Grouting material resistant to high salt and alkali environment and preparation method thereof

Abstract

The application discloses a grouting material resistant to high-salt-alkali environment and a preparation method thereof. The grouting material comprises the following components in parts by weight: modified gypsum slag cement 40-60 parts, modified aggregate 30-50 parts, polycarboxylic acid water reducing agent 1-3 parts, composite expansion agent 2-8 parts, functional additive 0.2-1 part and hybrid fiber 0.4-2 parts. The grouting material can effectively solve the problem of poor salt-alkali resistance of the existing grouting material.

Description

Technical Field

[0001] This invention belongs to the field of grouting material technology, specifically relating to a grouting material resistant to high salinity and alkali environments and its preparation method. Background Technology

[0002] Grouting materials are generally cement-based composite materials made by mixing granular materials as aggregates, such as quartz sand, manufactured sand, and steel grit, with cement and admixtures as binders, and functional additives such as high-efficiency water-reducing agents, defoamers, and anti-segregation agents in a certain mass ratio. Currently, the powder components of grouting materials are mainly cement and admixtures. On the one hand, cement consumption is high, and the "two grindings and one burning" process in cement production consumes a lot of energy and emits a large amount of CO2, resulting in high overall energy consumption and carbon emissions for grouting materials. On the other hand, ordinary silicate cement has poor resistance to sulfate attack. This is mainly because the hydration products of silicate cement are mainly calcium hydroxide, ettringite, and CSH gel. Under the attack of sulfate, calcium hydroxide will be converted into gypsum dihydrate, increasing in volume; calcium silicate will decompose into gypsum dihydrate, expanding in volume; and hydrated calcium aluminate will be converted into ettringite, also increasing in volume, generating greater internal stress and causing sample failure.

[0003] Ca(OH)2+H2SO4→CaSO4·2H2O (1)

[0004] 3CaO·2SiO2·3H2O +H2SO4→CaSO4·2H2O+2Si(OH)4 (2)

[0005] CaSO4+3CaO·Al2O3·6H2O+25H2O→3CaO·Al2O3·CaSO4·32H2O(3)

[0006] Simultaneously, the sulfuric acid erosion environment also contains carbon-sulfur-silicon-calcium stone erosion and damage. The ettringite formed by sulfuric acid erosion reacts with CSH and CO3. 2- Ca 2+ When reacted with excess water, it forms unbinding calcium carbonate silicate. Once this unbinding calcium carbonate silicate forms, the hardened silicate cement paste becomes muddy and loses its strength. Therefore, grouting materials prepared with conventional silicate cement are less effective for high-salt erosion projects, especially those with high-sulfate erosion. Summary of the Invention

[0007] To address the aforementioned shortcomings in the prior art, this invention provides a grouting material resistant to high salinity and alkali environments and its preparation method, which can effectively solve the problem of poor salinity and alkali resistance in existing grouting materials.

[0008] To achieve the above objectives, the technical solution adopted by the present invention to solve its technical problem is as follows:

[0009] A grouting material resistant to high salinity and alkali environments comprises the following components in parts by weight: 40-60 parts modified gypsum slag cement, 30-50 parts modified aggregate, 0.2-0.6 parts polycarboxylate superplasticizer, 2-10 parts composite expansion agent, and 0.2-8 parts mixed fiber.

[0010] Furthermore, the modified gypsum slag cement comprises the following components in parts by weight: 3-5 parts alkali component, 3-5 parts ultrafine glass powder, 0.05-0.2 parts nano calcium oxide, 10-20 parts calcined phosphogypsum, 0.5-1.5 parts modified mineral fiber, and 60-80 parts slag powder.

[0011] Furthermore, the alkali component includes at least one of calcium hydroxide and cement clinker, and the particle size of the ultrafine glass powder is 1000-2000 mesh.

[0012] Furthermore, the modified mineral fiber is prepared by the following method: fly ash fiber and basalt fiber are mixed at a mass ratio of 1:0.5-2, and then a 3-8% acetic acid solution is sprayed onto the mixed fiber and soaked for 1-3 hours. Then, the mixed fiber with acetic acid is dried at 40-50℃ to obtain the product.

[0013] Furthermore, the modified aggregate is prepared by the following method: coral sand particles with a particle size of 0.5-4.75 mm are placed in silicate cement slurry, stirred thoroughly and soaked for 2-3 hours, then filtered to remove the slurry, and the coral sand particles are dispersed, dried and hardened to obtain the final product.

[0014] The silicate cement slurry is made by mixing 42.5 silicate cement, fly ash microspheres, water-reducing agent and water in a mass ratio of 1:0.2-0.3:0.00015-0.0025:0.2-0.25.

[0015] Furthermore, the composite expanding agent is prepared by mixing bauxite minerals, calcium sulfoaluminate and calcium oxide in a mass ratio of 1:0.2-1:0.2-0.5, and the composite expanding agent has a mesh size of 300-600.

[0016] Furthermore, the hybrid fiber is composed of copper-plated steel fiber and negative Poisson's ratio fiber in a mass ratio of 1:1-10.

[0017] Furthermore, the negative Poisson's ratio fiber is made by drawing and stubling negative Poisson's ratio steel bars, with a single filament length of 3-15mm and a diameter of 100-1000μm; the copper-plated steel fiber has a length of 8-13mm and a diameter of 200-300μm.

[0018] The above-mentioned method for preparing grouting material resistant to high salinity and alkali environments includes the following steps:

[0019] (1) Mix modified gypsum slag cement, modified aggregate, polycarboxylate superplasticizer and composite expansion agent to obtain premix;

[0020] (2) Mix the premixed material, mixed fiber and water evenly to obtain the product.

[0021] The beneficial effects of this invention are as follows:

[0022] The grouting material prepared in this application, which is resistant to high salt and alkali environments, has good salt and alkali resistance, can avoid salt and alkali erosion, and improve its stability and durability. Specifically, the grouting material of this application uses modified gypsum slag cement as the main raw material. The main products of the hydration of modified gypsum slag cement are ettringite, CSH and gypsum. Moreover, gypsum slag cement contains a large number of sulfate ions, which inhibits the erosion of sulfate ions in the environment to a certain extent. Furthermore, there is almost no calcium hydroxide in the products, and it will not be converted into dihydrate gypsum, which makes the grouting material resistant to sulfate erosion.

[0023] The addition of ultrafine glass powder and nano-calcium oxide to modified gypsum slag cement not only provides high activity but also excellent filling effect, significantly improving the density of the modified gypsum slag cement matrix, enhancing its impermeability, reducing sulfate erosion, and thus improving its resistance to corrosion. Among the added modified mineral fibers, fly ash participates in the hydration and hardening of the grout, increasing the toughness and impact resistance of the hardened body; basalt fiber, a silicate fiber, has good compatibility with the grout system, and its multi-directional distribution within the grout system provides connection and support, improving the volume stability of the grout system, reducing later-stage cracking, decreasing bleeding and micropore formation, enhancing the impermeability of the grout, and further contributing to improved salt erosion resistance.

[0024] In this application, bauxite minerals and calcium sulfoaluminate are used as early expansion agents to promote the formation of early hydration product ettringite and shorten the setting and hardening time of the grouting material system; calcium oxide is used as a later expansion agent to promote the formation of hydrated calcium silicate and ensure stable strength in the later stage.

[0025] In this application, modified coral sand particles are used as aggregate components. Coral particles themselves have good salt and alkali resistance. Attaching salt and alkali resistant slurry to the surface of coral particles can greatly improve the surface density and compressive strength of coral sand particles, thereby improving the overall compressive strength of the grout.

[0026] This application employs a hybrid fiber system based on negative Poisson's ratio fibers. Negative Poisson's ratio fibers are a type of fiber made from a novel steel material that exhibits a negative Poisson's ratio effect (significantly reduced Poisson's ratio), has no yield plateau, and a strain value greater than 20%. It also possesses characteristics such as non-magnetism, high strength, high toughness, and high uniform elongation, enabling it to adapt to large deformations, with deformation values ​​reaching 25%-37%. Based on this, the hybrid fiber-based grouting material exhibits higher compressive strength and deformation resistance than traditional steel fiber grouting materials. Furthermore, it shows no necking phenomenon under bending or tensile deformation, and the elongation of the grouting material can reach 2-10%. Attached Figure Description

[0027] Figure 1 The diagram shows the salt and alkali resistance test process of the product tubes in Example 3, Comparative Example 1, and Comparative Example 2.

[0028] Figure 2 This is a test result diagram of the product tube in Example 3;

[0029] Figure 3 The image shows the test results of the product tube in Comparative Example 1;

[0030] Figure 4 This is a test result diagram of the product tube in Comparative Example 2. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments.

[0032] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0033] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0034] The features and performance of the present invention will be further described in detail below with reference to the embodiments and accompanying drawings.

[0035] Example 1

[0036] A grouting material resistant to high salinity and alkali environments comprises the following components in parts by weight: 40 parts modified gypsum slag cement, 30 parts modified aggregate, 0.2 parts polycarboxylate superplasticizer, 2 parts composite expansion agent with a particle size of 300 mesh, and 0.2 parts mixed fiber.

[0037] The modified gypsum slag cement comprises the following components by weight: 3 parts calcium hydroxide, 3 parts ultrafine glass powder with a particle size of 1000 mesh, 0.05 parts nano calcium oxide, 10 parts calcined phosphogypsum, 0.5 parts modified mineral fiber, and 60 parts slag powder.

[0038] Modified mineral fibers were prepared by the following method: fly ash fibers and basalt fibers were mixed at a mass ratio of 1:0.5, and then a 3% acetic acid solution was sprayed onto the mixed fibers. The fibers were soaked for 1.5 hours, and then the mixed fibers with acetic acid were dried at 45°C to obtain the product.

[0039] The modified aggregate was prepared by the following method: Coral sand particles with a particle size of 0.5 mm were placed in silicate cement slurry, stirred thoroughly, and soaked for 2 hours. Then, the grout was removed by filtration, and the coral sand particles were dispersed, dried, and hardened to obtain the modified aggregate. The salt and alkali resistant slurry was prepared by mixing 525 cement, calcium sulfoaluminate, silica fume, S95 mineral powder, expanding agent, quartz sand, defoamer, and water-reducing agent in a weight ratio of 1:0.02:0.1:0.1:0.05:1:0.1:1. The silicate cement slurry was prepared by mixing 42.5 silicate cement, fly ash microspheres, water-reducing agent, and water in a mass ratio of 1:0.2:0.00015:0.2.

[0040] The composite expanding agent is made by mixing bauxite minerals, calcium sulfoaluminate, and calcium oxide in a mass ratio of 1:0.2 to 1:0.2.

[0041] The hybrid fiber is composed of copper-plated steel fiber and negative Poisson's ratio fiber in a 1:1 mass ratio; the copper-plated steel fiber has a length of 8 mm and a diameter of 200 μm; the negative Poisson's ratio fiber is made by drawing negative Poisson's ratio steel bars, with a single filament length of 3 mm and a diameter of 400 μm.

[0042] The preparation method of the above-mentioned grouting material resistant to high salinity and alkali environments includes:

[0043] (1) Mix modified gypsum slag cement, modified aggregate, polycarboxylate superplasticizer and composite expansion agent to obtain premix;

[0044] (2) Mix the premix, mixed fibers and water evenly.

[0045] Example 2

[0046] A grouting material resistant to high salinity and alkali environments comprises the following components in parts by weight: 60 parts modified gypsum slag cement, 50 parts modified aggregate, 0.6 parts polycarboxylate superplasticizer, 10 parts composite expansion agent with a particle size of 600 mesh, and 8 parts mixed fiber.

[0047] The modified gypsum slag cement comprises the following components in parts by weight: 5 parts calcium hydroxide, 5 parts ultrafine glass powder with a particle size of 2000 mesh, 0.2 parts nano calcium oxide, 20 parts calcined phosphogypsum, 1.5 parts modified mineral fiber, and 80 parts slag powder.

[0048] Modified mineral fibers were prepared by the following method: fly ash fibers and basalt fibers were mixed at a mass ratio of 1:2, and then an acetic acid solution with a mass concentration of 8% was sprayed onto the mixed fibers and soaked for 2 hours. The mixed fibers with acetic acid were then dried at 40°C to obtain the product.

[0049] The modified aggregate was prepared by the following method: Coral sand particles with a particle size of 4.75 mm were placed in silicate cement slurry, stirred thoroughly, and soaked for 3 hours. Then, the grout was removed by filtration, and the coral sand particles were dispersed, dried, and hardened to obtain the modified aggregate. The salt and alkali resistant slurry was prepared by mixing 525 cement, calcium sulfoaluminate, silica fume, S95 mineral powder, expanding agent, quartz sand, defoamer, and water-reducing agent in a weight ratio of 1:0.02:0.1:0.1:0.05:1:0.1:1. The silicate cement slurry was prepared by mixing 42.5 silicate cement, fly ash microspheres, water-reducing agent, and water in a mass ratio of 1:0.3:0.0025:0.25.

[0050] The composite expanding agent is made by mixing bauxite minerals, calcium sulfoaluminate and calcium oxide in a mass ratio of 1:0.2-1:0.5;

[0051] The hybrid fiber is composed of copper-plated steel fiber and negative Poisson's ratio fiber in a mass ratio of 1:10; the copper-plated steel fiber has a length of 10 mm and a diameter of 250 μm; the negative Poisson's ratio fiber is made by cutting negative Poisson's ratio steel bars into short strands, with a single filament length of 15 mm and a diameter of 1000 μm.

[0052] The preparation method of the above-mentioned grouting material resistant to high salinity and alkali environments includes:

[0053] (1) Mix modified gypsum slag cement, modified aggregate, polycarboxylate superplasticizer and composite expansion agent to obtain premix;

[0054] (2) Mix the premix, mixed fibers and water evenly.

[0055] Example 3

[0056] A grouting material resistant to high salinity and alkali environments comprises the following components in parts by weight: 50 parts modified gypsum slag cement, 40 parts modified aggregate, 0.5 parts polycarboxylate superplasticizer, 6 parts composite expansion agent with a particle size of 500 mesh, and 4 parts mixed fiber.

[0057] The modified gypsum slag cement comprises the following components by weight: 4 parts calcium hydroxide, 4 parts ultrafine glass powder with a particle size of 1500 mesh, 0.15 parts nano calcium oxide, 15 parts calcined phosphogypsum, 1 part modified mineral fiber, and 70 parts slag powder.

[0058] Modified mineral fibers are prepared by the following method: fly ash fibers and basalt fibers are mixed at a mass ratio of 1:1, then a 6% acetic acid solution is sprayed onto the mixed fibers, and the fibers are soaked for 2 hours. The mixed fibers with acetic acid are then dried at 50°C to obtain the product.

[0059] The modified aggregate was prepared by the following method: Coral sand particles with a particle size of 3 mm were placed in silicate cement slurry, stirred thoroughly, and soaked for 2 hours. Then, the grout was removed by filtration, and the coral sand particles were dispersed, dried, and hardened to obtain the modified aggregate. The salt and alkali resistant slurry was prepared by mixing 525 cement, calcium sulfoaluminate, silica fume, S95 mineral powder, expanding agent, quartz sand, defoamer, and water-reducing agent in a weight ratio of 1:0.02:0.1:0.1:0.05:1:0.1:1. The silicate cement slurry was prepared by mixing 42.5 silicate cement, fly ash microspheres, water-reducing agent, and water in a mass ratio of 1:0.25:0.0002:0.2.

[0060] The composite expanding agent is made by mixing bauxite minerals, calcium sulfoaluminate and calcium oxide in a mass ratio of 1:0.2-1:0.4;

[0061] The hybrid fiber is composed of copper-plated steel fiber and negative Poisson's ratio fiber in a mass ratio of 1:5; the copper-plated steel fiber has a length of 13mm and a diameter of 300μm; the negative Poisson's ratio fiber is made by drawing negative Poisson's ratio steel bars, with a single filament length of 10mm and a diameter of 500μm.

[0062] The preparation method of the above-mentioned grouting material resistant to high salinity and alkali environments includes:

[0063] (1) Mix modified gypsum slag cement, modified aggregate, polycarboxylate superplasticizer and composite expansion agent to obtain premix;

[0064] (2) Mix the premix, mixed fibers and water evenly.

[0065] Comparative Example 1

[0066] Based on Example 3, the modified gypsum slag cement was replaced with ordinary gypsum slag cement.

[0067] Comparative Example 2

[0068] The experiment was conducted using ordinary silicate cement grout.

[0069] Experimental Example

[0070] Product tubes were prepared using the methods described in Example 3, Comparative Example 1, and Comparative Example 2. Salt and alkali resistance tests were conducted on different product tubes. The soaking solution used in the tests was prepared by mixing a 5% sodium sulfate solution and a pH 10 sodium hydroxide solution in a 1:1 volume ratio. The procedure was as follows: Figure 1 As shown.

[0071] Figure 1 The left image shows the product tube from Example 3, the middle image shows Comparative Example 1, and the right image shows the product tube from Comparative Example 2. After two years of salt and alkali corrosion resistance testing, the corrosion effect of the product tube from Example 3 is as follows: Figure 2 As shown; the corrosion effect of the product tube in Comparative Example 1 is as follows. Figure 3 As shown; the corrosion effect of the product tube in Comparative Example 2 is as follows. Figure 4 As shown, the tube produced by the method of this application has good salt and alkali resistance. After being stored in a salt and alkali environment for a long time, the edges and corners remain intact, and no obvious corrosion or surface peeling occurs. Figure 2 In contrast, the product tube prepared by the method in Comparative Example 1 had a thin layer of dissolved material floating in the solution on its surface, and the product tube showed slight corrosion. Figure 3 The corrosion effect of the product tube prepared by the method in Comparative Example 1 is as follows: Figure 4 As shown, the corrosion is quite severe, and the corrosion at the edges and corners is also quite obvious.

Claims

1. A grouting material resistant to high salinity and alkali environments, characterized in that, It is composed of the following components in parts by weight: 40-60 parts modified gypsum slag cement, 30-50 parts modified aggregate, 0.2-0.6 parts polycarboxylate superplasticizer, 2-10 parts composite expansion agent and 0.2-8 parts mixed fiber; The modified gypsum slag cement is composed of the following components in parts by weight: 3-5 parts alkali component, 3-5 parts ultrafine glass powder, 0.05-0.2 parts nano calcium oxide, 10-20 parts calcined phosphogypsum, 0.5-1.5 parts modified mineral fiber, and 60-80 parts slag powder. The modified mineral fiber is prepared by the following method: fly ash fiber and basalt fiber are mixed at a mass ratio of 1:0.5-2, then a 3-8% acetic acid solution is sprayed onto the mixed fiber for impregnation, and then the acetic acid-coated mixed fiber is dried at 40-50℃. The modified aggregate is prepared by the following method: coral sand particles with a particle size of 0.5-4.75 mm are placed in silicate cement slurry, stirred thoroughly and soaked for 2-3 hours, then filtered to remove the slurry, and the coral sand particles are dispersed, dried and hardened to obtain the modified aggregate. The silicate cement slurry is made by mixing 42.5 silicate cement, fly ash microspheres, water-reducing agent and water in a mass ratio of 1:0.2-0.3:0.00015-0.0025:0.2-0.

25. The composite expanding agent is prepared by mixing bauxite mineral, calcium sulfoaluminate and calcium oxide in a mass ratio of 1:0.2-1:0.2-0.5, and the composite expanding agent has a mesh size of 300-600. The hybrid fiber is composed of copper-plated steel fiber and negative Poisson's ratio fiber in a mass ratio of 1:1-10; the negative Poisson's ratio fiber is made by drawing and cutting negative Poisson's ratio steel bars, with a single filament length of 3-15mm, a diameter of 100-1000 μm, and a deformation value of 25%-37%; the copper-plated steel fiber has a length of 8-13mm and a diameter of 200-300 μm.

2. The grouting material resistant to high salinity and alkali environments as described in claim 1, characterized in that, The alkali component includes at least one of calcium hydroxide and cement clinker, and the ultrafine glass powder has a particle size of 1000-2000 mesh.

3. The method for preparing the grouting material resistant to high salinity and alkali environments according to any one of claims 1-2, characterized in that, Includes the following steps: (1) Mix modified gypsum slag cement, modified aggregate, polycarboxylate superplasticizer and composite expansion agent to obtain premix; (2) Mix the premixed material, mixed fiber and water evenly to obtain the product.

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