A dual circuit concrete curing system, a concrete curing method

Abstract

This invention relates to the field of winter concrete curing technology in tidal zones, and particularly to a dual-loop concrete curing system and method. The curing system includes: an external insulation layer, an outer ring pipeline and a first circulation component (for hot water), an inner ring pipeline and a second circulation component (for cold water), and a tidal adaptive control component comprising a water level sensor, an electrically controlled valve, and an intelligent control system. This system effectively reduces the temperature difference between the inside and outside of the structure through coordinated temperature control via an "inner cooling and outer insulation" dual-loop system, preventing temperature cracks. The outer ring pipeline is arranged asymmetrically with denser pipes on the water-facing side and sparser pipes on the back side, while the inner ring pipeline is arranged vertically with denser pipes in the middle and sparser pipes at both ends, conforming to the spatial distribution of hydration heat in large-volume concrete and avoiding excessive cooling in non-core areas. The intelligent control system automatically cuts off the outer ring heating supply to the seawater-immersed elevation area based on real-time tide levels, achieving precise heat compensation on demand while reducing curing energy consumption and improving the durability and safety of marine structures.

Description

Technical Field

[0001] This invention relates to the field of winter concrete curing technology in tidal zones, and particularly to a dual-circuit concrete curing system and a concrete curing method. Background Technology

[0002] In port and coastal engineering, large-volume concrete structures (such as gravity wharf breast walls and caissons) face severe temperature control challenges during winter construction. In the initial stages of large-volume concrete pouring, the concentrated release of internal hydration heat causes a rapid rise in core temperature; conversely, in the frigid winter environment, the concrete surface dissipates heat extremely quickly. The combination of high internal temperature and extreme external cold easily generates significant internal and external temperature differences and thermal stress. When this stress exceeds the early tensile strength of the concrete, it can induce penetrating or surface cracks, severely impacting the durability and safety of the hydraulic structure.

[0003] To control the temperature difference between the inside and outside of the concrete, existing technologies have developed a curing method that combines internally embedded water pipes for cooling with external insulation. For example, Chinese invention patent CN103526761A discloses an automatic temperature control and curing device and method for large-volume concrete. Its main technical means is to uniformly distribute cooling water pipes inside the concrete for internal cooling and uniformly distribute insulating water pipes on the concrete surface for surface heating and insulation, thereby reducing the temperature difference between the inside and outside of the concrete.

[0004] While the aforementioned "internal cold water circulation and external hot water circulation" solution has achieved some success in conventional large-volume concrete construction on land, it still reveals certain limitations and technical deficiencies when used for the curing of marine concrete in winter tidal zones.

[0005] First, the heat dissipation boundary of marine structures in tidal zones is complex and asymmetrical. The submerged area below the concrete is periodically immersed in seawater, which has a high specific heat capacity and a relatively stable temperature in winter; while the upper splash zone is completely exposed to severe cold winds, resulting in extremely rapid heat loss. Existing concrete curing technology cannot sense and adapt to changes in tidal levels. When the tide rises and submerges the lower part of the concrete, the heating pipes continue to blindly supply heat to the submerged area, resulting in a large amount of high-grade heat energy being directly lost to the seawater, causing energy waste. At the same time, due to the uniform distribution of pipes, areas that are severely frozen and urgently need heat compensation do not receive sufficient heat compensation, making them prone to localized frost damage and cracking.

[0006] Second, existing technologies often use uniformly distributed cooling pipes within the concrete at fixed intervals. However, the accumulation of heat from concrete hydration exhibits a typical gradient distribution, with high heat in the core area and a rapid decrease towards the edges. Uniformly distributed cooling pipes lack focus and, in winter, can even lead to over-cooling of non-core areas that are already at a low temperature. This artificially widens the local temperature gradient between the core and non-core areas, inducing latent internal stresses. Summary of the Invention

[0007] The purpose of this invention is to overcome the problem of excessive internal and external temperature differences during concrete curing in tidal zones during winter, which leads to energy waste due to tidal seawater immersion, and to provide a dual-circuit concrete curing system and concrete curing method.

[0008] In a first aspect, the present invention provides a dual-loop concrete curing system, comprising: The external insulation layer is installed in the outer ring area of ​​the concrete. The outer ring of pipes is arranged in multiple vertical layers inside the outer insulation layer and circumferentially wrapped around the concrete. The first circulation component is connected to the outer ring pipeline to form a first closed loop, which is used to heat the water in the outer ring pipeline and drive the hot water to circulate in the first closed loop. The inner ring of pipes is arranged vertically in multiple layers inside the concrete. The second circulation component is connected to the inner ring pipeline to form a second closed loop, which is used to drive the water flow to circulate within the second closed loop. The tidal adaptive control component includes electrically controlled switching valves installed at the water inlet of the outer ring pipeline in each layer, a water level sensor for real-time acquisition of tidal data, and an intelligent control system connected to all the electrically controlled switching valves and the water level sensor. The horizontal pipe spacing of the outer ring pipeline in the water-facing area of ​​the concrete is smaller than that in the back-water-facing area. The inner ring pipeline is arranged in a gradient pattern in the vertical direction of the concrete, with denser sections in the middle and sparser sections at both ends. The intelligent control system controls the opening and closing of the electrically controlled switch valves at the corresponding elevations based on the correspondence between the tide level data collected by the water level sensor and the elevation of the outer ring pipelines in each layer.

[0009] The dual-loop concrete curing system provided by this invention uses cooling water to carry away the core hydration heat inside the concrete through the inner loop pipe, while hot water is introduced through the outer loop pipe to compensate for the heat loss from the concrete surface. This reduces the large temperature difference between the inside and outside caused by the superposition of high internal temperature and extreme external cold in winter, and reduces the risk of penetrating and surface cracks in concrete curing during winter.

[0010] Addressing the complex heat dissipation boundaries of ocean tidal zones, this system, through the linkage of a water level sensor and an electrically controlled switching valve, can automatically cut off the outer ring heating supply to areas submerged in seawater based on real-time tide levels. This prevents a significant amount of high-grade heat energy from being wasted in the seawater, reduces the overall energy consumption of long-cycle maintenance, and ensures that heat is concentrated on non-submerged exposed areas that require more heat compensation.

[0011] The outer ring of pipes adopts an asymmetrical arrangement of "dense on the water-facing side and sparse on the back side," which precisely enhances the heat compensation on the windward and wave-affected side. The inner ring of pipes adopts a vertical gradient arrangement of "dense in the middle and sparse at both ends," which better matches the spatial distribution law of high temperature in the core area of ​​hydration heat inside large-volume concrete and rapid decrease towards the edge. It concentrates the cold water pipes in the core heat area of ​​concrete hydration heat, avoiding the problem of excessive cooling in the non-core area at the edge caused by the traditional equidistant distribution of water pipes, and improving the durability and safety of the hydraulic structure.

[0012] Preferably, the inner ring pipeline includes an inlet pipe, multiple horizontal pipe layers, and a return pipe; The water inlet pipe enters from the highest point of the concrete and extends to the bottom of the concrete core area; The outlet end of the inlet pipe connects to multiple layers of horizontal pipes from bottom to top, and the water flows along a circular trajectory within each of the horizontal pipe layers. The topmost horizontal pipe layer is connected to the return water pipe and is led out from the highest point of the concrete.

[0013] The inner ring pipeline adopts a top-in, top-out arrangement, eliminating the need for perforation and connection of pipes in the steel formwork of the concrete sidewalls, thus simplifying the on-site pipeline connection process. Low-temperature cold water is delivered directly to the bottom of the hydration heat core area of ​​the large-volume concrete through the main inlet pipe. After absorbing the heat of hydration, the water temperature rises, and the upward flow direction follows the natural convection trend of hot water, improving the overall heat exchange efficiency. The return water pipe is led out from the highest point of the concrete. This hydraulic path from low to high naturally pushes the residual air inside the pipeline upward and discharges it from the highest point, ensuring the stable operation of the system over a long period of time.

[0014] Preferably, the number of horizontal pipe layers is at least three, and they are distributed symmetrically from top to bottom with respect to the vertical geometric center plane of the concrete. Along the direction away from the vertical geometric center plane, the vertical spacing between two adjacent horizontal pipe layers gradually increases, and the vertical spacing increases from 1.0m to 2.0m to 1.5m to 2.5m.

[0015] The heat of hydration in large-volume concrete exhibits a distribution pattern of "high heat in the core area and rapid attenuation towards the upper and lower surfaces." This system is symmetrically distributed with the vertical geometric center plane as the reference, and the spacing gradually increases towards both ends. This ensures that the maximum cooling pipe network density precisely covers the core heat zone with the highest temperature peak, effectively reducing the heat of hydration of the concrete. For the heat transition area extending towards the upper and lower surfaces, the spacing between adjacent pipes is gradually increased, reducing the output of cold energy to the edge areas. This overcomes the technical defect of traditional uniformly distributed cooling pipes, which can easily lead to over-cooling of the non-core areas at the edges. It prevents artificially widening the temperature gradient between the core and the edges, and reduces the structural risk of latent internal stress induced by excessive local temperature differences.

[0016] Preferably, the outer ring pipeline has a branch section in the water-facing area of ​​the concrete, and the branch section branches into at least two branch pipes, so that the pipeline layout density in the water-facing area is greater than that in the backwater area.

[0017] Offshore structures in tidal zones are typically exposed to cold winds and directly subjected to the scouring and spraying of icy waves, resulting in faster heat loss. By designing branch sections to form multiple parallel branch pipes, the heating density in the waterfront area is locally amplified. This precisely and centrally resists the rapid heat loss caused by contact with seawater in winter, effectively reducing the risk of temperature difference cracks caused by localized overcooling. While ensuring the freeze protection safety of key areas, it also saves on the overall amount of pipe material and reduces the operating load of the system's circulating water pumps.

[0018] Preferably, the electrically controlled switching valves of the outer ring pipelines of each layer are all located in the upstream waterway of the branch section of the pipeline of that layer; the intelligent control system controls the on / off state of all branch pipes in the branch section of that layer by opening and closing the electrically controlled switching valves of a single layer.

[0019] When the tide level changes, the intelligent control system only needs to issue a command to a single valve at the corresponding elevation of the layer to achieve synchronous interruption or restoration of heating in all pipelines within that elevation, thereby improving the stability of system operation and reducing subsequent maintenance costs.

[0020] Preferably, in the multi-layered vertically arranged outer ring pipeline, the bottommost outer ring pipeline consists of a single pipeline in both the water-facing and back-facing areas of the concrete.

[0021] In practical engineering, the bottom of a concrete structure is usually in direct contact with the foundation or existing concrete base. The heat loss rate at this foundation contact surface is lower than that of the upper sidewalls directly exposed to cold air or seawater. If the bottom layer also uses a branched and densely packed arrangement, it may lead to excessively high local temperatures at the interface between the new and old concrete at the bottom, thereby inducing excessive temperature stress in the strongly constrained area of ​​the foundation. The asymmetrical design of retaining a single-tube structure at the bottom layer effectively avoids the risk of secondary structures induced by overheating in the foundation constrained area, and achieves refined on-demand heating for different vertical boundary conditions.

[0022] Preferably, it also includes a temperature monitoring component, which is used to collect real-time temperature data of the concrete interior and surface. The intelligent control system is connected to the temperature monitoring component, the first circulation component, and the second circulation component respectively; the intelligent control system is configured to dynamically adjust the heating power and / or circulation flow rate of the first circulation component and dynamically adjust the circulation flow rate of the second circulation component based on the acquired temperature difference data between the inside and outside of the concrete.

[0023] By collecting real-time temperature data of the interior and surface of large-volume concrete using temperature monitoring components, the limitations of traditional large-volume concrete curing, which relies on manual timed temperature measurement and has a delayed response, are solved.

[0024] The intelligent control system uses real-time acquired internal and external temperature difference data as the control variable, breaking the isolation between the internal and external circulation. When the internal and external temperature difference approaches the safety limit, the system can automatically respond by dynamically adjusting the heating power and circulation speed of the first circulation component or the cooling water flow rate of the second circulation component to promptly increase surface heat flow compensation or adjust the cooling output of the core area. When the temperature difference is within the safe range, it operates smoothly, ensuring that the internal and external temperature difference of the concrete is strictly locked within a safe range, significantly inhibiting the development of cracks. At the same time, on-demand heating and cooling also avoids excessive output and waste of heat and electricity, improving the system's economy during long curing cycles.

[0025] In a second aspect, the present invention provides a concrete curing method, characterized by employing the aforementioned dual-loop concrete curing system, comprising the following steps: S1. The intelligent control system continuously acquires the internal core temperature and surface temperature collected by the temperature monitoring component, as well as the real-time tide level data collected by the water level sensor; S2. The intelligent control system controls the second circulation component to drive cooling water circulation in the inner ring pipe to reduce the core temperature based on the internal and external temperature difference data; and controls the first circulation component to drive hot water circulation in the outer ring pipe, adjusting the heating power and / or circulation flow rate to compensate for surface heat loss. The intelligent control system compares the tide level data with the preset elevation of the outer ring pipelines of each layer in real time. When the tide rises and submerges the outer ring pipeline at the corresponding elevation, it controls the corresponding electrically controlled switch valve to close; when the tide drops below the corresponding elevation, it reopens the corresponding electrically controlled switch valve. S3. The intelligent control system calculates the equivalent age of the surface concrete based on the real-time collected surface temperature, calculates the dynamic compressive strength and dynamic tensile strength of the surface concrete based on the equivalent age, and predicts the residual thermal stress generated after the temperature is removed. When it is determined that the dynamic compressive strength is greater than the critical strength for freezing and the residual thermal stress is less than the dynamic tensile strength, the intelligent control system controls the first circulation component to gradually reduce the heat input until it eventually shuts down.

[0026] The concrete curing method provided by this invention can respond in real time to the dynamic changes in the internal and external temperature difference of large-volume concrete by continuously acquiring the core temperature and surface temperature, and precisely drive the inner cooling cycle and the outer heating cycle accordingly. This achieves automatic coupling control of "internal cooling and external protection", strictly locking the internal and external temperature difference within a safe range and significantly reducing the risk of cracking.

[0027] By dynamically comparing real-time tide level data with the absolute elevation of the outer ring heating pipes of each layer, the control valves are automatically shut off when the tide rises and submerges the corresponding pipes, thus avoiding the direct loss of a large amount of high-grade heat energy into the seawater. This overcomes the heat waste caused by the traditional heating pipes blindly and continuously supplying heat to the submerged area, and reduces the overall maintenance energy consumption.

[0028] This method abandons the traditional extensive mode of relying on manual experience to stop the machine at set times. Only when the two hard conditions of dynamic compressive strength calculated by simulation are greater than the critical strength under freezing and the predicted residual thermal stress is less than the dynamic tensile strength are met simultaneously, the system is allowed to issue a temperature control exit command, thereby improving the concrete curing effect.

[0029] This method controls the circulation components to gradually reduce heat input during decommissioning, avoiding a sudden drop in surface temperature caused by immediate shutdown, slowing down the surface heat loss rate, effectively avoiding the large residual thermal stress caused by sudden cooling, and ensuring that large-volume concrete passes through the curing period smoothly and safely.

[0030] Preferably, the effective age t of S3 e The calculation model is as follows:

[0031] Where E is the activation energy of concrete hydration, in J / mol; R is the gas constant, in J / (mol·K); T i Δt represents the surface temperature collected in the i-th measurement, in °C; Δt represents the interval between measurements of the concrete surface temperature, in hours; n represents the total number of measurements of the concrete surface temperature, dimensionless. Dynamic compressive strength f cu (t e and dynamic tensile strength f tk (t e The calculation model for ) is:

[0032]

[0033] Where a and b are the strength evolution constants of concrete, with the unit of a being h and b being a dimensionless constant; f cu,∞ The benchmark final compressive strength is expressed in MPa. Predicting the residual thermal stress σ generated after cooling th The calculation model is as follows:

[0034]

[0035] Where α is the coefficient of linear expansion of concrete, in °C. -1μ is the Poisson's ratio of concrete, dimensionless; K R S is the surface constraint coefficient, dimensionless; m ΔT is the stress relaxation coefficient, dimensionless; drop E represents the difference between the current concrete surface temperature and the lowest ambient temperature within a preset future time period, expressed in °C. c (t e E represents the dynamic elastic modulus of concrete, expressed in MPa. c,28 and f cu,28 These are the standard compressive modulus of elasticity and compressive strength at 28 days, respectively, both in MPa.

[0036] The concrete curing method provided by this invention integrates complex real-time environmental temperature fluctuations into equivalent ages, thereby scientifically quantifying the maturity of concrete under non-standard environments. Subsequently, using hyperbolic functions and evolution constants adapted to the current engineering concrete, the dynamic compressive and tensile strengths of the concrete are calculated. Finally, considering material stiffness, future thermal shock from cooling, and structural constraints, residual thermal stress is predicted in advance before the system is shut down. This method eliminates the reliance on extensive experience in traditional concrete curing and provides scientific guidance for the safe cooling of large-volume concrete.

[0037] Preferably, in S3, the intelligent control system controls the first circulation component to gradually lower the circulating water temperature according to the preset cooling steps, until the difference between the circulating water temperature in the outer ring pipe and the real-time ambient temperature is less than the preset safe temperature difference threshold, and then executes the final shutdown command.

[0038] Traditional concrete curing methods involve abruptly shutting down the power supply after a predetermined number of days, causing the concrete surface to instantly lose its heat source and be directly exposed to the extreme cold of winter, leading to surface shrinkage and significant residual tensile stress. This method, by gradually lowering the water temperature according to a preset cooling gradient, provides the concrete with a smooth physical transition period, promoting the slow outward conduction of heat from the concrete's interior to the surface, thus slowing down the rate of heat loss and preventing surface cracking caused by sudden temperature drops.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a dual-loop concrete curing system, in which cooling water is introduced through the inner loop to remove the core hydration heat inside the concrete, while hot water is introduced through the outer loop to compensate for the heat loss from the concrete surface. This reduces the large temperature difference between the inside and outside caused by the superposition of high internal temperature and extreme external cold in winter, and reduces the risk of penetrating and surface cracks in concrete curing in winter. 2. This invention provides a dual-loop concrete curing system that, through the linkage of a water level sensor and an electrically controlled switching valve, can automatically cut off the outer ring heating supply to the seawater-immersed elevation area based on real-time tide levels. This avoids the waste of a large amount of high-grade heat energy in the seawater, reduces the overall energy consumption of long-cycle curing, and ensures that heat is concentrated on non-submerged exposed areas that require more heat compensation. 3. This invention provides a dual-loop concrete curing system. The outer ring pipeline adopts an asymmetrical arrangement of "dense on the water-facing side and sparse on the back side," which precisely enhances the heat compensation of the windward and wave-affected side. The inner ring pipeline adopts a vertical gradient arrangement of "dense in the middle and sparse at both ends," which better matches the spatial distribution law of high temperature in the core area of ​​hydration heat inside large-volume concrete and rapid decrease towards the edge. It concentrates the cold water pipes in the core heat area of ​​concrete hydration heat, avoiding the problem of excessive cooling in the non-core area at the edge caused by the traditional equidistant uniform distribution of water pipes, and improving the durability and safety of hydraulic structures.

[0040] 4. This invention provides a concrete curing method that, by continuously acquiring core and surface temperatures, can respond in real-time to the dynamic changes in the internal and external temperature differences of large-volume concrete, and precisely drive the inner cooling cycle and outer heating cycle accordingly. This achieves automatic coupled control of "internal cooling and external protection," strictly locking the internal and external temperature differences within a safe range and significantly reducing the risk of cracking. Furthermore, by dynamically comparing real-time tide level data with the absolute elevation of each layer of outer heating pipes, the method automatically closes control valves when the tide rises and submerges the corresponding pipes, preventing a large amount of high-grade heat energy from being directly lost to seawater. This overcomes the problem of traditional heating pipes blindly and continuously supplying heat to submerged areas. This reduces heat waste and lowers overall curing energy consumption. It abandons the traditional, reliant method of manually shutting down systems at set times. The system only issues a temperature control exit command when both the calculated dynamic compressive strength exceeds the critical freezing strength and the predicted residual thermal stress is less than the dynamic tensile strength. This improves concrete curing effectiveness. By controlling the circulation components to gradually reduce heat input during exit, it avoids a sudden drop in surface temperature caused by immediate shutdown, slows the surface heat loss rate, effectively avoids the significant residual thermal stress caused by sudden cooling, and ensures that large-volume concrete can smoothly and safely pass through the curing period. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of a dual-loop concrete curing system.

[0042] Figure 2 This is a schematic diagram of the outer and inner pipeline layout.

[0043] Figure 3 This is a schematic diagram of the outer ring pipeline layout.

[0044] Figure 4 This is a schematic diagram of the inner pipeline layout.

[0045] Figure 5 This is a schematic diagram of the arrangement of wireless temperature sensors within a concrete cross-section.

[0046] Figure 6 This is a schematic diagram of the external insulation layer structure.

[0047] Marked in the image: 1-External insulation layer, 11-Steel formwork, 12-Insulation board, 2-Outer ring pipe, 21-Branch pipe, 3-Inner ring pipe, 31-Inlet pipe, 32-Horizontal pipe layer, 33-Return pipe, 41-Electrically controlled switch valve, 42-Water level sensor, 43-Intelligent control system, 51-Insulated water tank, 52-First water pump, 53-Heater, 54-Flow monitor, 61-Cold water tank, 62-Second water pump, 71-Wireless temperature sensor, 72-Temperature acquisition instrument. Detailed Implementation

[0048] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0049] Unless otherwise specified, the use of terms such as "upper," "lower," "left," "right," "center," "inner," and "outer" to indicate orientation or positional relationships in the description of specific embodiments of the present invention is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is typically placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0050] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," and "parallel" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, or parallel, but rather that it can be slightly tilted or have a deviation. For example, "horizontal" merely means that its direction is more horizontal relative to "vertical," not that the structure must be completely horizontal, but that it can be slightly tilted. Alternatively, it can be simplified to mean that the corresponding device / component / element, when set in a "horizontal," "vertical," "suspended," or "parallel" direction, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the present invention.

[0051] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0052] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as 2, 3, 4, 5, 6, 7, 8, or 9, and can even exceed nine.

[0053] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to common connection methods in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0054] Example 1 like Figures 1-6 As shown, this embodiment provides a dual-loop concrete curing system, which is mainly used in the construction of large-volume concrete (GB 50496-2018) in coastal engineering projects such as ports and docks or tidal river sections in cold regions (such as cold environments with monthly average temperatures as low as -6.5℃).

[0055] The dual-loop concrete curing system provided in this embodiment includes: External insulation layer 1 is installed in the outer ring area of ​​the concrete. Specifically, as follows... Figure 6 As shown, the external insulation layer 1 can specifically adopt a composite insulation structure, which includes a steel template 11 located on the outermost side to provide rigid support, and an insulation board 12 attached to the inner side of the steel template 11 (for example, insulation materials with low thermal conductivity such as polystyrene board or extruded board, with a thickness of 5cm to 10cm).

[0056] The outer ring pipe 2 (e.g., PVC pipe) is arranged in multiple vertical layers inside the outer insulation layer 1 and wraps around the concrete in a circumferential manner.

[0057] For specific details, please refer to the following: Figure 2 , Figure 3 As shown, the "multi-layer vertical arrangement" of the outer ring pipe 2 in this embodiment refers to the formation of multiple ring-shaped pipe layers when the pipe wraps around the large volume of concrete in the circumferential direction. These multiple ring-shaped pipe layers are distributed at intervals from bottom to top along the vertical height direction (i.e., the vertical direction) of the large volume of concrete.

[0058] The first circulation component is connected to the outer ring pipe 2 to form a first closed loop, which is used to heat the water in the outer ring pipe 2 and drive the hot water to circulate in the first closed loop. For specific details, please refer to the following: Figure 1 As shown, the first circulation assembly includes an insulated water tank 51, a first water pump 52, a heater 53, and a flow monitor 54, which are connected in series via pipes. To construct a complete and smooth fluid circulation path, the return end of the outer pipe 2 (as shown) Figure 1 The downflow pipe shown on the right is connected to the inlet of the insulated water tank 51; the outlet of the insulated water tank 51 is connected to the suction end of the first water pump 52; the discharge end of the first water pump 52 is connected to the inlet of the heater 53; the outlet of the heater 53 is connected to the inlet pipe of the flow monitor 54; and the outlet pipe of the flow monitor 54 is connected to the inlet of the outer ring pipe 2 (as shown on the right). Figure 1 The upper pipeline shown on the left is connected to the middle pipeline. Thus, a closed hot water circulation loop is formed as a whole: "outer ring pipeline 2 return water → insulated water tank 51 → first water pump 52 → heater 53 → flow monitor 54 → outer ring pipeline 2 inlet water".

[0059] In actual operation, the components of the first loop module work together, and their specific functional roles are as follows: Insulated water tank 51: Serves as a thermal energy buffer in the first closed-loop circuit. Due to the harsh natural environment and complex and variable heat dissipation boundary conditions in the tidal zone during winter, the introduction of insulated water tank 51 into the circuit, with a certain capacity of heat medium pre-stored, can stabilize the overall heat capacity of the system. This effectively avoids drastic fluctuations in pipeline water temperature caused by power adjustments of heater 53 or intermittent impacts from external waves, ensuring that the water temperature finally delivered to the outer ring pipeline 2 remains stable and uniform.

[0060] First water pump 52: Provides continuous power for fluid circulation within the first closed-loop circuit. In this embodiment, the first water pump 52 is preferably a variable frequency circulating water pump, whose control terminal is connected to the intelligent control system 43, and can dynamically adjust the circulation speed of hot water within the circuit according to the frequency adjustment command issued by the system.

[0061] Heater 53: Used for rapid heating or constant temperature maintenance of the circulating water flowing through it. Specifically, it can be a high-power industrial electric heating element assembly or an air source heat pump unit. It is electrically connected to the intelligent control system 43, enabling real-time response to system commands and achieving stepless voltage regulation or stepped switching of heating power.

[0062] Flow monitor 54: Preferably, a pipe-section electromagnetic flow meter is used for real-time online monitoring of the actual flow velocity and flow rate data of the circulating hot water in the loop. Its signal output terminal is connected to the intelligent control system 43, which feeds back the collected real-time flow velocity signal to provide data support for the frequency conversion adjustment of the first water pump 52 and the calculation of the overall heat input of the system.

[0063] The inner ring pipeline 3 is arranged vertically in multiple layers inside the concrete. The second circulation component is connected to the inner ring pipe 3 to form a second closed loop, which drives the water flow to circulate within the second closed loop to remove the hydration heat accumulated inside the concrete.

[0064] For specific details, please refer to the following: Figure 1 , Figure 2 As shown, the second circulation component mainly includes a cold water tank 61 and a second water pump 62. The outlet of the cold water tank 61 is connected to the inlet of the second water pump 62 via a pipeline; the outlet of the second water pump 62 is connected to the inlet side (i.e., inlet pipe 31) of the inner ring pipeline 3; the warm water, after heat exchange inside the concrete, is drawn out of the concrete body from the return side (i.e., return pipe 33) of the inner ring pipeline 3 and finally returned to the inlet of the cold water tank 61. This constitutes an independent inner ring closed-loop cooling water circulation system of "cold water tank 61 → second water pump 62 → inner ring pipeline 3 → cold water tank 61".

[0065] Regarding specific runtime configuration: The cold water tank 61 is used to store low-grade cooling water, providing a cold source for internal cooling. The second water pump 62 provides continuous fluid power for the fluid circulation within the inner cooling circuit. Furthermore, the second water pump 62 is preferably a variable frequency circulating water pump, and its control terminal is electrically connected to the intelligent control system 43. During actual construction and maintenance, the intelligent control system 43 can dynamically adjust the operating frequency of the second water pump 62 based on real-time temperature data fed back by temperature sensors arranged inside the concrete, thereby changing the circulation speed of the cooling water in the inner pipeline 3, so that the heat it carries away matches the heat released by the core area of ​​the concrete at different hydration stages, achieving "on-demand cooling".

[0066] It should be noted that, since this system is mainly used in frigid winter environments, the cooling water source in the cold water tank 61 can usually be directly sourced from low-temperature fresh water or groundwater in the natural environment, which can provide sufficient low-grade cooling capacity reserves for the system. Of course, in certain operating conditions with special requirements for cooling rate, the cold water tank 61 can also selectively be connected to external or internal auxiliary refrigeration equipment; this embodiment does not impose specific restrictions on this.

[0067] Reference Figure 1 and Figure 2 , Figure 3As shown, the maintenance system also includes a tide adaptive control component, which includes an electrically controlled switch valve 41 installed at the water inlet of each outer ring pipe 2, a water level sensor 42 for real-time acquisition of tide data, and an intelligent control system 43 connected (signal connection or electrical connection) to all electrically controlled switch valves 41 and water level sensors 42.

[0068] In this embodiment, the horizontal pipe spacing of the outer ring pipes 2 in the water-facing area of ​​the concrete is smaller than that in the backwater area (for example, the water-facing spacing can be set to 0.8m~1.2m, and the backwater spacing can be widened to 1.8m~2.5m); the inner ring pipes 3 are arranged in a gradient pattern in the vertical direction of the concrete, with denser pipes in the middle and sparser pipes at both ends; the intelligent control system 43 controls the opening and closing of the electrically controlled switch valves 41 at the corresponding elevations based on the correspondence between the tide level data collected by the water level sensor 42 and the elevation of each layer of the outer ring pipes 2. To prevent heat from being carried away by seawater, when the tide level drops below the elevation of that layer and remains stable for a period of time, the electrically controlled switch valves 41 are reopened to resume the heating and curing of the concrete in that area, while the circuit in the unsubmerged area continues to operate normally.

[0069] Regarding specific hardware configurations and connectivity: Water level sensor 42: Specifically, it can be an ultrasonic radar water level gauge or a submersible water level gauge that is resistant to seawater corrosion. It is fixedly installed at the reference point and used to input the elevation signal of the ocean tides to the system in real time, around the clock. Furthermore, in order to achieve precise calibration control, the water level sensor 42 can be arranged in layers along the height direction, and the installation elevation of each water level sensor 42 corresponds one-to-one with the elevation of the outer ring pipe 2 of each layer.

[0070] Electrically controlled switching valve 41: Specifically, a corrosion-resistant electric ball valve or solenoid valve with a protection rating of IP67 or higher can be used. The electrically controlled switching valve 41 is installed one-to-one at the starting inlet end of the outer ring pipeline 2 of each layer before the water flows into the concrete circumferential loop.

[0071] The intelligent control system 43, acting as the "brain" for hardware and software collaboration, is electrically or wirelessly connected to the control terminals of all electrically controlled switching valves 41 and the signal output terminals of the water level sensors 42. In this embodiment, the intelligent control system 43 can be implemented as an integrated control cabinet with a built-in programmable logic controller (PLC) or an industrial control computer (IPC) equipped with industrial control configuration software. Externally, it typically integrates a human-machine interface (HMI touchscreen) for on-site technicians to set initial parameters such as temperature thresholds and tide levels, and to monitor the overall system's operating status in real time. Before operation, the intelligent control system 43 inputs the absolute installation elevation of each outer ring pipeline 2 as a preset logical parameter to facilitate numerical comparison with the real-time sea level elevation fed back by the water level sensors 42.

[0072] Furthermore, such as Figure 1 , 2 As shown in Figure 4, the inner ring pipe 3 can be further subdivided into an inlet pipe 31, a multi-layer horizontal pipe layer 32, and a return pipe 33 in terms of spatial structure. The inlet pipe 31 enters from the highest point of the concrete and extends to the bottom of the core area of ​​the concrete (the area where the heat of hydration of the concrete generates the most heat, such as the geometric center of the concrete); the outlet of the inlet pipe 31 is connected to multiple horizontal pipe layers 32 from bottom to top, and the water flows along a circular trajectory in each horizontal pipe layer 32; the top horizontal pipe layer 32 is connected to the return pipe 33 and is led out from the highest point of the concrete.

[0073] The inner ring pipe 3 adopts a top-in, top-out arrangement, eliminating the need for perforation and connection on the steel formwork 11 of the concrete side wall, thus simplifying the on-site pipe network connection process. Low-temperature cold water is directly delivered to the bottom of the hydration heat core area of ​​the large-volume concrete through the main inlet pipe. After absorbing the hydration heat, the water temperature rises, and the upward flow direction follows the natural convection trend of hot water, improving the overall heat exchange efficiency. The return pipe 33 is led out from the highest point of the concrete. This hydraulic path from low to high can naturally push the residual air inside the pipe upward and discharge it from the highest point, ensuring the long-term stable operation of the system.

[0074] Furthermore, the number of horizontal pipe layers 32 is at least three, and they are distributed symmetrically vertically with respect to the vertical geometric center plane of the concrete. Along the direction away from the vertical geometric center plane (e.g.) Figure 1 , Figure 2 In the middle, the vertical spacing between two adjacent horizontal pipe layers 32 gradually increases, and the vertical spacing increases from 1.0m to 2.0m to 1.5m to 2.5m.

[0075] Specifically, refer to the following: Figure 4 Please provide a detailed explanation. Figure 4 The specific implementation details of the inner ring pipeline 3, which includes four horizontal pipeline layers 32, are clearly shown.

[0076] like Figure 4 The dashed line indicates that it represents the "vertical geometric center plane" of the entire large-volume concrete structure in the vertical direction.

[0077] In terms of physical arrangement: the two middle horizontal pipe layers 32 are tightly sandwiched on both sides of the central plane, and their vertical height from the central plane is marked as H1 (that is, the total vertical spacing between the two core pipe layers in the middle is 2×H1).

[0078] As the pipeline extends towards the outer area, the distance between the top horizontal pipeline layer 32 and the intermediate layer next to it is marked as H2; similarly, the distance between the bottom horizontal pipeline layer 32 and the intermediate layer next to it is also marked as H2.

[0079] According to the gradient arrangement principle of this embodiment, the spatial scale relationship H2>2×H1 is satisfied in the figure. In actual engineering implementation, the spacing (2×H1) of the middle dense area is strictly controlled within the range of 1.0m to 2.0m to provide the maximum cold source coverage; while the spacing (H2) of the outer sparse area is relaxed to 1.5m to 2.5m.

[0080] The heat of hydration in large-volume concrete exhibits a distribution pattern of "high heat in the core area and rapid attenuation towards the upper and lower surfaces." This system is symmetrically distributed with the vertical geometric center plane as the reference, and the spacing gradually increases towards both ends. This ensures that the maximum cooling pipe network density precisely covers the core heat zone with the highest temperature peak, effectively reducing the heat of hydration of the concrete. For the heat transition area extending towards the upper and lower surfaces, the spacing between adjacent pipes is gradually increased, reducing the output of cold energy to the edge areas. This overcomes the technical defect of traditional uniformly distributed cooling pipes, which can easily lead to over-cooling of the non-core areas at the edges. It prevents artificially widening the temperature gradient between the core and the edges, and reduces the structural risk of latent internal stress induced by excessive local temperature differences.

[0081] Furthermore, such as Figure 1 , 2 As shown in Figure 3, the outer ring pipe 2 has a branch section in the water-contact area of ​​the concrete (e.g., Figure 3 (The diagram shows a configuration with five branch sections). Each branch section branches into at least two horizontally parallel branch pipes 21, ensuring a higher pipe density in the waterfront area compared to the backwater area. The waterfront area of ​​marine structures in tidal zones is typically exposed to severe cold winds and direct scouring and spraying from icy waves, resulting in faster heat loss. By establishing multiple parallel branch pipes 21 in the branch sections, the heating density in the waterfront area is locally amplified. This precisely and centrally resists the rapid heat dissipation caused by seawater contact in winter, effectively reducing the risk of temperature difference cracks caused by localized overcooling. While ensuring freeze protection in key areas, this approach saves on overall pipe material usage and reduces the operating load on the system's circulating water pumps.

[0082] Furthermore, the electrically controlled switching valves 41 of each outer ring pipe 2 are all located in the upstream waterway of the branch section of the pipe on that layer (e.g., Figure 2 , 3The centrally controlled electric switch valve 41 is located adjacent to the main pipe above the junction; the intelligent control system 43 controls the flow of all branch pipes 21 within the bifurcation section of that layer by opening and closing the single-layer electric switch valve 41. When the tide level changes, the intelligent control system 43 only needs to issue a command to a single valve at the corresponding elevation of that layer to achieve synchronous flow interruption or restoration of heating in all pipelines within that elevation, thereby improving system stability and reducing subsequent maintenance costs.

[0083] Furthermore, such as Figure 2 , Figure 3 As shown, in the multi-layered vertically arranged outer ring pipes 2, the bottom outer ring pipe 2 consists of a single pipe in both the water-facing and back-facing areas of the concrete. Figure 3 For example, Figure 3 The system consists of five branching sections from top to bottom, with only the bottommost pipe being unbranched. In practical engineering, the bottom of the concrete structure is usually in direct contact with the foundation or existing concrete base. The heat loss rate at this foundation contact surface is lower than that of the upper sidewalls directly exposed to cold air or seawater. If the bottommost section also uses a densely branched arrangement, it could lead to excessively high local temperatures at the interface between the new and old concrete, resulting in excessive thermal stress in the strongly constrained area of ​​the foundation. The asymmetrical design of retaining a single-pipe structure at the bottom effectively avoids the risk of secondary structural damage induced by overheating in the foundation constrained area, achieving refined on-demand heating for different vertical boundary conditions.

[0084] Furthermore, such as Figure 1 , Figure 5 As shown, this embodiment also includes a temperature monitoring component, which is used to collect real-time temperature data of the concrete's interior and surface. Specifically, the temperature monitoring component mainly includes multiple sets of wireless temperature sensors 71 pre-embedded inside the concrete structure and on the concrete surface, and a temperature acquisition instrument 72 for centrally receiving data from each measuring point.

[0085] Reference Figure 5 The large-volume concrete cross-section shown is characterized by multiple sets of wireless temperature sensors 71 arrayed in a biaxially symmetrical cross shape (or interlaced grid pattern) within the concrete cross-section. Key monitoring points can cover: the geometric core area of ​​the concrete structure, the surface area 5cm from the concrete surface, the inlet and outlet of internal and external pipelines, and the external exposed environment.

[0086] Regarding data flow, each wireless temperature sensor 71 continuously transmits the collected temperature data from its measurement points via industrial-grade wireless communication protocols such as LoRa, ZigBee, or Bluetooth. The temperature acquisition instrument 72 receives the aforementioned temperature control signals through its configured wireless receiving antenna, standardizes and integrates the discrete data, and then transmits it in real time to the intelligent control system 43 via a data bus or wireless gateway. Furthermore, a wireless temperature sensor 71 can also be installed inside the insulated water tank 51 to monitor the reference energy storage temperature of the heat medium in the outer heating circuit in real time.

[0087] The intelligent control system 43 is connected to the temperature monitoring component, the first circulation component, and the second circulation component respectively; the intelligent control system 43 is configured to dynamically adjust the heating power and / or circulation flow rate of the first circulation component and dynamically adjust the circulation flow rate of the second circulation component based on the acquired temperature difference data between the inside and outside of the concrete.

[0088] By collecting real-time temperature data of the interior and surface of large-volume concrete using temperature monitoring components, the limitations of traditional large-volume concrete curing, which relies on manual timed temperature measurement and has a delayed response, are solved.

[0089] The intelligent control system 43 uses real-time acquired internal and external temperature difference data as a control variable, breaking the isolation between internal and external circulation. When the internal and external temperature difference approaches the safety limit, the system can automatically respond by dynamically adjusting the heating power and circulation speed of the first circulation component or the cooling water flow rate of the second circulation component to promptly increase surface heat flow compensation or adjust the core area cooling output. When the temperature difference is within the safe range, it operates smoothly, ensuring that the internal and external temperature difference of the concrete is strictly locked within a safe range, significantly inhibiting the development of cracks. At the same time, on-demand heating and cooling also avoids excessive output and waste of heat and electricity, improving the system's economy during long curing cycles.

[0090] The dual-loop concrete curing system provided in this embodiment uses cooling water introduced through the inner loop pipe 3 to remove the core hydration heat inside the concrete, while hot water is introduced through the outer loop pipe 2 to compensate for the heat loss from the concrete surface. This reduces the large temperature difference between the inside and outside caused by the superposition of high internal temperature and extreme external cold in winter, and reduces the risk of through-cracks and surface cracks in concrete curing during winter.

[0091] To address the complex heat dissipation boundaries of ocean tidal zones, this system, through the linkage of water level sensor 42 and electrically controlled switching valve 41, can automatically cut off the outer ring heating supply to the seawater-immersed elevation based on real-time tide levels. This prevents a large amount of high-grade heat energy from being wasted in the seawater, reduces the overall energy consumption of long-cycle maintenance, and ensures that heat is concentrated on non-submerged exposed areas that require more heat compensation.

[0092] The outer ring pipe 2 adopts an asymmetrical arrangement of "dense on the water-facing side and sparse on the back side", which precisely enhances the heat compensation of the wind-facing and wave-affected side; the inner ring pipe 3 adopts a vertical gradient arrangement of "dense in the middle and sparse at both ends", which better matches the spatial distribution law of high temperature in the core area of ​​hydration heat inside large-volume concrete and rapid decrease towards the edge. It concentrates the cold water pipes in the core heat area of ​​concrete hydration heat, avoids the problem of excessive cooling in the non-core area at the edge caused by the traditional equidistant distribution of water pipes, and improves the durability and safety of the hydraulic structure.

[0093] Example 2 This embodiment provides a concrete curing method, which is based on the dual-loop concrete curing system in Embodiment 1, and includes the following steps: S1. The intelligent control system 43 continuously acquires the internal core temperature and surface temperature collected by the temperature monitoring component, as well as the real-time tide level data collected by the water level sensor 42.

[0094] S2. The intelligent control system 43 controls the second circulation component to drive cooling water circulation in the inner ring pipe 3 to reduce the core temperature based on the internal and external temperature difference data; and controls the first circulation component to drive hot water circulation in the outer ring pipe 2, adjusting the heating power and / or circulation flow rate to compensate for the heat loss from the surface.

[0095] The intelligent control system 43 compares the tide level data with the preset elevation of the outer ring pipe 2 of each layer in real time. When the tide rises and submerges the outer ring pipe 2 at the corresponding elevation, it controls the corresponding electrically controlled switch valve 41 to close. When the tide level drops below the corresponding elevation and remains stable (for example, stable for 30 minutes), it reopens the corresponding electrically controlled switch valve 41.

[0096] S3. Intelligent control system 43 calculates the equivalent age of surface concrete based on real-time collected surface temperature, calculates the dynamic compressive strength and dynamic tensile strength of surface concrete based on the equivalent age, and predicts the residual thermal stress generated after cooling. When it is determined that the dynamic compressive strength is greater than the critical strength for freezing and the residual thermal stress is less than the dynamic tensile strength, the intelligent control system 43 controls the first circulation component to gradually reduce the heat input until it finally shuts down.

[0097] Specifically, the effective age t of S3 e The calculation model is as follows:

[0098] This computational model is based on the classical Arrhenius reaction rate equation. Where E is the activation energy of concrete hydration (a constant of 33500 J / mol), in J / mol; R is the gas constant (a constant of 8.314 J / (mol·K)), in J / (mol·K); T...i Δt represents the surface temperature collected in the i-th measurement, in °C; Δt represents the interval between measurements of the concrete surface temperature (e.g., once every 1 / 6 h), in h; n represents the total number of measurements of the concrete surface temperature, dimensionless. Dynamic compressive strength f cu (t e and dynamic tensile strength f tk (t e The calculation model for ) is:

[0099]

[0100] Dynamic compressive strength f cu (t e and dynamic tensile strength f tk (t e The calculation model is based on hyperbolic function fitting and the standard conversion relationship in the "Code for Design of Concrete Structures" (GB 50010-2010).

[0101] Where a and b are the strength evolution constants of concrete, with the unit of a being h and b being a dimensionless constant; f cu,∞ The reference final compressive strength is expressed in MPa. Specifically, before construction begins, the actual concrete mix design can be sent to a laboratory to measure the compressive strength at 3d, 7d, 14d, and 28d under standard curing conditions. Software can then be used to fit and derive the strength evolution constants a and b, and the reference final compressive strength f for this actual concrete mix design. cu,∞ And these parameters are stored as preset parameters in the memory of the intelligent control system 43. Predicting the residual thermal stress σ generated after cooling th The calculation model is as follows:

[0102]

[0103] This model is based on one-dimensional / two-dimensional boundary constraint theory, where α is the linear expansion coefficient of concrete (which can be taken as 1.0 × 10⁻⁶). -5 ℃ -1 (Unit: °C) -1 μ is the Poisson's ratio of concrete (can be taken as 0.2), dimensionless; K R , is the surface constraint coefficient (which can be 0.3~0.5, preferably 0.4 in this example), dimensionless; S m ΔT is the stress relaxation coefficient (which can be taken as 0.5~0.7, preferably 0.6 in this example), dimensionless; dropE represents the difference between the current concrete surface temperature and the lowest ambient temperature within a preset future time period (the lowest ambient temperature within the preset future time period can be obtained from the minimum forecast temperature for the next 24 hours via an external meteorological IoT interface), in °C. c (t e E represents the dynamic elastic modulus of concrete, expressed in MPa. c,28 and f cu,28 These are the baseline 28-day standard compressive modulus of elasticity and compressive strength (which can also be supported by data from previous laboratory standard tests), both in MPa.

[0104] To further illustrate the operational logic of the above mathematical model in actual engineering, a case study is conducted using specific operating parameters from a port terminal project: Preliminary laboratory fitting yielded the following parameters for the mixing ratio: a = 40h, b = 0.85, f cu,28 =40MPa, E c,28 =3.2×10 4 MPa, f cu,∞ =45MPa.

[0105] The system has been running continuously for maintenance for several days. The system's background accumulator calculates the equivalent age t at the current moment in real time using an integral formula. e =120h.

[0106] The current measured surface temperature of the concrete is 18℃. The predicted minimum temperature, obtained through a meteorological interface, is -2℃. Therefore, the maximum predicted temperature drop ΔT is calculated. drop =20℃.

[0107] t e Substituting 120h into the formula, we can obtain the dynamic compressive strength at this point:

[0108] The dynamic tensile strength is then calculated:

[0109] Calculate the dynamic elastic modulus of concrete:

[0110] The predicted residual thermal stress after cooling is:

[0111] The intelligent control system 43 compared the above calculation results: dynamic compressive strength 38.03MPa > critical strength under freezing 12MPa (usually taken as 30% of the standard design strength after 28 days, i.e., 40). 0.3 = 12MPa), and the residual thermal stress 1.87MPa < dynamic tensile strength 2.96MPa, the intelligent control system 43 controls the first cycle component to gradually reduce the heat input until it finally stops.

[0112] This method integrates complex real-time environmental temperature fluctuations into equivalent curing periods, thereby scientifically quantifying the maturity of concrete under non-standard environments. Subsequently, using hyperbolic functions and evolution constants applicable to the current engineering concrete, the dynamic compressive and tensile strengths of the concrete are calculated. Finally, considering material stiffness, future thermal shock from cooling, and structural constraints, residual thermal stress is predicted in advance before the system is shut down. This method eliminates the reliance on extensive experience in traditional concrete curing and provides scientific guidance for the safe cooling of large-volume concrete.

[0113] Furthermore, in the final cooling phase of S3, the intelligent control system 43 controls the first circulation component to gradually lower the circulating water temperature according to the preset cooling steps (for example, the system can be set to a cooling rate of 2℃ per day), until the difference between the circulating water temperature in the outer ring pipe 2 and the real-time ambient temperature is less than the preset safe temperature difference threshold (for example, set to 5℃), at which point the final shutdown command is executed.

[0114] Traditional concrete curing methods involve abruptly shutting down the power supply after a predetermined number of days, causing the concrete surface to instantly lose its heat source and be directly exposed to the extreme cold of winter, leading to surface shrinkage and significant residual tensile stress. This method, by gradually lowering the water temperature according to a preset cooling gradient, provides the concrete with a smooth physical transition period, promoting the slow outward conduction of heat from the concrete's interior to the surface, thus slowing down the rate of heat loss and preventing surface cracking caused by sudden temperature drops.

[0115] The concrete curing method provided in this embodiment can respond in real time to the dynamic changes in the internal and external temperature difference of large-volume concrete by continuously acquiring the core temperature and surface temperature. Based on this, it can precisely drive the inner cooling cycle and the outer heating cycle, realizing the automatic coupling control of "internal cooling and external protection", strictly locking the internal and external temperature difference within a safe range, and significantly reducing the risk of cracking.

[0116] By dynamically comparing real-time tide level data with the absolute elevation of the outer ring heating pipes of each layer, the control valves are automatically shut off when the tide rises and submerges the corresponding pipes, thus avoiding the direct loss of a large amount of high-grade heat energy into the seawater. This overcomes the heat waste caused by the traditional heating pipes blindly and continuously supplying heat to the submerged area, and reduces the overall maintenance energy consumption.

[0117] This method abandons the traditional extensive mode of relying on manual experience to stop the machine at set times. Only when the two hard conditions of dynamic compressive strength calculated by simulation are greater than the critical strength under freezing and the predicted residual thermal stress is less than the dynamic tensile strength are met simultaneously, the system is allowed to issue a temperature control exit command, thereby improving the concrete curing effect.

[0118] This method controls the circulation components to gradually reduce heat input during decommissioning, avoiding a sudden drop in surface temperature caused by immediate shutdown, slowing down the surface heat loss rate, effectively avoiding the large residual thermal stress caused by sudden cooling, and ensuring that large-volume concrete passes through the curing period smoothly and safely.

[0119] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dual-loop concrete curing system, characterized in that, include: External insulation layer (1) is set in the outer ring area of ​​the concrete; The outer ring pipe (2) is arranged in multiple vertical layers inside the outer insulation layer (1) and wraps around the concrete in a circumferential manner; The first circulation component is connected to the outer ring pipe (2) to form a first closed loop, which is used to heat the water in the outer ring pipe (2) and drive the hot water to circulate in the first closed loop. The inner ring pipeline (3) is arranged vertically in multiple layers inside the concrete. The second circulation component is connected to the inner ring pipe (3) to form a second closed loop, which is used to drive the water flow to circulate in the second closed loop. The tidal adaptive control component includes an electrically controlled switch valve (41) installed at the water inlet of the outer ring pipe (2) of each layer, a water level sensor (42) for real-time acquisition of tidal data, and an intelligent control system (43) connected to all the electrically controlled switch valves (41) and the water level sensor (42). Among them, the horizontal pipe spacing of the outer ring pipe (2) in the water-facing area of ​​the concrete is smaller than that in the back-water-facing area; The inner ring pipeline (3) is arranged in a gradient in the vertical direction of the concrete, with denser sections in the middle and sparser sections at both ends; The intelligent control system (43) controls the opening and closing of the electrically controlled switch valve (41) at the corresponding elevation based on the correspondence between the tide data collected by the water level sensor (42) and the elevation of the outer ring pipeline (2) of each layer.

2. The dual-loop concrete curing system according to claim 1, characterized in that, The inner ring pipeline (3) includes an inlet pipe (31), a multi-layer horizontal pipeline layer (32), and a return pipe (33). The water inlet pipe (31) is inserted from the highest point of the concrete and extends to the bottom of the concrete core area; The outlet end of the inlet pipe (31) is connected to multiple layers of horizontal pipe layers (32) from bottom to top, and the water flows along a circular trajectory within each of the horizontal pipe layers (32). The topmost horizontal pipe layer (32) is connected to the return water pipe (33) and is led out from the highest point of the concrete.

3. The dual-loop concrete curing system according to claim 2, characterized in that, The number of the horizontal pipe layers (32) is at least three, and they are distributed symmetrically from top to bottom with respect to the vertical geometric center plane of the concrete. Along the direction away from the vertical geometric center plane, the vertical spacing between two adjacent horizontal pipe layers (32) gradually increases, and the vertical spacing increases from 1.0m to 2.0m to 1.5m to 2.5m.

4. The dual-loop concrete curing system according to claim 1, characterized in that, The outer ring pipe (2) has a branch section in the water-facing area of ​​the concrete, and the branch section branches into at least two branch pipes (21) so that the pipe layout density in the water-facing area is greater than that in the back water-facing area.

5. A dual-loop concrete curing system according to claim 4, characterized in that, The electrically controlled switch valves (41) of the outer ring pipeline (2) of each layer are all located in the upstream waterway of the branch section of the pipeline of that layer; the intelligent control system (43) controls the opening and closing of all branch pipes (21) in the branch section of that layer by opening and closing the electrically controlled switch valves (41) of a single layer.

6. A dual-loop concrete curing system according to claim 4, characterized in that, In the multi-layered vertically arranged outer ring pipes (2), the bottommost outer ring pipes (2) are single pipes in both the water-facing and back-facing areas of the concrete.

7. A dual-loop concrete curing system according to claim 1, characterized in that, It also includes a temperature monitoring component, which is used to collect real-time temperature data of the concrete interior and surface. The intelligent control system (43) is connected to the temperature monitoring component, the first circulation component and the second circulation component respectively; the intelligent control system (43) is configured to: dynamically adjust the heating power and / or circulation flow rate of the first circulation component and dynamically adjust the circulation flow rate of the second circulation component according to the acquired temperature difference data between the inside and outside of the concrete.

8. A method for curing concrete, characterized in that, The dual-loop concrete curing system as described in claim 7 includes the following steps: S1. The intelligent control system (43) continuously acquires the internal core temperature and surface temperature collected by the temperature monitoring component, as well as the real-time tide data collected by the water level sensor (42); S2. The intelligent control system (43) controls the second circulation component to drive the cooling water circulation in the inner ring pipe (3) to reduce the core temperature based on the internal and external temperature difference data; and controls the first circulation component to drive the hot water circulation in the outer ring pipe (2), and adjusts the heating power and / or circulation flow rate to compensate for the heat loss of the surface. The intelligent control system (43) compares the tide level data with the preset elevation of the outer ring pipeline (2) of each layer in real time. When the tide rises and submerges the outer ring pipeline (2) at the corresponding elevation, it controls the corresponding electric control switch valve (41) to close. When the tide drops below the corresponding elevation, it reopens the corresponding electric control switch valve (41). S3. Intelligent control system (43) calculates the equivalent age of surface concrete based on real-time collected surface temperature, calculates the dynamic compressive strength and dynamic tensile strength of surface concrete based on the equivalent age, and predicts the residual thermal stress generated after cooling. When it is determined that the dynamic compressive strength is greater than the critical strength for freezing and the residual thermal stress is less than the dynamic tensile strength, the intelligent control system (43) controls the first cycle component to gradually reduce the heat input until it finally stops.

9. A concrete curing method according to claim 8, characterized in that, S3 medium effective age t e The calculation model is: Where E is the activation energy of concrete hydration, in J / mol; R is the gas constant, in J / (mol·K); T i Δt represents the surface temperature collected in the i-th measurement, in °C; Δt represents the interval between measurements of the concrete surface temperature, in hours; n represents the total number of measurements of the concrete surface temperature, dimensionless. Dynamic compressive strength f cu (t e and dynamic tensile strength f tk (t e The calculation model for ) is: Where a and b are the strength evolution constants of concrete, with the unit of a being h and b being a dimensionless constant; f cu,∞ The benchmark final compressive strength is expressed in MPa. Predicting the residual thermal stress σ generated after cooling th The calculation model is as follows: Where α is the coefficient of linear expansion of concrete, in °C. -1 μ is the Poisson's ratio of concrete, dimensionless; K R S is the surface constraint coefficient, dimensionless; m ΔT is the stress relaxation coefficient, dimensionless; drop E represents the difference between the current concrete surface temperature and the lowest ambient temperature within a preset future time period, expressed in °C. c (t e E represents the dynamic elastic modulus of concrete, expressed in MPa. c,28 and f cu,28 These are the standard compressive modulus of elasticity and compressive strength at 28 days, respectively, both in MPa.

10. A concrete curing method according to claim 8, characterized in that, In S3, the intelligent control system (43) controls the first circulation component to gradually lower the circulating water temperature according to the preset cooling steps until the difference between the circulating water temperature in the outer ring pipe (2) and the real-time ambient temperature is less than the preset safe temperature difference threshold, and then executes the final shutdown command.

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