An anti-freezing and heat-insulating concrete and its preparation method

Abstract

The present invention discloses an anti-freezing and heat-insulating concrete and a preparation method thereof, belonging to the technical field of building materials. The concrete of the present invention comprises the following raw materials in parts by weight: 150 - 200 parts of cement, 90 - 110 parts of fly ash, 50 - 70 parts of silica fume, 12 - 18 parts of a composite foaming agent, 200 - 300 parts of coarse aggregate, 100 - 200 parts of river sand, 30 - 50 parts of fiber, 2 - 5 parts of a water reducer, and 100 - 120 parts of water. The lightweight heat-insulating concrete prepared by using the composite foaming agent of the present invention has a uniform pore structure, good mechanical properties, a low heat-insulating coefficient, and good anti-corrosion properties, and the comprehensive performance of the concrete is excellent. At the same time, waste animal feathers are effectively utilized, which can not only save resources but also protect the environment, and the economic and social benefits are remarkable.

Description

Technical Field

[0001] The present invention belongs to the technical field of lightweight concrete, and particularly relates to a frost-resistant and heat-insulating concrete and a preparation method thereof. Background Art

[0002] At present, flammable materials such as polystyrene foam board, extruded board, and polyurethane account for a large proportion of the entire thermal insulation material market. These organic thermal insulation materials generally have the advantages of low bulk density, good thermal insulation performance, simple construction operation, and small water absorption rate, and can achieve good thermal insulation effects when used in building exterior walls. However, they also have undeniable defects, such as being flammable, easy to age, and poor durability. In a fire, organic materials will rapidly melt, generating a large amount of toxic gases and smoke. Moreover, organic thermal insulation materials cannot have the same service life as buildings and need to be replaced multiple times during the service life of the building, which not only wastes a large amount of manpower, financial resources, and material resources, but also brings environmental disasters such as white pollution caused by material replacement. Therefore, it is an inevitable trend of historical development and scientific and technological progress to replace organic thermal insulation materials with inorganic thermal insulation materials for building thermal insulation.

[0003] Among the existing inorganic thermal insulation materials, the prices of foam glass, foam aluminum, and foam ceramics are high and lack competitive advantages; while fiber thermal insulation materials such as rock wool and mineral wool have slightly lower prices but are harmful to physical health; moreover, they are not hard block materials and are difficult to apply. The construction period of rock wool factories is long, and it takes about 2 years from the establishment of the factory to production. At present, the supply of rock wool in the market also cannot meet the usage requirements, which determines that they will not become the main materials for building thermal insulation; granular loose thermal insulation materials such as expanded perlite and expanded vermiculite have high water absorption rates, the products are not frost-resistant and thaw-resistant, and are loose and not easy to use, so they are also restricted in application. Foamed concrete has easily available raw materials and low prices. It can not only achieve rapid cast-in-place construction and be made into various products, but also has excellent fire resistance, sound insulation, earthquake resistance, and weather resistance. It is the most suitable material to replace organic foam plastics.

[0004] Foamed concrete thermal insulation material is a porous concrete material containing a large number of closed pores inside, which is formed by introducing an appropriate amount of tiny air bubbles into cement slurry or cement mortar, stirring evenly, and then pouring and hardening. Due to the large number of air bubbles inside, foamed concrete has special properties such as light weight, heat insulation, sound insulation, etc. compared with ordinary concrete; in addition, foamed concrete also has a lower elastic modulus, good stress dispersion, and shock absorption performance, so it can be competent for some occasions with special performance requirements and meet the needs of modern construction projects.

[0005] However, there are still many problems with the current foam concrete materials in terms of thermal insulation performance. When the current foam concrete is not properly cured in the early stage or the water retention measures are insufficient, it is prone to shrinkage and cracking, which will affect its thermal insulation effect. The poor pore structure inside the foam concrete makes it easy to cause volume shrinkage and surface cracking when the water evaporates, and its mechanical properties are not good. At the same time, there are problems with poor erosion and freeze-thaw resistance.

[0006] Therefore, how to develop a lightweight foam thermal insulation concrete with excellent comprehensive performance is a technical problem that needs to be solved urgently at present. Summary of the Invention

[0007] In view of the problems existing in the prior art,

[0008] To achieve the above technical objectives, the technical solutions adopted by the present invention are as follows:

[0009] An anti-freeze thermal insulation concrete, comprising the following raw materials in parts by weight: 150 - 200 parts of cement, 90 - 110 parts of fly ash, 50 - 70 parts of silica fume, 12 - 18 parts of composite foaming agent, 200 - 300 parts of coarse aggregate, 100 - 200 parts of river sand, 30 - 50 parts of fiber, 2 - 5 parts of water reducing agent, and 100 - 120 parts of water.

[0010] Further, the cement is P·O42.5 ordinary Portland cement.

[0011] Further, the fly ash is Class I fly ash, and the specific surface area of the fly ash is 400 - 500m ,

[0014] , ,

[0013] , 2 , ,

[0012] , ,

[0011] ,

[0015] , / kg.

[0012] Further, the preparation method of the composite foaming agent is as follows:

[0013] A. Place 10g of waste animal feathers in a container, add 10mL of NaHSO3 solution with a mass concentration of 0.5 - 1%, then add 500mL of water and soak for 5 - 8h. Then add 50mL of calcium hydroxide with a mass concentration of 3%, heat up to 90 - 95°C, adjust the pH value to 10 - 11, and stir and react for 2h; after cooling, filter and adjust the pH to 7 - 8, and centrifuge to filter out the waste residue to obtain a clear feather protein solution;

[0014] B. Add 15g of glucose, 15g of tryptone, and 6g of yeast extract powder to 100 - 120mL of distilled water and stir evenly. After high-temperature sterilization, obtain a nutrient solution, inoculate EM bacteria, and then put the mixed solution into a constant-temperature shaking incubator and cultivate for 48h to obtain an EM bacteria foaming agent;

[0015] C. Mix the feather protein solution and the EM bacteria foaming agent in a volume ratio of 1:1, then add 5% sodium dodecyl sulfate and 3% polyoxyethylene sorbitan fatty acid ester based on the volume of the mixed solution, and stir with a stirrer at room temperature for more than 12 hours to prepare a composite foaming agent.

[0016] Further, the addition amount of EM bacteria in step B is 1-1.5% of the mass of the nutrient solution, and the effective viable bacteria count of the EM bacteria is not less than 20 billion / g. The EM bacteria can be commercially available products that meet the requirements. In the examples of the present invention, the EM bacteria are purchased from Jinan Hore Biotechnology Co., Ltd., model EM-01.

[0017] Further, the feathers used in step A are preferably from poultry with a large source, such as chickens, ducks, geese, pigeons and other poultry.

[0018] Further, the coarse aggregate is limestone gravel with a particle size of 5mm-25mm.

[0019] Further, the fiber is a polymer fiber, which is one or several of polypropylene fiber or polyacrylonitrile fiber.

[0020] Further, the water reducing agent is at least one of polycarboxylate water reducing agent, naphthalene series and fatty acid series water reducing agent.

[0021] A preparation method of antifreeze and heat-insulating concrete includes the following preparation steps:

[0022] (1) Prepare a composite foaming agent;

[0023] (2) Dilute the composite foaming agent and water in a mass ratio of 1:50-60 to prepare a foaming agent solution, and then use a foaming machine to prepare foam;

[0024] (3) Mix cement, fly ash, silica fume, coarse aggregate, river sand, and fiber evenly, then add a water reducing agent and water, and then add the foam prepared in step (2), mix and stir, pour and mold, and place the molded test block in a standard curing room for curing and demolding to obtain the final product concrete.

[0025] For traditional protein-based foaming agents, the foam stability is poor, and it is easy to break or lose stability during use. The prepared concrete structure is uneven, and its strength and heat-insulating performance cannot meet the actual use requirements. At the same time, animal protein-based foaming agents rely on raw materials such as animal keratin, and these raw materials have limited sources and high prices, which restricts their large-scale development and application. In addition, although plant protein-based foaming agents have wide raw material sources and low costs, their development is relatively lagging behind, and there are problems such as low foaming ability and poor anti-corrosion performance, making it difficult to meet the requirements of large-scale industrial applications.

[0026] Generally, common chemical foaming agents, such as rosin soap and rosin thermopolymer, although having good compatibility, require heat treatment, and their foam stability is average, and sedimentation is likely to occur. The use of chemical foaming agents may bring potential safety hazards and environmental problems.

[0027] Therefore, in the present invention, discarded poultry feathers are selected as raw materials. Animal feathers are rich in keratin, and treatment with NaHSO3 can open more disulfide bonds between protein molecules, improving the hydrolysis rate of keratin. The prepared animal protein-based foaming agent has good foam stability and foaming ability, and is especially suitable for producing ultra-low density foam concrete products. The obtained concrete has a low density, and the pores are closed and independent, with excellent impermeability and heat insulation performance.

[0028] Meanwhile, a microbial foaming agent is prepared by fermenting with EM bacteria. The microbial foaming agent generates carbon dioxide through fermentation to form a foam structure, thereby improving the microstructure of the concrete. After being used in equal proportion with the animal protein foaming agent, the obtained foam is more uniform and delicate, with better stability. After being added to the concrete, it can form a more uniform pore structure, and the bubbles are closed and independent. Macroscopically, the concrete shows excellent impermeability and heat insulation performance. At the same time, EM bacteria can accelerate the hydration reaction of the concrete, reduce water loss, and form a self-curing environment, thereby improving the corrosion resistance and durability of the concrete.

[0029] Adding polymer fibers, such as polypropylene and polyacrylonitrile fibers, can significantly increase the air content of the concrete, which helps to capture air and form a more uniform pore structure, splitting the large pores and through holes in the concrete into smaller and more uniform small pores. On the one hand, it helps to improve the sulfate erosion resistance and acid corrosion resistance of the concrete, and on the other hand, it helps to enhance the heat insulation performance of the concrete.

[0030] Beneficial effects:

[0031] The lightweight heat-insulating concrete prepared by using the composite foaming agent of the present invention has a uniform pore structure, good mechanical properties, a low heat insulation coefficient, and good erosion resistance, and the comprehensive performance of the concrete is excellent. At the same time, the discarded animal feathers are effectively utilized, which can not only save resources but also protect the environment, with remarkable economic and social benefits. Description of the drawings

[0032] Figure 1 It is a photo of the deterioration of the appearance of the heat-insulating concrete after 80 freeze-thaw cycles of the specimen in Example 1;

[0033] Figure 2 It is a photo of the deterioration of the appearance of the heat-insulating concrete after 80 freeze-thaw cycles of the specimens in Comparative Examples 1-3;

[0034] Figure 3Photos showing the deterioration of the appearance of the insulating concrete after 80 freeze-thaw cycles for the specimens of Comparative Examples 4-6;

[0035] Figure 4 Internal pore structure diagram of the specimen of Example 1;

[0036] Figure 5 Internal pore structure diagrams of the specimens of Comparative Examples 1-6. Specific implementation manners

[0037] The technical solution of the present invention will be further described below in conjunction with specific embodiments, but not limited thereto.

[0038] Example 1

[0039] An anti-freezing and heat-insulating concrete, comprising the following raw materials in parts by weight: 150 parts of cement, 90 parts of fly ash, 50 parts of silica fume, 12 parts of composite foaming agent, 200 parts of coarse aggregate, 200 parts of river sand, 30 parts of fiber, 2 parts of water reducing agent, and 120 parts of water.

[0040] The cement is P·O42.5 ordinary Portland cement.

[0041] The fly ash is Class I fly ash, and the specific surface area of the fly ash is 400-500 m 2 / kg.

[0042] The preparation method of the composite foaming agent is as follows:

[0043] A. Place 10 g of waste animal feathers in a container, add 10 mL of a NaHSO3 solution with a mass concentration of 0.5%, then add 500 mL of water and soak for 5 h, then add 50 mL of calcium hydroxide with a mass concentration of 3%, raise the temperature to 90-95 °C, adjust the pH value to 10-11, and stir and react for 2 h; after cooling, filter and adjust the pH to 7-8, and centrifuge to filter out the waste residue to obtain a clear feather protein solution;

[0044] B. Add 15 g of glucose, 15 g of tryptone, and 6 g of yeast extract powder to 100 mL of distilled water and stir evenly. After high-temperature sterilization, obtain a nutrient solution, inoculate EM bacteria, and then place the mixed solution in a constant-temperature shaking incubator and culture for 48 h to obtain an EM bacteria foaming agent;

[0045] C. Mix the feather protein solution and the EM bacteria foaming agent according to a volume ratio of 1:1, add 5% sodium dodecyl sulfate and 3% polyoxyethylene sorbitan fatty acid ester based on the volume of the mixed solution, and use a stirrer to stir at room temperature for more than 12 h to prepare a composite foaming agent.

[0046] In step B, the addition amount of EM bacteria is 1% of the mass of the nutrient solution, and the effective viable count of the EM bacteria is not less than 20 billion / g. The EM bacteria can be purchased from commercially available products that meet the requirements. In this example, the EM bacteria are purchased from Jinan Herui Biotechnology Co., Ltd., and the model is EM-01.

[0047] The feathers used in step A are preferably from poultry with a large source, such as chicken, duck, goose, pigeon and other poultry.

[0048] The coarse aggregate is limestone gravel with a particle size of 5 mm - 25 mm.

[0049] The fiber is a polymer fiber, which is a polypropylene fiber.

[0050] The water reducing agent is a polycarboxylate water reducing agent.

[0051] A preparation method of antifreeze and heat-insulating concrete includes the following preparation steps:

[0052] (1) Prepare a composite foaming agent;

[0053] (2) Dilute the composite foaming agent and water according to a mass ratio of 1:50 to prepare a foaming agent solution, and then use a foaming machine to prepare foam;

[0054] (3) Mix cement, fly ash, silica fume, coarse aggregate, river sand, and fiber evenly, then add a water reducing agent and water, and then add the foam prepared in step (2), mix and stir, pour and mold, and place the formed test block in a standard curing room for curing and demolding to obtain the final product concrete.

[0055] Example 2

[0056] An antifreeze and heat-insulating concrete includes the following raw materials in parts by weight: 200 parts of cement, 100 parts of fly ash, 70 parts of silica fume, 15 parts of composite foaming agent, 250 parts of coarse aggregate, 200 parts of river sand, 40 parts of fiber, 3 parts of water reducing agent, and 110 parts of water.

[0057] The cement is P·O42.5 ordinary Portland cement.

[0058] The fly ash is Class I fly ash, and the specific surface area of the fly ash is 400 - 500 m 2 / kg.

[0059] The preparation method of the composite foaming agent is:

[0060] A. Place 10 g of waste animal feathers in a container, add 10 mL of a 0.8% NaHSO3 solution by mass concentration, then add 500 mL of water and soak for 6 h. Then add 50 mL of a 3% calcium hydroxide solution, raise the temperature to 90 - 95 °C, adjust the pH value to 10 - 11, and stir and react for 2 h. After cooling, filter and adjust the pH to 7 - 8, and centrifuge to filter out the waste residue to obtain a clear feather protein solution;

[0061] B. Add 15 g of glucose, 15 g of tryptone, and 6 g of yeast extract powder to 120 mL of distilled water, stir evenly, sterilize at high temperature to obtain a nutrient solution, inoculate EM bacteria, and then place the mixed solution in a constant temperature shaking incubator and culture for 48 h to obtain an EM bacteria foaming agent;

[0062] C. After mixing the feather protein solution and the EM bacteria foaming agent at a volume ratio of 1:1, add 5% sodium dodecyl sulfate and 3% polyoxyethylene sorbitan fatty acid ester based on the volume of the mixed solution, and use a stirrer to stir at room temperature for more than 12 h to prepare a composite foaming agent.

[0063] In step B, the addition amount of EM bacteria is 1% of the mass of the nutrient solution, and the effective viable count of the EM bacteria is not less than 20 billion / g. The EM bacteria can be a commercially available product that meets the requirements. In this example, the EM bacteria are purchased from Jinan Hore Biotechnology Co., Ltd., model EM - 01.

[0064] The feathers used in step A are preferably from poultry with a large source, such as poultry like chickens, ducks, geese, pigeons, etc.

[0065] The coarse aggregate is limestone crushed stone with a particle size of 5 mm - 25 mm.

[0066] The fiber is polyacrylonitrile fiber.

[0067] The water - reducing agent is a naphthalene - based water - reducing agent.

[0068] A preparation method of frost - resistant and heat - insulating concrete includes the following preparation steps:

[0069] (1) Prepare a composite foaming agent;

[0070] (2) Dilute the composite foaming agent and water at a mass ratio of 1:60 to prepare a foaming agent solution, and then use a foaming machine to prepare foam;

[0071] (3) Mix cement, fly ash, silica fume, coarse aggregate, river sand, and fiber evenly, then add a water - reducing agent and water, and then add the foam prepared in step (2), mix and stir, pour and mold, and place the molded test block in a standard curing room for curing and demolding to obtain the final product concrete.

[0072] Example 3

[0073] An anti-freezing and heat-insulating concrete, comprising the following raw materials in parts by weight: 180 parts of cement, 100 parts of fly ash, 60 parts of silica fume, 15 parts of composite foaming agent, 250 parts of coarse aggregate, 150 parts of river sand, 50 parts of fiber, 4 parts of water reducing agent, and 100 parts of water.

[0074] The cement is P·O42.5 ordinary Portland cement.

[0075] The fly ash is Class I fly ash, and the specific surface area of the fly ash is 400 - 500 m 2 / kg.

[0076] The preparation method of the composite foaming agent is as follows:

[0077] A. Place 10 g of waste animal feathers in a container, add 10 mL of a NaHSO3 solution with a mass concentration of 0.5%, then add 500 mL of water and soak for 8 h. Then add 50 mL of calcium hydroxide with a mass concentration of 3%, heat up to 90 - 95 °C, adjust the pH value to 10 - 11, and stir and react for 2 h; after cooling, filter and adjust the pH to 7 - 8, and centrifuge to filter out the waste residue to obtain a clear feather protein solution;

[0078] B. Add 15 g of glucose, 15 g of tryptone, and 6 g of yeast extract powder to 120 mL of distilled water, stir evenly, sterilize at high temperature to obtain a nutrient solution, inoculate EM bacteria, and then place the mixed solution in a constant temperature shaking incubator and culture for 48 h to obtain an EM bacteria foaming agent;

[0079] C. Mix the feather protein solution and the EM bacteria foaming agent according to a volume ratio of 1:1, add 5% of sodium dodecyl sulfate and 3% of polyoxyethylene sorbitan fatty acid ester based on the volume of the mixed solution, and use a stirrer to stir at room temperature for more than 12 h to prepare a composite foaming agent.

[0080] Further, the addition amount of EM bacteria in step B is 1% of the mass of the nutrient solution, and the effective viable count of the EM bacteria is not less than 20 billion / g. The EM bacteria can be a commercially available product that meets the requirements. In this example, the EM bacteria are purchased from Jinan Hore Biotechnology Co., Ltd., model EM - 01.

[0081] The feathers used in step A are preferably from poultry with a large source, such as poultry like chickens, ducks, geese, pigeons, etc.

[0082] The coarse aggregate is limestone gravel with a particle size of 5 mm - 25 mm.

[0083] The fiber is a polymer fiber, which is one or several of polypropylene fiber or polyacrylonitrile fiber.

[0084] The water reducing agent is a polycarboxylate water reducing agent.

[0085] A preparation method of antifreeze and heat-insulating concrete, comprising the following preparation steps:

[0086] (1) Prepare a composite foaming agent;

[0087] (2) Dilute the composite foaming agent and water according to a mass ratio of 1:55 to prepare a foaming agent solution, and then use a foaming machine to prepare foam;

[0088] (3) Mix cement, fly ash, silica fume, coarse aggregate, river sand, and fiber evenly, then add a water reducing agent and water, and then add the foam prepared in step (2). Mix and stir, pour and mold, and place the molded test block in a standard curing room for curing and demolding to obtain the final product concrete.

[0089] Example 4

[0090] An antifreeze and heat-insulating concrete, comprising the following raw materials in parts by weight: 200 parts of cement, 110 parts of fly ash, 70 parts of silica fume, 18 parts of composite foaming agent, 300 parts of coarse aggregate, 100 parts of river sand, 50 parts of fiber, 5 parts of water reducing agent, and 100 parts of water.

[0091] The cement is P·O42.5 ordinary Portland cement.

[0092] The fly ash is Class I fly ash, and the specific surface area of the fly ash is 400-500m 2 / kg.

[0093] The preparation method of the composite foaming agent is as follows:

[0094] A. Place 10 g of waste animal feathers in a container, add 10 mL of a 1% NaHSO3 solution by mass concentration, then add 500 mL of water and soak for 8 h, then add 50 mL of a 3% calcium hydroxide, heat up to 90-95 °C, adjust the pH value to 10-11, and stir and react for 2 h; after cooling, filter and adjust the pH to 7-8, and centrifuge to filter out the waste residue to obtain a clear feather protein solution;

[0095] B. Add 15 g of glucose, 15 g of tryptone, and 6 g of yeast extract powder to 100 mL of distilled water, stir evenly, sterilize at high temperature to obtain a nutrient solution, inoculate EM bacteria, and then place the mixed solution in a constant temperature shaking incubator and culture for 48 h to obtain an EM bacteria foaming agent;

[0096] C. Mix the feather protein solution and the EM bacteria foaming agent according to a volume ratio of 1:1, then add 5% sodium dodecyl sulfate and 3% polyoxyethylene sorbitan fatty acid ester of the volume of the mixed solution, and use a stirrer to stir at room temperature for more than 12 h to prepare a composite foaming agent.

[0097] In step B, the addition amount of EM bacteria is 1.5% of the mass of the nutrient solution, and the effective viable count of the EM bacteria is not less than 20 billion / g. The EM bacteria can be commercially available products that meet the requirements. In this example, the EM bacteria are purchased from Jinan Hore Biotechnology Co., Ltd., model EM-01.

[0098] The feathers used in step A are preferably from poultry with a large source, such as chickens, ducks, geese, pigeons and other poultry.

[0099] The coarse aggregate is limestone gravel with a particle size of 5mm - 25mm.

[0100] The fiber is a polymer fiber. [[ID=IO]]

[0101] The water reducing agent is a polycarboxylate water reducing agent.

[0102] A preparation method of freeze-resistant and heat-insulating concrete includes the following preparation steps:

[0103] (1) Prepare a composite foaming agent;

[0104] (2) Dilute the composite foaming agent and water according to a mass ratio of 1:50 to prepare a foaming agent solution, and then use a foaming machine to prepare foam;

[0105] (3) Mix cement, fly ash, silica fume, coarse aggregate, river sand, and fiber evenly, then add a water reducing agent and water, and then add the foam prepared in step (2), mix and stir, pour and mold, and place the molded test block in a standard curing room for curing and demolding to obtain the final product concrete.

[0106] Comparative Example 1

[0107] A freeze-resistant and heat-insulating concrete includes the following raw materials in parts by weight: 150 parts of cement, 90 parts of fly ash, 50 parts of silica fume, 12 parts of foaming agent, 200 parts of coarse aggregate, 200 parts of river sand, 30 parts of fiber, 2 parts of water reducing agent, and 120 parts of water.

[0108] The preparation method of the foaming agent is as follows:

[0109] A. Place 10g of waste animal feathers in a container, add 10mL of a 0.5% NaHSO3 solution by mass concentration, then add 500mL of water and soak for 5h, then add 50mL of a 3% calcium hydroxide by mass concentration, heat up to 90 - 95°C, adjust the pH value to 10 - 11, and stir and react for 2h; after cooling, filter and adjust the pH to 7 - 8, and centrifuge to filter out the waste residue to obtain a clear feather protein solution;

[0110] B. Draw 5% of the volume of the feather protein solution of sodium dodecyl sulfate and 3% of polyoxyethylene sorbitan fatty acid ester, and use a stirrer to stir at room temperature for more than 12h to prepare a foaming agent.

[0111] In this comparative example, compared with Example 1, except that only feather protein is used as the raw material for the foaming agent, the other raw materials and preparation methods are the same as those in Example 1.

[0112] Comparative Example 2

[0113] An antifreeze and heat-insulating concrete comprises the following raw materials in parts by weight: 150 parts of cement, 90 parts of fly ash, 50 parts of silica fume, 12 parts of foaming agent, 200 parts of coarse aggregate, 200 parts of river sand, 30 parts of fiber, 2 parts of water reducing agent, and 120 parts of water.

[0114] The preparation method of the foaming agent is as follows:

[0115] A. Add 15 g of glucose, 15 g of tryptone and 6 g of yeast extract powder into 100 mL of distilled water, stir evenly, obtain a nutrient solution after high-temperature sterilization, inoculate EM bacteria, and then put the mixed solution into a constant temperature shaking incubator for culturing for 48 h to obtain an EM bacteria foaming agent;

[0116] B. Add the EM bacteria foaming agent, 5% of sodium dodecyl sulfate and 3% of polyoxyethylene sorbitan fatty acid ester based on its volume, and use a stirrer to stir at room temperature for more than 12 h to prepare a foaming agent.

[0117] In this comparative example, compared with Example 1, except that only the EM bacteria foaming agent is used as the foaming agent, the other raw materials and preparation methods are the same as those in Example 1.

[0118] Comparative Example 3

[0119] An antifreeze and heat-insulating concrete comprises the following raw materials in parts by weight: 150 parts of cement, 90 parts of fly ash, 50 parts of silica fume, 12 parts of composite foaming agent, 200 parts of coarse aggregate, 200 parts of river sand, 30 parts of fiber, 2 parts of water reducing agent, and 120 parts of water.

[0120] The cement is P·O42.5 ordinary Portland cement.

[0121] The fly ash is Class I fly ash, and the specific surface area of the fly ash is 400 - 500 m 2 / kg.

[0122] The preparation method of the composite foaming agent is as follows:

[0123] A. Place 10 g of waste animal feathers in a container, add 10 mL of a 0.5% NaHSO3 solution by mass concentration, then add 500 mL of water and soak for 5 h, then add 50 mL of a 3% calcium hydroxide by mass concentration, heat up to 90 - 95 °C, adjust the pH value to 10 - 11, and stir and react for 2 h; after cooling, filter and adjust the pH to 7 - 8, and centrifuge to filter out the waste residue to obtain a clear feather protein solution;

[0124] B. Add 15 g of glucose, 15 g of tryptone, and 6 g of yeast extract powder to 100 mL of distilled water, stir evenly, obtain a nutrient solution after high-temperature sterilization, inoculate EM bacteria, and then place the mixture in a constant-temperature shaking incubator for 48 h to obtain an EM bacteria foaming agent;

[0125] C. After mixing the feather protein solution and the EM bacteria foaming agent in a volume ratio of 1:1, add polyoxyethylene sorbitan fatty acid ester accounting for 3% of the volume of the mixture, and use a stirrer to stir at room temperature for more than 12 h to prepare a composite foaming agent.

[0126] In this comparative example, except for not adding sodium dodecyl sulfate in the preparation method of the composite foaming agent, the other raw materials and preparation methods are the same as those in Example 1.

[0127] Comparative Example 4

[0128] An antifreeze and heat-insulating concrete includes the following raw materials in parts by weight: 150 parts of cement, 90 parts of fly ash, 50 parts of silica fume, 12 parts of composite foaming agent, 200 parts of coarse aggregate, 200 parts of river sand, 30 parts of fiber, 2 parts of water reducer, and 120 parts of water.

[0129] The cement is P·O42.5 ordinary Portland cement.

[0130] The fly ash is Class I fly ash, and the specific surface area of the fly ash is 400 - 500 m 2 / kg.

[0131] The preparation method of the composite foaming agent is as follows:

[0132] A. Place 10 g of waste animal feathers in a container, add 10 mL of a NaHSO3 solution with a mass concentration of 0.5%, then add 500 mL of water and soak for 5 h, then add 50 mL of calcium hydroxide with a mass concentration of 3%, raise the temperature to 90 - 95 °C, adjust the pH value to 10 - 11, and stir and react for 2 h; after cooling, filter and adjust the pH to 7 - 8, and centrifuge to filter out the waste residue to obtain a clear feather protein solution;

[0133] B. Add 15 g of glucose, 15 g of tryptone, and 6 g of yeast extract powder to 100 mL of distilled water, stir evenly, obtain a nutrient solution after high-temperature sterilization, inoculate EM bacteria, and then place the mixture in a constant-temperature shaking incubator for 48 h to obtain an EM bacteria foaming agent;

[0134] C. After mixing the feather protein solution and the EM bacteria foaming agent in a volume ratio of 1:1, add sodium dodecyl sulfate accounting for 5% of the volume of the mixture, and use a stirrer to stir at room temperature for more than 12 h to prepare a composite foaming agent.

[0135] In this comparative example, except for not adding polyoxyethylene sorbitan fatty acid ester in the preparation method of the composite foaming agent, the other raw materials and the preparation method are the same as those in Example 1.

[0136] Comparative Example 5

[0137] An anti-freezing and heat-insulating concrete comprises the following raw materials in parts by weight: 150 parts of cement, 90 parts of fly ash, 50 parts of silica fume, 12 parts of composite foaming agent, 200 parts of coarse aggregate, 200 parts of river sand, 30 parts of fiber, 2 parts of water reducing agent, and 120 parts of water.

[0138] The cement is P·O42.5 ordinary Portland cement.

[0139] The fly ash is Class I fly ash, and the specific surface area of the fly ash is 400 - 500 m 2 / kg.

[0140] The preparation method of the composite foaming agent is as follows:

[0141] A. Put 10 g of waste animal feathers into a container, add 10 mL of a NaHSO3 solution with a mass concentration of 0.5%, then add 500 mL of water and soak for 5 h. Then add 50 mL of calcium hydroxide with a mass concentration of 3%, raise the temperature to 90 - 95 °C, adjust the pH value to 10 - 11, and stir and react for 2 h; after cooling, filter and adjust the pH to 7 - 8, and centrifuge to filter out the waste residue to obtain a clear feather protein solution;

[0142] B. Add 15 g of glucose, 15 g of tryptone, and 6 g of yeast extract powder to 100 mL of distilled water, stir evenly, sterilize at high temperature to obtain a nutrient solution, inoculate EM bacteria, and then put the mixed solution into a constant temperature shaking incubator and culture for 48 h to obtain an EM bacteria foaming agent;

[0143] C. Mix the feather protein solution and the EM bacteria foaming agent according to a volume ratio of 2:1, add 5% of sodium dodecyl sulfate and 3% of polyoxyethylene sorbitan fatty acid ester based on the volume of the mixed solution, and use a stirrer to stir at room temperature for more than 12 h to prepare a composite foaming agent.

[0144] In this comparative example, except for changing the volume ratio of the feather protein solution to the EM bacteria foaming agent to 2:1 in the preparation method of the composite foaming agent, the other raw materials and the preparation method are the same as those in Example 1.

[0145] Comparative Example 6

[0146] An anti-freezing and heat-insulating concrete comprises the following raw materials in parts by weight: 150 parts of cement, 90 parts of fly ash, 50 parts of silica fume, 12 parts of composite foaming agent, 200 parts of coarse aggregate, 200 parts of river sand, 30 parts of fiber, 2 parts of water reducing agent, and 120 parts of water.

[0147] The cement is P·O42.5 ordinary Portland cement.

[0148] The fly ash is Class I fly ash, and the specific surface area of the fly ash is 400 - 500 m 2 / kg.

[0149] The preparation method of the composite foaming agent is as follows:

[0150] A. Place 10 g of waste animal feathers in a container, add 10 mL of a NaHSO3 solution with a mass concentration of 0.5%, then add 500 mL of water and soak for 5 h. Then add 50 mL of calcium hydroxide with a mass concentration of 3%, heat up to 90 - 95 °C, adjust the pH value to 10 - 11, and stir and react for 2 h; after cooling, filter and adjust the pH to 7 - 8, and centrifuge to filter out the waste residue to obtain a clear feather protein solution;

[0151] B. Add 15 g of glucose, 15 g of tryptone, and 6 g of yeast extract powder to 100 mL of distilled water, stir evenly, sterilize at high temperature to obtain a nutrient solution, inoculate EM bacteria, and then place the mixed solution in a constant temperature shaking incubator and culture for 48 h to obtain an EM bacteria foaming agent;

[0152] C. Mix the feather protein solution and the EM bacteria foaming agent according to a volume ratio of 1:2, add 5% sodium dodecyl sulfate and 3% polyoxyethylene sorbitan fatty acid ester based on the volume of the mixed solution, and use a stirrer to stir at room temperature for more than 12 h to prepare a composite foaming agent.

[0153] In this comparative example, except that the volume ratio of the feather protein solution to the EM bacteria foaming agent in the preparation method of the composite foaming agent is changed to 1:2, the other raw materials and preparation methods are the same as those in Example 1.

[0154] Performance test

[0155] Foam properties:

[0156] Perform performance tests on the composite foaming agent or the foaming agent components prepared in the examples and comparative examples of the present invention. Refer to JC / T2199—2013 "Foaming Agent for Foamed Concrete" to test the foaming multiple of the foaming agent solution, the 1 h settlement distance of the prepared foam, and the 1 h bleeding rate respectively.

[0157] Table 1 Comparison of foaming performance of examples and comparative examples

[0158] Foaming multiple 1h sedimentation distance / mm 1h bleeding rate / mL Foam stability / h Example 1 30 2.2 65.2 10.5 Comparative example 1 25 8.5 75.1 5.5 Comparative example 2 24 7.9 73.2 5.3 Comparative example 3 26 7.0 70.5 5.0 Comparative example 4 27 6.5 70.0 5.0 Comparative example 5 28 4.0 68.5 6.5 Comparative example 6 30 3.5 67.0 7.0 Standard requirements ＞20 ＜10 ＜80 ≥2

[0159] From the data in Table 1, we can see that the composite foaming agent prepared in Example 1 of the present invention has good foaming performance. The feather protein solution and the microbial foaming agent interact with each other, and after being mixed in equal proportions, they exhibit good foaming and foam-stabilizing performance, and the bubble performance is good.

[0160] Concrete property test:

[0161] Specimen: Pour the slurries of the concretes prepared in Examples 1-4 and Comparative Examples 1-6 into a mold with dimensions of 100 mm×100 mm×100 mm. Demold after molding for 24 h, and place the demolded specimens in a standard curing box at a temperature of (20±2)°C and a relative humidity >95% for 28 d;

[0162] Pore structure: Vertically cut the molded specimen, and then use a grinding machine to grind the cross-section flat. To prevent the pores from being blocked by the cement powder generated during grinding, oscillate and wash the ground specimen in an ultrasonic wave, and obtain a cross-section with obvious pore structure after drying. Use a VHX-600K type ultra-depth-of-field microscope to construct a three-dimensional image of the cross-section for observation.

[0163] Test the foamed concrete specimens in accordance with JG / T266-2011 "Foamed Concrete". Use an AG-X type Shimadzu electronic universal testing machine to measure the compressive strength of the specimens cured to the age. There are 3 specimens in each group, and the results are averaged.

[0164] Use a thermal conductivity meter DRRPL-3B to test the thermal conductivity of the sample; test the chloride ion penetration resistance of the concrete according to the rapid chloride ion migration coefficient method (RCM method) in GB / T50082-2009 "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete".

[0165] Refer to GB / T50082-2009 to design a freeze-thaw cycle test, and complete the test using a high and low temperature alternating humidity chamber. Freeze for 8 h in an environment of (-19±4)°C and thaw for 4 h in an environment of (18±4)°C. A total of 12 h is one cycle, and the number of cycles is 40 and 80 times. During the test, ensure that the central freezing temperature of the specimen is greater than -10°C, and the time taken to heat up from -20°C to 20°C is not more than 1.5 h. And test the mass loss.

[0166] Table 2 Test results of comprehensive properties of concrete

[0167]

[0168] From the data in the table, we can see that the concrete specimens of the embodiments of the present invention have good frost resistance and erosion resistance, and at the same time have a low thermal conductivity and good heat preservation performance. From the physical photos ( Figures 1-3 ) and the pore structure diagrams ( Figures 4-5)It can also be seen that after 80 cycles of the specimen in Embodiment 1 of the present invention, the surface is flat and there are no obvious exfoliates, and the pore structure is uniform and dense. For Comparative Examples 1-6 with the blowing agent composition changed, different degrees of exfoliation phenomena occur, and there are also many through holes and large pore structures inside. This is because the change in the blowing agent composition makes the pore structure and surface structure inside the concrete uneven, resulting in uneven temperature conduction, and the concrete macroscopically shows a decline in comprehensive abilities such as frost resistance and erosion resistance.

[0169] It should be noted that the above embodiments are only some of the preferred embodiments for implementing the present invention, rather than all embodiments. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

Claims

1. An anti-freezing and heat-insulating concrete, characterized in that, It comprises the following raw materials in parts by weight: 150 - 200 parts of cement, 90 - 110 parts of fly ash, 50 - 70 parts of silica fume, 12 - 18 parts of composite foaming agent, 200 - 300 parts of coarse aggregate, 100 - 200 parts of river sand, 30 - 50 parts of fiber, 2 - 5 parts of water reducing agent, and 100 - 120 parts of water; The preparation method of the composite foaming agent is as follows: A. Put 10 g of waste animal feathers into a container, add 10 mL of NaHSO3 solution with a mass concentration of 0.5 - 1%, then add 500 mL of water and soak for 5 - 8 h. Then add 50 mL of calcium hydroxide with a mass concentration of 3%, heat up to 90 - 95 °C, adjust the pH value to 10 - 11, and stir and react for 2 h. After cooling, filter and adjust the pH to 7 - 8, and centrifuge to filter out the waste residue to obtain a clear feather protein solution; B. Add 15 g of glucose, 15 g of tryptone, and 6 g of yeast extract powder to 100 - 120 mL of distilled water and stir evenly. After high-temperature sterilization, obtain a nutrient solution, inoculate EM bacteria, and then put the nutrient solution inoculated with EM bacteria into a constant temperature shaking incubator and culture for 48 h to obtain an EM bacteria foaming agent; C. Mix the feather protein solution and the EM bacteria foaming agent in a volume ratio of 1:1, add 5% of sodium dodecyl sulfate and 3% of polyoxyethylene sorbitan fatty acid ester based on the volume of the mixed solution, and use a stirrer to stir at room temperature for more than 12 h to prepare a composite foaming agent.

2. The anti-freezing and heat-insulating concrete according to claim 1, wherein The cement is P·O42.5 ordinary Portland cement.

3. The anti-freezing and heat-insulating concrete according to claim 1, wherein, The fly ash is Class I fly ash, and the specific surface area of the fly ash is 400 - 500 m 2 / kg.

4. The anti-freezing and heat-insulating concrete according to claim 1, characterized in that, In step B, the addition amount of EM bacteria is 1 - 1.5% of the mass of the nutrient solution, and the effective viable count of the EM bacteria is not less than 20 billion / g.

5. The anti-freezing and heat-insulating concrete according to claim 1, wherein The coarse aggregate is limestone gravel with a particle size of 5 mm - 25 mm.

6. The heat-insulating concrete according to claim 1, wherein, The fiber is one or several of polypropylene fiber or polyacrylonitrile fiber.

7. The anti-freezing and heat-insulating concrete according to claim 1, wherein The water reducing agent is at least one of polycarboxylate water reducing agent, naphthalene series and fatty acid series water reducing agents.

8. The preparation method of the antifreeze and heat-insulating concrete according to any one of claims 1-7, characterized in that, It includes the following preparation steps: (1) Prepare a composite foaming agent; (2) Dilute the composite foaming agent and water in a mass ratio of 1:50 - 60 to prepare a foaming agent solution, and then use a foaming machine to prepare foam; (3) Mix cement, fly ash, silica fume, coarse aggregate, river sand, and fiber evenly, then add a water reducing agent and water, and then add the foam prepared in step (2), mix and stir, pour and mold, and place the molded test block in a standard curing room for curing and demolding to obtain the final product concrete.

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