Cement-based capillary crystalline waterproof coating

Abstract

The invention provides a cement-based permeable crystallization type waterproof coating, which is prepared from the following ingredients in parts by weight: 300 to 370 parts of grey cement, 450 to 550 parts of river sand, 20 to 40 parts of metakaolin, 70 to 120 parts of waterproof rubber powder, 1 to 3 parts of polypropylene fibers and 3 to 5 parts of shell-core structure water repellents. Wherein the shell-core structure water repellent is of a structure which takes silicate as a core and an organosilicon compound as a shell and is formed by grafting silicate and the organosilicon compound through a silane coupling agent. The ash cement and the river sand are used as base materials, the shell-core structure water repellent is dispersed in the ash cement and the river sand, and silicate in the core structure, the ash cement and the river sand are hydrated to generate crystals with concrete, so that pores in the coating can be filled and sealed, and the waterproof performance is improved; and the organosilicon compound and the waterproof rubber powder in the shell structure have a synergistic effect, and a hydrophobic coating is formed on the surface of the coating, so that the permeation of water is effectively prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of wall coatings, and particularly to a cement-based penetrating crystalline waterproof coating. Background Art

[0002] In industrial and civil reinforced concrete construction projects, due to the poor anti-seepage and waterproof performance of concrete materials, cracks are likely to occur on the surface of buildings, resulting in water leakage. If the method of laying waterproof membranes or brushing coatings on the concrete surface is adopted, not only the cost is high and the construction method is complex, but also there are problems such as poor durability and environmental pollution.

[0003] Cement-based penetrating crystalline waterproof coating is a new type of waterproof coating in China. It is mainly composed of Portland cement, quartz sand and a variety of special active chemical substances. The active chemical substances usually include surfactants, complexing catalysts and active components of cement hydration reaction, etc. During use, the waterproof coating can be directly mixed with concrete or cement mortar and stirred evenly for construction; it can also be applied on the surface of concrete or cement mortar, and the active substances in it penetrate into the base layer and react with the hydrates in the base layer cement to form crystals insoluble in water to block fine cracks.

[0004] Chinese Patent CN103755286A discloses a high-efficiency cement-based penetrating crystalline waterproof coating, which includes the following raw materials in parts by weight: 40-70% of Portland cement, 12-23% of high-activity masterbatch, 20-30% of quartz sand, 0.3-1.2% of catalyst and 1.2-3% of dispersant. It is a powdery material made of Portland cement and quartz sand as the base materials and incorporated with active chemical substances. After being stirred and formulated with water, it can be brushed or sprayed on the surface of cement concrete, or it can be sprinkled and pressed into the surface of incompletely solidified cement concrete in dry powder form to improve the anti-seepage performance of concrete.

[0005] Currently, the existing cement-based penetrating crystalline waterproof coatings generally have problems such as low toughness. After being impacted or vibrated, the waterproof coating on the surface of the concrete is likely to fall off, etc., and then the secondary crystallization cannot be realized, thus losing the corresponding waterproof performance and having low waterproof durability.

[0006] Therefore, there is an urgent need for a waterproof coating with high toughness, good waterproof effect and capable of multiple crystallization. Summary of the Invention

[0007] (1) Technical Problems to be Solved

[0008] In view of the deficiencies of the prior art, the present invention provides a cement-based penetrating crystalline waterproof coating, which uses grey cement and river sand as base materials, penetrates into the interior of concrete through a water repellent with a core-shell structure, reacts with the oxides in the concrete, forms water-insoluble crystals in the concrete, blocks fine cracks, and is compounded with polypropylene fibers at the same time to enhance the toughness of the coating, thus solving the problems raised in the above-mentioned background art.

[0009] (II) Technical solutions

[0010] To achieve the above objectives, the present invention is realized through the following technical solutions:

[0011] According to the first aspect of the present invention, there is provided a cement-based penetrating crystalline waterproof coating, which, by weight, comprises 300-370 parts of grey cement, 450-550 parts of river sand, 20-40 parts of metakaolin, 70-120 parts of waterproof rubber powder, 1-3 parts of polypropylene fiber, and 3-5 parts of a core-shell structured water repellent;

[0012] Among them, the core-shell structured water repellent is formed by grafting silicate with an organosilicon compound through a silane coupling agent, having a structure with silicate as the core and the organosilicon compound as the shell.

[0013] The present invention uses grey cement and river sand as base materials. The core-shell structured water repellent is formed by grafting silicate and an organosilicon compound through a silane coupling agent. Silicate, as the core, has excellent compatibility and bonding force with cement-based materials. The organosilicon compound, as the shell, provides low surface energy hydrophobicity. The silane coupling agent enables the silicate and the organosilicon compound to be tightly bonded through chemical bonding. Due to the special core-shell structured water repellent, not only a hydrophobic layer is formed on the surface of the coating, but also the overall waterproof effect is enhanced through the synergistic action of crystallization and hydrophobicity inside. In addition, the synergistic action of the organosilicon compound and the waterproof rubber powder makes the surface of the coating not easily wetted by water, effectively preventing the penetration of moisture. At the same time, the crystals generated by cement hydration combine with the silicate core, further filling and sealing the pores in the coating and improving the waterproof performance. The addition of polypropylene fiber effectively enhances the toughness of the coating, reduces the generation of cracks, and further reduces the risk of moisture penetration.

[0014] Preferably, the preparation method of the core-shell structured water repellent is: dispersing silicate, an organosilicon compound, and a silane coupling agent in water, filtering, and drying for preparation;

[0015] Among them, the organosilicon compound is selected from at least one of polymethylhydrosiloxane, vinyltriethoxysilane, or isobutyltriethoxysilane;

[0016] The silane coupling agent is selected from at least one of γ-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-methylpropyltrimethoxysilane, and diphenyldimethoxysilane.

[0017] In the present invention, the selected organosilicon compound has excellent film-forming property and hydrophobicity, and can effectively perform waterproofing. The silanol group or silicon halide group of the silane coupling agent reacts with the hydroxyl groups on the surface of the silicate to form stable Si-O-Si bonds. The organic functional groups of the silane coupling agent are chemically bonded to the organosilicon compound, serving as a "bridge" between the silicate and the organic compound. When the coating has fine cracks due to impact or vibration, the core-shell structured water repellent can recrystallize at the damaged site to restore the waterproof performance.

[0018] Preferably, the mass ratio of the silicate, the organosilicon compound, and the silane coupling agent is 1:2-4:2-4.

[0019] Preferably, by mass parts, it further includes 2-5 parts of cellulose, 2-5 parts of water reducing agent, and 3-7 parts of defoaming agent.

[0020] In the cement-based penetrating crystalline waterproof coating of the present invention, cellulose, water reducing agent, and defoaming agent are also added. Cellulose can not only increase the viscosity of the coating, prevent the settlement of solid particles, and ensure the uniformity of the coating, but also relieve the stress generated during the curing process of the coating and reduce the generation of cracks. The water reducing agent can reduce the water demand, lower the water-binder ratio, and improve the strength and durability of the coating. The defoaming agent can reduce the generation of foam, avoid surface defects of the coating that may be caused by the existence of foam, and thus form a smooth and uniform coating surface. By adding cellulose, water reducing agent, and defoaming agent, the toughness and waterproof performance of the waterproof coating can be further improved.

[0021] Preferably, the water reducing agent is selected from at least one of polycarboxylate-based water reducing agents or aliphatic sulfonate water reducing agents;

[0022] The defoaming agent is selected from at least one of polydimethylsiloxane, silicon dioxide, or calcium carbonate.

[0023] Preferably, the length of the polypropylene fiber is 3-6 mm.

[0024] Preferably, the particle size of the river sand is 70-140 mesh.

[0025] More preferably, by mass parts, it includes 350-370 parts of gray cement, 450-500 parts of river sand, 30-40 parts of metakaolin, 70-100 parts of waterproof rubber powder, 1-2 parts of polypropylene fiber, 3-4 parts of core-shell structured water repellent, 2-3 parts of cellulose, 2-3 parts of water reducing agent, and 3-4 parts of defoaming agent.

[0026] (III) Beneficial effects

[0027] The present invention provides a cement-based penetrating crystalline waterproof coating, which has the following beneficial effects:

[0028] (1) The cement-based penetrating crystalline waterproof coating provided by this solution uses grey cement and river sand as the base materials. The core-shell structured water repellent is dispersed in the grey cement and river sand. The silicate in the core structure, after hydration with the grey cement and river sand, generates crystals with the concrete, which can fill and seal the pores in the coating, improving the waterproof performance. The organosilicon compound and waterproof rubber powder in the shell structure act synergistically to form a water-repellent coating on the surface of the coating, effectively preventing the penetration of moisture. In addition, the organic compound in the shell structure also has a winding effect with the polypropylene fiber, which can improve the toughness of the coating.

[0029] (2) By adding cellulose, water reducer and defoamer to the cement-based penetrating crystalline waterproof coating, the viscosity and fluidity of the waterproof coating can be increased, and the waterproof coating can recrystallize at the damaged part, restoring its waterproof performance. Specific embodiments

[0030] In order to make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present invention.

[0031] Example 1

[0032] (1) Preparation of the core-shell structured water repellent;

[0033] 100 g of silicate, 200 g of polymethylhydrosiloxane and 200 g of γ-aminopropyltriethoxysilane are fully dissolved in water to obtain a mixed solution. After standing for 5 h, it is filtered and air-dried to obtain the core-shell structured water repellent.

[0034] (2) Preparation of the cement-based penetrating crystalline waterproof coating;

[0035] 370 parts of grey cement of type 42.5, 498.6 parts of river sand with a particle size of 70-140 mesh, 30 parts of metakaolin, 90 parts of waterproof rubber powder, 1.5 parts of polypropylene fiber with a length of 6 mm and 3 parts of the core-shell structured water repellent are mixed evenly to prepare a dry powder form of the cement-based penetrating crystalline waterproof coating.

[0036] Example 2

[0037] (1) Preparation of core-shell structured water repellent;

[0038] Dissolve 100 g of silicate, 230 g of vinyltriethoxysilane, and 300 g of 3-glycidoxypropyltrimethoxysilane in water to obtain a mixed solution. After standing for 5 h, filter and air-dry to obtain the core-shell structured water repellent;

[0039] (2) Preparation of cement-based penetrating crystalline waterproof coating;

[0040] Mix 370 parts of type 42.5 gray cement, 498.6 parts of river sand with a particle size of 70 - 140 mesh, 30 parts of metakaolin, 90 parts of waterproof rubber powder, 1.5 parts of polypropylene fiber with a length of 6 mm, and 3 parts of the core-shell structured water repellent evenly to obtain a dry powder form of cement-based penetrating crystalline waterproof coating.

[0041] Example 3

[0042] (1) Preparation of core-shell structured water repellent;

[0043] Dissolve 100 g of silicate, 270 g of isobutyltriethoxysilane, and 400 g of 3-methylpropyltrimethoxysilane in water to obtain a mixed solution. After standing for 5 h, filter and air-dry to obtain the core-shell structured water repellent;

[0044] (2) Preparation of cement-based penetrating crystalline waterproof coating;

[0045] Mix 370 parts of type 42.5 gray cement, 498.6 parts of river sand with a particle size of 70 - 140 mesh, 30 parts of metakaolin, 90 parts of waterproof rubber powder, 1.5 parts of polypropylene fiber with a length of 6 mm, and 3 parts of the core-shell structured water repellent evenly to obtain a dry powder form of cement-based penetrating crystalline waterproof coating.

[0046] Example 4

[0047] (1) Preparation of core-shell structured water repellent;

[0048] Dissolve 100 g of silicate, 300 g of polymethylhydrosiloxane, and 370 g of diphenyldimethoxysilane in water to obtain a mixed solution. After standing for 5 h, filter and air-dry to obtain the core-shell structured water repellent;

[0049] (2) Preparation of cement-based penetrating crystalline waterproof coating;

[0050] Mix 370 parts of type 42.5 gray cement, 498.6 parts of river sand with a particle size of 70 - 140 mesh, 30 parts of metakaolin, 90 parts of waterproof rubber powder, 1.5 parts of polypropylene fiber with a length of 6 mm, and 3 parts of the core-shell structured water repellent evenly to obtain a dry powder form of cement-based penetrating crystalline waterproof coating.

[0051] Example 5

[0052] This example uses the core - shell structured water - repellent prepared in Example 1;

[0053] Preparation of cement - based permeable crystalline waterproof coating:

[0054] Mix 370 parts of gray cement of type 42.5, 498.6 parts of river sand with a particle size of 70 - 140 mesh, 30 parts of metakaolin, 90 parts of waterproof rubber powder, 1.5 parts of polypropylene fiber with a length of 6 mm, 3 parts of the core - shell structured water - repellent, 2.9 parts of cellulose, 2 parts of polycarboxylate - based water - reducing agent, and 2 parts of polydimethylsiloxane evenly to obtain a dry - powder - type cement - based permeable crystalline waterproof coating.

[0055] Example 6

[0056] This example uses the core - shell structured water - repellent prepared in Example 1;

[0057] Preparation of cement - based permeable crystalline waterproof coating:

[0058] Mix 350 parts of gray cement of type 42.5, 450 parts of river sand, 35 parts of metakaolin, 70 parts of waterproof rubber powder, 2 parts of polypropylene fiber with a length of 6 mm, 4 parts of the core - shell structured water - repellent, 2 parts of cellulose, 3 parts of aliphatic sulfonate water - reducing agent, and 3 parts of silicon dioxide evenly to obtain a dry - powder - type cement - based permeable crystalline waterproof coating.

[0059] Example 7

[0060] This example uses the core - shell structured water - repellent prepared in Example 1;

[0061] Preparation of cement - based permeable crystalline waterproof coating:

[0062] Mix 300 parts of gray cement of type 42.5, 550 parts of river sand, 20 parts of metakaolin, 70 parts of waterproof rubber powder, 1 part of polypropylene fiber with a length of 3 mm, 3 parts of the core - shell structured water - repellent, 5 parts of cellulose, 5 parts of polycarboxylate - based water - reducing agent, and 7 parts of calcium carbonate evenly to obtain a dry - powder - type cement - based permeable crystalline waterproof coating.

[0063] Comparative Example 1

[0064] A cement - based permeable crystalline waterproof coating, comprising 370 parts of gray cement of type 42.5, 498.6 parts of river sand with a particle size of 70 - 140 mesh, 30 parts of metakaolin, 90 parts of waterproof rubber powder, 1.5 parts of polypropylene fiber with a length of 6 mm, and 3 parts of polymethylhydrogensiloxane.

[0065] Performance test:

[0066] For the cementitious capillary crystalline waterproof coatings obtained in Examples 1 to 7 and Comparative Example 1, the experimental materials and ratios are specified in Part 7 of the national standard GB18445-2012 Cementitious Capillary Crystalline Waterproof Coating; concrete specimens are made in accordance with the relevant provisions of the national standard GB50081-2016 Standard Test Method for Mechanical Properties of Ordinary Concrete; in accordance with the test methods specified in Part 7 of the national standard GB18445-2012 Cementitious Capillary Crystalline Waterproof Coating, the wet base surface bonding strength, anti-seepage strength, compressive strength, tensile strength and recrystallization anti-seepage strength of the concrete specimens are tested, and the results are shown in Table 1.

[0067] Table 1

[0068]

[0069]

[0070] It can be seen from the data in Table 1 that by using the hydrophobic agent with a core-shell structure, the wet base surface bonding strength, anti-seepage strength, compressive strength, tensile strength and recrystallization anti-seepage strength of the cementitious capillary crystalline waterproof coatings in Examples 1 to 7 are all better than those of the cementitious capillary crystalline waterproof coating in Comparative Example 1. In Examples 5 to 7, cellulose, water reducer and defoamer are added, and the waterproof performance of the cementitious capillary crystalline waterproof coating is better.

[0071] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A cementitious capillary crystalline waterproof coating, characterized in that: By weight parts, it includes 300 - 370 parts of grey cement, 450 - 550 parts of river sand, 20 - 40 parts of metakaolin, 70 - 120 parts of waterproof rubber powder, 1 - 3 parts of polypropylene fiber and 3 - 5 parts of core-shell structure water repellent agent; Among them, the core-shell structure water repellent agent is formed by grafting silicate with silane coupling agent and organosilicon compound to form a structure with silicate as the core and organosilicon compound as the shell.

2. A cementitious capillary crystalline waterproof coating according to claim 1, characterized in that: The preparation method of the core-shell structure water repellent agent is: dispersing silicate, organosilicon compound and silane coupling agent in water, and preparing after filtration and drying; Among them, the organosilicon compound is selected from at least one of polymethylhydrosiloxane, vinyltriethoxysilane or isobutyltriethoxysilane; The silane coupling agent is selected from at least one of γ-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, diphenyldimethoxysilane; 3. A cementitious capillary crystalline waterproof coating according to claim 2, characterized in that: The mass ratio of the silicate, organosilicon compound and silane coupling agent is 1:2 - 4:2 - 4.

4. A cementitious capillary crystalline waterproof coating according to claim 1, characterized in that: By weight parts, it also includes 2 - 5 parts of cellulose, 2 - 5 parts of water reducing agent and 3 - 7 parts of defoaming agent.

5. A cementitious capillary crystalline waterproof coating according to claim 4, characterized in that: The water reducing agent is selected from at least one of polycarboxylate water reducing agent or aliphatic sulfonate water reducing agent; The defoaming agent is selected from at least one of polydimethylsiloxane, silicon dioxide or calcium carbonate.

6. The cementitious capillary crystalline waterproof coating according to claim 1, characterized in that: The length of the polypropylene fiber is 3 - 6 mm.

7. A cementitious capillary crystalline waterproof coating according to claim 1, characterized in that: The particle size of the river sand is 70 - 140 mesh.

8. A cementitious capillary crystalline waterproof coating according to claim 1, characterized in that: By weight parts, it includes 350 - 370 parts of grey cement, 450 - 500 parts of river sand, 30 - 40 parts of metakaolin, 70 - 100 parts of waterproof rubber powder, 1 - 2 parts of polypropylene fiber, 3 - 4 parts of core-shell structure water repellent agent, 2 - 3 parts of cellulose, 2 - 3 parts of water reducing agent and 3 - 4 parts of defoaming agent.

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