Method for testing chloride ion penetration resistance of prefabricated high-strength concrete member node

Abstract

The invention relates to a method for testing the chloride ion penetration resistance of a prefabricated high-strength concrete member node, which comprises the following steps of: bonding two high-strength concrete test blocks with the same size by using a binder to obtain a prefabricated high-strength concrete member, soaking the prefabricated high-strength concrete member in a high-chlorine-content solution for a preset specific age, and then taking out the prefabricated high-strength concrete member; the method comprises the following steps: cutting a prefabricated high-strength concrete member soaked to a preset specific age according to a preset cutting mode to obtain a plurality of prefabricated high-strength concrete member test samples, and measuring the mass concentration of chloride ions in each prefabricated high-strength concrete member test sample by using an ion chromatography, therefore, the chloride ion penetration resistance of the node of the prefabricated high-strength concrete member can be accurately determined.

Description

Technical Field

[0001] The invention relates to the field of prefabricated high-strength concrete component detection, and in particular to a method for testing the chloride ion penetration resistance of a prefabricated high-strength concrete component node. Background Art

[0002] Chloride ion permeability is a key indicator for evaluating the durability and corrosion resistance of concrete. It is particularly important for concrete structures that are exposed to chloride environments for a long time, such as marine environmental engineering, bridge structures, and underground parking lots. The penetration of chloride ions into concrete can cause two destructive effects: on the one hand, chloride ions react chemically with concrete components to cause expansion stress, which in turn causes cracking of the concrete structure and deterioration of mechanical properties; on the other hand, chloride ions penetrate into the surface of steel bars and destroy the passivation film, inducing electrochemical corrosion of steel bars, and ultimately causing durability damage such as cracking and peeling of the concrete protective layer. This dual destructive mechanism significantly reduces the service life and safety performance of concrete structures. For high-strength concrete, although high-strength concrete itself has excellent resistance to chloride ion penetration, due to construction process limitations, the joints of component nodes cannot achieve complete water sealing, resulting in dry joint nodes becoming weak links for chloride ion corrosion.

[0003] Chinese invention patent application CN118758832A discloses a method for testing the chloride ion penetration resistance of concrete. The method first immerses a concrete specimen in a chloride ion solution and leaves it to stand for a set time, then breaks the specimen to obtain two fresh fracture surfaces. A color reaction is performed by spraying a silver nitrate solution on the fracture surface; and image acquisition technology is used to distinguish the colored area and the non-colored area on the fracture surface. The diffusion area ratio and the equivalent diffusion depth are calculated based on image analysis. The test method of the invention has good adaptability, accurate and reliable results, and is suitable for large-size aggregate concrete.

[0004] However, the test method for the chloride ion penetration resistance of concrete disclosed in the above-mentioned invention patent application CN118758832A has shortcomings: although it can test the chloride ion penetration resistance of concrete, its test object is limited to a single concrete specimen, and it fails to fully consider the particularity of the connection nodes of prefabricated components in actual engineering, and has obvious limitations. Generally speaking, there are usually two ways to connect small-sized components (such as high-strength concrete formwork) with limited space: one is to use adhesives to connect different components, and the other is to connect them by secondary pouring. For nodes connected by adhesives, under the long-term action of environmental factors (such as temperature, humidity and wind speed, etc.), microcracks are prone to occur in the interface area, forming a rapid chloride ion penetration channel, which significantly accelerates the erosion process. For the nodes connected by new and old concrete, due to the existence of the interface transition zone, their porosity and chloride ion diffusion coefficient are often higher than 30%~50% of the main concrete, becoming a weak link in durability. This defect makes it difficult for the method in CN118758832A to accurately reflect the corrosion resistance of similar components under actual service conditions, especially the inability to obtain chloride ion corrosion data of the key weak part of the node. This defect will lead to a significant deviation between the durability assessment results based on this method and the actual service life of the components, thus affecting the safety and long-term performance prediction of the engineering structure. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for testing the chloride ion penetration resistance of prefabricated high-strength concrete component nodes in view of the above-mentioned prior art, which can test the chloride ion penetration resistance of the prefabricated high-strength concrete component nodes.

[0006] The technical solution adopted by the present invention to solve the above technical problems is: a method for testing the chloride ion penetration resistance of prefabricated high-strength concrete component nodes, comprising the following steps: Step S1, preparing two high-strength concrete test blocks of the same size, and performing demoulding treatment on each high-strength concrete test block to obtain two high-strength concrete test block samples; Step S2, using an adhesive to bond two high-strength concrete test block samples on their contact surfaces to obtain a prefabricated high-strength concrete component containing the adhesive; wherein the bonding point of the two high-strength concrete test block samples is the component node of the prefabricated high-strength concrete component; Step S3, immersing the prefabricated high-strength concrete component in a solution with a high chloride content until a preset specific age; Step S4, cutting the prefabricated high-strength concrete components that have been soaked to a preset specific age according to a preset cutting method to obtain a plurality of prefabricated high-strength concrete component test samples; Step S5, using ion chromatography to determine the chloride ion concentration in each prefabricated high-strength concrete component test sample, and determining the chloride ion penetration resistance at the nodes of the prefabricated high-strength concrete component based on the obtained chloride ion concentrations.

[0007] Preferably, in step S4, the following steps are included: Step S4.1, cutting the precast high-strength concrete component that has been soaked to a preset specific age along a direction perpendicular to the plane where the binder in the precast high-strength concrete component is located, to obtain a first cutting sampling sample with a preset thickness; wherein the cutting plane formed by cutting in step S4.1 is parallel to the horizontal plane; Step S4.2, cutting the first cut sample along the plane where the adhesive on the first cut sample is located, to obtain two independent second cut sample samples; Step S4.3, cutting along the center line located on the second cutting sample and perpendicular to the plane where the adhesive is located, to obtain two independent third cutting samples; wherein the cutting plane formed by cutting in step S4.3 is perpendicular to the horizontal plane; Step S4.4, using sandpaper to grind off the adhesive on the plane where the adhesive is located on each of the third-cut sampling samples, and correspondingly obtaining two third-cut sampling samples without the adhesive; Step S4.5, cutting the third cutting sampling sample from which the binder has been removed multiple times along a direction perpendicular to the plane where the binder is located according to a preset interval thickness to obtain multiple prefabricated high-strength concrete component test samples corresponding to the third cutting sampling sample; wherein the obtained prefabricated high-strength concrete component test samples correspond to the binder positions on the prefabricated high-strength concrete components one by one; wherein the cutting plane formed by cutting in step S4.5 is perpendicular to the horizontal plane.

[0008] Improved, in the method for testing the chloride ion penetration resistance of prefabricated high-strength concrete component nodes, in step S5, the process of using ion chromatography to respectively determine the chloride ion concentration in each prefabricated high-strength concrete component test sample comprises the following steps: Step a1, selecting a chloride standard stock solution with a mass concentration of 1000 mg / L and deionized water; Step a2, select 200ml of a chloride standard stock solution with a mass concentration of 1000 mg / L, and place the 200ml chloride standard stock solution in a 1000ml volumetric flask, then dilute the chloride standard stock solution in the 1000ml volumetric flask with the prepared deionized water and make it to the mark to prepare a chloride ion mass concentration of 200mg / L chloride ion standard working solution; Step a3, prepare 6 100ml volumetric flasks, and respectively pipette 0ml of chloride ion standard solution, 1ml of chloride ion standard solution, 2ml of chloride ion standard solution, 5ml of chloride ion standard solution, 10ml of chloride ion standard solution and 20ml of chloride ion standard solution into the corresponding 100ml volumetric flasks, and dilute the chloride ion standard solution in the corresponding volumetric flask with the prepared deionized water to the mark, and prepare 6 chloride ion standard solutions with different chloride ion mass concentrations; wherein each volume of chloride ion standard solution pipetted corresponds to the 100ml volumetric flask one by one; Step a4, injecting the obtained chloride ion standard solutions into the ion chromatograph in order from low to high chloride ion mass concentration, and recording the ion chromatography data corresponding to the chloride ion standard solution of each chloride ion mass concentration, and then drawing a standard curve with the chloride ion mass concentration as the horizontal axis and the ion chromatography data as the vertical axis; wherein the ion chromatography data is the peak area or peak height.

[0009] Further improved, in the present invention, the method for testing the chloride ion penetration resistance of the prefabricated high-strength concrete component nodes further includes the following steps b1 to b7: Step b1, respectively collecting a first preset mass of powder of each of the prefabricated high-strength concrete component test samples; wherein the powder of the prefabricated high-strength concrete component test samples is powder generated when a drilling machine drills holes in the prefabricated high-strength concrete component test samples; Step b2, using a standard sieve with a sieve hole diameter of 0.63 mm to sieve the collected prefabricated high-strength concrete component test sample powders to obtain prefabricated high-strength concrete component test sample powders remaining after sieving; Step b3, drying the prefabricated high-strength concrete component test sample powders remaining after each screening, and obtaining dried prefabricated high-strength concrete component test sample powders; Step b4, weighing the second preset mass of each dried prefabricated high-strength concrete component test sample powder respectively, and putting the weighed dried prefabricated high-strength concrete component test sample powder respectively into a corresponding volumetric flask filled with 200 mL of distilled water and soaking for 24 hours; wherein the dried prefabricated high-strength concrete component test sample powder corresponds to the volumetric flask filled with 200 mL of distilled water one by one; Step b5, using a microporous filter membrane with a pore size of 0.45 μm to filter the liquid in each volumetric flask containing 200 mL of distilled water that has been soaked for 24 hours, and selecting two 20 mL portions of the filtrate obtained after filtering the liquid in each volumetric flask; Step b6, replacing the dried prefabricated high-strength concrete component test sample powder in step b4 with deionized water, and then performing steps b4 to b5 to obtain a laboratory blank sample, and injecting the treated laboratory blank sample into an ion chromatograph to measure the ion chromatographic data corresponding to the anions in the laboratory blank sample; Step b7, treating the two selected 20 mL filtrates with a C18 column and a Na column respectively, and injecting the treated 20 mL filtrates into an ion chromatograph respectively to determine the chloride ion concentration in the corresponding prefabricated high-strength concrete component test sample; wherein the chloride ion concentration in the prefabricated high-strength concrete component test sample is calculated as follows: ρ = (h - h0 - a) / nb; Wherein, ρ is the mass concentration of chloride ions in the prefabricated high-strength concrete component test sample, h is the ion chromatogram data corresponding to the chloride ions in the prefabricated high-strength concrete component test sample, h0 is the ion chromatogram data corresponding to the anions in the laboratory blank sample, a is the intercept of the standard curve, n is the molar mass of the chloride ions, and b is the slope of the standard curve.

[0010] Optionally, in the method for testing the chloride ion penetration resistance of prefabricated high-strength concrete component nodes, the ion chromatography data in step b7 is peak area or peak height.

[0011] In order to more realistically reflect the actual engineering situation, in step S2, before the two high-strength concrete test block samples are bonded, a bolt connection is added between the two high-strength concrete test block samples. In a specific implementation, other connection methods can be added at the nodes according to the test requirements to construct prefabricated high-strength concrete components with different connection forms including bonding and bolt connection.

[0012] Optionally, in step S2, before the two high-strength concrete test block samples are bonded, the two high-strength concrete test block samples are poured with concrete for the second time. In a specific implementation, other connection methods can be added at the nodes according to test requirements to construct prefabricated high-strength concrete components with different connection forms including bonding, bolt connection, and secondary pouring of concrete.

[0013] Compared with the prior art, the advantages of the present invention are: First, the invention provides a method for testing the chloride ion penetration resistance of prefabricated high-strength concrete component nodes. Two high-strength concrete samples of the same size are bonded with an adhesive to obtain a high-strength concrete structure sample. The structure sample is immersed in a high-chloride content solution for a preset specific age, and then cut according to a preset cutting method to obtain a plurality of prefabricated high-strength concrete component test samples. The preset cutting method is to cut the structure sample along the plane where the adhesive is located to obtain a first cutting sampling sample, cut the first cutting sampling sample along the plane where the adhesive is located on the first cutting sampling sample to obtain a second cutting sampling sample, and then cut along the center line of the second cutting sampling sample. The third cutting sampling sample is obtained by cutting, the surface binder of the third cutting sampling sample is removed, and then the third cutting sampling sample is cut multiple times according to a preset interval thickness to obtain multiple high-strength concrete component test samples, and the chloride ion mass concentration in each high-strength concrete component test sample is determined by ion chromatography. Since each high-strength concrete component test sample corresponds to a component node of the high-strength concrete component at a different depth in the chlorine-containing solution, the chloride ion penetration resistance at the node of the prefabricated high-strength concrete component is accurately determined, which solves the problem that the existing chloride ion penetration capacity test method is not applicable and cannot determine the chloride ion penetration resistance at the node of the prefabricated concrete structure component; Secondly, the method for testing the chloride ion penetration resistance of the nodes of precast high-strength concrete components of the present invention ensures that the precast high-strength concrete component test samples corresponding to the precast high-strength concrete components at different depth nodes are obtained by cutting the cutting object each time in succession along different directions, and the different depth nodes here represent the joint areas located at different positions in the precast high-strength concrete components, thereby ensuring that the chloride ion mass concentration in each precast high-strength concrete component test sample finally obtained is the penetration performance of the nodes of the precast high-strength concrete components at different depths in the chlorine-containing solution, which is more in line with the actual application environment of the precast high-strength concrete components. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic flow chart of a method for testing the chloride ion penetration resistance of a prefabricated high-strength concrete component node in an embodiment of the present invention; Figure 2 Schematic diagram of the structure of two prepared high-strength concrete samples; Figure 3 It is a schematic diagram of the structure of a high-strength concrete structure sample; Figure 4 This is a schematic diagram of the structure of the sample taken by cutting for the first time; Figure 5 This is a schematic diagram of the structure of the sample taken by cutting for the second time; Figure 6 This is a schematic diagram of the structure of the sample taken by cutting for the third time; Figure 7It is a schematic diagram of the structure of multiple high-strength concrete component test samples obtained; Figure 8 Schematic diagram of the relationship between the chloride ion mass concentration in the high-strength concrete component test samples obtained under the preset specific age condition of 14 days and the node depth of the high-strength concrete structural component in Example 1, Example 2, Comparative Example 1 and Comparative Example 2; Fig. 9 Schematic diagram of the relationship between the chloride ion mass concentration in the high-strength concrete component test samples obtained under the preset specific age condition of 28 days and the node depth of the high-strength concrete structural component in Example 1, Example 2, Comparative Example 1 and Comparative Example 2. DETAILED DESCRIPTION

[0015] The present invention is further described in detail below with reference to the accompanying drawings. Embodiment 1

[0016] This embodiment provides a method for testing the chloride ion penetration resistance of prefabricated high-strength concrete component nodes. Figure 1 As shown, the method for testing the chloride ion penetration resistance of prefabricated high-strength concrete component nodes in this embodiment includes the following steps S1 to S5: Step S1, prepare two high-strength concrete test blocks 1 of the same size of 100mm*100mm*100mm, and demould each high-strength concrete test block to obtain two high-strength concrete test block samples; specifically, in this embodiment, the two prepared high-strength concrete test blocks are in the shape of cubes, see Figure 2 As shown in; Step S2, using an adhesive M epoxy resin to bond two high-strength concrete test blocks 1 on their contact surfaces to obtain a prefabricated high-strength concrete component S containing the adhesive; wherein the bonding point of the two high-strength concrete test block samples is the component node of the prefabricated high-strength concrete component; Step S3, immersing the prefabricated high-strength concrete component S in a solution with a high chloride content at a temperature of 20° C. for a preset specific age of 14 days; wherein the solution with a high chloride content here refers to a sodium chloride solution with a mass fraction of 30%; For example, in order to more realistically reflect the transmission process of chloride ions in the flowing solution, in this embodiment, a water pump circulation system or a fan disturbance device can be used to drive the high-chloride content solution to flow, so as to enhance the migration and penetration behavior of chloride ions in the prefabricated high-strength concrete component; Step S4.1, cutting the prefabricated high-strength concrete component that has been soaked to a preset specific age along a direction perpendicular to the plane where the binder is located in the prefabricated high-strength concrete component S, to obtain a first cut sample S1 with a preset thickness of 30 mm; wherein the structure of the first cut sample is shown in Figure 4 The corresponding cutting direction in step S4.1 is shown in Figure 3 The direction of the arrow in; Step S4.2, cutting the first cut sample along the plane where the adhesive M on the first cut sample S1 is located, to obtain two independent second cut sample S2; wherein the structure of the obtained second cut sample is shown in FIG. Figure 5 The corresponding cutting direction in step S4.2 is shown in Figure 4 The direction of the arrow in; Step S4.3, cutting along the center line of the second cutting sample S2 to obtain two independent third cutting samples; wherein the corresponding cutting direction in step S4.3 is shown in Figure 5 The direction of the arrow in; Step S4.4, using sandpaper to grind off the adhesive on the plane where the adhesive is located on each of the third cutting samples, and correspondingly obtaining two third cutting samples S3 without the adhesive; wherein the structure of the third cutting samples without the adhesive is shown in FIG. Figure 6 As shown; here, 80-120 mesh sandpaper is used to grind off the adhesive on the plane where the adhesive is located on each third-cut sample, and grind until the surface of the third-cut sample is uniform and free of loose particles; Step S4.5, cutting the third cutting sample S3 from which the binder has been removed multiple times along a direction perpendicular to the plane where the binder M is located at a preset interval thickness of 5 mm, to obtain multiple prefabricated high-strength concrete component test samples S4 corresponding to the third cutting sample S3 from which the binder should be removed; wherein the prefabricated high-strength concrete component test samples correspond to the binder positions on the prefabricated high-strength concrete components one by one; the structures of the multiple prefabricated high-strength concrete component test samples obtained refer to Figure 7 The corresponding cutting direction in step S4.5 is shown in Figure 6 The direction of the arrow in; Step S5, using ion chromatography to determine the chloride ion mass concentration in each prefabricated high-strength concrete component test sample, and determining the chloride ion penetration resistance at the nodes of the prefabricated high-strength concrete component based on the obtained chloride ion mass concentrations.

[0017] For example, in this embodiment, with respect to the above step S5, the process of using ion chromatography to respectively determine the chloride ion concentration in each prefabricated high-strength concrete component test sample includes the following steps a1 to a4: Step a1, selecting a chloride standard stock solution with a mass concentration of 1000 mg / L and deionized water; Step a2, select 200ml of a chloride standard stock solution with a mass concentration of 1000 mg / L, and place the 200ml chloride standard stock solution in a 1000ml volumetric flask, then dilute the chloride standard stock solution in the 1000ml volumetric flask with the prepared deionized water and make it to the mark to prepare a chloride ion mass concentration of 200mg / L chloride ion standard working solution; Step a3, prepare 6 100ml volumetric flasks, and respectively pipette 0ml of chloride ion standard solution, 1ml of chloride ion standard solution, 2ml of chloride ion standard solution, 5ml of chloride ion standard solution, 10ml of chloride ion standard solution and 20ml of chloride ion standard solution into the corresponding 100ml volumetric flasks, and dilute the chloride ion standard solution in the corresponding volumetric flask with the prepared deionized water to the mark, and prepare 6 chloride ion standard solutions with different chloride ion mass concentrations; wherein each volume of chloride ion standard solution pipetted corresponds to the 100ml volumetric flask one by one; Step a4, injecting the obtained chloride ion standard solutions into the ion chromatograph in order from low to high chloride ion mass concentration, and recording the ion chromatography data corresponding to the chloride ion standard solution of each chloride ion mass concentration, and then drawing a standard curve with the chloride ion mass concentration as the horizontal axis and the ion chromatography data as the vertical axis; wherein the ion chromatography data is the peak area or peak height.

[0018] In addition, based on the execution of the above steps a1 to a4, the method for testing the chloride ion penetration resistance of the prefabricated high-strength concrete component nodes of this embodiment further includes: Step b1, respectively collecting powders of the prefabricated high-strength concrete component test samples with a first preset mass of 30 g; that is, the mass of the collected powders of the prefabricated high-strength concrete component test samples is 30 g; wherein the powders of the prefabricated high-strength concrete component test samples are powders generated when the drilling machine drills holes in the prefabricated high-strength concrete component test sample S4. In this embodiment, the drilling machine drills holes on the plane where the original binder is located on the prefabricated high-strength concrete component test sample S4, and the heights of the holes drilled in the prefabricated high-strength concrete component test samples are consistent; Step b2, using a standard sieve with a sieve hole diameter of 0.63 mm to sieve the collected prefabricated high-strength concrete component test sample powders to obtain prefabricated high-strength concrete component test sample powders remaining after sieving; Step b3, drying the high-strength concrete component test sample powders remaining after each screening, and obtaining dried prefabricated high-strength concrete component test sample powders; wherein the prefabricated high-strength concrete component test sample powders remaining after screening are dried separately, and a certain time interval (such as one hour) is maintained until the mass difference of the powder in two tests does not exceed 0.1%, and the prefabricated high-strength concrete component test sample powders are considered to be fully dried; Step b4, weighing 20 g of each dried prefabricated high-strength concrete component test sample powder respectively, and putting each weighed dried prefabricated high-strength concrete component test sample powder into a corresponding volumetric flask filled with 200 mL of distilled water, stirring evenly and soaking for 24 hours; wherein the dried prefabricated high-strength concrete component test sample powder corresponds to the volumetric flask filled with 200 mL of distilled water one by one; Step b5, using a microporous filter membrane with a pore size of 0.45 μm to filter the liquid in each volumetric flask containing 200 mL of distilled water that has been soaked for 24 hours, and selecting two 20 mL portions of the filtrate obtained after filtering the liquid in each volumetric flask; Step b6, replacing the dried prefabricated high-strength concrete component test sample powder in step b4 with deionized water, and then performing steps b4 to b5 to obtain a laboratory blank sample, and injecting the treated laboratory blank sample into an ion chromatograph to measure the ion chromatographic data corresponding to the anions in the laboratory blank sample; Step b7, the two selected 20 mL filtrates are treated with a C18 column and a Na column respectively to remove the influence of hydrophobic compounds, heavy metals and transition metals, and the treated 20 mL filtrates are respectively injected into an ion chromatograph to determine the chloride ion concentration in the corresponding prefabricated high-strength concrete component test sample; wherein the chloride ion concentration in the prefabricated high-strength concrete component test sample is calculated as follows: ρ=(h-h0-a) / nb; Formula (1) Wherein, ρ is the mass concentration of chloride ions in the prefabricated high-strength concrete component test sample, h is the ion chromatogram data corresponding to chloride ions in the prefabricated high-strength concrete component test sample, h0 is the ion chromatogram data corresponding to anions in the laboratory blank sample, a is the intercept of the standard curve, n is the molar mass of chloride ions, and b is the slope of the standard curve. For example, the molar mass n of chloride ions is 35.5 g / mol. Wherein, the ion chromatogram data in step b7 here is the peak area or peak height.

[0019] In this embodiment, samples are taken from the planes where the original binder is located on different high-strength concrete component test samples S4, and the different prefabricated high-strength concrete component test samples S4 correspond to different depths at the nodes of the prefabricated high-strength concrete component, and the measured chloride ion mass concentrations of the different prefabricated high-strength concrete component test samples S4 also correspond to the chloride ion mass concentrations at different depths of the prefabricated high-strength concrete component nodes. Embodiment 2

[0020] The difference between this embodiment and the first embodiment is only the soaking temperature. According to the method in the first embodiment, two high-strength concrete test blocks of 100 mm×100 mm×100 mm are prepared, and the two high-strength concrete test blocks are connected by using epoxy resin as a binder to obtain a prefabricated high-strength concrete member containing a binder, and then immersed in a high-chlorine content solution at 60°C for a preset specific age of 14 days, and a prefabricated high-strength concrete member with a thickness of 30 mm is cut for testing. After the epoxy resin on the surface of the third-cut sample without the binder is polished off with sandpaper, the third-cut sample is cut multiple times along the direction perpendicular to the plane where the binder is located at a preset interval thickness of 5 mm to obtain multiple prefabricated high-strength concrete member test samples (the epoxy resin binder on the surface of the prefabricated high-strength concrete member test samples has been polished off), and then the chloride ion mass concentration in each prefabricated high-strength concrete member test sample is calculated by formula (1).

[0021] Comparative Example 1 The difference between this embodiment and the first embodiment is that the sampling position on the prefabricated high-strength concrete component test sample is different. According to the method in the first embodiment, two high-strength concrete test blocks of 100mm×100mm×100mm are prepared, and the two high-strength concrete test blocks are connected by using epoxy resin as a binder to obtain a prefabricated high-strength concrete component containing a binder, and then immersed in a high-chlorine content solution at 20°C for a preset specific age of 14d, and a 30mm thick prefabricated high-strength concrete component is cut for testing. After the epoxy resin on the surface of the third-cut sample without the binder is polished off with sandpaper, the third-cut sample is cut multiple times in a direction perpendicular to the plane where the binder is located at a preset interval thickness of 5mm to obtain multiple prefabricated high-strength concrete component test samples (the epoxy resin binder on the surface of the prefabricated high-strength concrete component test sample has been polished off). In this embodiment, the drilling machine drills holes on the non-binder plane and non-immersed surface of the prefabricated high-strength concrete component test sample S4, for example, Figure 7 The bottom surface of the prefabricated high-strength concrete component test sample S4 is drilled to obtain the prefabricated high-strength concrete component test sample powder; and then the chloride ion mass concentration at the middle position of the prefabricated high-strength concrete component is calculated by formula (1).

[0022] Comparative Example 2 The difference between this embodiment and the second embodiment is that the sampling position on the prefabricated high-strength concrete component test sample is different. According to the method in the second embodiment, two high-strength concrete test blocks of 100mm×100mm×100mm are prepared, and the two high-strength concrete test blocks are connected by using epoxy resin as a binder to obtain a prefabricated high-strength concrete component containing a binder, and then immersed in a high-chlorine content solution at 60°C for a preset specific age of 14d, and a 30mm thick prefabricated high-strength concrete component is cut for testing. After the epoxy resin on the surface of the third cut sample without the binder is polished off with sandpaper, the third cut sample is cut multiple times in a direction perpendicular to the plane where the binder is located at a preset interval thickness of 5mm to obtain multiple prefabricated high-strength concrete component test samples (the epoxy resin binder on the surface of the prefabricated high-strength concrete component test sample has been polished off). In this embodiment, the drilling machine drills holes on the non-binder plane and non-immersed surface of the prefabricated high-strength concrete component test sample S4, for example, Figure 7 The bottom surface of the prefabricated high-strength concrete component test sample S4 is drilled to obtain the prefabricated high-strength concrete component test sample powder; and then the chloride ion mass concentration at the middle position of the prefabricated high-strength concrete component is calculated by formula (1).

[0023] For the data on the mass concentration of chloride ions in the samples obtained in the above-mentioned Example 1, Example 2, Comparative Example 1 and Comparative Example 2, see Figure 8 shown.

[0024] In addition, the preset specific age of the prefabricated high-strength concrete components containing binders immersed in the high-chlorine content solution at different temperatures is reset to 28 days, and then the chloride ion mass concentration in the respective prefabricated high-strength concrete component test samples is obtained again by referring to the above-mentioned Example 1, Example 2, Comparative Example 1 and Comparative Example 2. Among them, the chloride ion mass concentration data in the respective corresponding samples are specifically referred to Fig. 9 shown.

[0025] according to Figure 8 and 9 The chloride ion mass concentration results shown in the figure show that the chloride ion mass concentration at the nodes (i.e. the joint area) of the precast high-strength concrete components is significantly higher than that at the non-nodes (i.e. the non-joint area) of the precast high-strength concrete components. exist Figure 8In the present invention, under the curing condition of 20°C, the mass concentration of chloride ions at the non-nodes (i.e., non-joint areas) of the precast high-strength concrete component in Comparative Example 1 for 14 days is 0.0020 mol / L, while the mass concentration of chloride ions at the nodes of the precast high-strength concrete component in Example 1 for 14 days is 0.0028 mol / L; as the curing temperature increases, the obtained mass concentration of chloride ions increases, wherein the mass concentration of chloride ions at the non-nodes (i.e., non-joint areas) of the precast high-strength concrete component in Comparative Example 2 for 14 days is 0.0033 mol / L, and the mass concentration of chloride ions at the nodes (i.e., joint areas) of the precast high-strength concrete component in Example 2 for 14 days is 0.0045 mol / L.

[0026] Of course, the above changes in the chloride ion mass concentration at the nodes (i.e., joint areas) of precast high-strength concrete components are Fig. 9 It was presented again.

[0027] It can be seen from this that there is a higher risk of chloride ion infiltration at the nodes (i.e., joint areas) of precast high-strength concrete components. Therefore, during the design process of precast high-strength concrete components, special attention should be paid to the changes in chloride ion concentration at the nodes (i.e., joint areas) of precast high-strength concrete components to reduce the potential risk of chloride ion corrosion.

[0028] Although the preferred embodiments of the present invention are described in detail above, it should be clearly understood that various modifications and variations are possible for those skilled in the art. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for testing the chloride ion penetration resistance of prefabricated high-strength concrete component nodes, characterized in that: The following steps are involved: Step S1, preparing two high-strength concrete test blocks of the same size, and performing demoulding treatment on each high-strength concrete test block to obtain two high-strength concrete test block samples; Step S2, using an adhesive to bond two high-strength concrete test block samples on their contact surfaces to obtain a prefabricated high-strength concrete component containing the adhesive; wherein the bonding point of the two high-strength concrete test block samples is the component node of the prefabricated high-strength concrete component; Step S3, immersing the prefabricated high-strength concrete component in a solution with a high chloride content until a preset specific age; Step S4, cutting the prefabricated high-strength concrete components that have been soaked to a preset specific age according to a preset cutting method to obtain a plurality of prefabricated high-strength concrete component test samples; Step S5, using ion chromatography to determine the chloride ion concentration in each prefabricated high-strength concrete component test sample, and determining the chloride ion penetration resistance at the nodes of the prefabricated high-strength concrete component based on the obtained chloride ion concentrations.

2. The method for testing the chloride ion penetration resistance of prefabricated high-strength concrete component nodes according to claim 1, characterized in that: In step S4, the following steps are included: Step S4.1, cutting the precast high-strength concrete component that has been soaked to a preset specific age along a direction perpendicular to the plane where the binder in the precast high-strength concrete component is located, to obtain a first cutting sampling sample with a preset thickness; wherein the cutting plane formed by cutting in step S4.1 is parallel to the horizontal plane; Step S4.2, cutting the first cut sample along the plane where the adhesive on the first cut sample is located, to obtain two independent second cut sample samples; Step S4.3, cutting along the center line located on the second cutting sample and perpendicular to the plane where the adhesive is located, to obtain two independent third cutting samples; wherein the cutting plane formed by cutting in step S4.3 is perpendicular to the horizontal plane; Step S4.4, using sandpaper to grind off the adhesive on the plane where the adhesive is located on each of the third-cut sampling samples, and correspondingly obtaining two third-cut sampling samples without the adhesive; Step S4.5, cutting the third cutting sampling sample from which the binder has been removed multiple times along a direction perpendicular to the plane where the binder is located according to a preset interval thickness to obtain multiple prefabricated high-strength concrete component test samples corresponding to the third cutting sampling sample; wherein the obtained prefabricated high-strength concrete component test samples correspond to the binder positions on the prefabricated high-strength concrete components one by one; wherein the cutting plane formed by cutting in step S4.5 is perpendicular to the horizontal plane.

3. The method for testing the chloride ion penetration resistance of prefabricated high-strength concrete component nodes according to claim 2, characterized in that: In step S5, the process of using ion chromatography to determine the chloride ion concentration in each prefabricated high-strength concrete component test sample includes the following steps: Step a1, selecting a chloride standard stock solution with a mass concentration of 1000 mg / L and deionized water; Step a2, select 200ml of a chloride standard stock solution with a mass concentration of 1000 mg / L, and place the 200ml chloride standard stock solution in a 1000ml volumetric flask, then dilute the chloride standard stock solution in the 1000ml volumetric flask with the prepared deionized water and make it to the mark to prepare a chloride ion mass concentration of 200mg / L chloride ion standard working solution; Step a3, prepare 6 100ml volumetric flasks, and respectively pipette 0ml of chloride ion standard solution, 1ml of chloride ion standard solution, 2ml of chloride ion standard solution, 5ml of chloride ion standard solution, 10ml of chloride ion standard solution and 20ml of chloride ion standard solution into the corresponding 100ml volumetric flasks, and dilute the chloride ion standard solution in the corresponding volumetric flask with the prepared deionized water to the mark, and prepare 6 chloride ion standard solutions with different chloride ion mass concentrations; wherein each volume of chloride ion standard solution pipetted corresponds to the 100ml volumetric flask one by one; Step a4, injecting the obtained chloride ion standard solutions into the ion chromatograph in order from low to high chloride ion mass concentration, and recording the ion chromatography data corresponding to the chloride ion standard solution of each chloride ion mass concentration, and then drawing a standard curve with the chloride ion mass concentration as the horizontal axis and the ion chromatography data as the vertical axis; wherein the ion chromatography data is the peak area or peak height.

4. The method for testing the chloride ion penetration resistance of prefabricated high-strength concrete component nodes according to claim 3, characterized in that: Also includes: Step b1, respectively collecting a first preset mass of powder of each of the prefabricated high-strength concrete component test samples; wherein the powder of the prefabricated high-strength concrete component test samples is powder generated when a drilling machine drills holes in the prefabricated high-strength concrete component test samples; Step b2, using a standard sieve with a sieve hole diameter of 0.63 mm to sieve the collected prefabricated high-strength concrete component test sample powders to obtain prefabricated high-strength concrete component test sample powders remaining after sieving; Step b3, drying the prefabricated high-strength concrete component test sample powders remaining after each screening, and obtaining dried prefabricated high-strength concrete component test sample powders; Step b4, weighing the second preset mass of each dried prefabricated high-strength concrete component test sample powder respectively, and putting the weighed dried prefabricated high-strength concrete component test sample powder respectively into a corresponding volumetric flask filled with 200 mL of distilled water and soaking for 24 hours; wherein the dried prefabricated high-strength concrete component test sample powder corresponds to the volumetric flask filled with 200 mL of distilled water one by one; Step b5, using a microporous filter membrane with a pore size of 0.45 μm to filter the liquid in each volumetric flask containing 200 mL of distilled water that has been soaked for 24 hours, and selecting two 20 mL portions of the filtrate obtained after filtering the liquid in each volumetric flask; Step b6, replacing the dried prefabricated high-strength concrete component test sample powder in step b4 with deionized water, and then performing steps b4 to b5 to obtain a laboratory blank sample, and injecting the treated laboratory blank sample into an ion chromatograph to measure the ion chromatographic data corresponding to the anions in the laboratory blank sample; Step b7, treating the two selected 20 mL filtrates with a C18 column and a Na column respectively, and injecting the treated 20 mL filtrates into an ion chromatograph respectively to determine the chloride ion concentration in the corresponding prefabricated high-strength concrete component test sample; wherein the chloride ion concentration in the prefabricated high-strength concrete component test sample is calculated as follows: ρ = (h - h0 - a) / nb; Wherein, ρ is the mass concentration of chloride ions in the prefabricated high-strength concrete component test sample, h is the ion chromatogram data corresponding to the chloride ions in the prefabricated high-strength concrete component test sample, h0 is the ion chromatogram data corresponding to the anions in the laboratory blank sample, a is the intercept of the standard curve, n is the molar mass of the chloride ions, and b is the slope of the standard curve.

5. The method for testing the chloride ion penetration resistance of prefabricated high-strength concrete component nodes according to claim 4, characterized in that: The ion chromatography data in step b7 is peak area or peak height.

6. The method for testing the chloride ion penetration resistance of prefabricated high-strength concrete component nodes according to claim 1, characterized in that: In step S2, before the two high-strength concrete test block samples are subjected to bonding treatment, bolts are added between the two high-strength concrete test block samples for connection.

7. The method for testing the chloride ion penetration resistance of prefabricated high-strength concrete component nodes according to claim 1, characterized in that: In step S2, before the two high-strength concrete test block samples are subjected to bonding treatment, concrete is poured between the two high-strength concrete test block samples for a second time.

Images