Method for evaluating improvement of concrete surface depth by water permeable template cloth based on fluorescence intensity

Abstract

The application discloses a method for evaluating the improvement of the surface depth of concrete by a water-permeable template cloth based on fluorescence intensity, which comprises the following steps: adding fluorescent powder into the concrete, carrying out color development treatment on the fluorescent powder in the concrete by ultraviolet irradiation, taking a photo, drawing a fluorescence intensity change curve of the concrete, comparing the fluorescence intensity of the concrete sample without the water-permeable template cloth, and calculating the surface depth of the concrete improved by the water-permeable template cloth. Compared with the traditional measurement method, the application has the advantages of convenient testing, high identification precision, quantitative analysis and no damage to the sample, and provides a new method for evaluating the improvement of the surface of the concrete by the water-permeable template cloth.

Description

Technical Field

[0001] This invention belongs to the technical field of concrete surface improvement effect evaluation, specifically involving a method for evaluating the depth of concrete surface improvement by permeable template fabric based on fluorescence intensity. Background Technology

[0002] Most infrastructure projects in my country use concrete structures. Concrete will inevitably deteriorate during long-term service, and this damage generally begins at the surface. If the surface quality of concrete is not improved, it will seriously affect the durability and service life of the concrete. Common methods to improve the surface quality of concrete include changing raw materials and mix proportions, using high-performance release agents, improving construction techniques, and applying permeable formwork fabric. Among these, permeable formwork fabric has the best improvement effect, significantly enhancing the durability of concrete and protecting it from erosion.

[0003] The working principle of permeable formwork is as follows: during the compaction process, excess moisture and air inside the concrete migrate outward and are discharged through the permeable formwork, while cement particles and cementitious materials are retained on the concrete surface. This effectively reduces the local water-cement ratio on the surface, resulting in a dense, hardened layer rich in hydrated calcium silicate, which improves the surface strength and durability. Therefore, the depth of the permeable formwork's influence on the concrete surface is an important indicator for evaluating its effectiveness.

[0004] To accurately identify the structure at different depths within concrete, Chinese invention patent (authorization publication number: CN115201331A) discloses a three-dimensional imaging system and method for the interior of concrete. This patent achieves two-dimensional imaging of concrete at different depths by changing the wavelength of the excitation wave to control the detection depth. Chinese invention patent (authorization publication number: CN106959308A) discloses a method for detecting the depth of impact of fire on concrete structures. This patent utilizes X-ray tomography and Vgstudiomax analysis software to obtain the degree of damage to concrete structures after a fire. Chinese invention patent (authorization publication number: CN 116297177A) discloses a concrete quality testing device for hydraulic engineering. This patent uses multiple pressure sensors moved to corresponding concrete depths for pressure detection. It can be seen that the above-mentioned methods for detecting concrete depth are all relatively complex, and the testing process can damage the concrete sample, making it impossible to quantitatively analyze the depth of concrete surface improved by permeable templates. Summary of the Invention

[0005] To address the aforementioned problem of measuring the depth of surface improvement in concrete using permeable formwork, this invention proposes a method for measuring the surface improvement depth of concrete using permeable formwork based on fluorescence intensity evaluation. This invention offers advantages such as convenient testing, accurate identification results, quantitative analysis, and non-destructive testing of the sample, providing a novel method for testing the surface improvement depth of concrete and overcoming shortcomings in depth detection.

[0006] The technical solution adopted in this invention is as follows:

[0007] A method for evaluating the improvement of concrete surface depth using permeable template fabric based on fluorescence intensity includes the following steps:

[0008] Step 1: Prepare two identical concrete sample molding molds. One mold is left unattached with permeable template fabric as the control group; the other mold has permeable template fabric attached to two sides inside the mold as the experimental group.

[0009] Step 2: Dissolve the water-soluble phosphor in water at a mass ratio of 10%-20% to prepare a fluorescent solution;

[0010] Step 3: Put the fluorescent solution and the remaining concrete materials into a mixer and mix them. Pour the well-mixed concrete slurry into the mold from Step 1 and remove it after curing for 1 day.

[0011] Step 4: Cut the concrete along the center line perpendicular to the permeable formwork, and then put it in an oven to keep the cut surface of the concrete dry.

[0012] Step 5: Irradiate the cut surface of the concrete from Step 4 with an ultraviolet lamp for at least 2 minutes.

[0013] Step 6: Take photos of the concrete cut surface from Step 5 using a high-definition camera.

[0014] Step 7: Convert the photo from Step 6 into a grayscale image. Starting from the concrete surface on one side where the permeable template fabric is pasted, cut a cross-section of a certain width and calculate the average fluorescence intensity in that area. Then drag that area without intervals to the other side of the concrete to obtain the continuous fluorescence intensity of the entire concrete cut surface.

[0015] Step 8: Plot the fluorescence intensity curves of the cut surfaces of the control group and experimental group concrete samples obtained in Step 7, and determine the two intersection points of the fluorescence intensity of the experimental group concrete and the fluorescence intensity of the control group. The distances of these two points from the concrete surface are H1 and H2, respectively. The average of these two values ​​is the surface depth of the concrete improved by the permeable template cloth, and the calculation formula is H=(H1+H2) / 2.

[0016] In step one, the concrete sample molding dimensions are all no less than 100mm in length, width, and height; preferably, the length, width, and height are all controlled within the range of 100mm-150mm, which ensures that the permeable template cloth can function.

[0017] In step two, the particle size range of the water-soluble phosphor is 1-5 μm. This range ensures that the phosphor is easily dispersed in water and that it can be discharged from the template cloth with the water.

[0018] In step two, the water-soluble phosphor is an aluminate phosphor, silicate phosphor, nitride phosphor, or sulfide phosphor, which can develop color under an ultraviolet lamp with a wavelength of 200–400 nm.

[0019] The remaining concrete raw materials in step three include cementitious materials, aggregates, admixtures, etc. This invention is applicable to common concrete in the field. The water in the concrete is replaced with a 10-20% concentration of fluorescent powder solution. The concrete formula is adjusted according to various factors such as project needs, material costs, and the availability of local materials.

[0020] In step four, the oven temperature range is 60℃~100℃, and the drying time is 6~12 hours. More preferably, the oven temperature is 60℃, and the drying time is 12 hours.

[0021] In step five, the light intensity of the ultraviolet lamp is 320~2500 uw / cm². 2 The irradiation time should be controlled between 2 and 5 minutes.

[0022] In step seven, the height of the cross-section should not be less than three times the maximum aggregate size of the concrete, and the width should not exceed 2 mm, to ensure the continuity and accuracy of the fluorescence intensity calculation.

[0023] In step seven, the average fluorescence intensity is the average gray value of the cross section.

[0024] In step eight, the method for determining the intersection point of fluorescence intensity is that if the difference between the two fluorescence intensities is within 5%, then it is considered to be within the range of improvement.

[0025] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0026] This invention discloses a method for evaluating the surface improvement effect of permeable formwork fabric on concrete based on fluorescence intensity. First, fluorescent powder is added to the concrete. The fluorescent powder in the concrete is then developed using ultraviolet irradiation and photographed. A fluorescence intensity change curve inside the concrete is plotted. By comparing the fluorescence intensity with that of a concrete sample without permeable formwork fabric, the surface improvement effect of the permeable formwork fabric on the concrete is calculated. Compared with traditional measurement methods, this invention has the advantages of convenient testing, high identification accuracy, quantitative analysis, and no damage to the sample, providing a new method for evaluating the surface improvement effect of permeable formwork fabric on concrete. Attached Figure Description

[0027] Figure 1 This is a flowchart of the present invention;

[0028] Figure 2 This is a schematic diagram illustrating the method of attaching permeable template fabric.

[0029] Figure 3 Image of the dried cut surface of a concrete sample;

[0030] Figure 4 These are fluorescence images of the control group and the experimental group;

[0031] Figure 5 This is a schematic diagram of fluorescence intensity calculation;

[0032] Figure 6 This is a graph showing the change in fluorescence intensity with distance. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention. Example

[0034] This embodiment provides a method for evaluating the improvement of concrete surface depth using permeable template fabric based on fluorescence intensity. The steps for using this method are described below:

[0035] Step 1: Prepare two identical concrete sample molding molds. One mold is left unattached with permeable template fabric as the control group; the other mold has permeable template fabric attached to both sides inside the mold as the experimental group.

[0036] Step 2: Dissolve the water-soluble phosphor in water at a ratio of 10%-20% to prepare a fluorescent solution.

[0037] Step 3: Put the fluorescent solution and the remaining concrete materials into a mixer and mix them. Pour the well-mixed concrete slurry into the mold from Step 1 and remove it after curing for 1 day.

[0038] Step 4: Cut the concrete along the centerline perpendicular to the permeable formwork, and then place it in a 60°C oven for 12 hours to keep the cut surface of the concrete dry.

[0039] Step 5: Irradiate the cut surface of the concrete from Step 4 with an ultraviolet lamp for at least 2 minutes.

[0040] Step 6: Take photos of the concrete cut surface from Step 5 using a high-definition camera.

[0041] Step 7: Convert the photo from Step 6 into a grayscale image. Starting from the concrete surface on one side where the permeable template fabric is pasted, cut a cross-section of a certain width and calculate the average fluorescence intensity in that area. Then drag that area without intervals to the other side of the concrete to obtain the continuous fluorescence intensity of the entire concrete cut surface.

[0042] Step 8: Plot the fluorescence intensity curves of the cut surfaces of the control group and experimental group concrete samples obtained in Step 7, and determine the two intersection points of the fluorescence intensity of the experimental group concrete and the fluorescence intensity of the control group. The distances of these two points from the concrete surface are H1 and H2, respectively. The average of these two values ​​is the surface depth of the concrete improved by the permeable template cloth, and the calculation formula is H=(H1+H2) / 2.

[0043] The concrete sample molding dimensions in step one should be no less than 100 mm in length, width, and height.

[0044] In step two, the particle size range of the phosphor is 1-5 μm.

[0045] In step seven, the height of the cross-section should not be less than three times the maximum aggregate size of the concrete, and the width should not exceed 2 mm.

[0046] In step eight, the method for determining the intersection point of fluorescence intensity is that if the difference between the two fluorescence intensities is within 5%, then it is considered to be within the range of improvement. Example

[0047] This embodiment evaluates the improvement of concrete surface depth by using the method in Embodiment 1.

[0048] Step 1: Prepare two identical concrete sample molding molds, each 150×150×150mm in size. One mold will not have permeable sheeting attached, serving as the control group. The other mold will have permeable sheeting attached to both sides inside, serving as the experimental group. Figure 2 As shown.

[0049] Step 2: Dissolve water-soluble silicate phosphor (Wang Le Bao brand produced by Haozhipin Decorative Materials) with a particle size of 5μm in water at a mass ratio of 10% to prepare a fluorescent solution.

[0050] Step 3: Put the fluorescent solution and the remaining concrete raw materials into a mixer and mix them. In this embodiment, the remaining concrete raw materials include cementitious materials and aggregates. The cementitious material is P·O42.5 cement, and the aggregate is standard sand with a maximum particle size of 5mm. The ratio of fluorescent solution: cementitious material: aggregate = 22.5:45:135 is added to the mixer and mixed. The mixed concrete slurry is poured into the mold in Step 1 and removed after curing for 1 day.

[0051] Step 4: Cut the concrete along the centerline perpendicular to the permeable formwork, then place it in a 60℃ oven for 12 hours to keep the cut surface of the concrete dry. Figure 3 As shown.

[0052] Step 5: Irradiate the cut surface of the concrete from Step 4 with an ultraviolet lamp at a light intensity of 320 uw / cm². 2 The irradiation time is 3 minutes.

[0053] Step Six: Take photos of the concrete cut surface from Step Five using a high-definition camera (4K-Q13 model). Photos should be taken in a relatively dark environment to prevent other light sources from interfering with the fluorescence effect. Figure 4 As shown.

[0054] Step 7: Convert the photo from Step 6 to a grayscale image. After selecting a suitable threshold (threshold range 85~255), starting from the concrete surface where the permeable template fabric is pasted, cut a cross-section with a height of 150mm and a width of 2mm. Measure the average grayscale value of this area to represent the average fluorescence intensity. Then, drag this area without intervals to the other side of the concrete to obtain the continuous fluorescence intensity of the entire concrete. Figure 5 As shown.

[0055] Step 8: Plot the fluorescence intensity curves of the two concrete samples obtained in Step 7, and determine the two intersection points between the fluorescence intensity of the experimental group and the control group, such as... Figure 6 As shown. By Figure 6 It can be seen that the fluorescence intensity at point A is 101.6 RFU and the fluorescence intensity at point B is 102.6 RFU. The difference between the two is less than 5%. Therefore, points A and B are considered to be intersecting points, and the distance from this position to the surface is H1 = 22 mm. Similarly, the fluorescence intensity at point D is 101.5 RFU and the fluorescence intensity at point C is 103.8 RFU. The difference between the two is less than 5%. Therefore, points C and D are considered to be intersecting points, and the distance from this position to the surface is H2 = 26 mm. By using the formula H = (H1 + H2) / 2, the depth H of the permeable template cloth affecting the concrete surface can be calculated to be 24 mm.

Claims

1. A method for evaluating the depth of permeable template fabric used to improve concrete surface depth based on fluorescence intensity, characterized in that, Includes the following steps: Step 1: Prepare two identical concrete sample molding molds. One mold is left unattached with permeable template fabric as the control group; the other mold has permeable template fabric attached to two sides inside the mold as the experimental group. Step 2: Dissolve the water-soluble phosphor in water at a ratio of 10%-20% to prepare a fluorescent solution; Step 3: Put the fluorescent solution and the remaining concrete materials into a mixer and mix them. Pour the well-mixed concrete slurry into the mold from Step 1, and remove it after curing. Step 4: Cut the concrete along the center line perpendicular to the permeable formwork, and then put it in an oven to keep the cut surface of the concrete dry. Step 5: Irradiate the cut surface of the concrete from Step 4 with an ultraviolet lamp for at least 2 minutes. Step 6: Take photos of the concrete cut surface from Step 5 using a high-definition camera; Step 7: Convert the photo from Step 6 into a grayscale image. Starting from the concrete surface on one side where the permeable template fabric is pasted, cut a cross-section of a certain width and calculate the average fluorescence intensity within the cross-section area. Then drag the cross-section area to the other side of the concrete without intervals to obtain the continuous fluorescence intensity of the entire concrete cut surface. Step 8: Plot the fluorescence intensity curves of the cut surfaces of the control group and experimental group concrete samples obtained in Step 7, and determine the two intersection points of the fluorescence intensity of the experimental group concrete and the fluorescence intensity of the control group. The distances of these two points from the concrete surface are H1 and H2, respectively. The average of these two values ​​is the surface depth of the concrete improved by the permeable template cloth, and the calculation formula is H=(H1+H2) / 2.

2. The method for evaluating the depth of permeable template fabric for improving concrete surface based on fluorescence intensity according to claim 1, characterized in that: The concrete sample molding dimensions in step one should be no less than 100 mm in length, width, and height.

3. The method for evaluating the depth of permeable template fabric for improving concrete surface depth based on fluorescence intensity according to claim 1, characterized in that: In step two, the particle size range of the phosphor is 1-5 μm.

4. The method for evaluating the depth of permeable template fabric for improving concrete surface depth based on fluorescence intensity according to claim 1, characterized in that: In step two, the water-soluble phosphor is an aluminate phosphor, silicate phosphor, nitride phosphor, or sulfide phosphor.

5. The method for evaluating the depth of permeable template fabric for improving concrete surface depth based on fluorescence intensity according to claim 1, characterized in that: In step four, the oven temperature is 60℃~100℃, and the drying time is 6~12 hours.

6. The method for evaluating the depth of permeable template fabric for improving concrete surface depth based on fluorescence intensity according to claim 1, characterized in that: In step five, the light intensity of the ultraviolet lamp is 320~2500 uw / cm². 2 The irradiation time should be controlled between 2 and 5 minutes.

7. The method for evaluating the depth of permeable template fabric for improving concrete surface depth based on fluorescence intensity according to claim 1, characterized in that: In step seven, the height of the cross-section should not be less than three times the maximum aggregate size of the concrete, and the width should not exceed 2 mm.

8. The method for evaluating the depth of permeable template fabric for improving concrete surface depth based on fluorescence intensity according to claim 1, characterized in that: In step eight, the method for determining the intersection point of fluorescence intensity is that if the difference between the two fluorescence intensities is within 5%, then it is considered to be within the range of improvement.

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