Chloride ion erosion resistant composite cement mortar and preparation method thereof

Abstract

The invention relates to the field of cement mortar, and particularly discloses chloride ion corrosion resistant composite cement mortar and a preparation method of the chloride ion corrosion resistant composite cement mortar. A modifier of the high-activity metakaolin is prepared from at least one of 1-methyl-3 (4-vinyl benzyl) imidazole chloride salt, 1-methyl-3-(4-vinyl benzyl) pyrrole chloride salt and 1-methyl-3-vinyl iodized imidazole salt. The long-term strength of the cement-based material can be effectively improved, and the chloride ion erosion resistance can be greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of cement mortar, and more specifically, to a composite cement mortar resistant to chloride ion corrosion and a preparation method thereof. Background Art

[0002] The production process of cement emits a large amount of greenhouse gas CO2, accounting for about 5-10% of greenhouse gases emitted by human activities. The most common way to reduce the use of cement is to replace cement clinker with auxiliary cementitious materials, but traditional auxiliary cementitious materials may not be able to meet the demand for future usage. For cement systems with auxiliary cementitious materials, an important factor affecting their long-term service performance is durability, and durability issues include sulfate corrosion, chloride corrosion, freeze-thaw cycles, alkali-aggregate reaction, etc. Among the various exposure conditions and harmful substances that may be encountered during the service life, chloride salts are one of the most dangerous corrosive media, which will cause steel corrosion and thus reduce the durability of the structure. Therefore, the research and development of composite cement-based materials with high resistance to chloride ion corrosion is urgently needed.

[0003] It is very important to improve the durability of reinforced concrete structures. Here are some common methods:

[0004] 1. Add admixtures: Add admixtures such as mineral admixtures (fly ash, silica fume, slag, etc.)

[0005] 2. Increase the thickness of concrete cover: Increasing the thickness of concrete cover can provide better protection and reduce the exposure of steel bars to the external environment.

[0006] 3. Anti-corrosion coating: Apply anti-corrosion coating, such as epoxy coating or anti-corrosion paint, on the surface of steel bars to reduce the corrosion of steel bars.

[0007] In the selection of auxiliary cementitious materials, we use treated kaolin to replace cement, because my country has abundant kaolin resources, and after processing, it will produce volcanic ash activity and produce cementitious substances, so we need to modify kaolin to make it have volcanic ash activity. At present, most of the schemes for modifying kaolin are high-temperature modification, but there are many problems with high-temperature calcined kaolin. First, from an environmental perspective, high-temperature calcined kaolin will produce a series of combustion products and by-products. If these substances are released into the atmosphere in large quantities, they may cause certain harm to the environment. Secondly, from a safety perspective, high-temperature calcined kaolin will produce dust during processing. Long-term exposure to dust will cause harm to human health, especially to the respiratory system. In addition, there are risks of dangerous events such as explosions and fires during the calcination process. Finally, factors such as calcination temperature, time, and atmosphere may affect the performance and quality of the final product, so it is necessary to strictly control the calcination conditions to ensure the stability of product quality. Summary of the invention

[0008] The present application provides a composite cement mortar resistant to chloride ion corrosion and a preparation method thereof. High-activity metakaolin obtained by chemically modifying kaolin can interact well with other components after being added to a cement system, thereby effectively improving the later strength of the cement-based material and greatly enhancing the ability to resist chloride ion corrosion.

[0009] In a first aspect, the present application provides a composite cement mortar resistant to chloride ion corrosion, which adopts the following technical solution:

[0010] A composite cement mortar resistant to chloride ion corrosion, the raw materials comprising the following components by mass percentage:

[0011]

[0012] The high-activity metakaolin is prepared from raw materials including urea-kaolin and a modifier, and the mass ratio of the urea-kaolin to the modifier is 1:(4-7); or the high-activity metakaolin is prepared from raw materials including dimethyl sulfoxide-kaolin and a modifier, and the mass ratio of the dimethyl sulfoxide-kaolin and the modifier is 1:(4-7); the modifier includes at least one of 1-methyl-3 (4-vinylbenzyl) imidazole chloride, 1-methyl-3-(4-vinylbenzyl) pyrrole chloride, and 1-methyl-3-vinyl imidazole iodide.

[0013] By adopting the above technical solution, kaolin, as a new type of auxiliary cementitious material, whose main components are Al2O3 and SiO2, when added to cement-based materials, will affect the pores of cement slurry, resulting in pore refinement, increasing the density of the system, and thus improving the compressive strength of cement-based materials, significantly reducing the moisture transmission and harmful ion diffusion rate in cement-based materials, and improving the durability of cement-based materials.

[0014] The addition of calcium carbonate whiskers can improve the microstructure of cement-based materials. Due to its micro-aggregate filling effect and the promotion of CSH nucleation growth, the pore size distribution of the system can be optimized. During the cement hardening process, calcium carbonate whiskers can form a bridging effect, so that the internal cracks can be "repaired", thus making the microstructure more compact. In addition, calcium carbonate will react with C3A in the clinker to form semi-carbon hydrated calcium aluminate (C4AC 0.5 H 12 , Hc) and monocarbonate calcium aluminate hydrate (C4ACH 11 , Mc), such products can chemically bind chloride ions and reduce the content of free chloride ions in the pore solution. The newly generated carbon aluminate phase can also better fill the voids, reduce the porosity of cement-based materials, obtain a denser structure, and improve the durability of cement-based materials.

[0015] Using fly ash instead of cement can realize the resource utilization of industrial waste residues, and it also helps to reduce the heat release of cement hydration and cracking of cement concrete, thereby improving the mechanical properties and durability of cement concrete. When gypsum is present, the hydrated calcium aluminate generated by the active Al2O3 in the composite material will react with gypsum to generate calcium aluminate, thereby improving the density.

[0016] In addition, the high-activity metakaolin modified by the specific modifier of the present application can produce a good micro-aggregate effect when used in combination with fly ash, calcined coal gangue and calcium carbonate whiskers, effectively refine the pore size of cement-based materials, and improve the performance of cement-based materials. There is a synergistic effect between the high-activity metakaolin of the present application and fly ash, calcined coal gangue, and calcium carbonate whiskers, which can promote the formation of semi-carbon type hydrated calcium aluminate and mono-carbon type hydrated calcium aluminate, and is conducive to the chemical binding of chloride ions.

[0017] Therefore, when the specially modified high-activity kaolin of the present application is used in combination with fly ash, calcium carbonate whiskers, etc., the system's resistance to chloride ion corrosion can be improved on the basis of reducing the amount of cement clinker used, and at the same time, the amount of silicate cement clinker used can be reduced, saving costs, making the kaolin-fly ash-calcium carbonate whisker composite cementitious system more economical, and can also reduce carbon emissions from the cement industry.

[0018] Furthermore, the preparation method of 1-methyl-3 (4-vinylbenzyl) imidazole chloride comprises the following steps: 1-methylimidazole and 4-vinylbenzyl chloride are added to ethylene dichloride, wherein the molar ratio of 1-methylimidazole to 4-vinylbenzyl chloride is (4-6): (4-7); the mixture is refluxed at 50-80° C. for 10-20 hours, and excess 4-vinylbenzyl chloride is removed by washing to obtain 1-methyl-3 (4-vinylbenzyl) imidazole chloride.

[0019] Furthermore, the preparation method of 1-methyl-3-(4-vinylbenzyl)pyrrole chloride comprises the following steps: 1-methylpyrrolidine and 4-vinylbenzyl chloride are added to dichloroethane, wherein the molar ratio of 1-methylpyrrolidine to 4-vinylbenzyl chloride is (4-6):(5-7); the mixture is refluxed at 60-80° C. for 10-20 hours, and excess 4-vinylbenzyl chloride is removed by washing to obtain 1-methyl-3-(4-vinylbenzyl)pyrrole chloride.

[0020] Furthermore, the preparation method of the 1-methyl-3-vinyl imidazole iodide salt comprises the following steps: adding 1-vinylimidazole to dichloroethane, and then adding methyl iodide dropwise at room temperature, wherein the molar ratio of the 1-vinylimidazole to methyl iodide is (3-5): (5-10); stirring the mixture at room temperature for 20 to 30 hours, washing to remove excess methyl iodide, and obtaining the 1-methyl-3-vinyl imidazole iodide salt.

[0021] Furthermore, the high-activity metakaolin has D 50 The fly ash has a diameter between 1 and 30 μm. 50 The calcined coal gangue has a diameter of 1-30 μm. 50 The calcium carbonate whisker has a diameter between 1 and 30 μm. 50 Between 1-30μm.

[0022] Furthermore, the preparation method of the high-activity metakaolin comprises the following steps:

[0023] (1) dissolving the modifier in isopropanol; heating the mixture and stirring at 60-90° C.;

[0024] (2) Urea-kaolin or dimethyl sulfoxide-kaolin is added to the mixture, and the suspension is magnetically stirred at 80-100° C. for 10-20 hours under a nitrogen flow; the excess molten salt is removed by washing with isopropanol and centrifugation, and the obtained solid sample is dried at 50-70° C. for 10-20 hours, and finally ground to obtain high-activity metakaolin.

[0025] In a second aspect, the present application provides a method for preparing a composite cement mortar resistant to chloride ion corrosion, using the following technical solution:

[0026] A method for preparing a composite cement mortar resistant to chloride ion corrosion comprises the following steps: cement, high-activity metakaolin, calcined coal gangue, fly ash, calcium carbonate whisker and gypsum are uniformly mixed, and then water and sand are added and mixed uniformly to obtain cement mortar.

[0027] In summary, this application has the following beneficial effects:

[0028] 1. The high-activity metakaolin prepared in the present application, in addition to having the properties of metakaolin itself, can also produce a good micro-aggregate effect with fly ash, calcined coal gangue, calcium carbonate whiskers, etc., and can improve the system's resistance to chloride ion corrosion on the basis of reducing the amount of cement clinker. At the same time, it can reduce the amount of silicate cement clinker, saving costs, making the metakaolin-fly ash-calcium carbonate whisker composite cementitious system more economical, and can also reduce the carbon emissions of the cement industry.

[0029] 2. In the process of preparing high-activity metakaolin, the present application adopts a method of mixing a modifier and urea-kaolin or a modifier-dimethyl sulfoxide-kaolin and then adding it to a concrete system to obtain a modified high-activity metakaolin, which can not only achieve the same performance as high-temperature calcined modified kaolin, but also be more environmentally friendly. In addition, the use of the modifier of the present application, after urea and dimethyl sulfoxide (DMSO) are intercalated between the layers of kaolin to expand its interlayer structure, the modifier of the present application can enter the pre-intercalated kaolin, and compared with other modifiers, it has a higher ability to break the hydrogen-oxygen bonds inside kaolin, can destroy its interlayer structure, expand its specific surface area, and has volcanic ash activity. DETAILED DESCRIPTION

[0030] The present application is further described in detail below with reference to the embodiments.

[0031] The present application embodiment first provides a composite cement mortar resistant to chloride ion corrosion, wherein the raw materials include the following components by mass percentage:

[0032]

[0033] The high-activity metakaolin is prepared from raw materials including urea-kaolin and a modifier, wherein the mass ratio of urea-kaolin to the modifier is 1:(4-7). Alternatively, the high-activity metakaolin is prepared from raw materials including dimethyl sulfoxide-kaolin and a modifier, wherein the mass ratio of dimethyl sulfoxide-kaolin to the modifier is 1:(4-7).

[0034] The modifier includes at least one of 1-methyl-3 (4-vinylbenzyl) imidazolium chloride, 1-methyl-3- (4-vinylbenzyl) pyrrole chloride, and 1-methyl-3-vinyl imidazolium iodide.

[0035] The specific preparation method of the modifier used in this application is as follows:

[0036] Furthermore, the preparation method of 1-methyl-3 (4-vinylbenzyl) imidazole chloride (IL-1) comprises the following steps: 1-methylimidazole and 4-vinylbenzyl chloride are added to dichloroethane, and the molar ratio of 1-methylimidazole to 4-vinylbenzyl chloride is (4-6): (4-7); the mixture is refluxed at 50-80° C. for 10-20 hours, and the excess 4-vinylbenzyl chloride is removed by washing to obtain 1-methyl-3 (4-vinylbenzyl) imidazole chloride.

[0037] Furthermore, the preparation method of 1-methyl-3-(4-vinylbenzyl)pyrrole chloride (IL-2) comprises the following steps: 1-methylpyrrolidine and 4-vinylbenzyl chloride are added to dichloroethane, and the molar ratio of 1-methylpyrrolidine and 4-vinylbenzyl chloride is (4-6): (5-7); the mixture is refluxed at 60-80° C. for 10-20 hours, and the excess 4-vinylbenzyl chloride is removed by washing to obtain 1-methyl-3-(4-vinylbenzyl)pyrrole chloride.

[0038] Furthermore, the preparation method of 1-methyl-3-vinyl imidazole iodide (IL-3) comprises the following steps: adding 1-vinylimidazole to dichloroethane, and then adding iodomethane dropwise at room temperature, wherein the molar ratio of 1-vinylimidazole to iodomethane is (3-5): (5-10); stirring the mixture at room temperature for 20 to 30 hours, washing to remove excess iodomethane, and obtaining 1-methyl-3-vinyl imidazole iodide.

[0039] Furthermore, the preparation method of high-activity metakaolin comprises the following steps:

[0040] (1) dissolving the modifier in 50-150 mL of isopropanol; heating the mixture and stirring at 60-90° C.;

[0041] (2) Urea-kaolin or dimethyl sulfoxide-kaolin is added to the mixture, and the suspension is magnetically stirred at 80-100° C. for 10-20 hours under a nitrogen flow; the excess molten salt is removed by washing with isopropanol and centrifugation, and the obtained solid sample is dried at 50-70° C. for 10-20 hours, and finally ground to obtain high-activity metakaolin.

[0042] Further, the preparation method of urea-kaolin is as follows:

[0043] a) Prepare 200-500 ml of 5-9 mol / L urea solution;

[0044] b) mixing 1-5 g of kaolin with urea solution;

[0045] c) stirring at 20-50° C. for 30-50 hours;

[0046] d) obtaining a solid by centrifugation and drying it at 70-90° C. for 10-30 h to obtain urea-kaolin.

[0047] Specifically, the preparation method of urea-kaolin used in the examples of the present application is as follows:

[0048] a) Prepare 250 ml of 7 mol / L urea solution;

[0049] b) mixing 3 g of kaolin with the urea solution;

[0050] c) stirring at 20° C. for 48 h;

[0051] d) The solid was obtained by centrifugation and dried at 75° C. for 24 h to obtain urea-kaolin.

[0052] Furthermore, the preparation method of dimethyl sulfoxide-kaolin is as follows:

[0053] a) adding a mixture of 5-20 g kaolin, 70-150 ml dimethyl sulfoxide and 5-15 g distilled water into a three-necked flask equipped with a condenser and a mechanical stirrer;

[0054] b) stirring at a temperature of 70 to 90° C. for 60 to 80 hours;

[0055] c) After the reaction is completed, the suspension system is filtered and washed three times with ethanol to remove excess DMSO and distilled water; the washed kaolin is vacuum dried at 40-60° C. for 20-40 hours to obtain dimethyl sulfoxide-kaolin.

[0056] Specifically, the preparation method of dimethyl sulfoxide-kaolin used in this embodiment is as follows:

[0057] a) a mixture of 10 g kaolin, 100 ml dimethyl sulfoxide and 10 g distilled water was added into a three-necked flask equipped with a condenser and a mechanical stirrer;

[0058] b) stirring at 80° C. for 72 h;

[0059] c) After the reaction is completed, the suspension system is filtered and washed three times with ethanol to remove excess DMSO and distilled water; the washed kaolin is vacuum dried at 50° C. for 24 hours to obtain dimethyl sulfoxide-kaolin.

[0060] Furthermore, high activity metakaolin, its D 50 Between 1-30μm. Fly ash, its D 50 Between 1-30μm. Calcined coal gangue, its D 50 Between 1-30μm. Calcium carbonate whiskers, its D 50 Between 1-30μm.

[0061] The present embodiment also provides a method for preparing a composite cement mortar resistant to chloride ion corrosion, comprising the following steps: cement, high-activity metakaolin, calcined coal gangue, fly ash, calcium carbonate whisker and gypsum, after mixing evenly, add water and sand, mix evenly, and obtain cement mortar. Specifically, each component is put into a stirring pot, mechanically stirred, and after each component is evenly mixed, tap water is added to the stirring pot, and standard sand is added during the low-speed 30s stirring process, and rapid stirring, manual stirring and rapid stirring are performed successively to obtain a freshly mixed mortar for casting into a mold. Demolding obtains a cement-based material with high resistance to chloride ion corrosion. The amount of tap water and standard sand used may be determined according to the actual project conditions.

[0062] The following is an explanation through specific embodiments.

[0063] Embodiment 1:

[0064] (1) Dissolve 3 g of the modifier (IL-1) in 100 mL of isopropanol; heat the mixture and stir at 80°C;

[0065] (2) Urea-kaolin (modifier: urea-kaolin mass ratio is 4:1) was added to the mixture, and the suspension was magnetically stirred at 90°C for 16 h under a nitrogen flow; the excess molten salt was removed by washing with isopropanol and centrifugation, and the obtained solid sample was dried at 60°C for 16 h and finally ground to obtain high-activity metakaolin.

[0066] For the highly active metakaolin prepared above, cement, metakaolin, calcined coal gangue, fly ash, calcium carbonate whisker and gypsum with mass fractions of 50%, 24%, 3%, 3%, 15% and 5% respectively, with a total mass of 450g, are placed in a stirring pot and mechanically stirred for 60s. After the components are evenly mixed, 225g of tap water is added to the stirring pot, and 1350g of standard sand is added during the low-speed stirring process of 30s. The mortar is cast into a mold by rapid stirring for 30s, manual stirring for 60s, and rapid stirring for 60s. The cement-based material with high resistance to chloride ion corrosion is obtained by demolding.

[0067] Among them, the preparation method of 1-methyl-3 (4-vinylbenzyl) imidazole chloride (IL-1) of this embodiment comprises the following steps: 20mmol of 1-methylimidazole and 20mmol of 4-vinylbenzyl chloride are added to 20ml of dichloroethane, and the molar ratio of 1-methylimidazole to 4-vinylbenzyl chloride is 4:4; the mixture is refluxed at 60°C for 10 hours, and the excess 4-vinylbenzyl chloride is removed by washing with ether to obtain 1-methyl-3 (4-vinylbenzyl) imidazole chloride.

[0068] Embodiment 2:

[0069] (1) Dissolve 3 g of the modifier (IL-1) in 50 mL of isopropanol; heat the mixture and stir at 60°C;

[0070] (2) Dimethyl sulfoxide-kaolin (modifier: dimethyl sulfoxide-kaolin mass ratio is 5:1) is added to the mixture, and the suspension is magnetically stirred at 80°C for 10 h under a nitrogen flow; the excess molten salt is removed by washing with isopropanol and centrifugation, and the obtained solid sample is dried at 50°C for 10 h and finally ground to obtain high-activity metakaolin.

[0071] For the highly active metakaolin prepared above, cement, metakaolin, calcined coal gangue, fly ash, calcium carbonate whisker and gypsum with mass fractions of 50%, 18%, 6%, 6%, 15% and 5% respectively, with a total mass of 450g, are placed in a stirring pot and mechanically stirred for 60s. After the components are evenly mixed, 225g of tap water is added to the stirring pot, and 1350g of standard sand is added during the low-speed stirring process of 30s. The mortar is cast into a mold by successively performing rapid stirring for 30s, manual stirring for 60s, and rapid stirring for 60s. The mold is demolded to obtain a cement-based material with high resistance to chloride ion corrosion.

[0072] Among them, the preparation method of 1-methyl-3 (4-vinylbenzyl) imidazole chloride (IL-1) of this embodiment comprises the following steps: 30mmol of 1-methylimidazole and 35mmol of 4-vinylbenzyl chloride are added to 30ml of dichloroethane, and the molar ratio of 1-methylimidazole to 4-vinylbenzyl chloride is 6:7; the mixture is refluxed at 70°C for 20 hours, and the excess 4-vinylbenzyl chloride is removed by washing with ether to obtain 1-methyl-3 (4-vinylbenzyl) imidazole chloride.

[0073] Embodiment 3:

[0074] (1) Dissolve 3 g of the modifier (IL-2) in 150 mL of isopropanol; heat the mixture and stir at 90°C;

[0075] (2) Urea-kaolin (the mass ratio of modifier: urea-kaolin is 6:1) is added to the mixture, and the suspension is magnetically stirred at 100°C for 20 hours under a nitrogen flow; the excess molten salt is removed by washing with isopropanol and centrifugation, and the obtained solid sample is dried at 70°C for 20 hours and finally ground to obtain high-activity metakaolin.

[0076] For the highly active metakaolin prepared above, cement, metakaolin, calcined coal gangue, fly ash, calcium carbonate whisker and gypsum with mass fractions of 50%, 12%, 9%, 9%, 15% and 5% respectively, with a total mass of 450g, are placed in a stirring pot and mechanically stirred for 60s. After the components are evenly mixed, 225g of tap water is added to the stirring pot, and 1350g of standard sand is added during the low-speed stirring process of 30s. The mortar is cast into a mold by rapid stirring for 30s, manual stirring for 60s, and rapid stirring for 60s. The cement-based material with high resistance to chloride ion corrosion is obtained by demolding.

[0077] Furthermore, the preparation method of 1-methyl-3-(4-vinylbenzyl)pyrrole chloride (IL-2) in this embodiment comprises the following steps: adding 20 mmol of 1-methylpyrrolidine and 25 mmol of 4-vinylbenzyl chloride to 20 ml of dichloroethane, the molar ratio of 1-methylpyrrolidine to 4-vinylbenzyl chloride being 4:5; the mixture is refluxed at 60 ° C for 10 hours, and the excess 4-vinylbenzyl chloride is removed by washing with ether to obtain 1-methyl-3-(4-vinylbenzyl)pyrrole chloride.

[0078] Embodiment 4:

[0079] (1) Dissolve 3 g of the modifier (IL-3) in 75 mL of isopropanol; heat the mixture and stir at 85°C;

[0080] (2) Dimethyl sulfoxide-kaolin (the mass ratio of modifier: dimethyl sulfoxide-kaolin is 7:1) is added to the mixture, and the suspension is magnetically stirred at 85°C for 13 hours under a nitrogen flow; the excess molten salt is removed by washing with isopropanol and centrifugation, and the obtained solid sample is dried at 55°C for 13 hours and finally ground to obtain high-activity metakaolin.

[0081] For the highly active metakaolin prepared above, cement, metakaolin, calcined coal gangue, fly ash, calcium carbonate whisker and gypsum with mass fractions of 50%, 10%, 10%, 10%, 15% and 5% respectively, with a total mass of 450g, are placed in a stirring pot and mechanically stirred for 60s. After the components are evenly mixed, 225g of tap water is added to the stirring pot, and 1350g of standard sand is added during the low-speed stirring process of 30s. The mortar is cast into a mold by successively performing rapid stirring for 30s, manual stirring for 60s, and rapid stirring for 60s. The mold is demolded to obtain a cement-based material with high resistance to chloride ion corrosion.

[0082] The preparation method of 1-methyl-3-vinyl imidazole iodide (IL-3) in this embodiment comprises the following steps: adding 15 mmol of 1-vinylimidazole to 20 ml of dichloroethane, and then adding dropwise 25 mmol of methyl iodide at room temperature, wherein the molar ratio of 1-vinylimidazole to methyl iodide is 3:5; stirring the mixture at room temperature for 20 hours, washing with ether to remove excess methyl iodide, and obtaining 1-methyl-3-vinyl imidazole iodide.

[0083] Example 5

[0084] The difference between Example 5 and Example 3 is that the preparation method of 1-methyl-3-(4-vinylbenzyl)pyrrole chloride (IL-2) in this example comprises the following steps: 30 mmol of 1-methylpyrrolidine and 35 mmol of 4-vinylbenzyl chloride are added to 20 ml of dichloroethane, and the molar ratio of 1-methylpyrrolidine to 4-vinylbenzyl chloride is 6:7; the mixture is refluxed at 80° C. for 20 hours, and the excess 4-vinylbenzyl chloride is removed by washing with ether to obtain 1-methyl-3-(4-vinylbenzyl)pyrrole chloride.

[0085] Example 6

[0086] The difference between Example 6 and Example 4 is that the preparation method of 1-methyl-3-vinyl imidazole iodide (IL-3) in this example comprises the following steps: adding 25 mmol of 1-vinylimidazole to 30 ml of dichloroethane, and then adding 50 mmol of iodomethane dropwise at room temperature, the molar ratio of 1-vinylimidazole to iodomethane being 5:10; stirring the mixture at room temperature for 30 hours, washing with ether to remove excess iodomethane, and obtaining 1-methyl-3-vinyl imidazole iodide.

[0087] Comparative Example

[0088] Comparative Example 1

[0089] Put kaolin in a muffle furnace, set the heating rate of the muffle furnace so that the sample can be heated from room temperature to 800℃ within 150min, and calcine within this temperature range for 4h; after calcination, take out the sample and cool it quickly in the air, grind the sample to make it fine enough to meet the 80μm sieve residue of less than 1.0%. For the above-prepared active metakaolin, take 50%, 27%, 5%, 3%, 10% and 5% of cement, metakaolin, calcined coal gangue, fly ash, calcium carbonate whisker and gypsum, with a total mass of 450g, put it in a stirring pot, stir mechanically for 60s, after all the components are mixed evenly, add 225g of tap water to the stirring pot, add 1350g of standard sand during the low-speed stirring process for 30s, stir quickly for 30s, stir manually for 60s, stir quickly for 60s, and make a fresh mortar for casting into a mold. The demoulding results in a cement-based material having high resistance to chloride ion corrosion.

[0090] Comparative Example 2

[0091] Put kaolin in a muffle furnace, set the heating rate of the muffle furnace so that the sample can be heated from room temperature to 700℃ within 120min, and calcine within this temperature range for 4h; after calcination, take out the sample and cool it quickly in the air, grind the sample to make it fine enough to meet the 80μm sieve residue of less than 1.0%. For the above-prepared active metakaolin, take 50%, 27%, 3%, 15% and 5% of cement, metakaolin, fly ash, calcium carbonate whisker and gypsum, with a total mass of 450g, put it in a stirring pot, stir mechanically for 60s, after all the components are mixed evenly, add 225g of tap water to the stirring pot, add 1350g of standard sand during the low-speed stirring process for 30s, stir quickly for 30s, stir manually for 60s, stir quickly for 60s, and prepare the fresh mortar for casting into a mold. Demolding to obtain a cement-based material with high resistance to chloride ion corrosion.

[0092] Comparative Example 3

[0093] (1) Dissolve the modifier (IL-1) in 100 mL of isopropanol; heat the mixture and stir at 80°C;

[0094] (2) Urea-kaolin (the mass ratio of modifier: urea-kaolin is 8:1) was added to the mixture, and the suspension was magnetically stirred at 90°C for 16 hours under a nitrogen flow; the excess molten salt was removed by washing with isopropanol and centrifugation, and the obtained solid sample was dried at 60°C for 16 hours and finally ground to obtain high-activity metakaolin.

[0095] For the highly active metakaolin prepared above, cement, metakaolin, calcined coal gangue, fly ash, calcium carbonate whisker and gypsum with mass fractions of 50%, 24%, 3%, 3%, 15% and 5% respectively, with a total mass of 450g, are placed in a stirring pot and mechanically stirred for 60s. After the components are evenly mixed, 225g of tap water is added to the stirring pot, and 1350g of standard sand is added during the low-speed stirring process of 30s. The mortar is cast into a mold by rapid stirring for 30s, manual stirring for 60s, and rapid stirring for 60s. The cement-based material with high resistance to chloride ion corrosion is obtained by demolding.

[0096] Comparative Example 4

[0097] (1) Dissolve the modifier (IL-2) in 100 mL of isopropanol; heat the mixture and stir at 80°C;

[0098] (2) Urea-kaolin (the mass ratio of modifier: urea-kaolin is 3:1) was added to the mixture, and the suspension was magnetically stirred at 90°C for 16 h under a nitrogen flow; the excess molten salt was removed by washing with isopropanol and centrifugation, and the obtained solid sample was dried at 60°C for 16 h and finally ground to obtain high-activity metakaolin.

[0099] For the highly active metakaolin prepared above, cement, metakaolin, calcined coal gangue, fly ash, calcium carbonate whisker and gypsum with mass fractions of 50%, 24%, 3%, 3%, 15% and 5% respectively, with a total mass of 450g, are placed in a stirring pot and mechanically stirred for 60s. After the components are evenly mixed, 225g of tap water is added to the stirring pot, and 1350g of standard sand is added during the low-speed stirring process of 30s. The mortar is cast into a mold by rapid stirring for 30s, manual stirring for 60s, and rapid stirring for 60s. The cement-based material with high resistance to chloride ion corrosion is obtained by demolding.

[0100] Comparative Example 5

[0101] (1) dissolving the modifier 1-ethyl-3-methylimidazole in 100 mL of isopropanol; heating the mixture and stirring at 80° C.;

[0102] (2) Urea-kaolin (mass ratio of 1-ethyl-3-methylimidazole: urea-kaolin is 4:1) is added to the mixture, and the suspension is magnetically stirred at 90°C for 16 hours under a nitrogen flow; the excess molten salt is removed by washing with isopropanol and centrifugation, and the obtained solid sample is dried at 60°C for 16 hours and finally ground to obtain high-activity metakaolin.

[0103] For the highly active metakaolin prepared above, cement, metakaolin, calcined coal gangue, fly ash, calcium carbonate whisker and gypsum with mass fractions of 50%, 24%, 3%, 3%, 15% and 5% respectively, with a total mass of 450g, are placed in a stirring pot and mechanically stirred for 60s. After the components are evenly mixed, 225g of tap water is added to the stirring pot, and 1350g of standard sand is added during the low-speed stirring process of 30s. The mortar is cast into a mold by rapid stirring for 30s, manual stirring for 60s, and rapid stirring for 60s. The cement-based material with high resistance to chloride ion corrosion is obtained by demolding.

[0104] Comparative Example 6

[0105] (1) Dissolve the modifier 1-butyl-3-methylimidazole in 100 mL of isopropanol; heat the mixture and stir at 80° C.;

[0106] (2) Urea-kaolin (1-butyl-3-methylimidazole: urea-kaolin mass ratio of 4:1) was added to the mixture, and the suspension was magnetically stirred at 90°C for 16 h under a nitrogen flow; the excess molten salt was removed by washing with isopropanol and centrifugation, and the obtained solid sample was dried at 60°C for 16 h and finally ground to obtain highly active metakaolin.

[0107] For the highly active metakaolin prepared above, cement, metakaolin, calcined coal gangue, fly ash, calcium carbonate whisker and gypsum with mass fractions of 50%, 24%, 3%, 3%, 15% and 5% respectively, with a total mass of 450g, are placed in a stirring pot and mechanically stirred for 60s. After the components are evenly mixed, 225g of tap water is added to the stirring pot, and 1350g of standard sand is added during the low-speed stirring process of 30s. The mortar is cast into a mold by rapid stirring for 30s, manual stirring for 60s, and rapid stirring for 60s. The cement-based material with high resistance to chloride ion corrosion is obtained by demolding.

[0108] Comparative Example 7

[0109] (1) Dissolve the modifier (IL-3) in 100 mL of isopropanol; heat the mixture and stir at 50°C;

[0110] (2) Urea-kaolin (modifier: urea-kaolin mass ratio is 4:1) was added to the mixture, and the suspension was magnetically stirred at 70°C for 16 h under a nitrogen flow; the excess molten salt was removed by washing with isopropanol and centrifugation, and the obtained solid sample was dried at 60°C for 16 h and finally ground to obtain high-activity metakaolin.

[0111] For the highly active metakaolin prepared above, cement, metakaolin, calcined coal gangue, fly ash, calcium carbonate whisker and gypsum with mass fractions of 50%, 24%, 3%, 3%, 15% and 5% respectively, with a total mass of 450g, are placed in a stirring pot and mechanically stirred for 60s. After the components are evenly mixed, 225g of tap water is added to the stirring pot, and 1350g of standard sand is added during the low-speed stirring process of 30s. The mortar is cast into a mold by rapid stirring for 30s, manual stirring for 60s, and rapid stirring for 60s. The cement-based material with high resistance to chloride ion corrosion is obtained by demolding.

[0112] Comparative Example 8

[0113] (1) Dissolve the modifier (IL-2) in 100 mL of isopropanol; heat the mixture and stir at 80°C;

[0114] (2) Urea-kaolin (modifier: urea-kaolin mass ratio is 4:1) was added to the mixture, and the suspension was magnetically stirred at 90°C for 16 h under a nitrogen flow; the excess molten salt was removed by washing with isopropanol and centrifugation, and the obtained solid sample was dried at 60°C for 16 h and finally ground to obtain high-activity metakaolin.

[0115] For the high-activity metakaolin prepared above, various materials D 50 The particle size is 40-50 μm, and the cement, metakaolin, calcined coal gangue, fly ash, calcium carbonate whisker and gypsum with mass fractions of 50%, 24%, 3%, 3%, 15% and 5% respectively, with a total mass of 450 g, are placed in a stirring pot and mechanically stirred for 60 seconds. After the components are evenly mixed, 225 g of tap water is added to the stirring pot, and 1350 g of standard sand is added during the low-speed stirring process for 30 seconds, and rapid stirring for 30 seconds, manual stirring for 60 seconds, and rapid stirring for 60 seconds are performed successively to prepare a freshly mixed mortar for casting into a mold. The mold is demolded to obtain a cement-based material with high resistance to chloride ion corrosion.

[0116] Comparative Example 9

[0117] (1) Dissolve the modifier (IL-2) in 50 mL of isopropanol; heat the mixture and stir at 60°C;

[0118] (2) Urea-kaolin (modifier: urea-kaolin mass ratio is 4:1) was added to the mixture, and the suspension was magnetically stirred at 80°C for 16 h under a nitrogen flow; the excess molten salt was removed by washing with isopropanol and centrifugation, and the obtained solid sample was dried at 50°C for 10 h and finally ground to obtain high-activity metakaolin.

[0119] For the highly active metakaolin prepared above, cement, metakaolin, calcined coal gangue, fly ash, calcium carbonate whisker and gypsum with mass fractions of 40%, 3%, 22%, 21%, 6% and 8% respectively were taken, with a total mass of 450g, placed in a stirring pot, mechanically stirred for 60s, and after the components were evenly mixed, 225g of tap water was added to the stirring pot, and 1350g of standard sand was added during the low-speed stirring process of 30s, and rapid stirring for 30s, manual stirring for 60s, and rapid stirring for 60s were performed successively to obtain a freshly mixed mortar for casting into a mold. The mold was demolded to obtain a cement-based material with high resistance to chloride ion corrosion.

[0120] Blank group

[0121] Take 450g of cement, put it in a mixing pot, stir mechanically for 60s, and after all components are evenly mixed, add 225g of tap water to the mixing pot, add 1350g of standard sand during the low-speed stirring for 30s, and then stir quickly for 30s, manually stir for 60s, and stir quickly for 60s to prepare the freshly mixed mortar for casting into a mold. Demolding obtains ordinary cement-based materials.

[0122] Performance testing:

[0123] The cement-based materials prepared in the examples, comparative examples and blank groups were cured in a curing room (temperature 21° C., relative humidity 95%) for 28 days and 90 days before being tested for compressive strength (GB / T 50107-2010) and resistance to chloride ion penetration (RCM). The test results are shown in Table 1.

[0124] Table 1 Mortar performance test results

[0125]

[0126] According to the comparison of the test results of the embodiment and the test results of comparative examples 1-2, it can be seen that the high-activity metakaolin obtained by chemically modifying kaolin in the present application can interact well with the other components after adding it to the cement system, effectively improving the later strength of the cement-based material and greatly improving the resistance to chloride ion corrosion; and its performance is equivalent to that of kaolin modified by high-temperature calcination, and is even better than that of kaolin modified by high-temperature calcination, which can effectively save energy.

[0127] Analysis of the performance of Comparative Examples 3-6 revealed that the use of modifiers would affect the performance of high-activity metakaolin, and thus affect the performance of cement. Comparative Examples 3 and 4 reflected that too much or too little high-activity metakaolin would have adverse effects, because too much or too little high-activity metakaolin would affect the micro-aggregate effect of the remaining components. In addition, observation of the performance of Comparative Examples 5 and 6 revealed that the type of modifier would affect the material properties. In comparison, the 1-methyl-3 (4-vinylbenzyl) imidazole chloride, 1-methyl-3- (4-vinylbenzyl) pyrrole chloride, and 1-methyl-3-vinyl imidazole iodide used in the present application as modifiers can more effectively improve the performance of the material.

[0128] According to the performance test of Comparative Example 7, it can be seen that in the preparation process of high-activity metakaolin, the control of relevant temperature is also very important, otherwise it will have a certain impact on the material performance. According to the test results of Comparative Examples 8-9, it can be seen that the particle size of the raw materials will affect the performance of the final cement, and the amount of each component of the cement system will also affect the performance of the cement, because these factors will affect the interaction between the components, and then affect the performance of the cement.

[0129] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A composite cement mortar resistant to chloride ion corrosion, characterized in that: The raw materials include the following components by mass percentage: Wherein, the high-activity metakaolin is made from raw materials including urea-kaolin and a modifier, and the mass ratio of the urea-kaolin to the modifier is 1:(4-7); or the high-activity metakaolin is made from raw materials including dimethyl sulfoxide-kaolin and a modifier, and the mass ratio of the dimethyl sulfoxide-kaolin to the modifier is 1:(4-7); The modifier includes at least one of 1-methyl-3 (4-vinylbenzyl) imidazolium chloride, 1-methyl-3- (4-vinylbenzyl) pyrrole chloride, and 1-methyl-3-vinyl imidazolium iodide.

2. The composite cement mortar resistant to chloride ion corrosion according to claim 1, characterized in that: The preparation method of 1-methyl-3 (4-vinylbenzyl) imidazole chloride comprises the following steps: 1-methylimidazole and 4-vinylbenzyl chloride are added into ethylene dichloride, wherein the molar ratio of 1-methylimidazole to 4-vinylbenzyl chloride is (4-6): (4-7); the mixture is refluxed at 50-80° C. for 10-20 hours, and excess 4-vinylbenzyl chloride is removed by washing to obtain 1-methyl-3 (4-vinylbenzyl) imidazole chloride.

3. The composite cement mortar resistant to chloride ion corrosion according to claim 1, characterized in that: The preparation method of 1-methyl-3-(4-vinylbenzyl)pyrrole chloride comprises the following steps: 1-methylpyrrolidine and 4-vinylbenzyl chloride are added into dichloroethane, wherein the molar ratio of 1-methylpyrrolidine to 4-vinylbenzyl chloride is (4-6):(5-7); the mixture is refluxed at 60-80° C. for 10-20 hours, and excess 4-vinylbenzyl chloride is removed by washing to obtain 1-methyl-3-(4-vinylbenzyl)pyrrole chloride.

4. The composite cement mortar resistant to chloride ion corrosion according to claim 1, characterized in that: The preparation method of the 1-methyl-3-vinyl imidazole iodide salt comprises the following steps: adding 1-vinylimidazole into dichloroethane, then adding methyl iodide dropwise at room temperature, wherein the molar ratio of the 1-vinylimidazole to methyl iodide is (3-5):(5-10); stirring the mixture at room temperature for 20 to 30 hours, washing to remove excess methyl iodide, and obtaining the 1-methyl-3-vinyl imidazole iodide salt.

5. The composite cement mortar resistant to chloride ion corrosion according to claim 1, characterized in that: The highly active metakaolin, D 50 Between 1-30μm.

6. The composite cement mortar resistant to chloride ion corrosion according to claim 1, characterized in that: The fly ash, D 50 Between 1-30μm.

7. The composite cement mortar resistant to chloride ion corrosion according to claim 1, characterized in that: The calcined coal gangue, wherein D 50 Between 1-30μm.

8. The composite cement mortar resistant to chloride ion corrosion according to claim 1, characterized in that: The calcium carbonate whisker, D 50 Between 1-30μm.

9. The composite cement mortar resistant to chloride ion corrosion according to claim 1, characterized in that: The preparation method of the high-activity metakaolin comprises the following steps: (1) dissolving the modifier in isopropanol; heating the mixture and stirring at 60-90° C.; (2) Urea-kaolin or dimethyl sulfoxide-kaolin is added to the mixture, and the suspension is magnetically stirred at 80-100° C. for 10-20 hours under a nitrogen flow; the excess molten salt is removed by washing with isopropanol and centrifugation, and the obtained solid sample is dried at 50-70° C. for 10-20 hours, and finally ground to obtain high-activity metakaolin.

10. A method for preparing a composite cement mortar resistant to chloride ion corrosion according to any one of claims 1 to 8, characterized in that: The following steps are involved: Cement, high-activity metakaolin, calcined coal gangue, fly ash, calcium carbonate whisker and gypsum are mixed evenly, and then water and sand are added and mixed evenly to obtain cement mortar.

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