Test method for chloride ion penetration resistance of joints of precast high-strength concrete components

Abstract

The present invention relates to a method for testing the chloride ion penetration resistance of joints of precast high-strength concrete components. By bonding two high-strength concrete test blocks of the same size with an adhesive to obtain a precast high-strength concrete component, after soaking the precast high-strength concrete component in a solution with a high chloride content for a preset specific age, the precast high-strength concrete component that has been soaked to the preset specific age is cut according to a preset cutting method to obtain a plurality of precast high-strength concrete component test samples, and the ion chromatography method is used to determine the chloride ion mass concentration in each precast high-strength concrete component test sample, so as to accurately determine the chloride ion penetration resistance performance at the joints of the precast high-strength concrete components.

Description

Technical Field

[0001] The present invention relates to the field of inspection of precast high-strength concrete components, and particularly to a method for testing the chloride ion penetration resistance of joints of precast high-strength concrete components. Background Art

[0002] Chloride ion permeability is a key indicator for evaluating the durability and corrosion resistance of concrete, and is particularly important for concrete structures such as marine environmental engineering, bridge structures, and underground parking lots that are long-term exposed to chloride environments. The penetration of chloride ions inside the concrete will cause two aspects of damage effects: on the one hand, the chloride ions react with the concrete components to cause expansion stress, which in turn causes cracking of the concrete structure and deterioration of mechanical properties; on the other hand, the chloride ions penetrate to the surface of the steel bars to damage the passivation film, inducing electrochemical corrosion of the steel bars, and finally causing durability damages such as cracking and spalling of the concrete protective layer. This dual damage mechanism significantly reduces the service life and safety performance of the concrete structure. For high-strength concrete, although high-strength concrete itself has excellent chloride ion penetration resistance, due to construction process limitations, it is impossible to achieve complete water tightness at the joint of the components, resulting in the dry joint becoming a weak link for chloride ion erosion.

[0003] Chinese Patent Application CN118758832A discloses a method for testing the chloride ion penetration resistance of concrete. This method first immerses the concrete specimen in a chloride ion-containing solution and stands for a set time, and then breaks the specimen to obtain two fresh fracture surfaces. The color reaction is carried out by spraying silver nitrate solution on the fracture surface; the image acquisition technology is used to distinguish the colored area and the uncolored area on the fracture surface. Based on the image analysis, the diffusion area ratio and the equivalent diffusion depth are calculated. The test method of this invention has good adaptability, accurate and reliable results, and is applicable to concrete with large-size aggregates.

[0004] However, the method for testing the chloride ion penetration resistance of concrete disclosed in the above-mentioned invention patent application CN118758832A has deficiencies: Although it can test the chloride ion penetration resistance of concrete, its test object is limited to a single concrete specimen, and the particularity of the connection nodes of precast components in actual engineering is not fully considered, resulting in obvious limitations. Generally speaking, there are usually two ways to connect small-sized components with limited space (such as high-strength concrete formwork): one is to use adhesives to connect different components, and the other is to use the method of secondary pouring for connection. For the nodes connected by adhesives, under the long-term action of environmental factors (such as temperature, humidity, and wind speed, etc.), microcracks are likely to occur in the interface area, forming a rapid chloride ion penetration channel, significantly accelerating the erosion process. For the nodes connecting new and old concrete, due to the existence of the interfacial transition zone, its porosity and chloride ion diffusion coefficient are often 30% - 50% higher than those of the bulk concrete, becoming a weak link in durability. This defect makes it difficult for the method in CN118758832A to accurately reflect the anti-erosion performance of similar components under actual service conditions, especially unable to obtain the chloride ion erosion data of this key weak part of the node. This defect will lead to a significant deviation between the durability evaluation results based on this method and the service life of actual components, thus affecting the safety and long-term performance prediction of engineering structures. 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 the nodes of precast high-strength concrete components, which can test the chloride ion penetration resistance of the nodes of precast high-strength concrete components in view of the above-mentioned prior art.

[0006] The technical solution adopted by the present invention to solve the above technical problem is as follows: A method for testing the chloride ion penetration resistance of the nodes of precast high-strength concrete components, comprising the following steps:

[0007] Step S1, prepare two high-strength concrete test blocks with the same size respectively, and after demolding each high-strength concrete test block, two high-strength concrete test block samples are obtained;

[0008] Step S2, bond the two high-strength concrete test block samples on their contact surfaces with an adhesive to obtain a precast high-strength concrete component containing the adhesive; wherein, the bonded part of the two high-strength concrete test block samples is the component node of the precast high-strength concrete component;

[0009] Step S3, immerse the precast high-strength concrete component in a solution with a high chloride content and immerse it until a preset specific age;

[0010] Step S4, cut the precast high-strength concrete component that has been immersed until the preset specific age according to a preset cutting method to obtain a plurality of precast high-strength concrete component test samples;

[0011] Step S5: Determine the chloride ion concentration in the test samples of each precast high-strength concrete member by ion chromatography, and determine the chloride ion penetration resistance at the joints of the precast high-strength concrete members based on the obtained chloride ion concentrations.

[0012] Preferably, in step S4, the following steps are included:

[0013] Step S4.1: Cut the precast high-strength concrete member that has been immersed to a preset specific age along the direction perpendicular to the plane where the binder is located in the precast high-strength concrete member to obtain a first cut sampling sample with a preset thickness; wherein, the cutting plane formed in step S4.1 is parallel to the horizontal plane.

[0014] Step S4.2: Cut the first cut sampling sample along the plane where the binder is located on the first cut sampling sample to obtain two independent second cut sampling samples.

[0015] Step S4.3: Cut along the center line located on the second cut sampling sample and perpendicular to the plane where the binder is located to obtain two independent third cut sampling samples; wherein, the cutting plane formed in step S4.3 is perpendicular to the horizontal plane.

[0016] Step S4.4: Use sandpaper to grind off the binder on the plane where the binder is located on each third cut sampling sample respectively to obtain two third cut sampling samples without binder correspondingly.

[0017] Step S4.5: Cut the third cut sampling sample without binder along the direction perpendicular to the plane where the binder is located at a preset interval thickness for multiple times to obtain multiple test samples of precast high-strength concrete members corresponding to the third cut sampling sample; wherein, the obtained test samples of precast high-strength concrete members correspond one-to-one to the positions of the binder on the precast high-strength concrete member; wherein, the cutting plane formed in step S4.5 is perpendicular to the horizontal plane.

[0018] Improved, in the method for testing the chloride ion penetration resistance of the joints of the precast high-strength concrete members, in step S5, the process of determining the chloride ion concentration in each test sample of the precast high-strength concrete member by ion chromatography includes the following steps:

[0019] Step a1: Select a chloride standard stock solution with a mass concentration of 1000 mg / L and deionized water.

[0020] Step a2: Select 200 ml of a chloride standard stock solution with a mass concentration of 1000 mg / L, place this 200 ml of chloride standard stock solution in a 1000 ml volumetric flask, and then dilute the chloride standard stock solution in the 1000 ml volumetric flask with the prepared deionized water and make up the volume to the mark to prepare a chloride standard working solution with a chloride ion mass concentration of 200 mg / L;

[0021] Step a3: Prepare 6 100 ml volumetric flasks, and respectively pipette 0 ml, 1 ml, 2 ml, 5 ml, 10 ml, and 20 ml of the chloride standard working solution into their corresponding 100 ml volumetric flasks, and dilute the chloride standard working solution in the corresponding volumetric flask with the prepared deionized water and make up the volume to the mark to respectively prepare 6 chloride standard solutions with different chloride ion mass concentrations; among them, the volumes of the chloride standard working solution pipetted each correspond one-to-one with the 100 ml volumetric flasks;

[0022] Step a4: Inject the obtained chloride standard solutions into the ion chromatograph in sequence according to the order of increasing chloride ion mass concentration, and respectively record the ion chromatographic data corresponding to each chloride standard solution with a chloride ion mass concentration, and then plot a standard curve with the chloride ion mass concentration as the abscissa and the ion chromatographic data as the ordinate; among them, the ion chromatographic data is the peak area or the peak height.

[0023] Furthermore, in this invention, the method for testing the chloride ion penetration resistance of the precast high-strength concrete member joints further includes the following steps b1 to b7:

[0024] Step b1: Respectively collect powders of each of the precast high-strength concrete member test samples with a first preset mass; among them, the powders of the precast high-strength concrete member test samples are the powders generated when drilling the precast high-strength concrete member test samples with a drilling machine;

[0025] Step b2: Screen the powders of each of the collected precast high-strength concrete member test samples with a standard sieve with a screen hole diameter of 0.63 mm to respectively obtain the powders of the precast high-strength concrete member test samples remaining after screening;

[0026] Step b3: Respectively dry the powders of the precast high-strength concrete member test samples remaining after screening to correspondingly obtain the dried powders of the precast high-strength concrete member test samples;

[0027] Step b4: Weigh the powders of the precast high-strength concrete component test samples after drying, each with a second preset mass, and respectively put the weighed powders of the precast high-strength concrete component test samples after drying into the corresponding volumetric flasks filled with 200 mL of distilled water and soak them for 24 h; among them, the powders of the precast high-strength concrete component test samples after drying correspond one-to-one with the volumetric flasks filled with 200 mL of distilled water;

[0028] Step b5: Filter the liquids in the volumetric flasks filled with 200 mL of distilled water that have been soaked for 24 h with a microporous filter membrane with a pore size of 0.45 um, and select two 20-mL filtrates from the filtrates obtained after filtering the liquids in each volumetric flask;

[0029] Step b6: Replace the powders of the precast high-strength concrete component test samples after drying in Step b4 with deionized water, and then perform Steps b4 to b5 again to obtain a laboratory blank sample, and inject the processed laboratory blank sample into an ion chromatograph to measure the ion chromatographic data corresponding to the anions in the laboratory blank sample;

[0030] Step b7: Treat the two selected 20-mL filtrates respectively with a C18 column and a Na column, and inject the treated 20-mL filtrates into an ion chromatograph respectively to measure the chloride ion concentration in the corresponding precast high-strength concrete component test samples; among them, the calculation method of the chloride ion concentration in the precast high-strength concrete component test samples is as follows:

[0031] ρ=(h - h0 - a) / nb;

[0032] where ρ is the chloride ion mass concentration in the precast high-strength concrete component test sample, h is the ion chromatographic data corresponding to the chloride ions in the precast high-strength concrete component test sample, h0 is the ion chromatographic data corresponding to the 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.

[0033] Optionally, in the method for testing the chloride ion penetration resistance of the precast high-strength concrete component joint, the ion chromatographic data in Step b7 is the peak area or the peak height.

[0034] To more truly reflect the actual engineering situation, in Step S2, before the two high-strength concrete test block samples are adhesively treated, bolt connections are added between the two high-strength concrete test block samples. In the specific implementation manner, other connection methods can be added at the joint according to the test requirements to construct precast high-strength concrete components including different connection forms such as bonding and bolt connection.

[0035] Optionally, in step S2, before the two high-strength concrete specimen samples are adhesively treated, concrete is cast between the two high-strength concrete specimen samples. In the specific implementation, other connection methods can be added at the joints according to the test requirements to construct precast high-strength concrete components including different connection forms such as bonding, bolt connection, and secondary concrete casting.

[0036] Compared with the prior art, the advantages of the present invention are as follows:

[0037] First, the method for testing the chloride ion penetration resistance of the joints of precast high-strength concrete components of the present invention obtains a high-strength concrete structure sample by bonding two high-strength concrete samples of the same size with an adhesive. After soaking the structure sample in a high-chloride-content solution until a preset specific age, it is cut according to a preset cutting method to obtain multiple precast high-strength concrete component test samples. The preset cutting method is specifically to cut the structure sample along the plane where the adhesive is located to obtain the first cutting and sampling sample, cut the first cutting and sampling sample along the plane where the adhesive is located on the first cutting and sampling sample to obtain the second cutting and sampling sample, and then cut the second cutting and sampling sample along the center line to obtain the third cutting and sampling sample. Remove the surface adhesive of the third cutting and sampling sample, and then cut the third cutting and sampling sample multiple times at a preset interval thickness to obtain multiple high-strength concrete component test samples. The chloride ion mass concentration in each high-strength concrete component test sample is measured by ion chromatography. Since each high-strength concrete component test sample corresponds to different depths of the joints of the high-strength concrete component in the chloride-containing solution, the chloride ion penetration resistance at the joints of the precast high-strength concrete component is accurately determined, solving the deficiency that the existing chloride ion penetration ability test method cannot be applied and cannot measure the chloride ion penetration resistance at the joints of precast concrete structural components.

[0038] Second, the method for testing the chloride ion penetration resistance of the joints of precast high-strength concrete components of the present invention cuts each cutting object in different directions successively to ensure that precast high-strength concrete component test samples corresponding to the joints at different depths of the precast high-strength concrete component are obtained. Here, the joints at different depths represent the joint areas at different positions in the precast high-strength concrete component, so as to ensure that the chloride ion mass concentration in each finally obtained precast high-strength concrete component test sample is the penetration performance of the joints of the precast high-strength concrete component at different depths in the chloride-containing solution, which is more in line with the actual application environment of the precast high-strength concrete component. Description of the Drawings

[0039] Figure 1 It is a schematic flow chart of the method for testing the chloride ion penetration resistance of the joints of precast high-strength concrete components in the embodiment of the present invention;

[0040] Figure 2Schematic diagram of the structures of two prepared high-strength concrete samples;

[0041] Figure 3 Schematic diagram of the structure of a high-strength concrete structure sample;

[0042] Figure 4 Schematic diagram of the structure of the sample taken by the first cutting;

[0043] Figure 5 Schematic diagram of the structure of the sample taken by the second cutting;

[0044] Figure 6 Schematic diagram of the structure of the sample taken by the third cutting;

[0045] Figure 7 Schematic diagram of the structures of multiple obtained high-strength concrete component test samples;

[0046] Figure 8 Schematic diagram of the relationship between the chloride ion mass concentration and the joint depth of the high-strength concrete structure components in the high-strength concrete component test samples obtained under the preset specific age conditions of 14 days for Example 1, Example 2, Comparative Example 1, and Comparative Example 2;

[0047] Figure 9 Schematic diagram of the relationship between the chloride ion mass concentration and the joint depth of the high-strength concrete structure components in the high-strength concrete component test samples obtained under the preset specific age conditions of 28 days for Example 1, Example 2, Comparative Example 1, and Comparative Example 2. Detailed implementation manners

[0048] The present invention will be further described in detail below in conjunction with the accompanying drawings and examples. Example 1

[0049] This example provides a method for testing the chloride ion penetration resistance of a precast high-strength concrete component joint. Specifically, as shown in Figure 1 , the method for testing the chloride ion penetration resistance of the precast high-strength concrete component joint in this example includes the following steps S1 to S5:

[0050] Step S1, prepare two high-strength concrete test blocks 1 with the same size of 100 mm×100 mm×100 mm respectively. After demolding each high-strength concrete test block, two high-strength concrete test block samples are obtained. Specifically, in this example, the two prepared high-strength concrete test blocks are cube-shaped, as shown in Figure 2 ;

[0051] Step S2, bond two high-strength concrete specimens 1 on their contact surfaces using binder M epoxy resin to obtain a precast high-strength concrete member S with binder; wherein, the bonded part of the two high-strength concrete specimen samples is the member node of the precast high-strength concrete member.

[0052] Step S3, immerse the precast high-strength concrete member S in a solution with a high chloride content and immerse it at 20°C until 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%.

[0053] For example, to more realistically reflect the transport process of chloride ions in a flowing solution, in this embodiment, a water pump circulation system or a fan disturbance device can be used to drive the flow of the solution with a high chloride content to strengthen the migration and penetration behavior of chloride ions in the precast high-strength concrete member.

[0054] Step S4.1, cut the precast high-strength concrete member that has been immersed to the preset specific age in a direction perpendicular to the plane where the binder is located in the precast high-strength concrete member S to obtain a first cut sampling sample S1 with a preset thickness of 30 mm; wherein, for the structural condition of the obtained first cut sampling sample, see Figure 4 shown; the corresponding cutting direction in this step S4.1 is shown by the arrow direction in Figure 3 .

[0055] Step S4.2, cut the first cut sampling sample S1 along the plane where the binder M is located on the first cut sampling sample to obtain two independent second cut sampling samples S2; wherein, for the structural condition of the obtained second cut sampling samples, see Figure 5 shown; the corresponding cutting direction in this step S4.2 is shown by the arrow direction in Figure 4 .

[0056] Step S4.3, cut along the center line of the second cut sampling sample S2 to obtain two independent third cut sampling samples; wherein, the corresponding cutting direction in this step S4.3 is shown by the arrow direction in Figure 5 .

[0057] Step S4.4, use sandpaper to grind off the binder on the plane where the binder is located on each third cut sampling sample respectively to obtain two third cut sampling samples S3 without binder; wherein, for the structural condition of the obtained third cut sampling samples without binder, see Figure 6 shown; here, 80 - 120 mesh sandpaper is used to grind off the binder on the plane where the binder is located on each third cut sampling sample respectively, and grind until the surface of the third cut sampling sample is uniform and there are no loose particles.

[0058] Step S4.5, perform multiple cuts on the third cut sampling sample S3 from which the binder M has been removed at a preset interval thickness of 5 mm in a direction perpendicular to the plane where the binder M is located, to obtain a plurality of precast high-strength concrete member test samples S4 corresponding to the third cut sampling sample S3 from which the binder has been removed; wherein, the precast high-strength concrete member test samples correspond one-to-one with the positions of the binder on the precast high-strength concrete member; for the structural conditions of the obtained plurality of precast high-strength concrete member test samples, see Figure 7 as shown; the corresponding cutting direction in this step S4.5 is shown by the arrow direction in Figure 6 ;

[0059] Step S5, use ion chromatography to measure the chloride ion mass concentration in each precast high-strength concrete member test sample, and determine the chloride ion penetration resistance performance at the joints of the precast high-strength concrete members based on the obtained chloride ion mass concentrations.

[0060] For example, in this embodiment, for the above step S5, the process of using ion chromatography to measure the chloride ion concentration in each precast high-strength concrete member test sample respectively includes the following steps a1 to a4:

[0061] Step a1, select a chloride standard stock solution with a mass concentration of 1000 mg / L and deionized water.

[0062] Step a2, select 200 ml of the chloride standard stock solution with a mass concentration of 1000 mg / L, place the 200 ml chloride standard stock solution in a 1000 ml volumetric flask, and then dilute the chloride standard stock solution in the 1000 ml volumetric flask with the prepared deionized water and make up to the mark to prepare a chloride standard working solution with a chloride ion mass concentration of 200 mg / L.

[0063] Step a3, prepare 6 100 ml volumetric flasks, and respectively pipette 0 ml, 1 ml, 2 ml, 5 ml, 10 ml, and 20 ml of the chloride standard working solution into their corresponding 100 ml volumetric flasks, and dilute the chloride standard working solution in the corresponding volumetric flasks with the prepared deionized water and make up to the mark to prepare 6 chloride standard solutions with different chloride ion mass concentrations respectively; wherein, the pipetted volumes of the chloride standard working solution correspond one-to-one with the 100 ml volumetric flasks.

[0064] Step a4: Inject the obtained chloride ion standard solutions into the ion chromatograph in ascending order of chloride ion mass concentration, record the ion chromatographic data corresponding to each chloride ion standard solution with a specific chloride ion mass concentration, and then plot a standard curve with the chloride ion mass concentration as the abscissa and the ion chromatographic data as the ordinate; wherein, the ion chromatographic data is the peak area or peak height.

[0065] In addition, on the basis of performing the above steps a1 - a4, the method for testing the chloride ion penetration resistance of the joints of precast high-strength concrete members in this embodiment further includes:

[0066] Step b1: Collect powder samples of each precast high-strength concrete member test sample with a first preset mass of 30 g; that is, the mass of the powder samples of each precast high-strength concrete member test sample collected is 30 g; wherein, the powder sample of the precast high-strength concrete member test sample is the powder generated when a drilling machine drills the precast high-strength concrete member test sample S4. In this embodiment, the drilling machine drills on the plane where the original binder of the precast high-strength concrete member test sample S4 is located, and the drilling height of each precast high-strength concrete member test sample is the same.

[0067] Step b2: Screen the powder samples of each precast high-strength concrete member test sample collected with a standard sieve with a screen hole diameter of 0.63 mm to obtain the powder samples of the precast high-strength concrete member test sample remaining after screening.

[0068] Step b3: Dry the powder samples of each high-strength concrete member test sample remaining after screening to obtain the dried powder samples of the precast high-strength concrete member test sample; wherein, the powder samples of the precast high-strength concrete member test sample remaining after screening are dried separately, and at intervals of a certain time (such as one hour), until the mass difference of the powder is no more than 0.1% after two tests, then it is considered that the powder samples of the precast high-strength concrete member test sample are fully dried.

[0069] Step b4: Weigh the dried powder samples of each precast high-strength concrete member test sample with a second preset mass of 20 g, and put the weighed dried powder samples of each precast high-strength concrete member test sample into the corresponding volumetric flask containing 200 mL of distilled water, stir evenly and soak for 24 h; wherein, the dried powder samples of the precast high-strength concrete member test sample correspond one-to-one with the volumetric flasks containing 200 mL of distilled water.

[0070] Step b5: Filter the liquid in each volumetric flask containing 200 mL of distilled water that has been soaked for 24 h with a microporous filter membrane with a pore size of 0.45 μm, and select two 20 mL filtrates from the filtrate obtained after filtering the liquid in each volumetric flask.

[0071] Step b6: Replace the powder of the precast high-strength concrete component test sample after drying in step b4 with deionized water, and then repeat steps b4 to b5 to obtain a laboratory blank sample. Inject the processed laboratory blank sample into an ion chromatograph to measure the ion chromatographic data corresponding to the anions in the laboratory blank sample;

[0072] Step b7: Treat two selected 20 mL filtrates respectively with a C18 column and a Na column to remove the influence of hydrophobic compounds, heavy metals and transition metals. Inject the treated 20 mL filtrates into an ion chromatograph respectively to measure the chloride ion concentration in the corresponding precast high-strength concrete component test sample. The calculation method of the chloride ion concentration in the precast high-strength concrete component test sample is as follows:

[0073] ρ=(h - h0 - a) / nb; Equation (1)

[0074] Where ρ is the chloride ion mass concentration in the precast high-strength concrete component test sample, h is the ion chromatographic data corresponding to the chloride ions in the precast high-strength concrete component test sample, h0 is the ion chromatographic data corresponding to the 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 taken as 35.5 g / mol. Here, the ion chromatographic data in step b7 is the peak area or peak height.

[0075] In this embodiment, samples are taken from the plane where the original binder is located on different high-strength concrete component test samples S4. Different precast high-strength concrete component test samples S4 correspond to different depths at the joints of precast high-strength concrete components. The measured chloride ion mass concentrations of different precast high-strength concrete component test samples S4 also correspond to the chloride ion mass concentrations at different depths at the joints of precast high-strength concrete components. Example Two

[0076] The difference between this embodiment and the first embodiment lies only in the different soaking temperatures. According to the method in the first embodiment, two high-strength concrete specimens of 100mm×100mm×100mm are prepared, and the two high-strength concrete specimens are connected using epoxy resin as a binder to obtain a precast high-strength concrete member with a binder. Then, it is soaked in a solution with a high chloride content at 60°C until a preset specific age of 14 days. A 30mm-thick precast high-strength concrete member is cut for testing. After sanding off the epoxy resin on the surface of the third cut sampling sample without the binder, multiple cuts are made on the third cut sampling sample at a preset interval thickness of 5mm in a direction perpendicular to the plane where the binder is located to obtain multiple precast high-strength concrete member test samples (the epoxy resin binder on the surface of the precast high-strength concrete member test samples has been sanded off). Then, the chloride ion mass concentration in each precast high-strength concrete member test sample is calculated separately through Equation (1).

[0077] Comparative Example 1

[0078] The difference between this embodiment and the first embodiment lies only in the different sampling positions on the precast high-strength concrete member test samples. According to the method in the first embodiment, two high-strength concrete specimens of 100mm×100mm×100mm are prepared, and the two high-strength concrete specimens are connected using epoxy resin as a binder to obtain a precast high-strength concrete member with a binder. Then, it is soaked in a solution with a high chloride content at 20°C until a preset specific age of 14 days. A 30mm-thick precast high-strength concrete member is cut for testing. After sanding off the epoxy resin on the surface of the third cut sampling sample without the binder, multiple cuts are made on the third cut sampling sample at a preset interval thickness of 5mm in a direction perpendicular to the plane where the binder is located to obtain multiple precast high-strength concrete member test samples (the epoxy resin binder on the surface of the precast high-strength concrete member test samples has been sanded off). In this embodiment, a drilling machine drills holes in the non-binder plane and non-soaking surface of the precast high-strength concrete member test sample S4. For example, for Figure 7 drilling on the bottom surface of the precast high-strength concrete member test sample S4 in the middle to obtain the powder of the precast high-strength concrete member test sample; then, the chloride ion mass concentration at the middle position of the precast high-strength concrete member is calculated through Equation (1).

[0079] Comparative Example 2

[0080] The difference between this embodiment and the second embodiment lies only in the different sampling positions on the precast high-strength concrete component test samples. According to the method in the second embodiment, two high-strength concrete test blocks with dimensions of 100mm×100mm×100mm are prepared, and the two high-strength concrete test blocks are connected using epoxy resin as the binder to obtain a precast high-strength concrete component containing the binder. Then, it is immersed in a solution with a high chloride content at 60°C until the preset specific age of 14 days. A 30mm-thick precast high-strength concrete component is cut for testing. After sanding off the epoxy resin on the surface of the third cut sampling sample without the binder, multiple cuts are made on the third cut sampling sample at a preset interval thickness of 5mm along the direction perpendicular to the plane where the binder is located, obtaining multiple precast high-strength concrete component test samples (the epoxy resin binder on the surface of the precast high-strength concrete component test samples has been sanded off). In this embodiment, the drilling machine drills on the plane of the precast high-strength concrete component test sample S4 that is not the plane where the binder is located and not the immersed surface. For example, for Figure 7 the bottom surface of the precast high-strength concrete component test sample S4 in

[0081] The chloride ion mass concentration data in the respective samples obtained in the above-mentioned first embodiment, second embodiment, comparative example 1, and comparative example 2 are shown in Figure 8 as follows.

[0082] In addition, the preset specific age for the precast high-strength concrete component containing the binder to be immersed in a solution with a high chloride content at different temperatures is reset to 28 days, and then, referring to the methods of the above-mentioned first embodiment, second embodiment, comparative example 1, and comparative example 2, the chloride ion mass concentrations in the respective precast high-strength concrete component test samples are obtained again. Among them, the specific chloride ion mass concentration data in the respective corresponding samples are shown in Figure 9 as follows.

[0083] According to Figure 8 and 9 the shown chloride ion mass concentration results, it can be known that the chloride ion mass concentration at the joints (i.e., the joint area) of the precast high-strength concrete components is significantly higher than that at the non-joints (i.e., the non-joint area) of the precast high-strength concrete components. Among them:

[0084] In Figure 8Among them, under the curing condition of 20 °C, the chloride ion mass concentration at 14 days at the non-node (i.e., non-joint area) of the precast high-strength concrete member in Comparative Example 1 was 0.0020 mol / L, while the chloride ion mass concentration at 14 days at the node of the precast high-strength concrete member in Example 1 was 0.0028 mol / L; as the curing temperature increased, the obtained chloride ion mass concentration increased somewhat. Among them, the chloride ion mass concentration at 14 days at the non-node (i.e., non-joint area) of the precast high-strength concrete member in Comparative Example 2 was 0.0033 mol / L, and the chloride ion mass concentration at 14 days at the node (i.e., joint area) of the precast high-strength concrete member in Example 2 was 0.0045 mol / L.

[0085] Of course, the above-described change situation of the chloride ion mass concentration at the node (i.e., joint area) of the precast high-strength concrete member is also presented again in Figure 9 it.

[0086] Thus, it can be seen that there is a high risk of chloride ion intrusion at the node (i.e., joint area) of the precast high-strength concrete member. Therefore, during the design process of the precast high-strength concrete member, special attention should be paid to the change of the chloride ion concentration at the position of the node (i.e., joint area) of the precast high-strength concrete member to reduce the potential risk of chloride ion erosion.

[0087] Although the preferred embodiments of the present invention have been described in detail above, it should be clearly understood that various changes and modifications can be made to the present invention for those skilled in the art. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within 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; 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.

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 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 standard working solution with a chloride ion mass concentration of 200mg / L; 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, inject the obtained chloride ion standard solutions into the ion chromatograph in order from low to high chloride ion mass concentration, and record the ion chromatography data corresponding to the chloride ion standard solution of each chloride ion mass concentration, and then draw 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.

3. The method for testing the chloride ion penetration resistance of prefabricated high-strength concrete component nodes according to claim 2, 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, sieving the collected prefabricated high-strength concrete component test sample powders respectively using a standard sieve with a sieve hole diameter of 0.63 mm 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.

4. The method for testing the chloride ion penetration resistance of prefabricated high-strength concrete component nodes according to claim 3, characterized in that: The ion chromatography data in step b7 is peak area or peak height.

5. 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.

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, concrete is poured between the two high-strength concrete test block samples for a second time.

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