Carbon sequestration type concrete internal curing material based on NaX molecular sieve and preparation method of carbon sequestration type concrete internal curing material

Abstract

The invention discloses a carbon sequestration type concrete internal curing material based on a NaX molecular sieve and a preparation method of the carbon sequestration type concrete internal curing material, and belongs to the technical field of building materials. The invention discloses a preparation method of a medicine. The molecular sieve adsorbent is prepared from the following raw materials: 15%-18% of a NaX molecular sieve, 8%-10% of carboxymethyl cellulose, 6%-8% of bagasse cellulose, 5%-10% of polyvinyl alcohol, 24%-30% of N-hydroxymethyl acrylamide, 10%-15% of maleic anhydride, 3%-4% of xanthan gum, 2%-3% of calcium silicate, 8%-10% of pentaerythritol allyl ether, 10%-13% of allyl alcohol polyoxyethylene ether, 0.15%-0.2% of glycerol dimethacrylate and 0.2%-0.2% of glycerol dimethacrylate. The water-based adhesive comprises the following components in percentage by weight: 0.4% of triethylene glycol dimethacrylate, 0.3%-0.7% of diallyldimethylammonium chloride, 0.08%-0.5% of ammonium sulfite and 1%-3% of ammonia water. The concrete internal curing material with the CO2 capturing and sealing functions is developed, the good alkali absorption characteristic is shown, the mechanical property of concrete is improved, meanwhile, carbon sequestration curing and carbon sequestration service are achieved in the concrete internal curing process and the service process, and a novel carbon sequestration mode of CO2 capturing, curing and sealing in the building field is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and particularly relates to a carbon-fixing concrete internal curing material based on NaX molecular sieve and a preparation method thereof. Background Art

[0002] High-performance concrete, characterized by low water-cement ratio and high content of ultrafine mineral powder, is widely used in roads, bridges, dams, industries and various housing structures due to its excellent mechanical properties and durability. However, while high-performance concrete achieves high strength, low porosity and high impermeability, it also greatly increases the risk of concrete cracking. On the one hand, due to the low water-cement ratio, the internal water of the concrete is consumed quickly; on the other hand, as the density of the concrete structure increases, it is difficult for external curing water to enter its interior, and the water required for later hydration cannot be replenished, which intensifies the self-drying phenomenon inside the cement stone, resulting in excessive shrinkage and cracking. And as the strength of concrete gradually increases, its tendency to shrinkage cracking becomes more obvious.

[0003] In recent years, internal curing has become the most effective means of curing high-performance concrete, and it is also one of the most effective methods to alleviate concrete self-drying and shrinkage cracking. At the same time, this method is simple in process and easy to operate. It can eliminate processes such as film covering, demolding, and repeated watering without adding equipment and process links, and replace traditional curing processes such as watering, spraying, water surrounding, covering, and film covering, thereby improving construction efficiency. Internal curing technology refers to the introduction of internal curing materials into cement-based materials. As the hydration of cement-based materials proceeds, the internal humidity decreases, and the ion concentration or pH increases, the internal curing materials can release moisture. This part of the internal curing material entrained with water will inevitably supplement the internal humidity of the cement-based material, reduce the shrinkage of the cement-based material, optimize the structure of the hydration product, and improve durability.

[0004] There are unresolved technical problems in the application of existing internal curing materials, which have an adverse effect on the rheological properties and mechanical properties of cement-based composite materials. Among them, the influence on rheological properties is mainly manifested in: SAP is added to concrete because of its low water absorption rate and poor water retention in the alkaline environment of concrete, which makes it easy for the internal curing material to fail to fully and effectively provide the moisture required for the coagulation and hardening of concrete, release moisture prematurely, and have low internal curing efficiency, thereby affecting the workability and mechanical properties of concrete. In addition, most of the existing preparations of concrete internal curing materials are focused on the design and synthesis for the purpose of improving the curing efficiency of concrete, and rarely design, prepare and apply concrete internal curing materials from the perspective of green carbon reduction such as CO2 capture and carbon solidification. Carbon fixation internal curing of cement-based materials intervenes in the concrete curing stage, absorbing and solidifying CO2 while promoting the coagulation and hardening process of concrete.

[0005] Therefore, while improving the water absorption of existing internal curing materials in alkaline environments, maximizing or offsetting CO2 emissions during the production stage, thereby reducing carbon emissions throughout the entire life cycle of cement products and promoting the development of green and low-carbon applications in building construction, is a new idea for low-carbon applications of concrete in the construction industry. Summary of the invention

[0006] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a carbon-fixing concrete internal curing material based on NaX molecular sieve and a preparation method thereof, so as to solve the technical problems that the existing internal curing materials have low liquid absorption rate in alkaline environment and poor effect on the mechanical properties of concrete. The present invention develops a concrete internal curing material with CO2 capture and storage function, which not only exhibits good alkali absorption characteristics and improves the mechanical properties of concrete, but also realizes carbon fixation curing and carbon fixation service during the concrete internal curing process and service process, realizes a new carbon fixation mode in the construction field of CO2 capture-solidification-storage, provides a basis for carbon reduction technology in the construction field, contributes to the promotion and use of carbon reduction technology, further promotes the development of low-carbon buildings, and provides a research basis for building carbon emission reduction.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The invention provides a NaX molecular sieve-based carbon-fixing concrete internal curing material, which is prepared from the following raw materials by weight: 15% to 18% of NaX molecular sieve, 8% to 10% of carboxymethyl cellulose, 6% to 8% of bagasse cellulose, 5% to 10% of polyvinyl alcohol, 24% to 30% of N-hydroxymethyl acrylamide, 10% to 15% of maleic anhydride, 3% to 4% of xanthan gum, 2% to 3% of calcium silicate, 8% to 10% of pentaerythritol allyl ether, 10% to 13% of polyoxyethylene propylene alcohol ether, 0.15% to 0.2% of dimethacrylate glyceride, 0.2% to 0.4% of triethylene glycol dimethacrylate, 0.3% to 0.7% of diallyl dimethyl ammonium chloride, 0.08% to 0.5% of ammonium sulfite and 1% to 3% of aqueous ammonia.

[0009] In one embodiment, the SiO2 / CaO content ratio in the calcium silicate is 0.99 to 1.15, the sulfate content is less than 0.05%, and the chloride content is less than 0.03%;

[0010] The carboxymethyl cellulose is food grade, and the content is ≥95%.

[0011] In one embodiment, the NaX molecular sieve is prepared from the following raw materials: diatomaceous earth, kaolin, NaX molecular sieve seed crystals, sodium hydroxide, silica sol, and deionized water;

[0012] The process of preparing NaX molecular sieve is as follows:

[0013] Diatomaceous earth, kaolin, sodium hydroxide and silica sol are sequentially added into deionized water for dispersion and dissolution, and then ultrasonically dispersed to prepare suspension A;

[0014] NaX molecular sieve seed crystals were added to suspension A, argon was passed through, and magnetic stirring was performed in a water bath at 25±2°C to obtain a mixed solution B with a mass concentration of 3%;

[0015] The mixed solution B is sealed and then gelled and crystallized in sequence. The obtained product is cooled to room temperature, washed to neutrality, dried, and ground to obtain NaX molecular sieve.

[0016] In one embodiment, the mass ratio of diatomaceous earth, kaolin, sodium hydroxide, silica sol, and deionized water is 3:1:4:16:800.

[0017] In one embodiment, the diatomaceous earth has a particle size of 325 mesh, an Al2O3 content of 5.2%, a Fe2O3 content of 1.2%, a pH value of 6 to 8, and a pore volume of 0.45 to 0.98 cm 3 / g, specific surface area is 40~65㎡ / g, adsorption rate ≥300%;

[0018] The kaolin has a particle size of 800-1500 mesh, an active ingredient content of ≥60%, a silicon dioxide content of ≥50%, and a Mohs hardness of 3-5;

[0019] The silica sol is a transparent or translucent liquid, the mass fraction of SiO2 in the silica sol is ≥30%, and the pH value is 9-11.

[0020] In one embodiment, the mixed liquid B is transferred to a polymerization reactor and sealed, the microwave power during gelation is 120 W, and the gelation time is 20 to 60 min; the microwave power during crystallization is 700 W, and the crystallization time is 60 to 120 min.

[0021] The present invention also provides a method for preparing a carbon-fixing concrete internal curing material based on NaX molecular sieve, comprising the following steps:

[0022] Preparation of NaX molecular sieves;

[0023] Dispersing carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate in deionized water to prepare a mixed solution C;

[0024] Maleic anhydride is prepared into a dilute maleic anhydride solution with deionized water, and then ammonia water is added to neutralize it, and then N-hydroxymethyl acrylamide, pentaerythritol allyl ether and polyoxyethylene propenol ether are added to prepare a mixture D;

[0025] Dispersing dimethacrylate glycerol, triethylene glycol dimethacrylate and diallyl dimethyl ammonium chloride in deionized water in sequence to prepare a mixed solution E;

[0026] Sorbitan tristearate and cyclohexane are stirred and mixed to form an oil phase;

[0027] Adding NaX molecular sieves to the oil phase, stirring and mixing in a constant temperature water bath, and adding the prepared mixed solution C and polyvinyl alcohol during the stirring and mixing process and continuing to stir to prepare a mixed solution F;

[0028] The mixture D is added dropwise to the mixed solution F, and then the mixed solution E is added, and after a set time, ammonium sulfite is added to carry out a graft polymerization reaction to obtain a composite G;

[0029] The composite G is immersed and cleaned to prepare a carbon-fixing concrete internal curing material based on NaX molecular sieve.

[0030] In one embodiment, the mass concentration of the mixed solution C is 1%; the mass concentration of the maleic anhydride dilute solution is 13%; and the mass concentration of the mixed solution E is 10%.

[0031] In one embodiment, the sorbitan tristearate and cyclohexane are mechanically stirred for 20 to 50 minutes in a water bath at 40 to 45° C. to form an oil phase;

[0032] The sorbitan tristearate is 1% to 5% of the mass fraction of cyclohexane, and the volume ratio of the oil phase to the water phase is 3 to 5:1, wherein the volume of the water phase is the total volume of the mixed solution C (a deionized water solution of carboxymethyl cellulose, bagasse cellulose, xanthan gum, and calcium silicate), the mixed solution D (a water solution of maleic anhydride, ammonia water, N-hydroxymethyl acrylamide, pentaerythritol allyl ether and polyoxyethylene propenyl alcohol ether), and the mixed solution E (a deionized water solution of dimethacrylate glyceride, triethylene glycol dimethacrylate and diallyl dimethyl ammonium chloride).

[0033] In one embodiment, the set time is 30 minutes, the reaction temperature of the graft polymerization reaction is 40-50°C, the graft polymerization reaction is carried out under argon conditions, the rotation speed of more than 200r / min is maintained during the graft polymerization reaction, and the time of the graft polymerization reaction is 3-4h.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The present invention provides a carbon-fixing concrete internal curing material based on NaX molecular sieve. First, the material contains a NaX molecular sieve component. NaX can not only selectively absorb CO2, but also has a good adsorption capacity. The absorbed and captured CO2 is carbon-fixed and cured in the internal curing material as the internal curing material continuously releases water during the internal curing process, thereby realizing a new carbon-fixing model in the construction field of capturing, solidifying and sealing CO2 during the concrete preparation process. The material intervenes in the concrete curing stage, absorbs and solidifies CO2, and promotes the coagulation and hardening process of concrete. The CO2 emitted in the production stage is reduced or offset to the maximum extent. The material has a significant improvement effect on the mechanical properties and deformation resistance of concrete, and can also be used as an auxiliary material and filling material for the rigid skeleton of the internal curing material, which can significantly improve the hardness and water retention of the internal curing gel. In addition, in the later service process of concrete, the NaX molecular sieve can continue to absorb CO2 to exert its carbon fixation effect. Furthermore, diatomaceous earth and kaolin are introduced into the NaX molecular sieve, which greatly reduces the cost of the NaX molecular sieve. At the same time, the invented concrete curing material is green, environmentally friendly and high-strength.

[0036] Secondly, the bagasse cellulose in the material contains a large number of hydroxyl groups in its structure, which can be used together with carboxymethyl cellulose as the organic three-dimensional skeleton of the NaX molecular sieve carbon-fixing concrete internal curing water-retaining material, ensuring that the organic monomer can fully undergo graft copolymerization reaction. The main monomer component N-hydroxymethyl acrylamide is a non-ionic monomer with good salt and alkali resistance. The NaX molecular sieve skeleton can be continuously filled through polymerization reaction, which can significantly improve the liquid absorption rate and water retention performance of the internal curing material. In addition, the relatively excellent salt and alkali resistance can more effectively adjust the humidity distribution inside the concrete to a certain extent, and ensure the internal curing efficiency of the internal curing material in the alkaline environment of the concrete and other saline-alkali media. Therefore, the NaX molecular sieve carbon-fixing concrete internal curing water-retaining material prepared by the present invention has good liquid absorption-liquid storage-water retention performance while achieving efficient carbon fixation.

[0037] Finally, the material contains calcium silicate, which is the main component of concrete and is easy to carbonize. It has great potential to absorb and store CO2 in the atmosphere, and can give the internal curing material good carbon fixation during the setting and hardening process of concrete and even in the service stage. In addition, calcium silicate can provide the initial rigid skeleton of the NaX molecular sieve carbon fixation type concrete internal curing water retention material, and the large number of internal pores also provide attachment points for organic monomers during the polymerization process; the composite between inorganic materials and organic monomers increases the three-dimensional network density of the internal curing material, thereby making the NaX molecular sieve carbon fixation type concrete internal curing water retention material formed after the end present good water retention performance, and the slow release of water inside the internal curing material replenishes the water consumption of the concrete, controls and reduces the shrinkage of the concrete, and ensures that the concrete material is fully hydrated; in addition, a certain amount of calcium silicate dispersed in the internal curing material is of great significance to reducing the shrinkage deformation of concrete and improving its mechanical properties during the internal curing process of concrete.

[0038] Furthermore, NaX molecular sieve, as a solid adsorption material, is an aluminosilicate compound with excellent thermal stability, ion exchangeability, selectivity, high specific surface area and other characteristics. Because its molecular sieve has its unique pore size, it can be used to have a large adsorption capacity for CO2 and water. The present invention uses diatomaceous earth and kaolin as raw materials for NaX molecular sieve, which significantly reduces the cost of NaX molecular sieve. Introducing NaX molecular sieve into the interior of concrete curing materials can give the curing materials good CO2 capture performance, and play a carbon fixation curing and carbon fixation service effect in concrete, while improving the mechanical properties and durability of concrete and promoting the development of low-carbon buildings.

[0039] Furthermore, the three-dimensional structure of sugarcane bagasse cellulose contains a large number of hydrophilic groups such as hydroxyl and carboxyl groups, which have strong water absorption and good salt resistance. Introducing it into concrete curing materials to prepare functional composite highly absorbent grease not only has economic value and promotes regional economic development, but also has environmental significance and provides new ideas for the comprehensive utilization of bagasse.

[0040] Furthermore, xanthan gum is a white powder, a polysaccharide polymer compound, showing a rigid and orderly rod-shaped double helix structure, and its molecular weight is generally between 2×10 6 ~5×10 7 It is slightly odorous, easily soluble in water, and its aqueous solution is neutral. Its molecular formula is (C 35 H 49 O 29 ) n , purity ≥99%, adding water to form a viscous, transparent or slightly milky, easy-flowing solution, with good salt and alkali resistance, can provide an organic cross-linked skeleton for carbon-fixing concrete internal curing materials, and ensure that the internal curing materials have good applicability and stability in the alkaline environment of concrete. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0042] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0043] Herein, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0044] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0045] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0046] The invention provides a NaX molecular sieve-based carbon-fixing concrete internal curing material and a preparation method thereof.

[0047] Among them, the first aspect provides a carbon-fixing concrete internal curing material based on NaX molecular sieve, which is composed of the following raw materials: NaX molecular sieve, carboxymethyl cellulose, bagasse cellulose, polyvinyl alcohol, N-hydroxymethyl acrylamide, maleic anhydride, xanthan gum, calcium silicate, pentaerythritol allyl ether (PTAE), acryl alcohol polyoxyethylene ether (APEG), dimethacrylate glycerol (GDA), triethylene glycol dimethacrylate (TEGDMA), diallyl dimethyl ammonium chloride (DMDAAC), ammonium sulfite, ammonia water, cyclohexane, isopropyl alcohol, and sorbitan tristearate (Span-65).

[0048] Specifically, it is prepared from the following raw materials by weight:

[0049] 15% to 18% NaX molecular sieve, 8% to 10% carboxymethyl cellulose, 6% to 8% bagasse cellulose, 5% to 10% polyvinyl alcohol, 24% to 30% N-hydroxymethyl acrylamide, 10% to 15% maleic anhydride, 3% to 4% xanthan gum, 2% to 3% calcium silicate, 8% to 10% pentaerythritol allyl ether (PTAE), 10% to 13% acryl alcohol polyoxyethylene ether (APEG), 0.15% to 0.2% glyceryl dimethacrylate (GDA), 0.2% to 0.4% triethylene glycol dimethacrylate (TEGDMA), 0.3% to 0.7% diallyl dimethyl ammonium chloride (DMDAAC), 0.08% to 0.5% ammonium sulfite, and 1% to 3% aqueous ammonia.

[0050] Among them, calcium silicate is chemically pure, white powder, SiO2 / CaO content ratio is 0.99-1.15, sulfate content is less than 0.05%, and chloride content is less than 0.03%.

[0051] Carboxymethyl cellulose is food grade, white solid, and its content is ≥95%.

[0052] The above-mentioned NaX molecular sieve material comprises the following raw materials: diatomaceous earth, kaolin, NaX molecular sieve seed crystals, sodium hydroxide, silica sol, and deionized water;

[0053] The preparation process of the NaX molecular sieve material is as follows:

[0054] Diatomaceous earth, kaolin, sodium hydroxide and silica sol are sequentially added into deionized water for dispersion and dissolution, and then ultrasonically dispersed to prepare suspension A;

[0055] NaX molecular sieve seed crystals were added to suspension A, argon was passed through, and magnetic stirring was performed in a water bath at 25±2°C to obtain a mixed solution B with a mass concentration of 3%;

[0056] The mixed solution B is sealed and then gelled and crystallized in sequence. The obtained product is cooled to room temperature, washed to neutrality, dried, and ground to obtain NaX molecular sieve.

[0057] The specific steps are as follows:

[0058] Step 1: slowly add the weighed diatomaceous earth, kaolin, sodium hydroxide and silica sol into deionized water in sequence (mass ratio is diatomaceous earth: kaolin: sodium hydroxide: silica sol: deionized water = 3:1:4:16:800) to dissolve or disperse, and ultrasonically disperse for 30 minutes to obtain suspension A;

[0059] Step 2: Slowly add the weighed NaX molecular sieve seed crystals into the suspension A, pass argon, and stir with a constant temperature magnetic force at a water bath temperature of 25±2°C for 4 to 8 hours to obtain a mixed solution B with a mass concentration of 3%;

[0060] Step 3: Transfer the mixed liquid B to a sealed polymerization reactor, and gelatinize for 20 to 60 minutes at a microwave power of 120 W. Subsequently, increase the microwave power to 700 W and crystallize for 60 to 120 minutes. Cool the obtained product to room temperature, wash it repeatedly with distilled water until it is neutral, dry it in a vacuum oven at 60° C. for 24 hours, and then grind it to obtain the NaX molecular sieve material.

[0061] The particle size of diatomite is 325 mesh, the Al2O3 content is 5.2%, the Fe2O3 content is 1.2%, the pH value is 6-8, and the pore volume is 0.45-0.98cm 3 / g, specific surface area is 40~65㎡ / g, adsorption rate is ≥300%.

[0062] The particle size of kaolin is 800-1500 mesh, the content of effective ingredients is ≥60%, the content of silicon dioxide is ≥50%, and the Mohs hardness is 3-5.

[0063] Sodium hydroxide is analytically pure, with a content of ≥96%.

[0064] Silica sol is a transparent or translucent liquid with a SiO2 mass fraction of ≥30% and a pH value of 9 to 11.

[0065] The present invention also provides a method for preparing a carbon-fixing concrete internal curing material based on NaX molecular sieve, the method adopts the above-mentioned formula for preparing the carbon-fixing concrete internal curing material based on concrete NaX molecular sieve, and the method comprises the following steps:

[0066] Step 1: Weigh the above raw materials by mass;

[0067] Step 2: Slowly add the weighed diatomaceous earth, kaolin, sodium hydroxide and silica sol into deionized water in sequence (mass ratio is diatomaceous earth: kaolin: sodium hydroxide: silica sol: deionized water = 3:1:4:16:800) to dissolve or disperse, and ultrasonically disperse for 30 minutes to obtain suspension A;

[0068] Step 3: Slowly add NaX molecular sieve seed crystals to suspension A, pass argon, and stir with constant temperature magnetic force at a water bath temperature of 25±2°C for 4 to 8 hours to obtain a mixed solution B with a mass concentration of 3%;

[0069] Step 4: Transfer the mixed solution B to a sealed polymerization reactor, and perform gelation at a microwave power of 120 W for 20 to 60 min. Subsequently, increase the microwave power to 700 W, and perform crystallization for 60 to 120 min. The obtained product is cooled to room temperature, repeatedly washed with distilled water until neutral, dried in a vacuum oven at 60° C. for 24 h, and then ground to obtain a NaX molecular sieve material.

[0070] Step 5: The weighed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate are slowly and evenly dispersed in deionized water in sequence, and magnetically stirred for 30 minutes to prepare a mixed solution C with a mass concentration of 1%;

[0071] Step 6: Prepare a 13% dilute solution of maleic anhydride with deionized water, start stirring, and heat to 40° C. After complete dissolution, wait until the temperature drops to room temperature, drop weighed ammonia water, and after neutralization, add weighed N-hydroxymethyl acrylamide, pentaerythritol allyl ether (PTAE) and acryl alcohol polyoxyethylene ether (APEG) to obtain a mixture D, and transfer it into a brown bottle, protect from light, and set aside;

[0072] Step 7: Disperse the weighed glycerol dimethacrylate (GDA), triethylene glycol dimethacrylate (TEGDMA) and diallyl dimethyl ammonium chloride (DMDAAC) in deionized water in sequence, stir magnetically for 30 minutes, and prepare a mixed solution E with a concentration of 10%;

[0073] Step 8: Mechanically stir the weighed sorbitan tristearate (Span-65) and cyclohexane in a water bath at 40-45° C. for 20-50 minutes to form an oil phase after the two are completely mixed;

[0074] Step 9: Slowly add the pre-obtained NaX molecular sieve to the oil phase, pass nitrogen, stir at 300 r / min for 30 min in a constant temperature water bath environment of 30-45° C., and slowly add the pre-mixed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate mixed solution C and polyvinyl alcohol in the process of continuous stirring; continue stirring for 30 min to obtain a mixed solution F;

[0075] Step 10: slowly drop the mixture D into the mixed solution F for 1 h to 4 h. After the dropwise addition, add the mixed solution E into a four-necked flask. After 30 min, add the weighed ammonium sulfite. The temperature is controlled between 40°C and 50°C during the whole process. Pass argon gas and keep stirring (speed> 200 r / min). After reacting for 3 h to 4 h, obtain the complex G.

[0076] Step 11: Take out the composite G, soak and wash it with isopropanol for 3 to 5 times, and obtain the NaX molecular sieve-based carbon-fixing concrete internal curing material after no isopropanol evaporates.

[0077] Wherein, in step eight, sorbitan tristearate (Span-65) and cyclohexane are mechanically stirred and mixed completely under 40-45° C. water bath conditions to form an oil phase, sorbitan tristearate (Span-65) is 1% to 5% of the mass fraction of cyclohexane, and the volume ratio of the oil phase to the water phase is 3 to 5:1, wherein the volume of the water phase is the total volume of the mixed solution C (deionized aqueous solution of carboxymethyl cellulose, bagasse cellulose, xanthan gum, and calcium silicate), the mixture D (aqueous solution of maleic anhydride, ammonia water, N-hydroxymethyl acrylamide, pentaerythritol allyl ether and polyoxyethylene propenol ether), and the mixed solution E (deionized aqueous solution of dimethacrylate glyceride, triethylene glycol dimethacrylate and diallyl dimethyl ammonium chloride).

[0078] The invention firstly uses diatomite, kaolin, sodium hydroxide, silica sol and NaX molecular sieve crystal seeds to prepare NaX molecular sieve material, then uses carboxymethyl cellulose, bagasse cellulose and polyvinyl alcohol as graft skeletons, and organic monomers such as N-hydroxymethyl acrylamide and maleic anhydride are continuously grafted and polymerized under the action of an initiator and a crosslinking agent, and the NaX molecular sieve material and calcium silicate are also continuously involved in the graft polymerization of the organic network structure of the internal curing material and perform a filling effect in the process, and after the reaction is completed, the product is dehydrated, dried and screened by isopropanol to obtain the long-acting salt-alkali resistant internal curing water-retaining material.

[0079] The salt-alkali resistance of the NaX molecular sieve-based carbon-fixing concrete curing and water-retaining material prepared by the present invention is improved, and the compressive strength and shrinkage reduction performance of the concrete are significantly improved. The 28d compressive strength of the concrete is more than 110% of the strength of the benchmark concrete, and the shrinkage ratio is less than 40%. In addition, it also exhibits excellent CO2 adsorption.

[0080] In summary, the present invention provides a carbon-fixing concrete curing material based on NaX molecular sieve and a preparation method thereof, designs concrete materials, and improves the carbon fixation potential of concrete. In addition, a specific method suitable for carbon fixation curing technology is developed to improve the carbon fixation efficiency of the curing process and the later concrete coagulation and oxidation process. Therefore, the present invention has developed a concrete curing material with CO2 capture-solidification-storage performance, which can significantly reduce concrete shrinkage and improve mechanical properties. It can solidify CO2 while fully compensating for the internal moisture of concrete to promote hydration and reduce shrinkage deformation, promote green and sustainable development of buildings, contribute to the promotion and use of carbon reduction technologies, further promote the development of low-carbon concrete buildings, and provide a research basis for building carbon emission reduction.

[0081] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0082] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0083] Embodiment 1:

[0084] This example provides a method for preparing a carbon-fixing concrete internal curing material based on NaX molecular sieve, which is composed of the following raw materials by weight: 15% NaX molecular sieve, 8% carboxymethyl cellulose, 6% bagasse cellulose, 5% polyvinyl alcohol, 30% N-hydroxymethyl acrylamide, 10% maleic anhydride, 3% xanthan gum, 2% calcium silicate, 8% pentaerythritol allyl ether (PTAE), 10% acryl alcohol polyoxyethylene ether (APEG), 0.15% dimethacrylate glycerol (GDA), 0.27% triethylene glycol dimethacrylate (TEGDMA), 0.5% diallyl dimethyl ammonium chloride (DMDAAC), 0.08% ammonium sulfite, and 2% ammonia water.

[0085] The preparation method of the above-mentioned NaX molecular sieve-based carbon-fixing concrete internal curing material comprises the following steps:

[0086] Step 1: Weigh the above raw materials by mass;

[0087] Step 2: Slowly add the weighed diatomaceous earth, kaolin, sodium hydroxide and silica sol into deionized water in sequence (mass ratio is diatomaceous earth: kaolin: sodium hydroxide: silica sol: deionized water = 3:1:4:16:800) to dissolve or disperse, and ultrasonically disperse for 30 minutes to obtain suspension A;

[0088] Step 3: Slowly add the weighed NaX molecular sieve seed crystals into the suspension A, pass argon, and stir with a constant temperature magnetic stirrer at a water bath temperature of 25±2°C for 6 hours to obtain a mixed solution B with a mass concentration of 3%;

[0089] Step 4: Transfer the mixed solution B to a sealed polymerization reactor, and perform gelation for 50 min at a microwave power of 120 W. Subsequently, increase the microwave power to 700 W and perform crystallization for 100 min. Cool the obtained product to room temperature, wash it repeatedly with distilled water until it is neutral, dry it in a vacuum oven at 60° C. for 24 h, and then grind it to obtain a NaX molecular sieve material.

[0090] Step 5: Slowly and evenly disperse the weighed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate in deionized water in turn, stir magnetically for 30 minutes, and prepare a mixed solution C with a mass concentration of 1%;

[0091] Step 6: Prepare a 13% dilute solution of maleic anhydride with deionized water, start stirring, and heat to 40° C. After complete dissolution, wait until the temperature drops to room temperature, drop weighed ammonia water, and after neutralization, add weighed N-hydroxymethyl acrylamide, pentaerythritol allyl ether (PTAE) and acryl alcohol polyoxyethylene ether (APEG) to obtain a mixture D, and transfer it into a brown bottle, protect from light, and set aside;

[0092] Step 7: Disperse the weighed glycerol dimethacrylate (GDA), triethylene glycol dimethacrylate (TEGDMA) and diallyl dimethyl ammonium chloride (DMDAAC) in deionized water in sequence, stir magnetically for 30 minutes, and prepare a mixed solution E with a concentration of 10%;

[0093] Step 8: Mechanically stir the weighed sorbitan tristearate (Span-65) and cyclohexane in a 45° C. water bath for 40 minutes to form an oil phase after the two are completely mixed;

[0094] Step 9: Slowly add the pre-obtained NaX molecular sieve to the oil phase, pass nitrogen, stir at 300 r / min for 30 min in a constant temperature water bath at 40°C, and slowly add the pre-mixed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate mixed solution C and polyvinyl alcohol in sequence during continuous stirring; continue stirring for 30 min to obtain a mixed solution F;

[0095] Step 10: slowly add the mixture D to the mixed solution F, the addition time is 4 hours, after the addition is completed, the mixed solution E is added to a four-necked flask, and after 30 minutes, the weighed ammonium sulfite is added, the temperature is controlled between 40°C and 50°C during the whole process, argon is passed, stirring is maintained (speed = 300r / min), and the reaction is continued for 4 hours to obtain the complex G;

[0096] Step 11: Take out the composite G, soak it with isopropanol and wash it 5 times, and after no isopropanol evaporates, obtain the NaX molecular sieve-based carbon-fixing concrete internal curing material.

[0097] Embodiment 2:

[0098] This example provides a method for preparing a carbon-fixing concrete internal curing material based on NaX molecular sieve, which is composed of the following raw materials by weight: 18% NaX molecular sieve, 10% carboxymethyl cellulose, 8% bagasse cellulose, 5% polyvinyl alcohol, 24% N-hydroxymethyl acrylamide, 10% maleic anhydride, 3% xanthan gum, 2% calcium silicate, 8% pentaerythritol allyl ether (PTAE), 10% acryl alcohol polyoxyethylene ether (APEG), 0.2% dimethacrylate glycerol (GDA), 0.4% triethylene glycol dimethacrylate (TEGDMA), 0.3% diallyl dimethyl ammonium chloride (DMDAAC), 0.1% ammonium sulfite, and 1% ammonia water.

[0099] The preparation method of the above-mentioned NaX molecular sieve-based carbon-fixing concrete internal curing material comprises the following steps:

[0100] Step 1: Weigh the above raw materials by mass;

[0101] Step 2: Slowly add the weighed diatomaceous earth, kaolin, sodium hydroxide and silica sol into deionized water in sequence (mass ratio is diatomaceous earth: kaolin: sodium hydroxide: silica sol: deionized water = 3:1:4:16:800) to dissolve or disperse, and ultrasonically disperse for 30 minutes to obtain suspension A;

[0102] Step 3: Slowly add the weighed NaX molecular sieve seed crystals into the suspension A, pass argon, and stir with a constant temperature magnetic stirrer at a water bath temperature of 25±2°C for 6 hours to obtain a mixed solution B with a mass concentration of 3%;

[0103] Step 4: Transfer the mixed liquid B into a sealed polymerization reactor, and gelate for 50 minutes at a microwave power of 120 W. Subsequently, increase the microwave power to 700 W and crystallize for 100 minutes. Cool the obtained product to room temperature, wash it repeatedly with distilled water until it is neutral, dry it in a vacuum oven at 60°C for 24 hours, and then grind it to obtain the NaX molecular sieve material.

[0104] Step 5: Slowly and evenly disperse the weighed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate in deionized water in turn, stir magnetically for 30 minutes, and prepare a mixed solution C with a mass concentration of 1%;

[0105] Step 6: Prepare a 13% dilute solution of maleic anhydride with deionized water, start stirring, and heat to 40° C. After complete dissolution, wait until the temperature drops to room temperature, drop weighed ammonia water, and after neutralization, add weighed N-hydroxymethyl acrylamide, pentaerythritol allyl ether (PTAE) and acryl alcohol polyoxyethylene ether (APEG) to obtain a mixture D, and transfer it into a brown bottle, protect from light, and set aside;

[0106] Step 7: Disperse the weighed glycerol dimethacrylate (GDA), triethylene glycol dimethacrylate (TEGDMA) and diallyl dimethyl ammonium chloride (DMDAAC) in deionized water in sequence, stir magnetically for 30 minutes, and prepare a mixed solution E with a concentration of 10%;

[0107] Step 8: Mechanically stir the weighed sorbitan tristearate (Span-65) and cyclohexane in a 45° C. water bath for 40 minutes to form an oil phase after the two are completely mixed;

[0108] Step 9: Slowly add the pre-obtained NaX molecular sieve to the oil phase, pass nitrogen, stir at 300 r / min for 30 min in a constant temperature water bath at 40°C, and slowly add the pre-mixed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate mixed solution C and polyvinyl alcohol in sequence during continuous stirring; continue stirring for 30 min to obtain a mixed solution F;

[0109] Step 10: slowly add the mixture D to the mixed solution F, the addition time is 4 hours, after the addition is completed, the mixed solution E is added to a four-necked flask, and after 30 minutes, the weighed ammonium sulfite is added, the temperature is controlled between 40°C and 50°C during the whole process, argon is passed, stirring is maintained (speed = 300r / min), and the reaction is continued for 4 hours to obtain the complex G;

[0110] Step 11: Take out the composite G, soak it with isopropanol and wash it 5 times, and after no isopropanol evaporates, obtain the NaX molecular sieve-based carbon-fixing concrete internal curing material.

[0111] Embodiment 3:

[0112] This example provides a method for preparing a carbon-fixing concrete internal curing material based on NaX molecular sieve, which is composed of the following raw materials by weight: 16% NaX molecular sieve, 9% carboxymethyl cellulose, 6% bagasse cellulose, 6% polyvinyl alcohol, 24% N-hydroxymethyl acrylamide, 11% maleic anhydride, 3% xanthan gum, 2% calcium silicate, 9% pentaerythritol allyl ether (PTAE), 11% acryl alcohol polyoxyethylene ether (APEG), 0.17% dimethacrylate glycerol (GDA), 0.23% triethylene glycol dimethacrylate (TEGDMA), 0.4% diallyl dimethyl ammonium chloride (DMDAAC), 0.2% ammonium sulfite, and 1% ammonia water.

[0113] The preparation method of the above-mentioned NaX molecular sieve-based carbon-fixing concrete internal curing material comprises the following steps:

[0114] Step 1: Weigh the above raw materials by mass;

[0115] Step 2: Slowly add the weighed diatomaceous earth, kaolin, sodium hydroxide and silica sol into deionized water in sequence (mass ratio is diatomaceous earth: kaolin: sodium hydroxide: silica sol: deionized water = 3:1:4:16:800) to dissolve or disperse, and ultrasonically disperse for 30 minutes to obtain suspension A;

[0116] Step 3: Slowly add the weighed NaX molecular sieve seed crystals into the suspension A, pass argon, and stir with a constant temperature magnetic stirrer at a water bath temperature of 25±2°C for 6 hours to obtain a mixed solution B with a mass concentration of 3%;

[0117] Step 4: Transfer the mixed solution B to a sealed polymerization reactor, and perform gelation for 50 min at a microwave power of 120 W. Subsequently, increase the microwave power to 700 W and perform crystallization for 100 min. Cool the obtained product to room temperature, wash it repeatedly with distilled water until it is neutral, dry it in a vacuum oven at 60° C. for 24 h, and then grind it to obtain a NaX molecular sieve material.

[0118] Step 5: Slowly and evenly disperse the weighed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate in deionized water in turn, stir magnetically for 30 minutes, and prepare a mixed solution C with a mass concentration of 1%;

[0119] Step 6: Prepare a 13% dilute solution of maleic anhydride with deionized water, start stirring, and heat to 40° C. After complete dissolution, wait until the temperature drops to room temperature, drop weighed ammonia water, and after neutralization, add weighed N-hydroxymethyl acrylamide, pentaerythritol allyl ether (PTAE) and acryl alcohol polyoxyethylene ether (APEG) to obtain a mixture D, and transfer it into a brown bottle, protect from light, and set aside;

[0120] Step 7: Disperse the weighed glycerol dimethacrylate (GDA), triethylene glycol dimethacrylate (TEGDMA) and diallyl dimethyl ammonium chloride (DMDAAC) in deionized water in sequence, stir magnetically for 30 minutes, and prepare a mixed solution E with a concentration of 10%;

[0121] Step 8: Mechanically stir the weighed sorbitan tristearate (Span-65) and cyclohexane in a 45° C. water bath for 40 minutes to form an oil phase after the two are completely mixed;

[0122] Step 9: Slowly add the pre-obtained NaX molecular sieve to the oil phase, pass nitrogen, stir at 300 r / min for 30 min in a constant temperature water bath at 40°C, and slowly add the pre-mixed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate mixed solution C and polyvinyl alcohol in sequence during continuous stirring; continue stirring for 30 min to obtain a mixed solution F;

[0123] Step 10: slowly add the mixture D to the mixed solution F, the addition time is 4 hours, after the addition is completed, the mixed solution E is added to a four-necked flask, and after 30 minutes, the weighed ammonium sulfite is added, the temperature is controlled between 40°C and 50°C during the whole process, argon is passed, stirring is maintained (speed = 300r / min), and the reaction is continued for 4 hours to obtain the complex G;

[0124] Step 11: Take out the composite G, soak it with isopropanol and wash it 5 times, and after no isopropanol evaporates, obtain the NaX molecular sieve-based carbon-fixing concrete internal curing material.

[0125] Embodiment 4:

[0126] This example provides a method for preparing a carbon-fixing concrete internal curing material based on NaX molecular sieve, which is composed of the following raw materials by weight: 15% NaX molecular sieve, 8% carboxymethyl cellulose, 6% bagasse cellulose, 5% polyvinyl alcohol, 26% N-hydroxymethyl acrylamide, 10% maleic anhydride, 4% xanthan gum, 2% calcium silicate, 8% pentaerythritol allyl ether (PTAE), 12% acryl alcohol polyoxyethylene ether (APEG), 0.18% dimethacrylate glycerol (GDA), 0.3% triethylene glycol dimethacrylate (TEGDMA), 0.32% diallyl dimethyl ammonium chloride (DMDAAC), 0.2% ammonium sulfite, and 3% ammonia water.

[0127] The preparation method of the above-mentioned NaX molecular sieve-based carbon-fixing concrete internal curing material comprises the following steps:

[0128] Step 1: Weigh the above raw materials by mass;

[0129] Step 2: Slowly add the weighed diatomaceous earth, kaolin, sodium hydroxide and silica sol into deionized water in sequence (mass ratio is diatomaceous earth: kaolin: sodium hydroxide: silica sol: deionized water = 3:1:4:16:800) to dissolve or disperse, and ultrasonically disperse for 30 minutes to obtain suspension A;

[0130] Step 3: Slowly add the weighed NaX molecular sieve seed crystals into the suspension A, pass argon, and stir with a constant temperature magnetic stirrer at a water bath temperature of 25±2°C for 6 hours to obtain a mixed solution B with a mass concentration of 3%;

[0131] Step 4: Transfer the mixed solution B to a sealed polymerization reactor, and perform gelation for 50 min at a microwave power of 120 W. Subsequently, increase the microwave power to 700 W and perform crystallization for 100 min. Cool the obtained product to room temperature, wash it repeatedly with distilled water until it is neutral, dry it in a vacuum oven at 60° C. for 24 h, and then grind it to obtain a NaX molecular sieve material.

[0132] Step 5: Slowly and evenly disperse the weighed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate in deionized water in turn, stir magnetically for 30 minutes, and prepare a mixed solution C with a mass concentration of 1%;

[0133] Step 6: Prepare a 13% dilute solution of maleic anhydride with deionized water, start stirring, and heat to 40° C. After complete dissolution, wait until the temperature drops to room temperature, drop weighed ammonia water, and after neutralization, add weighed N-hydroxymethyl acrylamide, pentaerythritol allyl ether (PTAE) and acryl alcohol polyoxyethylene ether (APEG) to obtain a mixture D, and transfer it into a brown bottle, protect from light, and set aside;

[0134] Step 7: Disperse the weighed glycerol dimethacrylate (GDA), triethylene glycol dimethacrylate (TEGDMA) and diallyl dimethyl ammonium chloride (DMDAAC) in deionized water in sequence, stir magnetically for 30 minutes, and prepare a mixed solution E with a concentration of 10%;

[0135] Step 8: Mechanically stir the weighed sorbitan tristearate (Span-65) and cyclohexane in a 45° C. water bath for 40 minutes to form an oil phase after the two are completely mixed;

[0136] Step 9: Slowly add the pre-obtained NaX molecular sieve to the oil phase, pass nitrogen, stir at 300 r / min for 30 min in a constant temperature water bath at 40°C, and slowly add the pre-mixed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate mixed solution C and polyvinyl alcohol in sequence during continuous stirring; continue stirring for 30 min to obtain a mixed solution F;

[0137] Step 10: slowly add the mixture D to the mixed solution F, the addition time is 4 hours, after the addition is completed, the mixed solution E is added to a four-necked flask, and after 30 minutes, the weighed ammonium sulfite is added, the temperature is controlled between 40°C and 50°C during the whole process, argon is passed, stirring is maintained (speed = 300r / min), and the reaction is continued for 4 hours to obtain the complex G;

[0138] Step 11: Take out the composite G, soak it with isopropanol and wash it 5 times, and after no isopropanol evaporates, obtain the NaX molecular sieve-based carbon-fixing concrete internal curing material.

[0139] Embodiment 5:

[0140] This example provides a method for preparing a carbon-fixing concrete internal curing material based on NaX molecular sieve, which is composed of the following raw materials by weight: 15% NaX molecular sieve, 9% carboxymethyl cellulose, 7% bagasse cellulose, 7% polyvinyl alcohol, 24% N-hydroxymethyl acrylamide, 12% maleic anhydride, 3.3% xanthan gum, 2.5% calcium silicate, 8% pentaerythritol allyl ether (PTAE), 10% acryl alcohol polyoxyethylene ether (APEG), 0.15% dimethacrylate glycerol (GDA), 0.27% triethylene glycol dimethacrylate (TEGDMA), 0.7% diallyl dimethyl ammonium chloride (DMDAAC), 0.08% ammonium sulfite, and 1% ammonia water.

[0141] The preparation method of the above-mentioned NaX molecular sieve-based carbon-fixing concrete internal curing material comprises the following steps:

[0142] Step 1: Weigh the above raw materials by mass;

[0143] Step 2: Slowly add the weighed diatomaceous earth, kaolin, sodium hydroxide and silica sol into deionized water in sequence (mass ratio is diatomaceous earth: kaolin: sodium hydroxide: silica sol: deionized water = 3:1:4:16:800) to dissolve or disperse, and ultrasonically disperse for 30 minutes to obtain suspension A;

[0144] Step 3: Slowly add the weighed NaX molecular sieve seed crystals into the suspension A, pass argon, and stir with a constant temperature magnetic stirrer at a water bath temperature of 25±2°C for 6 hours to obtain a mixed solution B with a mass concentration of 3%;

[0145] Step 4: Transfer the mixed solution B to a sealed polymerization reactor, and perform gelation for 50 min at a microwave power of 120 W. Subsequently, increase the microwave power to 700 W and perform crystallization for 100 min. Cool the obtained product to room temperature, wash it repeatedly with distilled water until it is neutral, dry it in a vacuum oven at 60° C. for 24 h, and then grind it to obtain a NaX molecular sieve material.

[0146] Step 5: Slowly and evenly disperse the weighed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate in deionized water in turn, stir magnetically for 30 minutes, and prepare a mixed solution C with a mass concentration of 1%;

[0147] Step 6: Prepare a 13% dilute solution of maleic anhydride with deionized water, start stirring, and heat to 40° C. After complete dissolution, wait until the temperature drops to room temperature, drop weighed ammonia water, and after neutralization, add weighed N-hydroxymethyl acrylamide, pentaerythritol allyl ether (PTAE) and acryl alcohol polyoxyethylene ether (APEG) to obtain a mixture D, and transfer it into a brown bottle, protect from light, and set aside;

[0148] Step 7: Disperse the weighed glycerol dimethacrylate (GDA), triethylene glycol dimethacrylate (TEGDMA) and diallyl dimethyl ammonium chloride (DMDAAC) in deionized water in sequence, stir magnetically for 30 minutes, and prepare a mixed solution E with a concentration of 10%;

[0149] Step 8: Mechanically stir the weighed sorbitan tristearate (Span-65) and cyclohexane in a 45° C. water bath for 40 minutes to form an oil phase after the two are completely mixed;

[0150] Step 9: Slowly add the pre-obtained NaX molecular sieve to the oil phase, pass nitrogen, stir at 300 r / min for 30 min in a constant temperature water bath at 40°C, and slowly add the pre-mixed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate mixed solution C and polyvinyl alcohol in sequence during continuous stirring; continue stirring for 30 min to obtain a mixed solution F;

[0151] Step 10: slowly add the mixture D to the mixed solution F, the addition time is 4 hours, after the addition is completed, the mixed solution E is added to a four-necked flask, and after 30 minutes, the weighed ammonium sulfite is added, the temperature is controlled between 40°C and 50°C during the whole process, argon is passed, stirring is maintained (speed = 300r / min), and the reaction is continued for 4 hours to obtain the complex G;

[0152] Step 11: Take out the composite G, soak it with isopropanol and wash it 5 times, and after no isopropanol evaporates, obtain the NaX molecular sieve-based carbon-fixing concrete internal curing material.

[0153] Embodiment 6:

[0154] This example provides a method for preparing a carbon-fixing concrete internal curing material based on NaX molecular sieve, which is composed of the following raw materials by weight: 16% NaX molecular sieve, 8% carboxymethyl cellulose, 6% bagasse cellulose, 5% polyvinyl alcohol, 27% N-hydroxymethyl acrylamide, 10% maleic anhydride, 3% xanthan gum, 2% calcium silicate, 8% pentaerythritol allyl ether (PTAE), 13% acryl alcohol polyoxyethylene ether (APEG), 0.15% dimethacrylate glycerol (GDA), 0.27% triethylene glycol dimethacrylate (TEGDMA), 0.5% diallyl dimethyl ammonium chloride (DMDAAC), 0.08% ammonium sulfite, and 1% ammonia water.

[0155] The preparation method of the above-mentioned NaX molecular sieve-based carbon-fixing concrete internal curing material comprises the following steps:

[0156] Step 1: Weigh the above raw materials by mass;

[0157] Step 2: Slowly add the weighed diatomaceous earth, kaolin, sodium hydroxide and silica sol into deionized water in sequence (mass ratio is diatomaceous earth: kaolin: sodium hydroxide: silica sol: deionized water = 3:1:4:16:800) to dissolve or disperse, and ultrasonically disperse for 30 minutes to obtain suspension A;

[0158] Step 3: Slowly add the weighed NaX molecular sieve seed crystals into the suspension A, pass argon, and stir with a constant temperature magnetic stirrer at a water bath temperature of 25±2°C for 6 hours to obtain a mixed solution B with a mass concentration of 3%;

[0159] Step 4: Transfer the mixed solution B to a sealed polymerization reactor, and perform gelation for 50 min at a microwave power of 120 W. Subsequently, increase the microwave power to 700 W and perform crystallization for 100 min. Cool the obtained product to room temperature, wash it repeatedly with distilled water until it is neutral, dry it in a vacuum oven at 60° C. for 24 h, and then grind it to obtain a NaX molecular sieve material.

[0160] Step 5: Slowly and evenly disperse the weighed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate in deionized water in turn, stir magnetically for 30 minutes, and prepare a mixed solution C with a mass concentration of 1%;

[0161] Step 6: Prepare a 13% dilute solution of maleic anhydride with deionized water, start stirring, and heat to 40° C. After complete dissolution, wait until the temperature drops to room temperature, drop weighed ammonia water, and after neutralization, add weighed N-hydroxymethyl acrylamide, pentaerythritol allyl ether (PTAE) and acryl alcohol polyoxyethylene ether (APEG) to obtain a mixture D, and transfer it into a brown bottle, protect from light, and set aside;

[0162] Step 7: Disperse the weighed glycerol dimethacrylate (GDA), triethylene glycol dimethacrylate (TEGDMA) and diallyl dimethyl ammonium chloride (DMDAAC) in deionized water in sequence, stir magnetically for 30 minutes, and prepare a mixed solution E with a concentration of 10%;

[0163] Step 8: Mechanically stir the weighed sorbitan tristearate (Span-65) and cyclohexane in a 45° C. water bath for 40 minutes to form an oil phase after the two are completely mixed;

[0164] Step 9: Slowly add the pre-obtained NaX molecular sieve to the oil phase, pass nitrogen, stir at 300 r / min for 30 min in a constant temperature water bath at 40°C, and slowly add the pre-mixed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate mixed solution C and polyvinyl alcohol in sequence during continuous stirring; continue stirring for 30 min to obtain a mixed solution F;

[0165] Step 10: slowly add the mixture D to the mixed solution F, the addition time is 4 hours, after the addition is completed, the mixed solution E is added to a four-necked flask, and after 30 minutes, the weighed ammonium sulfite is added, the temperature is controlled between 40°C and 50°C during the whole process, argon is passed, stirring is maintained (speed = 300r / min), and the reaction is continued for 4 hours to obtain the complex G;

[0166] Step 11: Take out the composite G, soak it with isopropanol and wash it 5 times, and after no isopropanol evaporates, obtain the NaX molecular sieve-based carbon-fixing concrete internal curing material.

[0167] Embodiment 7:

[0168] This example provides a method for preparing a carbon-fixing concrete internal curing material based on NaX molecular sieve, which is composed of the following raw materials by weight: 15% NaX molecular sieve, 8% carboxymethyl cellulose, 6% bagasse cellulose, 10% polyvinyl alcohol, 24% N-hydroxymethyl acrylamide, 10% maleic anhydride, 3% xanthan gum, 2% calcium silicate, 8% pentaerythritol allyl ether (PTAE), 11% acryl alcohol polyoxyethylene ether (APEG), 0.2% dimethacrylate glycerol (GDA), 0.4% triethylene glycol dimethacrylate (TEGDMA), 0.5% diallyl dimethyl ammonium chloride (DMDAAC), 0.5% ammonium sulfite, and 1.4% ammonia water.

[0169] The preparation method of the above-mentioned NaX molecular sieve-based carbon-fixing concrete internal curing material comprises the following steps:

[0170] Step 1: Weigh the above raw materials by mass;

[0171] Step 2: Slowly add the weighed diatomaceous earth, kaolin, sodium hydroxide and silica sol into deionized water in sequence (mass ratio is diatomaceous earth: kaolin: sodium hydroxide: silica sol: deionized water = 3:1:4:16:800) to dissolve or disperse, and ultrasonically disperse for 30 minutes to obtain suspension A;

[0172] Step 3: Slowly add the weighed NaX molecular sieve seed crystals into the suspension A, pass argon, and stir with a constant temperature magnetic stirrer at a water bath temperature of 25±2°C for 6 hours to obtain a mixed solution B with a mass concentration of 3%;

[0173] Step 4: Transfer the mixed solution B to a sealed polymerization reactor, and perform gelation for 50 min at a microwave power of 120 W. Subsequently, increase the microwave power to 700 W and perform crystallization for 100 min. Cool the obtained product to room temperature, wash it repeatedly with distilled water until it is neutral, dry it in a vacuum oven at 60° C. for 24 h, and then grind it to obtain a NaX molecular sieve material.

[0174] Step 5: Slowly and evenly disperse the weighed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate in deionized water in turn, stir magnetically for 30 minutes, and prepare a mixed solution C with a mass concentration of 1%;

[0175] Step 6: Prepare a 13% dilute solution of maleic anhydride with deionized water, start stirring, and heat to 40° C. After complete dissolution, wait until the temperature drops to room temperature, drop weighed ammonia water, and after neutralization, add weighed N-hydroxymethyl acrylamide, pentaerythritol allyl ether (PTAE) and acryl alcohol polyoxyethylene ether (APEG) to obtain a mixture D, and transfer it into a brown bottle, protect from light, and set aside;

[0176] Step 7: Disperse the weighed glycerol dimethacrylate (GDA), triethylene glycol dimethacrylate (TEGDMA) and diallyl dimethyl ammonium chloride (DMDAAC) in deionized water in sequence, stir magnetically for 30 minutes, and prepare a mixed solution E with a concentration of 10%;

[0177] Step 8: Mechanically stir the weighed sorbitan tristearate (Span-65) and cyclohexane in a 45° C. water bath for 40 minutes to form an oil phase after the two are completely mixed;

[0178] Step 9: Slowly add the pre-obtained NaX molecular sieve to the oil phase, pass nitrogen, stir at 300 r / min for 30 min in a constant temperature water bath at 40°C, and slowly add the pre-mixed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate mixed solution C and polyvinyl alcohol in sequence during continuous stirring; continue stirring for 30 min to obtain a mixed solution F;

[0179] Step 10: slowly add the mixture D to the mixed solution F, the addition time is 4 hours, after the addition is completed, the mixed solution E is added to a four-necked flask, and after 30 minutes, the weighed ammonium sulfite is added, the temperature is controlled between 40°C and 50°C during the whole process, argon is passed, stirring is maintained (speed = 300r / min), and the reaction is continued for 4 hours to obtain the complex G;

[0180] Step 11: Take out the composite G, soak it with isopropanol and wash it 5 times, and after no isopropanol evaporates, obtain the NaX molecular sieve-based carbon-fixing concrete internal curing material.

[0181] Embodiment 8:

[0182] This example provides a method for preparing a carbon-fixing concrete internal curing material based on NaX molecular sieve, which is composed of the following raw materials by weight: 15% NaX molecular sieve, 8% carboxymethyl cellulose, 6% bagasse cellulose, 5% polyvinyl alcohol, 24% N-hydroxymethyl acrylamide, 15% maleic anhydride, 3% xanthan gum, 2% calcium silicate, 10% pentaerythritol allyl ether (PTAE), 10% acryl alcohol polyoxyethylene ether (APEG), 0.15% dimethacrylate glycerol (GDA), 0.2% triethylene glycol dimethacrylate (TEGDMA), 0.3% diallyl dimethyl ammonium chloride (DMDAAC), 0.08% ammonium sulfite, and 1.27% ammonia water.

[0183] The preparation method of the above-mentioned NaX molecular sieve-based carbon-fixing concrete internal curing material comprises the following steps:

[0184] Step 1: Weigh the above raw materials by mass;

[0185] Step 2: Slowly add the weighed diatomaceous earth, kaolin, sodium hydroxide and silica sol into deionized water in sequence (mass ratio is diatomaceous earth: kaolin: sodium hydroxide: silica sol: deionized water = 3:1:4:16:800) to dissolve or disperse, and ultrasonically disperse for 30 minutes to obtain suspension A;

[0186] Step 3: Slowly add the weighed NaX molecular sieve seed crystals into the suspension A, pass argon, and stir with a constant temperature magnetic stirrer at a water bath temperature of 25±2°C for 6 hours to obtain a mixed solution B with a mass concentration of 3%;

[0187] Step 4: Transfer the mixed solution B to a sealed polymerization reactor, and perform gelation for 50 min at a microwave power of 120 W. Subsequently, increase the microwave power to 700 W and perform crystallization for 100 min. Cool the obtained product to room temperature, wash it repeatedly with distilled water until it is neutral, dry it in a vacuum oven at 60° C. for 24 h, and then grind it to obtain a NaX molecular sieve material.

[0188] Step 5: Slowly and evenly disperse the weighed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate in deionized water in turn, stir magnetically for 30 minutes, and prepare a mixed solution C with a mass concentration of 1%;

[0189] Step 6: Prepare a 13% dilute solution of maleic anhydride with deionized water, start stirring, and heat to 40° C. After complete dissolution, wait until the temperature drops to room temperature, drop weighed ammonia water, and after neutralization, add weighed N-hydroxymethyl acrylamide, pentaerythritol allyl ether (PTAE) and acryl alcohol polyoxyethylene ether (APEG) to obtain a mixture D, and transfer it into a brown bottle, protect from light, and set aside;

[0190] Step 7: Disperse the weighed glycerol dimethacrylate (GDA), triethylene glycol dimethacrylate (TEGDMA) and diallyl dimethyl ammonium chloride (DMDAAC) in deionized water in sequence, stir magnetically for 30 minutes, and prepare a mixed solution E with a concentration of 10%;

[0191] Step 8: Mechanically stir the weighed sorbitan tristearate (Span-65) and cyclohexane in a 45° C. water bath for 40 minutes to form an oil phase after the two are completely mixed;

[0192] Step 9: Slowly add the pre-obtained NaX molecular sieve to the oil phase, pass nitrogen, stir at 300 r / min for 30 min in a constant temperature water bath at 40°C, and slowly add the pre-mixed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate mixed solution C and polyvinyl alcohol in sequence during continuous stirring; continue stirring for 30 min to obtain a mixed solution F;

[0193] Step 10: slowly add the mixture D to the mixed solution F, the addition time is 4 hours, after the addition is completed, the mixed solution E is added to a four-necked flask, and after 30 minutes, the weighed ammonium sulfite is added, the temperature is controlled between 40°C and 50°C during the whole process, argon is passed, stirring is maintained (speed = 300r / min), and the reaction is continued for 4 hours to obtain the complex G;

[0194] Step 11: Take out the composite G, soak it with isopropanol and wash it 5 times, and after no isopropanol evaporates, obtain the NaX molecular sieve-based carbon-fixing concrete internal curing material.

[0195] Comparative Example 1:

[0196] This comparative example provides a method for preparing a carbon-fixing concrete internal curing material based on NaX molecular sieve, which is composed of the following raw materials by weight: 16% NaX molecular sieve, 10% polyvinyl alcohol, 30% N-hydroxymethyl acrylamide, 15% maleic anhydride, 3% xanthan gum, 2% calcium silicate, 9% pentaerythritol allyl ether (PTAE), 11% acryl alcohol polyoxyethylene ether (APEG), 0.17% dimethacrylate glycerol (GDA), 0.23% triethylene glycol dimethacrylate (TEGDMA), 0.4% diallyl dimethyl ammonium chloride (DMDAAC), 0.2% ammonium sulfite, and 3% ammonia water.

[0197] The preparation method of the above-mentioned NaX molecular sieve-based carbon-fixing concrete internal curing material comprises the following steps:

[0198] Step 1: Weigh the above raw materials by mass;

[0199] Step 2: Slowly add the weighed diatomaceous earth, kaolin, sodium hydroxide and silica sol into deionized water in sequence (mass ratio is diatomaceous earth: kaolin: sodium hydroxide: silica sol: deionized water = 3:1:4:16:800) to dissolve or disperse, and ultrasonically disperse for 30 minutes to obtain suspension A;

[0200] Step 3: Slowly add the weighed NaX molecular sieve seed crystals into the suspension A, pass argon, and stir with a constant temperature magnetic stirrer at a water bath temperature of 25±2°C for 6 hours to obtain a mixed solution B with a mass concentration of 3%;

[0201] Step 4: Transfer the mixed solution B to a sealed polymerization reactor, and perform gelation for 50 min at a microwave power of 120 W. Subsequently, increase the microwave power to 700 W and perform crystallization for 100 min. Cool the obtained product to room temperature, wash it repeatedly with distilled water until it is neutral, dry it in a vacuum oven at 60° C. for 24 h, and then grind it to obtain a NaX molecular sieve material.

[0202] Step 5: Slowly and evenly disperse the weighed xanthan gum and calcium silicate in deionized water in turn, stir magnetically for 30 minutes, and prepare a mixed solution C with a mass concentration of 1%;

[0203] Step 6: Prepare a 13% dilute solution of maleic anhydride with deionized water, start stirring, and heat to 40° C. After complete dissolution, wait until the temperature drops to room temperature, drop weighed ammonia water, and after neutralization, add weighed N-hydroxymethyl acrylamide, pentaerythritol allyl ether (PTAE) and acryl alcohol polyoxyethylene ether (APEG) to obtain a mixture D, and transfer it into a brown bottle, protect from light, and set aside;

[0204] Step 7: Disperse the weighed glycerol dimethacrylate (GDA), triethylene glycol dimethacrylate (TEGDMA) and diallyl dimethyl ammonium chloride (DMDAAC) in deionized water in sequence, stir magnetically for 30 minutes, and prepare a mixed solution E with a concentration of 10%;

[0205] Step 8: Mechanically stir the weighed sorbitan tristearate (Span-65) and cyclohexane in a 45° C. water bath for 40 minutes to form an oil phase after the two are completely mixed;

[0206] Step 9: Slowly add the pre-obtained NaX molecular sieve to the oil phase, pass nitrogen, stir at 300 r / min for 30 min in a 40°C constant temperature water bath environment, and slowly add the pre-mixed xanthan gum and calcium silicate mixed solution C and polyvinyl alcohol in sequence during the continuous stirring process; continue stirring for 30 min to obtain a mixed solution F;

[0207] Step 10: slowly add the mixture D to the mixed solution F, the addition time is 4 hours, after the addition is completed, the mixed solution E is added to a four-necked flask, and after 30 minutes, the weighed ammonium sulfite is added, the temperature is controlled between 40°C and 50°C during the whole process, argon is passed, stirring is maintained (speed = 300r / min), and the reaction is continued for 4 hours to obtain the complex G;

[0208] Step 11: Take out the composite G, soak it with isopropanol and wash it 5 times, and after no isopropanol evaporates, obtain the NaX molecular sieve-based carbon-fixing concrete internal curing material.

[0209] Comparative Example 2:

[0210] This comparative example provides a method for preparing a carbon-fixing concrete internal curing material based on NaX molecular sieve, which is composed of the following raw materials by weight: 18% NaX molecular sieve, 10% carboxymethyl cellulose, 8% bagasse cellulose, 10% polyvinyl alcohol, 20% maleic anhydride, 4% xanthan gum, 3% calcium silicate, 10% pentaerythritol allyl ether (PTAE), 13% acryl alcohol polyoxyethylene ether (APEG), 0.15% dimethacrylate glycerol (GDA), 0.27% triethylene glycol dimethacrylate (TEGDMA), 0.5% diallyl dimethyl ammonium chloride (DMDAAC), 0.08% ammonium sulfite, and 3% ammonia water.

[0211] The preparation method of the above-mentioned NaX molecular sieve-based carbon-fixing concrete internal curing material comprises the following steps:

[0212] Step 1: Weigh the above raw materials by mass;

[0213] Step 2: Slowly add the weighed diatomaceous earth, kaolin, sodium hydroxide and silica sol into deionized water in sequence (mass ratio is diatomaceous earth: kaolin: sodium hydroxide: silica sol: deionized water = 3:1:4:16:800) to dissolve or disperse, and ultrasonically disperse for 30 minutes to obtain suspension A;

[0214] Step 3: Slowly add the weighed NaX molecular sieve seed crystals into the suspension A, pass argon, and stir with a constant temperature magnetic stirrer at a water bath temperature of 25±2°C for 6 hours to obtain a mixed solution B with a mass concentration of 3%;

[0215] Step 4: Transfer the mixed solution B to a sealed polymerization reactor, and perform gelation for 50 min at a microwave power of 120 W. Subsequently, increase the microwave power to 700 W and perform crystallization for 100 min. Cool the obtained product to room temperature, wash it repeatedly with distilled water until it is neutral, dry it in a vacuum oven at 60° C. for 24 h, and then grind it to obtain a NaX molecular sieve material.

[0216] Step 5: The weighed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate are slowly and evenly dispersed in deionized water in sequence, and magnetically stirred for 30 minutes to prepare a mixed solution C with a mass concentration of 1%;

[0217] Step 6: Use deionized water to prepare a 13% dilute solution of maleic anhydride, start stirring, and heat to 40°C; after complete dissolution, wait until the temperature drops to room temperature, drop weighed ammonia water, and after neutralization, add weighed pentaerythritol allyl ether (PTAE) and acryl alcohol polyoxyethylene ether (APEG) to obtain a mixture D, and transfer it into a brown bottle, protect it from light, and set aside;

[0218] Step 7: Disperse the weighed glycerol dimethacrylate (GDA), triethylene glycol dimethacrylate (TEGDMA) and diallyl dimethyl ammonium chloride (DMDAAC) in deionized water in sequence, stir magnetically for 30 minutes, and prepare a mixed solution E with a concentration of 10%;

[0219] Step 8: Mechanically stir the weighed sorbitan tristearate (Span-65) and cyclohexane in a 45° C. water bath for 40 minutes to form an oil phase after the two are completely mixed;

[0220] Step 9: Slowly add the pre-obtained NaX molecular sieve to the oil phase, pass nitrogen, stir at 300 r / min for 30 min in a 40°C constant temperature water bath environment, and slowly add the pre-selected mixed solution C of carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate and polyvinyl alcohol in sequence during the continuous stirring process; continue stirring for 30 min to obtain a mixed solution F;

[0221] Step 10: slowly add the mixture D to the mixed solution F, the addition time is 4 hours, after the addition is completed, the mixed solution E is added to a four-necked flask, and after 30 minutes, the weighed ammonium sulfite is added, the temperature is controlled between 40°C and 50°C during the whole process, argon is passed, stirring is maintained (speed = 300r / min), and the reaction is continued for 4 hours to obtain the complex G;

[0222] Step 11: Take out the composite G, soak it with isopropanol and wash it 5 times, and after no isopropanol evaporates, obtain the NaX molecular sieve-based carbon-fixing concrete internal curing material.

[0223] Comparative Example 3:

[0224] This comparative example provides a method for preparing a carbon-fixing concrete internal curing material based on NaX molecular sieve, which is composed of the following raw materials by weight: 18% NaX molecular sieve, 8% carboxymethyl cellulose, 6% bagasse cellulose, 5% polyvinyl alcohol, 24% N-hydroxymethyl acrylamide, 15% maleic anhydride, 3% xanthan gum, 8% pentaerythritol allyl ether (PTAE), 10% acryl alcohol polyoxyethylene ether (APEG), 0.15% dimethacrylate glycerol (GDA), 0.2% triethylene glycol dimethacrylate (TEGDMA), 0.3% diallyl dimethyl ammonium chloride (DMDAAC), 0.08% ammonium sulfite, and 2.27% ammonia water.

[0225] The preparation method of the above-mentioned NaX molecular sieve-based carbon-fixing concrete internal curing material comprises the following steps:

[0226] Step 1: Weigh the above raw materials by mass;

[0227] Step 2: Slowly add the weighed diatomaceous earth, kaolin, sodium hydroxide and silica sol into deionized water in sequence (mass ratio is diatomaceous earth: kaolin: sodium hydroxide: silica sol: deionized water = 3:1:4:16:800) to dissolve or disperse, and ultrasonically disperse for 30 minutes to obtain suspension A;

[0228] Step 3: Slowly add the weighed NaX molecular sieve seed crystals into the suspension A, pass argon, and stir with a constant temperature magnetic stirrer at a water bath temperature of 25±2°C for 6 hours to obtain a mixed solution B with a mass concentration of 3%;

[0229] Step 4: Transfer the mixed solution B to a sealed polymerization reactor, and perform gelation for 50 min at a microwave power of 120 W. Subsequently, increase the microwave power to 700 W and perform crystallization for 100 min. Cool the obtained product to room temperature, wash it repeatedly with distilled water until it is neutral, dry it in a vacuum oven at 60° C. for 24 h, and then grind it to obtain a NaX molecular sieve material.

[0230] Step 5: The weighed carboxymethyl cellulose, bagasse cellulose and xanthan gum are slowly and evenly dispersed in deionized water in sequence, and magnetically stirred for 30 minutes to prepare a mixed solution C with a mass concentration of 1%;

[0231] Step 6: Prepare a 13% dilute solution of maleic anhydride with deionized water, start stirring, and heat to 40° C. After complete dissolution, wait until the temperature drops to room temperature, drop weighed ammonia water, and after neutralization, add weighed N-hydroxymethyl acrylamide, pentaerythritol allyl ether (PTAE) and acryl alcohol polyoxyethylene ether (APEG) to obtain a mixture D, and transfer it into a brown bottle, protect from light, and set aside;

[0232] Step 7: Disperse the weighed glycerol dimethacrylate (GDA), triethylene glycol dimethacrylate (TEGDMA) and diallyl dimethyl ammonium chloride (DMDAAC) in deionized water in sequence, stir magnetically for 30 minutes, and prepare a mixed solution E with a concentration of 10%;

[0233] Step 8: Mechanically stir the weighed sorbitan tristearate (Span-65) and cyclohexane in a 45° C. water bath for 40 minutes to form an oil phase after the two are completely mixed;

[0234] Step 9: Slowly add the pre-obtained NaX molecular sieve to the oil phase, pass nitrogen, stir at 300 r / min for 30 min in a 40°C constant temperature water bath environment, and slowly add the pre-selected mixed solution C of carboxymethyl cellulose, bagasse cellulose and xanthan gum and polyvinyl alcohol in sequence during the continuous stirring process; continue stirring for 30 min to obtain a mixed solution F;

[0235] Step 10: slowly add the mixture D to the mixed solution F, the addition time is 4 hours, after the addition is completed, the mixed solution E is added to a four-necked flask, and after 30 minutes, the weighed ammonium sulfite is added, the temperature is controlled between 40°C and 50°C during the whole process, argon is passed, stirring is maintained (speed = 300r / min), and the reaction is continued for 4 hours to obtain the complex G;

[0236] Step 11: Take out the composite G, soak it with isopropanol and wash it 5 times, and after no isopropanol evaporates, obtain the NaX molecular sieve-based carbon-fixing concrete internal curing material.

[0237] Comparative Example 4:

[0238] The present comparative example provides a method for preparing a carbon-fixing concrete internal curing material based on NaX molecular sieve, which is composed of the following raw materials by weight: 10% carboxymethyl cellulose, 8% bagasse cellulose, 10% polyvinyl alcohol, 30% N-hydroxymethyl acrylamide, 10% maleic anhydride, 4% xanthan gum, 3% calcium silicate, 10% pentaerythritol allyl ether (PTAE), 13% acryl alcohol polyoxyethylene ether (APEG), 0.2% glycerol dimethacrylate (GDA), 0.4% triethylene glycol dimethacrylate (TEGDMA), 0.3% diallyl dimethyl ammonium chloride (DMDAAC), 0.1% ammonium sulfite, and 1% ammonia water.

[0239] The preparation method of the above-mentioned NaX molecular sieve-based carbon-fixing concrete internal curing material comprises the following steps:

[0240] Step 1: Slowly and evenly disperse the weighed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate in deionized water in turn, stir magnetically for 30 minutes, and prepare a mixed solution A with a mass concentration of 1%;

[0241] Step 2: Use deionized water to prepare a 13% dilute solution of maleic anhydride, start stirring, and heat to 40°C; after complete dissolution, wait until the temperature drops to room temperature, drop weighed ammonia water, and after neutralization, add weighed N-hydroxymethyl acrylamide, pentaerythritol allyl ether (PTAE) and acryl alcohol polyoxyethylene ether (APEG) to obtain a mixture B, and transfer it into a brown bottle, protect it from light, and set aside;

[0242] Step 3: Disperse the weighed glycerol dimethacrylate (GDA), triethylene glycol dimethacrylate (TEGDMA) and diallyl dimethyl ammonium chloride (DMDAAC) in deionized water in sequence, stir magnetically for 30 minutes, and prepare a mixed solution C with a concentration of 10%;

[0243] Step 4: Mechanically stir the weighed sorbitan tristearate (Span-65) and cyclohexane in a 45°C water bath for 40 minutes to form an oil phase after the two are completely mixed;

[0244] Step 5: In a nitrogen atmosphere, the mixture was stirred at 300 r / min for 30 min in a constant temperature water bath at 40°C. During the continuous stirring process, the pre-mixed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate solution A and polyvinyl alcohol were slowly added in sequence; the mixture was stirred for 30 min to obtain a mixed solution D;

[0245] Step 5: slowly add the mixture B to the mixed solution D, the addition time is 4 hours, after the addition is completed, the mixed solution C is added to a four-necked flask, and after 30 minutes, the weighed ammonium sulfite is added, the temperature is controlled between 40°C and 50°C during the whole process, argon is passed, stirring is maintained (speed = 300r / min), and the reaction is continued for 4 hours to obtain the complex E;

[0246] Step 6: Take out the composite E, soak and wash it with isopropanol for 5 times, and after no isopropanol evaporates, obtain the NaX molecular sieve-based carbon-fixing concrete internal curing material.

[0247] Comparative Example 5:

[0248] This comparative example provides a method for preparing a carbon-fixing concrete internal curing material based on NaX molecular sieve, which is composed of the following raw materials by weight: 17% NaX molecular sieve, 10% carboxymethyl cellulose, 8% bagasse cellulose, 10% polyvinyl alcohol, 30% N-hydroxymethyl acrylamide, 3.3% xanthan gum, 2.5% calcium silicate, 8% pentaerythritol allyl ether (PTAE), 10% acryl alcohol polyoxyethylene ether (APEG), 0.15% dimethacrylate glycerol (GDA), 0.27% triethylene glycol dimethacrylate (TEGDMA), 0.7% diallyl dimethyl ammonium chloride (DMDAAC), and 0.08% ammonium sulfite.

[0249] The preparation method of the above-mentioned NaX molecular sieve-based carbon-fixing concrete internal curing material comprises the following steps:

[0250] Step 1: Weigh the above raw materials by mass;

[0251] Step 2: Slowly add the weighed diatomaceous earth, kaolin, sodium hydroxide and silica sol into deionized water in sequence (mass ratio is diatomaceous earth: kaolin: sodium hydroxide: silica sol: deionized water = 3:1:4:16:800) to dissolve or disperse, and ultrasonically disperse for 30 minutes to obtain suspension A;

[0252] Step 3: Slowly add the weighed NaX molecular sieve seed crystals into the suspension A, pass argon, and stir with a constant temperature magnetic stirrer at a water bath temperature of 25±2°C for 6 hours to obtain a mixed solution B with a mass concentration of 3%;

[0253] Step 4: Transfer the mixed solution B to a sealed polymerization reactor, and perform gelation for 50 min at a microwave power of 120 W. Subsequently, increase the microwave power to 700 W and perform crystallization for 100 min. Cool the obtained product to room temperature, wash it repeatedly with distilled water until it is neutral, dry it in a vacuum oven at 60° C. for 24 h, and then grind it to obtain a NaX molecular sieve material.

[0254] Step 5: The weighed carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate are slowly and evenly dispersed in deionized water in sequence, and magnetically stirred for 30 minutes to prepare a mixed solution C with a mass concentration of 1%;

[0255] Step 6: Use a small amount of deionized water to prepare a mixture D of N-hydroxymethyl acrylamide, pentaerythritol allyl ether (PTAE) and acryl alcohol polyoxyethylene ether (APEG), and transfer the mixture into a brown bottle, store it away from light, and set aside;

[0256] Step 7: Disperse the weighed glycerol dimethacrylate (GDA), triethylene glycol dimethacrylate (TEGDMA) and diallyl dimethyl ammonium chloride (DMDAAC) in deionized water in sequence, stir magnetically for 30 minutes, and prepare a mixed solution E with a concentration of 10%;

[0257] Step 8: Mechanically stir the weighed sorbitan tristearate (Span-65) and cyclohexane in a 45° C. water bath for 40 minutes to form an oil phase after the two are completely mixed;

[0258] Step 9: Slowly add the pre-obtained NaX molecular sieve to the oil phase, pass nitrogen, stir at 300 r / min for 30 min in a 40°C constant temperature water bath environment, and slowly add the pre-selected mixed solution C of carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate and polyvinyl alcohol in sequence during the continuous stirring process; continue stirring for 30 min to obtain a mixed solution F;

[0259] Step 10: slowly add the mixture D to the mixed solution F, the addition time is 4 hours, after the addition is completed, the mixed solution E is added to a four-necked flask, and after 30 minutes, the weighed ammonium sulfite is added, the temperature is controlled between 40°C and 50°C during the whole process, argon is passed, stirring is maintained (speed = 300r / min), and the reaction is continued for 4 hours to obtain the complex G;

[0260] Step 11: Take out the composite G, soak it with isopropanol and wash it 5 times, and after no isopropanol evaporates, obtain the NaX molecular sieve-based carbon-fixing concrete internal curing material.

[0261] Performance Testing

[0262] When in use, the NaX molecular sieve-based carbon-fixing concrete internal curing material is directly ground to 200-250 mesh, and then added to a mixing device together with cement and other cementitious materials for mixing. The maximum liquid absorption rate of the curing material in saturated Ca(OH)2 solution and 0.9%wt CaCl2 solution is tested with reference to the requirements of JC901-2002 "Cement Concrete Curing Agent", JT / T522-2004 "Highway Engineering Concrete Curing Agent" and "Highway Engineering Cement and Cement Concrete Test Procedure" (JTG / E30-2005), as well as the compressive strength ratio test and 28d shrinkage ratio (compared with the benchmark group) test of the concrete after addition. Among them, the dosage is 0.2% of the dosage of the cementitious material. In addition, CO2 is used as the adsorption gas, and 0.2g of the internal curing material is placed in a gas adsorption analyzer to test the CO2 adsorption isotherm of its particles. Specific operation process: the sample is vacuum degassed at 120℃ for 2h, and the CO2 adsorption isotherm of the material is measured at a certain temperature. The pressure range of the isotherm is 0.0~1.0bar.

[0263] The specific performance indicators are as follows:

[0264]

[0265] It can be seen from the above examples that the carbon-fixing concrete curing material based on NaX molecular sieve can not only significantly improve the mechanical strength of concrete, but also exhibit excellent CO2 adsorption performance. The maximum liquid absorption rate of the carbon-fixing concrete curing material in the eight groups of examples in the saturated Ca(OH)2 solution is greater than 65g / g, and the maximum liquid absorption rate in the 0.9%wt CaCl2 solution is greater than 80g / g. Compared with the comparative example, the carbon-fixing concrete curing material in the comparative example has a higher absorption rate in the saturated Ca(OH)2 solution and the 0.9%wt The maximum liquid absorption ratio in the CaCl2 solution decreased significantly; and the addition of the carbon-fixing concrete curing material in the eight groups of examples had a significant improvement effect on the 7d and 28d compressive strength of the concrete, especially the increase in the 28d compressive strength value was more than 10%, and the shrinkage ratio was less than 40%; in addition, the CO2 adsorption capacity of the carbon-fixing concrete curing material in the eight groups of examples was greater than 47%. Compared with the control example, the CO2 adsorption capacity of the embodiment was about 1 to 6 times higher than that of the control example, and the carbon fixation effect was significant, indicating that the lack of materials or the change in proportion, especially the lack of NaX molecular sieve and calcium silicate, significantly affected the carbon fixation effect of the carbon-fixing concrete curing material, while the lack of some organic monomers only had a greater impact on the saturated liquid absorption performance and shrinkage reduction performance of the carbon-fixing concrete curing material. Therefore, the carbon-fixing internal curing material exhibits good liquid absorption characteristics in saline-alkali solutions, and can play a good role in reinforcing and capturing, solidifying and storing CO2. It can also greatly reduce the shrinkage of concrete and has good applicability. It is helpful to promote the green and sustainable development of buildings and the promotion and use of carbon reduction technologies, provide a research basis for building carbon emission reduction, and has broad application prospects.

[0266] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A carbon-fixing concrete internal curing material based on NaX molecular sieve, characterized in that: The invention is prepared from the following raw materials by weight: 15% to 18% of NaX molecular sieve, 8% to 10% of carboxymethyl cellulose, 6% to 8% of bagasse cellulose, 5% to 10% of polyvinyl alcohol, 24% to 30% of N-hydroxymethyl acrylamide, 10% to 15% of maleic anhydride, 3% to 4% of xanthan gum, 2% to 3% of calcium silicate, 8% to 10% of pentaerythritol allyl ether, 10% to 13% of polyoxyethylene propylene alcohol ether, 0.15% to 0.2% of dimethacrylate glyceride, 0.2% to 0.4% of triethylene glycol dimethacrylate, 0.3% to 0.7% of diallyl dimethyl ammonium chloride, 0.08% to 0.5% of ammonium sulfite and 1% to 3% of aqueous ammonia.

2. The carbon-fixing concrete internal curing material based on NaX molecular sieve according to claim 1, characterized in that: The SiO2 / CaO content ratio in the calcium silicate is 0.99-1.15, the sulfate content is less than 0.05%, and the chloride content is less than 0.03%; The carboxymethyl cellulose is food grade, and the content is ≥95%.

3. The carbon-fixing concrete internal curing material based on NaX molecular sieve according to claim 1, characterized in that: The NaX molecular sieve is prepared from the following raw materials: diatomaceous earth, kaolin, NaX molecular sieve seed crystals, sodium hydroxide, silica sol, and deionized water; The process of preparing NaX molecular sieve is as follows: Diatomaceous earth, kaolin, sodium hydroxide and silica sol are sequentially added into deionized water for dispersion and dissolution, and then ultrasonically dispersed to prepare suspension A; NaX molecular sieve seed crystals were added to suspension A, argon was passed through, and magnetic stirring was performed in a water bath at 25±2°C to obtain a mixed solution B with a mass concentration of 3%; The mixed solution B is sealed and then gelled and crystallized in sequence. The obtained product is cooled to room temperature, washed to neutrality, dried, and ground to obtain NaX molecular sieve.

4. The carbon-fixing concrete internal curing material based on NaX molecular sieve according to claim 3, characterized in that: The mass ratio of the diatomaceous earth, kaolin, sodium hydroxide, silica sol and deionized water is 3:1:4:16:

800.

5. The carbon-fixing concrete internal curing material based on NaX molecular sieve according to claim 3, characterized in that: The diatomite has a particle size of 325 mesh, an Al2O3 content of 5.2%, a Fe2O3 content of 1.2%, a pH value of 6 to 8, and a pore volume of 0.45 to 0.98 cm 3 / g, specific surface area is 40~65㎡ / g, adsorption rate ≥300%; The kaolin has a particle size of 800-1500 mesh, an active ingredient content of ≥60%, a silicon dioxide content of ≥50%, and a Mohs hardness of 3-5; The silica sol is a transparent or translucent liquid, the mass fraction of SiO2 in the silica sol is ≥30%, and the pH value is 9-11.

6. The carbon-fixing concrete internal curing material based on NaX molecular sieve according to claim 3, characterized in that: The mixed liquid B is transferred to a polymerization reactor and sealed. The microwave power during gelation is 120W, and the gelation time is 20 to 60 minutes. The microwave power during crystallization is 700W, and the crystallization time is 60 to 120 minutes.

7. A method for preparing a carbon-fixing concrete internal curing material based on NaX molecular sieve according to any one of claims 1 to 6, characterized in that: The following steps are involved: Preparation of NaX molecular sieves; Dispersing carboxymethyl cellulose, bagasse cellulose, xanthan gum and calcium silicate in deionized water to prepare a mixed solution C; Maleic anhydride is prepared into a dilute maleic anhydride solution with deionized water, and then ammonia water is added to neutralize it, and then N-hydroxymethyl acrylamide, pentaerythritol allyl ether and polyoxyethylene propenol ether are added to prepare a mixture D; Dispersing dimethacrylate glycerol, triethylene glycol dimethacrylate and diallyl dimethyl ammonium chloride in deionized water in sequence to prepare a mixed solution E; Sorbitan tristearate and cyclohexane are stirred and mixed to form an oil phase; Adding NaX molecular sieves to the oil phase, stirring and mixing in a constant temperature water bath, and adding the prepared mixed solution C and polyvinyl alcohol during the stirring and mixing process and continuing to stir to prepare a mixed solution F; The mixture D is added dropwise to the mixed solution F, and then the mixed solution E is added, and after a set time, ammonium sulfite is added to carry out a graft polymerization reaction to obtain a composite G; The composite G is immersed and cleaned to prepare a carbon-fixing concrete internal curing material based on NaX molecular sieve.

8. The method for preparing the carbon-fixing concrete internal curing material based on NaX molecular sieve according to claim 7, characterized in that: The mass concentration of the mixed solution C is 1%; the mass concentration of the maleic anhydride dilute solution is 13%; and the mass concentration of the mixed solution E is 10%.

9. The method for preparing the carbon-fixing concrete internal curing material based on NaX molecular sieve according to claim 7, characterized in that: The sorbitan tristearate and cyclohexane are mechanically stirred for 20 to 50 minutes in a water bath at 40 to 45° C. to form an oil phase; The sorbitan tristearate is 1% to 5% of the mass fraction of cyclohexane, and the volume ratio of the oil phase to the water phase is 3 to 5:

1.

10. The method for preparing the carbon-fixing concrete internal curing material based on NaX molecular sieve according to claim 7, characterized in that: The set time is 30 minutes, the reaction temperature of the graft polymerization reaction is 40-50°C, the graft polymerization reaction is carried out under argon conditions, the rotation speed of more than 200r / min is maintained during the graft polymerization reaction, and the time of the graft polymerization reaction is 3-4h.

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