Temperature control anti-cracking process for mass concrete shear wall structure engineering

Abstract

The invention relates to the technical field of constructional engineering, in particular to a temperature control anti-cracking process for mass concrete shear wall structural engineering. Comprising the following steps that raw materials of concrete are optimized, and the mix proportion of the concrete is determined; a layered and segmented pouring and alternate warehouse method is adopted for construction; the intelligent temperature control system is buried, and the temperature of the concrete is monitored in real time; after concrete pouring is completed, a dynamic heat preservation and maintenance process is carried out; dynamic stress release is carried out, stress monitoring and kerf release are carried out, and an early warning system is established; post-cast strip sealing and micro-expansion compensation are conducted; through the mode, the concrete temperature is accurately monitored in real time, the temperature change conditions inside and on the surface of the concrete are mastered in time, temperature control measures are dynamically adjusted according to actual temperature data, the temperature difference inside and outside the concrete is effectively controlled, and the crack problem caused by temperature stress can be effectively prevented.

Description

Technical Field

[0001] This invention relates to the field of building engineering technology, and in particular to a temperature control and crack prevention process for large-volume concrete shear wall structures. Background Technology

[0002] In the field of building construction, large-volume concrete shear wall structures are widely used in important building structures such as high-rise buildings, large public buildings, and underground projects. Large-volume concrete generally refers to concrete structures with a minimum cross-sectional dimension greater than 1m, characterized by thick structures, large concrete volumes, complex engineering conditions, and high construction technical requirements.

[0003] During the pouring of large-volume concrete, the cement hydration reaction releases a large amount of heat, and concrete is a poor conductor of heat, making it difficult for the heat to dissipate. This causes a rapid increase in the internal temperature of the concrete, while the surface dissipates heat relatively quickly, resulting in a significant temperature difference between the interior and surface of the concrete. The temperature stress generated by this temperature difference, along with the shrinkage stress during the hardening process, interacts and influences each other, posing a serious threat to the structural quality and safety of large-volume concrete shear walls.

[0004] Currently, in the construction of large-volume concrete shear walls, there is a lack of real-time and accurate monitoring systems for concrete temperature. Most projects rely solely on simple insulation and curing, which fails to keep track of changes in the internal and surface temperatures of the concrete in a timely manner. It is also difficult to dynamically adjust temperature control measures based on actual temperature data, resulting in an inability to effectively control the temperature difference between the inside and outside of the concrete and to effectively prevent cracking caused by temperature stress. Summary of the Invention

[0005] The purpose of this invention is to provide a temperature control and crack prevention process for large-volume concrete shear wall structures. This aims to solve the technical problem that existing projects rely solely on simple thermal insulation and curing, which cannot timely monitor changes in the internal and surface temperatures of the concrete, make it difficult to dynamically adjust temperature control measures based on actual temperature data, and thus cannot effectively control the temperature difference between the inside and outside of the concrete, and cannot effectively prevent cracks caused by temperature stress.

[0006] To achieve the above objectives, the present invention employs a temperature control and crack prevention process for large-volume concrete shear wall structures, comprising the following steps: The raw materials for concrete are optimized, and the mix proportions of the concrete are determined. The construction method adopted was layered and segmented pouring and skip-pour method; An intelligent temperature control system is installed to monitor the temperature of the concrete in real time. After the concrete pouring is completed, dynamic thermal insulation and curing process is applied. Dynamic stress release is implemented through stress monitoring and slit release, and an early warning system is established. Perform post-cast strip sealing and micro-expansion compensation.

[0007] Among the steps, optimizing the raw materials for concrete and determining the concrete mix proportions includes: Slag silicate cement was selected, and each batch of cement delivered to the site was tested for fineness, setting time, soundness, and strength. Determine the coarse and fine aggregates. The coarse aggregate should be crushed stone with a larger particle size and good gradation. The particle size should be controlled between 5 and 31.5 mm and the mud content should not exceed 1%. The fine aggregate should be medium sand with a fineness modulus between 2.3 and 3.0 and a mud content not exceeding 3%. The alkali reactivity of the aggregates should also be tested. High-efficiency water-reducing agents and retarders are selected as admixtures, with a water reduction rate of not less than 25% and a retarding time controlled at 6~12h. Fly ash and slag powder are used as admixtures, with the fly ash grade not lower than Grade II and the slag powder grade not lower than S95. Preliminary mix proportions are calculated based on the concrete design strength grade, durability requirements, and raw material properties, using the volumetric method. Trial mix design was carried out based on the preliminary mix proportion, concrete specimens were made, and the workability indicators of the specimens, such as slump, spread, bleeding rate, and air content, as well as the mechanical properties of 7-day and 28-day compressive strength, were tested. The mix proportion was adjusted based on the trial mix results to ensure that the workability and mechanical properties of the concrete met the design requirements. By calculating the heat of hydration of concrete under different mix proportions, analyzing the temperature change pattern, and optimizing the mix proportions, the heat of hydration of concrete can be reduced.

[0008] Among the steps involving layered and segmented casting and skip-pour construction: Determine the layer thickness, and control the pouring thickness of each layer of concrete between 300 and 500 mm; Based on the structural characteristics of the shear wall and the requirements for construction joint setting, the shear wall is divided into several sections along its length. The length of each section should be controlled between 15 and 30m. The concrete is poured in layers according to the order of first pouring the bottom layer of concrete and then pouring the top layer of concrete before the bottom layer of concrete has initially set. The shear wall structure is divided into several compartments. The spacing between the compartments is determined based on calculations of concrete shrinkage stress and temperature stress, and is generally not less than 3m. Construction should be carried out according to the principle of skip-pour casting; During concrete pouring, an immersion vibrator is used for compaction. The compaction time should be until the concrete surface shows a layer of slurry and no longer settles. After each layer of concrete is poured, a finishing treatment should be carried out in a timely manner to remove surface bleeding water.

[0009] Among the construction steps following the principle of skip-pour casting: First, pour the blocks with odd numbers, and after they reach no less than 75% of the design strength, pour the blocks with even numbers. The time interval between pouring adjacent blocks shall be no less than 7 days.

[0010] Among the steps involves embedding an intelligent temperature control system and monitoring the temperature of the concrete in real time: Thermistor sensors are embedded at different depths and locations inside the concrete to measure the temperature changes of the concrete, and a data acquisition instrument is used to collect and store the data collected by the temperature sensors in real time. After the concrete is poured, the intelligent temperature control system is immediately activated to monitor the temperature of the concrete in real time. The system analyzes the collected temperature data, plots the concrete temperature change curve, and calculates the temperature difference between the inside and outside of the concrete and the rate of temperature rise. When the temperature difference between the inside and outside of the concrete exceeds 25℃ or the rate of temperature rise exceeds 2℃ / d, the system automatically issues an early warning signal to remind construction personnel to take corresponding temperature control measures.

[0011] Among the steps in the dynamic thermal insulation and curing process after the concrete pouring is completed: Polystyrene board with good thermal insulation properties is selected as the thermal insulation layer on the concrete surface, and a concrete curing agent with good film-forming properties is selected and sprayed on the concrete surface to form a dense curing film. Immediately after the concrete is poured, cover its surface with insulation material and compact it to ensure that the insulation material is in close contact with the concrete surface. Then cover the insulation material with a plastic film. Based on the changes in concrete temperature monitored by the intelligent temperature control system, the thermal insulation and curing measures are dynamically adjusted. After the concrete reaches its full strength, the insulation material is removed, and a curing agent is sprayed onto the concrete surface for curing for at least 14 days.

[0012] Among them, the step of dynamically adjusting the thermal insulation and curing measures based on the concrete temperature changes monitored by the intelligent temperature control system includes: When the internal temperature of concrete rises rapidly, the thickness of the insulation material should be increased appropriately or other insulation measures should be taken; when the internal temperature of concrete approaches its peak and begins to decline, the thickness of the insulation material should be gradually reduced to avoid the concrete surface temperature from dropping too quickly.

[0013] Among the steps involved in dynamic stress release, including stress monitoring and slit release, and establishing an early warning system: Fiber grating stress sensors are embedded in stress concentration areas inside concrete, including the inside and outside corners of shear walls and the locations of restrained edge components; The system collects, stores, and analyzes data from stress sensors in real time, plots concrete stress change curves, calculates the rate of stress change, and automatically issues an early warning signal when the concrete stress approaches or exceeds its tensile strength. Based on the stress monitoring results, when the concrete stress reaches a certain level, the timing of cutting the joint is determined, and the location of the joint is determined according to the structural characteristics and stress distribution of the shear wall. When using a concrete cutter for slit construction, the cutting line should be straight and the slit depth should be uniform. After the slit is completed, the debris inside the slit should be cleaned in time and the slit should be filled with elastic sealant.

[0014] Among them, in the steps of sealing the post-cast strip and compensating for micro-expansion: Based on the structural characteristics and construction requirements of the shear wall, the location of the post-cast strip is determined. The post-cast strip is generally placed in the part of the structure with less stress, including the middle of beams and slabs. The width of the post-cast strip should not be less than 800mm. The closing time of the post-cast strip should be determined based on the shrinkage and temperature changes of the concrete. Generally, the closing time of the post-cast strip should not be less than 60 days. Use reliable UEA expansion agent, with a dosage of 8% to 12% of the cement content; Before sealing the post-cast strip, clean the debris inside the post-cast strip, roughen the contact surface, rinse it with water and keep it moist. Apply an interface agent to the concrete surface on both sides of the post-cast strip, and use micro-expansion concrete with a strength grade one level higher than that of the concrete on both sides for pouring. During pouring, it should be vibrated and compacted in layers.

[0015] This invention discloses a temperature control and crack prevention process for large-volume concrete shear wall structures, comprising the following steps: optimizing concrete raw materials and determining the concrete mix proportions; employing layered and segmented pouring and skip-pour construction methods; embedding an intelligent temperature control system to monitor the concrete temperature in real time; implementing dynamic thermal insulation and curing processes after concrete pouring; performing dynamic stress release through stress monitoring and joint release, and establishing an early warning system; and sealing post-pouring strips and performing micro-expansion compensation. Through these methods, real-time and accurate monitoring of concrete temperature is achieved, allowing for timely understanding of internal and surface temperature changes within the concrete. Temperature control measures are dynamically adjusted based on actual temperature data, effectively controlling the temperature difference between the inside and outside of the concrete and preventing cracks caused by temperature stress. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating the steps of the temperature control and crack prevention process for large-volume concrete shear wall structures according to the present invention.

[0018] Figure 2 This is a flowchart of steps S100 of the present invention.

[0019] Figure 3 This is a flowchart of steps S200 of the present invention.

[0020] Figure 4 This is a flowchart of steps S300 of the present invention.

[0021] Figure 5 This is a flowchart of steps S400 of the present invention.

[0022] Figure 6 This is a flowchart of steps S500 of the present invention.

[0023] Figure 7 This is a flowchart of steps S600 of the present invention. Detailed Implementation

[0024] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application.

[0025] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0026] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0027] Please see Figures 1-7 This invention provides a temperature control and crack prevention process for large-volume concrete shear wall structures, comprising the following steps: S100: Optimize the raw materials for concrete and determine the concrete mix proportions.

[0028] In this embodiment, the raw materials for concrete are optimized, and the mix proportion of concrete is determined. The specific process is as follows: S101: Slag silicate cement is selected, and each batch of cement arriving at the site is tested for fineness, setting time, soundness, and strength. S102: Determine the coarse and fine aggregates. The coarse aggregate should be crushed stone with a larger particle size and good gradation. The particle size should be controlled between 5 and 31.5 mm, and the mud content should not exceed 1%. The fine aggregate should be medium sand with a fineness modulus between 2.3 and 3.0 and a mud content not exceeding 3%. The alkali reactivity of the aggregates should also be tested. S103: High-efficiency water-reducing agent and retarder are selected as admixtures, with a water reduction rate of not less than 25% and a retarding time controlled at 6~12h; S104: Fly ash and slag powder are used as admixtures, with the fly ash grade not lower than Grade II and the slag powder grade not lower than S95. S105: Preliminary mix design: Based on the concrete design strength grade, durability requirements, and raw material properties, the preliminary mix design is calculated using the volumetric method. S106: Conduct trial mixing based on the preliminary mix proportion, prepare concrete specimens, and test the workability indicators of the specimens, including slump, spread, bleeding rate, and air content, as well as the mechanical properties of 7-day and 28-day compressive strength. Adjust the mix proportion based on the trial mixing results to ensure that the workability and mechanical properties of the concrete meet the design requirements. S107: By calculating the heat of hydration of concrete under different mix proportions, the temperature change law is analyzed, and the mix proportion is optimized to reduce the heat of hydration of concrete.

[0029] In the above process, firstly, slag silicate cement is selected, and each batch of cement arriving at the site is tested for fineness, setting time, soundness, and strength. Then, the coarse and fine aggregates are determined. The coarse aggregate is selected as crushed stone with a larger particle size and good gradation, with a particle size preferably controlled between 5 and 31.5 mm and a mud content not exceeding 1%. The fine aggregate is selected as medium sand, with a fineness modulus preferably between 2.3 and 3.0 and a mud content not exceeding 3%. The alkali reactivity of the aggregates is also tested. Next, high-efficiency water-reducing agents and retarders are selected as admixtures, with a water reduction rate of not less than 25% and a retarding time controlled between 6 and 12 hours. Finally, fly ash and slag powder are used as admixtures, with the fly ash grade not specified. For concrete below grade II, the slag powder grade should not be lower than S95. A preliminary mix proportion is calculated based on the concrete design strength grade, durability requirements, and raw material properties, using the volumetric method. Trial mixes are then conducted based on the preliminary mix proportions, concrete specimens are prepared, and the slump, spread, bleeding rate, air content, and 7-day and 28-day compressive strength are tested. The mix proportions are adjusted based on the trial mix results to ensure the concrete's workability and mechanical properties meet design requirements. Finally, the heat of hydration of concrete under different mix proportions is calculated to analyze temperature variation patterns, and the mix proportions are optimized to reduce the heat of hydration.

[0030] S200: The construction adopts layered and segmented pouring and skip-pour method.

[0031] In this embodiment, layered and segmented casting and skip-pour construction are adopted. The specific process is as follows: S201: Determine the layer thickness, and control the pouring thickness of each layer of concrete between 300 and 500 mm; S202: Based on the structural characteristics of the shear wall and the requirements for construction joint setting, the shear wall is divided into several sections along its length. The length of each section should be controlled between 15 and 30m. The concrete is poured in layers according to the order of first pouring the bottom layer of concrete and then pouring the top layer of concrete before the bottom layer of concrete has initially set. S203: Divide the shear wall structure into several blocks. The spacing between the blocks is determined based on the concrete shrinkage stress and temperature stress, and is generally not less than 3m. S204: Construction shall be carried out in accordance with the principle of skip-pour casting; S205: During concrete pouring, an immersion vibrator shall be used for compaction. The compaction time should be until the concrete surface shows a layer of slurry and no longer settles. After each layer of concrete is poured, a finishing treatment shall be carried out in a timely manner to remove surface bleeding water.

[0032] In the above process, firstly, the layer thickness is determined, with each layer of concrete poured being between 300 and 500 mm thick. Then, based on the structural characteristics of the shear wall and the requirements for construction joints, the shear wall is divided into several segments along its length, each segment preferably between 15 and 30 meters in length. The layers are poured in sequence, with the bottom layer of concrete poured first, followed by the next layer before the bottom layer has initially set. Next, the shear wall structure is divided into several sections, with the spacing between sections determined based on calculations of concrete shrinkage stress and temperature stress, generally not less than 3 meters. Then, construction is carried out according to the principle of skip-layer pouring. The odd-numbered sections are poured first, and after reaching at least 75% of the design strength, the even-numbered sections are poured, with a time interval of at least 7 days between adjacent sections. Finally, during concrete pouring, an immersion vibrator is used for compaction, with the vibration time determined by the concrete surface becoming smooth and no longer settling. After each layer of concrete is poured, a finishing treatment is performed promptly to remove surface water.

[0033] S300: An intelligent temperature control system is installed to monitor the temperature of the concrete in real time.

[0034] In this embodiment, an intelligent temperature control system is embedded to monitor the temperature of the concrete in real time. The specific process is as follows: S301: The thermal resistance sensor is embedded in the concrete at different depths and locations to measure the temperature change of the concrete, and a data acquisition instrument is used to collect and store the data collected by the temperature sensor in real time. S302: Immediately after the concrete is poured, the intelligent temperature control system is activated to monitor the temperature of the concrete in real time. S303: Analyze the collected temperature data, plot the concrete temperature change curve, and calculate the temperature difference between the inside and outside of the concrete and the temperature rise rate. When the temperature difference between the inside and outside of the concrete exceeds 25℃ or the temperature rise rate exceeds 2℃ / d, the system will automatically issue an early warning signal to remind construction personnel to take corresponding temperature control measures.

[0035] In the above process, firstly, resistance temperature detectors (RTDs) are embedded at different depths and locations inside the concrete to measure the temperature changes of the concrete, and a data acquisition device is used to collect and store the data collected by the temperature sensors in real time. Then, after the concrete is poured, the intelligent temperature control system is immediately activated to monitor the temperature of the concrete in real time. The collected temperature data is then analyzed to plot the concrete temperature change curve and calculate the temperature difference between the inside and outside of the concrete and the temperature rise rate. When the temperature difference between the inside and outside of the concrete exceeds 25℃ or the temperature rise rate exceeds 2℃ / d, the system automatically issues an early warning signal to remind the construction personnel to take corresponding temperature control measures.

[0036] S400: Dynamic thermal insulation and curing process after concrete pouring.

[0037] In this embodiment, after the concrete pouring is completed, the dynamic thermal insulation and curing process is as follows: S401: Use polystyrene board with good thermal insulation performance as the thermal insulation layer on the concrete surface, and use concrete curing agent with good film-forming properties to spray curing agent on the concrete surface to form a dense curing film. S402: Immediately after the concrete is poured, cover its surface with insulation material and compact it to ensure that the insulation material is tightly bonded to the concrete surface. Then cover the surface of the insulation material with a plastic film. S403: Dynamically adjust thermal insulation and curing measures based on concrete temperature changes monitored by the intelligent temperature control system; S404: After the concrete reaches its full strength, the insulation material shall be removed and a curing agent shall be sprayed onto the concrete surface for curing for no less than 14 days.

[0038] In the above process, firstly, polystyrene board with good thermal insulation performance is selected as the insulation layer on the concrete surface, and a concrete curing agent with good film-forming properties is selected and sprayed onto the concrete surface to form a dense curing film. Then, after the concrete is poured, insulation material is immediately covered on its surface and compacted to ensure close adhesion between the insulation material and the concrete surface. A plastic film is then placed over the insulation material. Based on the concrete temperature changes monitored by the intelligent temperature control system, the insulation and curing measures are dynamically adjusted. When the internal temperature of the concrete rises rapidly, the thickness of the insulation material is appropriately increased or other enhanced insulation measures are taken. When the internal temperature of the concrete approaches its peak and begins to decrease, the thickness of the insulation material is gradually reduced to prevent the concrete surface temperature from dropping too quickly. After the concrete reaches its strength, the insulation material is removed, and a curing agent is sprayed onto the concrete surface for curing for at least 14 days.

[0039] S500: Performs dynamic stress release through stress monitoring and slit release, and establishes an early warning system.

[0040] In this embodiment, dynamic stress release is performed through stress monitoring and slit release, and an early warning system is established. The specific process is as follows: S501: Embed fiber optic stress sensors in stress concentration areas inside concrete, including the inside and outside corners of shear walls and the location of restrained edge components; S502: Real-time acquisition, storage and analysis of data collected by stress sensors, plotting concrete stress change curves, calculating stress change rate, and automatically issuing an early warning signal when concrete stress approaches or exceeds its tensile strength. S503: Based on the stress monitoring results, when the concrete stress reaches a certain level, determine the timing of the cutting joint, and determine the location of the cutting joint based on the structural characteristics and stress distribution of the shear wall; S504: Use a concrete cutter for slit construction. When slitting, keep the cutting line straight and the slit depth uniform. After slitting is completed, clean the debris in the slit in time and fill the slit with elastic sealant.

[0041] In the above process, fiber optic stress sensors are first embedded in stress concentration areas within the concrete, including the corners of shear walls and the locations of restrained edge components. Then, the data collected by the stress sensors is acquired, stored, and analyzed in real time to plot concrete stress variation curves and calculate the rate of stress change. When the concrete stress approaches or exceeds its tensile strength, an automatic warning signal is issued. Based on the stress monitoring results, the timing of the cutting is determined when the concrete stress reaches a certain level, and the cutting location is determined according to the structural characteristics and stress distribution of the shear wall. A concrete cutting machine is used for cutting. During cutting, the cutting line should be straight and the cutting depth uniform. After cutting, debris inside the cut is promptly cleaned, and elastic sealant is filled into the cut.

[0042] S600: Perform post-cast strip sealing and micro-expansion compensation.

[0043] In this embodiment, the post-cast strip is sealed and micro-expansion compensation is performed. The specific process is as follows: S601: Determine the location of the post-cast strip according to the structural characteristics and construction requirements of the shear wall. The post-cast strip is generally set in the part of the structure with less stress, including the middle of beams and slabs. The width of the post-cast strip should not be less than 800mm. S602: Determine the closing time of the post-cast strip based on the shrinkage and temperature changes of the concrete. Generally, the closing time of the post-cast strip should not be less than 60 days. S603: Use reliable UEA expansion agent, with a dosage of 8%~12% of the cement weight; S604: Before sealing the post-cast strip, clean the debris inside the post-cast strip, roughen the contact surface, rinse it with water and keep it moist. S605: Apply an interface agent to the concrete surface on both sides of the post-cast strip, and use micro-expansion concrete with a strength grade one level higher than that of the concrete on both sides for pouring. During pouring, it should be vibrated and compacted in layers.

[0044] In the above process, firstly, based on the structural characteristics and construction requirements of the shear wall, the location of the post-cast strip is determined. The post-cast strip is generally placed in areas of lower structural stress, including the middle of beams and slabs, and its width should not be less than 800mm. Then, based on concrete shrinkage and temperature changes, the sealing time of the post-cast strip is determined. Generally, the sealing time should not be less than 60 days. Next, a reliable UEA expansive agent is selected, with a dosage of 8%~12% of the cement weight. Before sealing the post-cast strip, debris inside the strip is cleaned, the contact surface is roughened, rinsed with water, and kept moist. An interface agent is applied to the concrete surfaces on both sides of the post-cast strip, and micro-expansion concrete with a strength grade one level higher than the concrete on both sides is used for pouring. During pouring, it should be vibrated and compacted in layers.

[0045] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein.

[0046] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A temperature control and crack prevention process for mass concrete shear wall structure engineering, characterized in that, The method comprises the following steps: Optimizing raw materials of the concrete and determining the mix proportion of the concrete; Adopting layer-by-layer and section-by-section pouring and skip-parking method for construction; Burying the intelligent temperature control system and monitoring the temperature of the concrete in real time; After the pouring of the concrete is completed, a dynamic temperature maintenance and curing process is adopted; Dynamic stress release is performed, stress monitoring and joint release are performed, and a warning system is established; Post-pouring belt sealing and micro-expansion compensation are performed.

2. The temperature control and crack prevention process for mass concrete shear wall structural engineering according to claim 1, wherein, In the step of optimizing raw materials of the concrete and determining the mix proportion of the concrete: Selecting slag portland cement, and detecting the fineness, setting time, stability and strength of each batch of incoming cement; Determining coarse aggregate and fine aggregate, the coarse aggregate is selected to be gravel with large particle size and good gradation, the particle size is controlled to be 5-31.5 mm, the clay content is not more than 1%, the fine aggregate is selected to be medium sand, the fineness modulus is controlled to be 2.3-3.0, the clay content is not more than 3%, and the alkali activity of the aggregate is detected; Selecting high-efficiency water reducing agent and retarder as admixtures, the water reducing rate is not less than 25%, and the retardation time is controlled to be 6-12 hours; Selecting fly ash and slag powder as admixtures, the grade of the fly ash is not less than the second level, and the grade of the slag powder is not less than S95; Preliminary calculation of the mix proportion, according to the design strength grade of the concrete, the durability requirement and the performance of the raw materials, the preliminary mix proportion is calculated according to the volume method; According to the preliminary mix proportion, trial mixing is performed, concrete test pieces are made, and the working performance indexes of the test pieces, such as the slump, the spread, the bleeding rate and the air content, and the mechanical performance indexes, such as the 7d and 28d compressive strength, are tested, the mix proportion is adjusted according to the trial mixing result, so that the working performance and the mechanical performance of the concrete meet the design requirements; The hydration heat of the concrete under different mix proportions is calculated, the temperature change rule is analyzed, the mix proportion is optimized, and the hydration heat of the concrete is reduced.

3. The temperature control and crack prevention process for mass concrete shear wall structural works as claimed in claim 1 wherein, In the step of adopting layer-by-layer and section-by-section pouring and skip-parking method for construction: Determining the layer thickness, the pouring thickness of each layer of concrete is controlled to be 300-500 mm; According to the structural characteristics of the shear wall and the setting requirement of the construction joint, the shear wall is divided into a plurality of sections along the length direction, the length of each section is controlled to be 15-30 m, the bottom layer of concrete is poured first, and then the upper layer of concrete is poured before the bottom layer of concrete is initially set, and the layer-by-layer pouring is performed in this order; The shear wall structure is divided into a plurality of blocks, the spacing between the blocks is determined according to the concrete shrinkage stress and the temperature stress, and is generally not less than 3 m, Construction is performed according to the skip-parking pouring principle; During the pouring of the concrete, an inserted vibrator is used for vibration, the vibration time is appropriate when the concrete surface is covered with paste and does not sink any more. After the pouring of each layer of concrete is completed, surface treatment is performed in time to remove the surface bleeding.

4. The temperature control and crack prevention process for mass concrete shear wall structural works as claimed in claim 3 wherein, In the step of performing construction according to the skip-parking pouring principle: Odd-numbered blocks are poured first, and even-numbered blocks are poured after the design strength of 75% is reached, and the interval between the pouring of adjacent blocks is not less than 7 days.

5. The temperature control and crack prevention process for mass concrete shear wall structural works as claimed in claim 1 wherein, In the step of burying the intelligent temperature control system and monitoring the temperature of the concrete in real time: The thermal resistance sensor is embedded in the concrete at different depths and positions to measure the temperature change of the concrete, and a data acquisition instrument is used to collect and store the data collected by the temperature sensor in real time. After the concrete is poured, the intelligent temperature control system is started immediately to monitor the temperature of the concrete in real time. The collected temperature data is analyzed, the temperature change curve of the concrete is drawn, and the internal and external temperature difference and temperature rise rate of the concrete are calculated. When the internal and external temperature difference of the concrete exceeds 25℃ or the temperature rise rate exceeds 2℃ / d, the system automatically sends a warning signal to remind the construction personnel to take appropriate temperature control measures.

6. The temperature control and crack prevention process for mass concrete shear wall structural works as claimed in claim 1 wherein, After the concrete is poured, the steps of the dynamic thermal insulation and curing process are as follows: Select a polyphenyl plate with good thermal insulation performance as the thermal insulation layer on the surface of the concrete, and select a concrete curing agent with good film-forming performance to spray the curing agent on the surface of the concrete to form a dense curing film. After the concrete is poured, cover the thermal insulation material on the surface of the concrete and compact it to tightly adhere the thermal insulation material to the surface of the concrete, and cover plastic film on the surface of the thermal insulation material. According to the temperature change of the concrete monitored by the intelligent temperature control system, the thermal insulation and curing measures are dynamically adjusted. After the strength of the concrete reaches the strength, the thermal insulation material is removed, and the curing agent is continuously sprayed on the surface of the concrete for curing, and the curing time is not less than 14d.

7. The temperature control and crack prevention process for mass concrete shear wall structural works as claimed in claim 6 wherein, In the step of dynamically adjusting the thermal insulation and curing measures according to the temperature change of the concrete monitored by the intelligent temperature control system: When the internal temperature of the concrete rises rapidly, the thickness of the thermal insulation material is appropriately increased or other thermal insulation measures are taken; when the internal temperature of the concrete approaches the peak value and begins to decline, the thickness of the thermal insulation material is gradually reduced to avoid the surface temperature of the concrete from falling too fast.

8. The temperature control and crack prevention process for mass concrete shear wall structural works as claimed in claim 1 wherein, In the step of dynamically releasing stress, monitoring stress and releasing joints, and establishing a warning system: The fiber grating stress sensor is embedded in the stress concentration position of the concrete, including the inside and outside corners of the shear wall and the position of the restrained edge member. The data collected by the stress sensor is collected, stored and analyzed in real time, the stress change curve of the concrete is drawn, and the stress change rate is calculated. When the stress of the concrete approaches or exceeds its tensile strength, an automatic warning signal is sent. According to the stress monitoring results, when the stress of the concrete reaches a certain degree, the joint time is determined, and according to the structure characteristics and stress distribution of the shear wall, the joint position is determined. The concrete cutting machine is used for joint construction. The cutting line should be straight and the joint depth should be uniform. After the joint is completed, the debris in the joint is cleaned in time, and the elastic sealing material is filled in the joint.

9. The temperature control and crack prevention process for mass concrete shear wall structural works as claimed in claim 1 wherein, In the step of closing the post-cast strip and compensating for micro-expansion: According to the structure characteristics and construction requirements of the shear wall, the position of the post-cast strip is determined. The post-cast strip is generally set at a position where the structure is less stressed, including the middle part of the beam and the plate. The width of the post-cast strip should not be less than 800mm. According to the shrinkage and temperature change of the concrete, the closing time of the post-cast strip is determined. Generally, the closing time of the post-cast strip should not be less than 60d. Select a reliable UEA expander with a dosage of 8%~12% of the cement dosage. Before the post-pouring belt is closed, the sundries in the post-pouring belt are cleaned, the contact surface is roughened, and the post-pouring belt is washed and kept wet; The interface agent is brushed on the concrete surface on both sides of the post-pouring belt, and the micro-expanding concrete with one higher strength grade than the concrete on both sides is poured, and the pouring should be layered and vibrated to be dense.

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