Box culvert performance optimization method and system based on concrete doping quantity control

Abstract

The application provides a box culvert performance optimization method and system based on concrete doping quantity control, relates to the doping material proportioning optimization technical field, and comprises the following steps: analyzing the structural length characteristics of a long and large frame box culvert; performing correlation analysis on the concrete doping material according to the performance parameters of the box culvert, and establishing a performance-doping material correlation list; performing matching search according to a preset performance parameter target quantity, and obtaining a performance matching doping scheme; performing length temperature stress accumulation analysis, predicting cracks according to a temperature stress gradient, and obtaining temperature gradient crack distribution; performing doping quantity and pouring process dimension compensation optimization, and obtaining optimized concrete doping quantity, which is used for concrete doping pouring control. The application solves the technical problem that in the prior art, the use of concrete doping quantity mainly depends on experience or general standards, and there is a lack of personalized proportioning design for the temperature stress characteristics of different regions of a long and large frame box culvert, thereby increasing the risk of crack generation.

Description

Technical Field

[0001] This invention relates to the field of additive ratio optimization technology, specifically to a method and system for optimizing the performance of box culverts based on concrete additive control. Background Technology

[0002] Concrete, as a major building material, is widely used in various infrastructure constructions due to its excellent strength, durability, and ease of construction. However, as the scale of structures continues to increase, especially for large-volume concrete structures such as long frame box culverts, traditional concrete pouring and construction processes face a series of technical challenges, particularly in terms of temperature stress and crack control.

[0003] During the construction of large-volume concrete, the heat released by the hydration reaction inside the concrete leads to a significant increase in temperature. Due to the temperature difference between the inside and the surface of the concrete, a temperature gradient is often generated. This temperature difference causes thermal expansion and contraction of the concrete, especially in longer structures where the temperature gradient difference is more obvious. Under these conditions, the accumulation of temperature stress can easily lead to the formation of through cracks. This problem is particularly prominent in the construction of large-volume concrete structures such as long frame box culverts. Due to their long dimensions, the concrete in long frame box culverts will shrink during the hardening process. The shrinkage of concrete may not show obvious cracks in the early stage, but as time goes by, the shrinkage gradually accumulates, causing tensile stress in the concrete, eventually leading to the appearance of cracks. This shrinkage problem has not been effectively controlled in traditional construction processes. Summary of the Invention

[0004] This application provides a method and system for optimizing the performance of box culverts based on the control of concrete admixture content. It aims to solve the technical problem that the use of concrete admixture content in the prior art mainly relies on experience or general standards, and lacks personalized mix design for the temperature stress characteristics of different areas of long concrete frame box culverts, which leads to an increased risk of cracking.

[0005] The first aspect disclosed in this application provides a method for optimizing the performance of box culverts based on concrete admixture control. The method includes: analyzing the structural length characteristics of long-length frame box culverts; performing correlation analysis on concrete admixtures according to box culvert performance parameters to establish a performance-admixture correlation list; performing a matching search on the performance-admixture correlation list based on preset performance parameter target values ​​for the long-length frame box culvert to obtain a performance-matched admixture scheme; based on the performance-matched admixture scheme, performing a length-temperature stress accumulation analysis according to structural length characteristics, predicting cracks based on temperature stress gradients to obtain temperature gradient crack distributions; and optimizing the performance-matched admixture scheme based on admixture amount and pouring process dimensions compensation according to the temperature gradient crack distribution and temperature stress gradients to obtain an optimized concrete admixture amount, wherein the optimized concrete admixture amount is used for concrete admixture pouring control.

[0006] The second aspect of this application discloses a box culvert performance optimization system based on concrete doping control. The system is used in the aforementioned box culvert performance optimization method based on concrete doping control. The system includes: a length feature analysis module for analyzing the structural length characteristics of long-length frame box culverts; a correlation analysis module for performing correlation analysis on concrete dopants according to box culvert performance parameters and establishing a performance-dopant correlation list; a matching search module for performing a matching search on the performance-dopant correlation list based on preset performance parameter target values ​​of the long-length frame box culvert to obtain a performance-matching doping scheme; a crack prediction module for performing length temperature stress accumulation analysis based on the performance-matching doping scheme and structural length characteristics, predicting cracks based on temperature stress gradients, and obtaining temperature gradient crack distributions; and a pouring control module for optimizing the doping amount and pouring process dimensions of the performance-matching doping scheme based on the temperature gradient crack distribution and temperature stress gradients to obtain an optimized concrete doping amount, which is used for concrete doping pouring control.

[0007] One or more technical solutions provided in this application have at least the following beneficial effects:

[0008] By analyzing the dimensions and structural characteristics of long frame box culverts, the stress distribution characteristics of concrete in different length regions were clarified. The structural length characteristics of long frame box culverts affect the temperature stress gradient of concrete, which provides a theoretical basis for subsequent temperature stress analysis and helps to identify potential crack areas caused by temperature gradients. By establishing a performance-admixture correlation list and matching admixtures according to the performance objectives of the box culvert, it was ensured that the selection of admixtures could accurately meet different performance requirements. This process optimized the performance of concrete, making it more durable, especially reducing the risk of cracks caused by shrinkage and temperature changes. Through temperature stress accumulation analysis based on structural length characteristics, the temperature gradient crack distribution of long frame box culverts was accurately predicted. This prediction method can identify areas with large temperature stress, thereby effectively avoiding cracks and providing data support for subsequent temperature control and process adjustments. Based on the analysis of temperature gradient crack distribution and temperature stress gradient, combined with the characteristics of admixtures, the concrete admixture amount and pouring process were optimized. This optimization can accurately control the hydration heat and temperature stress accumulation of concrete, avoid cracks caused by excessive temperature differences, and improve the crack resistance and long-term stability of concrete.

[0009] The above description is merely an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0010] Figure 1 A schematic diagram of the process for optimizing the performance of box culverts based on concrete doping control, provided in an embodiment of this application.

[0011] Figure 2 A schematic diagram of the performance optimization system for box culverts based on concrete doping control provided in this application embodiment.

[0012] Figure labeling: Length feature analysis module 10, correlation analysis module 20, matching search module 30, crack prediction module 40, pouring control module 50. Detailed Implementation

[0013] This application provides a method and system for optimizing the performance of box culverts based on the control of concrete admixture content. This solves the technical problem in the prior art where the use of concrete admixture content mainly relies on experience or general standards, and lacks personalized mix design for the temperature stress characteristics of different areas of long concrete frame box culverts, which leads to an increased risk of crack formation.

[0014] After introducing the basic principles of this application, various non-limiting embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0015] Example 1, as Figure 1 As shown in the embodiments of this application, a method for optimizing the performance of box culverts based on concrete admixture control is provided. The method includes:

[0016] Analyze the structural length characteristics of long frame box culverts.

[0017] Determining the dimensional parameters of the box culvert, such as its length, width, and height, including the overall length of the box culvert and the length of any special areas (such as curved sections or joints), requires using data from measurement or design drawings. Determining the overall structural characteristics of the box culvert, including material type, such as concrete type and type of admixtures, as well as the stress and load characteristics of different structural parts, helps to determine the distribution of temperature stress and deformation.

[0018] Based on the dimensions and structural characteristics of the box culvert, a structural mechanics model is used to perform mechanical response analysis. Methods such as finite element analysis can be employed to simulate the box culvert's response under different load conditions. Based on the analysis results, the stress characteristics of each length distribution segment are obtained. Through mechanical response analysis, the stress and deformation of different length segments are obtained. This information provides fundamental data for subsequent temperature stress accumulation analysis. The structural length characteristics refer to the relationship between the length of the long frame box culvert and the stress distribution, which provides a basis for subsequent crack prediction and doping optimization.

[0019] A correlation analysis was conducted on concrete admixtures based on the performance parameters of the box culvert, and a performance-admixture correlation list was established.

[0020] To determine the types and names of concrete admixtures, it is necessary to identify them. Concrete admixtures typically include different mineral admixtures, such as slag, fly ash, and silica fume; chemical admixtures, such as plasticizers and water-reducing agents; and other modifying materials, such as fibers and expanding agents. Each admixture has specific properties and uses, requiring the definition of its name and basic characteristics, such as dosage range and mechanism of action.

[0021] Identify and determine the key performance parameters of box culverts, such as compressive strength, tensile strength, modulus of elasticity, impermeability, and durability. Analyze the impact of each admixture on these performance parameters through experimental or theoretical studies. Different admixtures have different effects on concrete; for example, some admixtures may increase compressive strength, while others may improve durability or impermeability. Targeted control of each admixture's dosage is then performed, and its specific impact on each performance parameter is analyzed. This process can be verified experimentally or using existing research data.

[0022] The relationships between different admixtures and various performance parameters of box culverts were compiled, and a performance-admixture correlation list was constructed. This list will provide a reference for subsequent performance matching and optimization. The correlation list includes the name, category, recommended dosage range of the admixture, and its impact on various performance parameters. For example, after adding a certain admixture, the compressive strength of the box culvert may increase by 30%, while its impermeability may increase by 20%. Through this correlation list, appropriate admixture combinations can be selected for different performance targets, and the concrete admixture formula can be adjusted according to the requirements of the target performance parameters.

[0023] The performance-doping material association list is matched and searched according to the preset performance parameter target of the long frame box culvert to obtain the performance matching doping scheme.

[0024] Define the target quantities of the preset performance parameters for long frame box culverts. These targets include reducing heat of hydration, improving crack resistance, and compensating for shrinkage deformation. In the performance-dopant correlation list, find dopant combinations that meet these preset targets. For example, based on the heat of hydration characteristics of the dopants, select dopants that can effectively reduce the heat of hydration. For instance, the combined addition of fly ash, slag, and silica fume can reduce the heat of hydration and lower the peak heat of hydration. Based on the requirements for crack resistance and shrinkage compensation, select appropriate expanding agents (such as MgO expanding agent) and fibers (such as steel fibers and polypropylene fibers) to meet the performance requirements of long frame box culverts. For example, a combination of 25%–30% fly ash, 20% slag, and 5% silica fume can reduce the peak heat of hydration to ≤280 kJ / kg.

[0025] Through matching search, a concrete doping scheme that meets all preset targets in terms of comprehensive performance is finally obtained. The scheme includes the type and dosage of dopants and the combination of materials for synergistic effect, ensuring that performance targets such as heat of hydration, crack resistance, and shrinkage compensation can be effectively met.

[0026] Based on the performance matching doping scheme, length temperature stress accumulation analysis is performed according to the structural length characteristics, and crack prediction is performed based on the temperature stress gradient to obtain the temperature gradient crack distribution.

[0027] Based on the selected doping scheme, a hydration heat analysis is first performed to calculate the heat released by concrete during hydration. Each dopant, such as fly ash, slag, silica fume, MgO expansion agent, etc., has different heat release characteristics during hydration. These characteristics determine the temperature rise of concrete during hardening. The temperature of hydration heat is calculated and corrected according to the external ambient temperature to accurately simulate the temperature field.

[0028] Based on the heat of hydration temperature and its variation, temperature accumulation calculations are performed to obtain the temperature distribution at different locations in long frame box culverts. For long frame structures, the temperature distribution is usually non-uniform, especially since the internal temperature is often higher than the surface temperature. Therefore, it is necessary to calculate the temperature difference based on the dimensional characteristics of the structure. Using the temperature accumulation calculation results, temperature contour maps are plotted to display the temperature distribution and temperature gradient at each location. The temperature contour maps will show the temperature gradient distribution along the length and wall thickness of the structure, helping to identify areas with large temperature differences, which are often potential locations for cracks.

[0029] Using the temperature-stress relationship, the temperature gradient is converted into a stress distribution. Temperature differences lead to stress gradients inside the concrete. Areas with higher temperatures experience greater thermal expansion, which may lead to the accumulation of tensile stress. By analyzing the temperature-stress distribution, it can be determined which areas may experience stress exceeding the tensile strength of the material, thereby causing cracks.

[0030] Based on the distribution of temperature stress and combined with the tensile strength, elastic modulus and other properties of concrete, crack prediction is performed. Through the crack prediction model, it is determined which areas may develop through-cracks caused by temperature. Usually, these cracks will appear at the location of the greatest temperature stress. A temperature gradient crack distribution map is generated to show which locations and areas may be affected by temperature stress, leading to cracking.

[0031] Based on the temperature gradient crack distribution and temperature stress gradient, the performance matching doping scheme is optimized by compensating for the doping amount and pouring process to obtain the optimized concrete doping amount, which is used for concrete doping pouring control.

[0032] Based on the obtained temperature gradient crack distribution map and temperature stress gradient, the areas with the most obvious temperature gradient and the greatest stress in the long frame box culvert were identified. These areas may lead to cracks due to excessive temperature differences, especially in the high temperature gradient area and the low temperature gradient area with excessive temperature stress. The probability of crack occurrence is higher in these two areas, so they need to be given special attention.

[0033] Based on the prediction of crack distribution, temperature compensation of dopants is carried out for high temperature gradient zone and low temperature gradient zone, including compensation of dopant ratio and dopant material length. In addition, the distribution of temperature stress during the casting process is also affected by the casting process. Especially for long frame box culverts, segmented casting in different time periods and different areas can effectively control the accumulation of hydration heat and avoid excessive temperature gradient.

[0034] Through the optimization of temperature compensation for the admixtures and the adjustment of the pouring process, the final optimized concrete admixture content was determined. This optimized admixture content effectively meets the requirements for temperature stress control, crack prediction, and structural performance. Actual pouring control was implemented using the optimized concrete admixture content. During the pouring process, the admixture content in each area was strictly controlled to ensure uniform distribution of the admixture.

[0035] Furthermore, the analysis of the structural length characteristics of the long frame box culvert includes:

[0036] Obtain the length dimensions and structural characteristics of the long frame box culvert; perform mechanical response analysis based on the length dimensions and structural characteristics to obtain the stress characteristics of each length distribution of the long frame box culvert, and obtain the structural length characteristics.

[0037] Determine the basic geometric parameters of the box culvert, such as its total length, width, and height. These data can usually be obtained through design drawings or on-site measurements. For long frame box culverts, in addition to the overall dimensions, it is also necessary to record the lengths of different parts, such as possible curved sections, connecting sections, or special structural sections. The dimensions of these different lengths may have different effects on temperature stress and crack formation.

[0038] Clearly define the type and characteristics of concrete used in the box culvert, such as whether high-performance concrete is used, the proportion of admixtures, and the use of other reinforcing materials. Long frame box culverts typically have specific frame structure forms, such as box-shaped structures or double-box structures. Each structural type may respond differently to temperature and stress, so this information needs to be recorded in detail. Clearly define the structural support and connection methods, such as support locations and connecting components. The support and connection methods directly affect the stress distribution and temperature stress transmission of the structure.

[0039] By collecting the above data, we obtained the complete length dimensions and structural characteristics of the long frame box culvert, providing the necessary input data for the next step of mechanical response analysis.

[0040] Based on the geometric dimensions and structural characteristics of the box culvert, a mechanical response analysis is conducted to identify the stress characteristics of the box culvert at different length distributions, providing a basis for crack prediction and optimized design. Specifically, a finite element model of the long frame box culvert is established to simulate its mechanical response under different load conditions. The finite element model needs to consider information such as the length, cross-sectional dimensions, and material properties of the box culvert, and set load conditions, including self-weight, external loads such as soil pressure, traffic loads, seismic loads, and temperature changes. The stress response of the long frame box culvert may be affected by these loads, especially when the temperature changes, the difference between the internal and external temperatures may lead to the generation of temperature stress.

[0041] By analyzing the temperature field inside the concrete and the temperature changes in the external environment, temperature stress analysis is performed. Temperature field analysis provides data on temperature stress distribution. Combined with the mechanical properties of concrete, such as elastic modulus and tensile strength, stress distribution can be derived. Mechanical analysis will give the stress characteristics at various locations of the box culvert. Based on the structural dimensions and material properties of different length sections, the stress distribution in different parts of the box culvert is analyzed, with particular attention paid to the stress changes caused by the internal and external temperature differences.

[0042] The stress in a box culvert may vary along different lengths. Some lengths may be more affected by external loads, while others may be more affected by temperature stress. For long frame box culverts, especially those spanning a long distance, temperature gradients may cause significant temperature stress. Therefore, in mechanical response analysis, special attention should be paid to the stress concentration areas caused by these temperature gradients.

[0043] Mechanical response analysis identifies areas of high stress concentration, which are typically high-risk zones for cracking. Based on the analysis results, stress distribution maps are plotted to show the stress levels of long frame box culverts across different length sections. These maps help determine which locations require more attention, especially in areas with large temperature gradients. The stress distribution and temperature stress gradients obtained from the mechanical response analysis can further refine the structural length characteristics. For example, certain sections may require reinforced design, or materials and processes may need optimization to reduce stress concentration and cracking risk.

[0044] Furthermore, the correlation analysis of concrete admixtures based on the performance parameters of the box culvert, and the establishment of a performance-admixture correlation list, includes:

[0045] Obtain the categories and names of concrete admixtures; perform targeted adjustments on the concrete admixtures according to the box culvert performance parameters to obtain the correlation between each category of admixture and each box culvert performance parameter; integrate the correlation between all categories of admixtures and box culvert performance parameters according to the box culvert performance parameters to construct the performance-admixture correlation list.

[0046] Identifying and classifying various admixtures used in concrete, and understanding the name and characteristics of each admixture, provides data support for subsequent performance control analysis. Specifically, concrete admixtures can be divided into several categories, including: mineral admixtures such as fly ash, slag, silica fume, and natural volcanic ash, which can improve the compressive strength, impermeability, and durability of concrete; chemical admixtures such as water-reducing agents, plasticizers, expanding agents, and early-strength agents, which are usually used to improve the workability of concrete, increase early strength, and control shrinkage; fiber admixtures such as steel fibers, polypropylene fibers, and glass fibers, which are usually used to enhance the crack resistance and shear strength of concrete; and other admixtures such as bentonite, fiber-reinforced materials, and nanomaterials.

[0047] For each type of admixture, its specific name is determined, along with its characteristics, including its chemical composition, physical properties such as particle size distribution and specific surface area, and their specific impact on concrete performance. Through the classification and characteristic analysis of admixtures, the name and basic characteristics of each admixture are obtained, providing data support for subsequent performance control.

[0048] Through experimental or theoretical analysis, the specific impact of each admixture on the performance parameters of the box culvert is determined, and the correlation between them is established. Specifically, the performance parameters of the box culvert are defined, including compressive strength, tensile strength, elastic modulus, impermeability, and durability. Based on the characteristics of each admixture, its impact on different performance parameters is determined. For example, fly ash has good impermeability and durability, reduces heat of hydration, and is suitable for large-volume concrete, but its contribution to compressive strength is relatively small; slag can improve the compressive strength and impermeability of concrete, especially in high-temperature and high-humidity environments; silica fume can significantly improve compressive strength and increase durability, but it usually needs to be used in moderation, because excessive use may reduce the workability of concrete.

[0049] Each admixture is used to adjust the performance of concrete by different dosage adjustments. Through experimental data, a directional control relationship between each admixture and the performance parameters of the box culvert is established. For example, experiments are conducted to obtain the specific effects of different dosages of fly ash, slag, silica fume, etc. on properties such as compressive strength and impermeability. Using these experimental results, the correlation between admixtures and various performance parameters is formed, further supporting the customized design of concrete performance.

[0050] Based on the directional control relationship, the correlation between each admixture and the performance parameters of the box culvert is systematically organized. For example, the influence of different admixtures on compressive strength, tensile strength, impermeability, and durability is listed, and their optimal dosage range is recorded. The influence information of all admixtures is integrated and summarized into a complete correlation list. The correlation list will provide strong support for the subsequent concrete mix design and help select appropriate admixture combinations to meet the requirements of different box culvert performance parameters.

[0051] Furthermore, the performance parameters of the box culvert include: compressive strength, tensile strength, elastic modulus, impermeability, and durability.

[0052] The performance parameters of box culverts include compressive strength, tensile strength, modulus of elasticity, impermeability, and durability. Among them, compressive strength is the strength of concrete under compression and is usually an important indicator for evaluating concrete quality; tensile strength is the strength of concrete under tension. Although the tensile strength of concrete is generally low, it is still important in some applications; modulus of elasticity describes the ability of concrete to deform within its elastic range and is closely related to the stiffness and deformation characteristics of concrete; impermeability is the resistance of concrete to water penetration, usually assessed through impermeability tests, and directly affects the durability of concrete; durability includes frost resistance, resistance to chemical attack, and resistance to aging, affecting the long-term performance of concrete in harsh environments.

[0053] Furthermore, this includes:

[0054] Multiple experimental combinations were configured based on the types of concrete admixtures; adiabatic temperature rise experiments were conducted on each of the multiple experimental combinations to analyze the heat release law of concrete hydration; based on the heat release law of concrete hydration, combined with the external ambient temperature, temperature field and stress field coupled experimental analysis was conducted to establish the temperature-stress relationship.

[0055] Based on the characteristics of each dopant and its impact on performance, multiple experimental combinations are configured. For example, low-doping experiments use a lower proportion of dopant, such as 10%~15% fly ash, 10%~15% slag, and 3%~5% silica fume; high-doping experiments use a higher proportion of dopant, such as 25%~30% fly ash and 20%~25% slag, to evaluate its impact on heat of hydration, compressive strength, etc.; combined experiments use different combinations of various dopants, such as a composite blend of fly ash, slag, and silica fume, to study their synergistic effects.

[0056] Depending on the specific application objectives, such as compressive strength and impermeability, the dosage of admixtures in each experimental group is adjusted. Different admixtures have different effects on hydration heat release and shrinkage performance, therefore, it is necessary to combine different types of admixtures to optimize the overall performance of concrete. Through the above design, multiple experimental combinations are generated, each containing different combinations and dosages of admixtures, ensuring that the influence of admixtures on concrete hydration heat, temperature stress, etc., can be comprehensively evaluated in the experiment.

[0057] This study investigates the heat release pattern during concrete hydration through adiabatic temperature rise experiments, aiming to understand the influence of admixtures on the peak heat of hydration and heat release rate. Specifically, a calorimeter, such as a cement calorimeter, is used to monitor the heat released during concrete hydration. The concrete hydration reaction is simulated in a closed environment under adiabatic conditions, where heat loss is not allowed to ensure accurate hydration heat data. Each concrete sample is placed in the calorimeter in a laboratory environment, and temperature changes at different time points are recorded. The hydration heat release rate and total heat are calculated using the temperature change data. The temperature rise of the concrete from the start of pouring to the release of hydration heat is recorded, and hydration heat release curves for different admixture groups are obtained.

[0058] By analyzing experimental data, this study elucidates the heat release pattern of concrete hydration heat. Specifically, it identifies the peak heat release during the hydration process of each concrete group and observes the impact of different admixtures on the peak heat release. For example, certain admixtures (such as fly ash and slag) can significantly reduce the peak heat release of hydration heat, thereby reducing the temperature gradient of the concrete. The study also analyzes the impact of different admixtures on the heat release rate of hydration heat. For instance, silica fume may increase the heat release rate of hydration heat, while certain mineral admixtures (such as fly ash) may delay the release of hydration heat. Finally, it calculates the total heat generated during the hydration process for each experimental group to understand the influence of admixtures on the heat of hydration, thus providing data support for subsequent temperature stress analysis.

[0059] Based on the results of the adiabatic temperature rise experiment, the influence of each admixture on the peak heat of hydration, release rate and heat accumulation was summarized, which helps to analyze the changes in temperature field and stress field of concrete under different environments.

[0060] In practical temperature and stress field coupling analysis, in addition to considering the release of hydration heat within the concrete, it is also necessary to consider the temperature changes in the external environment, such as air temperature and construction ambient temperature. External temperature changes affect the temperature distribution on the concrete surface, thereby influencing the formation of temperature gradients and the distribution of internal temperature stress. Based on the obtained hydration heat release pattern and external ambient temperature, numerical simulation methods, such as finite element analysis, are used to analyze the temperature field of the concrete. This temperature field analysis considers the hydration heat release, external ambient temperature, and the thermal conductivity characteristics of the concrete, yielding the temperature distribution of the concrete at various times.

[0061] Based on the temperature field analysis results, the stress field induced by temperature is further calculated. Temperature differences cause expansion or contraction in different areas of concrete, thus generating stress. The stress field analysis considers material properties such as the thermal expansion coefficient and elastic modulus of concrete, calculating the temperature stress in different areas. Through the coupled analysis of the temperature and stress fields, the relationship between temperature and stress is derived, which is usually manifested as stress changes caused by temperature differences. For example, areas with excessive temperature differences may lead to larger tensile stresses. A temperature-stress-tensile relationship model is established to clarify the specific impact of temperature changes on the stress distribution of concrete, which is helpful for subsequent crack prediction and design optimization.

[0062] Furthermore, multiple experimental combinations were configured based on the type of concrete admixture, including:

[0063] For each type of concrete admixture, different dosage gradients are configured to construct multiple sets of dosage experimental combinations for each type; based on the multiple sets of dosage experimental combinations for each type, admixtures of different lengths are configured according to the material length of each type to construct multiple sets of length experimental combinations for multiple types; the multiple sets of dosage experimental combinations for each type are merged and integrated with the multiple sets of length experimental combinations for multiple types to obtain the multiple sets of experimental combinations.

[0064] Each type of concrete admixture possesses different characteristics, affecting various concrete properties. Different dosage gradients are configured for each type of concrete admixture. For example, for fly ash, different dosage gradients are set, such as 10%, 15%, 20%, 25%, and 30%, with the goal of each gradient being to examine its impact on concrete performance. For silica fume, dosage gradients are set at 3%, 5%, 7%, and 10%, etc., to evaluate the effects of silica fume on heat of hydration, compressive strength, and durability. For each admixture category, multiple different dosage experimental combinations are designed to ensure that each admixture is tested at different dosages. For example, for fly ash, five experimental groups can be designed, each with dosage combinations of 10%, 15%, 20%, 25%, and 30%.

[0065] The impact of each admixture on concrete is not only related to its dosage, but also to the length characteristics of its distribution. Materials of different lengths, such as fiber materials and slag particles, may produce different mechanical responses in concrete. For example, the length of steel fibers has a significant impact on the crack resistance of concrete, while the particle size and distribution of slag and fly ash will also affect the release of heat of hydration and the change of temperature field.

[0066] Different lengths of dopants were configured according to the length of each type of material. For example, steel fibers of different lengths, such as 50mm, 100mm, and 150mm, could be used to observe the effect of different fiber lengths on the crack resistance and shear strength of concrete. For fly ash and slag, combinations of materials with different particle sizes, such as combinations of fine and coarse particles, were set up to observe their effects on heat of hydration and temperature stress. Multiple dopant combinations were designed by combining the doping gradient and material length, and different doping gradients and length combinations were configured for each dopant to obtain multiple different experimental groups.

[0067] By combining the dosage test combination with the length test combination, multiple test combinations are obtained, which include all test combinations under different dosage and length conditions. At this time, all test combinations can comprehensively examine the effects of concrete admixtures on various properties, especially the changes in heat of hydration, temperature field and stress field.

[0068] Furthermore, based on the performance-matching doping scheme, length-temperature stress accumulation analysis is performed according to the structural length characteristics, and crack prediction is performed based on the temperature stress gradient to obtain the temperature gradient crack distribution, including:

[0069] Hydration heat analysis is performed based on the performance matching doping scheme and the heat release law of concrete hydration to obtain the hydration heat temperature. Temperature accumulation calculation is performed based on the hydration heat temperature, and temperature difference calculation is performed according to the length of the long frame to obtain the temperature gradient distribution. The hydration heat temperature distribution is aligned with the external temperature positioning of each long frame to construct a temperature cloud map, which includes the temperature distribution and the temperature gradient distribution along the length and wall thickness. Based on the temperature cloud map, the temperature is converted to tensile stress using the temperature-stress relationship to obtain the temperature stress distribution in the long frame. A fusion analysis is performed based on the temperature stress distribution and the structural length characteristics to predict cracks in the long frame box culvert, and the temperature gradient crack distribution is generated according to the crack prediction probability.

[0070] Based on the hydration heat experiment results and the heat release law of hydration heat of concrete admixtures in the aforementioned steps, the heat released by different admixture combinations during the hydration process is determined. For example, different admixtures such as fly ash, slag, and silica fume will affect the release rate and peak value of hydration heat. Each admixture has different heat release characteristics. Adding mineral admixtures such as fly ash will delay the release of hydration heat, while adding silica fume may accelerate the release of hydration heat.

[0071] Using the concrete hydration heat equation, combined with the proportion of admixtures and the heat release data of cement hydration reaction, the hydration heat temperature of concrete at different time points is calculated. The calculation of the hydration heat temperature is usually based on the hydration heat release curve, which is obtained through experiments. The accumulation of concrete hydration heat over a specific time period is calculated by integration, thereby obtaining the hydration heat temperature.

[0072] In long frame box culverts, the temperature of the concrete gradually rises due to the release of heat of hydration. Temperature accumulation calculations need to consider the temperature changes of different parts of the concrete at different points in time. The rate of temperature change due to heat of hydration may differ at different locations within a long frame box culvert due to factors such as size, concrete thickness, and pouring sequence. In particular, the length of the frame can cause significant temperature differences between the interior and surface. In calculating the temperature difference, the length of the frame is considered, and the temperature change is calculated according to the geometry of the structure. Through these calculations, the temperature gradient distribution of the concrete during hydration is obtained. This distribution reflects the temperature change of the concrete's interior with location. Typically, the interior temperature of the frame is higher than the surface temperature, resulting in a significant temperature difference in long frames.

[0073] The hydration heat distribution of concrete is closely related to changes in the external environment's temperature. For example, fluctuations in the external environment's temperature affect the concrete surface temperature, while internal hydration heat causes the internal temperature to rise. Aligning the hydration heat distribution with external temperatures, such as ambient air temperature, is crucial for accurately simulating the temperature at different locations within the box culvert. Temperature field analysis software is used to visualize the temperature data, creating temperature cloud maps. These maps display the temperature distribution at various locations inside and on the surface of the concrete, typically using color gradients to represent different temperature values.

[0074] Temperature cloud map includes temperature distribution and temperature gradient distribution along the length and wall thickness. For the temperature gradient along the length, the internal temperature caused by the heat of hydration is usually higher than that on the surface, and the temperature difference may be more significant along the length of the frame. For the temperature along the wall thickness, due to the different wall thicknesses of the concrete, the heat of hydration may cause temperature differences in different thickness areas, which has an important impact on the formation of cracks in the concrete.

[0075] Temperature gradients cause temperature differences that lead to thermal expansion or contraction of concrete. The greater the temperature difference in concrete, the more significant the resulting temperature stress. The stress-stress relationship is usually established based on the thermal expansion coefficient and elastic modulus of concrete. By using the calculated hydration heat temperature distribution and external temperature data, the temperature difference at different locations is obtained. Then, combined with the material properties of concrete, such as the thermal expansion coefficient and elastic modulus, the temperature difference is converted into temperature stress. By calculating the stress distribution at the corresponding location through the temperature difference in each region of the temperature cloud map, the overall temperature stress distribution map is obtained.

[0076] The obtained temperature stress distribution map shows the stress situation inside and on the surface of concrete caused by temperature changes. Generally, temperature stress will appear in areas with large temperature differences. These areas are usually potential locations for cracks. In areas with high stress, concrete may crack, especially in places where the external surface temperature is low and the internal temperature is high.

[0077] The stress distribution of long frame box culverts is not only related to the temperature gradient, but also closely related to factors such as the length of the frame, material distribution, and casting process. Frames of different lengths may have different stress concentration areas. When predicting cracks, it is necessary to combine the temperature stress distribution with the length characteristics of the structure. For example, the longer part of the frame may have a larger temperature gradient, which makes stress more likely to concentrate, leading to an increased risk of cracks. By using finite element analysis or other numerical simulation methods, combined with the geometric characteristics of the structure and stress distribution, a fusion analysis can be performed to identify areas with a high risk of cracking.

[0078] A crack prediction model based on temperature stress and structural characteristics is used to predict cracks by combining temperature stress distribution. This model can predict the probability of crack occurrence based on factors such as stress concentration, temperature difference and tensile strength of concrete. According to the crack prediction model, the crack distribution caused by temperature gradient is obtained. The crack distribution map can clearly show which areas have a high probability of crack occurrence. Areas with high temperature difference and stress concentration are usually shown as high crack probability areas.

[0079] Furthermore, based on the temperature gradient crack distribution and temperature stress gradient, the performance-matching doping scheme is optimized in terms of doping amount and pouring process to obtain an optimized concrete doping amount, including:

[0080] Based on the temperature gradient crack distribution and temperature stress gradient, identify the high-temperature gradient region and low-temperature gradient region in the region where the crack distribution probability reaches the threshold; based on the temperature-stress relationship of the dopant, perform dopant temperature compensation on the high-temperature gradient region and low-temperature gradient region, including compensation for the dopant ratio and / or the length of the dopant material.

[0081] Based on the temperature gradient crack distribution, analyze which areas have a crack occurrence probability that reaches a predetermined threshold. For example, areas with a crack occurrence probability greater than a certain value (such as 50%) are considered high-risk crack areas. These areas have greater temperature stress and more obvious temperature gradients, resulting in a higher risk of crack occurrence.

[0082] Specifically, the high-temperature gradient zone usually refers to the area where the internal temperature of the concrete is much higher than the external ambient temperature, especially in the mid-span and haunches of the frame, where the temperature difference is large and temperature stress concentration is easy to occur. In these areas, the temperature rise rate is fast and the internal heat of hydration is released violently, resulting in a large temperature gradient, so special attention is required. The low-temperature gradient zone refers to the area where the temperature change is small. These areas are usually located at the ends or surface of the concrete frame, where the temperature rises slowly and the temperature difference is small. However, there is also local stress due to the slow release of heat of hydration. Although the temperature difference is small, there may be a risk of temperature stress accumulation, especially on the surface or thin-walled parts of the structure.

[0083] Based on the temperature stress gradient and crack distribution probability, the frame box culvert is divided into a high-temperature gradient zone and a low-temperature gradient zone. These two zones have different temperature and stress characteristics, so different design optimization strategies are needed for compensation and adjustment.

[0084] Based on the temperature-stress relationship of the dopant, the temperature stress in different regions is converted into actual tensile stress. Appropriate dopant is selected for temperature compensation based on the stress characteristics of different regions. In the high-temperature gradient region, the temperature stress is large, and it is necessary to reduce the occurrence of cracks by increasing the materials that resist cracking and compensate for shrinkage. In the low-temperature gradient region, it may be necessary to adjust the dopant ratio to reduce brittleness and optimize the heat of hydration characteristics.

[0085] Specifically, in high-temperature gradient zones, such as mid-span and haunches, the high temperature stress can easily lead to cracking. Therefore, the amount of steel fiber can be increased. Steel fiber can effectively improve the tensile strength and crack resistance of concrete and reduce cracks caused by temperature stress. The specific strategy is to increase the amount of steel fiber to 1.5%. This adjustment can significantly improve the tensile strength, which can be increased to 3.5 MPa. In order to compensate for the shrinkage deformation caused by temperature difference, MgO expansion agent, such as 10%, can be added to the high-temperature gradient zone. MgO expansion agent can effectively compensate for the shrinkage of concrete, reduce the volume change caused by temperature change, and limit the expansion rate.

[0086] In the low-temperature gradient zone, such as at the end, the temperature change is small and the heat of hydration is released slowly. Excessive silica fume may increase the brittleness of concrete. Therefore, the silica fume content can be appropriately reduced to 3% to reduce local brittleness and improve the ductility and crack resistance of concrete. In order to reduce the heat of hydration and reduce temperature stress in the low-temperature gradient zone, the fly ash content can be increased to 30%. As a mineral admixture, fly ash can effectively reduce the heat of hydration and slow down the rate of hydration reaction, thereby reducing the temperature stress caused by the heat of hydration.

[0087] Through these compensating strategies using admixtures, the accumulation of temperature stress can be effectively controlled in different temperature gradient zones, reducing the risk of cracking and improving the overall performance of concrete.

[0088] Furthermore, optimizing the performance-matching doping scheme by compensating for doping amount and pouring process dimensions to obtain optimized concrete doping amount also includes:

[0089] Identify nodes whose crack probability reaches a threshold from the temperature gradient crack distribution; divide the length of the long frame box culvert according to the node location to obtain the segmented interval; perform zone-by-zone and time-by-time pouring in the segmented interval; determine the temperature compensation amount based on the cumulative fitting of the hydration heat temperature of the zone-by-zone and time-by-time pouring to optimize the temperature stress gradient and obtain an optimized pouring process scheme.

[0090] Based on the temperature gradient crack distribution, a crack occurrence probability threshold is set. A common threshold is 50% or higher; areas exceeding this threshold are considered high-risk crack zones requiring special attention. Within the temperature gradient crack distribution, nodes with a crack probability greater than or equal to the threshold are identified. These nodes are typically located in areas of high temperature stress and significant temperature differences, possibly specific areas of long frame box culverts, such as joints, thicker sections, or external surfaces. These nodes are areas of concentrated temperature stress and have a high risk of cracking. Therefore, temperature differences need to be controlled through techniques such as phased and timed pouring to reduce crack formation.

[0091] Based on the identified high-risk nodes, their specific locations on the long frame box culvert are determined. These node locations are used to delineate areas of high or low temperature stress, helping to determine whether the frame box culvert needs to be poured in sections. Within the total length of the frame box culvert, reasonable divisions are made based on nodes with high temperature stress gradients and high crack probability. For example, if a node with a large temperature difference and high crack risk is located in a certain section of the frame, that section is considered a division interval. Each division interval should have relatively consistent hydration heat changes and temperature stress distribution to ensure effective control of temperature rise during pouring and to avoid excessive temperature differences that could lead to cracks.

[0092] Based on the aforementioned segmentation and temperature stress distribution, a segmented and phased pouring method is adopted for concrete pouring. Segmented and phased pouring can prevent excessive accumulation of temperature gradients in different areas, thereby reducing the concentration of temperature stress. Specifically, according to the structural characteristics of the frame, different zones are poured separately. For example, areas with high temperature stress need to be poured first, and other areas are poured after the temperature changes tend to stabilize. According to the release rate of hydration heat, the pouring is carried out in stages, and the pouring volume is controlled in each stage to ensure that the hydration heat is released gradually and to avoid stress concentration caused by excessively high temperature during a single pour.

[0093] By using a fitting method for the cumulative heat of hydration temperature, the temperature changes under segmented and timed pouring are calculated. Through temperature simulation, the changes in the heat of hydration temperature of concrete in different time periods and different pouring intervals are predicted. By adjusting the pouring sequence and pouring rate, it is ensured that the temperature rise in each segment can be controlled within a safe range, thereby avoiding excessive temperature differences that could lead to cracks.

[0094] Based on the fitting results of the accumulated heat of hydration temperature, the temperature compensation amount for each zone is determined. The temperature compensation amount is usually controlled by adjusting the proportion of admixtures, such as adding expansive agents or reducing admixtures with large heat release, to control the rate of temperature rise of concrete. For example, more expansive agents or fibers are used in the high temperature gradient zone to compensate for temperature shrinkage; in the low temperature gradient zone, admixtures with faster heat release are appropriately reduced to reduce the rate of temperature rise.

[0095] Based on the cumulative fitting of hydration heat temperature and temperature compensation, an optimized casting process scheme is formulated. The optimized process scheme can effectively control the temperature stress gradient, reduce temperature differences, and avoid cracks caused by excessive temperature stress. The process scheme includes the order of zoned casting, the interval of casting time, and the adjustment of the proportion of admixtures to ensure that the temperature stress in each zone is balanced.

[0096] In summary, the box culvert performance optimization method based on concrete admixture control provided in this application has the following technical effects:

[0097] By analyzing the dimensions and structural characteristics of long frame box culverts, the stress distribution characteristics of concrete in different length regions were clarified. The structural length characteristics of long frame box culverts affect the temperature stress gradient of concrete, which provides a theoretical basis for subsequent temperature stress analysis and helps to identify potential crack areas caused by temperature gradients. By establishing a performance-admixture correlation list and matching admixtures according to the performance objectives of the box culvert, it was ensured that the selection of admixtures could accurately meet different performance requirements. This process optimized the performance of concrete, making it more durable, especially reducing the risk of cracks caused by shrinkage and temperature changes. Through temperature stress accumulation analysis based on structural length characteristics, the temperature gradient crack distribution of long frame box culverts was accurately predicted. This prediction method can identify areas with large temperature stress, thereby effectively avoiding cracks and providing data support for subsequent temperature control and process adjustments. Based on the analysis of temperature gradient crack distribution and temperature stress gradient, combined with the characteristics of admixtures, the concrete admixture amount and pouring process were optimized. This optimization can accurately control the hydration heat and temperature stress accumulation of concrete, avoid cracks caused by excessive temperature differences, and improve the crack resistance and long-term stability of concrete.

[0098] Example 2 is based on the same inventive concept as the box culvert performance optimization method based on concrete admixture control in the previous examples, such as... Figure 2 As shown in the embodiment of this application, a box culvert performance optimization system based on concrete admixture control is provided. The system includes:

[0099] The length feature analysis module 10 is used to analyze the structural length characteristics of long frame box culverts.

[0100] The correlation analysis module 20 is used to perform correlation analysis on concrete admixtures according to the performance parameters of the box culvert and to establish a performance-admixture correlation list.

[0101] The matching search module 30 is used to perform a matching search on the performance-dopant association list based on the preset performance parameter target amount of the long frame box culvert to obtain a performance matching doping scheme.

[0102] The crack prediction module 40 is used to perform length temperature stress accumulation analysis based on the performance matching doping scheme and structural length characteristics, and to predict cracks based on temperature stress gradient to obtain temperature gradient crack distribution.

[0103] The pouring control module 50 is used to optimize the performance matching doping scheme by compensating for the doping amount and pouring process dimension based on the temperature gradient crack distribution and temperature stress gradient, so as to obtain the optimized concrete doping amount. The optimized concrete doping amount is used for concrete doping pouring control.

[0104] Furthermore, the length feature analysis module 10 includes the following operation steps:

[0105] Obtain the length dimensions and structural characteristics of the long frame box culvert; perform mechanical response analysis based on the length dimensions and structural characteristics to obtain the stress characteristics of each length distribution of the long frame box culvert, and obtain the structural length characteristics.

[0106] Furthermore, the correlation analysis module 20 includes the following operation steps:

[0107] Obtain the categories and names of concrete admixtures; perform targeted adjustments on the concrete admixtures according to the box culvert performance parameters to obtain the correlation between each category of admixture and each box culvert performance parameter; integrate the correlation between all categories of admixtures and box culvert performance parameters according to the box culvert performance parameters to construct the performance-admixture correlation list.

[0108] Furthermore, the performance parameters of the box culvert include: compressive strength, tensile strength, elastic modulus, impermeability, and durability.

[0109] Furthermore, the correlation analysis module 20 includes the following operation steps:

[0110] Multiple experimental combinations were configured based on the types of concrete admixtures; adiabatic temperature rise experiments were conducted on each of the multiple experimental combinations to analyze the heat release law of concrete hydration; based on the heat release law of concrete hydration, combined with the external ambient temperature, temperature field and stress field coupled experimental analysis was conducted to establish the temperature-stress relationship.

[0111] Furthermore, the correlation analysis module 20 includes the following operation steps:

[0112] For each type of concrete admixture, different dosage gradients are configured to construct multiple sets of dosage experimental combinations for each type; based on the multiple sets of dosage experimental combinations for each type, admixtures of different lengths are configured according to the material length of each type to construct multiple sets of length experimental combinations for multiple types; the multiple sets of dosage experimental combinations for each type are merged and integrated with the multiple sets of length experimental combinations for multiple types to obtain the multiple sets of experimental combinations.

[0113] Furthermore, the crack prediction module 40 includes the following operation steps:

[0114] Hydration heat analysis is performed based on the performance matching doping scheme and the heat release law of concrete hydration to obtain the hydration heat temperature. Temperature accumulation calculation is performed based on the hydration heat temperature, and temperature difference calculation is performed according to the length of the long frame to obtain the temperature gradient distribution. The hydration heat temperature distribution is aligned with the external temperature positioning of each long frame to construct a temperature cloud map, which includes the temperature distribution and the temperature gradient distribution along the length and wall thickness. Based on the temperature cloud map, the temperature is converted to tensile stress using the temperature-stress relationship to obtain the temperature stress distribution in the long frame. A fusion analysis is performed based on the temperature stress distribution and the structural length characteristics to predict cracks in the long frame box culvert, and the temperature gradient crack distribution is generated according to the crack prediction probability.

[0115] Furthermore, the pouring control module 50 includes the following operating steps:

[0116] Based on the temperature gradient crack distribution and temperature stress gradient, identify the high-temperature gradient region and low-temperature gradient region in the region where the crack distribution probability reaches the threshold; based on the temperature-stress relationship of the dopant, perform dopant temperature compensation on the high-temperature gradient region and low-temperature gradient region, including compensation for the dopant ratio and / or the length of the dopant material.

[0117] Furthermore, the pouring control module 50 includes the following operating steps:

[0118] Identify nodes whose crack probability reaches a threshold from the temperature gradient crack distribution; divide the length of the long frame box culvert according to the node location to obtain the segmented interval; perform zone-by-zone and time-by-time pouring in the segmented interval; determine the temperature compensation amount based on the cumulative fitting of the hydration heat temperature of the zone-by-zone and time-by-time pouring to optimize the temperature stress gradient and obtain an optimized pouring process scheme.

[0119] Through the foregoing detailed description of the box culvert performance optimization method based on concrete doping control, those skilled in the art can clearly understand the box culvert performance optimization system based on concrete doping control in this embodiment. Since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and relevant parts can be referred to the method section.

[0120] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to 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. A method for optimizing the performance of box culverts based on the control of concrete admixture content, characterized in that, The method includes: Analyze the structural length characteristics of long frame box culverts; A correlation analysis was conducted on concrete admixtures based on the performance parameters of the box culvert, and a performance-admixture correlation list was established. The performance-doping material association list is matched and searched according to the preset performance parameter target of the long frame box culvert to obtain the performance matching doping scheme; Based on the performance matching doping scheme, length temperature stress accumulation analysis is performed according to the structural length characteristics, and crack prediction is performed according to the temperature stress gradient to obtain the temperature gradient crack distribution. Based on the temperature gradient crack distribution and temperature stress gradient, the performance matching doping scheme is optimized by compensating for the doping amount and pouring process to obtain the optimized concrete doping amount, which is used for concrete doping pouring control. Obtain the length dimensions and structural features of the long frame box culvert; Based on the length dimensions and structural characteristics, a mechanical response analysis is performed to obtain the stress characteristics of the long frame box culvert at each length, and thus obtain the structural length characteristics. The correlation analysis of concrete admixtures based on the performance parameters of the box culvert is used to establish a performance-admixture correlation list, including: Obtain the categories and names of concrete admixtures; Based on the performance parameters of the box culvert, the concrete admixtures are directionally adjusted to obtain the correlation between each type of admixture and each box culvert performance parameter; Based on the performance parameters of the box culvert, the correlation between all types of dopants and the performance parameters of the box culvert is integrated to construct the performance-dopant correlation list; Based on the performance-matching doping scheme, length-temperature stress accumulation analysis is performed according to the structural length characteristics. Crack prediction is then performed based on the temperature stress gradient to obtain the temperature gradient crack distribution, including: Based on the performance matching doping scheme and the heat release law of concrete hydration heat, hydration heat analysis was performed to obtain the hydration heat temperature. Temperature accumulation is calculated based on the hydration heat temperature, and temperature difference is calculated according to the length of the long frame to obtain the temperature gradient distribution; The hydration heat temperature distribution is aligned with the external temperature of each long frame to construct a temperature cloud map, which includes the temperature distribution and the temperature gradient distribution along the length direction and the temperature gradient distribution along the wall thickness direction. Based on the temperature cloud map, the temperature is converted into tensile stress using the temperature-stress relationship to obtain the temperature stress distribution in the long frame. Based on the fusion analysis of the temperature stress distribution and the structural length characteristics, crack prediction is performed on the long frame box culvert, and the temperature gradient crack distribution is generated according to the crack prediction probability.

2. The method for optimizing the performance of box culverts based on concrete admixture control according to claim 1, characterized in that, The performance parameters of the box culvert include: compressive strength, tensile strength, elastic modulus, impermeability, and durability.

3. The method for optimizing the performance of box culverts based on concrete admixture control according to claim 1, characterized in that, include: Multiple experimental combinations were configured based on the types of concrete admixtures; Adiabatic temperature rise experiments were conducted on the various experimental combinations to analyze the heat release law of concrete hydration heat. Based on the heat release law of concrete hydration, and combined with the external ambient temperature, a coupled temperature field and stress field experimental analysis was conducted to establish the temperature-stress relationship.

4. The method for optimizing the performance of box culverts based on concrete admixture control according to claim 3, characterized in that, Multiple experimental combinations were configured based on the types of concrete admixtures, including: For each type of concrete admixture, different dosage gradients were configured to construct multiple sets of dosage experiments for each category; Based on the various categories of multiple doping experiment combinations, different lengths of dopants are configured according to the material length of each category to construct multiple categories of multiple length experiment combinations; The multiple sets of dosage test combinations of each category and the multiple sets of length test combinations of each category are merged and integrated to obtain the multiple sets of test combinations.

5. The method for optimizing the performance of box culverts based on concrete admixture control according to claim 1, characterized in that, Based on the temperature gradient crack distribution and temperature stress gradient, the performance-matching doping scheme is optimized by compensating for the doping amount and pouring process, resulting in an optimized concrete doping amount, including: Based on the temperature gradient crack distribution and temperature stress gradient, identify the high temperature gradient region and low temperature gradient region in the region where the crack distribution probability reaches the threshold. Based on the temperature-stress relationship of the dopant, temperature compensation is performed on the high-temperature gradient region and the low-temperature gradient region, including compensation for the dopant ratio and / or the length of the dopant material.

6. The method for optimizing the performance of box culverts based on concrete admixture control according to claim 5, characterized in that, The optimized concrete doping amount is obtained by optimizing the doping scheme based on the doping amount and pouring process, and further includes: Identify nodes whose crack probability reaches a threshold from the temperature gradient crack distribution; The length of the long frame box culvert is divided according to the location of the nodes to obtain the segmented intervals; The segmented intervals are divided into zones and timed irrigations. Based on the cumulative fitting of the hydration heat temperature of the zoned and timed irrigations, the temperature compensation amount is determined to optimize the temperature stress gradient, thereby obtaining an optimized pouring process scheme.

7. A box culvert performance optimization system based on concrete admixture control, characterized in that, The system is used to implement the box culvert performance optimization method based on concrete admixture control as described in any one of claims 1-6. include: The length feature analysis module is used to analyze the structural length characteristics of long frame box culverts; The correlation analysis module is used to perform correlation analysis on concrete admixtures according to the performance parameters of the box culvert and to establish a performance-admixture correlation list. The matching search module is used to match and search the performance-dopant association list according to the preset performance parameter target amount of the long frame box culvert to obtain the performance matching doping scheme; The crack prediction module is used to perform length temperature stress accumulation analysis based on the performance matching doping scheme and according to the structural length characteristics, and to predict cracks based on the temperature stress gradient to obtain the temperature gradient crack distribution. The pouring control module is used to optimize the performance matching doping scheme by compensating for the doping amount and pouring process dimension based on the temperature gradient crack distribution and temperature stress gradient, so as to obtain the optimized concrete doping amount. The optimized concrete doping amount is used for concrete doping pouring control. Obtain the length dimensions and structural features of the long frame box culvert; Based on the length dimensions and structural characteristics, a mechanical response analysis is performed to obtain the stress characteristics of the long frame box culvert at each length, and thus obtain the structural length characteristics. Obtain the categories and names of concrete admixtures; perform directional control of the concrete admixtures according to the performance parameters of the box culvert, and obtain the correlation between each category of admixture and each box culvert performance parameter; Based on the performance parameters of the box culvert, the correlation between all types of dopants and the performance parameters of the box culvert is integrated to construct the performance-dopant correlation list; Based on the performance matching doping scheme and the heat release law of concrete hydration heat, hydration heat analysis was performed to obtain the hydration heat temperature. Temperature accumulation is calculated based on the heat of hydration temperature, and temperature difference is calculated according to the length of the elongated frame to obtain the temperature gradient distribution. The heat of hydration temperature distribution is aligned with the external temperature positioning of each elongated frame to construct a temperature cloud map, which includes the temperature distribution and the temperature gradient distribution in the length direction and the temperature gradient distribution in the wall thickness direction. Based on the temperature cloud map, the temperature is converted into tensile stress using the temperature-stress relationship to obtain the temperature stress distribution in the long frame; based on the temperature stress distribution and the structural length characteristics, a fusion analysis is performed to predict cracks in the long frame box culvert, and the temperature gradient crack distribution is generated according to the crack prediction probability.

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