Nanometer reinforced quick-setting viscosity agent and its application in concrete

Abstract

The application discloses a nano-enhanced quick-setting viscosity increasing agent and application thereof in concrete. The quick-setting viscosity increasing agent comprises an aluminum salt quick-setting component, surface modified nano-silica, an ion triggered viscosity increasing polymer, an organic acid stabilizing component and water. The quick-setting viscosity increasing agent can be stably dispersed under acidic storage conditions, and after being contacted with a cement-based material, a viscosity increasing network is formed under an alkaline environment and the action of Ca2+, so that quick setting and viscosity increasing are synergized. The surface modified nano-silica has good dispersion stability and nucleation promoting effect, and the ion triggered viscosity increasing polymer can quickly improve the cohesiveness of a paste and the structure establishment speed. The prepared quick-setting viscosity increasing agent has the advantages of good storage stability, fast setting speed, strong wall hanging property, low rebound rate and good strength maintenance, and can be applied to sprayed concrete, sprayed mortar, quick repair mortar and facade printing cement-based materials.

Description

Technical Field

[0001] This invention relates to the field of advanced inorganic non-metallic materials technology, and in particular to a nano-reinforced quick-setting thickener and its application in concrete. Background Technology

[0002] In recent years, quick-setting thickeners have been widely used in shotcrete, shotcrete, quick-repair mortar, and cement-based materials for facade molding. Their function is to improve the cohesiveness, anti-sagging, and wall-hanging properties of the slurry while ensuring rapid setting and hardening, thereby reducing rebound rate, segregation, and improving construction quality. Existing quick-setting thickeners mostly use aluminum salt quick-setting components combined with organic polymer thickeners or inorganic thickeners. However, they generally suffer from insufficient storage stability, limited thickening efficiency, poor compatibility with quick-setting components, and a narrow viscosity control range, making it difficult to simultaneously achieve pumpability, quick setting, and construction adaptability.

[0003] With the development of nanomaterials and responsive materials, constructing rapid-setting and thickening systems using nano-reinforcing components and ion-triggered thickening components has become an important direction in this field. Nano-silica, nano-calcium silicate, and nano-seed materials have advantages such as large specific surface area, high activity, and strong nucleation effect, which can promote early hydration and structure establishment of cement. Ion-triggered thickening polymers can undergo conformational extension, ionic cross-linking, or structural reconstruction under specific ionic environments or pH changes, thereby realizing the transformation from a low-viscosity storage state to a high-viscosity use state, improving the thickening efficiency and rapid-setting effect after being added to the mortar.

[0004] However, existing nano-reinforced rapid-setting thickening systems still have shortcomings: nano-components tend to aggregate and precipitate in high-salt, acidic, or multi-ionic environments, resulting in poor storage stability; while some ion-triggered thickening systems exhibit responsive characteristics, the triggering conditions are difficult to control, and the synergy between the nano-component and the rapid-setting component is insufficient, easily leading to problems such as excessive viscosity in the early stage, instability in the later stage, or significant strength loss. Therefore, developing a nano-reinforced rapid-setting thickener that is storage-stable, trigger-sensitive, and possesses both rapid-setting and thickening synergistic effects remains of great significance. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a nano-reinforced quick-setting and thickening agent and its application in concrete. This quick-setting and thickening agent is composed of an aluminum salt quick-setting component, surface-modified nano-silica, an ion-triggered thickening polymer, an organic acid stabilizing component, and water. This quick-setting and thickening agent maintains stable dispersion under acidic storage conditions and, upon contact with cementitious materials, forms a thickening network under alkaline conditions and the action of Ca2+, thereby achieving a synergistic effect of quick setting and thickening.

[0006] This invention can be achieved through the following technical solutions: A nano-reinforced quick-setting and thickening agent comprises, by total mass percentage, the following components: 30%-55% aluminum salt quick-setting component, 1%-10% surface-modified nano silica, 0.1%-5% ion-triggered thickening polymer, 1%-10% organic acid stabilizing component, and the balance being water; wherein the surface-modified nano silica remains stably dispersed under acidic storage conditions, and upon contact with cementitious materials, synergistically forms a three-dimensional thickening network with the ion-triggered thickening polymer under alkaline conditions and the action of Ca2+ and Al3+, thereby achieving quick setting and thickening.

[0007] Preferably, the aluminum salt quick-setting component is a combination of polyaluminum sulfate and aluminum sulfate, wherein the mass ratio of polyaluminum sulfate to aluminum sulfate is (1-5):1.

[0008] Preferably, the surface-modified nano-silica is added in the form of a dispersion, with an average particle size of 10-50 nm, and the surface contains carboxyl, hydroxyl, or amino groups.

[0009] Preferably, the ion-triggered thickening polymer is added in the form of an emulsion and is selected from acrylic acid-acrylamide copolymers, alginate, or xanthan gum modifiers.

[0010] Preferably, the organic acid stabilizing component is selected from citric acid, tartaric acid, or formic acid.

[0011] Preferably, the storage pH of the quick-setting thickener is 1-5.

[0012] Preferably, the preparation method of the nano-reinforced quick-setting thickener is as follows: aluminum salt quick-setting component is added to water and stirred to dissolve. Organic acid stabilizing component, surface-modified nano silica and ion-triggered thickening polymer are added at 15-35℃. Stirring is continued until the system is uniform to obtain nano-reinforced quick-setting thickener.

[0013] Application of a nano-reinforced quick-setting tackifier in shotcrete, shotcrete mortar, quick-repair mortar or cement-based materials for vertical printing.

[0014] Preferably, when the nano-reinforced quick-setting thickener is used in shotcrete or shotcrete, it can improve the adhesion of the slurry to the wall and reduce the rebound rate of the spray.

[0015] The beneficial effects of this invention are: This invention organically combines aluminum salt-based quick-setting components, surface-modified nano-silica, ion-triggered thickening polymers, and organic acid-stabilizing components to construct a composite system that combines storage stability, rapid response, and construction adaptability. This technical solution combines stable dispersion under acidic storage conditions with structural reconstruction under alkaline and calcium ion environments after slurry application, enabling synergistic effects of quick-setting and thickening within the same system. Surface-modified nano-silica maintains good dispersion within the system and provides active nucleation sites for early cement hydration; the ion-triggered thickening polymer undergoes rapid conformational changes, ionic crosslinking, or network association upon contact with cementitious materials, forming a microscopic thickening network conducive to slurry structure establishment. Thus, this invention achieves an effective transformation from "stable in storage" to "rapid thickening in use," ensuring good adaptability of the product in transportation, storage, and construction stages.

[0016] The quick-setting thickener of this invention exhibits both rapid setting and hardening speed and strong slurry cohesion during application, which is beneficial for improving the slurry's wall adhesion, anti-sagging properties, and molding stability. Due to the significant synergistic effect between the nano-reinforcing components and the ion-triggered thickening components, the slurry can establish an early structure more quickly after contacting the cement system, thereby effectively reducing the rebound rate during spraying and improving material adhesion and construction quality. Simultaneously, the nano-components promote the cement hydration process, further improving the early strength of the material and maintaining good mechanical properties in the later stages. This makes the resulting system suitable not only for sprayed concrete and sprayed mortar applications requiring rapid support and molding, but also for quick-repair mortar and vertical printing cement-based materials applications that demand both rapid setting and thickening. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 The initial setting time, final setting time, 30-day deposition layer height ratio, 28-day compressive strength, and spray rebound rate of the quick-setting thickener were measured. Detailed Implementation

[0018] The following provides a detailed description of the embodiments of the present invention: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and processes. However, the scope of protection of the present invention is not limited to the following embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0019] Example 1: A nano-reinforced quick-setting tackifier, based on a total mass of 1 kg, comprises the following components: 300 g of aluminum salt quick-setting component (composed of polyaluminum sulfate and aluminum sulfate in a mass ratio of 1:1), 10 g of surface-modified nano silica (average particle size of 10 nm, containing carboxyl groups on the surface), 1 g of ion-triggered tackifying polymer (acrylic acid-acrylamide copolymer), 10 g of organic acid stabilizing component (citric acid), and 679 mL of water.

[0020] A method for preparing a nano-reinforced quick-setting and thickening agent is as follows: An aluminum salt quick-setting component is added to water and stirred to dissolve. An organic acid stabilizing component, a surface-modified nano-silica dispersion, and an ion-triggered thickening polymer emulsion are then added at 15°C. The mixture is stirred until homogeneous to obtain the nano-reinforced quick-setting and thickening agent. The obtained quick-setting and thickening agent, when stored sealed at pH 1 and room temperature, exhibits good storage stability without significant stratification, sedimentation, or crystallization. When used in cementitious materials, under the alkaline environment of the slurry and the action of Ca2+, the surface-modified nano-silica and the ion-triggered thickening polymer synergistically form a thickening network, thereby achieving a synergistic effect of quick setting and thickening.

[0021] Example 2: A nano-reinforced quick-setting thickener, based on a total mass of 1 kg, comprises the following components: 425 g of aluminum salt quick-setting component (composed of polyaluminum sulfate and aluminum sulfate in a mass ratio of 3:1), 55 g of surface-modified nano silica (average particle size of 30 nm, containing hydroxyl groups on the surface), 25 g of ion-triggered thickening polymer (alginate), 55 g of organic acid stabilizing component (tartaric acid), and 440 mL of water.

[0022] A method for preparing a nano-reinforced quick-setting and thickening agent is as follows: An aluminum salt quick-setting component is added to water and stirred to dissolve. An organic acid stabilizing component, a surface-modified nano-silica dispersion, and an ion-triggered thickening polymer emulsion are then added at 25°C. The mixture is stirred until homogeneous to obtain the nano-reinforced quick-setting and thickening agent. The resulting quick-setting and thickening agent, when stored sealed at pH 3 and room temperature, exhibits good storage stability without significant stratification, sedimentation, or crystallization. When used in cementitious materials, under the alkaline environment of the slurry and the action of Ca2+, the surface-modified nano-silica and the ion-triggered thickening polymer synergistically form a thickening network, thereby achieving a synergistic effect of quick setting and thickening.

[0023] Example 3: A nano-reinforced quick-setting thickener, based on a total mass of 1 kg, comprises the following components: 550 g of aluminum salt quick-setting component (composed of polyaluminum sulfate and aluminum sulfate in a mass ratio of 5:1), 100 g of surface-modified nano silica (average particle size of 50 nm, containing amino groups on the surface), 50 g of ion-triggered thickening polymer (xanthan gum modifier), 100 g of organic acid stabilizing component (formic acid), and 200 mL of water.

[0024] A method for preparing a nano-reinforced quick-setting and thickening agent is as follows: An aluminum salt quick-setting component is added to water and stirred to dissolve. An organic acid stabilizing component, a surface-modified nano-silica dispersion, and an ion-triggered thickening polymer emulsion are then added at 35°C. The mixture is stirred until homogeneous to obtain the nano-reinforced quick-setting and thickening agent. The obtained quick-setting and thickening agent, when stored sealed at pH 5 and room temperature, exhibits good storage stability without significant stratification, sedimentation, or crystallization. When used in cementitious materials, under the alkaline environment of the slurry and the action of Ca2+, the surface-modified nano-silica and the ion-triggered thickening polymer synergistically form a thickening network, thereby achieving a synergistic effect of quick setting and thickening.

[0025] Example 4: A nano-reinforced quick-setting thickener, based on a total mass of 1 kg, comprises the following components: 300 g of aluminum salt quick-setting component (composed of polyaluminum sulfate and aluminum sulfate in a mass ratio of 3:1), 100 g of surface-modified nano silica (average particle size of 10 nm, containing carboxyl groups on the surface), 50 g of ion-triggered thickening polymer (alginate), 10 g of organic acid stabilizing component (citric acid), and 540 mL of water.

[0026] A method for preparing a nano-reinforced quick-setting and thickening agent is as follows: An aluminum salt quick-setting component is added to water and stirred to dissolve. An organic acid stabilizing component, a surface-modified nano-silica dispersion, and an ion-triggered thickening polymer emulsion are then added at 35°C. The mixture is stirred until homogeneous to obtain the nano-reinforced quick-setting and thickening agent. The obtained quick-setting and thickening agent, when stored sealed at pH 3 and room temperature, exhibits good storage stability without significant stratification, sedimentation, or crystallization. When used in cementitious materials, under the alkaline environment of the slurry and the action of Ca2+, the surface-modified nano-silica and the ion-triggered thickening polymer synergistically form a thickening network, thereby achieving a synergistic effect of quick setting and thickening.

[0027] Comparative Example 1: The difference between this comparative example and Example 1 is that no surface-modified nano silica dispersion is added.

[0028] A quick-setting thickener, based on a total mass of 1 kg, comprises the following components: 300 g of an aluminum salt quick-setting component (composed of polyaluminum sulfate and aluminum sulfate in a mass ratio of 1:1), 1 g of an ion-triggered thickening polymer (acrylic acid-acrylamide copolymer), 10 g of an organic acid stabilizing component (citric acid), and 679 mL of water.

[0029] A method for preparing a quick-setting thickener is as follows: add an aluminum salt quick-setting component to water, stir to dissolve, add an organic acid stabilizing component and an ion-triggered thickening polymer emulsion at 15°C, and continue stirring until the system is homogeneous to obtain the quick-setting thickener.

[0030] Comparative Example 2: The difference between this comparative example and Example 1 is that no ion-triggered thickening polymer emulsion is added.

[0031] A nano-reinforced quick-setting thickener, based on a total mass of 1 kg, comprises the following components: 300 g of aluminum salt quick-setting component (composed of polyaluminum sulfate and aluminum sulfate in a mass ratio of 1:1), 10 g of surface-modified nano silica (average particle size of 10 nm, containing carboxyl groups on the surface), 10 g of organic acid stabilizing component (citric acid), and 679 mL of water.

[0032] A method for preparing a nano-reinforced quick-setting thickener is as follows: aluminum salt quick-setting components are added to water and stirred to dissolve. Organic acid stabilizing components and surface-modified nano silica dispersions are added at 15°C. The mixture is stirred until the system is homogeneous to obtain the nano-reinforced quick-setting thickener.

[0033] Comparative Example 3: The difference between this comparative example and Example 1 is that unmodified nano silica dispersion is used instead of surface-modified silica dispersion.

[0034] A nano-reinforced quick-setting thickener, based on a total mass of 1 kg, comprises the following components: 300 g of aluminum salt quick-setting component (composed of polyaluminum sulfate and aluminum sulfate in a mass ratio of 1:1), 10 g of unmodified nano silica dispersion (average particle size of 10 nm, containing carboxyl groups on the surface), 1 g of ion-triggered thickening polymer (acrylic acid-acrylamide copolymer), 10 g of organic acid stabilizing component (citric acid), and 679 mL of water.

[0035] A method for preparing a nano-reinforced quick-setting thickener is as follows: aluminum salt quick-setting component is added to water and stirred to dissolve. Organic acid stabilizing component, unmodified nano silica dispersion and ion-triggered thickening polymer emulsion are added at 15°C. Stirring is continued until the system is homogeneous to obtain the nano-reinforced quick-setting thickener.

[0036] Performance testing 1. Condensation Time Test The setting time of the quick-setting thickener was tested in accordance with the GB / T 1346-2024 standard.

[0037] 2 Storage stability The storage stability of the quick-setting thickener was tested according to GB / T 8077-2023 standard. The prepared quick-setting thickener sample was transferred to a 250mL graduated cylinder, sealed, and allowed to stand at 20±2℃ for 1 day, 7 days, and 30 days. At each time point, the sample was observed for stratification, sedimentation, crystallization, or obvious flocculation. The pH value and density of the supernatant and the overall sample were also measured.

[0038] 3. Compressive strength test The compressive strength of the quick-setting thickener was tested in accordance with the GB / T 17671-2021 standard.

[0039] 4. Spray rebound rate test The spray rebound rate of the quick-setting thickener was tested in accordance with the NB / T 11535-2024 standard.

[0040] Table 1 Performance test results of quick-setting thickeners

[0041] As shown in Table 1, all nano-reinforced quick-setting and thickening agents prepared in the examples exhibited shorter initial and final setting times, indicating that the introduction of surface-modified nano-silica can effectively promote the early-stage structure establishment of the cement system and form a synergistic effect with the aluminum salt quick-setting components, thereby improving the quick-setting effect. Furthermore, the 30-day deposition layer height was lower, and the storage stability was better, indicating that surface-modified nano-silica has better dispersion stability and system compatibility compared to unmodified nano-silica. Simultaneously, the 28-day compressive strength of all examples was higher than that of all comparative examples, and the spray rebound rate was significantly reduced, indicating that surface-modified nano-silica and ion-triggered thickening polymers have a good synergistic effect, achieving a synergistic effect of quick-setting and thickening while ensuring storage stability.

[0042] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A nano-reinforced rapid-setting thickener, characterized in that, The product comprises the following components by total mass percentage: 30%-55% aluminum salt quick-setting component, 1%-10% surface-modified nano silica, 0.1%-5% ion-triggered thickening polymer, 1%-10% organic acid stabilizing component, and the balance being water; wherein the surface-modified nano silica remains stably dispersed under acidic storage conditions, and upon contact with cement-based materials, it synergistically forms a three-dimensional thickening network with the ion-triggered thickening polymer under alkaline conditions and the action of Ca2+ and Al3+, thereby achieving quick setting and thickening.

2. The nano-reinforced rapid-setting thickener according to claim 1, characterized in that, The aluminum salt quick-setting component is a combination of polyaluminum sulfate and aluminum sulfate, wherein the mass ratio of polyaluminum sulfate to aluminum sulfate is (1-5):

1.

3. The nano-reinforced rapid-setting thickener according to claim 1, characterized in that, The surface-modified nano-silica is added in the form of a dispersion, with an average particle size of 10-50 nm, and the surface contains carboxyl, hydroxyl or amino groups.

4. The nano-reinforced rapid-setting thickener according to claim 1, characterized in that, The ion-triggered thickening polymer is added in emulsion form and is selected from acrylic acid-acrylamide copolymers, alginate, or xanthan gum modifiers.

5. The nano-reinforced rapid-setting thickener according to claim 1, characterized in that, The organic acid stabilizing component is selected from citric acid, tartaric acid, or formic acid.

6. The nano-reinforced rapid-setting thickener according to claim 1, characterized in that, The storage pH of the quick-setting thickener is 1-5.

7. The nano-reinforced rapid-setting thickener according to any one of claims 1-6, characterized in that, The preparation method of the nano-reinforced quick-setting thickener is as follows: add aluminum salt quick-setting components to water, stir to dissolve, add organic acid stabilizing components, surface-modified nano silica and ion-triggered thickening polymer at 15-35℃, and continue stirring until the system is uniform to obtain the nano-reinforced quick-setting thickener.

8. The application of the nano-reinforced quick-setting tackifier according to any one of claims 1-7 in shotcrete, shotcrete mortar, quick-repair mortar or cement-based materials for vertical printing.

9. The application according to claim 8, characterized in that, When the nano-reinforced quick-setting thickener is used in shotcrete or shotcrete, it can improve the adhesion of the slurry to the wall and reduce the rebound rate of the spray.

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