A device and method for testing the adiabatic temperature rise of in-situ full-grade concrete

Abstract

This invention discloses a field-based adiabatic temperature rise test device and method for fully graded concrete, belonging to the technical field of concrete mechanical parameter testing. The device includes a container assembly, a temperature monitoring unit, a control unit, and a temperature control component. The container assembly includes a test area for accommodating the concrete specimen to be tested, and a reference area surrounding the test area, which is used to accommodate a concrete conditioning component. The temperature monitoring unit is disposed within the container assembly and is used to monitor the temperature of the concrete specimen and the concrete conditioning component. The control unit is signal-connected to the temperature monitoring unit and is configured to generate a control signal based on the temperature difference between the concrete specimen and the concrete conditioning component. The temperature control component is disposed on the outer periphery of the container assembly and signal-connected to the control unit, and is used to adjust the temperature of the concrete conditioning component according to the control signal. This method, using the aforementioned device, solves the technical problems of low test accuracy and difficulty in achieving the adiabatic boundary in existing technologies.

Description

Technical Field

[0001] This invention relates to the field of concrete mechanical parameter testing technology, and in particular to a field test device and method for thermal temperature rise of fully graded concrete. Background Technology

[0002] Concrete, as the main material for most buildings and infrastructure, has advantages such as high compressive strength, good durability, and strong plasticity. However, it also has disadvantages such as low tensile strength and easy cracking. Once cracks appear in concrete buildings, they will not only affect the aesthetics and functionality, but also weaken the overall structure and durability, posing a threat to the safety of the project.

[0003] Most concrete cracks originate from temperature stress. During cement hydration, concrete releases a large amount of heat, causing a significant rise in internal temperature. During the temperature rise phase, concrete in its plastic or early-hardening state has a low modulus of elasticity, resulting in relatively small compressive stress caused by thermal expansion. As the temperature drops after the peak, the modulus of elasticity increases, and the tensile stress generated by cooling shrinkage is much greater than the early compressive stress. Once this stress exceeds the tensile strength of the concrete, cracking occurs. Therefore, the adiabatic temperature rise caused by the heat of hydration is a key contributing factor to temperature cracks. Thus, accurately measuring the adiabatic temperature rise of concrete during the structural design phase is crucial for preventing cracks and ensuring project quality.

[0004] Currently, most existing methods for measuring adiabatic temperature rise employ laboratory-based cylinder testing, which typically involves filling freshly mixed concrete into an adiabatic cylinder of a specific size to monitor the temperature rise.

[0005] However, due to size limitations, the laboratory's insulated cylinder cannot accommodate large-diameter aggregates, requiring wet sieving of concrete to remove large particles. This results in discrepancies between the actual sample mix proportions and those used in engineering projects, particularly changes in cement dosage and aggregate gradation, severely impacting the authenticity and representativeness of the test results. Furthermore, the conditions for preparing concrete in the laboratory differ significantly from those on-site in engineering projects. For instance, the mixing process, material condition, and environmental conditions are difficult to simulate on-site conditions, reducing the engineering applicability of the test data. In addition, although the outer side of the test cylinder is equipped with an insulation layer and an active temperature control layer to achieve an insulating boundary, heat exchange is difficult to completely eliminate during actual operation, thus affecting the test accuracy. Summary of the Invention

[0006] The purpose of this invention is to provide an on-site test device and method for thermal insulation temperature rise of fully graded concrete, so as to solve the technical problems of low authenticity of the concrete thermal insulation temperature rise test process and poor test accuracy caused by the difficulty in fully realizing the thermal insulation boundary in the existing technology.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] On one hand, the present invention provides a field test device for the thermal temperature rise of fully graded concrete, comprising:

[0009] The container assembly includes a test area for accommodating a concrete specimen to be tested, and a reference area surrounding the test area for accommodating a concrete conditioning element;

[0010] A temperature monitoring unit is installed inside the container assembly to monitor the temperature of the concrete specimen under test and the concrete conditioning component.

[0011] A control unit is connected to the temperature monitoring unit and is configured to generate a control signal based on the temperature difference between the concrete specimen under test and the concrete conditioning component.

[0012] A temperature control component is disposed on the outer periphery of the container assembly and is signal-connected to the control unit. The temperature control component is used to adjust the temperature of the concrete adjustment component according to the control signal.

[0013] Preferably, the container component includes:

[0014] The inner cylinder, the internal space of which constitutes the test area;

[0015] The outer cylinder is coaxially sleeved outside the inner cylinder, and the reference area is formed between the inner cylinder and the outer cylinder.

[0016] Preferably, the radial cross-sections of the inner cylinder and the outer cylinder are circular or rectangular; the inner cylinder and the outer cylinder are made of wood with a thermal conductivity of less than 0.5 W / (m·K).

[0017] Preferably, the minimum internal dimension of the inner cylinder is not less than three times the maximum aggregate particle size in the concrete specimen being tested, the outer peripheral wall of the inner cylinder is provided with a first heat insulation layer, and / or the outer peripheral wall of the outer cylinder is provided with a second heat insulation layer, wherein the first heat insulation layer and the second heat insulation layer are aerogel heat insulation material layers.

[0018] Preferably, the temperature monitoring unit includes a plurality of first temperature sensors, which are at least located at the geometric center of the test area, the inner wall and outer wall of the inner cylinder, the geometric center of the reference area, and the inner wall and outer wall of the outer cylinder.

[0019] Preferably, the temperature monitoring unit includes a plurality of second temperature sensors arranged at intervals along at least one radial measuring line from the geometric center of the test area to the outer wall of the outer cylinder. The second temperature sensors are used to acquire the radial temperature gradient distribution of the concrete specimen under test.

[0020] Preferably, the temperature control component has a hollow cavity inside, and the hollow cavity is equipped with a temperature control execution unit. The hollow cavity is provided with at least one fluid inlet and at least one fluid outlet so that the circulating medium flows through the hollow cavity. The temperature control execution unit can adjust the temperature of the circulating medium flowing through the hollow cavity according to the control signal, thereby adjusting the temperature of the concrete adjustment component.

[0021] On the other hand, the present invention also provides a method for on-site adiabatic temperature rise testing of fully graded concrete, the method employing the aforementioned on-site fully graded concrete adiabatic temperature rise testing device, comprising:

[0022] Concrete is injected into the test area and the reference area of ​​the container assembly to form the concrete specimen to be tested in the test area and the concrete conditioning component in the reference area.

[0023] The temperature monitoring unit acquires the center temperature of the concrete specimen in real time. Temperature of the concrete adjusting component ;

[0024] The control unit is based on the temperature difference between the tested concrete specimen and the concrete conditioning component. A control signal is generated and the temperature control component is driven to adjust the temperature of the concrete adjustment component, thereby providing insulation conditions for the concrete specimen under test.

[0025] in, The temperature at the center of the concrete specimen being tested; The temperature of the concrete adjusting component; The temperature difference between the tested concrete specimen and the concrete adjustment piece;

[0026] Based on the temperature of the tested concrete specimen monitored under the adiabatic conditions, the adiabatic temperature rise curve of the tested concrete specimen was calculated by numerical simulation inversion method.

[0027] The numerical simulation inversion method includes: establishing a finite element model containing the tested concrete specimen and the concrete adjustment component, using the temperature of the temperature control component as the boundary condition, using the measured value of the center temperature of the tested concrete specimen as the inversion target, and solving the adiabatic temperature rise curve in reverse through an iterative algorithm.

[0028] Preferably, injecting the concrete into the test area and the reference area of ​​the container assembly respectively includes:

[0029] Pour the concrete into the bottom of the reference area to the preset height;

[0030] Subsequently, at the same rising speed, the concrete is poured synchronously into the remaining part of the reference area and the test area to the target height.

[0031] Preferably, the concrete injected into the test area is the original graded concrete of the project.

[0032] The concrete injected into the reference area is wet-screened concrete. The mix proportion of the wet-screened concrete is the same as that of the original graded concrete of the project, and the maximum aggregate particle size of the wet-screened concrete is less than a preset threshold.

[0033] The beneficial effects of this invention are:

[0034] The on-site full-gradation concrete adiabatic temperature rise testing device proposed in this invention monitors the temperature difference between the tested concrete specimen and the concrete conditioning component in real time through a temperature monitoring unit, and transmits this signal to the control unit. The control unit generates a corresponding control signal based on this temperature difference, driving the temperature control component to adjust the temperature of the concrete conditioning component, allowing the temperature of the concrete conditioning component to dynamically and in real time change according to the temperature changes of the tested concrete specimen. This proactive, follow-up temperature control strategy ensures that the boundary temperature of the tested concrete specimen remains consistent with the center temperature, effectively eliminating heat loss and improving testing accuracy. Furthermore, since the testing area does not require wet sieving to match the size of laboratory equipment, it can directly accommodate concrete samples containing large-diameter aggregates used in actual engineering projects, thus fully preserving the true mix proportions and aggregate gradations of the concrete, ensuring that the test results are highly authentic and representative of actual engineering projects. Attached Figure Description

[0035] Figure 1 This is a cross-sectional view of the on-site full-graded concrete adiabatic temperature rise test device provided in Embodiment 1 of the present invention;

[0036] Figure 2 This is a top view of the temperature control assembly provided in Embodiment 1 of the present invention when the radial cross-sections of the inner and outer cylinders are circular;

[0037] Figure 3 This is a top view of the temperature control assembly provided in Embodiment 1 of the present invention when the radial cross-sections of the inner and outer cylinders are rectangular;

[0038] Figure 4 This is a schematic diagram of the on-site full-graded concrete adiabatic temperature rise test device provided in Embodiment 1 of the present invention;

[0039] Figure 5 This is a flowchart of the on-site thermal temperature rise test method for fully graded concrete provided in Embodiment 2 of the present invention.

[0040] In the picture:

[0041] 100. The concrete specimen to be tested; 200. The concrete adjustment piece;

[0042] 1. Container assembly; 101. Test area; 102. Reference area; 11. Inner cylinder; 12. Outer cylinder; 13. First insulation layer; 14. Second insulation layer; 2. Temperature monitoring unit; 3. Control unit; 4. Temperature control assembly; 41. Fluid inlet; 42. Fluid outlet. Detailed Implementation

[0043] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0044] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0045] In the description of this invention, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0046] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0047] Example 1

[0048] See Figures 1 to 4The on-site thermal rise test device for fully graded concrete provided in this embodiment of the invention includes a container assembly 1, a temperature monitoring unit 2, a control unit 3, and a temperature control component 4. The container assembly 1 includes a test area 101 for accommodating the concrete specimen 100 to be tested, and a reference area 102 surrounding the test area 101, which is used to accommodate a concrete adjustment component 200. The temperature monitoring unit 2 is disposed within the container assembly 1 and is used to monitor the temperatures of the concrete specimen 100 and the concrete adjustment component 200. The control unit 3 is signal-connected to the temperature monitoring unit 2 and is configured to generate a control signal based on the temperature difference between the concrete specimen 100 and the concrete adjustment component 200. The temperature control component 4 is disposed on the outer periphery of the container assembly 1 and is signal-connected to the control unit 3. The temperature control component 4 is used to adjust the temperature of the concrete adjustment component 200 according to the control signal.

[0049] The on-site full-gradation concrete adiabatic temperature rise test device proposed in this invention monitors the temperature difference between the tested concrete specimen 100 and the concrete adjustment piece 200 in real time through a temperature monitoring unit 2, and transmits this signal to a control unit 3. The control unit 3 generates a corresponding control signal based on this temperature difference, driving the temperature control component 4 to adjust the temperature of the concrete adjustment piece 200, so that the temperature of the concrete adjustment piece 200 can dynamically and in real time change according to the temperature change of the tested concrete specimen 100. Through this active, follow-up temperature control strategy, the boundary temperature of the tested concrete specimen 100 is always consistent with the center temperature, effectively eliminating heat loss and improving test accuracy. Furthermore, since the test area 101 does not require wet sieving to match the size of laboratory equipment, it can directly accommodate concrete samples containing large-diameter aggregates used in actual engineering projects, thus completely preserving the true mix proportion and aggregate gradation of the concrete, ensuring that the test results have a high degree of authenticity and representativeness for actual engineering projects.

[0050] The specific structure and working principle of the on-site full-grade concrete adiabatic temperature rise test device are described in detail below.

[0051] The container assembly 1 serves as the main structure of the device, comprising an inner cylinder 11 and an outer cylinder 12. The internal space of the inner cylinder 11 forms the test area 101 for accommodating the concrete specimen 100 to be tested. The outer cylinder 12 is coaxially fitted around the outer side of the inner cylinder 11, forming an annular space between the inner cylinder 11 and the outer cylinder 12. This annular space serves as the reference area 102, accommodating the concrete adjustment component 200. The coaxial fit between the inner cylinder 11 and the outer cylinder 12 ensures that the concrete specimen 100 to be tested is uniformly surrounded by the concrete adjustment component 200 from all sides, facilitating the formation of a uniform insulating boundary.

[0052] Optionally, the radial cross-sections of the inner cylinder 11 and the outer cylinder 12 can be designed as circular or rectangular. Circular cross-sections are easier to process and distribute stress evenly; while rectangular cross-sections can make more efficient use of space and are easier to arrange temperature sensing elements.

[0053] To accommodate full-graded concrete tests in practical engineering, the dimensions of the inner cylinder 11 should be designed based on the maximum aggregate size used in the concrete specimen 100 being tested.

[0054] Specifically, the minimum internal dimension (diameter or side length) of the inner cylinder 11 should be no less than three times the maximum aggregate size of the concrete to ensure that the volume of the concrete specimen 100 being tested is sufficiently representative, avoid test deviations caused by size effects, and truly reflect the thermal properties of the fully graded concrete.

[0055] Preferably, the inner cylinder 11 and the outer cylinder 12 are made of wood with a thermal conductivity of less than 0.5 W / (m·K), such as wood planks. Wood, as a material with low thermal conductivity and high heat capacity, has greater thermal inertia than materials such as metals. This effectively slows down the transfer of external temperature fluctuations to the interior, thereby reducing the interference of the container wall itself on the internal concrete temperature field, preventing the cylinder wall from becoming an additional heat exchange channel, and helping to improve testing accuracy.

[0056] For devices with rectangular cross-sections, both the inner cylinder 11 and the outer cylinder 12 can be designed as modular structures to facilitate transportation and rapid on-site assembly. For example, the side plates of the inner cylinder 11 and the outer cylinder 12 can be assembled together using prefabricated mortise and tenon structures, connectors, or snap fasteners, so that the entire container assembly 1 can be easily installed and disassembled on-site, improving the device's on-site applicability.

[0057] Temperature monitoring unit 2 is installed inside container assembly 1 to monitor the temperature of the concrete specimen 100 and concrete conditioning component 200 in real time. To ensure the accuracy and fixation of the temperature measurement point, container assembly 1 also includes a bracket, which is fixed inside the inner cylinder 11 or outer cylinder 12 for installing and fixing temperature monitoring unit 2, preventing displacement of temperature monitoring unit 2 during concrete pouring or vibration compaction, thereby ensuring the reliability and representativeness of the acquired temperature.

[0058] Specifically, the outer peripheral wall of the inner cylinder 11 is provided with a first heat insulation layer 13, and / or the outer peripheral wall of the outer cylinder 12 is provided with a second heat insulation layer 14, thereby forming a multi-layered passive heat insulation barrier. The first heat insulation layer 13 is attached to the outer wall of the inner cylinder 11, and its main function is to minimize the risk of radial heat transfer from the tested concrete specimen 100 to the concrete adjustment member 200 in the reference area 102 through the inner cylinder wall. The second heat insulation layer 14 is provided on the outer peripheral wall of the outer cylinder 12 to block the influence of external ambient temperature fluctuations on the temperature field of the internal reference area 102 and the test area 101.

[0059] In a preferred embodiment, both the first insulation layer 13 and the second insulation layer 14 are made of aerogel insulation material. Aerogel insulation material has extremely low thermal conductivity and excellent high-temperature resistance, which can achieve thinner and lighter insulation layers while ensuring excellent insulation performance.

[0060] The temperature monitoring unit 2 includes multiple first temperature sensors, which are at least located at the geometric center of the test area 101, the inner and outer walls of the inner cylinder 11, the geometric center of the reference area 102, and the inner and outer walls of the outer cylinder 12. The sensor located at the geometric center of the test area 101 directly measures the core temperature of the concrete specimen 100 under test, representing the main value of its adiabatic temperature rise. The sensor located on the inner wall of the inner cylinder 11 monitors the boundary temperature in direct contact with the concrete specimen 100, while the sensor on its outer wall monitors the temperature of the surface in contact with the concrete adjustment component 200. Combining these two sets of data allows for the assessment of the heat flow trend through the inner cylinder 11 wall. Similarly, the sensor located at the geometric center of the reference area 102 monitors the core temperature of the concrete adjustment component 200, while the sensors on the inner and outer walls of the outer cylinder 12 monitor the temperature at the interface between the reference area 102 and the external environment. This comprehensive deployment scheme enables the control unit 3 to acquire complete temperature information of the test area 101 and the reference area 102 from the core to the boundary and from the inside to the outside. This allows for more accurate calculation of the effective temperature difference between the two areas and the generation of more reasonable control signals, ensuring the accuracy and stability of dynamic adiabatic boundary control.

[0061] In addition, the temperature monitoring unit 2 also includes multiple second temperature sensors arranged at intervals along at least one radial measuring line from the geometric center of the test area 101 to the outer wall of the outer cylinder 12. The second temperature sensors are used to acquire the radial temperature gradient distribution of the concrete specimen 100 under test. By using temperature readings at different points on the radial measuring line, the trend of heat transfer in the radial direction and the slope of temperature change can be clearly depicted.

[0062] The temperature control component 4 has a hollow cavity inside, which houses a temperature control actuator and has at least one fluid inlet 41 and at least one fluid outlet 42. Its working principle is as follows: a circulating medium (e.g., water, ethylene glycol solution, or heat transfer oil) flows into the hollow cavity through the fluid inlet 41 under external power, passes through the entire temperature control component 4, and exits from the fluid outlet 42, forming a circulation loop. The temperature control actuator can adjust the temperature of the circulating medium flowing through the hollow cavity in real time according to the control signal issued by the control unit 3. When the control unit 3 determines that heating is required, the temperature control actuator heats the circulating medium; otherwise, it may cool it or maintain its original temperature. Thus, when the circulating medium with a specific temperature flows through the hollow cavity of the temperature control component 4, which surrounds the container component 1, it undergoes efficient heat exchange with the concrete adjusting component 200 through the cavity wall, thereby precisely regulating the temperature of the concrete adjusting component 200.

[0063] In a preferred embodiment, the temperature control actuator is preferably a temperature control plate, such as a thermoelectric cooler (TEC) or a composite temperature control module integrating a heating wire and a temperature sensing element. This plate-like structure is easy to integrate with a hollow cavity, enabling a compact design.

[0064] To accommodate container components 1 of different shapes and ensure uniform temperature control, the specific structure of the temperature control component 4 can be flexibly varied. For container components 1 with a cylindrical radial cross-section, the temperature control component 4 is composed of two circular temperature control plates at the top and bottom and two arc-shaped sidewall temperature control plates. For container components 1 with a rectangular radial cross-section, the temperature control component 4 is composed of two rectangular temperature control plates at the top and bottom and four sidewall temperature control plates. This modular assembly design not only facilitates production and transportation but also enables rapid assembly and maintenance of the device on-site.

[0065] Example 2

[0066] See Figure 5 This invention also provides a method for on-site adiabatic temperature rise testing of fully graded concrete, using the on-site fully graded concrete adiabatic temperature rise testing device provided in Embodiment 1, wherein components identical or corresponding to those in Embodiment 1 are labeled with the corresponding reference numerals in Embodiment 1. The specific steps of this method are as follows:

[0067] Before conducting the test, the device is assembled. The base plate of the outer cylinder 12 is placed stably, and the bottom temperature control plate is reliably installed under the base plate to establish a stable foundation for the entire device. Next, brackets for fixing the first and second temperature sensors are installed on the base plate. Since the device preferably adopts a wooden assembly structure, this step can be quickly completed by mortise and tenon joints or connectors.

[0068] Subsequently, the first and second temperature sensors are reliably fixed on the installed bracket according to the preset measurement point positions, and the preliminary connection of all lines and system power-on test are completed to ensure that the signal transmission of temperature monitoring unit 2 is normal.

[0069] After confirming that the temperature monitoring unit 2 is working properly, install each side wall of the inner cylinder 11 in sequence, and tightly wrap the first heat insulation layer 13 around its outer peripheral wall. Then, assemble the side walls of the outer cylinder 12 around the inner cylinder 11 with the first heat insulation layer 13 installed, and similarly, install the second heat insulation layer 14 on the outer peripheral wall of the outer cylinder 12.

[0070] Finally, assemble the various temperature control modules on the top, bottom, and side walls into a complete temperature control assembly 4, wrap it around the second insulation layer 14 of the outer cylinder 12, and carefully connect the fluid inlet 41 and fluid outlet 42 pipes between all the temperature control modules to form a complete circulation loop. After assembly, a circulating medium needs to be introduced into the system for testing to confirm that all pipe connections are well sealed and that the medium flows smoothly.

[0071] Next, concrete is poured and samples are prepared. Concrete is poured into the test area 101 and the reference area 102 of the container assembly 1 to form the concrete specimen 100 to be tested in the test area 101 and the concrete adjustment piece 200 in the reference area 102.

[0072] To ensure that the concrete in test area 101 and reference area 102 have the same initial state and temperature field at the start of the test, and to reduce the initial thermal disturbance caused by different pouring sequences, the pouring process must follow a specific sequence.

[0073] Specifically, concrete is poured to the bottom of reference zone 102 to a preset height; then, at the same rising speed, concrete is simultaneously poured to the remaining part of reference zone 102 and the test zone 101 to the target height. This pouring method, which first pours concrete to form a stable base at the bottom of reference zone 102 and then pours concrete to rise synchronously in both zones, can effectively avoid the formation of dead zones at the bottom of the container that are difficult to track by temperature, and ensure that the concrete in both zones is in a similar physical environment from the beginning.

[0074] In terms of concrete selection, in order to balance the engineering authenticity of the test results with the stable and efficient operation of the temperature control system, the concrete injected into the test area 101 is preferably the original graded concrete of the project sampled directly from the project site, which includes large-diameter aggregates actually used in the project, so as to retain the true material properties of the concrete to the greatest extent.

[0075] The concrete injected into the reference area 102 can be wet-screened concrete. The mix proportion of the wet-screened concrete is exactly the same as that of the original graded concrete in the project. That is, after removing the large aggregates, the proportions of the remaining cementitious materials, fine aggregates and water remain unchanged to ensure that its basic thermal properties are highly consistent with those of the concrete in the test area 101.

[0076] Meanwhile, the maximum aggregate particle size of the wet-screened concrete is less than a preset threshold. The preset threshold is determined based on the actual size of the reference zone 102 (i.e., the width of the annular gap between the inner cylinder 11 and the outer cylinder 12) to prevent large aggregates from getting stuck in the narrow reference zone 102 or causing local uneven heat conduction. Using wet-screened concrete as the concrete conditioning component 200 ensures the similarity of the thermal properties between the concrete conditioning component 200 and the tested concrete specimen 100 in the test zone 101, laying the foundation for precise temperature tracking control. It also avoids the adverse effects that the presence of large aggregates may have on the internal temperature uniformity and heat transfer efficiency of the reference zone 102, making the adjustment of the temperature control component 4 more sensitive and effective.

[0077] After pouring is completed, the monitoring and control system is activated. The center temperature of the concrete specimen 100 being tested is acquired in real time through the temperature monitoring unit 2. Temperature of concrete adjusting component 200 The temperature is continuously transmitted to the control unit 3.

[0078] Control unit 3 is based on the temperature difference between the tested concrete specimen 100 and the concrete conditioning component 200. A control signal is generated and driven to the temperature control component 4 to adjust the temperature of the concrete adjustment component 200. The temperature control component 4 adjusts the temperature of the concrete adjustment component 200 according to the control signal, so that the concrete adjustment component 200 dynamically and in real time approaches the temperature of the concrete specimen 100 being tested, thereby providing insulation conditions for the concrete specimen 100 being tested.

[0079] in, The center temperature of the concrete specimen 100 being tested; The temperature of the concrete adjusting component is 200. The temperature difference between the tested concrete specimen 100 and the concrete conditioning piece 200;

[0080] Finally, throughout the entire test period, the temperature of the tested concrete specimen 100 monitored under adiabatic conditions was recorded and analyzed, and the adiabatic temperature rise curve of the tested concrete specimen 100 was calculated by numerical simulation inversion method.

[0081] The numerical simulation inversion method includes: establishing a finite element model containing the tested concrete specimen 100 and the concrete adjustment component 200, using the temperature of the temperature control component 4 as the boundary condition, using the measured value of the center temperature of the tested concrete specimen 100 as the inversion target, and solving the adiabatic temperature rise curve in reverse through an iterative algorithm.

[0082] The calculation method for the adiabatic temperature rise curve is explained in detail below. The core principle of adiabatic temperature rise is that, under ideal adiabatic conditions, all the heat generated by the cement hydration of the tested concrete specimen 100 is used to raise the temperature of the tested concrete specimen 100 itself, with no heat loss. Therefore, the adiabatic temperature rise value is equal to the measured temperature at the center point of the tested concrete specimen 100 minus its initial temperature.

[0083] (1) When the mix proportions of the concrete specimen 100 in the inner cylinder 11 and the concrete adjustment piece 200 in the outer cylinder 12 are consistent;

[0084] In this case, the key parameters such as concrete content and water-cement ratio are the same for the tested concrete specimen 100 and the concrete conditioning component 200, with only slight differences in aggregate particle size distribution. The adiabatic temperature rise capacity of the inner cylinder 11 and the outer cylinder 12 are considered to be the same. Therefore, the temperature history at the geometric center point of the inner cylinder 11 can be directly used as the adiabatic temperature rise curve of the tested concrete specimen 100. The calculation formula is as follows:

[0085] ;

[0086] in, The adiabatic temperature rise (°C) is expressed at time t. The measured temperature (°C) at the center point of the inner cylinder 11 at time t is given. This indicates the initial temperature of the concrete specimen 100 being tested.

[0087] Among them, the initial temperature ( The actual concrete outlet temperature was taken on site to ensure that all test parameters were derived from real data from the engineering site.

[0088] In practical applications, if the temperature monitoring results of the tested concrete specimen and the concrete adjustment piece are consistent, it indicates that the two have the same thermal properties, and the measured temperature can be directly used as the true value of the adiabatic temperature rise. If there is a difference between the two temperatures, the above-mentioned numerical simulation inversion method is required to iteratively invert the true adiabatic temperature rise curve through the finite element model in order to eliminate the error caused by material differences or heat loss.

[0089] (2) When the mix proportions of the concrete specimen 100 in the inner cylinder 11 and the concrete adjusting component 200 in the outer cylinder 12 are inconsistent, the cement content and adiabatic temperature rise potential of the concrete adjusting component 200 in the outer cylinder 12, having removed large aggregates, are usually higher than those of the concrete specimen 100 in the inner cylinder 11. Directly using the center temperature of the inner cylinder 11 will result in a deviation, which needs to be corrected. One of the following two methods can be used:

[0090] Method 1: Heat Compensation Method

[0091] Assume that the concrete specimen 100 in the inner cylinder 11 and the concrete conditioning component 200 in the outer cylinder 12 exchange heat through the first insulation layer 13. The adiabatic temperature rise is caused by two parts: the heat of hydration of the concrete specimen 100 itself and the heat obtained from the concrete conditioning component 200, as shown in the following formula:

[0092] ;

[0093] in, This represents the compensated temperature rise (°C) at time t. Its value can be determined through preliminary calibration tests, i.e., by pre-testing the difference function of the adiabatic temperature rise between the concrete adjuster 200 and the tested concrete specimen 100 under the same mix proportion. Alternatively, it can be estimated during the data processing stage using a numerical inversion algorithm based on the temperature of the outer cylinder 12 and the system's thermal parameters.

[0094] Method 2: Numerical simulation inversion method (preferred)

[0095] This is the core advantage of this invention in conjunction with numerical simulation. A precise finite element model is established, comprising the tested concrete specimen 100, the concrete adjustment component 200, the first insulation layer 13, the second insulation layer 14, and the temperature control component 4. The measured temperature of the circulating medium within the temperature control component 4 is used as the boundary condition of the model, and the measured temperature at the center point of the inner cylinder 11 is used as the boundary condition. As the inversion target, the adiabatic temperature rise curve of the tested concrete specimen 100, which uniquely matches the model's calculated value with the measured value, is derived through an iterative algorithm. This method can minimize systematic errors caused by the thermal inertia of the device and the difference between the inner and outer cylinders 12, and obtain high-precision adiabatic temperature rise data of the original stage.

[0096] The heat capacity (endothermic effect) and thermal resistance (adiabatic effect) of the scaffold and aerogel are implicitly included in the numerical simulation inversion method described above. If a simplified calculation method is used, a quantitative evaluation is required.

[0097] The heat absorbed by the device system during the heating process can be expressed by the following formula:

[0098] ;

[0099] in, The total heat absorbed by the system (including the first insulation layer 13, the support, the inner cylinder 11 and the outer cylinder 12, etc.) is expressed in J. Indicates the mass (kg) of component i (first insulation layer 13, bracket); The specific heat capacity of component i is expressed in J / (kg·K). This represents the average temperature rise (K) of component i during the test.

[0100] Total heat of hydration released by the tested concrete specimen 100 Part of it is used for self-heating (i.e., adiabatic temperature rise), and the other part is absorbed by the system. The formula for adiabatic temperature rise compensation is as follows:

[0101] ;

[0102] in, This indicates the mass (kg) of 100 of the concrete specimen being tested. This indicates the specific heat capacity of the concrete specimen 100 being tested (usually taken as 900-1000 J / (kg·K)).

[0103] In practice, the thermophysical parameters (density, specific heat capacity, and thermal conductivity) of the first insulation layer 13 and the support can be obtained from the material supplier or measured in the laboratory. During data processing, these parameters are substituted into the formula to correct the initially calculated adiabatic temperature rise curve, thereby eliminating the error caused by the heat absorption effect and obtaining an adiabatic temperature rise result that is closer to the actual situation.

[0104] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A field test device for the thermal temperature rise of fully graded concrete, characterized in that, include: The container assembly (1) includes a test area (101) for accommodating a concrete specimen (100) to be tested, and a reference area (102) surrounding the test area (101), the reference area (102) for accommodating a concrete adjuster (200); the concrete specimen (100) to be tested is the original graded concrete of the project; the concrete adjuster (200) is wet-sieved concrete, the mix proportion of the wet-sieved concrete is the same as the mix proportion of the original graded concrete of the project, and the maximum aggregate particle size of the wet-sieved concrete is less than a preset threshold. A temperature monitoring unit (2) is installed inside the container assembly (1) to monitor the temperature of the concrete specimen (100) and the concrete conditioning component (200); The control unit (3) is connected to the temperature monitoring unit (2) by signal. The control unit (3) is configured to generate a control signal based on the temperature difference between the concrete specimen (100) being tested and the concrete adjustment piece (200). Temperature control component (4) is disposed on the outer periphery of the container component (1) and is signal-connected to the control unit (3). Temperature control component (4) is used to adjust the temperature of the concrete adjustment component (200) according to the control signal.

2. The on-site full-graded concrete adiabatic temperature rise test device according to claim 1, characterized in that, The container component (1) includes: Inner cylinder (11), the internal space of which constitutes the test area (101). The outer cylinder (12) is coaxially sleeved outside the inner cylinder (11), and the reference area (102) is formed between the inner cylinder (11) and the outer cylinder (12).

3. The on-site full-graded concrete adiabatic temperature rise test device according to claim 2, characterized in that, The radial cross-section of the inner cylinder (11) and the outer cylinder (12) is circular or rectangular; the inner cylinder (11) and the outer cylinder (12) are made of wood with a thermal conductivity of less than 0.5 W / (m·K).

4. The on-site full-graded concrete adiabatic temperature rise test device according to claim 2, characterized in that, The minimum internal dimension of the inner cylinder (11) is not less than 3 times the maximum aggregate particle size in the concrete specimen (100) being tested. The outer peripheral wall of the inner cylinder (11) is provided with a first heat insulation layer (13), and / or the outer peripheral wall of the outer cylinder (12) is provided with a second heat insulation layer (14), wherein the first heat insulation layer (13) and the second heat insulation layer (14) are aerogel heat insulation material layers.

5. The on-site full-graded concrete adiabatic temperature rise test device according to claim 2, characterized in that, The temperature monitoring unit (2) includes a plurality of first temperature sensors, which are arranged at least at the geometric center of the test area (101), the inner and outer walls of the inner cylinder (11), the geometric center of the reference area (102), and the inner wall of the outer cylinder (12).

6. The on-site full-graded concrete adiabatic temperature rise test device according to claim 2, characterized in that, The temperature monitoring unit (2) includes a plurality of second temperature sensors arranged at intervals along at least one radial measuring line from the geometric center of the test area (101) to the outer side wall of the outer cylinder (12). The second temperature sensors are used to obtain the radial temperature gradient distribution of the concrete specimen (100) under test.

7. The on-site full-graded concrete adiabatic temperature rise test device according to claim 1, characterized in that, The temperature control component (4) forms a hollow cavity inside, and the hollow cavity is equipped with a temperature control execution unit. The hollow cavity is provided with at least one fluid inlet (41) and at least one fluid outlet (42) so that the circulating medium flows through the hollow cavity. The temperature control execution unit can adjust the temperature of the circulating medium flowing through the hollow cavity according to the control signal, thereby adjusting the temperature of the concrete adjustment component (200).

8. A method for on-site testing of the adiabatic temperature rise of fully graded concrete, characterized in that, The field full-graded concrete adiabatic temperature rise test device as described in any one of claims 1-7 includes: Concrete is injected into the test area (101) and the reference area (102) of the container assembly (1) respectively to form the concrete specimen (100) to be tested in the test area (101) and the concrete adjustment piece (200) to be formed in the reference area (102). The temperature monitoring unit (2) acquires the center temperature of the concrete specimen (100) in real time. Temperature of the concrete adjusting member (200) ; The control unit (3) is based on the temperature difference between the tested concrete specimen (100) and the concrete conditioning component (200). A control signal is generated and the temperature control component (4) is driven to adjust the temperature of the concrete adjustment component (200), thereby providing insulation conditions for the concrete specimen (100) under test. in, The center temperature of the concrete specimen (100) being tested; The temperature of the concrete adjusting member (200); The temperature difference between the tested concrete specimen (100) and the concrete conditioning piece (200); Based on the temperature of the tested concrete specimen (100) monitored under the adiabatic conditions, the adiabatic temperature rise curve of the tested concrete specimen (100) was calculated by numerical simulation inversion method. The numerical simulation inversion method includes: establishing a finite element model containing the tested concrete specimen (100) and the concrete adjustment component (200), using the temperature of the temperature control component (4) as the boundary condition, using the measured value of the center temperature of the tested concrete specimen (100) as the inversion target, and solving the adiabatic temperature rise curve in reverse through an iterative algorithm.

9. The on-site test method for adiabatic temperature rise of fully graded concrete according to claim 8, characterized in that, Injecting the concrete into the test area (101) and the reference area (102) of the container assembly (1) respectively includes: Pour the concrete to the bottom of the reference area (102) to the preset height; Subsequently, at the same rising speed, the concrete is poured synchronously into the remaining part of the reference area (102) and the test area (101) to the target height.

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