CN114163198B

CN114163198B - High-strength anti-permeability foam concrete and preparation method thereof

Info

Publication number: CN114163198B
Application number: CN202111678499.8A
Authority: CN
Inventors: 张海龙; 赵营; 谭勉志; 冉际忠; 王英伟; 庞西西; 王强; 陈政; 贾元霞
Original assignee: Jidong Cement Chongqing Concrete Co ltd
Current assignee: Jidong Cement Chongqing Concrete Co ltd
Priority date: 2021-12-31
Filing date: 2021-12-31
Publication date: 2022-08-05
Anticipated expiration: 2041-12-31
Also published as: CN114163198A

Abstract

The application relates to the field of building materials, and particularly discloses high-strength anti-permeability foam concrete and a preparation method and application thereof. The high-strength impervious foam concrete comprises the following raw materials: 300 parts of 100-doped cement, 50-150 parts of fly ash, 5-15 parts of fiber mixture, 30-40 parts of river sand, 2-5 parts of water reducing agent, 3-10 parts of foaming agent, 3-5 parts of foam stabilizer, 200 parts of ceramsite 100-doped, 50-150 parts of montmorillonite powder, 4-8 parts of water repellent and 1200 parts of water 100-doped; the preparation method of the porcelain granules comprises the following steps: mixing and ball-milling fly ash, bentonite and red mud, adding water, a foam stabilizer and a pore-forming agent, uniformly stirring to prepare a spherical sample, drying, calcining and cooling to prepare a blank; mixing coal gangue powder, a binder and water, adding the mixture into the green body, uniformly mixing, and drying to prepare an intermediate; the high-strength anti-permeability foam concrete prepared into the ceramsite has the advantages of high compressive strength, good anti-permeability, small heat conductivity coefficient, good thermal insulation performance and capability of self-repairing cracks.

Description

High-strength anti-permeability foam concrete and preparation method thereof

Technical Field

The application relates to the technical field of building materials, in particular to high-strength anti-permeability foam concrete and a preparation method thereof.

Background

The foam concrete, also called foam concrete or light concrete, is a light thermal insulation material containing a large amount of closed bubbles, which is formed by fully foaming a foaming agent in a mechanical mode mainly through a foaming system of a foaming machine, uniformly mixing foam and cement slurry, then pouring or molding by a mold and naturally curing.

As a novel building material, the composite material has the advantages of low density, light weight and heat preservation. And (6) sound insulation. The concrete has the advantages of high anti-seismic performance and the like, but the open porosity of the foam concrete is high, so that the compressive strength of the foam concrete is seriously low, and the application range is greatly limited.

The ceramsite is an artificial building lightweight aggregate, has the properties of light weight and high strength, can increase the compressive strength of the foam concrete, does not influence the self weight of the concrete, and still has the advantage of light weight when being doped into the foam concrete, but has larger water absorption rate, and can cause the increase of the water absorption rate of the foam concrete, the reduction of impermeability and the increase of the heat conductivity coefficient after moisture absorption when being added into the foam concrete, so that the heat insulation performance of the foam concrete is reduced.

In view of the above-mentioned related technologies, the inventors found that the preparation of a high-strength, impervious, and heat-insulating foamed concrete using ceramsite is an urgent problem to be solved.

Disclosure of Invention

In order to improve the impermeability and the thermal insulation performance of foam concrete doped with ceramsite, the application provides high-strength impermeable foam concrete and a preparation method thereof.

In a first aspect, the application provides a high-strength impervious foam concrete, which adopts the following technical scheme:

a high-strength anti-permeability foam concrete comprises the following raw materials in parts by weight: 300 parts of 100-doped cement, 50-150 parts of fly ash, 5-15 parts of fiber mixture, 30-40 parts of river sand, 2-5 parts of water reducing agent, 3-10 parts of foaming agent, 3-5 parts of foam stabilizer, 200 parts of ceramsite 100-doped, 50-150 parts of montmorillonite powder, 4-8 parts of water repellent and 1200 parts of water 100-doped;

the ceramsite is prepared by the following method:

(1) mixing and ball-milling 30-40 parts of fly ash, 20-30 parts of bentonite and 30-40 parts of red mud, adding 20-30 parts of water, 3-4 parts of foam stabilizer and 6-9 parts of pore-forming agent, uniformly stirring to prepare a spherical sample with the particle size of 5-15mm, drying, calcining and cooling to prepare a blank;

(2) mixing 20-30 parts by weight of coal gangue powder, 10-15 parts by weight of binder and 10-15 parts by weight of water, adding the blank prepared in the step (1), uniformly mixing, and drying to prepare an intermediate;

(3) and (3) mixing 10-15 parts by weight of thermoreversible glue with 5-10 parts by weight of water to form a coating solution, uniformly mixing the coating solution with the intermediate prepared in the step (2), and drying to prepare the ceramsite.

By adopting the technical scheme, the coal ash, the fiber mixture, the foaming agent, the montmorillonite powder, the ceramsite and other components are used for preparing the foam concrete, so that the compressive strength of the concrete is enhanced, the ceramsite is prepared from the red mud, the coal ash and the bentonite as main raw materials in the application, a blank body after high-temperature sintering generates enough liquid phase, the liquid phase can wrap gas released by a pore-forming agent reaction to form a pore structure with closed pores as the main part, the inter-pore wall is compact, so that the ceramsite has higher compressive strength, the pore-forming agent with higher content is added in the application, so that more pores are generated on the blank body, the pores are mutually communicated, open pores are convenient for filling coal gangue powder, the coal gangue powder is filled into the communicated pores formed by the blank body under the action of a binder, and then the blank body loaded with coal gangue, namely an intermediate body is wrapped by the thermoreversible glue, thus preparing the ceramsite.

When cement generates hydration heat, the thermoreversible glue is gradually melted, an intermediate coated inside the ceramsite is exposed, the gangue powder is high in water absorption rate and can expand when meeting water, the gangue powder can be filled into air holes in the concrete and block the air holes in the foam concrete, a water permeation channel is blocked, water continues to permeate in the foam concrete effectively all the time, meanwhile, the gangue is used as a water blocking component, the compressive strength of the gangue is higher than that of general high-molecular water-absorbent resin, the self weight of the ceramsite is large, and floating is not prone to occurring.

Preferably, the thermoreversible glue comprises the following components in parts by weight: 1-2 parts of carrageenan, 0.1-0.5 part of defoaming agent, 0.1-0.5 part of plasticizer, 1-2 parts of alkali activator and 0.5-1 part of modified polyester fiber.

By adopting the technical scheme, when hydration heat is generated in concrete, the thermally reversible adhesive is hot-melted, flows in the foam concrete gradually and is filled into air holes, the carrageenan has certain viscosity, the toughness of the carrageenan is increased under the action of the plasticizer, the intermediate can be coated, in addition, the carrageenan has thermal reversibility under the action of calcium ions, potassium ions and the like in the concrete, the defoaming agent can prevent the carrageenan from generating air bubbles and coating the intermediate not tightly, and when the carrageenan is mixed, the coal ash and the like enter the holes to influence the bonding strength of the carrageenan and the intermediate, so that the intermediate coated by the carrageenan falls off when river sand and the like are mixed and hydration heat does not occur.

The modified polyester fiber has smooth surface, can increase the smoothness of ceramsite and improve the fluidity, and when the carrageenan flows in a hot melting way, the modified polyester fiber is filled into the foam concrete along with the flowing of the carrageenan and is mutually overlapped, so that the crack resistance of the concrete is increased, and the impermeability of the concrete is improved.

When the carrageenan is hot-melted, the alkali activator flows along with the carrageenan and enters the concrete, and can generate an excitation effect with the fly ash in the concrete, so that the excitation degree of the fly ash is further increased, and the compressive strength of the concrete is enhanced; in addition, the alkali activator can also contact with the released coal gangue when flowing, thereby activating the coal gangue and enhancing the strength of the concrete.

Preferably, the modified polyester fiber comprises the following components in parts by weight: 1-3 parts of polyester fiber, 2-4 parts of gelatin, 1-2 parts of carbonic anhydrase producing bacteria and 1-3 parts of chitosan.

By adopting the technical scheme, the carbonic anhydrase producing bacteria can produce carbonic anhydrase, and the carbonic anhydrase can combine with carbonate ions in oxygen to react with calcium ions in the concrete to generate calcium carbonate to fill air holes in the concrete, so that the compressive strength is enhanced, the impermeability is increased, cracks in the concrete can be repaired, and the crack resistance is enhanced.

Preferably, the modified polyester fiber is prepared by the following method:

(1) inoculating carbonic anhydrase producing bacteria 2-4 wt% into inactivated beef extract peptone liquid culture medium, culturing at 25-30 deg.C for 24-48 hr at 150- ⁵ -10 ⁶ ) Adding acetic acid solution of chitosan and sodium dodecyl benzene sulfonate into the mixture per mL, performing water bath at 40-50 ℃ for 1-2h, filtering, and washing to prepare an intermediate;

(2) boiling polyester fiber with deionized water for 30-60min, drying, soaking in 10-15% nitric acid solution for 20-24h, washing with deionized water to neutrality, drying, adding 2-5% calcium chloride solution, soaking at room temperature for 20-24h, and drying to obtain pretreated polyester fiber;

(3) heating the pretreated polyester fiber and gelatin, stirring uniformly, spray drying to prepare a coating, and mixing with the intermediate to prepare the modified polyester fiber.

By adopting the technical scheme, as the foam concrete is gradually carbonized after cracks appear, the cracks are gradually expanded, and the service life of the concrete is shortened; therefore, the chitosan is used for coating the carbonic anhydrase producing bacteria, the carbonic anhydrase producing bacteria are coated in the chitosan coating film, and no toughening agent is added in the chitosan solution, so that the chitosan coating film is relatively crisp in texture and is easy to break under the action of stress, the carbonic anhydrase producing bacteria flow out, the carbonic anhydrase producing bacteria in the carbonic anhydrase producing bacteria can produce carbonic anhydrase after being cultured, after the carbonic anhydrase flows out, carbon dioxide can be captured, the dioxygen is promoted to be converted into carbonate, and then the carbonic anhydrase is combined with calcium ions in the sea concrete, and the silence of calcium carbonate is formed on the surface area of the crack, so that the crack is repaired; after being soaked in acid liquor, the polyester fiber is mixed with calcium chloride, calcium ions are loaded on the polyester fiber, and carbonic anhydrase can be generated and combined with the calcium ions on the polyester fiber to generate calcium carbonate, so that the strength of the polyester fiber is enhanced, and the hardness of the polyester fiber is improved.

Preferably, the alkali activator comprises sodium hydroxide, sodium sulfate and phosphogypsum in a mass ratio of 1:0.9-1.1: 1.5-2.

By adopting the technical scheme, the hydroxide ions in the sodium hydroxide can break the silicon-oxygen bond and the aluminum oxygen in the fly ash, so that the silicon-oxygen tetrahedron and aluminum-oxygen octahedron network structures in a vitreous body are damaged, the dissolving amount of active substances in the fly ash particles is increased, the reaction of aluminum oxide, silicon dioxide and calcium hydroxide is accelerated, the production of a gel is promoted, and the phosphogypsum can supplement the calcium content in the fly ash, so that the activated fly ash has more hydrated gel products; the sodium sulfate can ionize sulfate ions, and the sulfate ions react with active aluminum oxide in the vitreous body under the action of calcium ions to generate ettringite which is filled in a cement stone structure, so that the compressive strength of a concrete system is increased.

Preferably, the binder comprises 5-10 parts by weight of polyvinyl alcohol, 3-6 parts by weight of polycrystalline mullite fiber and 1-5 parts by weight of zirconia toughened molybdenum disilicide.

By adopting the technical scheme, the polyvinyl alcohol has certain viscosity, when the ceramsite is prepared, the coal gangue can be bonded in pores of a green body, the polycrystalline mullite and the zirconium oxide toughened molybdenum disilicide can be adhered on the green body, the polycrystalline mullite fiber has low heat conductivity and good heat insulation performance, and the molybdenum disilicide is toughened and reinforced by the zirconium oxide, so that the polycrystalline mullite fiber has good hardness and toughness, the hardness of the ceramsite can be improved, and the compressive strength of the foam concrete can be improved.

Preferably, the preparation method of the zirconium oxide toughened molybdenum disilicide comprises the following steps: mixing and ball-milling the molybdenum disilicide and the zirconium oxide according to the mass ratio of 7:1-3 for 2-3h, and then preserving the heat for 20-30min under the conditions of the temperature of 1200-1300 ℃, the pressure of 45-50MPa and the vacuum degree of 3-4 Pa.

By adopting the technical scheme, the addition of the zirconium oxide plays a role in refining grains, and the addition of the calcium oxide in the molybdenum disilicide is equivalent to the distribution of hard particles on a soft aggregate, so that the molybdenum disilicide has the effect of dispersion strengthening and can obviously improve the compressive strength and the fracture toughness of the molybdenum disilicide.

Preferably, the fiber mixture comprises polypropylene fibers and carbon fibers in a mass ratio of 1: 0.8-1.2.

By adopting the technical scheme, the polypropylene fiber and the carbon fiber can enhance the impact strength and the impermeability of concrete and resist the intrusion of external moisture.

Preferably, the foam stabilizer is cellulose ether, triethanolamine and sodium dodecyl sulfate in a mass ratio of 1:0.7-1: 0.9-1.

By adopting the technical scheme, the cellulose ether has the functions of thickening and water retention, can be adsorbed on the surfaces of cement particles to form emulsion films, reduces the friction force among the particles, improves the foam stability and is favorable for improving the mechanical property of concrete.

In a second aspect, the application provides a preparation method of high-strength anti-permeability foam concrete, which adopts the following technical scheme: a preparation method of high-strength impervious foam concrete comprises the following steps: diluting a foaming agent and water according to a certain proportion to prepare a foaming agent solution, adding a foam stabilizer, and uniformly mixing to prepare foam;

uniformly mixing cement, fly ash, fiber mixture, river sand, water reducing agent, ceramsite, montmorillonite powder and water repellent to prepare slurry;

adding foam into the slurry, mixing and stirring uniformly to prepare a foam concrete mixture, constructing, forming, maintaining and hardening to obtain the high-strength anti-permeability foam concrete.

In summary, the present application has the following beneficial effects:

1. as the ceramsite is adopted to prepare the concrete, and the surface of a green body prepared by calcining the red mud, the fly ash and the bentonite is adhered with the gangue, and then the ceramsite is coated with the thermoreversible glue, the thermoreversible glue can be hot-melted when the concrete generates hydration heat, so that the green body adhered with the gangue powder is released, the gangue absorbs water and expands when meeting water, then air holes nearby the gangue is blocked, a permeation channel of water is blocked, and the impermeability is improved.

2. In the application, carrageenin, a defoaming agent, polyester fiber, an alkali activator and the like are preferably adopted to prepare the thermoreversible glue, because the carrageenin has thermal reversibility under the action of calcium ions, when concrete generates hydration heat, hot melting can be generated to release contents, the polyester fiber can increase the surface smoothness of the carrageenin and improve the fluidity of ceramsite, the alkali activator can increase the excitation degree of fly ash and improve the mechanical property of the concrete when the concrete is mixed, and after the thermoreversible glue is subjected to hot melting, the alkali activator can flow along with the heat activator and contact with coal gangue to excite the coal gangue and improve the compressive strength of the concrete.

3. In the application, chitosan is preferably used for coating carbonic anhydrase producing bacteria, calcium chloride is used for pretreating polyester fibers to load calcium ions on the surfaces of the polyester fibers, then gelatin is used for coating the polyester fibers, when concrete cracks appear, the gelatin and the chitosan are broken under stress, and the carbonic anhydrase producing bacteria produce carbonic anhydrase which can be combined with calcium ions loaded on the polyester fibers or calcium ions in the concrete to capture carbon dioxide, improve the mechanical strength of the polyester fibers, improve the mechanical strength of the concrete and repair the cracks.

Detailed Description

Preparation examples 1 to 3 of modified polyesters

Preparation examples 1-3 carbonic anhydrase bacteria were selected from Wuhanyitai science and technology Co., Ltd, CAS number 9001-03-0; the chitosan is selected from Shanghai Yanghong biological technology Co., Ltd, with a product number of 2764; the sodium dodecyl benzene sulfonate is selected from Suzhou city, which enters fine chemical engineering Co., Ltd, and has a product number of 02; the polyester fiber is selected from Teley chemical fiber products, Inc., with a product number of 5698 and a length of 3 mm.

Preparation example 1: (1) inoculating 1Kg carbonic anhydrase producing bacteria into inactivated beef extract peptone liquid culture medium according to the weight ratio of 2%, culturing at 25 deg.C at 150r/min for 48h, centrifuging, and concentrating until the concentration of carbonic anhydrase producing bacteria is 10 ⁵ Adding 1Kg of chitosan into 3 percent of chitosan acetic acid solution prepared by 1Kg of chitosan and 0.5Kg of sodium dodecyl benzene sulfonate, bathing for 2 hours at 40 ℃, filtering and washing to prepare an intermediate, wherein the carbonic anhydrase producing bacterium is carbonic anhydrase bacterium;

(2) boiling 1Kg of polyester fiber with deionized water for 30min, drying, soaking in 10% nitric acid solution for 24h, washing with deionized water to neutrality, drying, adding 2% calcium chloride solution, soaking at room temperature for 20h, and drying to obtain pretreated polyester fiber;

(3) pretreating polyester fiber and 2Kg gelatin, heating to 55 deg.C, stirring, spray drying to obtain coating, and mixing with intermediate to obtain modified polyester fiber.

Preparation example 2: (1) inoculating 2Kg carbonic anhydrase producing bacteria to inactivated beef extract peptone liquid culture medium according to the weight ratio of 4%, culturing at 30 deg.C for 24h at 180r/min, centrifuging, and concentrating until the concentration of carbonic anhydrase producing bacteria is 10 ⁶ Adding 3% chitosan acetic acid solution prepared from 3Kg of chitosan and 0.5Kg of sodium dodecyl benzene sulfonate into the mixture per mL, carrying out water bath at 50 ℃ for 1h, filtering and washing to prepare an intermediate;

(2) boiling 3Kg of polyester fiber with deionized water for 60min, drying, soaking in 15% nitric acid solution for 20h, washing with deionized water to neutrality, drying, adding 5% calcium chloride solution, soaking at room temperature for 24h, and drying to obtain pretreated polyester fiber;

(3) pretreating polyester fiber and 4Kg gelatin, heating to 55 deg.C, stirring, spray drying to obtain coating, and mixing with intermediate.

Preparation example 3: the difference from preparation example 1 is that step (2) was not performed.

Preparation examples 4 to 14 of Haydite

The defoaming agent in preparation examples 4 to 14 was selected from the Dongmi science and technology Co., Ltd, type DW-1015; the foam stabilizer is selected from the corridor Dinghe energy-saving technology limited company, and the model is DFH-303; the polyvinyl alcohol is selected from Ningpo republic of chemical industry Co., Ltd, with the product number of 2488; the carrageenan is selected from Shanxi Tang Biotech Co., Ltd, with a product number of 1235.

Preparation example 4: (1) mixing and ball-milling 30Kg of fly ash, 20Kg of bentonite and 30Kg of red mud, adding 20Kg of water, 3Kg of foam stabilizer and 6Kg of pore-forming agent, stirring uniformly to prepare a spherical sample with the particle size of 5mm, drying at 105 ℃ for 12h, calcining in a muffle furnace at 450 ℃ for 15min, heating to 1150 ℃ at the heating rate of 15 ℃/min, preserving heat for 25min, cooling and preparing a blank, wherein the main chemical compositions of the fly ash, the bentonite and the red mud are shown in Table 1, and the pore-forming agent is sodium bicarbonate; (2) mixing 20Kg of coal gangue powder, 10Kg of binder and 10Kg of water, adding the mixture into the green body prepared in the step (1), uniformly mixing, and drying to prepare an intermediate, wherein the binder is polyvinyl alcohol;

(3) and (3) mixing 10Kg of thermoreversible glue with 5Kg of water to form a coating solution, uniformly mixing the coating solution with the intermediate prepared in the step (2), and drying to prepare ceramsite, wherein the thermoreversible glue is prepared from 1Kg of carrageenan, 0.1Kg of defoaming agent and 0.1Kg of plasticizer, and the plasticizer is chlorinated paraffin.

TABLE 1 main chemical compositions of fly ash, bentonite and red mud

w/％	SiO ₂	Al ₂ O ₃	Fe ₂ O ₃	CaO	MgO	Na ₂ 0	K ₂ O	Loss
									Fly ash	57.39	18.97	3.31	3.23	4.55	1.26	1.64	6.02
Bentonite clay	72.13	12.71	1.68	2.74	2.31	0.56	0.34	6.31
									Red mud	35.25	8.52	8.33	29.93	3.41	3.18	1.15	9.23

Preparation example 5: (1) mixing and ball-milling 40Kg of fly ash, 30Kg of bentonite and 40Kg of red mud, adding 30Kg of water, 4Kg of foam stabilizer and 9Kg of pore-forming agent, stirring uniformly to prepare a spherical sample with the particle size of 15mm, drying at 105 ℃ for 12h, calcining in a muffle furnace at 450 ℃ for 15min, heating to 1150 ℃ at the heating rate of 15 ℃/min, preserving heat for 25min, cooling and preparing a blank, wherein the main chemical compositions of the fly ash, the bentonite and the red mud are shown in Table 1, and the pore-forming agent is sodium bicarbonate;

(2) mixing 30Kg of coal gangue powder, 15Kg of binder and 15Kg of water, adding the mixture into the green body prepared in the step (1), uniformly mixing, and drying to prepare an intermediate, wherein the binder is polyvinyl alcohol;

(3) and (3) mixing 15Kg of thermoreversible glue and 10Kg of water to form a coating solution, uniformly mixing the coating solution with the intermediate prepared in the step (2), and drying to prepare ceramsite, wherein the thermoreversible glue is prepared from 2Kg of carrageenan, 0.5Kg of defoaming agent and 0.5Kg of plasticizer, and the plasticizer is chlorinated paraffin.

Preparation example 6: the difference from preparation example 4 is that the thermoreversible glue is prepared from 1Kg of carrageenan, 0.1Kg of defoamer, 0.1Kg of plasticizer, 1Kg of alkali activator and 0.5Kg of modified polyester fiber, wherein the plasticizer is chlorinated paraffin, the alkali activator is sodium hydroxide, sulfuric acid and phosphogypsum in a mass ratio of 1:0.9:1.5, the modified polyester fiber is prepared from preparation example 1, and the analysis of active ingredients of the phosphogypsum is shown in Table 2.

Table 2 analysis of active ingredients of phosphogypsum

w/％	CaO	SiO ₂	MgO	Al ₂ O ₃	Fe ₂ O ₃	P ₂ O ₅	H ₂ 0
								Phosphogypsum	49.6	36.4	1.2	4.8	2.4	1.2	4.2

Preparation example 7: the difference from the preparation example 4 is that the thermoreversible glue is prepared from 1Kg of carrageenan, 0.1Kg of defoamer, 0.1Kg of plasticizer, 2Kg of alkali activator and 1Kg of modified polyester fiber, wherein the plasticizer is chlorinated paraffin, the alkali activator is sodium hydroxide, sulfuric acid and phosphogypsum in a mass ratio of 1:1:2, and the modified polyester fiber is prepared from the preparation example 1.

Preparation example 8: the difference from preparation example 6 is that modified polyester fiber was produced from preparation example 2.

Preparation example 9: the difference from preparation example 6 is that the modified polyester fiber was prepared by preparation example 3.

Preparation example 10: the difference from preparation example 6 is that no alkali activator is added.

Preparation example 11: the difference from preparation example 6 is that the binder comprises 5Kg of polyvinyl alcohol, 3Kg of polycrystalline mullite fiber and 1Kg of zirconia-toughened molybdenum disilicide, and the preparation method of the zirconia-toughened molybdenum disilicide comprises the following steps: mixing molybdenum disilicide and zirconia according to the mass ratio of 7:1, ball-milling for 3h, and then preserving heat for 30min under the conditions of 1200 ℃ of temperature, 45MPa of pressure and 3Pa of vacuum degree.

Preparation example 12: the difference from preparation example 6 is that the binder comprises 10Kg of polyvinyl alcohol, 6Kg of polycrystalline mullite fiber and 5Kg of zirconia-toughened molybdenum disilicide, and the preparation method of the zirconia-toughened molybdenum disilicide comprises the following steps: mixing and ball-milling molybdenum disilicide and zirconia according to the mass ratio of 7:3 for 2h, and then preserving heat for 20min under the conditions of 1300 ℃ of temperature, 50MPa of pressure and 4Pa of vacuum degree.

Preparation example 13: the difference from preparation example 12 is that polycrystalline mullite fiber is not added to the binder.

Preparation example 14: the difference from preparation example 12 is that zirconia toughened molybdenum disilicide is not added to the binder.

Examples

In the embodiment, the polycarboxylate superplasticizer is selected from the chemical technology limited company of Jinan Beibei, and the model is FDN-C; the foaming agent is selected from Chongqing Hengheng building science and technology company, and the batch is TP-20210919; the organosilicon water repellent is selected from Bailijia science and technology limited company in Guangzhou, and the model is SHP-50; the hydroxypropyl methylcellulose is selected from Ningpo republic of chemical industry Co., Ltd, and is HPMC; the polypropylene fiber is selected from Taian Hua engineering materials, Limited liability company, with the product number of X11 and the length of 19 mm; the carbon fiber is selected from Cinciki carbon fiber products, Inc. of Yixing, with a product number of 200; the montmorillonite powder is KX-F4;

example 1: the high-strength anti-permeability foam concrete comprises the following raw materials, wherein the raw materials are shown in table 3, cement in table 3 is P.O42.5 cement, fly ash is II-grade fly ash, a fiber mixture is polypropylene fiber and carbon fiber in a mass ratio of 1:0.8, river sand has a particle size of 100 meshes, a water reducing agent is a polycarboxylic acid water reducing agent, a foam stabilizer is cellulose ether, triethanolamine and sodium dodecyl sulfate in a mass ratio of 1:0.7:0.9, the cellulose ether is hydroxypropyl methyl cellulose, ceramsite is prepared according to preparation example 4, a water repellent is an organic silicon water repellent, and montmorillonite powder has a particle size of 600 meshes.

The preparation method of the high-strength impervious foam concrete comprises the following steps:

s1, diluting a foaming agent and water according to a certain proportion to prepare a foaming agent solution, adding a foam stabilizer, uniformly mixing, and preparing into foam by using a compressed air foaming device;

s2, uniformly mixing cement, fly ash, fiber mixture, river sand, a water reducing agent, ceramsite, montmorillonite powder and a water repellent to prepare slurry;

and S3, adding the foam into the slurry, mixing and stirring uniformly to prepare a foam concrete mixture, constructing, forming, maintaining and hardening to obtain the high-strength impervious foam concrete.

TABLE 3 raw material amounts of high-strength anti-permeability foam concrete in examples 1 to 3

Examples 2 to 3: the high-strength anti-permeability foam concrete is different from the foam concrete in example 1 in that the raw materials are used in the amount shown in table 3, the fiber mixture is polypropylene fibers and carbon fibers in a mass ratio of 1:1.2, and the foam stabilizer is cellulose ether, triethanolamine and sodium dodecyl sulfate in a mass ratio of 1:1: 1.

Example 4: a high-strength anti-permeability foam concrete is different from the foam concrete in example 1 in that carbon fibers are not added into a fiber mixture.

Example 5: a high-strength impervious foam concrete is different from the concrete in example 1 in that the preparation examples of the ceramsite are selected as shown in Table 4.

TABLE 4 selection of preparation examples of the ceramisites in example 1 and examples 5-17

Examples	Preparation of ceramsite	Examples	Preparation of ceramsite
				Example 1	Preparation example 4	Example 10	Preparation example 10
Example 5	Preparation example 5	Example 11	Preparation example 11
				Example 6	Preparation example 6	Example 12	Preparation example 12
Example 7	Preparation example 7	Example 13	Preparation example 13
				Example 8	Preparation example 8	Example 14	Preparation example 14
Example 9	Preparation example 9	/	/

Comparative example

Comparative example 1: a high-strength impervious foam concrete is different from the foam concrete prepared in the example 1 in that when ceramsite is prepared, equal amount of high molecular water-absorbing resin is used for replacing coal gangue powder, and the high molecular water-absorbing array is selected from Jinan Huadi Gongmao Co., Ltd, and the model is HD 1801.

Comparative example 2: a high-strength impermeability foam concrete is different from example 1 in that an equal amount of polyvinyl alcohol is used instead of the thermoreversible glue.

Comparative example 3: the high-strength anti-permeability foam concrete is different from the foam concrete in example 1 in that the ceramsite prepared in the application is replaced by the commercially available ceramsite, and the commercially available ceramsite is selected from novel building materials Co., Ltd of Wanyu, Lantian county and has the specification of 10-30 mm.

Comparative example 4: a high-strength impervious foam concrete is different from that in example 1 in that a water repellent is not added.

Comparative example 5: a foamed concrete comprising the steps of:

preparation of S1 additive: weighing 4Kg of polycarboxylic acid water reducing agent, adding 1Kg of dodecyl dimethyl amine oxide and 7Kg of glass fiber powder, and uniformly mixing to obtain the additive.

Preparation of S2 foaming liquid: weighing 1.5Kg of sodium dodecyl sulfate, adding 2Kg of sodium dodecyl benzene sulfonate, 2.5Kg of casein and 1.5Kg of corn starch, and mixing uniformly to obtain the foaming agent. And adding 40Kg of water into the foaming agent, and uniformly mixing to obtain the foaming liquid.

S3 slurry preparation, wherein the slurry preparation comprises the following steps: modification of S3A zeolite powder: weighing 15Kg of zeolite powder, adding 75Kg of purified water, adding 18Kg of ammonium chloride, stirring at the rotating speed of 200 r/min, heating to 80 ℃ for modification reaction for 300min, filtering, washing a filter cake with 45Kg of purified water, drying the filter cake at 70 ℃ for 120min, then roasting at 550 ℃ for 200min to prepare dry powder, crushing the dry powder by a crusher, sieving by a sieve with the aperture of 150 mu m, and continuously crushing particles with the particle size of more than 150 mu m until the particle size is not more than 150 mu m to prepare the modified zeolite powder; S3B mixing: weighing 190Kg of ceramsite, adding 120Kg of fly ash and 80Kg of fine aggregate, adding the modified zeolite powder prepared in the step S3A, and mixing uniformly to obtain powder; weighing 130Kg of water, transferring the water into a white plastic barrel with stirring and scales, and observing the volume of the material through the scales on the white plastic barrel; stirring at the rotating speed of 300 r/min for 2min, adding the admixture prepared in the step S1, adding 20Kg of neutral silica sol (HN 3020, 30% of silica, 0.08% of sodium oxide, and the balance of water, and the median particle size (corresponding to the cumulative particle size distribution of 50%) D50 of the silica sol of 22.5nm) and 220Kg of cement, and continuously stirring for 4min to obtain slurry.

S4 preparation of foam concrete: transferring the foaming liquid prepared in the step S2 into a white plastic barrel with scales, observing the volume of the material through the scales on the white plastic barrel, foaming the foaming liquid through a foaming machine until the foam volume is 3 times of the size of the pulp, and preparing foam pulp; and (4) adding the foam slurry into the slurry prepared in the step S3, and uniformly mixing to obtain a foam concrete product.

Performance test

Concrete slurry was prepared according to the methods of the examples and comparative examples, and the properties of the concrete were measured with reference to the following methods, and the results of the measurements are recorded in table 5.

1. Compressive strength and water absorption: detecting by referring to JG/T266-2011 foam concrete;

2. coefficient of thermal conductivity: according to a method disclosed in GB/T10294-2008 'determination of steady-state thermal resistance and related characteristics of thermal insulation material for protective heat plate', a foam concrete thermal conductivity tester (HS-DR-1, Shanghai and Cheng instruments science and technology Co., Ltd.) is used for testing the thermal conductivity;

3. repairing performance: preparing the concrete slurry into a plurality of test pieces with the size of 100mm multiplied by 100mm, presetting cracks after curing for 28 days, loading and presetting the cracks by adopting a three-point method through an electro-hydraulic servo pressure tester, specifically, debugging the pressure tester to load at the speed of 0.05mm/min, stopping loading when 0.1-0.3mm cracks appear at the lowest side of the pulled side of the test piece, unloading after keeping the load for 90s, watering the test piece for curing and measuring the width of the cracks.

TABLE 5 results of testing the properties of the foamed concrete

It can be seen from the combination of the examples and the contents in table 5 that, the ceramsite prepared in preparation example 4 in examples 1-3 has a compressive strength of 19MPa or more after 28 days, and has the advantage of high strength, and in addition, the water absorption rate is less than 2.3%, the water absorption rate is low, the impermeability is good, the thermal conductivity is low, and the heat preservation performance is high.

Example 4 compared to example 1, the fiber mixture without carbon fibers, in example 4, the compressive strength was reduced, the water absorption was increased, and the compressive strength and impermeability were reduced compared to example 1.

The ceramsite prepared in preparation example 5 is adopted in example 5, and similarly to example 1, the foam concrete prepared in example 5 has high strength, low water absorption rate and strong impermeability.

Compared with the embodiment 1, the compression strength of the foam concrete prepared in the embodiment 6 and the embodiment 7 is further enhanced, the width of the preset crack is obviously reduced after 28 days, and the self-repairing effect is good because the modified polyester fiber and the alkali activator prepared in the preparation 1 are added into the thermoreversible glue which is respectively prepared from the ceramsite prepared in the preparation 6 and the ceramsite prepared in the preparation 7 in the embodiment 6 are adopted.

In example 8, the ceramsite prepared in preparation example 8 is adopted, wherein the modified polyester fiber is prepared in preparation example 2, and compared with example 6, the compressive strength and the water absorption rate of the foam concrete are not greatly different.

In example 9, the ceramsite prepared in preparation example 9 is used, wherein the modified polyester fiber is prepared from the ceramsite prepared in preparation example 3, and since calcium ions are not loaded on the polyester fiber when the polyester fiber is prepared in preparation example 3, compared with example 6, the repair effect is reduced compared with example 6 because the preset crack is only repaired to 0.21mm after 28 days.

In example 10, the ceramsite prepared in preparation example 10 was used, and the alkali activator was not added to the thermoreversible gel, and the compressive strength of the foamed concrete was reduced compared with example 6, which shows that the compressive strength of the foamed concrete can be improved by adding the alkali activator.

In example 11 and example 12, the ceramsite prepared in preparation example 11 and preparation example 12 were used, respectively, and the binder was prepared from polyvinyl alcohol, polycrystalline mullite fiber and zirconia toughened molybdenum disilicide as compared with example 6, and table 5 shows that the 28-day compressive strength of the foam concrete was significantly enhanced.

The ceramsite prepared in preparation example 13 and preparation example 14 was used in example 13 and example 14, respectively, and Table 5 shows that the compressive strength of the foamed concrete prepared in example 13 and example 14 was lower than that of example 13, and the compressive strength was decreased.

In comparative example 1, the same amount of the high molecular water-absorbent resin was used instead of the coal gangue powder, and table 4 shows that the compressive strength of the foam concrete is reduced, which indicates that the compressive strength of the concrete can be improved by using the coal gangue powder for water blocking.

In the comparative example 2, polyvinyl alcohol is used for replacing the thermal reversible adhesive, and the polyvinyl alcohol is quickly dissolved when meeting water, so that a blank body and the like are difficult to coat, the absorption rate of concrete is high, and the compressive strength is reduced.

In comparative example 3, the commercially available ceramsite was used, and compared with example 1, the concrete had a high compressive strength, but a high water absorption, a poor impermeability, and a poor thermal insulation property.

In comparative example 4, the water repellent was not added, and the concrete still had higher compressive strength, but increased water absorption and deteriorated thermal insulation performance.

Comparative example 5 is a foam concrete containing ceramsite prepared by the prior art, which has the advantages of compressive strength of only C2 grade, low strength, high heat conductivity coefficient and poor heat insulation performance.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.

Claims

1. The high-strength anti-permeability foam concrete is characterized by comprising the following raw materials in parts by weight:

300 parts of 100-doped cement, 50-150 parts of fly ash, 5-15 parts of fiber mixture, 30-40 parts of river sand, 2-5 parts of water reducing agent, 3-10 parts of foaming agent, 3-5 parts of foam stabilizer, 200 parts of ceramsite 100-doped, 50-150 parts of montmorillonite powder, 4-8 parts of water repellent and 1200 parts of water 100-doped;

the ceramsite is prepared by the following method:

(3) mixing 10-15 parts by weight of thermoreversible glue with 5-10 parts by weight of water to form a coating liquid, uniformly mixing the coating liquid with the intermediate prepared in the step (2), and drying to prepare ceramsite;

the thermoreversible glue comprises the following components in parts by weight: 1-2 parts of carrageenan, 0.1-0.5 part of defoaming agent, 0.1-0.5 part of plasticizer, 1-2 parts of alkali activator and 0.5-1 part of modified polyester fiber;

the modified polyester fiber comprises the following components in parts by weight: 1-3 parts of polyester fiber, 2-4 parts of gelatin, 1-2 parts of carbonic anhydrase producing bacteria and 1-3 parts of chitosan.

2. The high strength impervious foam concrete according to claim 1, wherein said modified polyester fibers are prepared by the following method:

(1) inoculating carbonic anhydrase producing bacteria 2-4 wt% into inactivated beef extract peptone liquid culture medium, and culturing at 25-30 deg.C under 150-Centrifuging for 48h, and concentrating to obtain carbonic anhydrase concentration of 10 ⁵ -10 ⁶ Adding acetic acid solution of chitosan and sodium dodecyl benzene sulfonate into the mixture per mL, performing water bath at 40-50 ℃ for 1-2h, filtering, and washing to prepare an intermediate;

3. The high-strength impervious foam concrete according to claim 1, wherein the alkali activator comprises sodium hydroxide, sodium sulfate and phosphogypsum in a mass ratio of 1:0.9-1.1: 1.5-2.

4. The high strength impervious foam concrete according to claim 1, wherein said binder comprises 5-10 parts by weight polyvinyl alcohol, 3-6 parts by weight polycrystalline mullite fiber and 1-5 parts by weight zirconia toughened molybdenum disilicide.

5. The high-strength impervious foam concrete according to claim 4, wherein said zirconia toughened molybdenum disilicide is prepared by the following method: mixing and ball-milling the molybdenum disilicide and the zirconium oxide according to the mass ratio of 7:1-3 for 2-3h, and then preserving the heat for 20-30min under the conditions of the temperature of 1200-1300 ℃, the pressure of 45-50MPa and the vacuum degree of 3-4 Pa.

6. The high-strength impervious foam concrete according to claim 1, wherein the fiber mixture comprises polypropylene fibers and carbon fibers in a mass ratio of 1: 0.8-1.2.

7. The high-strength impervious foam concrete according to claim 1, wherein the foam stabilizer is cellulose ether, triethanolamine and sodium dodecyl sulfate in a mass ratio of 1:0.7-1: 0.9-1.

8. The method for preparing a high strength impervious foam concrete according to any one of claims 1 to 7, comprising the steps of:

diluting a foaming agent and water according to a certain proportion to prepare a foaming agent solution, adding a foam stabilizer, and uniformly mixing to prepare foam;