Method and system for testing durability of sprayed concrete

Abstract

The invention provides a method and system for testing durability of sprayed concrete, and relates to the technical field of concrete test.The method comprises the steps that extreme environment configuration is conducted within a preset application environment range, and a target testing environment is generated; concrete durability loss analysis is carried out based on a preset spraying process, and durability loss constraints are constructed; based on the target test environment and the durability loss constraint, performing an indoor forming test on the to-be-tested sprayed concrete through an indoor forming test piece tool, and adjusting the surface flatness to obtain a test sample; and carrying out durability test and durability prediction on the test sample to generate a durability test result. The technical problem that in the prior art, due to the fact that durability loss of sprayed concrete in the construction process and the comprehensive influence of the actual application environment are not fully considered, deviation exists between the testing result and actual engineering application is solved, and the technical effect of improving durability testing accuracy and engineering applicability is achieved.

Description

Technical Field

[0001] This application relates to the technical field of concrete testing, and specifically to a method and system for testing the durability performance of shotcrete. Background Art

[0002] Shotcrete is widely used in engineering fields such as tunnel lining, slope protection, and mine support. Its durability performance is crucial for the safety and long-term serviceability of structures.

[0003] Currently, the durability performance testing of shotcrete mainly relies on the laboratory environment. By preparing specimens and conducting tests such as compressive strength, freeze-thaw resistance, and impermeability, its long-term durability is predicted. However, there are still certain limitations in this traditional testing method. Firstly, the existing testing methods are usually based on standard laboratory conditions and do not fully consider the environmental factors during the actual shotcrete construction, such as extreme conditions like temperature and humidity changes, chemical erosion, and freeze-thaw cycles, resulting in a mismatch between the test results and the actual working conditions. Secondly, the existing methods mainly focus on the durability after the concrete hardens and do not fully consider the durability performance loss caused by factors such as material segregation and rebound loss during the pumping, spraying, and transportation processes of the concrete, leading to higher experimental data and affecting the reliability of engineering design. Summary of the Invention

[0004] This application provides a method and system for testing the durability performance of shotcrete, which solves the technical problem that the existing technology has a deviation between the test results and the actual engineering application due to insufficient consideration of the durability performance loss and the comprehensive influence of the actual application environment during the construction process of shotcrete, and achieves the technical effect of improving the accuracy of the durability performance testing and the engineering applicability of shotcrete.

[0005] In view of the above problems, on the one hand, this application provides a method for testing the durability performance of shotcrete. The method includes: reading the preset spraying process and preset application environment of the shotcrete to be tested; configuring an extreme environment within the range of the preset application environment to generate a target test environment; analyzing the durability performance loss of the concrete based on the preset spraying process to construct a durability performance loss constraint; controlling the indoor environment with the target test environment and synchronously adjusting the durability performance loss with the durability performance loss constraint, and conducting an indoor forming test on the shotcrete to be tested through an indoor forming specimen tooling. After forming, perform surface flatness adjustment to obtain a test sample; conduct durability performance testing on the test sample and establish a durability life estimation model for durability life prediction to generate durability performance test results.

[0006] Preferably, based on the preset spraying process, an analysis of the durability performance loss of concrete is carried out to construct a durability performance loss constraint, including: analyzing the preset spraying process to establish multiple spraying process nodes; extracting a first spraying node and a second spraying node from the multiple spraying process nodes, wherein the first spraying node and the second spraying node are two sequentially connected nodes; carrying out an analysis of the durability performance loss on the concrete flow path between the first spraying node and the second spraying node to generate the durability performance loss constraint.

[0007] Preferably, carrying out an analysis of the durability performance loss on the concrete flow path between the first spraying node and the second spraying node to generate the durability performance loss constraint includes: determining the spraying concrete flow characteristics of the concrete flow path; performing a moisture loss correlation analysis based on the spraying concrete flow characteristics, and generating the durability performance loss constraint with moisture loss correlation factors.

[0008] Preferably, an extreme environment configuration is carried out within the preset application environment range to generate a target test environment, including: reading multiple environmental parameter ranges in the preset application environment; analyzing the influence relationship between multiple environmental parameters and the durability performance of concrete; based on the multiple environmental parameters, selecting extreme values in the multiple environmental parameter ranges in the direction of causing the decline of the durability performance of concrete to construct the target test environment.

[0009] Preferably, the preset application environment includes the environment of the spraying wall surface of the sprayed concrete to be tested and the space environment within a preset range.

[0010] Preferably, the indoor formed specimen tooling includes a full set of spraying forming equipment configured based on a preset spraying scale and a surface flatness adjusting device.

[0011] Preferably, indoor environment control is carried out in the target test environment, durability performance loss synchronous adjustment is carried out with the durability performance loss constraint, and an indoor forming test is carried out on the sprayed concrete to be tested through the indoor formed specimen tooling. After forming, surface flatness adjustment is performed to obtain a test sample, including: configuring the environment where the spraying template is located in the target test environment. After completing the indoor environment control and durability performance loss synchronous adjustment, spraying the sprayed concrete to be tested onto the spraying template according to a preset test plan through the indoor formed specimen tooling to complete the indoor forming test; when the concrete on the spraying template is formed, performing grinding with a preset surface flatness as the target through the surface flatness adjusting device to obtain the test sample, wherein the preset surface flatness is the required flatness of the test index of the durability performance.

[0012] Preferably, perform a durability performance test on the test sample, establish a durability life estimation model for predicting the durability life, and generate a durability performance test result, including: constructing associated test indexes for the durability performance; performing a durability performance test on the test sample based on the associated test indexes, and constructing the durability life estimation model according to the test result; predicting the time node when the durability performance does not meet the preset performance threshold by using the durability life estimation model, and generating the durability performance test result, wherein the preset performance threshold is the critical threshold at which the concrete layer does not meet the standard safety index.

[0013] Preferably, performing a durability performance test on the test sample based on the associated test indexes, and constructing the durability life estimation model according to the test result, includes: performing durability performance tests on the test sample for multiple time periods based on the associated test indexes, and generating durability performance test results for multiple periods; constructing a decay curve of the durability performance by using the durability performance test results for multiple periods and the corresponding multiple time periods; and constructing the durability life estimation model by using the decay curve.

[0014] On the other hand, the present application also provides a durability performance test system for shotcrete, which is used to execute the durability performance test method for shotcrete as described above, and includes: a preset parameter acquisition module, configured to read the preset spraying process and the preset application environment of the shotcrete to be tested; a test environment configuration module, configured to perform extreme environment configuration within the range of the preset application environment to generate a target test environment; a durability performance loss analysis module, configured to perform an analysis of the durability performance loss of the concrete based on the preset spraying process, and construct a durability performance loss constraint; a test sample acquisition module, configured to perform indoor environment control with the target test environment, perform synchronous adjustment of the durability performance loss with the durability performance loss constraint, perform an indoor forming test on the shotcrete to be tested through an indoor forming specimen tooling, and perform surface flatness adjustment after forming to obtain a test sample; and a durability performance test module, configured to perform a durability performance test on the test sample, establish a durability life estimation model for predicting the durability life, and generate a durability performance test result.

[0015] One or more technical solutions provided in the present application have at least the following beneficial effects: By reading the preset spraying process and application environment before the test, the prerequisite conditions for the test can be clarified, providing a basis for subsequent test environment configuration, performance loss analysis, etc., making the test more targeted. By performing extreme environment configuration within the preset application environment range, the most severe environmental conditions that shotcrete may encounter in actual applications are simulated, so as to comprehensively evaluate the durability changes of shotcrete under different service conditions and make the test results more representative. Based on the preset spraying process, an analysis of the durability performance loss of concrete is carried out to construct a durability performance loss constraint: quantify the durability performance attenuation that occurs during the construction process, so as to compensate and adjust during the subsequent test process to ensure that the test data can accurately reflect the actual durability performance of shotcrete. Prepare test samples under the condition of simulating the real environment and considering performance loss. The synchronous adjustment of indoor environment control and performance loss ensures that the preparation conditions of the test samples are consistent with the actual situation, and the adjustment of surface flatness further improves the quality of the test samples, making the test samples consistent with the engineering site in terms of environmental conditions, improving the representativeness of laboratory specimens, and reducing the deviation from the actual project. After obtaining the specimens, conduct durability tests on them, and construct a durability life estimation model in combination with the experimental data to improve the accuracy of the test results of the durability performance of shotcrete and provide direct data support for engineering applications.

[0016] In summary, by simulating extreme environments and considering performance losses during the construction process, the present application can more realistically evaluate the durability performance of shotcrete, not only improving the accuracy and reliability of the test results, but also better reflecting the performance of shotcrete in actual projects, providing a more scientific and practical reference for engineering design, construction, and maintenance.

[0017] The above description is only an overview of the technical solution of the present application. In order to be able to more clearly understand the technical means of the present application, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features, and advantages of the present application more obvious and understandable, the following specifically gives the specific implementation manners of the present application. Brief Description of the Drawings

[0018] Figure 1 It is a schematic flowchart of the durability performance test method for shotcrete provided by an embodiment of the present application.

[0019] Figure 2 It is a schematic flowchart of constructing a durability performance loss constraint in the durability performance test method for shotcrete provided by an embodiment of the present application.

[0020] Figure 3 It is a schematic flowchart of generating a target test environment in the durability performance test method for shotcrete provided by an embodiment of the present application.

[0021] Figure 4Schematic diagram of the durability performance test system for shotcrete provided by the embodiments of the present application.

[0022] Explanation of reference numerals: preset parameter acquisition module 10, test environment configuration module 20, durability performance loss analysis module 30, test sample acquisition module 40, durability performance test module 50. Specific implementation manners

[0023] By providing a durability performance test method and system for shotcrete, the embodiments of the present application solve the technical problem that in the prior art, due to the insufficient consideration of the durability performance loss of shotcrete during the construction process and the comprehensive influence of the actual application environment, the test results deviate from the actual engineering applications, and achieve the technical effect of improving the accuracy of the durability performance test of shotcrete and the engineering applicability.

[0024] Embodiment 1, as Figure 1 shown, the embodiments of the present application provide a durability performance test method for shotcrete, and the method includes: Step S1: Read the preset spraying process and preset application environment of the shotcrete to be tested.

[0025] Specifically, shotcrete is a concrete material constructed by high-pressure spraying method, and is commonly used in projects such as tunnels, mines, slopes, etc. The preset spraying process refers to a series of process settings related to spraying operations such as the spraying operation sequence, spraying speed, spraying angle, etc. planned before the shotcrete construction. For example, in a building exterior wall reinforcement project, the preset spraying process may stipulate that the spraying angle is 90 degrees with the wall surface, and the spraying speed is 5 meters per second, etc. The preset application environment refers to the pre-set environmental conditions where the shotcrete will be used, including temperature, humidity, whether there are chemical erosion substances, etc. For example, in a building project by the sea, the preset application environment is an environment with high humidity and a risk of chloride ion erosion. Through a data reading device or manual input, the parameter information related to the preset spraying process and application environment is obtained. For example, this information can be extracted from the engineering design drawings or construction plan documents, or the engineering data management software can be used to read the relevant data stored in the database.

[0026] The preset spraying process and preset application environment provide basic data for the subsequent durability performance test, enabling the test to be customized according to the actual usage of the shotcrete, and improving the pertinence and accuracy of the test.

[0027] Step S2: Perform extreme environment configuration within the range of the preset application environment to generate a target test environment.

[0028] Specifically, the target test environment is the environmental conditions for conducting the durability performance test of shotcrete, aiming to comprehensively evaluate the durability performance of concrete under extreme conditions. The preset application environment information obtained in step S1 covers the variation ranges of various environmental factors that shotcrete may encounter in actual applications. Within the preset application environment range, the most adverse and challenging combination of environmental conditions is selected and set as the target test environment to simulate the extreme situations that shotcrete may encounter in actual applications. For example, the temperature is set to the lowest or highest value, the humidity is set to the highest or lowest value, and a high-concentration chemical corrosion medium is introduced, etc. Exemplarily, if the temperature range in the preset application environment is -20°C to 40°C, the humidity range is 30% to 95%, and the chemical corrosion medium concentration range is from low concentration to medium concentration, etc., then -20°C and 40°C can be selected as the extreme temperature values; 30% and 95% can be selected as the extreme humidity values; for the chemical corrosion medium, it can be configured according to its maximum concentration in the preset environment, such as a high-concentration chloride solution (such as 3% sodium chloride solution) or a high-concentration sulfate solution (such as 10% sodium sulfate solution).

[0029] By simulating extreme environmental conditions, comprehensively evaluate the durability performance of shotcrete under the most adverse conditions in actual applications to ensure that the test results have sufficient safety and reliability reserves.

[0030] Step S3: Based on the preset spraying process, conduct an analysis of the durability performance loss of concrete and construct a durability performance loss constraint.

[0031] Specifically, the durability performance loss of concrete refers to the phenomenon that when shotcrete is sprayed under the preset spraying process, due to the influence of various factors, the durability performance indicators of the concrete (such as compressive strength, frost resistance, impermeability, carbonation performance, etc.) are reduced compared with the initial design values. For example, during the transportation and construction of wet concrete, due to reasons such as too long time, temperature change, and insufficient vibration, the uniformity of the concrete may decrease and the strength may be reduced. The analysis of the durability performance loss of concrete first requires a detailed analysis of the preset spraying process to find out the links that may lead to the durability performance loss. For example, analyze the influence of factors such as the transportation time, parking time, spraying speed, and spraying thickness of the concrete on the durability performance. Then, through a combination of experimental research and theoretical calculation, determine the quantitative relationship between these factors and the durability performance loss.

[0032] The durability performance loss constraint refers to a series of compensation or adjustment measures set during the experiment to reflect the durability loss occurring during the construction process. When constructing the durability performance loss constraint, statistical analysis methods can be used to determine the allowable performance loss range based on the analysis results of the concrete durability performance loss and convert it into specific construction parameter constraints. For example, according to the specific parameter settings in the preset spraying process, constraint parameters such as simulated transportation duration, test parking time, and test spraying speed are set. These constraint conditions will serve as an important basis for subsequent indoor forming tests to ensure that the durability performance loss can be adjusted synchronously during the test process.

[0033] By incorporating the impact of the spraying process on the durability performance into the test system, the test results are made more in line with the actual construction situation, improving the accuracy and reliability of the test results.

[0034] Step S4: Conduct indoor environmental control in the target test environment, perform synchronous adjustment of the durability performance loss according to the durability performance loss constraint, conduct an indoor forming test on the to-be-tested shotcrete through an indoor forming specimen tooling, and perform surface flatness adjustment after forming to obtain a test sample.

[0035] Specifically, inside the laboratory, according to the requirements of the target test environment, professional environmental adjustment equipment is used to precisely control the temperature, humidity, chemical medium, etc. of the test environment within the range required by the target test environment. For example, a high and low temperature alternating damp heat test chamber is used to simulate extreme temperature and humidity conditions, and by adjusting the temperature and humidity parameters of the test chamber, it is made to reach the set extreme values. For a chemical corrosion environment, the specimens can be immersed in the prepared chemical solution or corresponding chemical gases can be introduced into the test chamber. While controlling the environment, the construction process parameters of the shotcrete are synchronously adjusted according to the durability performance loss constraint. For example, the transportation time of the wet concrete is controlled at 20 minutes, the spraying speed is 12 cubic meters per hour, and the spraying thickness is 8 centimeters to simulate the performance loss situation in actual construction. Use indoor forming specimen tooling such as a spraying trolley and molds to make specimens according to the adjusted process parameters. After the specimens are formed, tools such as trowels and grinders are used to perform surface flatness adjustment on them to make the surface flatness meet the standard requirements (such as the flatness error not exceeding 2 millimeters) to obtain the final test sample.

[0036] Through precise environmental control and performance loss adjustment, it is ensured that the preparation process of the test sample can truly reflect the situation in the actual construction and application environment, improving the representativeness of the test sample and the accuracy of the test results.

[0037] Step S5: Conduct durability performance tests on the test sample, establish a durability life estimation model for durability life prediction, and generate durability performance test results.

[0038] Specifically, the durability performance of the test samples is tested in accordance with the relevant standards and specifications of shotcrete to evaluate their durability performance indicators. Common test items include frost resistance (such as the relationship between the number of freeze-thaw cycles and strength loss), impermeability (such as determination of impermeability grade), carbonation performance (such as measurement of carbonation depth), chemical erosion resistance (such as mass change and strength change in specific chemical media), etc. These tests can reflect the durability of concrete under different environmental conditions. For example, a rapid freeze-thaw tester is used for frost resistance testing, and the operation is carried out according to the method in the test standard document. The relative dynamic elastic modulus and mass loss rate of the test specimens at different numbers of freeze-thaw cycles are recorded to evaluate their frost resistance grade. For impermeability testing, an impermeability tester can be used. The test specimens are placed under a certain water pressure, and their water seepage situation is observed to determine the impermeability grade. The carbonation performance test can be completed by exposing the test specimens to a carbon dioxide environment and regularly measuring their carbonation depth.

[0039] After obtaining the durability performance test data, a durability life estimation model is established. This model is used to predict the service life of shotcrete based on the durability performance test results. Based on a large amount of experimental data and actual engineering cases, through statistical analysis and theoretical derivation (methods such as regression analysis and neural networks can be used), the test data is correlated with environmental factors, construction parameters, etc. to establish a prediction model. For example, by analyzing the relationships between indicators such as frost resistance and impermeability and factors such as environmental temperature, humidity, and chemical medium concentration, as well as the relationship with performance loss during the construction process, a multiple regression model is established to predict the durability life of shotcrete in actual applications and obtain the durability performance test results.

[0040] Through comprehensive durability performance testing and scientific life prediction, it provides direct data support for engineering design and maintenance, and helps to reasonably evaluate the service life and reliability of shotcrete in actual projects.

[0041] Furthermore, as Figure 2 shown, step S3 of the embodiment of the present application includes: Step S31: Analyze the preset spraying process and establish multiple spraying process nodes.

[0042] Step S32: Extract the first spraying node and the second spraying node from the multiple spraying process nodes, where the first spraying node and the second spraying node are two sequentially connected nodes.

[0043] Step S33: Conduct a durability performance loss analysis on the concrete flow path between the first spraying node and the second spraying node to generate the durability performance loss constraint.

[0044] Specifically, first, a detailed analysis of the preset spraying process is carried out to determine each stage from concrete preparation to the final spraying completion, and it is divided into several specific spraying process nodes, with each node corresponding to a specific construction link. For example, the spraying process can be decomposed into the following nodes: mixing node: mixing raw materials such as cement, sand, stone, and admixtures according to a predetermined ratio; pumping node: the mixture enters the pipeline through a delivery pump, and material segregation or pressure loss may occur; spraying node: the concrete is sprayed out at high speed through a nozzle and adheres to the substrate, while being affected by wind speed and rebound; forming node: the sprayed concrete gradually accumulates and solidifies. By decomposing the complex preset spraying process, it is convenient to conduct a detailed analysis and processing of each link in the process later, making the analysis more systematic and targeted.

[0045] Among the multiple established spraying process nodes, two adjacent nodes are selected as the first spraying node and the second spraying node in the process sequence. Among them, the first spraying node is the previous node, and the second spraying node is the node immediately following the first spraying node. For example, the mixing node can be selected as the first spraying node, and the transportation node can be selected as the second spraying node.

[0046] A detailed analysis of the concrete flow path between the first spraying node and the second spraying node is carried out. First, determine the specific operations and environmental conditions of the concrete in the flow path, such as transportation time, temperature change, vibration conditions, etc. Then, through a combination of experimental research and theoretical calculation methods, evaluate the impact of these factors on the durability performance of the concrete, so as to generate durability performance loss constraints. By analyzing and restricting the durability performance loss, ensure that the performance of the sprayed concrete is effectively controlled during the construction process, improve the accuracy and reliability of the test results, and make it more in line with the actual engineering application situation.

[0047] Furthermore, step S33 of the embodiment of the present application includes: Step S331: Determine the flow characteristics of the sprayed concrete in the concrete flow path.

[0048] Step S332: Perform moisture loss correlation analysis based on the flow characteristics of the sprayed concrete, and generate the durability performance loss constraint with moisture loss correlation factors.

[0049] Specifically, the flow characteristics of shotcrete refer to the characteristics related to the flow of shotcrete in the concrete flow path, such as the flow velocity of the concrete, the residence time during the flow process, and the pressure change during the flow process. Observe and record the concrete flow path between the first shot node and the second shot node in detail, and determine the flow characteristics of the shotcrete in this path in combination with the parameter settings of relevant equipment and the actual engineering situation. For example, sensors can be used to obtain data related to the concrete flow path, such as a flow velocity sensor to measure the flow velocity of the concrete in the pipeline; information such as the residence time can also be obtained through engineering records.

[0050] The factors associated with moisture loss refer to the factors that have a direct or indirect relationship with the moisture loss of shotcrete during the flow process, including the flow velocity and residence time in the flow characteristics, as well as the temperature and humidity of the flow environment. For example, a slower flow velocity may cause more moisture in the concrete to evaporate into the surrounding environment; a flow environment with high temperature and low humidity will accelerate the moisture loss of the concrete. Based on the determined flow characteristics of the shotcrete, analyze the correlation between these flow characteristics and moisture loss, and at the same time consider the influence of factors such as temperature and humidity in the flow environment on moisture loss. By establishing a mathematical model or referring to existing experimental data, integrate these factors related to moisture loss to generate durability performance loss constraints. For example, according to the experimental data of the moisture loss rate of concrete at different flow velocities and temperatures, establish a mathematical model containing variables such as flow velocity and temperature, and generate durability performance loss constraints related to moisture loss based on this model, including the stationary duration in the environment, the contact area with the external environment, etc.

[0051] Considering the durability performance loss of shotcrete during the flow process from the perspective of moisture loss, the durability performance loss constraints generated by comprehensively considering the factors associated with moisture loss can more accurately reflect the impact of the flow process on the overall durability performance of shotcrete, further improving the accuracy of the durability performance loss analysis.

[0052] Furthermore, as Figure 3 shown, step S2 of the embodiment of the present application includes: Step S21: Read multiple environmental parameter ranges in the preset application environment.

[0053] Step S22: Analyze the influence relationship between multiple environmental parameters and the durability performance of concrete.

[0054] Step S23: Based on the multiple environmental parameters, select the extreme values in the multiple environmental parameter ranges in the direction of decreasing the durability performance of concrete to construct the target test environment.

[0055] Specifically, by means of a data reading device or querying a database storing preset application environment information, multiple environmental parameter ranges are obtained, including but not limited to temperature range, humidity range, wind speed range, and pH range.

[0056] Utilize existing research results, experimental data, and theoretical models on concrete durability to analyze the relationship between the multiple environmental parameters read and the durability performance of concrete. This can be achieved by consulting relevant engineering research reports, academic papers, or performing regression analysis on the collected experimental data using data analysis software. For example, in an experiment controlling humidity and temperature, based on the test data of the concrete's impermeability under different conditions, a relationship model between temperature, humidity, and concrete performance is established using statistical analysis software.

[0057] According to the influence relationship between the environmental parameters and the durability performance of concrete obtained from the analysis, determine the extreme values in the direction of the decline in concrete durability performance within multiple environmental parameter ranges. For example, if it is known that high humidity and high acidity reduce the durability performance of concrete, then select the maximum values from the environmental parameter ranges of humidity and acidity to construct the target test environment.

[0058] Through environmental parameter reading, influence relationship analysis, and extreme environment configuration, a most challenging target test environment can be scientifically defined, and based on this, the durability test of shotcrete is carried out. This process ensures the accuracy of the test data and the representativeness of the experimental environment, enabling the test results to fully reflect the true performance of concrete under the most extreme environmental conditions, providing a reliable basis for engineering quality assessment and construction guidance.

[0059] Furthermore, the preset application environment includes the environment of the shotcrete wall surface to be measured and the spatial environment within a preset range.

[0060] Specifically, the environment of the shotcrete wall surface refers to the environmental conditions around the wall surface to which the shotcrete will adhere, including factors such as the temperature and humidity of the wall surface, the roughness of the wall surface, and whether there are pollutants on the wall surface. These factors will affect the bonding performance and early hardening process of the concrete. The spatial environment within the preset range refers to the environmental conditions of the space centered on the shotcrete wall surface within a preset certain range. This range can be set according to the actual engineering situation. For example, in an indoor construction project, the preset range may be the space within 5 meters around the shotcrete wall surface. The environmental factors therein include air temperature, humidity, and whether there are chemically corrosive gases, etc. These factors will affect the long-term durability performance of the concrete. Exemplarily, for a tunnel project, the environment of the shotcrete wall surface includes: the wall surface roughness is Ra3.0 microns, the moisture content is 5%, and the temperature is 20°C; the spatial environment within the preset range includes: the temperature range is 10°C to 30°C, the humidity is 60% to 90%, and there are low concentrations of carbon dioxide and sulfur dioxide gases.

[0061] The durability performance of shotcrete is not only affected by the wall surface environment but also by the surrounding space environment. Incorporating both the environment of the shotcrete wall surface and the space environment within a preset range into the category of the preset application environment makes the consideration of the application environment of shotcrete more comprehensive. During the testing process, the actual situation can be simulated more accurately. For example, in the shotcrete project of a seaside building, the wall surface may be eroded by seawater, and at the same time, the high humidity and salt in the surrounding space environment will also affect the durability performance of the concrete. This comprehensive setting of the application environment helps to improve the accuracy of the performance evaluation of shotcrete.

[0062] Furthermore, the indoor specimen forming tooling includes a complete set of shotcrete forming equipment configured based on a preset shotcrete scale, and a surface flatness adjusting device.

[0063] Specifically, the preset shotcrete scale refers to the scale size of shotcrete preset in engineering design or planning, including indicators such as the spraying area, thickness, and volume. For example, in the reinforcement project of a large bridge pier, the preset shotcrete scale can be a shotcrete layer with a spraying area of 100 square meters and a thickness of 10 centimeters; while in the repair project of small building components, the preset shotcrete scale can be a shotcrete layer with a spraying area of 5 square meters and a thickness of 5 centimeters.

[0064] The complete set of shotcrete forming equipment is a complete set of equipment used to complete the forming of shotcrete specimens, configured according to the preset shotcrete scale, including equipment such as shotcrete machines, mixers, and conveying pipelines. For example, for the production of specimens with a larger shotcrete scale, a shotcrete machine with a larger power and a mixer with a larger capacity are required to ensure the supply and spraying of concrete; while for a smaller shotcrete scale, the corresponding equipment specifications can be smaller.

[0065] The surface flatness adjusting device is equipment used to adjust the surface flatness of the formed shotcrete specimens, such as grinders, leveling tools, etc. During the process of making specimens, due to reasons such as the spraying process, the surface of the specimens may be uneven, and the surface flatness adjusting device can adjust it to the flatness that meets the test requirements.

[0066] The indoor specimen forming tooling includes a complete set of shotcrete forming equipment configured based on a preset shotcrete scale, ensuring the similarity in scale between the specimen production process and the shotcrete operation in the actual project. The specimens produced can better reflect the concrete performance in the actual project. At the same time, the presence of the surface flatness adjusting device enables the surface quality of the specimens to meet the requirements of subsequent tests. For example, during certain durability tests, the surface flatness will affect the accuracy of the test results. By adjusting the surface flatness, the test errors caused by surface unevenness can be reduced, and the reliability of the entire test process can be improved.

[0067] Furthermore, step S4 in the embodiment of the present application includes: Step S41: Configure the environment where the spraying template is located according to the target test environment. After completing the synchronous adjustment of indoor environment control and durability performance loss, spray the to-be-tested shotcrete onto the spraying template according to the preset test plan through the indoor formed specimen tooling to complete the indoor forming test.

[0068] Step S42: When the concrete on the spraying template is formed, use the surface flatness adjustment device to grind it to the target of the preset surface flatness to obtain the test sample, where the preset surface flatness is the required flatness of the test index of the durability performance.

[0069] Specifically, the spraying template is a template or sample structure for conducting indoor forming tests of shotcrete, providing an attachment basis for the shotcrete to form the shape and size of the specimens required for the test. The preset test plan refers to the spraying construction plan formulated according to standardized test requirements, including spraying angle, spraying pressure, concrete mix ratio, etc. According to the requirements of the target test environment, use environmental simulation equipment (such as high and low temperature alternating humidity test chambers, ventilation equipment, etc.) to configure the environment where the spraying template is located to achieve indoor environment control. Select a suitable spraying template material (such as concrete, wire mesh or rock base) to ensure that it can withstand the impact of the concrete and truly reflect the bonding performance of the concrete. Fix the position of the spraying template according to the preset spraying angle (such as 90° vertical spraying or 45° oblique spraying). At the same time, according to the previously constructed durability performance loss constraint, synchronously adjust the durability performance loss by adjusting the mix ratio of the shotcrete, the dosage of additives, etc. For example, if it is expected that the concrete will lose 3% of its moisture during transportation under a certain working condition, the concrete mix ratio can be adjusted in the experiment to reduce the initial moisture content by the corresponding proportion. Then, according to the preset test plan, use the indoor formed specimen tooling (such as spraying machines and other equipment) to spray the to-be-tested shotcrete onto the spraying template to complete the indoor forming test. By strictly controlling the laboratory environment, accurately simulating the construction conditions, and synchronously adjusting the durability performance loss factors, the indoor forming test is made to be as close as possible to the actual construction situation, providing a real and repeatable data basis for subsequent durability tests.

[0070] The preset surface flatness is the standard for the flatness of the shotcrete surface preset according to the requirements of the durability performance test indicators. For example, in the impermeability test, the surface flatness affects the penetration path of water on the concrete surface. The preset surface flatness requires being within a certain error range, such as the surface undulation not exceeding ±2 mm. After the concrete on the shotcrete sample is formed, a surface flatness adjustment device (such as a grinding machine and other equipment) is used to grind the formed concrete surface with the preset surface flatness as the target. The surface flatness is continuously detected by measuring tools (such as a level, a flatness measuring instrument, etc.) until the requirement of the preset surface flatness is met, thereby obtaining the test sample. Through high-precision flatness control, the consistency and comparability of the test samples are improved, providing reliable test samples for subsequent durability tests.

[0071] Further, step S5 of the embodiment of the present application includes: Step S51: Construct the associated test indicators of the durability performance.

[0072] Step S52: Conduct durability performance tests on the test sample based on the associated test indicators, and construct the durability life prediction model according to the test results.

[0073] Step S53: Predict the time node when the durability performance does not meet the preset performance threshold with the durability life prediction model, and generate the durability performance test result, where the preset performance threshold is the critical threshold for the concrete layer not meeting the standard safety indicators.

[0074] Specifically, the associated test indicators are indicators related to the durability performance of concrete and used to measure various aspects of its durability. According to the relevant standards for concrete durability, the core durability test indicators are selected, such as: compressive strength (MPa): reflecting the overall structural strength of concrete, usually measured by a compression testing machine; carbonation depth (mm): used to evaluate the erosion degree of carbon dioxide on concrete, which can be detected using phenolphthalein indicator; chloride ion diffusion coefficient (m² / s): reflecting the resistance of concrete to chloride salt erosion, commonly determined by the electro-migration test or the free diffusion test; number of freeze-thaw cycles (times): measuring the damage of concrete in the freeze-thaw environment, usually tested using a rapid freeze-thaw testing machine.

[0075] Based on the foregoing associated test indicators, special test equipment and standard test methods are used to conduct durability performance tests on the test sample. For example, an impermeability tester is used to measure the impermeability index, and a freeze-thaw cycle test chamber is used to determine the freeze-thaw resistance index, etc. Then, the obtained test results (the values of each associated test indicator) are used as data input, and a durability life prediction model is constructed using mathematical modeling methods (such as regression analysis, neural network, etc.) to predict the durability life of the shotcrete.

[0076] The preset performance threshold is the critical value at which the concrete layer does not meet the standard safety indicators. For example: the compressive strength is less than 20 MPa; the carbonation depth exceeds 10 mm; the chloride ion diffusion coefficient is greater than 2.0×10 -12 m² / s. According to the engineering standards, determine the minimum requirements for durability performance in different environments and set the preset performance threshold. Substitute the relevant test indicators of the test sample into the durability life estimation model. Through the durability life estimation model, calculate when the concrete will reach the preset performance threshold under the action of various environmental factors. The calculated time node is the critical moment when the concrete layer does not meet the standard safety indicators, and thus generate the durability performance test results. The generated durability performance test results can clearly indicate when the durability performance of the concrete will not meet the requirements, which helps engineering personnel to take timely measures, such as reinforcement, repair or replacement operations when approaching this time node, to ensure the safety and reliability of the engineering structure.

[0077] Further, step S52 of the embodiment of the present application includes: Step S521: Conduct durability performance tests on the test sample for multiple time periods based on the relevant test indicators, and generate durability performance test results for multiple periods.

[0078] Step S522: Construct a decay curve of the durability performance with the durability performance test results for multiple periods and the corresponding multiple time periods.

[0079] Step S523: Construct the durability life estimation model with the decay curve.

[0080] Specifically, the time period refers to the time period artificially divided during the durability performance test. For example, one month can be set as a time period, or one quarter can be set as a time period, etc. Conduct durability performance tests on the test sample according to the preset time period. After each test, record the corresponding performance index data and generate durability performance test results for multiple periods.

[0081] Organize the durability performance test results for multiple periods and the corresponding time periods, and use chart tools (such as Excel, Origin, etc.) to plot a decay curve of the durability performance with the time period as the horizontal axis and the durability performance index as the vertical axis to describe the trend of the concrete durability performance changing with time. For example, the decay curve of the frost resistance performance can show the decrease of the relative dynamic elastic modulus with time. By constructing the decay curve, the trend of the concrete durability performance changing with time is intuitively displayed, providing a visualization tool for subsequent life prediction.

[0082] According to the function expression of the constructed durability performance decay curve, by analyzing the characteristics of the curve (such as slope, intercept, etc.) and the relationship with the preset performance threshold, a durability life estimation model is established. For example, the decay curve is in the form of a quadratic function y = ax 2 + bx + c (where y represents the durability performance index and x represents time). When the preset performance threshold y0 is known, by solving the equation y0 = ax 2 + bx + c, the corresponding x value is obtained, and this x value is the durability life under this performance threshold, thus constructing a durability life estimation model. Exemplarily, through regression analysis, the decay curve equation of the frost resistance performance is obtained: relative dynamic elastic modulus = 90% - 2% × time (year). Using this equation to construct a durability life estimation model, it can be predicted that at the 5th year, the relative dynamic elastic modulus is 80%. The durability life estimation model constructed in this way can accurately predict the durability life of concrete based on the decay curve, providing an effective means for the durability assessment and life prediction of engineering structures.

[0083] In summary, the durability performance test method for shotcrete provided by the embodiments of the present application has the following beneficial effects: By reading the preset spraying process and application environment before the test, the prerequisite conditions for the test can be clarified, providing a basis for subsequent test environment configuration, performance loss analysis, etc., making the test more targeted. By performing extreme environment configuration within the preset application environment range, the most severe environmental conditions that shotcrete may encounter in actual application are simulated, so as to comprehensively evaluate the durability changes of shotcrete under different service conditions and make the test results more representative. Based on the preset spraying process, the analysis of the durability performance loss of concrete is carried out to construct a durability performance loss constraint: quantify the durability performance decay occurring during the construction process, so as to perform compensation and adjustment during the subsequent test process to ensure that the test data can accurately reflect the actual durability performance of shotcrete. Prepare test samples under the condition of simulating the real environment and considering performance loss. Indoor environment control and synchronous adjustment of performance loss ensure that the preparation conditions of the test samples are consistent with the actual situation, and the adjustment of surface flatness further improves the quality of the test samples, making the test samples consistent with the engineering site in terms of environmental conditions, improving the representativeness of laboratory specimens, and reducing the deviation from the actual project. After obtaining the specimens, conduct durability tests on them, and construct a durability life estimation model in combination with the experimental data to improve the accuracy of the test results of the durability performance of shotcrete and provide direct data support for engineering applications.

[0084] Generally speaking, by simulating extreme environments and considering performance losses during the construction process, the embodiments of the present application can more realistically evaluate the durability performance of shotcrete, not only improving the accuracy and reliability of test results, but also better reflecting the performance of shotcrete in actual projects, providing a more scientific and practical reference for engineering design, construction, and maintenance.

[0085] Embodiment 2, as Figure 4 shown, based on the same inventive concept as the aforementioned Embodiment 1, the embodiments of the present application provide a durability performance test system for shotcrete, and the system includes: A preset parameter acquisition module 10, configured to read the preset spraying process and preset application environment of the to-be-tested shotcrete.

[0086] A test environment configuration module 20, configured to perform extreme environment configuration within the range of the preset application environment to generate a target test environment.

[0087] A durability performance loss analysis module 30, configured to perform analysis on the durability performance loss of the concrete based on the preset spraying process and construct a durability performance loss constraint.

[0088] A test sample acquisition module 40, configured to perform indoor environment control in the target test environment, perform synchronous adjustment of the durability performance loss based on the durability performance loss constraint, perform an indoor forming test on the to-be-tested shotcrete through an indoor forming specimen tooling, and perform surface flatness adjustment after forming to obtain a test sample.

[0089] A durability performance test module 50, configured to perform a durability performance test on the test sample, establish a durability life estimation model for durability life prediction, and generate a durability performance test result.

[0090] Furthermore, the durability performance loss analysis module 30 of the embodiments of the present application is further configured to perform the following steps: Analyze the preset spraying process, establish multiple spraying process nodes; extract a first spraying node and a second spraying node from the multiple spraying process nodes, where the first spraying node and the second spraying node are two sequentially connected nodes; perform analysis on the durability performance loss of the concrete flow path between the first spraying node and the second spraying node to generate the durability performance loss constraint.

[0091] Furthermore, the durability performance loss analysis module 30 of the embodiments of the present application is further configured to perform the following steps: Determine the flow characteristics of the shotcrete in the concrete flow path; perform moisture loss correlation analysis based on the flow characteristics of the shotcrete, and generate the durability performance loss constraint with moisture loss correlation factors.

[0092] Further, the test environment configuration module 20 of the embodiment of the present application is further configured to perform the following steps: Read multiple ranges of environmental parameters in the preset application environment; analyze the influence relationship between multiple environmental parameters and the durability performance of concrete; based on the multiple environmental parameters, select the extreme values in the multiple ranges of environmental parameters in the direction of decreasing the durability performance of concrete, and construct the target test environment.

[0093] Further, the preset application environment of the embodiment of the present application includes the environment of the sprayed wall surface of the sprayed concrete to be tested and the space environment within a preset range.

[0094] Further, the indoor formed specimen tooling of the embodiment of the present application includes a complete set of spraying and forming equipment configured based on a preset spraying scale, and a surface flatness adjusting device.

[0095] Further, the test sample acquisition module 40 of the embodiment of the present application is further configured to perform the following steps: Take the environment where the spraying template is located in the target test environment. After completing the synchronous adjustment of indoor environment control and durability performance loss, spray the sprayed concrete to be tested onto the spraying template through the indoor formed specimen tooling according to the preset test plan to complete the indoor forming test; when the concrete of the spraying template is formed, use the surface flatness adjusting device to grind it to the target of the preset surface flatness to obtain the test sample, where the preset surface flatness is the required flatness of the test index of the durability performance.

[0096] Further, the durability performance test module 50 of the embodiment of the present application is further configured to perform the following steps: Construct the associated test indexes of the durability performance; perform the durability performance test on the test sample based on the associated test indexes, and construct the durability life estimation model according to the test results; use the durability life estimation model to predict the time node when the durability performance does not meet the preset performance threshold, and generate the durability performance test result, where the preset performance threshold is the critical threshold for the concrete layer not meeting the standard safety index.

[0097] Further, the durability performance test module 50 of the embodiment of the present application is further configured to perform the following steps: Perform the durability performance test on the test sample for multiple time periods based on the associated test indexes, generate the durability performance test results for multiple periods; construct the decay curve of the durability performance with the durability performance test results for multiple periods and the corresponding multiple time periods; construct the durability life estimation model with the decay curve.

[0098] Through the foregoing detailed description of the durability performance test method of shotcrete, those skilled in the art can clearly know the durability performance test system of shotcrete in this embodiment. For the system disclosed in Embodiment 2, since it corresponds to the method disclosed in Embodiment 1, it has corresponding functional modules and beneficial effects. For the relevant parts, reference can be made to the description in the method section.

[0099] The foregoing description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. The durability test method of shotcrete is characterized by: include: Read the preset spraying process and preset application environment of the shotcrete to be tested; Perform extreme environment configuration within the preset application environment to generate a target test environment; Performing a concrete durability loss analysis based on the preset spraying process and establishing a durability loss constraint; Performing indoor environmental control with the target test environment, performing synchronous adjustment of durability performance loss with the durability performance loss constraint, performing an indoor forming test on the shotcrete to be tested by using an indoor forming specimen tooling, and performing surface flatness adjustment after forming to obtain a test sample; The test samples are subjected to a durability test, and a durability estimation model is established to predict the durability and generate durability test results.

2. The durability testing method of shotcrete according to claim 1, characterized in that: Based on the preset spraying process, the concrete durability loss analysis is performed to construct the durability loss constraint, including: Analyze the preset injection process and establish multiple injection process nodes; Extracting a first injection node and a second injection node from the plurality of injection process nodes, wherein the first injection node and the second injection node are two nodes connected sequentially; A durability loss analysis is performed on a concrete flow path between the first injection node and the second injection node to generate the durability loss constraint.

3. The durability testing method of shotcrete according to claim 2, characterized in that: Performing a durability loss analysis on the concrete flow path between the first injection node and the second injection node to generate the durability loss constraint includes: determining shotcrete flow characteristics of the concrete flow path; A moisture loss correlation analysis is performed based on the shotcrete flow characteristics, and the durability performance loss constraint is generated using moisture loss correlation factors.

4. The durability testing method of shotcrete according to claim 1, characterized in that: Perform extreme environment configuration within the preset application environment to generate a target test environment, including: Reading multiple environmental parameter ranges in the preset application environment; Analyze the influence of multiple environmental parameters on the durability of concrete; Based on the multiple environmental parameters, extreme values ​​in the direction of decreasing the durability of concrete are selected within the range of the multiple environmental parameters to construct the target test environment.

5. The durability testing method of shotcrete according to claim 4, characterized in that: The preset application environment includes the environment of the spraying wall surface of the sprayed concrete to be tested and the space environment within a preset range.

6. The durability testing method of shotcrete according to claim 1, characterized in that: The indoor molding test piece tooling includes a full set of injection molding equipment configured based on a preset injection scale, and a surface flatness adjustment device.

7. The durability testing method of shotcrete according to claim 6, characterized in that: The target test environment is used to control the indoor environment, the durability loss is synchronously adjusted according to the durability loss constraint, an indoor forming test is performed on the shotcrete to be tested by using the indoor forming test piece tooling, and surface flatness adjustment is performed after forming to obtain a test sample, including: The environment of the spraying sample is configured according to the target test environment, and after completing the indoor environment control and the synchronous adjustment of the durability performance loss, the spraying concrete to be tested is sprayed onto the spraying sample through the indoor forming test piece tooling according to the preset test plan to complete the indoor forming test; After the concrete of the sprayed template is formed, it is polished with a preset surface flatness as a target through the surface flatness adjustment device to obtain the test sample, wherein the preset surface flatness is the required flatness of the test index of durability performance.

8. The method for testing the durability of shotcrete according to claim 1, characterized in that: The test samples are subjected to durability tests, and a durability estimation model is established to predict durability, generating durability test results, including: Constructing relevant test indicators for durability performance; Performing a durability performance test on the test sample based on the associated test index, and constructing the durability estimation model according to the test results; The durability life estimation model is used to predict the time node at which the durability performance does not meet the preset performance threshold, and the durability performance test result is generated, wherein the preset performance threshold is a critical threshold at which the concrete layer does not meet the standard safety index.

9. The method for testing the durability of shotcrete according to claim 8, characterized in that: The durability performance test is performed on the test sample based on the associated test index, and the durability estimation model is constructed according to the test result, including: Based on the associated test index, the test sample is subjected to a durability performance test for multiple time periods to generate a plurality of cycle durability performance test results; Constructing a durability performance attenuation curve based on the multiple cycle durability performance test results and the corresponding multiple time periods; The durability estimation model is constructed based on the attenuation curve.

10. The durability test system of shotcrete is characterized by: The system is used to perform the durability performance testing method of shotcrete according to any one of claims 1 to 9, comprising: A preset parameter acquisition module is used to read the preset spraying process and preset application environment of the sprayed concrete to be tested; A test environment configuration module, used to perform extreme environment configuration within the preset application environment range to generate a target test environment; A durability loss analysis module, used to perform a durability loss analysis on concrete based on the preset spraying process and to construct a durability loss constraint; A test sample acquisition module is used to control the indoor environment with the target test environment, synchronously adjust the durability performance loss with the durability performance loss constraint, perform an indoor forming test on the shotcrete to be tested through an indoor forming test piece tooling, and perform surface flatness adjustment after forming to obtain a test sample; The durability performance test module is used to perform a durability performance test on the test sample, establish a durability life estimation model to predict the durability life, and generate a durability performance test result.

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