[0060] During the collection, use a moist flocked sampling swab to apply eight smears to the building wall framed by the inner frame of the rectangular sampling specification plate. The specific steps are:

[0061] Place the sampling head parallel to the framed building wall surface to be sampled, and perform a smear sampling from bottom to top;

[0062] Place the sampling head parallel to the framed building wall surface to be sampled, rotate the angle and perform secondary smear sampling from top to bottom;

[0063] Place the sampling head parallel to the framed building wall surface to be sampled, turn the angle and smear the sample three times from left to right;

[0064] Place the sampling head parallel to the framed building wall surface to be sampled, turn the angle and perform four smear samplings from right to left;

[0065] Place the sampling head on the framed building wall surface at an angle of 45° to the sampling surface, and perform the fifth round of smear sampling in a zigzag trajectory from bottom to top. During this period, the sampling head needs to be rotated in time;

[0066] Place the sampling head on the framed building wall surface at an angle of 45° to the sampling surface, and perform the sixth smear sampling in a zigzag trajectory from top to bottom. During this period, the sampling head needs to be rotated in time;

[0067] Place the sampling head on the framed building wall surface at an angle of 45° to the sampling surface, and perform the seventh round of smear sampling from left to right in a zigzag trajectory. During this period, the sampling head needs to be rotated in time;

[0068] Place the sampling head on the framed building wall at an angle of 45° to the sampling surface, and perform the eighth smear sampling back and forth from right to left in a zigzag trajectory. During this period, the sampling head needs to be rotated in time.

[0069] In the above collection process, the rectangular sampling specification plate used has a thickness of 1 mm; the inner and outer frame contours of the rectangular sampling specification plate are square, the inner frame side length is 200 mm; the outer frame side length is 400 mm; of course, the specific size can be determined according to the actual application.

[0070] The building wall area framed by the inner frame is the sampling area; when used, the rectangular sampling specification plate is tightly fitted on the building wall to be tested to prevent gaps around the inner frame from causing leakage.

[0071] Rectangular sampling specification plates can be made of acrylic sheets.

[0072] Step F: Label and store

[0073] After completing step E, place the broken sampling head in the sampling tube; label the collected samples on the frosted part of the sampling tube wall and on the sampling tube storage box; when storing the sampling tubes, leave one empty space in each row of the sampling tube storage box and place the samples in order.

[0074] The following table is: Descriptive statistics of standard deviation used in actual experiments

[0075] Descriptive statistics table of standard deviation

[0076]

[0077] Using the collection method of the present invention, more than 20 buildings with mosaic and tile surface materials were selected in a coastal area, and 255 samples were collected from the wall surfaces in four directions, a total of 85 groups, and 3 parallel samples in each group. The average value of all data is 34.68 mg / ㎡, the minimum value of the standard deviation is 0.19, and the maximum value is 8.84. The average value of the standard deviation (SD) of each group is 2.69, the confidence interval of the 95% confidence level is [2.30, 3.08], and the standard error (SE) is 0.19. It shows that the sampling method is reliable and effective.

[0078] As described above, the present invention can be well implemented. The sampling method of the present invention has the characteristics of convenient operation, high sampling efficiency and low cost, and can realize non-destructive and accurate sampling of chloride salt deposited on the surface of dense wall of a building.

[0079] The implementation methods of the present invention are not limited to the above-mentioned embodiments, and any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention.

Claims

1. A method for collecting chloride salt deposited on the surface of a dense wall of a building, characterized in that The steps include: Step A: Filling the sample solution Take pure water and fill it into the sampling tube; Step B: Packing and shipping Place the filled sampling tubes in a sampling tube storage box with multiple grids; When placing the sampling tubes, do not place the sampling tubes in the first cell of the odd-numbered rows of the sampling tube storage box, and do not place the sampling tubes in the last cell of the even-numbered rows to avoid squeezing the sampling tubes. Then transport them to the experimental site. Step C: Locate sampling points At the experimental site, the building wall to be tested is located at a height of 1.2m-1.5m above the ground as the building wall sampling area; Step D: Wetting the sampling head At the experimental site, the flocked sampling swab was inserted into the sampling liquid in the sampling tube in step A to be immersed, and then slowly taken out to above the liquid level of the sampling liquid, and reciprocatedly hit the wall of the sampling tube four times to shake off the excess liquid, and finally slid out along the wall of the sampling tube to reduce the sampling liquid attached to the flocked sampling swab again, so that the flocked sampling swab was moist but not dripping; Step E: Smear sampling At the experimental site, a rectangular sampling specification plate is placed on the sampling area of ​​the building wall to be tested in step C, the four sides of the rectangular sampling specification plate are fixed and tightly attached to the sampling area of ​​the building wall to be tested, and the flocked sampling swab that is moistened but not dripping in step D is used to smear and sample eight times in the sampling area of ​​the building wall framed by the rectangular sampling specification plate; Step F: Label and store After completing the sampling in step E, place the broken sampling head in the sampling tube; label the collected samples on the frosted part of the sampling tube wall and the sampling tube storage box; when storing the sampling tubes, leave one empty space in each row of the sampling tube storage box and place the samples in order; In step A, pure water is taken and poured into the sampling tube. Specifically, 10-15 ml of pure water with a resistivity of 18.2 MΩ•cm is taken at 22-25° C. and poured into the sampling tube; In the step D of infiltrating the sampling head, the flocked sampling swab used is an oral swab, the total length of the rod is 154 mm, the diameter of the rod is 2.38 mm, the flocked head is 20 mm long, the sampling head diameter is 5.36 mm, and the break point is located 30.78 mm away from the end of the sampling head; In the smear sampling process of step E, a wet flocked sampling swab is used to smear and sample the building wall defined by the inner frame eight times on the inner frame of the rectangular sampling specification plate, specifically: Place the sampling head parallel to the framed building wall surface to be sampled, and perform a smear sampling from bottom to top; Place the sampling head parallel to the framed building wall surface to be sampled, rotate the angle and perform secondary smear sampling from top to bottom; Place the sampling head parallel to the framed building wall surface to be sampled, turn the angle and smear the sample three times from left to right; Place the sampling head parallel to the framed building wall surface to be sampled, turn the angle and perform four smear samplings from right to left; Place the sampling head on the framed building wall surface at an angle of 45° to the sampling surface, and perform the fifth round of smear sampling in a zigzag trajectory from bottom to top. During this period, the sampling head needs to be rotated in time; Place the sampling head on the framed building wall surface at an angle of 45° to the sampling surface, and perform the sixth smear sampling in a zigzag trajectory from top to bottom. During this period, the sampling head needs to be rotated in time; Place the sampling head on the framed building wall surface at an angle of 45° to the sampling surface, and perform the seventh round of smear sampling from left to right in a zigzag trajectory. During this period, the sampling head needs to be rotated in time; Place the sampling head on the framed building wall at an angle of 45° to the sampling surface, and perform the eighth smear sampling back and forth from right to left in a zigzag trajectory. During this period, the sampling head needs to be rotated appropriately.

2. The method for collecting chloride salt deposited on the surface of a dense wall of a building according to claim 1, characterized in that: During the filling of the sampling liquid in step A, a manual single-channel adjustable pipette is used to take 10 ml of pure water. The specific operation is to place the sampling tube in a four-decimal electronic balance and return it to zero, use a pipette to take pure water and inject it into the sampling tube, observe the balance reading, and use a dropper to add pure water drop by drop until the two decimal places meet the requirements.

3. The method for collecting chloride salt deposited on the surface of a dense building wall according to claim 1, characterized in that: In step E, the thickness of the rectangular sampling specification plate is 1 mm; The inner frame of the rectangular sampling specification plate is a square with a side length of 200 mm; The building wall area framed by the inner frame is the sampling area; when sampling, the rectangular sampling specification plate is tightly attached to the building wall to be tested to prevent gaps around the inner frame from causing leakage.

4. The method for collecting chloride salt deposited on the surface of a dense building wall according to claim 3, characterized in that: The rectangular sampling specification plate is an acrylic plate.

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