Low-corrosive non-toxic non-sulfur non-alkali accelerator and preparation method thereof

Abstract

The application discloses a low-corrosion non-toxic non-sulfur non-alkali accelerator and a preparation method thereof, and relates to the technical field of concrete admixtures. The accelerator comprises the following components: a main accelerating component, a synergistic accelerating component, a low-corrosion synergistic modifying component, an early-strength enhancing component, a stable dispersing component, a pH regulator, other functional components, a coupling agent and water; the other functional components are prepared by compounding eucommia leaf extract, graphene oxide, Mxene nanosheet, cellulose nanocrystal and rare earth oxide. The accelerator has the advantages of short initial setting time (1:00), 1d compressive strength (27.5 MPa), 28d compressive strength ratio (115.0%), and steel bar weight loss rate (0.017%), and can comprehensively realize the effects of accelerating, early-strengthening and low corrosion, and solve the problems of strong corrosion and single performance of the existing accelerator.

Description

Technical Field

[0001] This invention relates to the field of concrete admixtures, and more particularly to a low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent and its preparation method. Background Technology

[0002] Accelerators are the core admixtures in shotcrete construction. Their main function is to significantly shorten the setting time of cement paste, rapidly form early strength, reduce rebound rate, and ensure the safety and efficiency of construction. Traditional accelerators are mostly alkaline aluminate and water glass systems with high alkali content. Although they have excellent quick-setting effects, they are prone to causing alkali-aggregate reactions in concrete, leading to a significant decrease in strength and structural cracking in the later stages. At the same time, the strong alkalinity can corrode the skin of construction workers and damage equipment and pipelines. They have been gradually replaced by alkali-free accelerators.

[0003] Currently, mainstream alkali-free quick-setting agents use sulfates such as aluminum sulfate and magnesium sulfate as core components. Although this avoids the hazards of alkali metals, it has obvious technical defects: On the one hand, sulfate ions react with calcium ions in cement hydration products to form ettringite, which expands excessively and damages the internal structure of concrete, reducing durability; on the other hand, sulfate-based quick-setting agents have a low pH value and still have strong corrosiveness. Long-term use will corrode spraying equipment and pollute the construction environment. In addition, some products add fluorides and heavy metal salts to improve the quick-setting effect, which poses a toxicity risk and does not meet the requirements of green construction.

[0004] The sulfur-free and alkali-free accelerator technology on the market still has many shortcomings. Most products use aluminum nitrate or aluminum phosphate as the accelerator components, which have insufficient accelerator activity and require a significant increase in dosage to meet the standards. This not only increases costs but also leads to a reduction in the strength of concrete in the later stages. Some products improve performance by compounding with alkanolamines, but alkanolamines are volatile, have poor stability, and are prone to stratification and crystallization when stored at room temperature, and are only compatible with a limited range of cement types. At the same time, existing technologies generally lack low-corrosion modification designs, and the compatibility between accelerators and cement hydration products is poor, making it impossible to balance accelerator performance, low corrosion, and long-term strength stability.

[0005] To address the aforementioned technical problems, invention patent document CN119504171B discloses a low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent and its preparation method. The low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent comprises the following raw materials in parts by weight: 20-30 parts nano-aluminum sol; 15-20 parts silica sol; 8-10 parts bentonite organic copolymer; 10-15 parts aluminum salt; 6-10 parts composite early-strength agent; and 10-15 parts water. The alkali-free quick-setting agent provided by this invention is sulfate-free, non-toxic, and low-corrosion, ensuring safety during storage and use. The addition of bentonite organic copolymer enhances the stability of the alkali-free quick-setting agent. When applied to concrete, it effectively shortens the setting time and improves the early strength and durability of concrete. However, the nano-aluminum sol and silica sol composite system used in this patent is prone to colloidal aggregation, which can lead to gel failure after long-term storage. Furthermore, the bentonite organic copolymer can delay the later hydration of cement, resulting in a slight reduction in the 28-day strength of concrete. At the same time, it has limited corrosion inhibition effect on steel bars and cannot be adapted to key projects with high durability requirements.

[0006] Therefore, developing a quick-setting agent that combines excellent quick-setting performance, low corrosivity, non-toxicity, sulfur-free and alkali-free properties, and strong stability has become an urgent need in the field of shotcrete. Summary of the Invention

[0007] In view of the above, the present invention aims to provide an accelerator with excellent rapid setting performance, low corrosivity, non-toxicity, sulfur-free and alkali-free properties, and strong stability, as well as a method for preparing the same.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent, comprising the following components by weight: 48-52 parts of main quick-setting component, 3.5-5 parts of synergistic quick-setting component, 2.5-3.5 parts of low-corrosion synergistic modifier, 6-7 parts of early-strength enhancing component, 2-3 parts of stabilizing and dispersing component, 1.5-2.5 parts of pH adjuster, 0.8-1.8 parts of other functional components, 0.8-1.2 parts of coupling agent, and 28-35 parts of water; wherein the other functional components are compounded from Eucommia ulmoides leaf extract, graphene oxide, Mxene nanosheets, cellulose nanocrystals, and rare earth oxides in a mass ratio of 1:(0.1-0.2):(0.2-0.3):1:(0.1-0.15).

[0009] Preferably, the main coagulating component is a compound of nano-aluminum sol, nano-silica sol, and β-aminopropionic acid in the ratio of (4.5-5.5):(3.5-4.5):(0.3-0.4).

[0010] Preferably, the nano-aluminum sol is graded VK-L10A; and the nano-silica sol is graded ST-O-40.

[0011] Preferably, the synergistic coagulant component is nano-hydroxyapatite with an average particle size of 40-80 nm.

[0012] Preferably, the low-corrosion synergistic modifying component is a compound of polyepoxysuccinic acid and ethylenediaminetetramethylenephosphonic acid in a mass ratio of (3.5-4.5):1; the relative molecular mass of the polyepoxysuccinic acid is 600-1200.

[0013] Preferably, the early strength enhancing component is at least one of triisopropanolamine and triethanolamine borate.

[0014] Preferably, the stable dispersing component is at least one of carboxymethyl chitosan and sodium alginate.

[0015] Preferably, the degree of substitution of the carboxymethyl chitosan is 90-95%, and the number average molecular weight is 50,000-150,000 Da.

[0016] Preferably, the pH adjuster is at least one of food-grade citric acid and food-grade malic acid.

[0017] Preferably, the particle size of the Eucommia ulmoides leaf extract is 80-100 mesh; the graphene oxide is a single-layer graphene oxide with a sheet diameter of 0.5-5 μm and a thickness of 0.8-1.2 nm; the Mxene nanosheets are single-layer titanium carbide (Ti3C2T) x MXene nanosheets with a diameter of 1-10 μm; the cellulose nanocrystals have a product model of CNC-C99, a diameter of 4-30 nm, and a length of 100-500 nm.

[0018] Preferably, the rare earth oxide is lanthanum oxide with a particle size of 200-500 nm.

[0019] Preferably, the coupling agent is at least one of silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570.

[0020] Another objective of this invention is to provide a method for preparing the low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent, comprising the following steps: mixing the components evenly according to the weight parts, stirring evenly at 45-55°C, adjusting the pH of the system to 6.5-7.5, and passing the mixture through a 100-200 mesh filter to obtain the low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent.

[0021] Due to the application of the above technical solution, the present invention has the following beneficial effects: (1) The low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent and its preparation method disclosed in this invention achieve a dual breakthrough in quick-setting performance and stability through the precise compounding of the main quick-setting component and the synergistic quick-setting component, solving the technical pain points of insufficient quick-setting activity, high dosage required leading to increased cost and subsequent strength reduction of existing sulfur-free and alkali-free quick-setting agents. The main accelerator components, nano-aluminum sol, nano-silica sol, and β-aminopropionic acid, are compounded in a specific ratio to form a synergistic accelerator system. The nano-aluminum sol and nano-silica sol provide sufficient active aluminum and silicon ions to accelerate the hydration reaction of C3A in the cement hydration process, quickly generate hydrated calcium aluminate gel, and shorten the setting time. As an active promoter, β-aminopropionic acid can not only adsorb onto the surface of cement particles and reduce the hydration energy barrier, but also effectively inhibit the colloidal aggregation of nano-aluminum sol and silica sol, avoiding the problem of gel failure during long-term storage in traditional compound systems. The synergistic accelerator component, nano-hydroxyapatite (20-80nm), can fill the pores of cement hydration products. At the same time, its surface hydroxyl groups can form coordination bonds with cement hydration ions, further improving the rapid setting efficiency. Compared with the single aluminum nitrate and aluminum phosphate accelerator system, the initial setting time is shortened and there is no later strength reduction phenomenon under the premise of reduced dosage.

[0022] (2) The low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent and its preparation method disclosed in this invention, with the synergistic effect of low-corrosion synergistic modifier and pH adjuster, achieves precise control of the low corrosivity and non-toxicity of the quick-setting agent, and overcomes the technical defects of existing alkali-free quick-setting agents (sulfate system) with low pH, strong corrosivity, and some products containing fluorides and heavy metal salts. The low-corrosion synergistic modifier is a compound of polyepoxysuccinic acid and ethylenediaminetetramethylenephosphonic acid in a ratio of (3-5):1. The two work synergistically to inhibit corrosion and scale: polyepoxysuccinic acid can form a dense protective film on the surface of steel bars, inhibiting steel bar corrosion, while its non-toxic properties avoid environmental pollution; ethylenediaminetetramethylenephosphonic acid can complex free metal ions in cement, reducing the presence of corrosive ions. The combination of the two can significantly reduce the corrosion rate of quick-setting agents on metal equipment and is non-irritating to the skin; with the addition of food-grade citric acid and malic acid to adjust the pH, it completely avoids the strong corrosiveness of traditional alkaline quick-setting agents and the acidic corrosion problems of sulfate systems, while taking into account the non-toxic, sulfur-free and alkali-free properties, fully meeting the requirements of green construction, and solving the shortcomings of existing technologies that lack low-corrosion modification design and have poor compatibility.

[0023] (3) The low-corrosion, non-toxic, sulfur-free, and alkali-free accelerator and its preparation method disclosed in this invention, through the synergistic effect of the stabilizing dispersant, coupling agent, and other functional components, significantly improve the storage stability of the accelerator and the long-term durability of concrete, solving the problems of easy stratification and crystallization during storage, limited compatibility with cement varieties, and insufficient compatibility with high durability requirements of key projects. The stabilizing dispersant carboxymethyl chitosan (or sodium alginate) and the coupling agent (KH550, etc.) work synergistically. The hydrophilic groups of carboxymethyl chitosan can improve the dispersibility of the system and prevent component agglomeration, while the coupling agent can enhance the interfacial bonding force between each component and cement particles, improve the compatibility of the accelerator with different types of cement, and make the accelerator free from stratification and crystallization after more than 6 months of storage at room temperature, and compatible with various cements such as silicate cement and ordinary silicate cement; other functional components (such as Eucommia ulmoides leaf extract and graphene oxide compounded in a specific ratio) play a synergistic role. Enhancement effect: The active ingredients of Eucommia ulmoides leaf extract can promote the full hydration of cement. Graphene oxide and Mxene nanosheets fill the defects of hydration products with their excellent mechanical properties. Cellulose nanocrystals improve the toughness of the system. Rare earth oxide lanthanum oxide can refine the grains of hydration products. The three work together with early strength enhancing components (such as triisopropanolamine) to not only improve the early strength of concrete, but also significantly improve the 28-day long-term strength of concrete, avoid the later strength reduction, and at the same time improve the impermeability, frost resistance and other durability of concrete and the corrosion inhibition effect of steel bars.

[0024] (4) The low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent and its preparation method disclosed in this invention form an integrated system of "accelerating setting, low corrosion, stabilizing, and enhancing efficiency" through the synergistic effect of each component. Compared with the prior art, this invention achieves a technological breakthrough in terms of excellent quick-setting performance, low corrosion, stable storage, and good long-term strength on the basis of being sulfur-free, alkali-free, non-toxic, and environmentally friendly. It overcomes the technical bottleneck of existing sulfur-free and alkali-free quick-setting agents that cannot take into account multiple performance aspects. Through the precise compounding and synergistic effect of each component, the functions of main quick-setting, synergistic quick-setting, low corrosion modification, and stable dispersion are organically combined, which not only ensures excellent quick-setting effect, but also achieves simultaneous improvement in low corrosion and long-term durability. At the same time, the non-toxic, sulfur-free, and alkali-free characteristics meet the needs of green building development and have significant technological innovation and application value. Detailed Implementation

[0025] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. Example 1

[0026] A low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent comprises the following components by weight: 48 parts of main quick-setting component, 3.5 parts of synergistic quick-setting component, 2.5 parts of low-corrosion synergistic modifier component, 6 parts of early-strength synergistic component, 2 parts of stabilizing and dispersing component, 1.5 parts of pH adjuster, 0.8 parts of other functional components, 0.8 parts of coupling agent, and 28 parts of water; wherein the other functional components are compounded from Eucommia ulmoides leaf extract, graphene oxide, Mxene nanosheets, cellulose nanocrystals, and rare earth oxides in a mass ratio of 1:0.1:0.2:1:0.1.

[0027] The main coagulant component is a compound of nano-aluminum sol, nano-silica sol, and β-aminopropionic acid in a ratio of 4.5:3.5:0.3; the nano-aluminum sol is branded VK-L10A; the nano-silica sol is branded ST-O-40; the synergistic coagulant component is nano-hydroxyapatite with an average particle size of 40 nm; the low-corrosion synergistic modifier component is a compound of polyepoxysuccinic acid and ethylenediaminetetramethylenephosphonic acid in a mass ratio of 3.5:1; the polyepoxysuccinic acid has a relative molecular mass of 600; the early strength synergistic component is triisopropanolamine; the stabilizing and dispersing component is carboxymethyl chitosan with a degree of substitution of 90% and a number average molecular weight of 50,000 Da; and the pH adjuster is food-grade citric acid.

[0028] The eucommia leaf extract has a particle size of 80 mesh; the graphene oxide is a single-layer graphene oxide with a sheet diameter of 0.5~5μm and a thickness of 0.8~1.2nm; the Mxene nanosheets are single-layer titanium carbide (Ti3C2T) x The MXene nanosheets have a diameter of 1-10 μm; the cellulose nanocrystals are product model CNC-C99, with a diameter of 4-30 nm and a length of 100-500 nm; the rare earth oxide is lanthanum oxide with a particle size of 200 nm; and the coupling agent is silane coupling agent KH550.

[0029] A method for preparing the low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent includes the following steps: mixing the components evenly according to the weight parts, stirring evenly at 45°C, adjusting the pH of the system to 6.5, and passing it through a 100-mesh filter to obtain the low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent. Example 2

[0030] A low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent comprises the following components by weight: 49 parts of main quick-setting component, 4 parts of synergistic quick-setting component, 2.8 parts of low-corrosion synergistic modifier component, 6.2 parts of early-strength synergistic component, 2.3 parts of stabilizing and dispersing component, 1.8 parts of pH adjuster, 1 part of other functional components, 0.9 parts of coupling agent, and 30 parts of water; wherein the other functional components are compounded from Eucommia ulmoides leaf extract, graphene oxide, Mxene nanosheets, cellulose nanocrystals, and rare earth oxides in a mass ratio of 1:0.13:0.23:1:0.12.

[0031] The main coagulation accelerator is a compound of nano-aluminum sol, nano-silica sol, and β-aminopropionic acid in a ratio of 4.8:3.8:0.33; the nano-aluminum sol is branded VK-L10A; the nano-silica sol is branded ST-O-40; the synergistic coagulation accelerator is nano-hydroxyapatite with an average particle size of 50 nm; the low-corrosion synergistic modification component is a compound of polyepoxysuccinic acid and ethylenediaminetetramethylenephosphonic acid in a mass ratio of 3.8:1; the relative molecular mass of the polyepoxysuccinic acid is 800; the early strength synergistic component is triethanolamine borate; the stabilizing and dispersing component is sodium alginate; the pH adjuster is food-grade malic acid; the particle size of the Eucommia ulmoides leaf extract is 80-100 mesh; the graphene oxide is a single-layer graphene oxide with a sheet diameter of 0.5-5 μm and a thickness of 0.8-1.2 nm; the Mxene nanosheets are single-layer titanium carbide (Ti3C2T) x The MXene nanosheets have a diameter of 1-10 μm; the cellulose nanocrystals are product model CNC-C99, with a diameter of 4-30 nm and a length of 100-500 nm; the rare earth oxide is lanthanum oxide with a particle size of 300 nm; and the coupling agent is silane coupling agent KH560.

[0032] A method for preparing the low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent includes the following steps: mixing the components evenly according to the weight parts, stirring evenly at 48°C, adjusting the pH of the system to 6.8, and passing it through a 130-mesh filter to obtain the low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent. Example 3

[0033] A low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent comprises the following components by weight: 50 parts of main quick-setting component, 4.3 parts of synergistic quick-setting component, 3 parts of low-corrosion synergistic modifier component, 6.5 parts of early-strength synergistic component, 2.5 parts of stabilizing and dispersing component, 2 parts of pH adjuster, 1.4 parts of other functional components, 1 part of coupling agent, and 31 parts of water; wherein the other functional components are compounded from Eucommia ulmoides leaf extract, graphene oxide, Mxene nanosheets, cellulose nanocrystals, and rare earth oxides in a mass ratio of 1:0.15:0.25:1:0.13.

[0034] The main coagulation accelerator is composed of nano-aluminum sol, nano-silica sol, and β-aminopropionic acid in a ratio of 5:4:0.35; the nano-aluminum sol is designated VK-L10A; the nano-silica sol is designated ST-O-40; the synergistic coagulation accelerator is nano-hydroxyapatite with an average particle size of 60 nm; the low-corrosion synergistic modification component is composed of polyepoxysuccinic acid and ethylenediaminetetramethylenephosphonic acid in a mass ratio of 4:1; the relative molecular mass of the polyepoxysuccinic acid is [missing information]. 900; the early strength synergist is triisopropanolamine; the stabilizing and dispersing component is carboxymethyl chitosan; the degree of substitution of the carboxymethyl chitosan is 93%, and the number average molecular weight is 100,000 Da; the pH adjuster is food-grade citric acid; the particle size of the Eucommia ulmoides leaf extract is 90 mesh; the graphene oxide is a single-layer graphene oxide with a sheet diameter of 0.5~5 μm and a thickness of 0.8~1.2 nm; the Mxene nanosheets are single-layer titanium carbide (Ti3C2T) x The MXene nanosheets have a diameter of 1-10 μm; the cellulose nanocrystals are product model CNC-C99, with a diameter of 4-30 nm and a length of 100-500 nm; the rare earth oxide is lanthanum oxide with a particle size of 350 nm; and the coupling agent is silane coupling agent KH570.

[0035] A method for preparing the low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent includes the following steps: mixing each component evenly according to the weight parts, stirring evenly at 50°C, adjusting the pH of the system to 7, and passing it through a 150-mesh filter to obtain the low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent. Example 4

[0036] A low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent comprises the following components by weight: 51 parts of main quick-setting component, 4.8 parts of synergistic quick-setting component, 3.3 parts of low-corrosion synergistic modifier component, 6.8 parts of early-strength synergistic component, 2-3 parts of stabilizing and dispersing component, 1.5-2.5 parts of pH adjuster, 0.8-1.8 parts of other functional components, 0.8-1.2 parts of coupling agent, and 28-35 parts of water; wherein the other functional components are compounded from Eucommia ulmoides leaf extract, graphene oxide, Mxene nanosheets, cellulose nanocrystals, and rare earth oxides in a mass ratio of 1:0.18:0.28:1:0.14.

[0037] The main coagulant component is a compound of nano-aluminum sol, nano-silica sol, and β-aminopropionic acid in a ratio of 5.3:4.3:0.38; the nano-aluminum sol is branded VK-L10A; the nano-silica sol is branded ST-O-40; the synergistic coagulant component is nano-hydroxyapatite with an average particle size of 70 nm; the low-corrosion synergistic modifier component is a compound of polyepoxysuccinic acid and ethylenediaminetetramethylenephosphonic acid in a mass ratio of 4.3:1; the polyepoxysuccinic acid has a relative molecular mass of 1100; the early strength synergistic component is a compound of triisopropanolamine and triethanolamine borate in a mass ratio of 1:2; the stabilizing and dispersing component is a compound of carboxymethyl chitosan and sodium alginate in a mass ratio of 3:5; the carboxymethyl chitosan has a degree of substitution of 94% and a number average molecular weight of 140,000 Da; the pH adjuster is a compound of food-grade citric acid and food-grade malic acid in a mass ratio of 1:1.

[0038] The eucommia leaf extract has a particle size of 95 mesh; the graphene oxide is a single-layer graphene oxide with a sheet diameter of 0.5~5μm and a thickness of 0.8~1.2nm; the Mxene nanosheets are single-layer titanium carbide (T... i3 C2T x The MXene nanosheets have a diameter of 1-10 μm; the cellulose nanocrystals are product model CNC-C99, with a diameter of 4-30 nm and a length of 100-500 nm; the rare earth oxide is lanthanum oxide with a particle size of 450 nm; the coupling agent is a compound of silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570 in a mass ratio of 1:2:3.

[0039] A method for preparing the low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent includes the following steps: mixing each component evenly according to the weight parts, stirring evenly at 53°C, adjusting the pH of the system to 7.3, and passing it through a 180-mesh filter to obtain the low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent. Example 5

[0040] A low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent comprises the following components by weight: 52 parts of main quick-setting component, 5 parts of synergistic quick-setting component, 3.5 parts of low-corrosion synergistic modifier component, 7 parts of early-strength synergistic component, 3 parts of stabilizing and dispersing component, 2.5 parts of pH adjuster, 1.8 parts of other functional components, 1.2 parts of coupling agent, and 35 parts of water; wherein the other functional components are compounded from Eucommia ulmoides leaf extract, graphene oxide, Mxene nanosheets, cellulose nanocrystals, and rare earth oxides in a mass ratio of 1:0.2:0.3:1:0.15.

[0041] The main coagulation-promoting component is a compound of nano-aluminum sol, nano-silica sol, and β-aminopropionic acid in a ratio of 5.5:4.5:0.4; the nano-aluminum sol is branded VK-L10A; the nano-silica sol is branded ST-O-40; the synergistic coagulation-promoting component is nano-hydroxyapatite with an average particle size of 80 nm; the low-corrosion synergistic modifying component is a compound of polyepoxysuccinic acid and ethylenediaminetetramethylenephosphonic acid in a mass ratio of 4.5:1; the relative molecular mass of the polyepoxysuccinic acid is [missing information]. 1200; the early strength synergist is triisopropanolamine; the stabilizing and dispersing component is carboxymethyl chitosan; the degree of substitution of the carboxymethyl chitosan is 95%, and the number average molecular weight is 150,000 Da; the pH adjuster is food-grade citric acid; the particle size of the Eucommia ulmoides leaf extract is 80-100 mesh; the graphene oxide is a single-layer graphene oxide with a sheet diameter of 0.5-5 μm and a thickness of 0.8-1.2 nm; the Mxene nanosheets are single-layer titanium carbide (Ti3C2T) x The MXene nanosheets have a diameter of 1-10 μm; the cellulose nanocrystals are product model CNC-C99, with a diameter of 4-30 nm and a length of 100-500 nm; the rare earth oxide is lanthanum oxide with a particle size of 500 nm; and the coupling agent is silane coupling agent KH550.

[0042] A method for preparing the low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent includes the following steps: mixing the components evenly according to the weight parts, stirring evenly at 55°C, adjusting the pH of the system to 7.5, and passing it through a 200-mesh filter to obtain the low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent.

[0043] Comparative Example 1 A low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent and its preparation method are basically the same as those in Example 5, except that β-aminopropionic acid is not added.

[0044] Comparative Example 2 A low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent and its preparation method are basically the same as those in Example 5, except that an equal amount of Eucommia ulmoides leaf extract is used instead of cellulose nanocrystals.

[0045] Comparative Example 3 A low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent and its preparation method are basically the same as those in Example 5, except that an equal amount of cellulose nanocrystals are used instead of Eucommia ulmoides leaf extract.

[0046] Comparative Example 4 A low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent and its preparation method are basically the same as those in Example 5, except that an equal amount of Mxene nanosheets are used instead of rare earth oxides.

[0047] Comparative Example 5 A low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent and its preparation method are basically the same as those in Example 5, except that an equal amount of rare earth oxides are used instead of Mxene nanosheets.

[0048] The low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agents of Examples 5 and Comparative Examples 1-5 were subjected to relevant performance tests. The test results are shown in Table 1. The test methods are as follows: Referencing GB / T 35159-2017 "Quick-setting Agents for Shotcrete", GB / T 50082-2009 "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete", and GB / T 46613-2025 "Corrosion of Metals and Alloys - Determination and Evaluation Method of Steel Corrosion in Concrete Structures in Full Corrosion Zones of Marine Environments", the test items included setting time, compressive strength, steel corrosion rate, and storage stability. The dosage was uniformly 6% of the cement mass. Cement code: P.O42.5. All test samples were finished products prepared in Examples 5 and the comparative examples. The steel weight loss rate was the steel weight loss rate after 28 days of curing.

[0049] Table 1. Performance test results of low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agents. As can be seen from the data in Table 1, the low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent of this invention, through the synergistic effect of a specific ratio of main quick-setting components (nano-aluminum sol, nano-silica sol, and β-aminopropionic acid compound), synergistic quick-setting components, low-corrosion synergistic modifying components, and other specifically compounded functional components (Eucommia ulmoides leaf extract, graphene oxide, Mxene nanosheets, cellulose nanocrystals, and rare earth oxides), exhibits superior quick-setting effect (initial setting time as short as 1:00), higher early and long-term strength (1-day compressive strength reaches 27.5 MPa, and 28-day compressive strength ratio reaches 115.0%), and lower steel corrosion (steel weight loss rate is only 0.017%). Moreover, the synergistic effect of each component is indispensable, ultimately achieving comprehensive performance optimization of quick setting, early strength, low corrosion, and stable dispersion.

[0050] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent, characterized in that, It comprises the following components by weight: 48-52 parts of main coagulant, 3.5-5 parts of synergistic coagulant, 2.5-3.5 parts of low-corrosion synergistic modifier, 6-7 parts of early strength enhancing component, 2-3 parts of stabilizing and dispersing component, 1.5-2.5 parts of pH adjuster, 0.8-1.8 parts of other functional components, 0.8-1.2 parts of coupling agent, and 28-35 parts of water; the other functional components are compounded from Eucommia ulmoides leaf extract, graphene oxide, Mxene nanosheets, cellulose nanocrystals, and rare earth oxides in a mass ratio of 1:(0.1-0.2):(0.2-0.3):1:(0.1-0.15).

2. The low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent according to claim 1, characterized in that, The main coagulating component is a compound of nano-aluminum sol, nano-silica sol, and β-aminopropionic acid in the ratio of (4.5-5.5):(3.5-4.5):(0.3-0.4).

3. The low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent according to claim 2, characterized in that, The nano-aluminum sol is designated as VK-L10A; the nano-silica sol is designated as ST-O-40.

4. The low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent according to claim 1, characterized in that, The synergistic coagulant component is nano-hydroxyapatite with an average particle size of 40-80 nm.

5. The low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent according to claim 1, characterized in that, The low-corrosion synergistic modification component is a compound of polyepoxysuccinic acid and ethylenediaminetetramethylenephosphonic acid in a mass ratio of (3.5-4.5):1; the relative molecular mass of the polyepoxysuccinic acid is 600-1200.

6. The low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent according to claim 1, characterized in that, The early strength enhancing component is at least one of triisopropanolamine and triethanolamine borate; the stabilizing dispersing component is at least one of carboxymethyl chitosan and sodium alginate.

7. The low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent according to claim 1, characterized in that, The degree of substitution of the carboxymethyl chitosan is 90-95%, and the number average molecular weight is 50,000-150,000 Da; the pH adjuster is at least one of food-grade citric acid and food-grade malic acid.

8. The low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent according to claim 1, characterized in that, The eucommia leaf extract has a particle size of 80-100 mesh; the graphene oxide is a single-layer graphene oxide with a sheet diameter of 0.5-5 μm and a thickness of 0.8-1.2 nm; the Mxene nanosheets are single-layer titanium carbide (Ti3C2T) x MXene nanosheets with a diameter of 1-10 μm; the cellulose nanocrystals have a product model of CNC-C99, a diameter of 4-30 nm, and a length of 100-500 nm.

9. The low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent according to claim 1, characterized in that, The rare earth oxide is lanthanum oxide with a particle size of 200-500 nm; the coupling agent is at least one of silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570.

10. A method for preparing a low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent according to any one of claims 1-9, characterized in that, The process includes the following steps: mixing each component evenly according to the weight proportions, stirring evenly at 45-55℃, adjusting the pH of the system to 6.5-7.5, and passing it through a 100-200 mesh filter to obtain a low-corrosion, non-toxic, sulfur-free, and alkali-free quick-setting agent.

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