A method for preparing and constructing anti-cracking mass concrete

Abstract

The application relates to the field of building construction and discloses a preparation and construction method of anti-cracking mass concrete, which comprises cement, fly ash, fine aggregate, coarse aggregate, water reducing agent and water; wherein the coarse aggregate is continuously-graded gravel, the fine aggregate comprises medium-coarse sand, and the cement comprises Portland cement; the preparation steps comprise the following steps: ZB1, the cement, fly ash, fine aggregate and coarse aggregate are added into a stirring device for dry mixing; ZB2, the water and water reducing agent are added into the dry-mixed material for wet mixing, so that the concrete mixture is uniform; and ZB3, the temperature of the obtained concrete mixture is controlled within a set range, and the preparation of the anti-cracking mass concrete is completed. The tensile strength and compactness of the concrete are improved, the hydration heat of the mass concrete is reduced, the temperature stress cracks are reduced, the temperature is monitored and the curing measures are dynamically adjusted in real time, the quality of the concrete is stable, the cracks caused by plastic shrinkage, temperature shrinkage, self-shrinkage and drying shrinkage are reduced, and the structural durability is improved.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, specifically to a method for preparing and constructing crack-resistant mass concrete. Background Technology

[0002] Mass concrete refers to a type of concrete structure characterized by its large minimum dimensions, high overall volume, and difficulty in rapidly dissipating internal hydration heat. It is commonly found in large foundation slabs, arch dams, bridge tower abutments, nuclear power plant structures, underground transportation hubs, and heavy equipment foundations. During the pouring and hardening process, the release of internal hydration heat is continuous and concentrated, resulting in significant changes in temperature and humidity fields over time. Therefore, this places higher demands on material composition, pouring organization, temperature control curing, and monitoring methods.

[0003] Mass concrete is widely used in construction projects, but due to its large volume and high heat of hydration, it is prone to temperature cracks and shrinkage cracks, seriously affecting the durability and safety of the structure. Currently, the industry mainly tries to alleviate cracking problems by optimizing the mix proportion, adding admixtures, and controlling the pouring temperature, but the effects are limited. As building structures develop towards larger scale and higher strength, higher requirements are placed on the crack resistance of mass concrete. Existing technologies struggle to balance ease of construction, economy, and crack resistance, especially in optimizing the control of autogenous shrinkage and reduction of heat of hydration. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for preparing and constructing crack-resistant mass concrete, thereby solving the aforementioned problems.

[0005] In a first aspect, the present invention provides the following technical solution: a method for preparing crack-resistant mass concrete, comprising materials and preparation steps:

[0006] The materials include: cement, fly ash, fine aggregate, coarse aggregate, water-reducing agent, and water;

[0007] The coarse aggregate is 5-25mm continuously graded crushed stone, the fine aggregate includes medium and coarse sand, and the cement includes silicate cement.

[0008] Its preparation steps include:

[0009] ZB1. The cement, fly ash, fine aggregate and coarse aggregate are added to the mixing device and dry-mixed.

[0010] ZB2. Add the water and water-reducing agent to the dry mix and wet mix to make the concrete mixture uniform.

[0011] ZB3. Control the outlet temperature of the obtained concrete mixture within the set range and complete the preparation of crack-resistant mass concrete.

[0012] By adopting the above technical solution, by rationally proportioning the dosage range of cement, fly ash, aggregate, water and water-reducing agent, and by combining dry mixing and wet mixing preparation methods, it is beneficial to improve the uniformity and stability of concrete mixtures.

[0013] Meanwhile, by controlling the concrete discharge temperature, the risk of temperature fluctuations in the early hardening stage of concrete can be reduced, and the development of internal and external temperature differences can be slowed down. This helps to reduce the feasibility of cracks in large-volume concrete during construction and early curing stages, and improves the crack resistance and reliability of the overall concrete structure.

[0014] Secondly, the present invention provides the following technical solution: a method for constructing crack-resistant mass concrete, the method comprising the following steps:

[0015] SG1. Measure the temperature of the prepared concrete before it is poured into the formwork, and determine whether the measured value meets the set temperature range for pouring into the formwork.

[0016] SG2. Pour the concrete into the target component area in layers according to the preset layer thickness, and vibrate and compact each layer to form a stable stacking structure.

[0017] SG3. After pouring, temperature measuring points are set up at different depths of the concrete, and the temperature distribution at each depth is determined based on real-time temperature data.

[0018] SG4. Set the insulation measure adjustment amount according to the temperature distribution change, and dynamically adjust the coverage thickness or range of the insulation layer;

[0019] SG5. During the later stages of construction, the concrete should be continuously kept warm and moistened according to the temperature change pattern.

[0020] As a further description of the above technical solution: the SG1 includes the following steps:

[0021] Set the temperature threshold used for determining the mold entry temperature;

[0022] Measure the real-time temperature of the concrete before it is poured into the formwork and compare it with the threshold value;

[0023] When the measured temperature deviates from the threshold range, the mold inlet temperature adjustment operation is triggered.

[0024] Among them, the temperature regulation of concrete entering the formwork includes adjusting the temperature of concrete entering the formwork by means of at least one of shading, spray cooling or reducing the transportation dwell time.

[0025] By adopting the above technical solution, the temperature of concrete before it is poured into the formwork can be determined in real time, and corresponding adjustment measures can be taken in time when it deviates from the set range. This can keep the concrete in a relatively stable temperature state during the pouring stage, thereby reducing the risk of early temperature difference and helping to improve the temperature control stability and crack resistance reliability of the large-volume concrete construction process.

[0026] As a further description of the above technical solution: the SG2 includes the following steps:

[0027] Set the layer pouring thickness and construct the interlayer boundaries based on that thickness;

[0028] Calculate the effective pouring range of the current layer based on the layer boundary;

[0029] Vibrate the concrete within the effective range and determine whether the vibration operation needs to be repeated based on the degree of compaction.

[0030] The layer thickness of the layered pouring is 300-500mm, the pouring speed is 30-35m³ / h, and the vibration is carried out in a row-and-column pattern with a spacing of 350-400mm. The vibrator is inserted into the lower layer 45-50mm.

[0031] By adopting the above technical solutions, the concrete can maintain a relatively uniform density during the layered pouring process, which helps to reduce the risk of cold joints between layers, improve the stability of pouring quality, and provide a basic guarantee for the overall crack resistance of the subsequent concrete.

[0032] As a further description of the above technical solution: the SG3 includes the following steps:

[0033] Set the locations of temperature measuring points at different depths;

[0034] Collect temperature data at each measuring point and calculate the temperature gradient change.

[0035] Determine whether the temperature distribution at each depth is stable based on changes in the temperature gradient.

[0036] Temperature measuring points are arranged on the concrete surface, in a shallow layer of 50–150 mm, and in a deep layer of 150–300 mm, with at least two redundant measuring points at each depth.

[0037] By adopting the above technical solution, and by arranging temperature measuring points at different depths and judging the changes in temperature gradient, it is beneficial to more accurately reflect the temperature distribution state inside and on the surface of concrete, improve the reliability of temperature monitoring results, and thus provide a basis for the implementation of subsequent temperature control and curing measures, reducing the risk of cracks caused by excessive temperature differences.

[0038] As a further description of the above technical solution: the SG4 includes the following steps:

[0039] Set the temperature deviation amount based on temperature change data;

[0040] Calculate the adjustment amount of the insulation layer based on the temperature deviation.

[0041] The coverage area or thickness of the insulation layer is adjusted according to the adjustment amount.

[0042] By adopting the above technical solutions, the insulation layer can be adjusted in a timely and appropriate manner according to actual temperature changes, so that the concrete can maintain a more stable temperature environment during curing, thereby reducing the accumulation of thermal stress caused by excessive temperature fluctuations, which helps to improve the overall temperature control effect and early crack resistance of large-volume concrete.

[0043] As a further description of the above technical solution: the SG4 also includes:

[0044] Set the maximum adjustment time for the insulation layer;

[0045] The addition or removal of insulation material is controlled according to the temperature change trend, so that the adjustment of the insulation layer is completed within the specified time.

[0046] The insulation measures include at least one insulation layer with adjustable thickness or coverage area, which can be added or removed within 30–60 minutes.

[0047] By adopting the above technical solutions, limiting the adjustment time of the insulation layer, and adding or removing insulation measures in a targeted manner based on temperature change trends, the timeliness and controllability of insulation adjustment are improved, making the temperature change during the concrete curing stage more gradual. This helps to reduce the risk of excessive local temperature difference caused by delayed temperature adjustment and improve the crack resistance stability of large-volume concrete.

[0048] As a further description of the above technical solution: the execution of SG4 is based on the following triggering conditions:

[0049] When the temperature difference between any depth and the surface exceeds a set difference value, the heat preservation adjustment is triggered.

[0050] When the temperature gradient between adjacent measuring points exceeds the preset gradient value, the heat preservation adjustment is triggered.

[0051] By adopting the above technical solution, the thermal insulation adjustment operation can be triggered in a timely manner when the internal temperature difference or local temperature gradient of the concrete increases abnormally. This makes the temperature control measures more targeted and timely, thereby helping to slow down the trend of temperature difference changes between the interior and the surface, avoid additional thermal stress caused by uneven temperature distribution, and improve the stability and crack resistance of early temperature control of large-volume concrete.

[0052] As a further description of the above technical solution: the SG5 includes the following sub-steps:

[0053] Set the duration of moisturizing maintenance;

[0054] Determine whether additional watering is needed based on the surface moisture content;

[0055] The frequency of watering is determined by monitoring surface humidity during the maintenance period;

[0056] The maintenance time is ≥14 days.

[0057] By adopting the above technical solution, the moisture status of the concrete surface can be continuously monitored over a longer period of time, and water can be added in time when needed, so that the concrete maintains a suitable humidity environment in the early hardening stage. This helps to slow down moisture evaporation, reduce the risk of drying shrinkage, improve the stability of the curing process, and further enhance the early crack resistance of large-volume concrete.

[0058] As a further description of the above technical solution: the SG5 also includes the following when it is in operation:

[0059] The temperature deviation of the structure in the later stage is calculated based on the temperature gradient obtained in SG3;

[0060] Determine whether the insulation coverage time needs to be extended based on the deviation amount;

[0061] When the deviation exceeds a set threshold, a local insulation enhancement operation is triggered to bring the final temperature gradient back to a safe range.

[0062] By adopting the above technical solutions, it is possible to monitor the temperature changes of concrete in the later stages of the wet curing phase, and to take timely measures to adjust the temperature by extending the insulation or strengthening the local insulation when the temperature deviation increases, so as to keep the temperature gradient within a reasonable range, thereby further reducing the risk of stress accumulation caused by temperature difference in the later stages and improving the stability of the overall temperature control and curing process of large-volume concrete.

[0063] This invention provides a method for preparing and constructing crack-resistant mass concrete. It has the following beneficial effects:

[0064] 1. In this invention, by optimizing the mix proportion and construction process, the tensile strength and density of concrete are significantly improved, the heat of hydration of large-volume concrete is effectively reduced, temperature stress cracks are reduced, and real-time temperature monitoring and dynamic adjustment of curing measures ensure stable concrete quality, reduce cracks caused by plastic shrinkage, temperature shrinkage, autogenous shrinkage and drying shrinkage, and improve structural durability.

[0065] 2. In this invention, by combining real-time surface humidity monitoring and adopting an adaptive curing time adjustment method based on temperature deviation, the effect of comprehensively enhancing early hydration stability and further improving overall crack resistance is achieved.

[0066] 3. In this invention, by implementing layered controlled pouring and adopting a coordinated construction method of row-and-column uniform vibration, the ideal effect of significantly improving the overall density of concrete and reducing weak interfaces between layers is achieved.

[0067] 4. In this invention, by deploying multiple temperature measurement points at various depths and combining them with a dynamic heat preservation and adjustment strategy based on temperature gradients, a comprehensive effect of accurately controlling the internal and external temperature difference and effectively reducing thermal stress concentration is achieved. Attached Figure Description

[0068] Figure 1 This is a flowchart of the preparation method of the present invention;

[0069] Figure 2 This is a flowchart of the construction method of the present invention. Detailed Implementation

[0070] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0071] Mass concrete is widely used in construction projects, but due to its large volume and high heat of hydration, it is prone to temperature cracks and shrinkage cracks, seriously affecting the durability and safety of the structure. Currently, the industry mainly tries to alleviate the cracking problem by optimizing the mix proportion, adding admixtures, and controlling the pouring temperature, but the effect is limited. As building structures develop towards larger scale and higher strength, higher requirements are placed on the crack resistance of mass concrete.

[0072] To better understand the above technical solutions, the technical solutions of the present invention will be clearly and completely described below in conjunction with embodiments.

[0073] Example:

[0074] Reference Figure 1 This invention provides a method for preparing crack-resistant mass concrete, comprising:

[0075] Cement, fly ash, fine aggregate, coarse aggregate, water-reducing agent, and water;

[0076] The coarse aggregate is 5-25mm continuously graded crushed stone, the fine aggregate includes medium and coarse sand, and the cement includes silicate cement.

[0077] Its preparation steps include:

[0078] ZB1. Add cement, fly ash, fine aggregate and coarse aggregate to the mixing device for dry mixing;

[0079] ZB2. Add water and water-reducing agent to the dry mix and wet mix to make the concrete mixture uniform.

[0080] ZB3. Control the outlet temperature of the obtained concrete mixture within the set range and complete the preparation of crack-resistant mass concrete.

[0081] Specifically, by coordinating the composition of raw materials and the mixing process as a whole, concrete can achieve a more stable temperature development trend and structural state under large-volume conditions, thereby reducing the risk of early cracking. The combination of continuously graded coarse aggregate and medium-coarse sand and fine aggregate makes the internal skeleton structure of concrete more reasonable. The introduction of fly ash reduces the early hydration heat release level and helps to improve the uniformity of the paste structure. The combination of continuously graded crushed stone and appropriate sand ratio makes the filling between aggregates more compact, reducing the amount of paste used as a whole and the resulting shrinkage and stress concentration problems. This makes the temperature rise of concrete more gradual during the hardening process, providing a basic condition for improving the crack resistance stability of large-volume structures.

[0082] During the preparation process, dry mixing is performed first, followed by wet mixing with water and water-reducing agent. This ensures that all materials maintain a high degree of dispersion in the initial mixing stage, which helps guarantee the overall homogeneity of the mixture. The application of water-reducing agent reduces the actual water requirement while maintaining workability, making the water migration and volume change of concrete more controllable in the early hardening stage, thereby helping to suppress microcracks caused by uneven shrinkage.

[0083] After mixing, the discharge temperature of the concrete mixture is controlled to keep it within a set range. This reduces the initial temperature level from the pouring stage, which can reduce the cumulative effect of temperature peaks during subsequent hydration. This makes the temperature difference between the inside and the surface of the component more stable, which helps to reduce the problem of early thermal stress concentration. By introducing temperature control measures in the preparation stage, the concrete has a good temperature control foundation before entering the pouring and curing stages, thereby improving the crack resistance of large-volume concrete as a whole.

[0084] Reference Figure 2 This invention provides a method for constructing crack-resistant mass concrete, the method comprising the following steps:

[0085] SG1. Measure the temperature of the prepared concrete before it is poured into the formwork, and determine whether the measured value meets the set temperature range for pouring into the formwork.

[0086] SG2. Pour the concrete into the target component area in layers according to the preset layer thickness, and vibrate and compact each layer to form a stable stacking structure.

[0087] SG3. After pouring, temperature measuring points are set up at different depths of the concrete, and the temperature distribution at each depth is determined based on real-time temperature data.

[0088] SG4. Set the insulation measure adjustment amount according to the temperature distribution change, and dynamically adjust the coverage thickness or range of the insulation layer;

[0089] SG5. During the later stages of construction, the concrete should be continuously kept warm and moistened according to the temperature change pattern.

[0090] Specifically, ordinary Portland cement should be selected to fully utilize the later-stage strength of the concrete. The coarse aggregate should be continuously graded crushed stone with a particle size of 5-25mm, and the sand should be clean medium-coarse sand, with admixtures such as fly ash added, along with appropriate water-reducing agents to improve workability and lower the water-cement ratio, thereby reducing cement usage and heat of hydration. The mud content of coarse and fine aggregates should be strictly controlled; sand should not exceed 2%, and gravel should not exceed 1%. Strengthen concrete vibration to improve concrete density and tensile strength. The concrete slump should be controlled at 180±20mm to reduce autogenous shrinkage. Centralized mixing at the concrete batching plant, transportation by concrete mixer trucks, and pumping into the formwork are recommended. The slump of the foundation concrete should ideally be controlled within the range of 180±20mm. The concrete pouring speed should be controlled at 30-35 m³ / h. Concrete vibration should be performed by experienced vibrator operators. Temperature should be measured every two hours for the first three days after pouring, every four hours from days 3 to 7, and every six hours from days 7 to 14. Temperature records should be kept. If the temperature difference between the inside and outside of the concrete exceeds 25ºC, cooling measures should be taken in summer. After the concrete has initially set, the upper surface should be immediately covered with insulation materials (such as foam sponge, curing liquid, straw bags, or wet sand) and watered for curing. Excessive watering is not recommended; simply keep the concrete moist. For thick slabs, the sides should be cured using the method of retaining the formwork. In cold seasons, insulation measures should be taken by wrapping the surface with plastic film and dry straw bags. A reasonable formwork removal time should be specified to avoid a rapid temperature gradient on the concrete surface and to ensure the concrete acquires the necessary strength.

[0091] SG1 includes the following steps:

[0092] Set the temperature threshold used for determining the mold entry temperature;

[0093] Measure the real-time temperature of the concrete before it is poured into the formwork and compare it with a threshold value;

[0094] When the measured temperature deviates from the threshold range, the mold inlet temperature adjustment operation is triggered.

[0095] Among them, the temperature regulation of concrete entering the formwork includes adjusting the temperature of concrete entering the formwork by means of at least one of shading, spray cooling or reducing the transportation dwell time.

[0096] Specifically, a temperature threshold is first set for judgment. The real-time temperature of the concrete is detected before it is poured into the formwork and compared with the set range. When the temperature deviates from the range, corresponding adjustment measures will be triggered to ensure that the concrete can be poured under relatively stable initial temperature conditions.

[0097] The temperature of the concrete entering the formwork can be adjusted in a variety of ways. By using shading measures to reduce the impact of external heat radiation on the concrete, using spray cooling for short time, or optimizing the transportation and waiting process to reduce the temperature rise caused by the dwell time, the temperature can be flexibly combined according to the site conditions to quickly correct the temperature deviation and ensure that the temperature of the concrete does not deviate from the preset control range when it enters the formwork.

[0098] Through the above control measures, the concrete is kept in a relatively mild and controllable thermal state from the beginning. The temperature growth curve of the subsequent hydration heat release process will be more stable, and the development trend of the internal and surface temperature difference will be more predictable. This not only reduces the adverse effects of initial temperature fluctuations, but also lays a stable foundation for the overall temperature control management of large-volume components, thereby helping to reduce the risk of early thermal cracking and improve the consistency of construction quality.

[0099] SG2 includes the following steps:

[0100] Set the layer pouring thickness and construct the interlayer boundaries based on that thickness;

[0101] Calculate the effective pouring range of the current layer based on the layer boundary;

[0102] Vibrate the concrete within the effective range and determine whether the vibration operation needs to be repeated based on the degree of compaction.

[0103] The layer thickness of the layered pouring is 300-500mm, the pouring speed is 30-35m³ / h, the vibration adopts row and column insertion points with a spacing of 350-400mm, and the vibrator is inserted into the lower layer 45-50mm.

[0104] Specifically, by introducing a construction process that combines layered pouring with controlled vibration, the quality of structural forming during the pouring process is constrained to reduce internal defects caused by one-time pouring or uneven vibration. Before construction, the pouring structure is divided according to the set layer thickness to form clear inter-layer boundaries, so that the pouring range of each layer remains relatively independent, which is conducive to precise control of the pouring rhythm and construction quality.

[0105] During actual pouring, the effective working range of the current layer is determined based on the interlayer boundary. Only the concrete within this range is vibrated. During the vibration process, the vibration positions are arranged in a row-and-column interpolation method to make the vibration effect more uniform and avoid local over-vibration or under-vibration. By observing the compaction state of the concrete, it is determined whether additional vibration is needed to ensure that the concrete of this layer can achieve the expected compaction effect before proceeding to the next layer.

[0106] The combination of layered control and vibration method allows the concrete to form a stable and continuous internal structure during the layered accumulation and layer-by-layer compaction process. The appropriate insertion of the vibrator into the lower layer of concrete helps to bond the upper and lower layers and reduces the possibility of weak interfaces between layers. By controlling the thickness and speed of single-layer pouring, the concrete can maintain a relatively uniform state before hardening, reducing structural hazards caused by settlement differences or insufficient local compaction, thus providing favorable conditions for improving the overall crack resistance of large-volume concrete.

[0107] SG3 includes the following steps:

[0108] Set the locations of temperature measuring points at different depths;

[0109] Collect temperature data at each measuring point and calculate the temperature gradient change.

[0110] Determine whether the temperature distribution at each depth is stable based on changes in the temperature gradient.

[0111] Temperature measuring points are arranged on the concrete surface, in a shallow layer of 50–150 mm, and in a deep layer of 150–300 mm, with at least two redundant measuring points at each depth.

[0112] Specifically, by deploying temperature measuring points at different depths and continuously monitoring temperature gradients, the internal temperature changes of the structure can be understood in a more precise way. Before construction, temperature measuring points are deployed according to the location requirements at different depths, ensuring continuous monitoring of the surface, shallow layers, and deeper areas, thus forming a more comprehensive temperature observation network. Redundant measuring points are set at each depth to ensure data continuity and reliable judgment even if any sensor experiences fluctuations or malfunctions.

[0113] As the temperature develops after pouring, by synchronously collecting temperature data from each monitoring point, the temperature gradient changes between different depths can be obtained in real time. By analyzing the trends of these gradient changes, it is possible to directly determine whether the temperature field at each depth is in a stable state. When the gradient change tends to be gentle, it indicates that the internal temperature distribution is gradually becoming more balanced. If the gradient increases abnormally, it indicates that local heat accumulation or poor heat dissipation is beginning to appear.

[0114] This approach eliminates reliance on single-point data or surface temperature estimations for temperature distribution. Instead, it uses grouped data from deep distribution to assess temperature changes. By continuously observing temperature trends, it can identify potential stages where the temperature difference between the inside and outside of the structure may widen, providing more lead time for subsequent temperature control measures. It also avoids passive adjustments due to inconsistent internal and external temperature responses. With the support of multi-level temperature data, the overall temperature control process becomes more controllable and targeted, helping to improve the overall stability of large-volume concrete in its early stages.

[0115] SG4 includes the following steps:

[0116] Set the temperature deviation amount based on temperature change data;

[0117] Calculate the adjustment amount of the insulation layer based on the temperature deviation.

[0118] Adjust the coverage area or thickness of the insulation layer according to the adjustment amount.

[0119] Specifically, by analyzing the temperature change trend, the adjustment needs of the insulation measures can be further determined, so that the insulation layer can be dynamically adjusted according to the development of the on-site temperature. After obtaining continuous temperature monitoring data, by comparing the current temperature development curve with the expected control range, a value reflecting the degree of temperature deviation is given first, which is used as the basis for subsequent adjustment. This deviation can directly reflect the temperature rise or fall of the structure at different stages, thereby judging whether the current insulation state is still appropriate.

[0120] Once the deviation is determined, the required level of insulation can be calculated. Both the coverage area and the thickness can be quantified using this value. A large deviation indicates that the existing insulation conditions are insufficient, and the coverage area or insulation layer needs to be increased to mitigate the impact of the external environment on the concrete temperature. If the deviation tends to be smaller, it indicates that the temperature change is gradually stabilizing, and the insulation can transition to a more controlled approach, allowing the structure to maintain a more balanced heat dissipation process.

[0121] By employing the above methods, insulation measures are no longer fixed configurations but can be flexibly adjusted based on real-time temperature changes. As the external environment or the internal temperature of the concrete changes, the insulation intensity can be adjusted in a timely manner to stabilize the temperature field and prevent the temperature difference from widening due to excessively rapid or slow heat dissipation. This deviation-based adjustment method enhances the adaptability and continuity of the entire temperature control process, thus providing a more reliable guarantee for the early crack resistance of large-volume concrete.

[0122] SG4 also includes:

[0123] Set the maximum adjustment time for the insulation layer;

[0124] The addition or removal of insulation material is controlled according to the temperature change trend so that the adjustment of the insulation layer can be completed within a time.

[0125] The insulation measures include at least one layer of insulation with adjustable thickness or coverage area, which can be added or removed within 30–60 minutes.

[0126] Specifically, by using a time control mechanism for adjusting the insulation layer, temperature regulation becomes more flexible and meets actual construction needs. After the temperature deviation is calculated, in addition to adjusting the coverage area or thickness of the insulation layer according to the deviation, a maximum adjustment time needs to be set so that the insulation measures can be effectively implemented within a reasonable time range.

[0127] By analyzing temperature change trends, the thickness or coverage of the insulation layer can be increased or decreased as needed, ensuring that these adjustments can be completed within 30 to 60 minutes. This ensures the timeliness and continuity of temperature regulation, effectively reducing the temperature control lag problem caused by slow insulation measures, and also ensuring that excessively rapid increases or decreases in insulation measures will not have a negative impact on the hydration process of concrete.

[0128] During the implementation of thermal insulation measures, the addition or removal of the insulation layer is not only based on the judgment of the temperature deviation, but also takes into account the specific conditions of the construction site, such as changes in ambient temperature or the actual release of hydration heat inside the concrete. Through this flexible and real-time temperature control method, the management of the insulation layer becomes more intelligent and dynamic, ensuring that the temperature control at each stage meets the optimal construction requirements and effectively improving the crack resistance of large-volume concrete.

[0129] SG4 execution is based on the following triggering conditions:

[0130] When the temperature difference between any depth and the surface exceeds a set difference value, the heat preservation adjustment is triggered.

[0131] When the temperature gradient between adjacent measuring points exceeds the preset gradient value, the heat preservation adjustment is triggered.

[0132] Specifically, the system uses a dual-judgment method of temperature difference and temperature gradient to trigger and control the adjustment behavior. When the temperature difference between any internal depth and the concrete surface temperature exceeds the preset allowable range, the system determines that the current temperature distribution has deviated and immediately starts the corresponding insulation adjustment process. When the temperature change between adjacent measuring points exceeds the preset gradient limit, the system will also trigger the adjustment operation of the insulation layer to prevent the local temperature difference from amplifying rapidly.

[0133] Through the aforementioned dual-condition triggering mechanism, thermal insulation regulation no longer relies on a single temperature index, but simultaneously considers both the overall temperature difference level and the local temperature change trend. When the temperature difference between the interior and the surface gradually increases, or when the temperature change between adjacent areas is too drastic, thermal insulation regulation can be intervened in a timely manner, thereby effectively constraining the temperature development process. This avoids the waste of resources caused by premature intervention of thermal insulation measures, and also prevents the temperature control failure problem caused by delayed intervention, making the entire thermal insulation regulation process more targeted and reliable.

[0134] SG5 includes the following sub-steps:

[0135] Set the duration of moisturizing maintenance;

[0136] Determine whether additional watering is needed based on the surface moisture content;

[0137] The frequency of watering is determined by monitoring surface humidity during the maintenance period;

[0138] Among them, the maintenance time is ≥14 days.

[0139] Specifically, before starting curing, determine the required period of moisture retention to meet the minimum duration required by the project, allowing the concrete to steadily develop its performance under relatively sufficient hydration conditions. As curing progresses, observe the surface moisture to determine whether additional watering is needed. When signs of shrinkage or a decreasing humidity appear on the surface, water should be sprayed promptly to maintain a certain level of moisture and prevent early cracking caused by excessive evaporation. To maintain a more balanced humidity level, continuously monitor changes in surface humidity throughout the curing period and adjust the frequency of watering accordingly, ensuring that excessive watering does not cause surface softening, while insufficient watering does not lead to localized dryness.

[0140] The curing time is ≥14 days. In summer, the surface is covered with a layer of plastic sheeting and a layer of geotextile to slow down the heat loss of the concrete surface, gradually cool it down, give full play to the creep characteristics, and reduce temperature stress.

[0141] During winter construction, for thick, large-structure concrete with a surface coefficient M≤5, heat storage or combined heat storage methods should be used. Heat storage construction requires thermal calculations to develop an insulation plan. When the outdoor temperature is above -10℃, the concrete surface should be covered with two layers of plastic sheeting, followed by two to three layers of geotextile or cotton quilts, adjusting as needed based on temperature monitoring. The ends of components should be given special protection with thicker insulation layers. The insulation layer should be removed only after the concrete strength reaches 50% of the design strength. In the event of a sudden cold snap, it is advisable to consider backfilling and covering foundations susceptible to frost damage.

[0142] This dynamic control method based on changes in surface humidity enhances the adaptability and continuity of the wet curing process. Combined with the prescribed curing time, it allows the concrete to maintain a relatively stable hydration environment in the early stages, making the changes in humidity and volume between the surface and interior more coordinated, thereby further enhancing overall crack resistance and improving the stability of the molding quality.

[0143] SG5 also includes the following during its implementation:

[0144] The temperature deviation of the structure in the later stage is calculated based on the temperature gradient obtained in SG3;

[0145] Determine whether the insulation coverage time needs to be extended based on the deviation.

[0146] When the deviation exceeds a set threshold, a local insulation enhancement operation is triggered to bring the final temperature gradient back to a safe range.

[0147] Specifically, by combining the temperature gradient information obtained from previous monitoring, the temperature change trend of the concrete in the later stage is further evaluated to determine whether supplementary adjustments to the insulation time or insulation strength are needed. By using the gradient data obtained from the SG3 section, the temperature deviation of the current structure in subsequent development can be calculated, so that the curing measures not only depend on changes in surface humidity, but also take into account the stability of temperature distribution;

[0148] When the calculated deviation indicates that the internal temperature of the structure still exhibits an uneven trend, it can be determined whether to extend the insulation coverage time to make the cooling process more gradual and avoid excessive differences in temperature development between the surface and deeper layers. If the deviation exceeds the set allowable range, further reinforcement treatment should be applied to local areas on the basis of the original insulation to bring the temperature gradient back to a safe range. Such reinforcement measures can form an additional buffer at critical locations, making the subsequent reduction of temperature difference more stable, thereby reducing stress accumulation caused by the coupling changes in internal and external temperatures.

[0149] By incorporating temperature gradient monitoring results into the curing stage assessment system, moist curing is no longer limited to maintaining surface moisture but is instead integrated with the internal temperature balance of the structure. This not only allows for early intervention in the trend of widening temperature differences but also ensures consistency between curing measures and the overall temperature control strategy, providing more adequate protection for the safe heat dissipation and crack resistance of large-volume concrete in the later stages.

[0150] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing crack-resistant mass concrete, characterized in that, include: Cement, fly ash, fine aggregate, coarse aggregate, water-reducing agent, and water; The coarse aggregate is 5-25mm continuously graded crushed stone, the fine aggregate includes medium and coarse sand, and the cement includes silicate cement. Its preparation steps include: ZB1. The cement, fly ash, fine aggregate and coarse aggregate are added to the mixing device and dry-mixed. ZB2. Add the water and water-reducing agent to the dry mix and wet mix to make the concrete mixture uniform. ZB3. Control the outlet temperature of the obtained concrete mixture within the set range and complete the preparation of crack-resistant mass concrete.

2. A method for constructing crack-resistant mass concrete, applied to the crack-resistant mass concrete described in claim 1, characterized in that, The construction method includes the following steps: SG1. Measure the temperature of the prepared concrete before it is poured into the formwork, and determine whether the measured value meets the set temperature range for pouring into the formwork. SG2. Pour the concrete into the target component area in layers according to the preset layer thickness, and vibrate and compact each layer to form a stable stacking structure. SG3. After pouring, temperature measuring points are set up at different depths of the concrete, and the temperature distribution at each depth is determined based on real-time temperature data. SG4. Set the insulation measure adjustment amount according to the temperature distribution change, and dynamically adjust the coverage thickness or range of the insulation layer; SG5. During the later stages of construction, the concrete should be continuously kept warm and moistened according to the temperature change pattern.

3. The method for constructing crack-resistant mass concrete according to claim 2, characterized in that, The SG1 includes the following steps: Set the temperature threshold used for determining the mold entry temperature; Measure the real-time temperature of the concrete before it is poured into the formwork and compare it with the threshold value; When the measured temperature deviates from the threshold range, the mold inlet temperature adjustment operation is triggered. Among them, the temperature regulation of concrete entering the formwork includes adjusting the temperature of concrete entering the formwork by means of at least one of shading, spray cooling or reducing the transportation dwell time.

4. The method for constructing crack-resistant mass concrete according to claim 2, characterized in that, The SG2 includes the following steps: Set the layer pouring thickness and construct the interlayer boundaries based on that thickness; Calculate the effective pouring range of the current layer based on the layer boundary; Vibrate the concrete within the effective range and determine whether the vibration operation needs to be repeated based on the degree of compaction. The layer thickness of the layered pouring is 300-500mm, the pouring speed is 30-35m³ / h, and the vibration is carried out in a row-and-column pattern with a spacing of 350-400mm. The vibrator is inserted into the lower layer 45-50mm.

5. The method for constructing crack-resistant mass concrete according to claim 2, characterized in that, The SG3 includes the following steps: Set the locations of temperature measuring points at different depths; Collect temperature data at each measuring point and calculate the temperature gradient change. Determine whether the temperature distribution at each depth is stable based on changes in the temperature gradient. Temperature measuring points are arranged on the concrete surface, in a shallow layer of 50–150 mm, and in a deep layer of 150–300 mm, with at least two redundant measuring points at each depth.

6. The method for constructing crack-resistant mass concrete according to claim 2, characterized in that, The SG4 includes the following steps: Set the temperature deviation amount based on temperature change data; Calculate the adjustment amount of the insulation layer based on the temperature deviation. The coverage area or thickness of the insulation layer is adjusted according to the adjustment amount.

7. The method for constructing crack-resistant mass concrete according to claim 2, characterized in that, The SG4 also includes: Set the maximum adjustment time for the insulation layer; The addition or removal of insulation material is controlled according to the temperature change trend, so that the adjustment of the insulation layer is completed within the specified time. The insulation measures include at least one insulation layer with adjustable thickness or coverage area, which can be added or removed within 30–60 minutes.

8. The method for constructing crack-resistant mass concrete according to claim 2, characterized in that, The execution of SG4 is based on the following triggering conditions: When the temperature difference between any depth and the surface exceeds a set difference value, the heat preservation adjustment is triggered. When the temperature gradient between adjacent measuring points exceeds the preset gradient value, the heat preservation adjustment is triggered.

9. The method for constructing crack-resistant mass concrete according to claim 2, characterized in that, The SG5 includes the following sub-steps: Set the duration of moisturizing maintenance; Determine whether additional watering is needed based on the surface moisture content; The frequency of watering is determined by monitoring surface humidity during the maintenance period; The maintenance time is ≥14 days.

10. The method for constructing crack-resistant mass concrete according to claim 2, characterized in that, The SG5 process also includes: The temperature deviation of the structure in the later stage is calculated based on the temperature gradient obtained in SG3; Determine whether the insulation coverage time needs to be extended based on the deviation amount; When the deviation exceeds a set threshold, a local insulation enhancement operation is triggered to bring the final temperature gradient back to a safe range.

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