An anti-permeation low-shrinkage inorganic coating and a preparation method thereof

Abstract

The application discloses an anti-permeation low-shrinkage inorganic coating and a preparation method thereof. The anti-permeation low-shrinkage inorganic coating comprises cement material 40-60 parts by mass, active mixed material 15-30 parts by mass, gypsum 5-15 parts by mass, talcum powder 5-15 parts by mass, glycerin stearate 0-2 parts by mass and additive 4.7-6.7 parts by mass. The application selects green inorganic material, combines the characteristics of slow hydration of low-heat Portland cement, micro-expansion of high-magnesium low-heat Portland cement and micro-expansion of ettringite-like product formed between gypsum and cement hydration product, uses micro-expansion to relieve the shrinkage problem of the material, makes the material form a dense structure, and makes the material have the hydrophobic anti-permeation characteristics through the saponification reaction of glycerin stearate under alkaline conditions.

Description

Technical Field

[0001] This invention relates to the field of inorganic non-metallic materials technology, specifically to an impermeable, low-shrinkage inorganic coating and its preparation method. Background Technology

[0002] Cement concrete is the most widely used building material, making reinforced concrete structures the main structure of most buildings. It is entirely possible for reinforced concrete structures to meet national standards for service life, or even longer, according to design requirements. However, building structure leakage problems are now commonplace, and water erosion seriously affects building durability. To solve the problem of building leakage, in addition to achieving waterproofing through a dense structure, using waterproof coatings is also an effective method.

[0003] Rigid waterproof coatings have advantages over flexible waterproof coatings in that they are low in cost, contain no toxic or harmful substances, are easy to apply, and have good durability. However, rigid waterproof coatings also have certain drawbacks. They lack flexibility and are very sensitive to structural deformation caused by temperature and uneven settlement, making them prone to problems such as leakage and shrinkage cracks. Summary of the Invention

[0004] To overcome the above-mentioned technical defects and deficiencies, this invention provides an anti-permeability and low-shrinkage inorganic coating and its preparation method. The anti-permeability and low-shrinkage inorganic coating selects green inorganic materials and combines the characteristics of slow hydration of low-heat silicate cement, micro-expansion of high-magnesium low-heat silicate cement, and micro-expansion of ettringite-like products formed between gypsum and cement hydration products. The micro-expansion alleviates the shrinkage problem of the material, enabling it to form a dense structure. Furthermore, through the saponification reaction of glyceryl stearate under alkaline conditions, it acquires hydrophobic and anti-permeability properties.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] This invention discloses an impermeable, low-shrinkage inorganic coating, comprising the following raw materials in parts by weight:

[0007]

[0008]

[0009] In some embodiments of the present invention, the cement material comprises the following components by mass percentage: 20-35 wt% low-heat silicate cement, 30-50 wt% high-magnesium low-heat silicate cement, and 20-43 wt% rapid-hardening sulfoaluminate cement.

[0010] In some embodiments of the present invention, the mineral composition of the low-heat silicate cement is: 20-35 wt% C3S, 40-60 wt% C2S, 2-7% C3A, and 10-20% C4AF; the mineral composition of the high-magnesium low-heat silicate cement is: 20-35 wt% C3S, 35-60 wt% C2S, 1-8 wt% C3A, and 10-25 wt% C4AF, with an MgO content of 3-8 wt%; and the mineral composition of the rapid-hardening sulfoaluminate cement is: 50-70 wt% C4A3S, 10-35 wt% C2S, and 3-8 wt% C4AF.

[0011] In some embodiments of the present invention, the active mixed material is at least one of silica fume, fly ash, and blast furnace slag powder.

[0012] In some embodiments of the present invention, the gypsum is industrial solid waste phosphogypsum with a specific surface area of ​​500–700 m². 2 / kg

[0013] In some embodiments of the present invention, the talc powder is industrial-grade talc powder with a fineness of 3000 mesh.

[0014] In some embodiments of the present invention, the glyceryl stearate is glyceryl monostearate.

[0015] In some embodiments of the present invention, the additive is at least one of sodium silicate, defoamer, water-reducing agent, lithium carbonate, hydroxypropyl methylcellulose, and redispersible latex powder.

[0016] In some embodiments of the present invention, the hydroxypropyl methylcellulose is hydroxypropyl methylcellulose with a viscosity of 50,000.

[0017] This invention also discloses a method for preparing an anti-seepage, low-shrinkage inorganic coating, comprising the following steps:

[0018] S1. After uniformly mixing cementitious materials, active admixtures, gypsum, talc powder and glyceryl stearate, the mixture is ball-milled to obtain powder. Preferably, the ball milling speed is 200-400 r / s, the ball milling time is 10-40 min, and the powder particle size is 5-20 μm.

[0019] S2. Stir the powder and additives obtained in S1 at low speed for 60 seconds, add water and continue stirring at low speed for 30 seconds, and finally stir at high speed for 60 seconds to obtain a mixed slurry. The mass ratio of the powder to water is 1:0.25.

[0020] S3. Pour the mixed slurry into the mold, vibrate to form, cure, and demold to obtain the seepage-proof, low-shrinkage inorganic coating.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. This invention mainly uses low-heat silicate cement and high-magnesium low-heat silicate cement. Low-heat silicate cement has the characteristics of low shrinkage and low heat of hydration. Low heat of hydration can alleviate coating cracking. High-magnesium low-heat silicate cement has a micro-expansion effect. The hydrated alum-like products generated by adding gypsum also have a micro-expansion effect, effectively avoiding the problem of large shrinkage of coating.

[0023] 2. This invention selects glyceryl stearate, which has oleophilic properties, as a hydrophobic agent. By grinding the cementitious material (cement material) together with glyceryl stearate, the surface of the cementitious material particles is uniformly coated with glyceryl stearate. Under alkaline conditions, glyceryl stearate hydrates into stearate salt and glycerol, forming a hydrophobic film to achieve a seepage prevention effect. Talc powder has a certain degree of hydrophobicity. The active mixed material and talc powder can fill the capillaries inside the structure, reduce the porosity, and make the coating form a denser structure, further improving the seepage prevention performance.

[0024] 3. The sodium silicate in the additive of this invention is a crystalline additive, which can prevent moisture and has a certain degree of hydrophobicity. Sodium silicate can combine with calcium hydroxide to form insoluble calcium silicate, which fills the gaps. The incorporation of sodium silicate not only improves the anti-seepage performance of the coating, but also plays a positive role in activating the activity of the active mixed materials. Detailed Implementation

[0025] 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. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0026] In this embodiment of the invention, the mineral composition of low-heat silicate cement is: 20-35 wt% C3S, 40-60 wt% C2S, 2-7% C3A, and 10-20% C4AF; the mineral composition of high-magnesium low-heat silicate cement is: 20-35 wt% C3S, 35-60 wt% C2S, 1-8 wt% C3A, and 10-25 wt% C4AF, with an MgO content of 3-8 wt%; and the mineral composition of rapid-hardening sulfoaluminate cement is: 50-70 wt% C4A3S, 10-35 wt% C2S, and 3-8 wt% C4AF.

[0027] In this embodiment of the invention, the active mixing material is at least one of silica fume, fly ash, and blast furnace slag powder.

[0028] In this embodiment of the invention, the gypsum is industrial solid waste phosphogypsum with a specific surface area of ​​500–700 m². 2 / kg

[0029] In this embodiment of the invention, the talc powder is industrial grade talc powder with a fineness of 3000 mesh.

[0030] In this embodiment of the invention, glyceryl stearate is glyceryl monostearate.

[0031] In this embodiment of the invention, the additive is at least one of sodium silicate, defoamer, water-reducing agent, lithium carbonate, hydroxypropyl methylcellulose, and redispersible latex powder.

[0032] In this embodiment of the invention, the hydroxypropyl methylcellulose is hydroxypropyl methylcellulose with a viscosity of 50,000.

[0033] In this embodiment of the invention, the preparation method of the anti-seepage and low-shrinkage inorganic coating includes the following steps:

[0034] S1. After mixing cement materials, active admixtures, gypsum, talc powder and glyceryl stearate evenly, put them into a ball mill for ball milling. The ball milling speed is 200-400 r / s and the ball milling time is 10-40 min to obtain powder with a particle size of 5-20 μm.

[0035] S2. Stir the powder and additives obtained in S1 at low speed for 60 seconds, add water and continue stirring at low speed for 30 seconds, and finally stir at high speed for 60 seconds to obtain a mixed slurry. The mass ratio of the powder to water is 1:0.25.

[0036] S3. Pour the mixed slurry into the mold, vibrate to form, cure, and demold to obtain the seepage-proof, low-shrinkage inorganic coating.

[0037] Example 1

[0038] As a preferred embodiment of the present invention, the raw material composition of the anti-seepage low-shrinkage inorganic coating disclosed in this embodiment is shown in Table 1.

[0039] Table 1. Raw material composition of the seepage-proof, low-shrinkage inorganic coating in Example 1.

[0040]

[0041] In this embodiment, the cement material includes the following components by mass percentage: 30 wt% low-heat silicate cement, 45 wt% high-magnesium low-heat silicate cement, and 25 wt% rapid-hardening sulfoaluminate cement.

[0042] According to the mass fractions of each raw material in Table 1, the preparation method described above was used to obtain the anti-seepage, low-shrinkage inorganic coating #1.

[0043] Example 2

[0044] As a preferred embodiment of the present invention, the raw material composition of the anti-seepage low-shrinkage inorganic coating disclosed in this embodiment is shown in Table 2.

[0045] Table 2. Raw material composition of the seepage-proof, low-shrinkage inorganic coating in Example 2.

[0046]

[0047] In this embodiment, the cement material includes the following components by mass percentage: 35 wt% low-heat silicate cement, 45 wt% high-magnesium low-heat silicate cement, and 20 wt% rapid-hardening sulfoaluminate cement.

[0048] According to the mass fractions of each raw material in Table 2, the preparation method described above was used to obtain the anti-seepage, low-shrinkage inorganic coating #2.

[0049] Example 3

[0050] As a preferred embodiment of the present invention, the raw material composition of the anti-seepage low-shrinkage inorganic coating disclosed in this embodiment is shown in Table 3.

[0051] Table 3. Raw material composition of the seepage-proof, low-shrinkage inorganic coating in Example 3.

[0052]

[0053] In this embodiment, the cement material includes the following components by mass percentage: 20 wt% low-heat silicate cement, 50 wt% high-magnesium low-heat silicate cement, and 30 wt% rapid-hardening sulfoaluminate cement.

[0054] According to the mass fractions of each raw material in Table 3, the preparation method described above was used to obtain the anti-seepage, low-shrinkage inorganic coating #3.

[0055] Example 4

[0056] As a preferred embodiment of the present invention, the raw material composition of the anti-seepage low-shrinkage inorganic coating disclosed in this embodiment is shown in Table 4.

[0057] Table 4. Raw material composition of the seepage-proof, low-shrinkage inorganic coating in Example 4.

[0058]

[0059]

[0060] In this embodiment, the cement material includes the following components by mass percentage: 27 wt% low-heat silicate cement, 30 wt% high-magnesium low-heat silicate cement, and 43 wt% rapid-hardening sulfoaluminate cement.

[0061] According to the mass fractions of each raw material in Table 4, the preparation method described above was used to obtain the anti-seepage, low-shrinkage inorganic coating #4.

[0062] Example 5

[0063] As a preferred embodiment of the present invention, the raw material composition of the anti-seepage low-shrinkage inorganic coating disclosed in this embodiment is shown in Table 5.

[0064] Table 5. Raw material composition of the seepage-proof, low-shrinkage inorganic coating in Example 5.

[0065]

[0066]

[0067] In this embodiment, the cement material includes the following components by mass percentage: 32 wt% low-heat silicate cement, 35 wt% high-magnesium low-heat silicate cement, and 33 wt% rapid-hardening sulfoaluminate cement.

[0068] According to the mass fractions of each raw material in Table 5, the preparation method described above was used to obtain the anti-seepage, low-shrinkage inorganic coating #5.

[0069] Example 6

[0070] As a preferred embodiment of the present invention, the raw material composition of the anti-seepage low-shrinkage inorganic coating disclosed in this embodiment is shown in Table 6.

[0071] Table 6. Raw material composition of the anti-seepage, low-shrinkage inorganic coating in Example 6.

[0072]

[0073] In this embodiment, the cement material includes the following components by mass percentage: 33 wt% low-heat silicate cement, 37 wt% high-magnesium low-heat silicate cement, and 30 wt% rapid-hardening sulfoaluminate cement.

[0074] According to the mass fractions of each raw material in Table 6, the preparation method described above was used to obtain the anti-seepage, low-shrinkage inorganic coating #6.

[0075] Comparative Example 1

[0076] In this comparative example, except that ordinary silicate cement was used to replace low-heat silicate cement and high-magnesium low-heat silicate cement, everything else was the same as in Example 1, resulting in comparative coating #1.

[0077] Comparative Example 2

[0078] In this comparative example, except that ordinary silicate hydrophobic agent was used to replace glyceryl stearate as hydrophobic agent, everything else was the same as in Example 1, and comparative coating #2 was obtained.

[0079] Comparative Example 3

[0080] In this comparative example, except that sodium silicate was not used in the additives, everything else was the same as in Example 1, resulting in comparative coating #3.

[0081] Test case

[0082] The coatings of Examples 1-6 and Comparative Examples 1-3 were tested. The 7-day impermeability pressure, 7-day tensile bond strength, 3-day flexural strength, and 3-day compressive strength were tested according to the standard GB 23440-2009. To test the shrinkage performance of the inorganic coating, this invention refers to the standard JGJ / T 70-2009. The mass ratio of coating:sand:water = 1:3:0.35, where sand is ISO standard sand. The test results are shown in Table 7.

[0083] Table 7 Test results of each coating

[0084]

[0085] As shown in Table 7, compared with Comparative Example 1, the coating of the present invention has a smaller 28-day shrinkage rate; compared with Comparative Example 2, the coating of the present invention has a higher 7-day impermeability pressure; and compared with Comparative Example 3, the coating of the present invention has higher 3-day flexural strength and 3-day compressive strength.

[0086] Finally, it should be noted that the above embodiments are merely preferred embodiments of the present invention used to illustrate the technical solutions of the present invention, and are not intended to limit the invention, nor are they intended to limit the patent scope of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. That is to say, any changes or refinements made to the main design concept and spirit of the present invention that are not of substantial significance, but whose technical problems are still consistent with the present invention, should be included within the protection scope of the present invention. In addition, the direct or indirect application of the technical solutions of the present invention to other related technical fields are similarly included within the patent protection scope of the present invention.

Claims

1. A water-resistant, low-shrinkage inorganic coating, characterized in that, Including the following raw materials by weight: 40-60 parts of cement material; 15-30 parts of active mixed material; 5-15 parts plaster; 5-15 parts talcum powder; 0-2 parts of glyceryl stearate; 4.7 to 6.7 parts of admixture; The cement material comprises the following components by mass percentage: 20-35 wt% low-heat silicate cement, 30-50 wt% high-magnesium low-heat silicate cement, and 20-43 wt% rapid-hardening sulfoaluminate cement. The mineral composition of the low-heat silicate cement is: 20~35wt%C3S, 40~60wt%C2S, 2~7%C3A, and 10~20%C4AF; the mineral composition of the high-magnesium low-heat silicate cement is: 20~35wt%C3S, 35~60wt%C2S, 1~8wt%C3A, and 10~25wt%C4AF, with an MgO content of 3~8wt%; the mineral composition of the rapid-hardening sulfoaluminate cement is: 50~70wt%C4A3S, 10~35wt%C2S, and 3~8wt%C4AF.

2. The impermeable, low-shrinkage inorganic coating according to claim 1, characterized in that, The active mixed material is at least one of silica fume, fly ash, and blast furnace slag powder.

3. The impermeable, low-shrinkage inorganic coating according to claim 1, characterized in that, The gypsum is industrial solid waste phosphogypsum, with a specific surface area of ​​500~700 m². 2 / kg.

4. The impermeable, low-shrinkage inorganic coating according to claim 1, characterized in that, The talc powder is industrial grade talc powder with a fineness of 3000 mesh.

5. The impermeable, low-shrinkage inorganic coating according to claim 1, characterized in that, The stearic acid glyceride is glyceric monostearate.

6. The impermeable, low-shrinkage inorganic coating according to claim 1, characterized in that, The additive is at least one of sodium silicate, defoamer, water-reducing agent, lithium carbonate, hydroxypropyl methylcellulose, and redispersible latex powder.

7. The impermeable, low-shrinkage inorganic coating according to claim 6, characterized in that, The hydroxypropyl methylcellulose is a hydroxypropyl methylcellulose with a viscosity of 50,000.

8. A method for preparing an anti-permeability, low-shrinkage inorganic coating according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. After uniformly mixing cementitious materials, active admixtures, gypsum, talc powder and glyceryl stearate, the mixture is ball-milled to obtain powder. The ball milling speed is 200~400r / s, the ball milling time is 10~40min, and the powder particle size is 5~20μm. S2. Stir the powder and additives obtained in S1 at low speed for 60 seconds, add water and continue stirring at low speed for 30 seconds, and finally stir at high speed for 60 seconds to obtain a mixed slurry. The mass ratio of the powder to water is 1:0.

25. S3. Pour the mixed slurry into the mold, vibrate to form, cure, and demold to obtain the seepage-proof, low-shrinkage inorganic coating.

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