Nano-modified composite cementing material

Abstract

The invention provides a nano modified composite cementing material, which relates to the technical field of cementing materials, and comprises the following components: slag, construction waste powder, a nano material, an alkali activator and water. By introducing the nano material, the pore structure of the solid waste-based material is remarkably improved, and the gelling capacity, mechanical property and durability of the solid waste-based material are improved. Meanwhile, the material also has relatively strong crack resistance, and the photocatalytic performance and the self-cleaning function of the material can be improved by introducing a functional nano material.

Description

Technical Field

[0001] The invention relates to the technical field of gelling materials, in particular to a nano-modified composite gelling material. Background Art

[0002] With the rapid development of the construction industry, a large amount of construction waste and industrial solid waste (such as slag) is continuously generated, which has brought great pressure to the environment. Although traditional cement-based materials have excellent performance, the emission of carbon dioxide during the production process is relatively high. In order to reduce carbon emissions and enhance the sustainability of building materials, the resource utilization of solid waste materials such as slag and construction waste has become a research hotspot. However, the performance of slag and construction waste powder alone as cementitious materials is often not as good as that of traditional cement, especially the mechanical properties and durability are poor.

[0003] In recent years, nanomaterials have been gradually introduced into the field of building materials due to their unique microstructure regulation capabilities. Nanoparticles can not only fill the micropores in the material and reduce the porosity, but also enhance the mechanical properties of cementitious materials through interfacial effects. Combining the characteristics of nanomaterials with the efficient utilization of solid waste resources, optimizing the microstructure of composite cementitious materials has become a technical problem that needs to be solved urgently. Summary of the invention

[0004] In view of the above-mentioned prior art, the present invention proposes a nano-modified composite gelling material.

[0005] The invention provides a nano-modified composite gelling material, which comprises the following components: slag, building waste powder, nano-material, alkali activator and water.

[0006] Preferably, in parts by weight, the slag is 50-70 parts, the construction waste powder is 30-50 parts, the nano material is 1-5 parts, and the alkali activator is 5-7 parts.

[0007] Preferably, the nanomaterial is nano-silicon dioxide or nano-titanium dioxide or nano-cellulose.

[0008] Preferably, the alkaline activator is at least one of sodium hydroxide and sodium silicate.

[0009] Preferably, the preparation process comprises the following steps: S1. Grind the slag and construction waste powder to a fineness of 4000-5000cm² / g to increase its reactivity; S2, uniformly mixing the nanomaterials with slag and construction waste powder to form a matrix material; S3, adding an alkali activator to the matrix material to further improve the activity of slag and construction waste powder; S4. Add water and stir thoroughly to ensure that the materials are evenly mixed to form a gelled slurry.

[0010] Preferably, the method further comprises S5, casting the gelling slurry into a shape, curing or carbonizing the slurry at room temperature after curing, so as to further enhance the performance of the material.

[0011] The present invention can significantly improve the performance of composite cementitious materials through the following physical and chemical mechanisms: (1) Filling effect: Nanomaterial particles are extremely fine (usually at the nanometer level) and can effectively fill the tiny pores in slag and construction waste powder materials, reduce porosity, and increase the density of the materials. Nano-silicon dioxide and nano-titanium dioxide, due to their large specific surface area, can act as "filling" materials in the microstructure of the material, optimize the internal structure, and make the material denser.

[0012] (2) Interface effect: Nanomaterials have a high specific surface area and can form strong interface bonds with the generated CSH gel (calcium silicate hydrate) and NASH gel (sodium aluminum silicate hydrate) under alkaline excitation. These interface regions provide additional mechanical bonding force, effectively improving the strength and toughness of the material.

[0013] (3) Activity of nanomaterials: Nano-silicon dioxide and nano-titanium dioxide show high reactivity in alkaline environments. Nano-silicon dioxide can accelerate the formation process of CSH gel and shorten the coagulation and hardening time of the material; nano-titanium dioxide has good catalytic activity and can further optimize the reaction rate of the material. In addition, photocatalytic nano-titanium dioxide can also give the material self-cleaning ability, allowing it to degrade surface organic matter under sunlight.

[0014] (4) Synergistic effect of alkali activation and carbonization reaction: The active components in slag and construction waste powder are dissolved under the action of alkali activator, releasing Ca2⁺, SiO 4 4 ⁻ and AlO 4 5 ⁻, these ions combine to form CSH and NASH gels. Through subsequent carbonization, the residual Ca(OH) 2 With CO 2 The reaction produces CaCO 3 , further improving the strength and density of the material.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention proposes a nano-modified composite cementitious material, which combines nano-material modification technology with solid waste-based composite cementitious materials, and innovatively utilizes the filling effect, interface effect and high activity of nano-particles to improve the cementitious properties of slag and construction waste powder. Through the combination of alkali excitation and carbonization reaction, both the early strength of the material and its long-term durability are enhanced. The introduction of nano-titanium dioxide gives the material a photocatalytic self-cleaning function, which helps to keep it clean for a long time in applications such as building exterior walls. Therefore, the present invention utilizes the combination of slag and construction waste powder, and through the microstructure optimization of nano-materials and the synergistic effect of alkali excitation and carbonization reaction, it significantly improves the mechanical properties, crack resistance and durability of the material, and has broad application prospects. DETAILED DESCRIPTION

[0016] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments.

[0017] Example 1: A nano-modified composite gelling material, comprising 60 parts of slag, 40 parts of construction waste powder, 4 parts of nano-material, 6 parts of alkali activator and appropriate amount of water, wherein the nano-material is nano-silicon dioxide, and the alkali activator is a composite activator of sodium hydroxide and sodium silicate. The preparation process thereof comprises the following steps: S1. Grind the slag and construction waste powder to a fineness of 45000cm² / g; S2, uniformly mixing the nanomaterials with slag and construction waste powder to form a matrix material; S3, adding a base activator to the matrix material; S4, adding water and stirring thoroughly to form a gelled slurry; S5. Cast the cementitious slurry into a shape, and perform carbonization treatment after curing for 28 days to obtain a composite cementitious material with a compressive strength of 65 MPa.

[0018] Example 2: A nano-modified composite gelling material, comprising 50 parts of slag, 50 parts of construction waste powder, 1 part of nano-material, 7 parts of alkali activator and appropriate amount of water, wherein the nano-material is nano-cellulose, and the alkali activator is a composite activator of sodium hydroxide and sodium silicate. The preparation process thereof comprises the following steps: S1. Grind the slag and construction waste powder to a fineness of 4000cm² / g; S2, uniformly mixing the nanomaterials with slag and construction waste powder to form a matrix material; S3, adding a base activator to the matrix material; S4, adding water and stirring thoroughly to form a gelled slurry; S5. Cast the cementitious slurry into a shape, and solidify it at room temperature after curing for 28 days to obtain a composite cementitious material with a compressive strength of 55 MPa.

[0019] Example 3: A nano-modified composite gelling material, comprising 70 parts of slag, 30 parts of construction waste powder, 5 parts of nano-material, 5 parts of alkali activator and appropriate amount of water, wherein the nano-material is nano-titanium dioxide, and the alkali activator is a composite activator of sodium hydroxide and sodium silicate. The preparation process thereof comprises the following steps: S1. Grind the slag and construction waste powder to a fineness of 5000cm² / g; S2, uniformly mixing the nanomaterials with slag and construction waste powder to form a matrix material; S3, adding a base activator to the matrix material; S4, adding water and stirring thoroughly to form a gelled slurry; S5, casting the gelling slurry, curing it for 28 days and then curing it at room temperature to obtain a composite gelling material with a compressive strength of 59 MPa. The cured material exhibits good photocatalytic performance and can continuously decompose organic pollutants on the surface under sunlight.

[0020] In summary, the nano-modified composite cementitious material of the present invention can be used to replace traditional cement materials to achieve low-carbon construction. The material has excellent crack resistance and durability, and is suitable for road paving. Due to its photocatalytic self-cleaning properties, the material is suitable for building exterior walls and other structures exposed outdoors.

[0021] The above are only implementation modes of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent schemes made using the contents of the present invention specification, directly or indirectly applied in other related technical fields, are also within the patent protection scope of the present invention.

Claims

1. A nano-modified composite gelling material, characterized in that: The invention comprises the following ingredients: slag, construction waste powder, nano material, alkali activator and water.

2. The nano-modified composite gelling material according to claim 1, characterized in that: In parts by weight, the slag is 50-70 parts, the construction waste powder is 30-50 parts, the nano material is 1-5 parts, and the alkali activator is 5-7 parts.

3. The nano-modified composite gelling material according to claim 1 or 2, characterized in that: The nano material is nano silicon dioxide or nano titanium dioxide or nano cellulose.

4. The nano-modified composite gelling material according to claim 1 or 2, characterized in that: The alkaline activator is at least one of sodium hydroxide and sodium silicate.

5. The nano-modified composite gelling material according to claim 1 or 2, characterized in that: The preparation process comprises the following steps: S1. Grind the slag and construction waste powder to a fineness of 4000-5000cm² / g; S2, uniformly mixing the nanomaterials with slag and construction waste powder to form a matrix material; S3, adding a base activator to the matrix material; S4. Add water and stir thoroughly to form a gelled slurry.

6. The nano-modified composite gelling material according to claim 5, characterized in that: The method further comprises S5, casting the gelling slurry into a shape, and curing or carbonizing the slurry at room temperature after curing.