A device and method for testing the permeability of concrete

Abstract

This invention belongs to the field of concrete testing technology, specifically relating to a concrete permeability testing device and method. The device includes a main testing hole, several auxiliary testing holes, a sealing assembly, a vacuum degree measurement assembly, and a permeability calculation module. By adding auxiliary testing holes and using a physical model based on the pressure difference between the main and auxiliary holes, combined with a permeability calculation formula including the test volume parameter X, the invention calculates the concrete permeability. This formula directly converts the vacuum degree measurement result into a quantified concrete permeability K, solving the technical problem that the traditional Figg test method can only provide qualitative assessments and cannot provide specific permeability parameters, thus providing accurate data support for engineering evaluation.

Description

Technical Field

[0001] This invention belongs to the field of concrete testing technology, specifically relating to a concrete permeability testing device and method. Background Technology

[0002] As one of the most widely used structural materials in construction engineering, concrete's durability directly affects the safety, stability, and service life of building structures. The concrete surface layer is a key line of defense against the intrusion of corrosive substances such as chlorides, sulfates, and carbon dioxide. The intrusion process of these corrosive substances is closely related to the permeability of concrete; therefore, accurately testing concrete permeability is a core aspect of assessing its durability.

[0003] Currently, common methods for on-site assessment of concrete permeability include surface measurement and borehole transport measurement. The Figg test, a typical borehole transport measurement method, indirectly reflects the density and durability of concrete by measuring the gas permeation rate within the concrete, and has found some application in engineering practice. However, this test method has significant drawbacks: firstly, it cannot provide volume information of the tested concrete, making it difficult to accurately locate the permeation area; secondly, it can only achieve a qualitative assessment of permeability performance and cannot calculate quantitative concrete permeability parameters, thus limiting the practicality and reference value of the test results. Summary of the Invention

[0004] To address the aforementioned shortcomings of the prior art, the present invention provides a concrete permeability testing device and method.

[0005] In a first aspect, the present invention provides a concrete permeability testing device, comprising a main test hole, several auxiliary test holes, a sealing component, a vacuum degree measuring component, and a permeability calculation module. The main test hole is drilled into the surface of the concrete to be tested, and the auxiliary test holes are distributed around the main test hole. The sealing component is disposed within the main test hole and the auxiliary test holes. The vacuum degree measuring component is mounted on the sealing component and is connected to both the main test hole and the auxiliary test holes. The permeability calculation module is signal-connected to the vacuum degree measuring component and is used to receive vacuum degree measurement data and perform permeability calculation.

[0006] A further improvement to this technical solution is that the sealing assembly includes a silicone sealing plug, which is configured to fit tightly against the wall of the test auxiliary hole and the wall of the test main hole. The silicone sealing plug has an installation through hole that extends along the axial direction of the test auxiliary hole and the axial direction of the test main hole.

[0007] Further improvements to this technical solution include a vacuum measurement component comprising an injection needle and a piezoresistive pressure sensor. The injection needle is inserted into the mounting through-hole of the silicone sealing plug, with one end extending to the bottom of the test main hole or test auxiliary hole and the other end exposed on the concrete surface to be tested. The piezoresistive pressure sensor is fixedly mounted on the injection needle, and the sensing end of the piezoresistive pressure sensor is located inside the test main hole or test auxiliary hole.

[0008] Further improvements to this technical solution include: the injection needle and the silicone sealing plug are interference-fitted through the mounting hole, with no gap between the outer wall of the injection needle and the wall of the mounting hole; the piezoresistive pressure sensor is connected to the injection needle via a thread, and the housing of the piezoresistive pressure sensor abuts against the end face of the silicone sealing plug.

[0009] Further improvements to this technical solution include a permeability calculation module comprising a data receiving unit, a parameter storage unit, and a calculation unit. The data receiving unit is connected to a piezoresistive pressure sensor to receive pressure data; the parameter storage unit stores the fluid viscosity parameters of the concrete; and the calculation unit retrieves the pressure data received by the data receiving unit and the fluid viscosity parameters stored in the parameter storage unit to calculate the permeability of the concrete to be tested.

[0010] Secondly, the present invention provides a method for testing the permeability of concrete, applicable to the concrete permeability testing apparatus described in any of the above claims, the method comprising: S1. Drill test main holes and test auxiliary holes on the concrete surface to be tested; S2. Install sealing components in the main test hole and the auxiliary test hole to ensure that the sealing components fit tightly against the hole wall of the main test hole and the hole wall of the auxiliary test hole. S3. Install the injection needle and the piezoresistive pressure sensor on the sealing assembly, with the sensing end of the piezoresistive pressure sensor located inside the main test hole and the auxiliary test hole. S4. Zero the piezoresistive pressure sensor and record the calibration data. S5. Vacuum the test main hole by injection until the piezoresistive pressure sensor in the test auxiliary hole records a stable pressure. S6. Seal the main test hole, monitor and record the changes in the readings of the piezoresistive pressure sensors in the main test hole and the auxiliary test hole over time; S7. The permeability calculation module calculates the permeability of the concrete to be tested based on the pressure change data recorded in step S6.

[0011] Further improvements to this technical solution include the following specific method for zeroing the piezoresistive pressure sensor in step S4: Before using the injection needle to draw a vacuum, record the reading of the piezoresistive pressure sensor every preset time interval, and record it three times consecutively. If the difference between the three readings is less than the preset threshold, the piezoresistive pressure sensor is determined to be zeroed successfully. If the difference between any two readings is greater than or equal to the preset threshold, recalibrate until the zeroing requirement is met.

[0012] Further improvements to this technical solution include step S7, which includes: S71. Call the preset fluid viscosity E of the test concrete from the parameter storage unit in the permeability calculation module, calculate the radius r of the test main hole through the diameter of the test main hole, and record the actual distance d between the test main hole and the test auxiliary hole. S72. Extract the pressure P of the test main hole and the pressure P1 of the test auxiliary hole at different time points recorded in step S6 from the data receiving unit in the permeability calculation module. Combine them with atmospheric pressure Pa and substitute them into the first calculation formula in the calculation unit of the permeability calculation module. Calculate the auxiliary hole spacing X required for the pressure at the corresponding time point to recover to atmospheric pressure. S73. Substitute the calculated X value, the extracted P value, P1 value, the time t value after the start of the vacuum degree measurement process, and the preset E value, r value, and Pa value into the second calculation formula in the calculation unit of the permeability calculation module. Solve the equation to obtain the permeability K of the concrete to be tested. Take the average value of the K values ​​calculated at multiple time points as the final concrete permeability result.

[0013] Further improvements to this technical solution include the following: The first calculation formula is: .

[0014] A further improvement to this technical solution is that the second calculation formula is: .

[0015] The beneficial effects of this invention are as follows: This invention calculates the permeability of concrete by adding an auxiliary test hole and using a physical model based on the pressure difference between the main hole and the auxiliary hole, combined with a permeability calculation formula that includes the test volume parameter X. This formula can directly convert the vacuum degree measurement result into a quantified concrete permeability K, solving the technical problem that the traditional Figg test method can only provide qualitative assessments and cannot provide specific permeability parameters, thus providing accurate data support for engineering evaluation.

[0016] By introducing the parameter "the spacing X of the pores required for pressure to recover to atmospheric pressure," this invention automatically considers the effective volume of the test area in the calculation. This overcomes the deficiency of traditional methods in providing test volume information, enabling the test results to more accurately reflect the permeability characteristics of the concrete matrix and reducing the influence of boundary effects on the test results.

[0017] The system employs an interference fit between a silicone sealing plug and the injection needle, combined with a threaded connection between the piezoresistive pressure sensor and the injection needle, ensuring a high degree of sealing between the main test port and the auxiliary test port during vacuuming and pressure monitoring. This structural design effectively prevents air leakage, guarantees the stability of the vacuum level and the accuracy of pressure measurement data, thereby improving the reliability of the entire testing device and the repeatability of test results. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of a concrete permeability testing device.

[0020] Figure 2 This is a schematic diagram of the structure of the test main hole and the test auxiliary hole.

[0021] Figure 3 This is a schematic diagram of the sealing assembly.

[0022] Figure 4 This is a schematic flowchart illustrating a method according to an embodiment of the present invention.

[0023] 110 is the main test port, 120 is the auxiliary test port, 131 is the silicone sealing plug, 141 is the injection needle, and 142 is the piezoresistive pressure sensor. Detailed Implementation

[0024] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0026] like Figure 1 , Figure 2 and Figure 3 As shown, the present invention provides a concrete permeability testing device, including a main test hole 110, a plurality of auxiliary test holes 120, a sealing assembly, a vacuum degree measuring assembly, and a permeability calculation module. The main test hole 110 is drilled in the surface of the concrete to be tested, and the auxiliary test holes 120 are distributed around the main test hole 110. The sealing assembly is disposed in the main test hole 110 and the auxiliary test holes 120. The vacuum degree measuring assembly is installed on the sealing assembly and is connected to both the main test hole 110 and the auxiliary test holes 120. The permeability calculation module is signal-connected to the vacuum degree measuring assembly and is used to receive vacuum degree measurement data and perform permeability calculation.

[0027] The diameter of the test auxiliary hole 120 is 6 mm and the depth is 30 mm; the diameter of the test main hole 110 is 13 mm and the depth is 50 mm; the distance between the test auxiliary hole 120 and the test main hole 110 is 40 mm to ensure the stability and repeatability of the gas permeation path during the test.

[0028] Specifically, the sealing assembly includes a silicone sealing plug 131, which is tightly fitted to the wall of the test auxiliary hole 120 and the wall of the test main hole 110. The silicone sealing plug 131 has a mounting through hole extending along the axial direction of both the test auxiliary hole 120 and the test main hole 110. The silicone sealing plug 131 has a depth of 25 mm.

[0029] In use, the sealing component employs a silicone sealing plug 131. The silicone sealing plug 131 is made of highly elastic, aging-resistant medical-grade silicone, with a depth of 25mm, matching the depth of the main test hole 110 and the auxiliary test hole 120. During installation, the silicone sealing plug 131 is slowly pressed into the test hole, ensuring a tight fit between the outer wall of the silicone sealing plug 131 and the walls of the auxiliary test hole 120 and the main test hole 110, without any looseness or gaps, thus achieving initial sealing of the test hole. A mounting through hole is provided at the center of the silicone sealing plug 131, extending along the axial direction of the auxiliary test hole 120 and the main test hole 110, providing a channel for the installation of the vacuum measurement component.

[0030] In addition, the vacuum measurement component includes an injection needle 141 (specifically a vacuum injector) and a piezoresistive pressure sensor 142. The injection needle 141 is inserted into the mounting through hole of the silicone sealing plug 131. One end of the injection needle 141 extends to the bottom side of the test main hole 110 or test auxiliary hole 120, and the other end is exposed on the concrete surface to be tested. The piezoresistive pressure sensor 142 is fixedly installed on the injection needle 141, and the sensing end of the piezoresistive pressure sensor 142 is located in the test main hole 110 or test auxiliary hole 120.

[0031] The injection needle 141 and the silicone sealing plug 131 are interference-fitted through the mounting hole, and there is no gap between the outer wall of the injection needle 141 and the wall of the mounting hole; the piezoresistive pressure sensor 142 is connected to the injection needle 141 by a thread, and the outer shell of the piezoresistive pressure sensor 142 abuts against the end face of the silicone sealing plug 131.

[0032] The vacuum measurement assembly consists of an injection needle 141 and a piezoresistive pressure sensor 142. The injection needle 141 is made of stainless steel, providing excellent rigidity and sealing. Its outer diameter is matched to the inner diameter of the mounting hole of the silicone sealing plug 131, and it is inserted into the mounting hole using an interference fit to ensure no gap between the outer wall of the injection needle 141 and the wall of the mounting hole, preventing gas leakage. One end of the injection needle 141 extends to the bottom of the main test hole 110 or the auxiliary test hole 120, no more than 5 mm from the bottom of the hole, to accurately capture pressure changes within the hole; the other end protrudes from the concrete surface to be tested, for connecting the vacuum equipment and the sealing device. The piezoresistive pressure sensor 142 is a miniature sensor with an accuracy class of ±0.1% FS. It is fixedly installed on the injection needle 141 by a threaded connection. The sensing end of the piezoresistive pressure sensor 142 is completely located inside the test main hole 110 or the test auxiliary hole 120. Its shell is tightly abutted against the end face of the silicone sealing plug 131 to further enhance the sealing effect and ensure the timeliness of pressure sensing.

[0033] Use injection needle 141 to continuously evacuate the test main hole 110 to apply a constant vacuum until the pressure sensor of the test auxiliary hole 120 records a stable pressure. Seal the test main hole 110 and wait for the vacuum to decay, then measure the change in pressure sensor reading over time.

[0034] In use, the injection needle 141 is connected to a portable vacuum-pumping device to continuously pump air out of the main test hole 110, with the pumping rate controlled at 0.5L / min, until the fluctuation of the pressure value recorded by the piezoresistive pressure sensor 142 in the auxiliary test hole 120 for 30 consecutive seconds does not exceed ±0.01MPa, which is determined as a stable pressure state. Subsequently, the main test hole 110 is closed through the sealing valve matched with the injection needle 141 to enter the vacuum decay stage. In this process, the piezoresistive pressure sensor 142 synchronously records the pressure data in the main test hole 110 and the auxiliary test hole 120 at a frequency of 10s / time, and the continuous monitoring time is no less than 30min.

[0035] In addition, the permeability calculation module includes a data receiving unit, a parameter storage unit and a calculation unit. The data receiving unit is in signal connection with the piezoresistive pressure sensor 142 for receiving pressure data; the parameter storage unit is used for storing the fluid viscosity parameter of concrete; the calculation unit is used for calling the pressure data received by the data receiving unit and the fluid viscosity parameter stored in the parameter storage unit to calculate the permeability of the concrete to be tested.

[0036] In use, the permeability calculation module adopts an embedded control system, which includes a data receiving unit, a parameter storage unit and a calculation unit. The data receiving unit is in signal connection with the piezoresistive pressure sensor 142 through a wired communication interface, receives the digital signal transmitted by the pressure sensor in real time, and converts it into calculable pressure data; the parameter storage unit adopts a Flash memory, which pre-stores the fluid viscosity parameter E of different types of concrete (the fluid viscosity of ordinary concrete at normal temperature is preset to 1.81×10^-5 Pa s), and can update the parameters according to the actual type of tested concrete; the calculation unit adopts a microprocessor with ARM Cortex-M4 core, which has high-speed data processing capability, calls the pressure data received by the data receiving unit and the fluid viscosity parameter stored in the parameter storage unit, completes the automatic calculation of permeability through the pre-stored calculation formula, and outputs the final result.

[0037] The present invention clearly specifies the parameters of the diameter, depth and spacing of the main test hole 110 and the auxiliary hole, forming a standardized test layout, which avoids the deviation of test results caused by chaotic hole layout and inconsistent dimensions in traditional tests, enables the concrete permeability test data of different batches and different parts to be directly comparable, provides a unified benchmark for engineering quality assessment, and ensures the comparability and reliability of the test data.

[0038] The device employs a double-sealing design with an interference fit between the silicone sealing plug 131 and the injection needle 141. The high elasticity of the silicone sealing plug 131 allows it to tightly conform to the orifice wall, while the injection needle 141 fits seamlessly with the mounting through-hole. This effectively blocks gas exchange between the test orifice and the outside environment, completely solving the problems of poor sealing and easy vacuum leakage in traditional testing devices. The sealing structure provides excellent sealing performance, ensuring the stability of the testing environment. Simultaneously, the piezoresistive pressure sensor 142 abuts against the end face of the silicone sealing plug 131, further enhancing the sealing effect and ensuring the authenticity and accuracy of pressure data during vacuum decay.

[0039] The piezoresistive pressure sensor 142 features high precision and fast response. Its sensing end is placed directly inside the test port, enabling real-time capture of minute pressure changes. Data acquisition frequency reaches 10 seconds per acquisition, significantly improving the timeliness and accuracy of data acquisition compared to traditional pressure measurement devices. The rigid structure design of the injection needle 141 ensures smooth vacuuming, rapidly establishing a stable vacuum environment and shortening test preparation time.

[0040] The permeability calculation module integrates data reception, parameter storage, and automatic calculation functions, enabling the reception, processing, and calculation of pressure data without manual intervention. By pre-setting concrete fluid viscosity parameters and combining them with real-time collected pressure data, it can directly output quantitative permeability values, overcoming the limitation of the traditional Figg test method, which can only provide qualitative assessments. This provides accurate quantitative data support for concrete durability assessment, significantly improving the practicality and reference value of the test results.

[0041] Figure 4 This is a schematic flowchart illustrating a concrete permeability testing method provided by the present invention. Wherein, Figure 4 The instrument used for execution can be a concrete permeability testing device. Depending on the specific requirements, the order of the steps in this flowchart can be changed, and some steps can be omitted.

[0042] like Figure 4 As shown, the method includes: S1. Drill test main holes and test auxiliary holes on the concrete surface to be tested; S2. Install sealing components in the main test hole and the auxiliary test hole to ensure that the sealing components fit tightly against the hole wall of the main test hole and the hole wall of the auxiliary test hole. S3. Install the injection needle and the piezoresistive pressure sensor on the sealing assembly, with the sensing end of the piezoresistive pressure sensor located inside the main test hole and the auxiliary test hole. S4. Zero the piezoresistive pressure sensor and record the calibration data. S5. Vacuuming operation is performed on the main test hole by injection until the piezoresistive pressure sensor in the auxiliary test hole records a stable pressure. S6. Seal the main test hole, monitor and record the changes in the readings of the piezoresistive pressure sensors in the main test hole and the auxiliary test hole over time; S7. The permeability calculation module calculates the permeability of the concrete to be tested based on the pressure change data recorded in step S6.

[0043] To facilitate understanding of the present invention, the concrete permeability testing method provided by the present invention will be further described below, based on the principle of the concrete permeability testing method of the present invention and in conjunction with the process of conducting permeability testing on concrete in the embodiments.

[0044] Step S1: Drill the main test hole and the auxiliary test hole: Prepare the testing equipment, including a high-precision drilling machine (equipped with 6mm and 13mm diameter drill bits), silicone sealing plugs (25mm deep, with a central mounting hole), stainless steel injection needles, a piezoresistive pressure sensor with an accuracy of ±0.1% FS, a portable vacuum pump (adjustable pumping rate), a permeability calculation module (with built-in data receiving, parameter storage, and calculation units), and auxiliary tools such as an atmospheric pressure measuring instrument and a timer.

[0045] Step S2: Install the sealing assembly: Select silicone sealing plugs that match the test hole size, and slowly press them into the main test hole and each of the auxiliary test holes to a depth of 25mm. Ensure that the outer wall of the silicone sealing plug fits tightly against the hole wall without any looseness or gaps. After installation, gently pull the silicone sealing plug to check its secure fixation and prevent it from falling off or shifting during testing.

[0046] Step S3: Install the injection needle and piezoresistive pressure sensor: Stainless steel injection needles are inserted into the mounting holes of each silicone sealing plug, with an interference fit between the injection needle and the mounting hole to ensure no gaps between the outer wall of the injection needle and the hole wall. One end of the injection needle extends to the bottom of the main test hole or auxiliary test hole, approximately 3mm from the bottom; the other end protrudes from the concrete surface for connection to vacuum equipment or a sealing valve. Subsequently, a piezoresistive pressure sensor is fixedly mounted to the injection needle via a threaded connection, ensuring the sensing end of the piezoresistive pressure sensor is completely within the test hole, and the sensor housing is tightly abutted against the end face of the silicone sealing plug, further enhancing the sealing effect. After installation, a signal connection is established between the piezoresistive pressure sensor and the data receiving unit of the permeability calculation module.

[0047] Step S4: Zeroing and calibrating the piezoresistive pressure sensor: Specifically, the specific method for performing zero calibration on the piezoresistive pressure sensor in step S4 is: before using the injection needle to draw a vacuum, record the reading of the piezoresistive pressure sensor once every preset time, and record three times continuously. If the differences between the three readings are all less than the preset threshold, it is determined that the zeroing of the piezoresistive pressure sensor is successful; if the difference between any two readings is greater than or equal to the preset threshold, the calibration is re-performed until the zeroing requirement is met.

[0048] Before starting the vacuum pumping operation, perform zero calibration on all piezoresistive pressure sensors. The preset time is set to 10s, and the preset threshold is set to 0.005MPa. Record the reading of each pressure sensor once every 10s for three consecutive times. For example, the three recorded readings of a certain sensor are 0.001MPa, 0.002MPa, and 0.001MPa respectively, and the differences between the three readings are all less than 0.005MPa, then it is determined that the zeroing of this sensor is successful; if the three readings of a certain sensor are 0.001MPa, 0.007MPa, and 0.002MPa respectively, wherein the difference between the first two readings is 0.006MPa, which is greater than the preset threshold, it is necessary to check whether the sensor is installed firmly and whether the signal connection is normal, troubleshoot and then re-perform the calibration until all sensors meet the zeroing requirements, and store the calibration data in the permeability calculation module.

[0049] Step S5, vacuum pumping operation for the main test hole: Connect the portable vacuum pumping device to the injection needle corresponding to the main test hole, adjust the pumping rate to 0.5L / min, continuously pump air to the main test hole to apply a constant vacuum. During this process, monitor the reading changes of the piezoresistive pressure sensors in each auxiliary test hole in real time. When the readings of the pressure sensors in all auxiliary test holes remain stable for 30 consecutive seconds with a fluctuation range not exceeding ±0.01MPa, it is determined that a stable pressure state is reached, and the vacuum pumping operation is stopped.

[0050] Step S6, sealing the main test hole and monitoring pressure changes: Close the main test hole through the sealing valve matching the injection needle to realize the sealing of the main test hole. Subsequently, the data acquisition function of the permeability calculation module is started, and the piezoresistive pressure sensor synchronously records the pressure data in the main test hole and each auxiliary test hole at a frequency of once every 10s, with a continuous monitoring time of 30min, during which the pressure data is transmitted to the data receiving unit in real time and stored.

[0051] Wherein, step S7 includes: S71. Call the preset fluid viscosity E of the test concrete from the parameter storage unit in the permeability calculation module, calculate the radius r of the main test hole through the diameter of the main test hole, and record the actual distance d between the main test hole and the auxiliary test hole; S72. Extract the pressure P of the test main hole and the pressure P1 of the test auxiliary hole at different time points recorded in step S6 from the data receiving unit in the permeability calculation module. Combine them with atmospheric pressure Pa and substitute them into the first calculation formula in the calculation unit of the permeability calculation module. Calculate the auxiliary hole spacing X required for the pressure at the corresponding time point to recover to atmospheric pressure. S73. Substitute the calculated X value, the extracted P value, P1 value, the time t value after the start of the vacuum degree measurement process, and the preset E value, r value, and Pa value into the second calculation formula in the calculation unit of the permeability calculation module. Solve the equation to obtain the permeability K of the concrete to be tested. Take the average value of the K values ​​calculated at multiple time points as the final concrete permeability result.

[0052] Step S71, Parameter Calling and Confirmation: The preset test concrete fluid viscosity E is retrieved from the parameter storage unit of the permeability calculation module. If the test object is ordinary C30 concrete, the preset E value at room temperature is 1.81 × 10^-5 Pa. Based on the diameter of the main test hole (13mm), the radius of the main test hole (r) is calculated to be 6.5mm = 0.0065m. The actual distance between the main test hole and each auxiliary test hole (d) is confirmed to be 40mm = 0.04m through actual measurement, and the above parameters are recorded.

[0053] Furthermore, the first calculation formula is: .

[0054] Furthermore, the second calculation formula is: .

[0055] This invention breaks down the testing process into seven core steps, each with clearly defined operational requirements, parameter standards, and judgment criteria. For example, the size and spacing of the test holes, the time interval and threshold for sensor calibration, the vacuuming rate, and the pressure monitoring frequency are all clearly specified. This avoids the problem of arbitrary operation in traditional testing methods, ensuring consistency in the testing process for different operators and in different testing scenarios, and significantly reducing human error.

[0056] In step S4, the zeroing calibration method of "three consecutive readings verification" is adopted. By setting a reasonable time interval and difference threshold, it is ensured that the piezoresistive pressure sensor is in an accurate zeroing state at the initial stage of the test, avoiding pressure data measurement distortion caused by sensor zero drift, and providing a reliable original data basis for subsequent permeability calculation.

[0057] Step S7 employs a two-step calculation method of "first calculating X, then calculating K," combined with proprietary first and second calculation formulas. This method fully considers key factors such as atmospheric pressure, concrete fluid viscosity, test hole size, pressure variation, and time, constructing a complete parameter derivation chain. Furthermore, by selecting data from multiple time points for calculation and taking the average, the method effectively offsets the random errors of data from a single time point. This ensures that the final permeability K value accurately reflects the actual permeability performance of concrete, solving the technical challenge of the traditional Figg test method's inability to quantify permeability parameters.

[0058] Throughout the entire testing process, the acquisition, transmission, and storage of pressure data are all completed automatically by the permeability calculation module, eliminating the need for manual real-time recording. The permeability calculation is also automatically executed by the calculation unit according to the preset formula, which greatly reduces the manual intervention steps, not only reducing labor intensity but also avoiding errors that may occur in manual calculation, significantly improving testing efficiency, and making it suitable for large-scale, multi-batch concrete permeability testing scenarios.

[0059] The testing method of this invention does not rely on complex large-scale equipment, and the operation process is simple and easy to understand. It can be flexibly applied to on-site testing of different types of concrete projects, such as cast-in-place concrete structures and precast concrete components. At the same time, by adjusting the preset concrete fluid viscosity parameters, it can be adapted to the permeability testing of concretes with different strength grades and mix proportions, possessing strong practicality and promotional value.

[0060] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should also be covered within the protection scope of the present invention.

Claims

1. A concrete permeability testing device, characterized in that, The test includes a main test hole (110), several auxiliary test holes (120), a sealing assembly, a vacuum degree measurement assembly, and a permeability calculation module. The main test hole (110) is drilled on the surface of the concrete to be tested, and the auxiliary test holes (120) are distributed around the main test hole (110). The sealing assembly is set inside the main test hole (110) and the auxiliary test holes (120). The vacuum degree measurement assembly is installed on the sealing assembly and is connected to both the main test hole (110) and the auxiliary test holes (120). The permeability calculation module is signal-connected to the vacuum degree measurement assembly and is used to receive vacuum degree measurement data and complete permeability calculation.

2. The concrete permeability testing device according to claim 1, characterized in that, The sealing assembly includes a silicone sealing plug (131), which is fitted tightly against the wall of the test auxiliary hole (120) and the wall of the test main hole (110). The silicone sealing plug (131) has an installation through hole that extends along the axial direction of the test auxiliary hole (120) and the axial direction of the test main hole (110).

3. The concrete permeability testing device according to claim 2, characterized in that, The vacuum measurement assembly includes an injection needle (141) and a piezoresistive pressure sensor (142). The injection needle (141) is inserted into the mounting through hole of the silicone sealing plug (131). One end of the injection needle (141) extends to the bottom side of the test main hole (110) or test auxiliary hole (120), and the other end is exposed on the concrete surface to be tested. The piezoresistive pressure sensor (142) is fixedly installed on the injection needle (141), and the sensing end of the piezoresistive pressure sensor (142) is located in the test main hole (110) or test auxiliary hole (120).

4. The concrete permeability testing device according to claim 3, characterized in that, The injection needle (141) and the silicone sealing plug (131) are interference-fitted through the mounting hole, and there is no gap between the outer wall of the injection needle (141) and the hole wall of the mounting hole; the piezoresistive pressure sensor (142) is connected to the injection needle (141) by a thread, and the outer shell of the piezoresistive pressure sensor (142) abuts against the end face of the silicone sealing plug (131).

5. The concrete permeability testing device according to claim 3, characterized in that, The permeability calculation module includes a data receiving unit, a parameter storage unit, and a calculation unit. The data receiving unit is connected to a piezoresistive pressure sensor (142) to receive pressure data. The parameter storage unit is used to store the fluid viscosity parameters of the concrete. The calculation unit is used to call the pressure data received by the data receiving unit and the fluid viscosity parameters stored in the parameter storage unit to calculate the permeability of the concrete to be tested.

6. A method for testing the permeability of concrete, characterized in that, The method applicable to the concrete permeability testing apparatus according to any one of claims 1-5 includes: S1. Drill test main holes and test auxiliary holes on the concrete surface to be tested; S2. Install sealing components in the main test hole and the auxiliary test hole to ensure that the sealing components fit tightly against the hole wall of the main test hole and the hole wall of the auxiliary test hole. S3. Install the injection needle and the piezoresistive pressure sensor on the sealing assembly, with the sensing end of the piezoresistive pressure sensor located inside the main test hole and the auxiliary test hole. S4. Zero the piezoresistive pressure sensor and record the calibration data. S5. Vacuum the test main hole by injection until the piezoresistive pressure sensor in the test auxiliary hole records a stable pressure. S6. Seal the main test hole, monitor and record the changes in the readings of the piezoresistive pressure sensors in the main test hole and the auxiliary test hole over time; S7. The permeability calculation module calculates the permeability of the concrete to be tested based on the pressure change data recorded in step S6.

7. The concrete permeability testing method according to claim 6, characterized in that, The specific method for zeroing the piezoresistive pressure sensor in step S4 is as follows: Before using the injection needle to draw a vacuum, record the reading of the piezoresistive pressure sensor every preset time interval, and record it three times in a row. If the difference between the three readings is less than the preset threshold, the piezoresistive pressure sensor is determined to be zeroed successfully. If the difference between any two readings is greater than or equal to the preset threshold, recalibrate until the zeroing requirement is met.

8. The concrete permeability testing method according to claim 6, characterized in that, Step S7 includes: S71. Call the preset fluid viscosity E of the test concrete from the parameter storage unit in the permeability calculation module, calculate the radius r of the test main hole through the diameter of the test main hole, and record the actual distance d between the test main hole and the test auxiliary hole. S72. Extract the pressure P of the test main hole and the pressure P1 of the test auxiliary hole at different time points recorded in step S6 from the data receiving unit in the permeability calculation module. Combine them with atmospheric pressure Pa and substitute them into the first calculation formula in the calculation unit of the permeability calculation module. Calculate the auxiliary hole spacing X required for the pressure at the corresponding time point to recover to atmospheric pressure. S73. Substitute the calculated X value, the extracted P value, P1 value, the time t value after the start of the vacuum degree measurement process, and the preset E value, r value, and Pa value into the second calculation formula in the calculation unit of the permeability calculation module. Solve the equation to obtain the permeability K of the concrete to be tested. Take the average value of the K values ​​calculated at multiple time points as the final concrete permeability result.

9. The concrete permeability testing method according to claim 8, characterized in that, The first calculation formula is: 。 10. The concrete permeability testing method according to claim 8, characterized in that, The second calculation formula is: 。

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