Device and method for detecting chlorine ion content of fresh concrete

Abstract

The invention discloses a device and method for detecting the chlorine ion content of fresh concrete, and belongs to the technical field of concrete quality control. The device for detecting the chlorine ion content of the fresh concrete comprises a shell, and the shell is provided with a containing cavity; the reference electrode and the shell are coaxially arranged, and the reference electrode extends in the axial direction of the containing groove; the chloride ion electrodes are arranged on the peripheral side of the reference electrode in the circumferential direction; the plurality of temperature electrodes are arranged on the peripheral side of the reference electrode in the circumferential direction; the plurality of pH electrodes are arranged on the peripheral side of the reference electrode in the circumferential direction; and the coating structure is used for blocking the external environment and the electrode. A multi-electrode system integrating the probe and the acquisition terminal can be formed by combining the chloride ion electrode, the temperature electrode, the pH electrode and other electrodes, comprehensive detection of multiple parameters such as the chloride ion content, the temperature and the pH value in concrete is achieved, the service life of the electrodes is prolonged, and the reliability of a data source is improved.

Description

Technical Field

[0001] The invention relates to the technical field of concrete quality control, in particular to a detection device and method for chloride ion content in fresh concrete. Background Art

[0002] Due to the vigorous development of infrastructure construction, the amount of concrete used has increased dramatically, river sand resources are in short supply, and the price remains high. At the same time, excessive exploitation of river sand has destroyed the riverbed, caused serious soil erosion, and affected the river's ecological environment. For this reason, using seawater sand as raw material can reduce the dependence of construction engineering structures on river sand, but because the chloride ion content in seawater sand exceeds the standard, it usually needs to go through multiple processes to reduce its chloride ion content to meet the actual engineering needs. Therefore, in order to ensure that the chloride ions in the concrete structure meet the use requirements and ensure the safe use of reinforced concrete structures, it is necessary to effectively detect the chloride ion concentration in the freshly mixed concrete during the construction process to ensure the durability of the concrete structure.

[0003] In the prior art, electrochemical testing methods are usually used to determine the chloride ion concentration in fresh concrete. However, due to the heterogeneity of the concrete structure, a single electrode or sensor cannot accurately reflect the actual situation inside the concrete, resulting in data errors. In addition, the AgCl coating on the surface of the existing chloride ion electrode is easily detached in an alkaline environment for a long time, affecting the electrode performance. Summary of the invention

[0004] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a detection device and method for the chloride ion content of fresh concrete, which can reduce the data error caused by the heterogeneity of the concrete structure and improve the reliability of the detection data source.

[0005] According to some embodiments of the present invention, a detection device for chloride ion content in fresh concrete includes: a shell having a containing cavity; a reference electrode, the reference electrode is arranged in the containing cavity, the reference electrode is located at one end of the containing cavity, the reference electrode is coaxially arranged with the containing cavity, and the reference electrode extends along the axial direction of the containing cavity; a plurality of chloride ion electrodes, the plurality of chloride ion electrodes are arranged in the containing cavity, and the plurality of chloride ion electrodes are arranged circumferentially on the circumference of the reference electrode; a plurality of temperature electrodes, the plurality of temperature electrodes are arranged in the containing cavity, and the plurality of temperature electrodes are arranged circumferentially on the circumference of the reference electrode; a plurality of pH electrodes, the plurality of pH electrodes are arranged in the containing cavity, and the plurality of pH electrodes are arranged circumferentially on the circumference of the reference electrode; a coating structure, the coating structure is arranged at one end of the shell close to the reference electrode, the coating structure is covered on the chloride ion electrode, the temperature electrode and the pH electrode, and the coating structure is used to block the external environment from the chloride ion electrode, the temperature electrode and the pH electrode.

[0006] The detection device for the chloride ion content of fresh concrete according to the embodiment of the present invention has at least the following beneficial effects: the reference electrode is coaxially arranged with the accommodating cavity, and the chloride ion electrode, the temperature electrode and the pH electrode are all arranged circumferentially on the circumferential side of the reference electrode, and a multi-electrode system of an integrated probe and an acquisition terminal is formed by combining the arrangement of multiple electrodes such as the chloride ion electrode, the temperature electrode and the pH electrode, thereby realizing comprehensive detection of multiple parameters such as the chloride ion content, temperature and pH value in concrete, and preventing the surface coating of the chloride ion electrode from falling off in an alkaline environment for a long time, so as to provide more comprehensive concrete performance evaluation information, improve the reliability of the data source, and further effectively control the outgoing state of the fresh concrete.

[0007] According to some embodiments of the present invention, a sealant is provided between the groove wall of the accommodating cavity and the reference electrode, the chloride ion electrode, the temperature electrode, the pH electrode and the coating structure, and the sealant is used to prevent fresh concrete from invading the accommodating cavity.

[0008] According to some embodiments of the present invention, the surfaces of the pH electrode and the chloride ion electrode are coated with a protective film, and the protective film is used to prevent the pH electrode and the chloride ion electrode from reacting with the external environment.

[0009] According to some embodiments of the present invention, the protective film is an epoxy resin coating with ethyl acetate as solvent and bicarbonate as filler.

[0010] According to some embodiments of the present invention, a method for detecting chloride ion content in fresh concrete comprises:

[0011] S1: inserting a detection device for chloride ion content of fresh concrete into fresh concrete until a preset detection time is reached;

[0012] S2: obtaining the temperature value detected by each temperature electrode, calculating the temperature average value according to each temperature value, obtaining the first potential detected by each pH electrode, calculating the first potential average value according to each first potential, obtaining the second potential detected by each chloride ion electrode, and calculating the second potential average value according to each second potential;

[0013] S3: calculating a temperature average value according to the temperature, and obtaining a first correction value of the first potential and a second correction value of the second potential;

[0014] S4: Calculate the pH value according to the first potential average value and the first correction value, and calculate the chloride ion concentration value according to the second potential average value and the second correction value;

[0015] S5: Obtain the bulk density, water consumption, pH value and chloride ion concentration of the concrete, and calculate the chloride ion content in the fresh concrete according to the bulk density, water consumption, pH value and chloride ion concentration of the fresh concrete.

[0016] According to some embodiments of the present invention, in S3, the calculation formula of the first correction value is:

[0017] △E pH =0.0016(T-25);

[0018] In the formula, △E pH is the first correction value, and T is the average temperature.

[0019] According to some embodiments of the present invention, in S3, the calculation formula of the second correction value is:

[0020] △E Cl =0.0021(T-25);

[0021] In the formula, △E cl is the second correction value, and T is the average temperature.

[0022] According to some embodiments of the present invention, in S4, the calculation formula of pH value is:

[0023] E pH +△E pH =-42.12pH+263.90;

[0024] In the formula, E pH is the first potential average value, △E pH is the first correction value, and pH is the pH value.

[0025] According to some embodiments of the present invention, in S4, the calculation formula of the chloride ion concentration value is:

[0026] E cl +△E Cl =-47.76lg[c(Cl - )]-5.43;

[0027] In the formula, E cl is the second potential average value, △E Cl is the second correction value, c(Cl - ) is the chloride ion concentration value.

[0028] According to some embodiments of the present invention, in S5, the calculation formula for the chloride ion content in the fresh concrete is:

[0029]

[0030] In the formula, is the chloride ion content in fresh concrete, m 水 is the water consumption, c(Cl - ) is the chloride ion concentration, m 总 is the bulk density of concrete.

[0031] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention is further described below in conjunction with the accompanying drawings and embodiments:

[0033] Figure 1 is a schematic structural diagram of a device for detecting chloride ion content in fresh concrete according to a first aspect of an embodiment of the present invention;

[0034] Figure 2 Figure 1 sectional view of;

[0035] Figure 3 is a schematic flow chart of a method for detecting chloride ion content in fresh concrete according to a second aspect of an embodiment of the present invention;

[0036] Figure 4 This is a graph showing the relationship between the number of frictions of the chloride ion electrode and the data results.

[0037] Reference numerals:

[0038] Housing 100, accommodating cavity 110, sealant 120;

[0039] Reference electrode 200;

[0040] Chloride ion electrode 300;

[0041] Temperature electrode 400;

[0042] pH electrode 500;

[0043] The structure 600 is coated. DETAILED DESCRIPTION

[0044] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0045] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0046] In the description of the present invention, the meaning of "a plurality" is one or more, the meaning of "a plurality" is more than two, "greater than", "less than", "exceed", etc. are understood as not including the number itself, and "above", "below", "within", etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0047] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0048] refer to Figure 1 to Figure 2 A device for detecting chloride ion content in fresh concrete according to some embodiments of the present invention is described.

[0049] like Figure 1 and Figure 2 As shown, according to some embodiments of the present invention, the detection device for the chloride ion content of fresh concrete includes: a housing 100, the housing 100 has a housing 110; a reference electrode 200, the reference electrode 200 is arranged in the housing 110, the reference electrode 200 is located at one end of the housing 110, the reference electrode 200 is coaxially arranged with the housing 110, and the reference electrode 200 extends along the axial direction of the housing 110; a plurality of chloride ion electrodes 300, the plurality of chloride ion electrodes 300 are arranged in the housing 110, and the plurality of chloride ion electrodes 300 are arranged around the reference electrode 200 in a circumferential direction; a plurality of temperature electrodes 400, the plurality of temperature electrodes 400 are arranged in the housing 110, and the plurality of chloride ion electrodes 300 are arranged in a circumferential direction on the circumference of the reference electrode 200; a plurality of temperature electrodes 400, the plurality of temperature electrodes 400 are arranged in the housing 110, and the plurality of chloride ion electrodes 300 are arranged in the housing 110. 400 is arranged in the accommodating cavity 110, and multiple temperature electrodes 400 are arranged on the circumferential side of the reference electrode 200 in a circumferential direction; multiple pH electrodes 500, multiple pH electrodes 500 are arranged in the accommodating cavity 110, and multiple pH electrodes 500 are arranged on the circumferential side of the reference electrode 200 in a circumferential direction; a coating structure 600, the coating structure 600 is arranged at one end of the housing 100 close to the reference electrode 200, the coating structure 600 is covered on the chloride ion electrode 300, the temperature electrode 400 and the pH electrode 500, and the coating structure 600 is used to block the external environment from the chloride ion electrode 300, the temperature electrode 400 and the pH electrode 500.

[0050] like Figure 1As shown, the housing 100 is a tubular structure and has a columnar accommodating chamber 110. The reference electrode 200, the chloride ion electrode 300, the temperature electrode 400 and the pH electrode 500 are arranged at the lower end of the accommodating chamber 110. The reference electrode 200, the chloride ion electrode 300, the temperature electrode 400 and the pH electrode 500 extend along the axial direction of the accommodating chamber 110. The coating structure 600 is covered on the chloride ion electrode 300, the temperature electrode 400 and the pH electrode 500, that is, the reference electrode 200 is penetrated in the coating structure 600. Figure 2 As shown, the reference electrode 200 is coaxially arranged with the accommodating cavity 110 , and the chloride ion electrode 300 , the temperature electrode 400 and the pH electrode 500 are all arranged on the circumferential side of the reference electrode 200 in a circumferential direction.

[0051] It should be noted that the heterogeneity of concrete refers to the spatial inhomogeneity or uneven distribution of the properties, components or structures inside the concrete material. Concrete is a complex multiphase material, which contains multiple components such as cement matrix, aggregate, pores, additives, etc. These components will cause the internal structure to be uneven during the curing and molding process of concrete. The heterogeneity of concrete is mainly manifested in uneven distribution of components, uneven pore structure, and microstructural heterogeneity. Specifically, the cement matrix, aggregate, additives and other components in concrete may settle, stratify or mix unevenly during pouring and curing, resulting in uneven distribution of components inside the concrete; factors such as the size, shape, and distribution of concrete pores may lead to the inhomogeneity of the pore structure inside the concrete; the microstructure of concrete has different components such as particle gaps, cement colloids, and crystals, and the spatial distribution of these components may be uneven. Therefore, due to the heterogeneity inside the concrete, the concrete performance in different regions may be different. When testing, if the sampling is not representative enough or the test area is not properly selected, it is easy to increase the dispersion of the test data, so that the average value or statistical inference of the data is affected.

[0052] Therefore, by combining the settings of multiple electrodes such as the chloride ion electrode 300, the temperature electrode 400 and the pH electrode 500 to form a multi-electrode system of integrated probes and acquisition terminals, comprehensive detection of multiple parameters such as chloride ion content, temperature and pH value in concrete can be achieved to provide more comprehensive concrete performance evaluation information, avoid data errors caused by the heterogeneity of the concrete structure, improve the reliability of the data source, and effectively control the outgoing state of the freshly mixed concrete.

[0053] In this specific embodiment, two temperature electrodes 400 and two pH electrodes 500 are respectively provided, and the two temperature electrodes 400 are respectively provided on opposite sides of the reference electrode 200, and the pH electrodes 500 are respectively provided on opposite sides of the reference electrode 200. Four chloride ion electrodes 300 are provided, and the chloride ion electrodes 300 are divided into two groups with two chloride ion electrodes 300 as a group, and the two groups of chloride ion electrodes 300 are respectively provided on opposite sides of the reference electrode 200, then the chloride ion electrodes 300, the temperature electrodes 400 and the pH electrodes 500 are all provided around the reference electrode 200 in a circumferential direction.

[0054] Furthermore, a display screen is also provided on the housing 100. It should be noted that a test terminal and an acquisition circuit board are provided in the accommodating cavity 110, which accurately and real-time calculate the chloride ion content of the fresh concrete by recording data from the fresh concrete test and combining the chloride ion and potential relationship model given by indoor experiments, and finally display the result of the chloride ion content in the fresh concrete through the display screen.

[0055] For the pH electrode 500 described in the present invention, its substrate is a cylindrical titanium sheet prepared by thermal decomposition. In the preparation process, first prepare a 0.5 to 1 mol / L ammonium hexachloroiridate aqueous solution as a precursor solution, then add a small amount of ethylene glycol as a dispersant to the precursor solution, spray the solution on the surface of the titanium sheet, and then place it in an oven at 90 to 110°C for more than 30 minutes, and repeat this spraying and baking steps 3 to 5 times. After baking, the sample is placed in a muffle furnace for high-temperature treatment, wherein the heating temperature is controlled between 700 and 800°C and the heating time is 4 to 6 hours. Finally, the heated pH electrode 500 is placed in a saturated calcium hydroxide solution for activation for 28 days for use, so that the surface film layer reacts fully with the solution and becomes denser.

[0056] It should be noted that the use of ammonium hexachloroiridate aqueous solution as a precursor solution, combined with ethylene glycol as a dispersant, is conducive to the formation of uniform and high-quality electrode materials on the surface of the titanium sheet, and improves the reaction performance of the pH electrode 500. At the same time, through multiple spraying and baking steps, the uniform distribution and full solidification of the electrode material can be ensured, thereby improving the preparation efficiency and reducing the error in the preparation process, and then high-temperature treatment is performed in a muffle furnace to further stabilize the electrode structure, so that it has better long-term stability and ensures stable operation under different environmental conditions.

[0057] The reference electrode 200 in this specific embodiment is a solid MnO 2 reference electrode 200 .

[0058] The reference electrode 200 in this specific embodiment is the temperature electrode 400 which is the thermistor electrode PT100.

[0059] The chloride ion electrode 300 described in the present invention has a cylindrical silver sheet as its substrate prepared by constant current electroplating. During the preparation process, the current is 0.2 to 1 mA / cm 2 The application time is 0.5 to 3 hours, the electroplating solution is 0.05 to 0.2 mol / L HCl solution, and finally the electroplated chloride ion electrode 300 needs to be placed in a 0.1 mol / L KCL solution for activation for 7 days for use, so that the surface film layer can fully react with the solution and become denser.

[0060] In some specific embodiments of the present invention, the surfaces of the pH electrode 500 and the chloride ion electrode 300 are coated with a protective film, which can isolate the probe from the outside world and protect the chloride ion electrode 300 and the pH electrode 500. It should be noted that in a highly alkaline environment, the stability of the Ag / AgCl electrode is poor, and the AgCl film layer on its surface is easily exposed to OH. - Therefore, in order to ensure the accuracy and stability of the chloride ion electrode 300 detection, necessary measures need to be taken to ensure that it has a good chloride ion monitoring function in a high alkaline environment.

[0061] In this specific embodiment, the protective film is an epoxy resin or polyurethane coating, wherein bicarbonate or carbonate is added as a filler in the coating, and ethyl acetate, acetone, etc. are used as the coating solvent. It should be noted that the solvent dilutes the coating concentration, which can increase the porosity of the coating and appropriately soften the coating, and the carbonate filler is for the purpose of subsequent immersion in an acidic solution to react with it, thereby increasing the porosity of the coating surface, thereby ensuring that the contact channel between the probe and the solution is unobstructed.

[0062] Specifically, the filler particle size is between 50 and 500 nm, the filler ratio is 5 to 20 wt%, and the resin to solvent ratio is 1:0.5 to 1. The film layer is coated by brushing or spraying, and the film thickness is between 50 and 100 μm. After the coating is completed, the chloride ion electrode 300 and the pH electrode 500 are placed at room temperature for curing for 48 hours. Finally, the prepared chloride ion electrode 300 and pH electrode 500 are immersed in 0.1 to 1 mol H2SO4 or HNO3 solution for 7 days.

[0063] In some specific embodiments of the present invention, a sealant 120 is provided between the groove wall of the accommodating cavity 110 and the reference electrode 200, the chloride ion electrode 300, the temperature electrode 400, the pH electrode 500 and the coating structure 600, and the sealant 120 is used to prevent the fresh concrete from invading the accommodating cavity 110. Figure 1As shown, the sealant 120 is wrapped around the outer walls of the reference electrode 200, the chloride ion electrode 300, the temperature electrode 400 and the pH electrode 500, and the sealant 120 is interconnected with the coating structure 600, so the sealant 120 further plays a role in limiting the distribution positions of the reference electrode 200, the chloride ion electrode 300, the temperature electrode 400 and the pH electrode 500 in the accommodating cavity 110.

[0064] refer to Figure 3 to Figure 4 The following describes a method for detecting chloride ion content in fresh concrete according to an embodiment of the second aspect of the present invention. The device for detecting chloride ion content in fresh concrete according to an embodiment of the second aspect of the present invention comprises:

[0065] S1: inserting a detection device for chloride ion content of fresh concrete into fresh concrete until a preset detection time is reached;

[0066] S2: obtaining the temperature value detected by each temperature electrode 400, calculating the temperature average value according to each temperature value, obtaining the first potential detected by each pH electrode 500, calculating the first potential average value according to each first potential, obtaining the second potential detected by each chloride ion electrode 300, and calculating the second potential average value according to each second potential;

[0067] S3: calculating a temperature average value according to the temperature, and obtaining a first correction value of the first potential and a second correction value of the second potential;

[0068] S4: Calculate the pH value according to the first potential average value and the first correction value, and calculate the chloride ion concentration value according to the second potential average value and the second correction value;

[0069] S5: Obtain the bulk density, water consumption, pH value and chloride ion concentration of the concrete, and calculate the chloride ion content in the fresh concrete according to the bulk density, water consumption, pH value and chloride ion concentration of the fresh concrete.

[0070] The calculation formulas for the temperature average value, the first potential average value, and the second potential average value in S2 are:

[0071]

[0072] Wherein, T1 and T2 are the temperature values ​​detected by each temperature electrode 400, T is the average temperature, and E pH1 、E pH2 are the first potential detected by each pH electrode 500, E pH is the first potential average value, E Cl1 、E Cl2 、E Cl3 、E Cl4are the second potentials detected by each chloride ion electrode 300, E Cl The second potential average value.

[0073] For the first correction value in S3, the calculation formula is:

[0074] △E pH =0.0016T-25;

[0075] In the formula, △E pH is the first correction value, and T is the average temperature.

[0076] For the second correction value in S3, the calculation formula is:

[0077] △E Cl =0.0021T-25;

[0078] In the formula, △E Cl is the second correction value, and T is the average temperature.

[0079] The calculation formula for the pH value in S4 is:

[0080] E pH +△E pH =-42.12pH+263.90;

[0081] In the formula, E pH is the first potential average value, △E pH is the first correction value, and pH is the pH value.

[0082] The calculation formula for the chloride ion concentration in S4 is:

[0083] E cl +△E Cl =-47.76lg[c(Cl - )]-5.43;

[0084] In the formula, E cl is the second potential average value, △E Cl is the second correction value, c(Cl - ) is the chloride ion concentration value. The calculation formula for the chloride ion content in the fresh concrete in S5 is:

[0085]

[0086] In the formula, is the chloride ion content in fresh concrete, m 水 is the water consumption, c(Cl - ) is the chloride ion concentration, m 总 is the bulk density of concrete.

[0087] The following is a specific example to illustrate the method for making a device for detecting chloride ion content in fresh concrete.

[0088] By processing, circular φ10mm metallic silver and φ10mm metallic titanium were obtained, and the surface oil was cleaned by ultrasonic cleaning with anhydrous ethanol, and the surface was polished with 600-mesh sandpaper, and then polished flat on 1200-mesh sandpaper. Ultrasonic treatment was performed in anhydrous ethanol for 30 minutes to obtain circular φ10mm metallic silver and φ10mm metallic titanium electrode substrates.

[0089] A circular titanium sheet was used as a substrate, and a 1 mol / L ethanol solution of ammonium hexachloroiridate was used as a mother liquid. The mother liquid was evenly sprayed onto the surface of the titanium sheet using a spray gun, and then baked in an oven at 105°C for 2 hours. The spraying and baking steps were performed three times, and then a high-temperature reaction was carried out at 750°C in a muffle furnace for 5 hours to obtain a pH electrode 500 with an IrOx film on the surface.

[0090] One side of the circular silver sheet was retained and the other side of the circular silver sheet was sealed with epoxy resin. In a 0.1 mol / L HCl solution, the circular silver sheet was used as an anode and the titanium mesh was used as a cathode. A current of 1 mA was applied by a constant potential instrument for 1 hour to obtain a chloride ion electrode 300.

[0091] The pH electrode 500 was placed in a saturated calcium hydroxide solution for activation for 28 days and the chloride ion electrode 300 was placed in a 0.1 mol / L KCl solution for activation for 7 days.

[0092] Grind 0.8 g of NaHCO3 thoroughly, then add it to 10 g of epoxy resin and stir thoroughly. Weigh 3.3 g of curing agent and 8 g of acetone, add them to the mixture of NaHCO3 and epoxy resin and stir thoroughly. Then, apply the epoxy resin evenly on the surface of the pH electrode 500 and the chloride ion electrode 300 by spraying, and place them horizontally to allow them to stand at room temperature for 48 hours before curing.

[0093] After the surface coatings of the pH electrode 500 and the chloride ion electrode 300 are cured, the pH electrode 500 and the chloride ion electrode 300 are immersed in a 0.1 mol / L nitric acid solution for 7 days to complete the treatment of the protective film.

[0094] At room temperature of 25°C, the chloride ion electrode 300 was immersed in 0.1mol / L, 0.5mol / L, 1mol / L, 1.5mol / L, 2mol / L, and 3mol / L sodium chloride solutions, respectively, to obtain the relationship curve between potential and chloride ion concentration, as shown in Table 1. Similarly, the pH electrode 500 was immersed in buffer solutions of pH 7, pH 10, pH 11, pH 13, and pH 14, respectively, to obtain the relationship curve between pH potential and physical quantity, as shown in Table 2.

[0095] Table 1 Chloride ion probe test results

[0096] Serial number Solution chloride ion concentration mol / L Test potential result mV 1 0.1 40.0 2 0.5 12.1 3 1 -2.0 4 1.5 -14.9 5 2 -21.2 6 3 -30.1

[0097] Table 2 pH probe test results

[0098] Serial number Solution pH Test potential result mV 1 7 -32.0 2 10 -158.4 3 11 -201.0 4 13 -285.5 5 14 -326.9

[0099] According to the relationship curves in Table 1 and Table 2, the fitting relationship between the potential of pH, chloride ion electrode 300 and the physical quantity is obtained, the reference electrode 200, the chloride ion electrode 300, the temperature electrode 400 and the pH electrode 500 are installed and fixed in sequence according to the designed positions, the wires are led out, and epoxy resin is poured to seal, the circuit board is placed in the accommodating cavity 110 for assembly, and the above relationship curves are recorded in the chip through programming, so as to obtain a detection device for the chloride ion content of fresh concrete.

[0100] The following is a specific example to illustrate the detection method of chloride ion content in fresh concrete.

[0101] The mix ratio of concrete used in a certain project is shown in Table 3 below:

[0102] Table 3 Concrete material mix ratio of a certain wharf (kg)

[0103] cement sand stone water Admixtures Admixture 362 765 1056 145 5.44 91

[0104] Insert the detection device of chloride ion content of fresh concrete into the fresh concrete for 30s.

[0105] The temperature values ​​detected by the temperature electrode 400 are obtained: T1 = 30.5°C, T2 = 30.9°C, and the average temperature value is calculated based on T1 and T2:

[0106]

[0107] Obtain the first potential detected by the pH electrode 500: E pH1 =-294.10MV, E pH2 =-295.30MV, according to E pH1 and E pH2 Calculate the first potential average value:

[0108]

[0109] Obtain the second potential detected by the chloride ion electrode 300: E Cl1 =110.00mV, E Cl2 =106.10mV, E Cl3 =113.50mV, E Cl4 =108.90mV, according to ECl1 、E Cl2 、E Cl3 、E Cl4 Calculate the first potential average value:

[0110]

[0111] Calculate the temperature average value according to the temperature and obtain the first correction value of the first potential:

[0112] △E pH =0.0016(T-25)=0.00912mV;

[0113] Calculate the temperature average value according to the temperature and obtain the second correction value of the second potential:

[0114] △E Cl =0.0021(T-25)=0.01197mV;

[0115] E pH and ∆E pH Substitute into the pH value calculation formula:

[0116] -294.70+0.00912=-42.12pH+263.90;

[0117] Obtained: pH = 13.3.

[0118] E cl and ∆E Cl Substitute into the pH value calculation formula:

[0119] 109.63+0.01197=-47.76lg[c(Cl - )]-5.43;

[0120] Obtain: c(Cl - )=-0.0039mol / L.

[0121] M 水 、c(Cl - ) and m 总 Substitute into the pH value calculation formula:

[0122]

[0123] The chloride ion content in the fresh concrete is finally obtained.

[0124] It should be noted that a protective film is obtained by brushing on the chloride ion electrode 300 and the pH electrode 500, which can enhance the wear resistance and alkali resistance of the electrodes while ensuring the pH and chloride ion sensing functions of the electrodes. The wear resistance of the detection device for the chloride ion content of fresh concrete is described below with a specific embodiment.

[0125] A 100 g weight was placed on the chloride ion electrode 300, and a cycle was made by dragging the weight on the 800-grit sandpaper for 30 cm. The potential change of the chloride ion electrode 300 in the 0.1 mol / L NaCl solution was measured in 50 cycles. Figure 4 As shown, the two broken lines represent the chloride ion electrode 300 with a protective film and the chloride ion electrode 300 without a protective film, respectively, wherein the broken line located at the top is the chloride ion electrode 300 with a protective film, from which it can be seen that the potential change of the chloride ion electrode 300 with a protective film within 50 cycles is relatively gentle and remains at a high level, while the potential change of the chloride ion electrode 300 without a protective film is more drastic, and the overall potential value is lower. This shows that the chloride ion electrode 300 with a protective film has better stability and anti-interference ability, and can enhance the wear resistance and alkali resistance of the electrode while ensuring the electrode's sensing function for pH and chloride ions. Compared with the electrode without a protective film, it is more reliable and durable in practical applications.

[0126] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present invention.

Claims

1. A detection device for chloride ion content of fresh concrete, characterized in that: include: A housing (100), wherein the housing (100) has a receiving cavity (110); A reference electrode (200), the reference electrode (200) being arranged in the accommodating cavity (110), the reference electrode (200) being located at one end of the reference electrode (200), the reference electrode (200) being arranged coaxially with the reference electrode (200), and the reference electrode (200) extending along the axial direction of the accommodating cavity (110); A plurality of chloride ion electrodes (300), wherein the plurality of chloride ion electrodes (300) are arranged in the accommodating cavity (110), and the plurality of chloride ion electrodes (300) are arranged in a circumferential direction on the circumference of the reference electrode (200); A plurality of temperature electrodes (400), wherein the plurality of temperature electrodes (400) are arranged in the accommodating cavity (110), and the plurality of temperature electrodes (400) are arranged in a circumferential direction on the circumference of the reference electrode (200); a plurality of pH electrodes (500), wherein the plurality of pH electrodes (500) are arranged in the accommodating cavity (110), and the plurality of pH electrodes (500) are arranged in a circumferential direction on the circumference of the reference electrode (200); A coating structure (600) is provided at one end of the housing (100) close to the reference electrode (200), and the coating structure (600) is provided to cover the chloride ion electrode (300), the temperature electrode (400) and the pH electrode (500). The coating structure (600) is used to block the external environment from the chloride ion electrode (300), the temperature electrode (400) and the pH electrode (500).

2. The detection device for chloride ion content of fresh concrete according to claim 1, characterized in that: A sealant (120) is provided between the groove wall of the accommodating cavity (110) and the reference electrode (200), the chloride ion electrode (300), the temperature electrode (400), the pH electrode (500) and the coating structure (600), and the sealant (120) is used to prevent fresh concrete from invading the accommodating cavity (110).

3. The detection device for chloride ion content of fresh concrete according to claim 1, characterized in that: The surfaces of the pH electrode (500) and the chloride ion electrode (300) are coated with a protective film, and the protective film is used to prevent the pH electrode (500) and the chloride ion electrode (300) from reacting with the external environment.

4. The detection device for chloride ion content of fresh concrete according to claim 3, characterized in that: The protective film is an epoxy resin coating with ethyl acetate as solvent and bicarbonate as filler.

5. A method for detecting chloride ion content in fresh concrete, using the device for detecting chloride ion content in fresh concrete according to any one of claims 1 to 4, characterized in that: include: S1: inserting a detection device for chloride ion content of fresh concrete into fresh concrete until a preset detection time is reached; S2: obtaining a temperature value detected by each temperature electrode (400), calculating a temperature average value based on each temperature value, obtaining a first potential detected by each pH electrode (500), calculating a first potential average value based on each first potential, obtaining a second potential detected by each chloride ion electrode (300), and calculating a second potential average value based on each second potential; S3: calculating a temperature average value according to the temperature, and obtaining a first correction value of the first potential and a second correction value of the second potential; S4: Calculate the pH value according to the first potential average value and the first correction value, and calculate the chloride ion concentration value according to the second potential average value and the second correction value; S5: Obtain the bulk density, water consumption, pH value and chloride ion concentration of the concrete, and calculate the chloride ion content in the fresh concrete according to the bulk density, water consumption, pH value and chloride ion concentration of the fresh concrete.

6. The method for detecting chloride ion content of fresh concrete according to claim 5, characterized in that: In S3, the calculation formula of the first correction value is: △E pH =0.0016(T-25); In the formula, △E pH is the first correction value, and T is the average temperature.

7. The method for detecting chloride ion content of fresh concrete according to claim 5, characterized in that: In S3, the calculation formula of the second correction value is: △E Cl =0.0021(T-25); In the formula, △E Cl is the second correction value, and T is the average temperature.

8. The method for detecting chloride ion content of fresh concrete according to claim 5, characterized in that: In S4, the pH value is calculated as follows: From pH +△E pH =-42.12pH+263.90; In the formula, E pH is the first potential average value, △E pH is the first correction value, and pH is the pH value.

9. The method for detecting chloride ion content of fresh concrete according to claim 5, characterized in that: In S4, the calculation formula of the chloride ion concentration value is: E cl +△E Cl =-47.76lg[c(Cl - )]-5.43; In the formula, E cl is the second potential average value, △E Cl is the second correction value, c(Cl - ) is the chloride ion concentration value.

10. The method for detecting chloride ion content of fresh concrete according to claim 5, characterized in that: In S5, the calculation formula for the chloride ion content in the fresh concrete is: In the formula, is the chloride ion content in fresh concrete, mwater is the water consumption, c(Cl - ) is the chloride ion concentration, m 总 is the bulk density of concrete.

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