Super absorbent resin, preparation method thereof and application of super absorbent resin in low-carbon cement

Abstract

The invention discloses a super absorbent resin which comprises the following raw materials in parts by weight: 100 parts of reaction monomers consisting of hydrophilic nonionic monomers and anionic monomers, 0-30 parts of anionic monomers, 0-30 parts of hydrophilic nonionic monomers, 0-30 parts of anionic monomers, 0-30 parts of hydrophilic nonionic monomers, 0-30 parts of hydrophilic nonionic monomers and 0-30 parts of hydrophilic nonionic monomers. 2-8 parts of gamma-cyclodextrine, 0.2-1.5 parts of a cross-linking agent and 0.15-1 part of an initiator. According to the invention, a gel structure with a movable crosslinking point is prepared by utilizing the characteristic of a cyclic structure of gamma-cyclodextrine, and the gel structure is cooperated with a nonionic monomer with a high proportion, so that the shear resistance of the super absorbent resin and the water retention capacity in an LC3 system are improved; no organic solvent is used in the preparation method, polymerization products are not wasted, and the preparation method is green and environment-friendly; through composite use of the super absorbent resin and the calcium oxide expanding agent, self-constriction of the low-carbon cement system concrete is reduced, the crack resistance is improved, the calcium hydroxide content of the system is increased, protection on reinforcing steel bars is improved, and large-scale application and popularization of the low-carbon cementing system in the concrete and building industry are promoted.

Description

Technical Field

[0001] This invention relates to building materials, specifically to a superabsorbent resin, its preparation method, and its application in low-carbon cement. Background Technology

[0002] Concrete is currently the most widely used basic building material in the world. Cement, as the most important binder in concrete, generates a high level of CO2 during its production process. 2 Reduce emissions and decrease CO2 emissions from cementitious material systems. 2 The dosage is key to achieving low-carbon development of concrete. Currently, the internationally used composite cement (LC) is composed of calcined clay (mainly metakaolin), limestone, silicate cement clinker, and gypsum. 3 LC is an important technological approach to achieving low-carbon cement production. Existing research results indicate that, without significantly affecting mechanical properties, LC... 3 Cementitious material systems can reduce cement clinker usage by 50%, effectively reducing carbon emissions from both the cementitious material system and the resulting concrete. However, compared to traditional silicate concrete systems, the use of low-carbon cementitious material systems significantly increases the autogenous shrinkage of concrete and the risk of cracking, making it difficult to apply low-carbon cementitious material systems to large-volume concrete structures with a high risk of cracking. CN118271020A discloses a method for modifying a calcium oxide expansive agent, which reduces the autogenous shrinkage of concrete by adding an expansive agent to a common silicate cement system; CN113105578B discloses a salt-alkali resistant slow-release water-absorbing resin and its application, which reduces the autogenous shrinkage of concrete and reduces early cracking by adding a superabsorbent resin internal curing agent.

[0003] For LC 3 In low-carbon cementitious systems, the hydration rate, hydration products, and rate of decrease in relative humidity within the concrete during hydration differ significantly from those of ordinary silicate concrete systems. Traditional functional materials in LC... 3 The system suffers from insufficient adaptability. CN119751761B discloses an organic-inorganic composite admixture, its preparation method, and its application in a calcined clay-limestone low-carbon cement system. By adjusting the admixture structure, the adsorption effect of the admixture in the layered structure of clay is reduced, thus lowering its sensitivity. CN117105595A discloses a low-carbon engineering cement-based composite material and its preparation method, which utilizes the expansion compensation effect of MgO formed from lightly calcined dolomite to improve LC. 3 The gelling system exhibits good crack resistance, but magnesium oxide suffers from low expansion efficiency. Preparations suitable for LC... 3 The functional additives in the system reduce its autogenous shrinkage and improve its crack resistance, which is to improve LC. 3 The key to the application of low-carbon cementitious systems in mass concrete. Summary of the Invention

[0004] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the purpose of this invention is to provide a superabsorbent resin that can improve shrinkage effect, shear resistance and water retention capacity; another purpose of this invention is to provide a method for preparing a superabsorbent resin that does not use organic solvents, produces no waste and is green and environmentally friendly; this invention also provides an application of superabsorbent resin in low-carbon cement.

[0005] Technical solution: The superabsorbent resin of the present invention comprises 100 parts of reactive monomers composed of hydrophilic nonionic monomers and anionic monomers, wherein the anionic monomers are 0-30 parts; γ-cyclodextrin is 2-8 parts; crosslinking agent is 0.2-1.5 parts; and initiator is 0.15-1 parts.

[0006] Furthermore, the hydrophilic nonionic monomer is acrylamide, methacrylamide, N,N-dimethylacrylamide, or N-isopropylacrylamide; the anionic monomer is one or more of acrylic acid, acrylate, methacrylic acid, or methacrylate.

[0007] Furthermore, the crosslinking agent is a mixture of N,N'-methylenebis(meth)acrylamide and polyethylene glycol diacrylate in a mass ratio of 1 to 2:1, wherein the molecular weight of the polyethylene glycol diacrylate is 400 to 600. Pretreatment with γ-cyclodextrin using a medium molecular weight polyethylene glycol diacrylate can increase the probability of the molecular chains crossing the cyclodextrin.

[0008] Furthermore, the initiator is one or more of potassium persulfate, sodium persulfate, or ammonium persulfate.

[0009] The method for preparing the superabsorbent resin of the present invention includes the following steps:

[0010] (1) Mix γ-cyclodextrin with a cross-linking agent and stir to obtain a 10% mixed solution A;

[0011] (2) Mix the hydrophilic nonionic monomer, anionic monomer, initiator and water evenly to obtain a mixed solution B with a concentration of 30-50%. Then add mixed solution A, mix evenly and react. After drying, crushing and sieving, the superabsorbent resin is obtained.

[0012] Furthermore, in step (1), the stirring temperature is 30-40℃ and the stirring time is 4-6h; in step (2), the reaction temperature is 55-75℃ and the reaction time is 3-5h.

[0013] Furthermore, in step (2), the particle size of the superabsorbent resin after sieving is less than 300 μm.

[0014] The application of the superabsorbent resin described in this invention in a calcined clay-limestone low-carbon cement system.

[0015] Furthermore, a composite additive composed of superabsorbent resin and calcium oxide-based expansive material is used in calcined clay-limestone low-carbon cement systems, wherein the mass ratio of the superabsorbent resin to the calcium oxide-based expansive material is 0.05–0.6:1–6.

[0016] Furthermore, the amount of composite admixture added is 1-10 wt% by mass fraction. Composite admixture can improve its water retention capacity, reduce the effect of autogenous shrinkage, improve its crack resistance, and increase the calcium hydroxide content of the system, thereby improving the protection of the reinforcing steel.

[0017] The preparation principle of this invention is as follows: To improve the shrinkage reduction, shear resistance, and water retention capacity of superabsorbent polymers (SAPs), and to prevent the hydrogel from accelerating water release due to shear breakage during concrete mixing after water absorption, thus failing to provide internal curing and causing fluctuations in concrete workability, thereby reducing its performance and limiting its application in engineering, cyclic dextrin is introduced during the preparation of the SAP. Utilizing its cyclic structure, it can penetrate the molecular chains to form mobile physical cross-linking points. When the gel is sheared and stretched, these cross-linking points can slide, ensuring that multiple molecular chains share the force, thus improving its shear resistance. γ-cyclic dextrin with larger cavities is selected, and medium-molecular-weight polyethylene glycol diacrylate is used for pretreatment with γ-cyclic dextrin to increase the probability of molecular chains penetrating the cyclic dextrin. By reducing the amount of anionic monomers and using a higher content of nonionic monomers, the SAP's performance in LC4 is further improved. 3 Water retention capacity in special porous solution systems; additionally, due to LC 3 The system suffers from reduced alkalinity, insufficient calcium hydroxide, and low relative humidity. Using a combination of superabsorbent resin and calcium oxide-based expansion agent can achieve better shrinkage reduction and crack resistance, and also improve the system's resistance to carbonization.

[0018] Beneficial effects: Compared with the prior art, the present invention has the following significant features:

[0019] (1) γ-Cyclodextrin was introduced into the preparation process of superabsorbent polymer (SAP). Utilizing its cyclic structure, a gel structure with movable crosslinking points was prepared. This, in synergy with a high proportion of nonionic monomers, improved the shear resistance and LC of the SAP. 3 Water retention capacity within the system;

[0020] (2) The preparation method does not use organic solvents. Since the raw materials are all polymerized into products, no waste is generated. The preparation method is green and environmentally friendly.

[0021] (3) By combining superabsorbent resin with calcium oxide-based expanding agents, the carbon dioxide content of low-carbon cement systems (LC) can be reduced. 3 The self-shrinkage of concrete improves its crack resistance, and the increased calcium hydroxide content in the system enhances the protection of steel reinforcement, which is conducive to promoting the large-scale application of low-carbon cementitious systems in the concrete and construction industries. Detailed Implementation

[0022] The present invention will be further described below with reference to specific embodiments.

[0023] Example 1

[0024] A method for preparing a superabsorbent resin includes the following steps:

[0025] (1) Take 4 parts of γ-cyclodextrin, 0.1 parts of N,N'-methylenebis(meth)acrylamide and 0.1 parts of 400 molecular weight polyethylene glycol diacrylate, and stir at 30°C for 6 hours to obtain a 10% mixed solution A;

[0026] (2) Take 70 parts of acrylamide, 15 parts of sodium acrylate, 15 parts of acrylic acid, 0.15 parts of potassium persulfate and water and mix them evenly to obtain a 30% mixed solution B. Then add mixed solution A, mix evenly, place at 55℃ and stir for 5 hours. After drying and pulverizing, pass through a 200μm sieve to obtain a super absorbent resin.

[0027] Application Example 1

[0028] 1.5g of the superabsorbent resin prepared in Example 1 was mixed with 30g of calcium oxide-based expanding agent to obtain a composite admixture, which was then added to 1000g of cementitious mortar for performance evaluation.

[0029] Example 2

[0030] A method for preparing a superabsorbent resin includes the following steps:

[0031] (1) Take 4 parts of γ-cyclodextrin, 0.1 parts of N,N'-methylenebis(meth)acrylamide and 0.1 parts of 500 molecular weight polyethylene glycol diacrylate, and stir at 35°C for 5 hours to obtain a 10% mixed solution A;

[0032] (2) Take 80 parts of acrylamide, 5 parts of methacrylic acid, 15 parts of sodium methacrylate, 0.3 parts of potassium persulfate and water and mix them evenly to obtain a mixed solution B with a concentration of 35%. Then add mixed solution A, mix evenly, place at 65℃ and stir for 4 hours. After drying and pulverizing, pass through a 200μm sieve to obtain superabsorbent resin.

[0033] Application Example 2

[0034] 1.5g of the superabsorbent resin prepared in Example 2 was mixed with 30g of calcium oxide-based expanding agent to obtain a composite admixture, which was then added to 1000g of cementitious mortar for performance evaluation.

[0035] Example 3

[0036] A method for preparing a superabsorbent resin includes the following steps:

[0037] (1) Take 4 parts of γ-cyclodextrin, 0.1 parts of N,N'-methylenebis(meth)acrylamide and 0.1 parts of 600 molecular weight polyethylene glycol diacrylate, and stir at 40°C for 4 hours to obtain a 10% mixed solution A;

[0038] (2) Take 90 parts of acrylamide, 10 parts of sodium acrylate, 0.7 parts of potassium persulfate and water and mix them evenly to obtain a mixed solution B with a concentration of 40%. Then add mixed solution A, mix evenly, place at 75℃ and stir for 3 hours. After drying and pulverizing, pass through a 200μm sieve to obtain superabsorbent resin.

[0039] Application Example 3

[0040] 1.5g of the superabsorbent resin prepared in Example 3 was mixed with 30g of calcium oxide-based expanding agent to obtain a composite admixture, which was then added to 1000g of cementitious mortar for performance evaluation.

[0041] Example 4

[0042] A method for preparing a superabsorbent resin includes the following steps:

[0043] (1) Take 4 parts of γ-cyclodextrin, 0.1 parts of N,N'-methylenebis(meth)acrylamide and 0.1 parts of 600 molecular weight polyethylene glycol diacrylate, and stir at 40°C for 4 hours to obtain a 10% mixed solution A;

[0044] (2) Take 100 parts of acrylamide, 1 part of potassium persulfate and water and mix them evenly to obtain a 50% mixed solution B. Then add mixed solution A, mix evenly, place at 75℃ and stir for 3 hours. After drying and pulverizing, pass through a 200μm sieve to obtain superabsorbent resin.

[0045] Application Example 4

[0046] 1.5g of the superabsorbent resin prepared in Example 4 was mixed with 30g of calcium oxide-based expanding agent to obtain a composite admixture, which was then added to 1000g of cementitious mortar for performance evaluation.

[0047] Example 5

[0048] A method for preparing a superabsorbent resin includes the following steps:

[0049] (1) Take 8 parts of γ-cyclodextrin, 0.8 parts of N,N'-methylenebis(meth)acrylamide and 0.7 parts of 500 molecular weight polyethylene glycol diacrylate, mix them, and stir at 40°C for 4 hours to obtain a 10% mixed solution A.

[0050] (2) Take 90 parts of acrylamide, 10 parts of sodium methacrylate, 0.2 parts of potassium persulfate and water and mix them evenly to obtain a mixed solution B with a concentration of 40%. Then add mixed solution A, mix evenly, place at 75℃ and stir for 3 hours. After drying and pulverizing, pass through a 200μm sieve to obtain superabsorbent resin.

[0051] Application Example 5

[0052] 1.5g of the superabsorbent resin prepared in Example 5 was mixed with 30g of calcium oxide-based expanding agent to obtain a composite admixture, which was then added to 1000g of cementitious mortar for performance evaluation.

[0053] Example 6

[0054] A method for preparing a superabsorbent resin includes the following steps:

[0055] (1) Take 6 parts of γ-cyclodextrin, 0.6 parts of N,N'-methylenebis(meth)acrylamide and 0.3 parts of 500 molecular weight polyethylene glycol diacrylate, and stir at 40°C for 4 hours to obtain a 10% mixed solution A;

[0056] (2) Take 90 parts of acrylamide, 10 parts of acrylic acid, 0.2 parts of potassium persulfate and water and mix them evenly to obtain a mixed solution B with a concentration of 40%. Then add mixed solution A, mix evenly, place at 75℃ and stir for 3 hours. After drying and pulverizing, pass through a 200μm sieve to obtain superabsorbent resin.

[0057] Application Example 6

[0058] Take 1.5g of the superabsorbent resin prepared in Example 6 and mix it with 30g of calcium oxide-based expanding agent to obtain a composite admixture. Add it to 1000g of cementitious mortar for performance evaluation.

[0059] Example 7

[0060] A method for preparing a superabsorbent resin includes the following steps:

[0061] (1) Take 2 parts of γ-cyclodextrin, 0.1 parts of N,N'-methylenebis(meth)acrylamide and 0.1 parts of 500 molecular weight polyethylene glycol diacrylate, and stir at 40°C for 4 hours to obtain a 10% mixed solution A;

[0062] (2) Take 90 parts of acrylamide, 10 parts of sodium acrylate, 0.2 parts of potassium persulfate and water and mix them evenly to obtain a mixed solution B with a concentration of 40%. Then add mixed solution A, mix evenly, place at 75℃ and stir for 3 hours. After drying and pulverizing, pass through a 200μm sieve to obtain superabsorbent resin.

[0063] Application Example 7

[0064] 1.5g of the superabsorbent resin prepared in Example 7 was mixed with 30g of calcium oxide-based expanding agent to obtain a composite admixture, which was then added to 1000g of cementitious mortar for performance evaluation.

[0065] Example 8

[0066] A method for preparing a superabsorbent resin includes the following steps: the remaining steps are the same as in Example 7, except that in step (2), the superabsorbent resin is obtained by drying, pulverizing and sieving through a 100μm sieve.

[0067] Application Example 8

[0068] 1.5g of the superabsorbent resin prepared in Example 8 was mixed with 30g of calcium oxide-based expanding agent to obtain a composite admixture, which was then added to 1000g of cementitious mortar for performance evaluation.

[0069] Example 9

[0070] A method for preparing a superabsorbent resin, the remaining steps are the same as in Example 7, except that in step (2), the superabsorbent resin is obtained by drying, pulverizing and sieving through a 300μm sieve.

[0071] Application Example 9

[0072] Take 1.5g of the superabsorbent resin prepared in Example 9 and mix it with 30g of calcium oxide-based expanding agent to obtain a composite admixture. Add it to 1000g of cementitious mortar for performance evaluation.

[0073] Application Example 10

[0074] A method for preparing a superabsorbent resin, wherein the remaining steps are the same as in Example 9.

[0075] 1g of the superabsorbent resin prepared in Example 10 was mixed with 30g of calcium oxide-based expanding agent to obtain a composite admixture, which was then added to 1000g of cementitious mortar for performance evaluation.

[0076] Application Example 11

[0077] A method for preparing a superabsorbent resin, wherein the remaining steps are the same as in Example 9.

[0078] Take 3g of the superabsorbent resin prepared in Example 11 and mix it with 30g of calcium oxide-based expanding agent to obtain a composite admixture. Add it to 1000g of cementitious mortar for performance evaluation.

[0079] Example 12

[0080] A method for preparing a superabsorbent resin, wherein the remaining steps are the same as in Example 9.

[0081] Application Example 12

[0082] Take 6g of the superabsorbent resin prepared in Example 12 and mix it with 30g of calcium oxide-based expanding agent to obtain a composite admixture. Add it to 1000g of cementitious mortar for performance evaluation.

[0083] Example 13

[0084] A method for preparing a superabsorbent resin, wherein the remaining steps are the same as in Example 11.

[0085] Application Example 13

[0086] Take 3g of the superabsorbent resin prepared in Example 13 and mix it with 60g of calcium oxide-based expanding agent to obtain a composite admixture. Add it to 1000g of cementitious mortar for performance evaluation.

[0087] Example 14

[0088] A method for preparing a superabsorbent resin, wherein the remaining steps are the same as in Example 11.

[0089] Application Example 14

[0090] Take 3g of the superabsorbent resin prepared in Example 14 and mix it with 10g of calcium oxide-based expanding agent to obtain a composite admixture. Add it to 1000g of cementitious mortar for performance evaluation.

[0091] Comparative Example 1

[0092] A method for preparing a superabsorbent resin, the remaining steps are the same as in Example 3, except that γ-cyclodextrin is not used in step (1).

[0093] Application Comparative Example 1

[0094] Take 1.5g of the superabsorbent resin prepared in Comparative Example 1 and add it to 1000g of cementitious mortar for performance evaluation.

[0095] Application Comparative Example 2

[0096] 1.5g of the superabsorbent resin prepared in Comparative Example 1 was mixed with 30g of calcium oxide expanding agent to obtain a composite admixture, which was then added to 1000g of cementitious mortar for performance evaluation.

[0097] Comparative Example 2

[0098] A method for preparing a superabsorbent resin, the remaining steps are the same as in Example 3, except that in step (1), β-cyclodextrin of the same weight is used instead of γ-cyclodextrin.

[0099] Application Comparative Example 3

[0100] Take 1.5g of the superabsorbent resin prepared in Comparative Example 2 and add it to 1000g of cementitious mortar for performance evaluation.

[0101] Application Comparative Example 4

[0102] 1.5g of the superabsorbent resin prepared in Comparative Example 2 was mixed with 30g of calcium oxide expanding agent to obtain a composite admixture, which was then added to 1000g of cementitious mortar for performance evaluation.

[0103] Comparative Example 3

[0104] A method for preparing a superabsorbent resin, the remaining steps are the same as in Example 3, except that in step (1) β-cyclodextrin is used instead of γ-cyclodextrin in the same weight parts, and in step (2) the composition of the reactive ionic monomer is replaced with 10 parts acrylamide and 90 parts sodium acrylate.

[0105] Application Comparative Example 5

[0106] Take 1.5g of the superabsorbent resin prepared in Comparative Example 3 and add it to 1000g of cementitious mortar for performance evaluation.

[0107] Application Comparative Example 6

[0108] 1.5g of the superabsorbent resin prepared in Example 3 was added to 1000g of cementitious mortar for performance evaluation.

[0109] Application Comparative Example 7

[0110] Without adding superabsorbent resin, 30g of calcium oxide expansion agent was added to 1000g of cementitious material for mortar performance evaluation.

[0111] The superabsorbent polymers prepared in the above embodiments and comparative examples are combined with calcium oxide expanding agents to form a composite additive, which is then added to the cementitious system. The effects of the prepared superabsorbent polymers on the calcined clay-limestone low-carbon cement system (LC) are evaluated through self-shrinkage and workability. 3The effects of these additives on crack resistance and workability were investigated. The cementitious system consisted of 30 parts calcined clay, 20 parts limestone, and 50 parts reference cement. The proportions and testing methods were in accordance with JC / T 2551-2019. The reference mortar had a water-cement ratio of 0.35 and a mortar-cement ratio of 1:2. For examples and comparative examples containing superabsorbent polymers, the amount of water added was increased by 10 times the mass of the dry superabsorbent polymer. For example, if 1.5g of superabsorbent polymer was added, the amount of water added would increase by 15g. The performance of the composite admixture was evaluated using the self-shrinkage ratio and the fluidity ratio.

[0112] Table 1. Effects of composite admixtures on mortar autogenous shrinkage and fluidity.

[0113] Self-shrinkage ratio / % Flowability ratio / % Application Example 1 -329 65 Application Example 2 -324 72 Application Example 3 -318 86 Application Example 4 -271 92 Application Example 5 -282 96 Application Example 6 -291 90 Application Example 7 -306 75 Application Example 8 -276 71 Application Example 9 -365 79 Application Example 10 -341 81 Application Example 11 -365 74 Application Example 12 -459 69 Application Example 13 -635 75 Application Example 14 -265 74 Application Comparative Example 1 24 71 Application Comparative Example 2 -194 72 Application Comparative Example 3 6 74 Application Comparative Example 4 -224 76 Application Comparative Example 5 38 46 Application Comparative Example 6 -53 82 Application Comparative Example 7 -176 102

[0114] The test results according to JC / T 2551-2019 are shown in Table 1. A negative self-shrinkage ratio indicates that the mortar expanded after addition. The larger the absolute value of this ratio, the greater the expansion. A positive ratio indicates that it only reduces self-shrinkage. It can be seen that the addition of superabsorbent polymer (SAP) generally leads to a decrease in fluidity due to the reduction of mixing water caused by water absorption. However, adjusting the monomer type, crosslinking agent, and using cyclodextrin can mitigate its impact on fluidity. Using an expansion agent alone can also reduce self-shrinkage, but the combined use of SAP and an expansion agent significantly improves the shrinkage reduction effect. Using larger-ring γ-cyclodextrin can more effectively enhance the water-holding capacity of SAP, thus enhancing its shrinkage reduction effect.

Claims

1. A superabsorbent resin, characterized in that: The raw materials include the following parts by weight: 100 parts of reactive monomers composed of hydrophilic nonionic monomers and anionic monomers, of which 0-30 parts are anionic monomers; 2-8 parts are γ-cyclodextrin; 0.2-1.5 parts are crosslinking agents; and 0.15-1 parts are initiators.

2. The superabsorbent resin according to claim 1, characterized in that: The hydrophilic nonionic monomer is acrylamide, methacrylamide, N,N-dimethylacrylamide, or N-isopropylacrylamide; the anionic monomer is one or more of acrylic acid, acrylate, methacrylic acid, or methacrylate.

3. The superabsorbent resin according to claim 1, characterized in that: The crosslinking agent is a mixture of N,N'-methylenebis(meth)acrylamide and polyethylene glycol diacrylate in a mass ratio of 1 to 2:1, wherein the molecular weight of the polyethylene glycol diacrylate is 400 to 600.

4. The superabsorbent resin according to claim 1, characterized in that: The initiator is one or more of potassium persulfate, sodium persulfate, or ammonium persulfate.

5. A method for preparing the superabsorbent resin according to claim 1, characterized in that, Includes the following steps: (1) Mix γ-cyclodextrin with a cross-linking agent and stir to obtain a 10% mixed solution A; (2) Mix the hydrophilic nonionic monomer, anionic monomer, initiator and water evenly to obtain a mixed solution B with a concentration of 30-50%. Then add mixed solution A, mix evenly and react. After drying, crushing and sieving, the superabsorbent resin is obtained.

6. The method for preparing the superabsorbent resin according to claim 5, characterized in that: In step (1), the stirring temperature is 30-40℃ and the stirring time is 4-6h; in step (2), the reaction temperature is 55-75℃ and the reaction time is 3-5h.

7. The method for preparing the superabsorbent resin according to claim 5, characterized in that: In step (2), the particle size of the superabsorbent resin after sieving is less than 300 μm.

8. The application of the superabsorbent resin according to claim 1 in a calcined clay-limestone low-carbon cement system.

9. The application of the superabsorbent resin according to claim 8 in the calcined clay-limestone low-carbon cement system, characterized in that: The superabsorbent resin and calcium oxide-based expansive material are mixed to form a composite additive used in calcined clay-limestone low-carbon cement systems, wherein the mass ratio of the superabsorbent resin and calcium oxide-based expansive material is 0.05-0.6:1-6.

10. The application of the superabsorbent resin according to claim 8 in the calcined clay-limestone low-carbon cement system, characterized in that: The amount of the composite admixture added is 1 to 10 wt% by mass fraction.