Concrete material, preparation method and open caisson blade foot large-volume pouring construction method

Abstract

The invention discloses a concrete material, a preparation method and a large-volume pouring construction method for an open caisson blade foot, and relates to the technical field of concrete materials.The concrete material is prepared from cement, fly ash, water, an additive, fine aggregate and coarse aggregate, large-volume pouring can be conducted when the concrete material is used for forming an open caisson blade foot structure, and the open caisson blade foot structure can be well formed. By changing the proportion of the materials, the requirement for large-volume concrete pouring of the open caisson blade foot can be met.

Description

Technical Field

[0001] This invention relates to the field of concrete materials technology, and in particular to a concrete material and preparation method, as well as a method for large-volume casting of caisson cutting edge. Background Technology

[0002] Concrete, as one of the most important basic materials in modern construction engineering, has undergone a development process in its pouring technology, evolving from small-scale, layered, and segmented pouring to large-volume continuous pouring. With the rapid development of infrastructure construction in my country, large-scale water conservancy projects, deep foundation pit projects, and underground space projects have placed higher demands on large-volume concrete pouring technology.

[0003] Currently, the main techniques for large-volume concrete pouring are as follows: optimizing the concrete mix proportions and adding admixtures such as retarders and water-reducing agents to slow down the hydration reaction rate and reduce the peak heat of hydration; using a layered and segmented pouring method to divide large-volume concrete into several small blocks for intermittent pouring; embedding cooling water pipes during the pouring process to remove the heat of hydration through circulating cooling water; and using low-heat cement or adding mineral admixtures such as fly ash and slag to reduce cement usage, thereby reducing the heat of hydration.

[0004] In the existing technology, the construction environment of caissons is special, with high groundwater level and limited construction space, which puts forward higher requirements for the early strength, workability and impermeability of concrete. However, the existing concrete formula is difficult to meet multiple performance requirements such as low heat of hydration, high early strength and good workability at the same time, and cannot achieve high-quality large-volume continuous casting of caissons. Summary of the Invention

[0005] The main objective of this invention is to propose a concrete material and preparation method, as well as a method for large-volume casting of caisson cutting edge. This invention aims to solve the technical problem that existing concrete formulations cannot simultaneously meet multiple performance requirements such as low heat of hydration, high early strength, and good workability, and thus cannot achieve high-quality, large-volume continuous casting of caissons, given the special construction environment of caissons, high groundwater level, and limited construction space.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a concrete material, wherein each cubic meter of the concrete material, by weight, comprises: 100 parts cement, 20 parts fly ash, 54 parts water, 2.3 parts admixture, 216 parts fine aggregate and 324 parts coarse aggregate.

[0007] In one embodiment, the cement is ordinary Portland cement.

[0008] In one embodiment, the water-cement ratio of the concrete material is A, where A ≤ 0.45.

[0009] In one embodiment, the admixture is a crack-resistant concrete waterproofing agent, which is at least one of ferric chloride, calcium chloride, silica powder, fatty acid salt, or organosilicon.

[0010] Based on the same technical concept, in a second aspect, the present invention also proposes a method for preparing the concrete material described in the first aspect, comprising the following steps: The fine aggregate, the coarse aggregate, and the water are added to a mixing device in a first preset temperature environment according to their respective weight proportions and the mixing operation is carried out to produce mixed aggregate; wherein, the ambient temperature of the first preset temperature environment is B, 20℃≤B≤25℃; The cement and fly ash are added to the mixing equipment in the corresponding weight proportions and mixed with the mixed aggregate to prepare concrete mix; The admixture is added to the concrete mix and stirred to produce the concrete material.

[0011] In one embodiment, the step of adding the fine aggregate, the coarse aggregate, and the water in corresponding weight proportions to a mixing device at a first preset temperature environment and performing a mixing operation to produce mixed aggregate includes: The fine aggregate, the coarse aggregate, and the water are added to a mixing device at a first preset temperature environment according to their corresponding weight parts and mixed for a first target time to produce a mixed aggregate; wherein, the first target time is C, and C≥30s.

[0012] In one embodiment, the step of adding the cement and the fly ash into the mixing equipment according to their corresponding weight parts and mixing them with the aggregate to prepare concrete mix includes: The cement and fly ash are added to the mixing equipment in the corresponding weight proportions and mixed with the isolated mixing equipment for a second target mixing time to produce the concrete mix; wherein, the second target mixing time is D, and D≥30s.

[0013] In one embodiment, the step of adding the admixture to the concrete mix and mixing it to produce the concrete material includes: The admixture is added to the concrete mix and stirred. The concrete material is produced after a third target time of stirring. The third target time is E, where E ≥ 60s.

[0014] Based on the same technical concept, in a third aspect, the present invention also proposes a method for large-volume casting of the cutting edge of a caisson, used for casting the concrete material prepared by the preparation method described in the second aspect; The method for large-volume casting of the caisson cutting edge includes: The concrete material is poured to the first target height within the pre-made caisson casting mold; The concrete material is vibrated and poured to form a caisson.

[0015] In one embodiment, the step of vibrating the concrete material and pouring it to form a caisson includes: The concrete material is vibrated for a preset time to form a caisson; wherein the preset time is F, 20s≤F≤30s.

[0016] The technical solution of the present invention uses concrete material made of cement, fly ash, water, admixtures, fine aggregate and coarse aggregate. When using concrete material to form the cutting edge structure of a caisson, large-volume pouring is possible. By changing the material ratio, the present invention can also meet the requirements of large-volume concrete pouring for the cutting edge of a caisson. Attached Figure Description

[0017] 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 the structures shown in these drawings without creative effort.

[0018] Figure 1 A flowchart of a method for preparing concrete materials provided by the present invention; Figure 2 This is a flowchart illustrating the large-volume casting construction method for the cutting edge of a caisson, as exemplified by the present invention.

[0019] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below 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 the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0022] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0023] In traditional caisson large-volume concrete pouring technology, excessive heat of hydration leads to uneven temperature distribution within the concrete, generating temperature stress and causing temperature cracks. Insufficient early strength development prevents the structure from meeting load-bearing requirements in a timely manner, causing interruptions in construction continuity. Poor concrete workability manifests as reduced fluidity and segregation, affecting pouring uniformity and density. Among these, temperature cracks weaken the structural integrity and impermeability, insufficient early strength prolongs the time between construction processes, and poor workability increases the difficulty of construction operations, thus systematically restricting project quality and construction efficiency.

[0024] For example, in the construction of caissons in large-scale water conservancy projects, the groundwater level is high and the working space is limited, requiring the completion of large-volume continuous pouring operations in a short period of time. Under these specific conditions, excessive heat of hydration causes the internal temperature of the concrete to rise rapidly, while the surface dissipates heat quickly, forming a temperature gradient and leading to temperature cracks. Slow early strength development necessitates an extended curing period to meet structural stability requirements, interrupting the continuity of construction. At the same time, poor workability of the concrete increases pumping resistance and causes segregation during pouring, reducing the structural density and impermeability. Specifically, this manifests as honeycomb and pitted defects on the poured surface, affecting the integrity of the caisson structure.

[0025] This invention proposes a concrete material and preparation method, as well as a method for large-volume casting of caisson cutting edge.

[0026] Please see Figures 1 to 2For ease of understanding, each cubic meter of the concrete material comprises, by weight: 100 parts cement, 20 parts fly ash, 54 parts water, 2.3 parts admixture, 216 parts fine aggregate and 324 parts coarse aggregate.

[0027] In this embodiment, the concrete mix proportion is set as follows: per cubic meter, it includes 100 parts cement, 20 parts fly ash, 54 parts water, 2.3 parts admixture, 216 parts fine aggregate, and 324 parts coarse aggregate. Fly ash refers to powdered aluminosilicate material produced by coal-fired power plants, and can be fly ash conforming to GB / T 1596 standards, such as Class F or Class C fly ash. Its main purpose is to partially replace cement to reduce the total amount of cementitious materials. Furthermore, admixtures can be water-reducing agents or retarders, such as polycarboxylate-based water-reducing agents or lignin sulfonate retarders, primarily to adjust the dispersion state and hydration reaction rate of the concrete mixture. Specifically, fine aggregate can be natural river sand or manufactured sand, and coarse aggregate can be crushed stone or pebbles, mainly to form a stable aggregate gradation structure. Therefore, this application, through precise control of the proportions of the above components, systematically coordinates the relationship between heat release of hydration, early strength development and workability, thereby effectively solving the problems of temperature cracks caused by excessive heat of hydration during the large-volume casting of caissons, insufficient early strength development affecting construction continuity, and casting difficulties caused by poor concrete workability.

[0028] This concrete material, through a scientifically designed component ratio, systematically optimizes the mix proportions, effectively reconciling the contradictions between hydration heat control, early strength development, and workability. Specifically, a combination of 100 parts cement and 20 parts fly ash is configured as the cementitious material system. Fly ash, as a mineral admixture, partially replaces cement, reducing the hydration reaction rate and peak heat release. Simultaneously, the microspheres of fly ash fill the gaps between cement particles, improving the fluidity and density of the mixture and preventing temperature cracking caused by concentrated hydration heat. The amount of water (54 parts) is precisely controlled, matching the total cementitious material of 120 parts, ensuring sufficient fluidity for large-volume pouring to maintain construction continuity, while avoiding strength degradation and shrinkage cracking risks caused by excessive water. 2.3 parts of admixture are introduced to participate in the hydration process, enhancing the concrete's crack resistance and impermeability by adjusting the dispersion state of cement particles and slowing down the hydration reaction rate, effectively inhibiting the formation of early plastic shrinkage cracks. The gradation ratio of 216 parts fine aggregate to 324 parts coarse aggregate was optimized to form a stable skeleton structure. The fine aggregate filled the gaps between the coarse aggregate, improving the density, while the coarse aggregate provided volume stability. The synergistic effect of the two reduced the overall shrinkage deformation of the concrete, while optimizing the uniformity and workability of the mixture, ensuring the continuous operation requirements of large-volume pouring.

[0029] Specifically, in one embodiment, 100 kg of cement, 20 kg of fly ash, 54 kg of water, 2.3 kg of admixture, 216 kg of fine aggregate, and 324 kg of coarse aggregate are weighed per cubic meter of concrete material, and then added to a mixing device and mixed evenly. This mix design exhibits low heat of hydration during large-volume caisson casting, effectively suppressing the formation of temperature cracks. Simultaneously, its good workability ensures the continuity and quality of casting, avoiding construction interruptions or quality problems due to insufficient material properties, thus providing a reliable basic material guarantee for high-quality, large-volume continuous casting of caisson structures.

[0030] In this embodiment, by using concrete material made of cement, fly ash, water, admixtures, fine aggregate and coarse aggregate, large-volume pouring can be carried out when using concrete material to form the caisson cutting edge structure. By changing the material ratio, the present invention can also meet the requirements of large-volume concrete pouring for the caisson cutting edge.

[0031] In one embodiment, the cement is ordinary Portland cement.

[0032] Specifically, ordinary silicate cement refers to silicate cement that conforms to the national standard GB 175. It can be achieved using cement of grade P·O 42.5 or P·O 52.5. The purpose is to regulate the heat of hydration release rate and ensure early strength development by using an appropriate tricalcium silicate content.

[0033] Specifically, the solution proposed in this application achieves a balance between the release of hydration heat and strength development in the concrete material during the large-volume casting of the caisson by limiting the cement type to ordinary Portland cement. The mineral composition characteristics of ordinary Portland cement determine its moderate hydration reaction rate, which can provide sufficient early strength to support the caisson structure in the initial stage of casting, while avoiding a sudden temperature rise caused by concentrated release of hydration heat. This material selection results in a more uniform temperature distribution inside the concrete, reducing temperature stress caused by temperature differences between the inside and outside, thereby effectively inhibiting the formation of cracks. Under the special working conditions of continuous casting at the caisson cutting edge, this cement type also ensures the stability of the concrete's workability, maintaining the material's impermeability and structural continuity in the groundwater environment.

[0034] In some preferred embodiments, the ordinary Portland cement used in the concrete material of this application can be P·O 42.5 grade cement conforming to national standards. After being mixed with fly ash, water and other components, this cement exhibits a moderate hydration rate during the casting process of the caisson cutting edge, enabling the concrete to form supporting strength in a short time after casting. At the same time, the heat release process of hydration is more gradual, avoiding temperature stress concentration.

[0035] Through the above technical solutions, the concrete material achieves a coordinated balance between the release of hydration heat and early strength development during the large-volume casting of caissons, effectively suppressing the generation of temperature cracks and ensuring the integrity and impermeability of the caisson structure.

[0036] In one embodiment, the water-cement ratio of the concrete material is A, where A ≤ 0.45.

[0037] In practical applications, the water-cement ratio refers to the weight ratio of water to cementitious materials (including cement and fly ash) in concrete. It can be achieved by accurately measuring the weight of water and cementitious materials during the preparation process. The purpose is to ensure that the water ratio in the cementitious material system is within the optimal range, avoid the dilution effect caused by excessive water, thereby maintaining a high early strength development rate and inhibiting the excessive concentrated release of hydration heat.

[0038] Specifically, the solution proposed in this application strictly controls the water-cement ratio to 0.45 or below, ensuring that the water content in the cementitious material system composed of cement and fly ash is limited to a threshold range that avoids dilution effects. This not only guarantees the full hydration reaction of the cementitious material to maintain the early strength development rate, but also effectively inhibits the concentrated release of heat from the hydration reaction, reducing the risk of internal temperature gradient formation during large-volume casting. This limitation, in synergy with the incorporation characteristics of fly ash, strengthens the densification process of the cementitious material, improves the crack resistance and structural stability of the concrete, and at the same time takes into account the workability requirements, enabling the material to adapt to the harsh conditions of continuous casting at the caisson cutting edge, reducing deep cracks caused by uncontrolled heat of hydration.

[0039] As a specific implementation method, the concrete material of this application is prepared with a water-cement ratio controlled at 0.42, which is achieved by adjusting the ratio of water and cementitious materials, for example, by reducing the amount of water or increasing the weight of cementitious materials per cubic meter of concrete, to ensure that the water-cement ratio is within the optimized range.

[0040] The above solutions effectively improved the early strength of concrete, controlled the peak heat of hydration, reduced the superposition effect of temperature stress and shrinkage stress during the large-volume casting of caissons, significantly reduced the risk of cracking, ensured the integrity and durability of the structure, and met the comprehensive requirements of high strength and impermeability of the caisson cutting edge under high groundwater levels and restricted construction environments.

[0041] In one embodiment, the admixture is a crack-resistant concrete waterproofing agent, which is at least one of silica powder, fatty acid salt, or organosilicon.

[0042] Specifically, crack-resistant concrete waterproofing agent refers to an additive that can simultaneously inhibit concrete cracking and enhance waterproofing performance. It can be achieved by using one or more combinations of ferric chloride, calcium chloride, silica powder, fatty acid salts, or organosilicon. Its purpose is to solve the problems of increased brittleness and water seepage in concrete under low water-cement ratio conditions through multiple mechanisms in a synergistic manner. Silica powder can play a micro-filling effect to optimize the internal pore structure of concrete, with the aim of enhancing the density of the matrix to resist external stress. Fatty acid salts or organosilicon can utilize their hydrophobic properties to form a continuous waterproof membrane at the aggregate interface, with the aim of effectively blocking the migration path of moisture.

[0043] Specifically, the solution of this application limits the admixture to a crack-resistant concrete waterproofing agent and specifies that its components are at least one of ferric chloride, calcium chloride, silica powder, fatty acid salt, or organosilicon, so that these components form an organic whole in the concrete: ferric chloride and calcium chloride accelerate the hydration reaction and generate precipitates that preferentially seal early micro-cracks, while silica powder fills the matrix pores and improves density, and the waterproof membrane built by fatty acid salt or organosilicon at the aggregate interface blocks the water penetration channel. The synergistic effect of the three ensures that the concrete achieves crack resistance and waterproofing functions simultaneously under low water-cement ratio conditions, avoiding the structural durability defects caused by traditional admixtures that only focus on a single performance.

[0044] When preparing concrete, a mixture of ferric chloride and organosilicon is used as an admixture. Ferric chloride provides rapid reaction capability to accelerate cement hydration and generate ferric hydroxide precipitate to seal pores, while organosilicon forms a hydrophobic layer on the surface of aggregates to prevent moisture migration. This combination can be evenly dispersed in the concrete mix during the mixing process, effectively improving the overall crack resistance and waterproof performance of the material.

[0045] Through the above-mentioned solution, this application effectively alleviates the tendency of early cracking of concrete caused by low water-cement ratio, significantly enhances impermeability, ensures the structural integrity and waterproof reliability during the large-volume casting construction of the caisson cutting edge, and reduces the risk of groundwater leakage.

[0046] Based on the same technical concept, in a second aspect, the present invention also proposes a method for preparing the concrete material described in the first aspect, comprising the following steps: S100. The fine aggregate, the coarse aggregate, and the water are added to a mixing device in a first preset temperature environment according to their respective weight proportions and the mixing operation is carried out to produce mixed aggregate; wherein, the ambient temperature of the first preset temperature environment is B, 20℃≤B≤25℃. S200. The cement and fly ash are added to the mixing equipment according to the corresponding weight parts and mixed with the mixed aggregate to prepare concrete mix; S300. Add the admixture to the concrete mix and stir to produce the concrete material.

[0047] By combining a phased mixing process with a first preset temperature environment control, specifically preparing mixed aggregates within a temperature range of 20℃ to 25℃ to suppress early hydration reactions when aggregates come into contact with water, then introducing cement and fly ash to optimize particle size distribution and reduce the total amount of cementitious materials, and finally adding admixtures in the concrete mixing stage to ensure uniform dispersion, the contradiction between hydration heat release, early strength development, and workability is effectively coordinated. This solves the problem that concrete materials in large-volume caisson casting cannot simultaneously meet the requirements of low hydration heat, high early strength, and good workability, thus achieving the goal of high-quality continuous casting.

[0048] Specifically, the initial preset temperature environment avoids the impact of ambient temperature fluctuations on the initial mixture, reduces heat accumulation, and alleviates the temperature stress problem of large-volume concrete. The mixing of cement and fly ash not only reduces the peak heat of hydration but also enhances the fluidity and density of the mixture by filling the gaps between cement particles with microspheres. The timing of the addition of admixtures in the concrete mixing stage ensures their functionality, strengthens crack resistance and impermeability, and meets the comprehensive requirements of early strength and durability for caisson construction. In practical applications, this method systematically optimizes the concrete preparation process by precisely controlling the process parameters at each stage, effectively suppressing the generation of temperature cracks, ensuring the continuity of pouring and structural quality, and providing reliable technical support for the continuous pouring of large-volume caissons.

[0049] In one embodiment, step S100 includes: The fine aggregate, the coarse aggregate, and the water are added to a mixing device at a first preset temperature environment according to their corresponding weight parts and mixed for a first target time to produce a mixed aggregate; wherein, the first target time is C, and C≥30s.

[0050] The first preset temperature environment refers to the ambient temperature range of the mixing equipment, which can be set to a constant temperature condition of 20℃ to 25℃. This can be achieved by using a constant temperature mixing station or a temperature control system. Its purpose is to maintain the temperature stability during the mixing process of aggregate and water, thereby optimizing the mixing efficiency. The first target mixing time C refers to the minimum duration threshold of the mixing operation during the preparation of mixed aggregates. It can be 30 seconds or longer, specifically 35 seconds or 40 seconds, etc. Its purpose is to ensure that the aggregate particles and water molecules have enough time to complete the uniform dispersion and avoid local uneven drying and wetting.

[0051] Specifically, the solution of this application limits the first target mixing time C to no less than 30 seconds under the first preset temperature environment, so that fine aggregate, coarse aggregate and water can form sufficient contact and dynamic equilibrium during the mixing process. The setting of this time threshold is based on the influence of temperature environment on aggregate particle size distribution and water molecule penetration, ensuring that the mixed aggregate reaches a structurally stable state in the shortest time, effectively avoiding mixing defects caused by short-time mixing, thus laying a uniform foundation for the subsequent addition of cement and fly ash, and ensuring the continuity and crack resistance of concrete materials in large-volume pouring.

[0052] Through the above-mentioned solution, this application effectively improves the uniformity of aggregate and water mixing, ensures precise control of water-cement ratio and workability stability, reduces the risk of cracking in the large-volume caisson casting construction, and guarantees construction quality.

[0053] In one embodiment, step S200 includes: The cement and fly ash are added to the mixing equipment in the corresponding weight proportions and mixed with the isolated mixing equipment for a second target mixing time to produce the concrete mix; wherein, the second target mixing time is D, and D≥30s.

[0054] The input of cement and fly ash according to their corresponding weight proportions refers to the precise measurement of powder components according to a preset ratio. This can be achieved using an electronic weighing system or an automated batching device. The purpose is to ensure the accuracy of the material ratio and lay the foundation for subsequent uniform mixing. Mixing with aggregates refers to the mechanical mixing of powder and aggregates. This can be achieved using a forced mixer or a gravity mixer. The purpose is to promote the initial bonding between materials. The second target mixing time D refers to setting a minimum mixing time threshold. This can be achieved using a timer controller or a programmable logic unit. The purpose is to provide sufficient mixing time so that cement particles and fly ash are fully dispersed and uniformly adhered to the aggregate surface.

[0055] Specifically, the solution in this application ensures thorough mixing of cement, fly ash, and aggregates within a reasonable timeframe by precisely controlling the mixing time. Adding cement and fly ash according to their weight proportions guarantees accurate material ratios. Subsequently, mixing with the aggregates and maintaining a mixing time of at least 30 seconds provides necessary dispersion time for cement particles and fly ash, allowing them to adhere evenly to the aggregate surface and preventing localized enrichment or separation caused by short-duration mixing. Ultimately, the resulting concrete mix exhibits high homogeneity, providing a reliable guarantee for the subsequent addition of admixtures and the performance stability of concrete materials.

[0056] In the mixing equipment, cement and fly ash are precisely added according to their weight proportions and mixed together with the aggregate. The mixing time is set to 35 seconds to produce a uniform concrete mix.

[0057] Through the above solution, this application effectively solves the problem of insufficient mixing of cement and fly ash with aggregates, improves the uniformity and structural strength of concrete mix, and prevents the risk of strength weaknesses or cracks caused by insufficient mixing.

[0058] In one embodiment, step S300 includes: The admixture is added to the concrete mix and stirred. The concrete material is produced after a third target time of stirring. The third target time is E, where E ≥ 60s.

[0059] The third target duration refers to a specific time parameter for mixing admixtures, which can be achieved using 60 seconds or longer. Specifically, the mixing process can be controlled by an automatic timing system or manual timing. The purpose is to provide a sufficient time window for the admixture components to fully dissolve and penetrate into all parts of the concrete mix, thereby avoiding mixing defects caused by excessively high or low admixture concentrations in local areas.

[0060] Specifically, the solution of this application achieves a dynamic mixing system by precisely controlling the mixing time after the admixture is added to the concrete mix. The setting of a mixing time E≥60s ensures that the admixture components, such as ferric chloride or organosilicon, are evenly dispersed, while preventing uneven dispersion caused by too short a mixing time or air mixing introduced by too long a mixing time. This optimizes the interaction mechanism between the admixture and the concrete mix as a whole.

[0061] In the mixing equipment, after the admixture is added to the concrete mix, the mixer is started and run continuously for 60 seconds. During the operation, the uniformity of the concrete material is observed to confirm that the admixture has been fully mixed, thereby producing concrete material that meets the performance requirements.

[0062] Through the above technical solution, this application effectively prevents the risk of uneven internal stress and cracks in concrete materials caused by uneven distribution of admixtures, ensures the uniformity and structural integrity of concrete, and provides a stable and reliable material foundation for the large-volume casting of caisson cutting edge.

[0063] Based on the same technical concept, in a third aspect, the present invention also proposes a method for large-volume casting of the cutting edge of a caisson, used for casting the concrete material prepared by the preparation method described in the second aspect; The method for large-volume casting of the caisson cutting edge includes: A100. The concrete material is poured to the first target height in the pre-made caisson casting mold; A200, Vibrate the concrete material and pour it to form a caisson.

[0064] By systematically combining the low heat of hydration, high early strength, and good workability of the concrete material prepared by the aforementioned method with a refined casting process, the accumulation of temperature stress is effectively suppressed during the large-volume casting of the caisson's cutting edge. This reduces the risk of internal cracks caused by excessively high peak heat of hydration, while ensuring construction continuity and structural integrity. Specifically, the concrete material prepared by the aforementioned method reduces the heat of hydration release rate through optimized component ratios, avoiding crack propagation caused by temperature gradients; process control at the first target height ensures uniform concrete distribution and continuous operation, preventing segregation or cold joint formation; and precise vibration operation eliminates air bubbles within the material, enhancing density and impermeability. Through these technical solutions, quality defects in the caisson structure are effectively controlled, significantly improving the construction efficiency and structural reliability of large-volume continuous casting. Specifically, in the large-volume pouring construction of the caisson cutting edge, the duration of vibration operation is not limited, which can easily lead to insufficient or excessive vibration, resulting in air bubbles or aggregate segregation inside the concrete, which in turn causes cracks and insufficient strength, affecting the overall quality and construction efficiency of the caisson.

[0065] In one embodiment, step A200 includes: The concrete material is vibrated for a preset time to form a caisson; wherein the preset time is F, 20s≤F≤30s.

[0066] The preset duration F refers to the duration of the vibration operation, which can be set to specific values ​​such as 20 seconds, 25 seconds or 30 seconds. Its purpose is to ensure that the concrete fully removes internal air bubbles during the vibration process to achieve the required density, while avoiding the separation of aggregate and paste due to excessive time, thereby maintaining the uniformity of materials and structural stability.

[0067] Specifically, the solution in this application controls the vibration time within a specific range of 20 to 30 seconds, effectively matching the vibration process with the characteristics of the concrete material and the preparation process. Since parameters such as the water-cement ratio, admixture type, and mixing temperature of the concrete material have been optimized, its workability and setting characteristics are at an appropriate level. Within this range, the vibration time ensures sufficient energy transfer to remove air bubbles while preventing aggregate settlement caused by excessive vibration, thereby ensuring the continuity and overall quality of the large-volume casting of the caisson's cutting edge.

[0068] Through the above solution, this application effectively solves the problem of internal defects in concrete caused by improper vibration time, and significantly improves the overall strength and construction efficiency of the caisson structure.

[0069] The above description is merely an exemplary embodiment of the present invention and does not limit the scope of the present invention. Any equivalent structural transformations made based on the technical concept of the present invention and the contents of the specification and drawings of the present invention, or direct / indirect applications in other related technical fields, are included within the protection scope of the present invention.

Claims

1. A concrete material, characterized in that, The concrete material includes, by weight per cubic meter: 100 parts of cement, 20 parts of fly ash, 54 parts of water, 2.3 parts of an additive, 216 parts of fine aggregate, and 324 parts of coarse aggregate.

2. The concrete material of claim 1, wherein, The cement is ordinary Portland cement.

3. The concrete material of claim 2, wherein, The water-binder ratio of the concrete material is A, and A≤0.

45.

4. The method for preparing concrete material as described in claim 3, characterized in that, The additive is a crack-resistant concrete waterproofing agent, and the crack-resistant concrete waterproofing agent is at least one of iron chloride, calcium chloride, siliceous powder, a fatty acid salt, or organosilicon.

5. A method for producing a concrete material as claimed in any one of claims 1 to 4, characterized in that, The method includes the following steps: The fine aggregate, the coarse aggregate, and the water are put into a mixing device in a first preset temperature environment according to the corresponding weight parts and are stirred to produce a mixed aggregate; the first preset temperature environment has an ambient temperature of B, and 20℃≤B≤25℃. The cement and the fly ash are put into the mixing device according to the corresponding weight parts and are stirred with the mixed aggregate to produce a concrete mixture. The additive is put into the concrete mixture and is stirred to produce the concrete material.

6. The method for preparing concrete material as described in claim 5, characterized in that, The step of putting the fine aggregate, the coarse aggregate, and the water into the mixing device in the first preset temperature environment according to the corresponding weight parts and stirring to produce the mixed aggregate includes: The fine aggregate, the coarse aggregate, and the water are put into the mixing device in the first preset temperature environment according to the corresponding weight parts and are stirred for a first target time to produce the mixed aggregate; the first target time is C, and C≥30s.

7. The method for preparing concrete material as described in claim 5, characterized in that, The step of putting the cement and the fly ash into the mixing device according to the corresponding weight parts and stirring with the mixed aggregate to produce the concrete mixture includes: The cement and the fly ash are put into the mixing device according to the corresponding weight parts and are stirred with the mixed aggregate for a second target time to produce the concrete mixture; the second target time is D, and D≥30s.

8. The method for preparing concrete material as described in claim 5, characterized in that, The step of putting the additive into the concrete mixture and stirring to produce the concrete material includes: The additive is put into the concrete mixture and is stirred for a third target time to produce the concrete material; the third target time is E, and E≥60s.

9. A method for constructing a large volume of a caisson blade foot, characterized by, The concrete material produced by the preparation method of any one of claims 5 to 8 is used for pouring. The method includes the following steps: The concrete material is poured to a first target height in a prepared caisson pouring mold; The concrete material is vibrated and poured.

10. The method of claim 9, wherein the method further comprises the step of: The step of vibrating and pouring the concrete material includes: The concrete material is vibrated for a preset time to complete pouring; the preset time is F, and 20s≤F≤30s.

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