Construction methods for large-volume concrete structures

Abstract

The present invention provides a method for constructing a large-volume concrete structure, which relates to the technical field of concrete structure construction. The method for constructing a large-volume concrete structure comprises: dividing the large-volume concrete structure into multiple layers from bottom to top, and dividing each layer of concrete structure into a bottom structure, a middle structure, and a surface structure from bottom to top; casting multiple layers of concrete structures from bottom to top, and when casting any layer of concrete structure, casting the bottom structure concrete, the middle structure concrete, and the surface structure concrete from bottom to top, and adding a hydration heat inhibitor to at least the concrete of the bottom structure and the middle structure, so that the temperature peak time of the concrete of the bottom structure, the middle structure, and the surface structure is the same. The construction method can reduce the internal and external temperature difference of the large-volume concrete structure by adding a hydration heat inhibitor to the concrete, effectively reduce temperature cracks, and does not require the laying of cooling water pipes, which can save manpower and steel costs, simplify construction steps, and improve construction efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete structure construction, in particular to a large-volume concrete structure construction method. Background Art

[0002] The cement in concrete generates heat during the hydration process. During the construction phase, large-volume concrete structures such as anchors (huge components used to fix the ends of main cables to prevent them from moving) have a large volume of concrete to be poured at one time and their own geometric dimensions are not small. Therefore, the heat released by the cement hydration reaction is difficult to transfer to the surface under natural conditions. This causes the internal temperature of the concrete structure to rise sharply, while the external temperature is relatively low, resulting in a large temperature difference between the inside and outside of the concrete structure, causing temperature stress that causes the surface to be tensile, and ultimately causes cracks in the concrete, which has low tensile strength, to destroy its integrity, change the stress on the structure, weaken the function of the concrete structure, and threaten the safety of the entire project.

[0003] In order to solve the cracking problem of large-volume concrete structures, one existing measure is to pre-embed a large number of steel cooling water pipes in the large-volume concrete structure, and use the cooling water in the cooling water pipes to cool the interior of the large-volume concrete structure, thereby reducing the temperature difference between the inside and outside of the large-volume concrete structure, reducing temperature stress, and improving the concrete's crack resistance.

[0004] However, the construction steps of arranging cooling water pipes, circulating cooling water, and subsequently grouting the cooling water pipes not only consume a large amount of manpower and steel, but also increase construction time and reduce construction efficiency. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for constructing large-volume concrete structures to alleviate the technical problem in the prior art of using cooling water in pre-buried cooling water pipes to cool the interior of large-volume concrete structures to reduce the temperature difference between the inside and outside of the concrete structures, which not only consumes a large amount of manpower and steel, but also increases construction time and reduces construction efficiency.

[0006] In a first aspect, the present invention provides a method for constructing a large-volume concrete structure, comprising:

[0007] The large-volume concrete structure is divided into multiple layers from bottom to top, and each layer of concrete structure is divided into a bottom structure, a middle structure and a surface structure from bottom to top;

[0008] A multi-layer concrete structure is cast successively from bottom to top, and when casting any layer of concrete structure, the concrete of the bottom structure, the concrete of the middle structure and the concrete of the surface structure in the layer of concrete structure are cast successively from bottom to top, and a hydration heat inhibitor is added to at least the concrete of the bottom structure and the concrete of the middle structure; the hydration heat inhibitor is used to delay the temperature peak time during the concrete temperature change process, so that the temperature peak time of the bottom structure concrete, the temperature peak time of the middle structure concrete and the temperature peak time of the surface structure concrete are the same.

[0009] In an optional embodiment, a hydration heat inhibitor is added to the concrete of the surface structure, and the amount of the hydration heat inhibitor in the bottom structure concrete and the amount of the hydration heat inhibitor in the middle structure concrete are both greater than the amount of the hydration heat inhibitor in the surface structure concrete.

[0010] In an optional embodiment, the dosage of the hydration heat inhibitor in the bottom structure concrete and the dosage of the hydration heat inhibitor in the middle structure concrete are both 4.5-4.7‰, and the dosage of the hydration heat inhibitor in the surface structure concrete is 0-3.0‰.

[0011] In an optional embodiment, the hydration heat inhibitor is an organic polyphosphonic acid.

[0012] In an optional embodiment, in the concrete of the bottom structure, the concrete of the middle structure and the concrete of the surface structure, fly ash is added to the cementitious material of the concrete mixed with the hydration heat inhibitor, and the proportion of the fly ash in the cementitious material is not less than 40%.

[0013] In an optional embodiment, in the concrete of the bottom structure, the concrete of the middle structure and the concrete of the surface structure, the cementitious material of the concrete mixed with the hydration heat inhibitor is mixed with slag powder, and the proportion of the slag powder in the cementitious material is no more than 40%.

[0014] In an optional embodiment, when pouring any layer of concrete structure, the start time of pouring the concrete of the middle structure does not exceed the initial setting time of the concrete of the bottom structure; and the start time of pouring the concrete of the surface structure does not exceed the initial setting time of the concrete of the middle structure.

[0015] In an optional embodiment, the thickness of each layer of the concrete structure is 30-50 cm.

[0016] In an optional embodiment, the concrete of the bottom structure, the concrete of the middle structure, and the concrete of the surface structure are all mixed with a polycarboxylic acid water reducer.

[0017] In an optional embodiment, when pouring any layer of concrete structure, after pouring the concrete of the surface structure, a thermal insulation layer is covered on the surface of the surface structure.

[0018] The method for constructing a large-volume concrete structure provided by the present invention comprises: dividing the large-volume concrete structure into multiple layers from bottom to top, and dividing each layer of concrete structure into a bottom structure, a middle structure and a surface structure from bottom to top; casting the multiple layers of concrete structure from bottom to top, and when casting any layer of concrete structure, casting the concrete of the bottom structure, the concrete of the middle structure and the concrete of the surface structure of the layer from bottom to top, and adding a hydration heat inhibitor to at least the concrete of the bottom structure and the concrete of the middle structure; the hydration heat inhibitor is used to delay the temperature peak time during the temperature change of the concrete, so that the temperature peak time of the bottom structure concrete, the temperature peak time of the middle structure concrete and the temperature peak time of the surface structure concrete are the same. The large-volume concrete structure constructed using this large-volume concrete structure construction method has concrete in the bottom structure and the middle structure of any layer of concrete structure mixed with hydration heat inhibitors, and the hydration heat inhibitors can delay the temperature peak time during the temperature change of concrete, so that the hydration heat temperature peaks of the concrete of the bottom structure and the concrete of the middle structure are delayed, so that the temperature peak time of the bottom structure concrete, the temperature peak time of the middle structure concrete and the temperature peak time of the surface structure concrete are the same. At this time, the hydration rates of the concrete of the bottom structure, the concrete of the middle structure and the concrete of the surface structure are relatively uniform, thereby making the temperature rise of each layer of concrete structure more uniform. When the overall large-volume concrete structure is constructed according to the above steps, the temperature difference between the inside and outside of the large-volume concrete structure can be effectively reduced, thereby reducing the temperature cracks generated inside the large-volume concrete structure. The large-volume concrete structure construction method provided by the present invention can reduce the internal and external temperature difference of each layer of concrete structure by adding a hydration heat inhibitor to at least the bottom concrete structure and the middle concrete structure of the corresponding layer of concrete structure when constructing each layer of concrete structure, thereby reducing the internal and external temperature difference of the entire large-volume concrete structure. Therefore, there is no need to pre-embed a large number of cooling water pipes inside the large-volume concrete structure, nor is there any need to pass water and grouting into the cooling water pipes. This can effectively reduce the use of manpower and steel, reduce manpower and steel costs, and at the same time simplify construction steps and improve construction efficiency.

[0019] Compared with the existing technology, the large-volume concrete structure construction method provided by the present invention not only delays the temperature peak time of the bottom structure concrete and the middle structure concrete by adding a hydration heat inhibitor into the concrete, thereby reducing the temperature difference between the inside and outside of the large-volume concrete structure and effectively reducing temperature cracks, but also does not require the laying of cooling water pipes, which can save manpower and steel costs, and can simplify construction steps and improve construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 A schematic structural diagram of a large-volume concrete structure provided by an embodiment of the present invention;

[0022] Figure 2 A flowchart of a method for constructing a large-volume concrete structure according to an embodiment of the present invention;

[0023] Figure 3 A line graph showing the compressive strength of concrete samples containing different amounts of hydration heat inhibitors according to an embodiment of the present invention;

[0024] Figure 4 This is a line graph showing the flexural strength of concrete samples containing different amounts of hydration heat inhibitors provided by an embodiment of the present invention.

[0025] Icon: 1- bottom structure; 2- middle structure; 3- surface structure. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0028] The following embodiments of the present invention are described in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0029] Example:

[0030] like Figure 1 and Figure 2As shown, the mass concrete structure construction method provided in this embodiment includes:

[0031] Step S1: Divide the large-volume concrete structure into multiple layers from bottom to top, and divide each layer of the concrete structure into a bottom structure 1, a middle structure 2, and a surface structure 3 from bottom to top;

[0032] Step S2: Casting a multi-layer concrete structure from bottom to top, and when casting any layer of concrete structure, cast the concrete of the bottom structure 1, the concrete of the middle structure 2 and the concrete of the surface structure 3 in the layer of concrete structure from bottom to top, and add a hydration heat inhibitor to at least the concrete of the bottom structure 1 and the concrete of the middle structure 2; the hydration heat inhibitor is used to delay the temperature peak time during the temperature change of the concrete, so that the temperature peak time of the concrete of the bottom structure 1, the temperature peak time of the concrete of the middle structure 2 and the temperature peak time of the concrete of the surface structure 3 are the same.

[0033] The large-volume concrete structure constructed using this large-volume concrete structure construction method has concrete in the bottom structure 1 and the middle structure 2 in any layer of the concrete structure mixed with hydration heat inhibitors, and the hydration heat inhibitors can delay the temperature peak time during the concrete temperature change process, so that the hydration heat temperature peaks of the concrete of the bottom structure 1 and the concrete of the middle structure 2 are delayed, so that the temperature peak time of the concrete of the bottom structure 1, the temperature peak time of the concrete of the middle structure 2 and the temperature peak time of the concrete of the surface structure 3 are the same. At this time, the hydration rates of the concrete of the bottom structure 1, the concrete of the middle structure 2 and the concrete of the surface structure 3 are relatively uniform, thereby making the temperature rise of each layer of the overall concrete structure more uniform. When the overall large-volume concrete structure is constructed according to step S2, the temperature difference between the inside and outside of the large-volume concrete structure can be reduced, thereby reducing the temperature cracks generated inside the large-volume concrete structure.

[0034] It can be seen that the large-volume concrete structure construction method provided in this embodiment can reduce the internal and external temperature difference of each layer of concrete structure by adding a hydration heat inhibitor to at least the bottom concrete structure and the middle concrete structure of the corresponding layer of concrete structure when constructing each layer of concrete structure, thereby reducing the internal and external temperature difference of the entire large-volume concrete structure. Therefore, there is no need to pre-embed a large number of cooling water pipes inside the large-volume concrete structure, nor is there any need to pass water and grouting into the cooling water pipes. Therefore, the large-volume concrete structure construction method provided in this embodiment can effectively reduce the use of manpower and steel, reduce manpower and steel costs, and at the same time simplify construction steps and improve construction efficiency.

[0035] Compared with the existing technology, the large-volume concrete structure construction method provided in this embodiment not only delays the temperature peak time of the bottom structure 1 concrete and the middle structure 2 concrete by adding a hydration heat inhibitor into the concrete, thereby reducing the internal and external temperature difference of the large-volume concrete structure and effectively reducing temperature cracks, but also does not require the laying of cooling water pipes, which can save manpower and steel costs, and can simplify construction steps and improve construction efficiency.

[0036] It should be noted that even though the present embodiment uses a hydration heat inhibitor, the overall construction cost is still reduced compared to the overall construction cost of laying cooling water pipes.

[0037] Table 1 shows the mix ratio of mass concrete when water cooling is used and the mix ratio of mass concrete when the hydration heat inhibitor in this scheme is used:

[0038] Table 1

[0039]

[0040]

[0041] Table 2 is the price data of each component material in concrete:

[0042] Table 2

[0043]

[0044] The data in Table 3 can be calculated from the above two tables. Table 3 is an analysis table of the comprehensive cost of large-volume concrete structures when water cooling is used and the comprehensive cost of large-volume concrete when the hydration heat inhibitor in this scheme is used:

[0045]

[0046] According to Table 3, it can be seen that the comprehensive construction cost can be reduced by replacing the pre-buried cooling water pipe temperature control technology solution with the addition of hydration heat inhibitor.

[0047] In this embodiment, a hydration heat inhibitor is added to the concrete of the surface structure 3, and the amount of the hydration heat inhibitor in the concrete of the bottom structure 1 and the amount of the hydration heat inhibitor in the concrete of the middle structure 2 are both greater than the amount of the hydration heat inhibitor in the concrete of the surface structure 3.

[0048] When a hydration heat inhibitor is also added to the concrete of the surface structure 3, in order to ensure that the temperature difference between the inside and the surface of each layer of concrete structure can still be reduced, the amount of hydration heat inhibitor added to the concrete of the surface structure 3 needs to be smaller than the amount of hydration heat inhibitor added to the concrete of the bottom structure 1, and smaller than the amount of hydration heat inhibitor added to the concrete of the middle structure 2. At this time, the amount of hydration heat inhibitor added to the concrete of each layer of concrete structure is distributed in a gradient, so that the hydration rate of different concrete layers can be gradiently controlled, achieving the purpose of homogenizing the concrete hydration rate and homogenizing the temperature of each layer of concrete structure, thereby reducing the temperature stress caused by the internal and external temperature difference of large-volume concrete structures.

[0049] It can be seen that compared with the dosage of hydration heat inhibitor in the concrete of the surface structure 3, the dosage of hydration heat inhibitor in the concrete of the bottom structure 1 and the dosage of hydration heat inhibitor in the concrete of the middle structure 2 are both large. The large dosage of hydration heat inhibitor can delay the hydration heat release time of the concrete poured first, and the small dosage of hydration heat inhibitor in the concrete of the surface structure 3 can make the concrete of the surface structure 3 release heat at the same time as the middle and bottom concrete structures below it, thereby shortening the temperature difference between the inside and outside of the overall concrete structure.

[0050] It should also be noted that even if a hydration heat inhibitor is added to the concrete of the surface structure 3, the amount of hydration heat inhibitor added can ensure that the concrete of the surface structure 3 will produce a hydration reaction in about 24 hours, thereby preventing the concrete of the surface structure 3 from releasing heat too late and affecting the strength of the concrete of the surface structure 3 after solidification.

[0051] Furthermore, the dosage of the hydration heat inhibitor in the concrete of the bottom structure 1 and the dosage of the hydration heat inhibitor in the concrete of the middle structure 2 are both 4.5-4.7‰, and the dosage of the hydration heat inhibitor in the concrete of the surface structure 3 is 0-3.0‰.

[0052] The above-mentioned hydration heat inhibitor with a dosage of 4.5-4.7‰ and 0-3.0‰ can not only delay the temperature peak time of concrete at the bottom and middle parts of each layer of concrete structure, but also reduce the temperature peak by 20%-30%, so that the temperature difference between the inside and outside of each layer of concrete structure can be controlled within 25°C, thereby effectively reducing the constrained deformation stress caused by the temperature difference between the inside and outside of large-volume concrete structures and reducing temperature cracks.

[0053] The hydration heat inhibitor in this embodiment is an organic polyphosphonic acid.

[0054] Organic polyphosphonic acids contain carbon-phosphorus bonds. Compounds with carbon-phosphorus bonds can form stable chelates with various metal ions in concrete under extremely harsh chemical conditions, thereby hindering the metal ions in the concrete from participating in other reactions. Table 4 compares the hydration exothermic characteristics of blank samples without organic polyphosphonic acid, Group A carbon-phosphorus bond samples with organic polyphosphonic acid (containing component A), Group B carbon-phosphorus bond samples with organic polyphosphonic acid (containing component B), and Group C carbon-phosphorus bond samples with organic polyphosphonic acid (containing component C) at an external temperature of 25°C:

[0055] Table 4

[0056]

[0057] Among them, the proportion of organic polyphosphonic acid in the three groups of carbon-phosphorus bond samples in concrete is 0.1%. The phosphonic acid group of the organic polyphosphonic acid in the carbon-phosphorus bond sample in group A is type A, the phosphonic acid group of the organic polyphosphonic acid in the carbon-phosphorus bond sample in group B is type B, and the phosphonic acid group of the organic polyphosphonic acid in the carbon-phosphorus bond sample in group C is type C.

[0058] According to the data in Table 4, the peak exothermicity of the three carbon-phosphorus bond samples decreased by approximately 35% to 45% compared to the blank samples, and the exothermicity peak hysteresis time was approximately 5 to 8 times that of the blank samples. Therefore, organic polyphosphonic acids can effectively inhibit cement hydration in concrete, delaying the peak exothermicity of cement hydration and reducing the peak exothermicity of hydration. This can reduce the total early heat release of cement (by approximately 40% to 50%), thereby fundamentally lowering the hydration temperature rise of concrete and reducing thermal stress.

[0059] In addition, the addition of organic polyphosphonic acid can effectively improve the strength of cement, thereby improving the strength of concrete after solidification. The compressive strength of the above three groups of carbon-phosphorus bond samples can be found in Figure 3 The flexural strength of the three groups of carbon-phosphorus bond samples mentioned above can be found in Figure 4 ,according to Figure 3 and Figure 4 It can be seen that the dosage of hydration heat inhibitor affects the strength of cement mortar in concrete samples after 28 days of curing. Specifically, with increasing dosage, the compressive and flexural strengths of the concrete samples first increase and then decrease. When the dosage of hydration heat inhibitor in concrete is less than 0.15%, the compressive and flexural strengths of the concrete samples are greater than those of the blank samples. The highest strengths are achieved when the dosage is between 0.10% and 0.15%. Therefore, adding an appropriate amount of hydration heat inhibitor can improve the compressive and flexural strengths of concrete.

[0060] Furthermore, in the concrete of the bottom structure 1, the concrete of the middle structure 2 and the concrete of the surface structure 3, fly ash is mixed in the cementitious material of the concrete mixed with the hydration heat inhibitor, and the proportion of fly ash in the cementitious material is not less than 40%.

[0061] It should be noted that existing experimental studies have confirmed that adding large amounts of mineral admixtures to concrete can reduce the hydration temperature rise of concrete. These mineral admixtures, in particular fly ash, can reduce the temperature rise of concrete by 7°C when 30% fly ash is added compared to no fly ash. However, it is common knowledge that fly ash, when added in an amount exceeding 25% of the total cementitious material in concrete, can severely impact the concrete's strength. Therefore, even though large amounts of fly ash can effectively suppress the hydration heat of concrete, its strength-reducing properties make it difficult to apply large amounts of fly ash to the construction of large-volume concrete structures. This is especially true when the proportion of fly ash in the cementitious material exceeds 40%, where the conflicting relationship between fly ash and concrete strength development becomes even more difficult to address.

[0062] Since adding an appropriate amount of hydration heat inhibitor can improve the compressive strength and flexural strength of concrete, this embodiment can increase the fly ash content while ensuring the strength of concrete and effectively reducing the temperature difference between the inside and outside of the concrete structure by adding a hydration heat inhibitor to the concrete. Fly ash has physical properties such as saturation, liquefaction, lubrication and non-plasticity, and the liquefaction of the powder will improve the adhesion of fine materials to coarse particles, improve construction workability, reduce the segregation of aggregates and fine materials, and the liquefaction of the powder can reduce the frictional resistance between particles and improve the performance of pumpable concrete. Therefore, increasing the fly ash content can reduce the difficulty of concrete pumping and improve the performance of concrete. In addition, increasing the fly ash content can also effectively reduce the proportion of other components of cementitious materials in concrete, thereby effectively saving the overall cost of cementitious materials.

[0063] It can be seen that the large-volume concrete structure construction method provided in this embodiment can ensure the strength of the large-volume concrete structure and reduce the temperature difference between the inside and outside of the concrete structure, while making the fly ash content in the large-volume concrete structure reach or even exceed 40%, thereby effectively solving the technical problem of using large-volume fly ash concrete in the construction of large-volume concrete structures.

[0064] In this embodiment, in the concrete of the bottom structure 1, the concrete of the middle structure 2 and the concrete of the surface structure 3, the cementitious material of the concrete mixed with the hydration heat inhibitor may further be mixed with slag powder, and the proportion of slag powder in the cementitious material is not greater than 40%.

[0065] Existing research has shown that when 70% of cement is replaced by finely ground granulated blast furnace slag powder, the hydration heat of the concrete structure will be reduced, but its early tensile and compressive strengths will be greatly reduced. Therefore, the process of suppressing the hydration heat of concrete by adding slag powder to concrete is still difficult to achieve.

[0066] Since the hydration heat inhibitor in this embodiment improves both the compressive strength and the flexural strength of concrete, slag powder can be added to the cementitious material of the concrete containing the hydration heat inhibitor. However, in order to ensure the strength of the concrete, the proportion of slag powder in the cementitious material must not exceed 40%.

[0067] In actual applications, in the concrete of the bottom structure 1, the concrete of the middle structure 2 and the concrete of the surface structure 3, the cementitious material of the concrete mixed with the hydration heat inhibitor may also be mixed with admixtures, and the admixtures include fly ash and slag powder; the proportion of the admixture in the cementitious material is not more than 50%, and the proportion of the fly ash in the admixture is not less than 60%.

[0068] In the large-volume concrete structure construction method provided in this embodiment, when pouring any layer of concrete structure, the pouring of the concrete for the middle structure 2 does not begin before the initial setting time of the concrete for the bottom structure 1; and the pouring of the concrete for the surface structure 3 does not begin before the initial setting time of the concrete for the middle structure 2. This ensures that the upper concrete covering is poured in place before the lower concrete is fully plasticized, which not only helps reduce the temperature rise of the lower concrete but also prevents plastic shrinkage cracks between concrete layers.

[0069] In addition, compared with the construction method of making the construction joint after the lower concrete solidifies and forms, and then pouring the upper concrete, this embodiment can save construction time and improve construction efficiency by ensuring that the start time of pouring the upper concrete does not exceed the initial setting time of the lower concrete.

[0070] Furthermore, the thickness of each layer of the concrete structure is 30-50 cm.

[0071] The thickness of 30-50 cm can not only effectively shorten the interval time between concrete pouring layers, but also facilitate construction workers to carry out construction.

[0072] During pouring, concrete can be distributed from the periphery of each layer toward the center, maintaining a slightly higher level of concrete at the periphery than at the center. Compared to pouring from the center toward the periphery, this method effectively prevents concrete from accumulating in the center and spreading outward, which can lead to segregation of aggregate and paste. This, in turn, prevents weak corners or cracking.

[0073] In addition, by adopting the above-mentioned material distribution method of this embodiment, the final distribution end position can be located at the center of the concrete structure, thereby effectively ensuring the density of the concrete.

[0074] In this embodiment, the concrete of the bottom structure 1 , the concrete of the middle structure 2 , and the concrete of the surface structure 3 may all be mixed with a polycarboxylic acid water reducer.

[0075] Polycarboxylic acid water reducers can effectively reduce the water consumption and water-cement ratio of concrete per cubic meter, thereby improving the workability, strength and durability of concrete construction, extending the retarding time of concrete, delaying and reducing the hydration heat peak, and reducing cold joints in layered construction.

[0076] It should be noted that it is common knowledge that water reducers can reduce the fluidity of cement mortar. However, not all types of water reducers can be used in combination with the organic polyphosphonic acid in this embodiment. In order not to increase the fluidity of cement mortar, this embodiment uses a polycarboxylic acid water reducer in combination with the organic polyphosphonic acid.

[0077] In the large-volume concrete structure construction method provided in this embodiment, when pouring any layer of concrete structure, after pouring the concrete of the surface structure 3, the surface of the surface structure 3 is covered with an insulation layer.

[0078] The addition of a hydration heat inhibitor effectively reduces the peak hydration heat temperature of the surface structure 3, but it also reduces the peak temperature of the concrete in the surface structure 3. During the later stages of the hydration heat, the temperature of the concrete in the surface structure 3 should not drop too quickly; it should cool relatively synchronously with the concrete in the center of the overall concrete structure. Therefore, this embodiment, by covering the surface of the surface structure 3 with an insulating layer, prevents the concrete in the surface structure 3 from being affected by external factors and causing excessive heat dissipation.

[0079] Furthermore, while the surface of the surface structure 3 is covered with an insulation layer, warm water moisturizing curing measures can also be performed on the concrete of the surface structure 3. The use of warm water moisturizing curing measures can not only reduce the temperature difference between the inside and outside of the entire concrete structure, but also allow the cement to hydrate faster.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for constructing a large-volume concrete structure, characterized in that: include: The large-volume concrete structure is divided into multiple layers from bottom to top, and each layer of the concrete structure is divided into a bottom structure (1), a middle structure (2) and a surface structure (3) from bottom to top; A multi-layer concrete structure is cast from bottom to top, and when casting any layer of concrete structure, the concrete of the bottom structure (1), the concrete of the middle structure (2) and the concrete of the surface structure (3) in the layer of concrete structure are cast from bottom to top, and a hydration heat inhibitor is added to at least the concrete of the bottom structure (1) and the concrete of the middle structure (2); the hydration heat inhibitor is used to delay the temperature peak time during the temperature change of the concrete, so that the temperature peak time of the concrete of the bottom structure (1), the temperature peak time of the concrete of the middle structure (2) and the temperature peak time of the concrete of the surface structure (3) are the same; A hydration heat inhibitor is added to the concrete of the surface structure (3), and the amount of the hydration heat inhibitor in the concrete of the bottom structure (1) and the amount of the hydration heat inhibitor in the concrete of the middle structure (2) are both greater than the amount of the hydration heat inhibitor in the concrete of the surface structure (3); The dosage of the hydration heat inhibitor in the concrete of the bottom structure (1) and the dosage of the hydration heat inhibitor in the concrete of the middle structure (2) are both 4.5-4.7‰, and the dosage of the hydration heat inhibitor in the concrete of the surface structure (3) is 0-3.0‰.

2. The method for constructing a large-volume concrete structure according to claim 1, wherein: The hydration heat inhibitor is an organic polyphosphonic acid.

3. The method for constructing a large-volume concrete structure according to claim 2, characterized in that: In the concrete of the bottom structure (1), the concrete of the middle structure (2) and the concrete of the surface structure (3), fly ash is mixed into the cementitious material of the concrete mixed with the hydration heat inhibitor, and the proportion of the fly ash in the cementitious material is not less than 40%.

4. The method for constructing a large-volume concrete structure according to claim 2, characterized in that: In the concrete of the bottom structure (1), the concrete of the middle structure (2) and the concrete of the surface structure (3), the cementitious material of the concrete mixed with the hydration heat inhibitor is mixed with slag powder, and the proportion of the slag powder in the cementitious material is not greater than 40%.

5. The method for constructing a large-volume concrete structure according to claim 1, characterized in that: When pouring any layer of concrete structure, the pouring start time of the concrete of the middle structure (2) does not exceed the initial setting time of the concrete of the bottom structure (1); and the pouring start time of the concrete of the surface structure (3) does not exceed the initial setting time of the concrete of the middle structure (2).

6. The method for constructing a large-volume concrete structure according to claim 5, characterized in that: The thickness of each layer of the concrete structure is 30-50 cm.

7. The method for constructing a large-volume concrete structure according to claim 2, characterized in that: The concrete of the bottom structure (1), the concrete of the middle structure (2) and the concrete of the surface structure (3) are all mixed with a polycarboxylic acid water reducer.

8. The method for constructing a large-volume concrete structure according to claim 1, characterized in that: When pouring any layer of concrete structure, after pouring the concrete of the surface structure (3), the surface of the surface structure (3) is covered with a thermal insulation layer.

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