An electroosmotic experimental device for testing the porosity of concrete / mortar

Abstract

This utility model discloses an electroosmotic experimental device for testing the porosity of concrete / mortar, including a sample chamber for placing the test specimen. Removable elastic sealing covers are provided at both ends of the sample chamber. An electrode plate is placed between each removable elastic sealing cover and the sample chamber, with two electrodes arranged in parallel. A copper core is welded perpendicularly to the center of each electrode plate. Lead holes are provided on the removable elastic sealing covers, and the two copper cores pass through these holes and are connected to a DC regulated power supply via wires. The symmetrical arrangement of the electrode plates and the use of removable elastic sealing covers allow for rapid removal of the electrode plates and copper cores after power failure, achieving metal-free sample transfer. The direct welding of the electrode plates to the copper cores, with the welding point precisely located at the center of the electrode plate, ensures the symmetry and uniformity of the electric field distribution. This solves the problems of sample damage, uneven electric field distribution, and low monitoring accuracy associated with traditional methods. Furthermore, the removable elastic sealing covers and electrode plates are reusable.

Description

Technical Field

[0001] This utility model belongs to the field of building material testing equipment, specifically relating to an electroosmotic experimental device for testing the porosity of concrete / mortar. Background Technology

[0002] The study of moisture migration characteristics in cement-based materials is crucial for the durability and structural performance of concrete. Traditional methods for exploring moisture migration in cement-based materials under an electric field rely on a core logic of using multiple parallel samples with controlled variables and point-based destruction sampling to transform the dynamic migration process into discrete data of "time-space-moisture content," which is then integrated to deduce the underlying patterns. However, after sample destruction, continuous in-situ monitoring of the moisture migration process under an electric field is impossible on the same sample. Furthermore, the destruction process may interfere with the original moisture distribution, making it difficult to capture the dynamic inflection point and the true migration patterns of moisture in micropores. The preparation and testing of multiple parallel samples also increases experimental costs and data dispersion. To further explore the moisture migration patterns in cement-based materials under an electric field, research typically relies on a series of experimental methods and equipment. Among these, the electrode materials and their arrangement significantly influence the experimental results in electroosmosis tests. Although electrodes exhibit superior electroosmotic performance under low voltage gradients, research on their standardized arrangement schemes is insufficient, leading to uneven electric field distribution during experiments and affecting testing accuracy. Utility Model Content

[0003] To address the aforementioned problems, the present invention aims to provide an electroosmotic experimental device for testing the porosity of concrete / mortar, which solves the problems of sample damage, uneven electric field distribution due to improper electrode arrangement, and inaccurate differentiation of moisture state caused by traditional methods.

[0004] This utility model is achieved through the following technical solution:

[0005] An electroosmotic experimental device for testing the porosity of concrete / mortar includes a sample chamber for placing test specimens. Removable elastic sealing covers are provided at both ends of the sample chamber. An electrode plate is disposed between each removable elastic sealing cover and the sample chamber. The two electrode plates are arranged in parallel. A copper core is welded perpendicularly to the center of each electrode plate. A lead wire hole is provided on the removable elastic sealing cover. The two copper cores pass through the lead wire hole and are connected to a DC regulated power supply via wires.

[0006] Furthermore, the bottom of the removable elastic sealing cover is provided with multiple conical positioning grooves for fixing the electrode plates.

[0007] Furthermore, the lead hole and the copper core are sealed with an elastic seal.

[0008] Furthermore, the electrode sheet is specifically a copper sheet with a diameter of 60 mm and a thickness of 2 mm.

[0009] Furthermore, the sample chamber is cylindrical with an outer diameter of 60 mm and an inner diameter of 58 mm.

[0010] Furthermore, the inner diameter of the removable elastic sealing cover 5 is 62mm.

[0011] Furthermore, the sample chamber is made of PC material.

[0012] Furthermore, the copper core has a diameter of 2mm and a length of 5cm.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] The electrode plates of this invention are symmetrically arranged and adopt a detachable elastic sealing cover structure. After power is cut off, the electrode plates and copper core can be quickly removed to achieve metallization-free sample transfer. The electrode plates and copper core are directly welded, and the welding point is precisely located at the center of the electrode plate, ensuring the symmetry and uniformity of the electric field distribution. This solves the problems of sample damage, uneven electric field distribution, and low monitoring accuracy of traditional methods. At the same time, the detachable elastic sealing cover and electrode plates can be reused.

[0015] The electrode sheet of this utility model is fixed by the conical positioning groove inside the detachable elastic sealing cover to ensure close contact between the electrode and the end face of the sample chamber; the lead hole on the detachable elastic sealing cover and the copper core are sealed with elastic seals to effectively prevent water leakage under preset pressure conditions. This design ensures the sealing performance of the electroosmosis test and the compatibility of NMR detection. Attached Figure Description

[0016] Figure 1 This is a schematic diagram showing the connection between the detachable elastic sealing cover and the sample chamber of this utility model;

[0017] Figure 2 This is an exploded view of the detachable elastic sealing cover and sample chamber of this utility model;

[0018] Figure 3 This is a schematic diagram of the overall structure of this utility model;

[0019] Figure 4(a) is a front view of the detachable elastic sealing cover of this utility model;

[0020] Figure 4(b) is a perspective view of the detachable elastic sealing cover of this utility model;

[0021] Figure 5 This is an overall test flowchart in the embodiments of this utility model;

[0022] In the figure: 1. Electrode sheet; 2. Copper core; 3. Sample chamber; 4. DC regulated power supply; 5. Removable elastic sealing cover; 5-1. Lead hole; 5-2. Conical positioning groove. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to specific embodiments. The description is for explanation and not limitation of the present invention.

[0024] like Figure 1 and 2 As shown, an electroosmotic experimental device for testing the porosity of concrete / mortar includes a sample chamber 3 for placing the test specimen. The sample chamber 3 is made of cylindrical PC material with an outer diameter of 60 mm and an inner diameter of 58 mm. Removable elastic sealing covers 5 are provided at both ends of the sample chamber 3. An electrode plate 1 is disposed between each removable elastic sealing cover 5 and the sample chamber 3. The electrode plate 1 is specifically a copper sheet with a diameter of 60 mm and a thickness of 2 mm. The two electrode plates 1 are arranged in parallel. A copper core 2 with a diameter of 1.5 mm and a length of 5 cm is welded perpendicularly to the center of the electrode plate 1. Figure 3 The removable elastic sealing cover 5 has a lead hole 5-1, and the two copper cores 2 pass through the lead hole 5-1 and are connected to the DC regulated power supply 4 through wires.

[0025] like Figure 4(a) and 4(b) As shown, the bottom of the detachable elastic sealing cover 5 is provided with a plurality of conical positioning grooves 5-2 for fixing the electrode sheet 1.

[0026] Furthermore, the lead hole 5-1 and the copper core 2 are sealed with an elastic seal.

[0027] An electroosmotic experimental device for testing the porosity of concrete / mortar includes a cylindrical sample chamber 3 containing concrete made of polycarbonate, a device for applying voltage during concrete electroosmosis, and a DC regulated power supply 4. The device for applying voltage during concrete electroosmosis includes a copper core 2 for applying voltage and an electrode plate 1 fixed inside a removable elastic sealing cover 5, which is nested within the sample chamber containing concrete. Each electrode plate has a copper core 2 with a diameter of 1.5 mm and a length of 5 cm welded to its outer side. The copper core 2 is connected to the DC power supply 4, and an electric field is applied to the experimental device through the copper core 2. The entire device can be placed into a nuclear magnetic resonance detection device after the electrode plates 1 are removed. The voltage change during the electroosmosis process is accurately measured through the nested voltage monitoring device to monitor the development of concrete electroosmosis. The nesting device uses a specially designed detachable elastic sealing cover 5 assembly. The detachable elastic sealing cover has an inner diameter of 62mm to ensure an interference fit with the end of the concrete sample chamber 1. A 1.5mm diameter lead hole 5-1 is specially opened in the center of the detachable elastic sealing cover 5 to ensure that the electric field application device is tightly connected to the detachable elastic sealing cover 5. The electric field application device, including the electrode plate 1 and the welded copper core 2, is fixed inside the detachable elastic sealing cover 5. The detachable elastic sealing cover assembly integrating the electric field application device is tightly fixed to the end of the concrete sample.

[0028] An experimental device for testing the porosity of concrete / mortar under an electric field based on nuclear magnetic resonance (NMR) technology, constructed using an electroosmotic experimental apparatus, is disclosed. The apparatus includes a sample preparation unit, an electroosmotic experimental device, and an NMR detection unit. The sample preparation unit prepares samples using dry mixing (140±5 r / min) and wet mixing (285±10 r / min) processes, and employs a vibrating table to ensure uniform porosity. The NMR detection unit uses a low-field NMR analyzer and sets a CPMG pulse sequence to monitor the T2 relaxation time distribution in real time. This experimental device for testing the porosity of concrete / mortar under an electric field based on NMR technology, constructed using the electroosmotic experimental apparatus of this invention, can not only simulate the actual water migration of concrete under electroosmotic demolding but also monitor the development of internal pores in the concrete. This overcomes the shortcomings of existing technologies, such as uneven electric field and low monitoring accuracy, and achieves efficient, non-destructive, and high-precision monitoring of water migration in cement mortar under an electric field.

[0029] The sample preparation unit includes a mixer, a sample chamber, and a vibrating table, used to prepare cement mortar samples according to the standard mix proportion. The mix proportion of the sample preparation unit strictly follows the specifications of GB 50010-2010 and JGJ 55-2011.

[0030] The nuclear magnetic resonance detection unit uses a MacroMR12-150H-I-60mm nuclear magnetic resonance analyzer with a magnetic field strength of 0.3T, a pulse sequence of CPMG, and an echo time of 0.1ms.

[0031] like Figure 5 As shown, a method for testing the porosity of concrete / mortar under the influence of an electric field based on nuclear magnetic resonance (NMR) technology, constructed using an electroosmotic experimental device of this invention, is described. After sample preparation, an electric field is applied. After the electroosmotic experiment, the electrodes, copper core, and power supply are removed, and the remaining components are assembled and placed into an NMR instrument for automatic detection. The data is used to analyze moisture migration patterns and support research on cement-based materials. The specific steps include:

[0032] Step 1: Weigh the materials according to the standard mix ratio, dry mix the sand at low speed for 30 seconds in the mixer, add the cement and mix at low speed for 60 seconds, then add water evenly and mix at high speed for 90 seconds. Fill the cement mortar into sample chamber 3 (cylindrical PC material, outer diameter 60mm, inner diameter 58mm), vibrate until the air bubbles disappear and the surface is flat, then seal it.

[0033] Step 2: Use 60mm diameter and 2mm thick copper sheets as anode and cathode. After cleaning the surface with sandpaper, arrange them parallel to each other at both ends of the sample chamber 3 to ensure tight symmetry. Weld copper core 2 to the center of electrode sheet 1 and fix it to the inside of the detachable elastic sealing cover 5. Copper core 2 passes through the lead hole of the cover. The cover is nested in the concrete sample chamber 3 by interference fit, so that electrode sheet 1 is in close contact with the specimen. Electrode sheet 1 is connected to DC regulated power supply 4 to apply an electric field for electroosmosis treatment. The detachable elastic sealing cover (62mm diameter PE material) has a copper core (1.5mm diameter copper rod) embedded in it to ensure interface electrical contact.

[0034] Step 3: After the electroosmosis test, first disconnect and remove the DC regulated power supply 4, remove the removable elastic sealing cover 5, take out the metal electrode plates 1 and copper core 2 at both ends, and ensure that there is no metal residue in the sample. Place the treated concrete sample directly into the sample chamber of the nuclear magnetic resonance equipment (using a MacroMR12-150H-I-60mm analyzer with a magnetic field strength of 0.3T), keeping its axis aligned with the magnetic field direction. Adjust the parameters of the nuclear magnetic resonance equipment for detection. Set the parameters including CPMG pulse sequence, echo time 0.1ms, and receiver gain 1-3, and obtain the transverse relaxation time T2 distribution curve. Calculate the porosity change and moisture spatial distribution data through inversion.

[0035] Step 4: After completing the test, remove the sample and analyze the influence of the electric field on the migration law of water inside the sample and the evolution of pore structure by comparing the experimental data before and after electroosmosis. During the electroosmosis process (0-180 min), the sample is placed in the analyzer every 15 minutes to monitor the T2 relaxation time distribution. The pore radius is calculated using the formula r = 20T2, and the water state is classified (gel water, capillary water, pore water, free water).

[0036] Although the present invention has been described through embodiments, parameters (such as voltage gradient or monitoring frequency) can be adjusted without departing from the scope of the claims to adapt to the testing requirements of different cement-based materials.

Claims

1. An electro-osmotic experimental device for concrete / mortar porosity testing, characterized by, The utility model relates to a test piece placing device, including the sample bin (3) for placing test piece, the both ends of sample bin (3) are provided with detachable elastic sealing cover (5), be provided with electrode sheet (1) between every detachable elastic sealing cover (5) and sample bin (3), two electrode sheets (1) are arranged in parallel, the copper core (2) is welded perpendicularly with electrode sheet (1) at the central position of electrode sheet (1), the detachable elastic sealing cover (5) is opened in lead hole (5-1), two copper cores (2) are connected with direct current stabilized power supply (4) through lead wire through lead hole (5-1) respectively.

2. The electro-osmotic experimental device for testing the porosity of concrete / mortar according to claim 1, characterized in that, The bottom of the detachable elastic sealing cover (5) is provided with a plurality of tapered positioning grooves (5-2) for fixing the electrode sheet (1).

3. The electro-osmotic experimental device for testing the porosity of concrete / mortar according to claim 1, characterized in that, The lead hole (5-1) and the copper core (2) are sealed with an elastic sealing member.

4. The electro-osmotic experimental device for testing the porosity of concrete / mortar according to claim 1, wherein, The electrode sheet (1) is specifically a red copper sheet, and the diameter of the electrode sheet (1) is 60 mm and the thickness is 2 mm.

5. The electro-osmotic experimental device for testing the porosity of concrete / mortar according to claim 1, wherein, The sample bin (3) is cylindrical, and the outer diameter is 60 mm and the inner diameter is 58 mm.

6. The electro-osmotic experimental device for testing the porosity of concrete / mortar according to claim 1, wherein, The inner diameter of the detachable elastic sealing cover (5) is 62 mm.

7. The electro-osmotic experimental device for testing the porosity of concrete / mortar according to claim 1, wherein, The sample bin (3) is made of PC material.

8. The electro-osmotic experimental device for testing the porosity of concrete / mortar according to claim 1, wherein, The diameter of the copper core (2) is 1.5 mm, and the length is 5 cm.

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