A low-field nuclear magnetic resonance testing device and method for permeability resistance of loaded concrete

Abstract

This invention relates to a low-field nuclear magnetic resonance (NMR) testing device and method for assessing the impermeability of loaded concrete. The device includes: a sample assembly mechanism comprising a sample chamber and a first and second support installed within the sample chamber with adjustable spacing, wherein a concrete sample is placed between the first and second supports; a low-field NMR mechanism comprising a coil, a magnet, a radio frequency oscillator, an amplifier, a detector, and a controller; an impermeability pressurization mechanism comprising an impermeable water channel and a constant-pressure water injection assembly connected to the impermeable water channel; and a test load loading mechanism comprising a deformation testing element, a support drive assembly, and a load acquisition module. Compared with existing technologies, this invention, combining low-field NMR technology, is non-destructive and rapid on concrete materials, eliminating the need for splitting the impermeable concrete, and enabling rapid and non-destructive detection of moisture changes during concrete impermeability testing.

Description

Technical Field

[0001] This invention belongs to the field of concrete impermeability testing technology for building materials, and relates to a low-field nuclear magnetic resonance testing device and method for the impermeability of loaded concrete. Background Technology

[0002] The "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete" (GB / T 50082-2009) includes two water permeability tests: the step-by-step pressure method and the permeability height method. These two methods are cumbersome, labor-intensive, and time-consuming, and are prone to leaks due to sealing problems, requiring rework. Furthermore, the permeability grade of concrete cannot be directly used for permeability calculations in concrete structural design; they are not suitable for high-performance concrete with high permeability; and they differ from the actual conditions of concrete structures, as no load is applied during the test, and measuring the permeability height by breaking the specimen after the test is relatively time-consuming.

[0003] The ion permeability evaluation method based on the effect of electric field shows a discrepancy between the results of the electric flux method and the actual Cl- permeability. This is mainly because the 60V test voltage causes polarization in the concrete, generating heat inside and affecting the test results; other ions in the concrete solution also contribute to the total charge; and it is difficult to achieve Cl- diffusion stability within the test time. The vacuum saturation process in the conductivity method cannot ensure that the NaCl solution is completely and uniformly distributed inside the concrete specimen, and the NEL method requires drying the specimen, which may form microcracks inside the concrete, reducing its impermeability. The unsteady-state electromigration method (RCM method): after applying a 30V DC voltage, the Cl- concentration in the concrete changes not only with location but also with time.

[0004] Gas permeation test method. This method involves exposing one end of the test specimen to atmospheric pressure while applying a constant pressure (0.15 MPa, 0.20 MPa, 0.30 MPa) of gas to the other end, ensuring a constant gas flow rate within the specimen. The gas flow rate is measured after 30 minutes, and the permeation coefficient is then calculated. This method has a long specimen preparation time and a complex testing procedure. Summary of the Invention

[0005] The purpose of this invention is to provide a low-field nuclear magnetic resonance testing device and method for evaluating the impermeability of loaded concrete, which can accurately and quickly obtain the data required to evaluate the impermeability of concrete materials, thereby realizing a non-destructive and rapid evaluation of the impermeability of concrete materials.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] One of the technical solutions of the present invention provides a low-field nuclear magnetic resonance testing device for the impermeability of loaded concrete, comprising:

[0008] The sample assembly mechanism includes a sample chamber and a first support and a second support installed in the sample chamber. The distance between the first support and the second support is adjustable. The concrete sample to be tested is placed between the first support and the second support.

[0009] A low-field nuclear magnetic resonance apparatus includes a coil arranged around the concrete sample being tested, a magnet arranged symmetrically about the concrete sample being tested, a radio frequency oscillator, an amplifier, a detector, and a controller, wherein the controller is connected in sequence to the radio frequency oscillator and the coil, and the coil is also connected in sequence to the amplifier, the detector, and the controller.

[0010] An anti-seepage pressurization mechanism includes an anti-seepage channel machined on the second support and extending to contact the surface of the concrete sample to be tested, and a constant pressure water injection component connected to the anti-seepage channel and used to inject constant pressure water into the anti-seepage channel.

[0011] The test load loading mechanism includes a deformation testing element, a support driving assembly, and a load acquisition module. The deformation testing element is disposed on the surface of the concrete sample to be tested and is used to test the deformation of the concrete sample under load. The support driving assembly is connected to a first support and is used to drive the first support to move to adjust the test load on the concrete sample to be tested. The load acquisition module is connected to the support driving assembly and is used to test the test load data of the concrete sample to be tested via the support driving assembly.

[0012] Furthermore, the sample chamber is also machined with internal threads, and the first support and the second support are respectively threaded to the inner wall of the sample chamber.

[0013] Furthermore, a third support is fixedly provided at the end of the sample chamber near the first support, and the two ends of the load acquisition module are respectively connected to the third support and the support drive assembly.

[0014] Furthermore, the portion of the second support that contacts the concrete sample being tested is also equipped with a water-stopping structure.

[0015] Furthermore, the load acquisition module is a displacement sensing module that acquires the displacement of the first support.

[0016] Furthermore, both the load acquisition module and the deformation testing element are connected to the AD conversion module, which is also connected to the controller.

[0017] Furthermore, the signal input terminal of the radio frequency oscillator is connected to the first signal output terminal of the controller; the constant pressure water injection assembly is also provided with a constant pressure water injection module for controlling its operation, and the signal input terminal of the constant pressure water injection module is connected to the second signal output terminal of the controller; the support drive assembly is also provided with a support drive module for controlling its operation, and the signal input terminal of the support drive module is also connected to the third signal output terminal of the controller.

[0018] Furthermore, the first signal input terminal of the controller is also connected to the signal output terminal of the detector, and the second signal input terminal of the controller is also connected to the signal output terminal of the AD conversion module.

[0019] The second technical solution of the present invention provides a low-field nuclear magnetic resonance testing method for the impermeability of loaded concrete, which is based on the low-field nuclear magnetic resonance testing device described above, and the method includes the following steps:

[0020] (1) Install the concrete sample to be tested between the first support and the second support and clamp it in place;

[0021] (2) Start the test load loading mechanism. The deformation test element and load acquisition module collect the deformation and test load of the concrete sample in real time, and then output the data to the AD conversion module. The controller performs data analysis and storage.

[0022] (3) Control the operation of the constant pressure water injection component to stabilize the anti-seepage pressure in the anti-seepage channel at the set value of the controller;

[0023] (4) The frequency of the incident electromagnetic wave of the radio frequency oscillator is adjusted by the controller according to the preset time interval, and the energy data absorbed by the detector from the amplifier is recorded.

[0024] Furthermore, when the deformation testing element and the load acquisition module output a low level, it is determined that the deformation and compression of the tested concrete sample are consistent with the target set value of the controller. Otherwise, the support drive component is controlled to run and the load on the tested concrete sample is adjusted until the target value is reached.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] 1) A rapid and non-destructive evaluation method for the impermeability transmission performance of concrete under different water pressures was realized based on low-field nuclear magnetic resonance testing;

[0027] 2) It can simulate the real-time testing of water transport performance of concrete in a loaded environment to determine the contribution of different pore sizes to the concrete's impermeability. Attached Figure Description

[0028] Figure 1This is a schematic diagram of the structure of the present invention;

[0029] Explanation of markings in the diagram:

[0030] 10-Controller, 11-RF oscillator, 12-Coil, 13-Amplifier, 14-Detector, 15-Magnet;

[0031] 21-Constant pressure water injection module, 22-Constant pressure water supply component, 23-Imperceptible water channel;

[0032] 31-Support drive module, 32-Support drive assembly, 33-AD conversion module, 34-Deformation test element, 35-Load acquisition module;

[0033] 41-Sample chamber, 42-First support, 43-Second support, 44-Third support. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0035] Unless otherwise specified, the functional components or structures in the following embodiments or examples are conventional components or structures used in the art to achieve the corresponding functions.

[0036] To enable rapid, non-destructive testing of moisture changes during concrete impermeability testing, this invention provides a low-field nuclear magnetic resonance (NMR) testing device for the impermeability of loaded concrete, the structure of which can be found in [reference needed]. Figure 1 As shown, it includes:

[0037] The sample assembly mechanism includes a sample chamber 41 and a first support 42 and a second support 43 installed in the sample chamber 41. The distance between the first support 42 and the second support 43 is adjustable. The concrete sample to be tested is placed between the first support 42 and the second support 43.

[0038] The low-field nuclear magnetic resonance apparatus includes a coil 12 arranged around the concrete sample to be tested, a magnet 15 arranged symmetrically with the concrete sample to be tested as the center, a radio frequency oscillator 11, an amplifier 13, a detector 14 and a controller 10, wherein the controller 10 is connected in sequence to the radio frequency oscillator 11 and the coil 12, and the coil 12 is also connected in sequence to the amplifier 13, the detector 14 and the controller 10.

[0039] The anti-seepage pressurization mechanism includes an anti-seepage channel 23 machined on the second support 43 and extending to contact the surface of the concrete sample to be tested, and a constant pressure water injection component connected to the anti-seepage channel 23 and used to inject constant pressure water into the anti-seepage channel 23.

[0040] The test load loading mechanism includes a deformation testing element 34, a support drive assembly 32, and a load acquisition module 35. The deformation testing element 34 is disposed on the surface of the concrete sample to be tested and is used to test the deformation of the concrete sample under load. The support drive assembly 32 is connected to the first support 42 and is used to drive the first support 42 to move to adjust the test load on the concrete sample to be tested. The load acquisition module 35 is connected to the support drive assembly 32 and is used to test the test load data of the concrete sample to be tested through the support drive assembly 32.

[0041] In some specific embodiments, the sample chamber 41 is further machined with internal threads, and the first support 42 and the second support 43 are respectively threadedly fixed to the inner wall of the sample chamber 41. Additionally, the sample chamber 41 is preferably cylindrical. In this case, the support drive assembly 32 is preferably a conventional drive mechanism capable of driving the first support 42 to rotate.

[0042] In some specific embodiments, a third support 44 is fixedly provided on the sample chamber 41 near the end of the first support 42, and the two ends of the load acquisition module 35 are respectively connected to the third support 44 and the support drive assembly 32. The load acquisition module 35 can be a displacement sensor module or the like that that collects the displacement of the support drive assembly 32. In this case, the load on the concrete sample under test is characterized by the collected displacement.

[0043] In some specific embodiments, the portion of the second support 43 that contacts the concrete sample being tested is also provided with a water-stopping structure. Through the water-stopping structure, it can be ensured that the contact portion between the second support 43 surrounding the anti-seepage channel 23 and the concrete sample being tested is in sealed contact.

[0044] In some specific implementations, the load acquisition module 35 is a displacement sensing module that acquires the displacement of the first support 42.

[0045] In some specific embodiments, the load acquisition module 35 and the deformation testing element 34 are also connected to the AD conversion module 33, which is also connected to the controller 10.

[0046] In a more specific embodiment, the signal input terminal of the radio frequency oscillator 11 is connected to the first signal output terminal of the controller 10; the constant pressure water injection assembly is further provided with a constant pressure water injection module 21 for controlling its operation, and the signal input terminal of the constant pressure water injection module 21 is connected to the second signal output terminal of the controller 10; the support drive assembly 32 is further provided with a support drive module 31 for controlling its operation, and the signal input terminal of the support drive module 31 is also connected to the third signal output terminal of the controller 10. The constant pressure water injection module 21 and the support drive module 31 are control modules for controlling the operation of the constant pressure water injection assembly and the support drive assembly 32, respectively, and they can also be integrated into the controller 10.

[0047] In a more specific embodiment, the first signal input terminal of the controller 10 is also connected to the signal output terminal of the detector 14, and the second signal input terminal of the controller 10 is also connected to the signal output terminal of the AD conversion module 33.

[0048] Furthermore, the controller 10, radio frequency oscillator 11, amplifier 13, detector 14, constant pressure water supply assembly 22, and other functional components or modules in this invention are not protected points of this invention, and the components used are all conventionally known components in the art.

[0049] Each of the above implementation methods can be implemented individually, or in any combination of two or more.

[0050] The above implementation methods will be described in more detail below with reference to specific embodiments.

[0051] Example 1:

[0052] To enable rapid, non-destructive testing of moisture changes during concrete impermeability testing, this invention provides a low-field nuclear magnetic resonance (NMR) testing device for the impermeability of loaded concrete, the structure of which can be found in [reference needed]. Figure 1 As shown, it includes:

[0053] The sample assembly mechanism includes a sample chamber 41 and a first support 42 and a second support 43 installed in the sample chamber 41. The distance between the first support 42 and the second support 43 is adjustable. The concrete sample to be tested is placed between the first support 42 and the second support 43.

[0054] The low-field nuclear magnetic resonance apparatus includes a coil 12 arranged around the concrete sample to be tested, a magnet 15 arranged symmetrically with the concrete sample to be tested as the center, a radio frequency oscillator 11, an amplifier 13, a detector 14 and a controller 10, wherein the controller 10 is connected in sequence to the radio frequency oscillator 11 and the coil 12, and the coil 12 is also connected in sequence to the amplifier 13, the detector 14 and the controller 10.

[0055] The anti-seepage pressurization mechanism includes an anti-seepage channel 23 machined on the second support 43 and extending to contact the surface of the concrete sample to be tested, and a constant pressure water injection component connected to the anti-seepage channel 23 and used to inject constant pressure water into the anti-seepage channel 23.

[0056] The test load loading mechanism includes a deformation testing element 34, a support drive assembly 32, and a load acquisition module 35. The deformation testing element 34 is disposed on the surface of the concrete sample to be tested and is used to test the deformation of the concrete sample under load. The support drive assembly 32 is connected to the first support 42 and is used to drive the first support 42 to move to adjust the test load on the concrete sample to be tested. The load acquisition module 35 is connected to the support drive assembly 32 and is used to test the test load data of the concrete sample to be tested through the support drive assembly 32.

[0057] The sample chamber 41 is also machined with internal threads, and the first support 42 and the second support 43 are respectively threadedly fixed to the inner wall of the sample chamber 41. Alternatively, the sample chamber 41 can preferably be in the shape of a cylindrical sleeve. In this case, the support drive assembly 32 is preferably a conventional drive mechanism capable of driving the first support 42 to rotate.

[0058] A third support 44 is fixedly installed on the sample chamber 41 near the end of the first support 42. The two ends of the load acquisition module 35 are respectively connected to the third support 44 and the support drive assembly 32. The load acquisition module 35 can be a displacement sensor module or the like that that collects the displacement of the support drive assembly 32. In this case, the load on the concrete sample under test is characterized by the collected displacement.

[0059] The portion of the second support 43 that contacts the concrete sample being tested is also provided with a water-stopping structure. Through the water-stopping structure, it can be ensured that the contact portion between the second support 43 surrounding the anti-seepage channel 23 and the concrete sample being tested is in sealed contact.

[0060] The load acquisition module 35 is a displacement sensing module that acquires the displacement of the first support 42.

[0061] The load acquisition module 35 and the deformation testing element 34 are both connected to the AD conversion module 33, which is also connected to the controller 10.

[0062] The signal input terminal of the radio frequency oscillator 11 is connected to the first signal output terminal of the controller 10; the constant pressure water injection assembly is also provided with a constant pressure water injection module 21 for controlling its operation, and the signal input terminal of the constant pressure water injection module 21 is connected to the second signal output terminal of the controller 10; the support drive assembly 32 is also provided with a support drive module 31 for controlling its operation, and the signal input terminal of the support drive module 31 is also connected to the third signal output terminal of the controller 10. The constant pressure water injection module 21 and the support drive module 31 are control modules for controlling the operation of the constant pressure water injection assembly and the support drive assembly 32, respectively, and they can also be integrated into the controller 10. The first signal input terminal of the controller 10 is also connected to the signal output terminal of the detector 14, and the second signal input terminal of the controller 10 is also connected to the signal output terminal of the AD conversion module 33.

[0063] The workflow of this invention is as follows:

[0064] 1) Install the concrete sample to be tested between the first support 42 and the second support 43 and clamp and fix it;

[0065] 2) Start the test load loading mechanism. The deformation test element 34 and the load acquisition module 35 collect the deformation and test load of the concrete sample in real time and feed them back to the AD conversion module 33. The controller 10 then analyzes and stores the data. When the deformation test element 34 and the load acquisition module 35 output a low level, it is determined that the deformation and compression of the concrete sample are consistent with the target set value of the controller 10. Otherwise, the support drive assembly 32 is controlled to run and the load on the concrete sample is adjusted until the target value is reached.

[0066] 3) Control the operation of the constant pressure water injection component to stabilize the anti-seepage pressure in the anti-seepage channel 23 at the set value of the controller 10;

[0067] 4) The frequency of the incident electromagnetic wave of the radio frequency oscillator 11 is adjusted by the controller 10 according to the preset time interval and scanned. When the radiation frequency matches the magnetic field strength H0 generated by the magnet 15, nuclear magnetic resonance occurs and the energy data absorbed by the detector 14 from the amplifier 13 is recorded.

[0068] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A low-field nuclear magnetic resonance testing device for the impermeability of loaded concrete, characterized in that, include: The sample assembly mechanism includes a sample chamber and a first support and a second support installed in the sample chamber. The distance between the first support and the second support is adjustable. The concrete sample to be tested is placed between the first support and the second support. A low-field nuclear magnetic resonance apparatus includes a coil arranged around the concrete sample being tested, a magnet arranged symmetrically about the concrete sample being tested, a radio frequency oscillator, an amplifier, a detector, and a controller, wherein the controller is connected in sequence to the radio frequency oscillator and the coil, and the coil is also connected in sequence to the amplifier, the detector, and the controller. An anti-seepage pressurization mechanism includes an anti-seepage channel machined on the second support and extending to contact the surface of the concrete sample to be tested, and a constant pressure water injection component connected to the anti-seepage channel and used to inject constant pressure water into the anti-seepage channel. The test load loading mechanism includes a deformation testing element, a support driving assembly, and a load acquisition module. The deformation testing element is disposed on the surface of the concrete sample to be tested and is used to test the deformation of the concrete sample under load. The support driving assembly is connected to a first support and is used to drive the first support to move to adjust the test load on the concrete sample to be tested. The load acquisition module is connected to the support driving assembly and is used to test the test load data of the concrete sample to be tested via the support driving assembly.

2. The low-field nuclear magnetic resonance testing device for the impermeability of loaded concrete according to claim 1, characterized in that, The sample chamber is also machined with internal threads, and the first support and the second support are respectively threaded to the inner wall of the sample chamber.

3. The low-field nuclear magnetic resonance testing device for the impermeability of loaded concrete according to claim 1, characterized in that, A third support is fixedly provided at the end of the sample chamber near the first support, and the two ends of the load acquisition module are respectively connected to the third support and the support drive assembly.

4. The low-field nuclear magnetic resonance testing device for the impermeability of loaded concrete according to claim 1, characterized in that, The portion of the second support that contacts the concrete sample being tested is also equipped with a water-stopping structure.

5. A low-field nuclear magnetic resonance testing device for the impermeability of loaded concrete according to claim 1, characterized in that, The load acquisition module is a displacement sensing module that acquires the displacement of the first support.

6. The low-field nuclear magnetic resonance testing device for the impermeability of loaded concrete according to claim 1, characterized in that, Both the load acquisition module and the deformation testing element are connected to the AD conversion module, which is also connected to the controller.

7. A low-field nuclear magnetic resonance testing device for the impermeability of loaded concrete according to claim 6, characterized in that, The signal input terminal of the radio frequency oscillator is connected to the first signal output terminal of the controller; the constant pressure water injection assembly is also provided with a constant pressure water injection module for controlling its operation, and the signal input terminal of the constant pressure water injection module is connected to the second signal output terminal of the controller; the support drive assembly is also provided with a support drive module for controlling its operation, and the signal input terminal of the support drive module is also connected to the third signal output terminal of the controller.

8. A low-field nuclear magnetic resonance testing device for the impermeability of loaded concrete according to claim 6, characterized in that, The first signal input terminal of the controller is also connected to the signal output terminal of the detector, and the second signal input terminal of the controller is also connected to the signal output terminal of the AD conversion module.

9. A low-field nuclear magnetic resonance (NMR) testing method for the impermeability of loaded concrete, based on the low-field NMR testing apparatus as described in any one of claims 1-8, characterized in that, The method includes the following steps: (1) Install the concrete sample to be tested between the first support and the second support and clamp it in place; (2) Start the test load loading mechanism. The deformation test element and load acquisition module collect the deformation and test load of the concrete sample in real time, and then output the data to the AD conversion module. The controller performs data analysis and storage. (3) Control the operation of the constant pressure water injection component to stabilize the anti-seepage pressure in the anti-seepage channel at the set value of the controller; (4) The frequency of the incident electromagnetic wave of the radio frequency oscillator is adjusted by the controller according to the preset time interval, and the energy data absorbed by the detector from the amplifier is recorded.

10. A low-field nuclear magnetic resonance testing method for the impermeability of loaded concrete according to claim 9, characterized in that, When the deformation testing element and the load acquisition module output a low level, it is determined that the deformation and compression of the tested concrete sample are consistent with the target set value of the controller. Otherwise, the support drive component is controlled to run and the load on the tested concrete sample is adjusted until the target value is reached.

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