Portland cement with high corrosion resistance and preparation method thereof
By introducing specific raw materials and modifying silicate cement to generate a dense structure and physical barrier, the problem of insufficient corrosion resistance of traditional silicate cement in harsh environments is solved, and a highly efficient corrosion resistance effect is achieved.
Patent Information
- Application Number
- CN202510930215.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-07
- Publication Date
- 2025-10-14
AI Technical Summary
Traditional Portland cement has insufficient corrosion resistance in harsh environments and is prone to corrosion and peeling, affecting the safety and durability of buildings.
Using raw materials such as silica fume, metakaolin, slag powder, calcium nitrite, magnesium sulfate and silicone hydrophobic agent, a physical barrier to corrosive ions and moisture is formed by generating dense CSH gel, aluminosilicate gel and hydrophobic film, and combined with composite fibers to enhance corrosion resistance.
It significantly improves the corrosion resistance of silicate cement, reduces porosity and permeability of pore structure, enhances chemical corrosion resistance, improves early strength and fluidity, forms a multi-scale crack control network, and blocks erosion paths.
Smart Images
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of cement, more particularly, it relates to a high-erosion-resistant Portland cement and a preparation method thereof. BACKGROUND
[0002] As a commonly used basic material in construction engineering, the performance of Portland cement directly affects the quality and service life of buildings. Portland cement is not only widely used in the fields of buildings, bridges, tunnels and the like in daily life, but also occupies an important position in harsh environments such as oceans, chemical industry and saline-alkali land. However, the erosion resistance of traditional Portland cement is often insufficient, and problems such as corrosion and peeling often occur, which seriously affects the safety and durability of buildings.
[0003] In the related art, a large amount of mineral powder, fly ash, bottom slag and a small amount of silica fume are added to the cement clinker to improve the erosion resistance of the cement. However, the addition of a large amount of mineral composite materials in the cement-based material does not significantly improve the erosion resistance, and also causes negative effects such as low early strength and slow setting speed of the Portland cement. Therefore, there is an urgent need for a high-erosion-resistant Portland cement. SUMMARY
[0004] In order to improve the erosion resistance of Portland cement, the present application provides a high-erosion-resistant Portland cement and a preparation method thereof.
[0005] In a first aspect, the present application provides a high-erosion-resistant Portland cement, which adopts the following technical solution: A high-erosion-resistant Portland cement, which comprises the following raw materials by weight: Portland cement clinker 25-45 parts, gypsum 3-5 parts, silica fume 4-8 parts, metakaolin 3-5 parts, slag powder 15-30 parts, calcium nitrite 1.5-3 parts, magnesium sulfate 0.5-1.5 parts, and organosilicon hydrophobic agent 0.1-0.5 parts.
[0006] By adopting the above technical solution, the silica fume can fill the capillary pores, significantly reduce the porosity, promote secondary hydration, generate dense C-S-H gel, inhibit the migration of erosive ions, and improve the erosion resistance of the Portland cement. The high-activity Al2O3 and SiO2 of the metakaolin after high-temperature calcination rapidly consume Ca(OH)2, reduce the risk of acid erosion dissolution, and also generate alumosilicate gel to enhance the chemical corrosion resistance of the matrix. In addition, the silica fume and slag powder can compensate for the low early strength of the Portland cement caused by the addition of metakaolin.
[0007] The Ca 2+ stabilizes the C-S-H structure, promotes the hydration of C3S and C3A, forms a dense early C-S-H gel skeleton and AFt, rapidly reduces the initial permeability, delays the erosion reaction, and the Mg 2+ and The insoluble Mg(OH)2 precipitate is preferentially generated, the Mg(OH)2 precipitate is filled in the microstructure formed by the accelerated hydration of calcium nitrite, the pore structure is refined, the microstructure is more compact, a more effective physical barrier to the migration of erosive ions (Cl-, ) and water is formed, and the corrosion resistance of the Portland cement is improved. The organic silicon hydrophobic agent forms a hydrophobic film on the pore surface of the cement, reduces the capillary water absorption rate, blocks the transmission channel of Cl-, , and improves the corrosion resistance of the Portland cement.
[0008] As a preferred: a high corrosion resistance Portland cement, which comprises the following raw materials by weight: Portland cement clinker 30-40 parts, gypsum 3.5-4.5 parts, silica ash 5-7 parts, metakaolin 3.5-4.5 parts, slag powder 20-25 parts, calcium nitrite 2-2.5 parts, magnesium sulfate 0.8-1.2 parts, and organic silicon hydrophobic agent 0.2-0.4 parts.
[0009] The Portland cement of the present application selects Portland cement clinker 30-40 parts, gypsum 3.5-4.5 parts, silica ash 5-7 parts, metakaolin 3.5-4.5 parts, slag powder 20-25 parts, calcium nitrite 2-2.5 parts, magnesium sulfate 0.8-1.2 parts, and organic silicon hydrophobic agent 0.2-0.4 parts, and the performance of the Portland cement is predictable, and all has high corrosion resistance.
[0010] As a preferred: the weight ratio of the magnesium sulfate to the calcium nitrite is 1:(2-4).
[0011] By adopting the above scheme, the weight ratio of the magnesium sulfate to the calcium nitrite is adjusted, the activity excitation of Ca 2+ and the corrosion inhibition of Mg 2+ are balanced, the microstructure formed by the two in the cement is further optimized, and the corrosion resistance of the Portland cement is further improved.
[0012] As a preferred: the metakaolin is prepared by modification, specifically: S1, dissolving an amino silane coupling agent in anhydrous ethanol to obtain an amino silane coupling agent solution; S2, ball milling the dried metakaolin, adding to a hydrochloric acid solution with a concentration of 1-5 mol / L, stirring at 300-500 r / min at 60-80°C for 2-4 h, filtering, washing and drying, then adding to a sodium hydroxide solution with a concentration of 1-5 mol / L, stirring at 200-300 r / min at 60-80°C for 2-4 h, filtering, washing and drying, then mixing with the amino silane coupling agent solution, adding sodium hexametaphosphate, stirring at 60-80°C for 2-3 h, vacuum drying, crushing, sieving, and obtaining modified metakaolin.
[0013] The mass ratio of the amino silane coupling agent to anhydrous ethanol is 1: (4-6); the mass ratio of the metakaolin to hydrochloric acid solution is 1: (10-20); the mass ratio of the metakaolin to sodium hydroxide solution is 1: (0.5-0.7); and the sodium hexametaphosphate is 0.3%-0.5% of the mass of the metakaolin.
[0014] By using the above scheme, the amino silane coupling agent is coated on the surface of the metakaolin, which can compensate for the poor fluidity and weak early strength of the Portland cement after the addition of the metakaolin, improve the corrosion resistance of the Portland cement, and ensure the fluidity and strength of the Portland cement, and ensure the basic performance of the Portland cement.
[0015] In step S2, the metakaolin is first ball milled, then soaked in a hydrochloric acid solution to remove impurities, and then soaked in a sodium hydroxide solution to activate the surface, which is beneficial to the subsequent coating of the amino silane coupling agent on the surface of the metakaolin, making the coating more uniform, and thus further improving the effect of the metakaolin on improving the corrosion resistance of the Portland cement.
[0016] Preferably, the amino silane coupling agent is 2-4% of the mass of the metakaolin.
[0017] By using the above scheme, the amount of the amino silane coupling agent is adjusted to improve the uniformity of the amino silane coupling agent coating on the surface of the metakaolin, thereby improving the corrosion resistance of the Portland cement.
[0018] Preferably, the high corrosion-resistant Portland cement further comprises a composite fiber; the composite fiber is a composite of polypropylene fiber and steel fiber, and the weight ratio of the composite fiber to the metakaolin is 1: (10-20).
[0019] By using the above scheme, the addition of polypropylene fiber in the high corrosion-resistant Portland cement increases the tortuosity of the migration path of the erosion medium in the pores and microcracks, becomes a physical barrier to hinder the migration of ions and water, repels water molecules on the surface, reduces the adsorption and capillary action of water in the pore wall and crack wall, reduces the transmission power of water and dissolved ions, reduces the capillary absorption of water and the permeation rate of chloride ions, to improve the corrosion resistance of the Portland cement. Steel fiber provides stronger bridging force and more effectively limits the opening displacement of the crack, and PP fiber more effectively controls the load crack width to a lower level, providing a more excellent impermeable barrier.
[0020] The polypropylene fiber does not produce defects in the early stage, lays a good foundation for the steel fiber to play a role in the later stage, and at the same time makes the portland cement obtain low permeability and strong crack resistance, comprehensively improves the ability to resist various erosions, forms a multi-scale crack control network from micro to macro, and blocks the erosion path in all directions. The mass ratio of the polypropylene fiber and the steel fiber is controlled, the erosion path can be further blocked, and the erosion resistance of the portland cement is improved.
[0021] As preferred: the mass ratio of the polypropylene fiber and the steel fiber is 1:(5-10).
[0022] In a second aspect, the application provides a preparation method of the high-erosion-resistant portland cement, which is specifically realized by the following technical scheme: A preparation method of a high-erosion-resistant portland cement, comprising the following operation steps: The portland cement clinker, gypsum, silica ash, metakaolin and other raw materials are mixed after being ground separately to obtain the high-erosion-resistant portland cement.
[0023] In summary, the application includes at least one of the following beneficial technical effects: 1. The application controls the types and amounts of the raw materials of the portland cement, so that the chloride ion diffusion coefficient of the obtained portland cement at 28d is 0.40*10 -12 ~0.43*10 -12 m 2 / s, the seawater erosion resistance coefficient K 28 is 1.25-1.31, and the erosion resistance of the portland cement is improved.
[0024] 2. The application modifies the metakaolin in the raw materials of the portland cement and controls the amount of the amino silane coupling agent, so that the chloride ion diffusion coefficient of the portland cement at 28d is 0.29*10 -12 ~0.30*10 -12 m 2 / s, the seawater erosion resistance coefficient K 28 is 1.37-1.39, and the erosion resistance of the portland cement is further improved.
[0025] 3. The application adds composite fibers to the high-erosion-resistant portland cement in the raw materials of the portland cement and controls the mass ratio of the polypropylene fiber and the steel fiber in the composite fibers, so that the chloride ion diffusion coefficient at 28d is 0.21*10 -12 ~0.25*10 -12 m 2 / s, the seawater erosion resistance coefficient K 28 is 1.43-1.46, and the erosion resistance of the portland cement is further improved. DETAILED DESCRIPTION
[0026] The application will be further described in detail in connection with specific examples. The following raw materials in the application are commercially available, and are disclosed fully to make the source of the raw materials not be limited. Specifically, the portland cement clinker is low-alkali type, which is purchased from Xinglong County Fucheng Cement Co., Ltd.; the gypsum is desulfurization gypsum; the silica fume has a silica content of 80% and a particle size of 0.2 μm; the metakaolin has a silica content of 46% and a particle size of 1250 meshes; the slag powder has a particle size of 325 meshes; the calcium nitrite has an active substance content of 99%; the magnesium sulfate is industrial grade and has an active substance content of 99%; the organosilicon water repellent has a solid content of 50%; the amino silane coupling agent is model XH-2170; the sodium hexametaphosphate has an active substance content of 68%; the polypropylene fiber has a diameter of 2 mm and a fiber length of 300 mm; and the steel fiber has a diameter of 0.2 mm and a fiber length of 13 mm.
[0027] The following is a preparation example of the modified metakaolin: Preparation Example 1 The modified metakaolin of Preparation Example 1 is obtained by the following operation steps: S1, 10 g of the amino silane coupling agent is dissolved in 150 mL of anhydrous ethanol to obtain an amino silane coupling agent solution; S2, 1 kg of the dried metakaolin is ball milled and added to 15 L of a 3 mol / L hydrochloric acid solution, stirred at 70°C at a stirring rate of 400 r / min for 3 h, filtered, washed and dried, then added to 0.6 L of a 3 mol / L sodium hydroxide solution, stirred at 70°C at a stirring rate of 250 r / min for 3 h, filtered, washed and dried, mixed with the amino silane coupling agent solution, added with sodium hexametaphosphate, stirred at 70°C for 2.5 h, vacuum dried, crushed, sieved, and the modified metakaolin is obtained.
[0028] Preparation Examples 2-5 The modified metakaolin of Preparation Examples 2-5 is completely the same as the raw material types and preparation method of Preparation Example 1, and the difference is that the dosages of the amino silane coupling agent are different, specifically 20 g, 30 g, 40 g and 50 g, and the types and dosages of the other raw materials are the same as those of Preparation Example 1.
[0029] Example 1 The high-erosion-resistant portland cement of Example 1 is prepared by the following operation steps: The portland cement clinker, the gypsum, the silica fume, the metakaolin and the other raw materials are separately ground and mixed according to the dosages in Table 1 to obtain the high-erosion-resistant portland cement.
[0030] Examples 2-5 The high-erosion-resistant portland cement of Examples 2-5 is prepared by the same method and using the same raw materials as in Example 1, except that the amounts of the raw materials are different, as shown in Table 1.
[0031] Table 1 Amounts of raw materials for the high-erosion-resistant portland cement of Examples 1-5 (unit: kg) Examples 6-10 The high-erosion-resistant portland cement of Examples 6-10 is prepared by the same method as in Example 3, except that the metakaolin is replaced by the modified metakaolin prepared in Preparation Examples 1-5, and the amounts of the other raw materials are the same as in Example 3.
[0032] Examples 11-15 The high-erosion-resistant portland cement of Examples 11-15 is prepared by the same method as in Example 8, except that the high-erosion-resistant portland cement further comprises 0.27 kg of composite fibers, which are a mixture of polypropylene fibers and steel fibers, and the amounts of the polypropylene fibers and the steel fibers in Examples 11-15 are 0.05 kg and 0.22 kg, 0.04 kg and 0.023 kg, 0.03 kg and 0.24 kg, 0.025 kg and 0.245 kg, and 0.022 kg and 0.248 kg, respectively, and the amounts of the other raw materials are the same as in Example 8.
[0033] Comparative Example 1 The high-erosion-resistant portland cement of Comparative Example 1 is prepared by the same method as in Example 1, except that the calcium nitrite in the raw materials of the high-erosion-resistant portland cement is replaced by an equal amount of magnesium sulfate, and the amounts of the other raw materials are the same as in Example 1.
[0034] Comparative Example 2 The high-erosion-resistant portland cement of Comparative Example 2 is prepared by the same method as in Example 1, except that the magnesium sulfate in the raw materials of the high-erosion-resistant portland cement is replaced by an equal amount of calcium nitrite, and the amounts of the other raw materials are the same as in Example 1.
[0035] Comparative Example 3 The high-erosion-resistant portland cement of Comparative Example 3 is prepared by the same method as in Example 1, except that the metakaolin is not added to the raw materials of the high-erosion-resistant portland cement, and the amounts of the other raw materials are the same as in Example 1.
[0036] Performance testing The high-erosion-resistant portland cement obtained in each of Examples 1-15 and Comparative Examples 1-3 is tested for performance by using the following testing standards or methods, and the testing results are shown in Table 2.
[0037] Compressive strength: The compressive strength of portland cement at 3d and 28d was detected according to GB / T 17671-2021 standard.
[0038] Chloride ion diffusion coefficient: The chloride ion diffusion coefficient of portland cement at 28d was determined according to JC / T 1086-2008.
[0039] Marine erosion resistance coefficient: The marine erosion resistance coefficient K of portland cement was determined according to GB / T 749-2008. 28 .
[0040] Table 2 Performance detection results of different high-erosion-resistant portland cements It can be seen from the detection results in Table 2 that the 3d and 28d compressive strengths of the portland cement obtained by the application are up to 34.3MPa and 72.5MPa, respectively, and the portland cement has high strength; the chloride ion diffusion coefficient of the portland cement at 28d is as low as 0.21x10 -12 m 2 / s, and the marine erosion resistance coefficient K 28 is 1.46, which improves the erosion resistance of the portland cement.
[0041] It can be seen from the performance detection data of the portland cements in Examples 1-5 that the chloride ion diffusion coefficient of the portland cement at 28d in Examples 2-4 is 0.40x10 -12 -0.43x10 -12 m 2 / s, which is lower than that in Examples 1 and 5, and the marine erosion resistance coefficient K 28 is 1.25-1.31, which is higher than that in Examples 1 and 5, indicating that the weight ratio of magnesium sulfate to calcium nitrite in the raw materials of the portland cement is 1:(2-4), which is more appropriate, and improves the erosion resistance of the portland cement.
[0042] It can be seen from the performance detection data of the portland cements in Examples 6-10 that the chloride ion diffusion coefficient of the portland cement at 28d in Examples 7-9 is 0.29x10 -12 -0.30x10 -12 m 2 / s, which is lower than that in Examples 1 and 5, and the marine erosion resistance coefficient K 28 is 1.37-1.39, which is higher than that in Examples 1 and 5, indicating that the modification of metakaolin in the raw materials of the portland cement and the control of the amount of amino-based silane coupling agent can further improve the erosion resistance of the portland cement.
[0043] It can be seen from the performance detection data of the high-erosion-resistant portland cements in Examples 11-15 that the chloride ion diffusion coefficient of the portland cement at 28d in Examples 12-14 is 0.21x10-12 ~0.25x10 -12 m 2 / s, lower than that of Example 1 and Example 5, the anti-seawater erosion coefficient K 28 is 1.43-1.46, higher than that of Example 1 and Example 5, indicating that the addition of composite fibers in the silicate cement raw material, and the control of the mass ratio of polypropylene fibers and steel fibers in the composite fibers, improves the erosion resistance of the silicate cement.
[0044] It is found from the performance detection data of Example 1 and Comparative Examples 1-3 that the addition of calcium nitrite, magnesium sulfate, and organic silicon hydrophobic agent in the silicate cement raw material can improve the erosion resistance of the silicate cement to different degrees.
[0045] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the present specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.
Claims
1. A highly corrosion-resistant silicate cement, characterized in that: The invention comprises the following raw materials in parts by weight: 25-45 parts of Portland cement clinker, 3-5 parts of gypsum, 4-8 parts of silica fume, 3-5 parts of metakaolin, 15-30 parts of slag powder, 1.5-3 parts of calcium nitrite, 0.5-1.5 parts of magnesium sulfate and 0.1-0.5 parts of organic silicon water repellent.
2. The high corrosion-resistant silicate cement according to claim 1, characterized in that The invention comprises the following raw materials in parts by weight: 30-40 parts of Portland cement clinker, 3.5-4.5 parts of gypsum, 5-7 parts of silica fume, 3.5-4.5 parts of metakaolin, 20-25 parts of slag powder, 2-2.5 parts of calcium nitrite, 0.8-1.2 parts of magnesium sulfate and 0.2-0.4 parts of organic silicon water repellent.
3. The high corrosion-resistant silicate cement according to claim 1, characterized in that: The weight ratio of the magnesium sulfate to calcium nitrite is 1:(2-4).
4. The high corrosion-resistant silicate cement according to claim 1, characterized in that The metakaolin is prepared by modification, specifically: S1, dissolving an amino silane coupling agent in anhydrous ethanol to obtain an amino silane coupling agent solution; S2. Ball-mill the dried metakaolin, add it to a hydrochloric acid solution with a concentration of 1-5 mol / L, stir it at a stirring rate of 300-500 r / min at 60-80° C. for 2-4 h, filter, wash, and dry it, then add it to a sodium hydroxide solution with a concentration of 1-5 mol / L, stir it at a stirring rate of 200-300 r / min at 60-80° C. for 2-4 h, filter, wash, and dry it, then mix it with an amino silane coupling agent solution, add sodium hexametaphosphate, stir it at 60-80° C. for 2-3 h, vacuum dry it, crush it, and sieve it to obtain modified metakaolin.
5. The high corrosion-resistant silicate cement according to claim 4, characterized in that: The amino silane coupling agent accounts for 2-4% of the mass of the metakaolin.
6. The high corrosion-resistant silicate cement according to claim 1, characterized in that: The high corrosion-resistant silicate cement also includes composite fibers; the composite fibers are a composite of polypropylene fibers and steel fibers, and the weight ratio of the composite fibers to metakaolin is 1:(10-20).
7. The high corrosion-resistant silicate cement according to claim 6, characterized in that: The mass ratio of the polypropylene fiber to the steel fiber is 1:(5-10).
8. A method for preparing the highly corrosion-resistant Portland cement according to any one of claims 1 to 7, characterized in that: The following steps are included: Portland cement clinker, gypsum, silica fume, metakaolin and other raw materials are ground separately and then mixed to obtain high corrosion-resistant Portland cement.