CN113603423A

CN113603423A - Foam concrete and preparation method thereof

Info

Publication number: CN113603423A
Application number: CN202110976373.2A
Authority: CN
Inventors: 高忠尧; 高加; 陈燕
Original assignee: Hangzhou Jinding Industrial Co ltd
Current assignee: Hangzhou Jinding Industrial Co ltd
Priority date: 2021-08-24
Filing date: 2021-08-24
Publication date: 2021-11-05

Abstract

The invention relates to the technical field of concrete, and particularly discloses foam concrete and a preparation method thereof, wherein the foam concrete comprises the following raw materials in parts by weight: 150-250 parts of cement, 20-30 parts of fly ash, 40-60 parts of mineral powder, 10-20 parts of silica fume, 10-30 parts of modified silica aerogel powder, 20-40 parts of reinforcing fiber, 5-8 parts of light mullite, 3-6 parts of foaming agent and 100 parts of water; the reinforced fiber comprises at least one of polyvinyl alcohol fiber, aluminum silicate fiber and basalt fiber; the preparation method comprises mixing modified silica aerogel powder, cement and water, and mixing to obtain a first mixture; mixing the first mixture with light mullite, mineral powder, silica fume and fly ash, and uniformly mixing to obtain a second mixture; mixing the second mixture with the reinforced fibers, adding a foaming agent after uniformly mixing, and uniformly mixing to obtain foam concrete; the foam concrete has the advantage of high strength.

Description

Foam concrete and preparation method thereof

Technical Field

The invention relates to the technical field of concrete, in particular to foam concrete and a preparation method thereof.

Background

The foam concrete, also called as air bubble concrete, is lightweight concrete containing a large amount of closed air holes, has good heat preservation and insulation effects, and is widely applied to the field of buildings.

Aerogel is a nano-porous material, usually composed of silica, with large porosity and low density, and is one of the most excellent thermal insulation materials in current use. Along with the development of the industry, people gradually add aerogel into foam concrete to prepare novel aerogel concrete, and the aerogel is endowed with good light weight and heat insulation effect.

Through the related technology, although the aerogel is light, the mechanical property of the aerogel is poor due to the large porosity, and the strength of the foam concrete prepared from the aerogel is low.

Disclosure of Invention

In order to improve the strength of the foam concrete, the application provides the foam concrete and a preparation method thereof.

In a first aspect, the present application provides a foamed concrete, which adopts the following technical scheme:

a foam concrete comprises the following raw materials in parts by weight:

150 portions of cement and 250 portions of cement;

20-30 parts of fly ash;

40-60 parts of mineral powder;

10-20 parts of silica fume;

10-30 parts of modified silicon dioxide aerogel powder;

20-40 parts of reinforcing fibers;

5-8 parts of light mullite;

3-6 parts of a foaming agent;

100 portions of water and 200 portions of water;

the reinforcing fiber comprises at least one of polyvinyl alcohol fiber, aluminum silicate fiber and basalt fiber.

By adopting the technical scheme, the modified silicon dioxide aerogel powder, the light mullite and the reinforcing fiber are added into the foam concrete, so that the foam concrete has good heat-insulating property and high strength. The silica aerogel powder is modified, the silica aerogel framework is wrapped to a certain degree, and the density of the modified silica aerogel powder is improved and the strength of the foam concrete is enhanced under the condition that the porosity of the foam concrete is slightly influenced. The reinforcing fiber is at least one of polyvinyl alcohol fiber, aluminum silicate fiber and basalt fiber, so that the strength of the foam concrete is enhanced together with the modified silicon dioxide aerogel powder. In addition, after the modified silica aerogel powder, the reinforcing fiber and the light mullite are matched, the compressive strength and the heat-insulating property of the foam concrete are enhanced together.

In conclusion, the compressive strength and the heat-insulating property of the foam concrete are enhanced by modifying the silicon dioxide aerogel powder and combining the silicon dioxide aerogel powder with the reinforcing fiber and the light mullite.

Preferably, the preparation method of the modified aerogel comprises the following steps:

a1, mixing the silicon dioxide aerogel powder with 40-70% ethanol solution by weight percent, and mixing and dispersing for 1-3h to obtain a silicon dioxide aerogel powder treated substance;

a2, mixing the silicon dioxide aerogel powder processed product with epoxy acrylate resin, a silane coupling agent and an initiator at the temperature of 72-80 ℃, mixing for 2.5-4h, and drying to obtain the modified silicon dioxide aerogel powder.

Through adopting above-mentioned technical scheme, at first adopt ethanol solution to dissolve silica aerogel powder for silica aerogel powder later stage fully reacts. And then generating an epoxy acrylate resin coating film on the surface of the gel skeleton ions through an initiator and a silane coupling agent, reinforcing and enhancing the gel skeleton, and enhancing the density of the gel skeleton ions under the condition of not influencing the porosity, thereby further enhancing the strength of the foam concrete. In addition, by improving the density of the modified silicon dioxide aerogel powder, the density difference is reduced in the process of mixing with other raw materials of the foam concrete, the modified silicon dioxide aerogel powder is also favorably and uniformly mixed with the raw materials of cement and the like, and the phase separation phenomenon is reduced, so that the compressive strength and the density of the foam concrete are improved.

Preferably, in the step A2, the weight percentage of the ethanol solution is 45-55%.

By adopting the technical scheme, the weight percentage of the ethanol is optimized, so that the silicon dioxide aerogel powder is better dissolved in the ethanol solution, the silicon dioxide aerogel powder and the epoxy acrylate resin are better reacted, the density of the modified silicon dioxide aerogel powder is further enhanced, and the compressive strength of the foam concrete is enhanced.

Preferably, the reinforcing fiber consists of polyvinyl alcohol fiber, aluminum silicate fiber and basalt fiber in the weight ratio of 1 (1-2) to (0.5-1).

Through adopting above-mentioned technical scheme, the preferred three kinds of fibre combinations of reinforcing fiber to cooperate better with modified silica aerogel powder, further strengthen the intensity of foam concrete.

Preferably, the raw material of the foam concrete further comprises 3-5 parts by weight of an accelerant, and the accelerant comprises at least one of hydroxypropyl methyl cellulose and hydroxyethyl cellulose.

By adopting the technical scheme, the accelerant is matched with the modified silicon dioxide aerogel powder after selecting at least one of hydroxypropyl methyl cellulose and hydroxyethyl cellulose, so that the aerogel powder is effectively dispersed, and the agglomeration phenomenon is reduced. Meanwhile, the modified silicon dioxide aerogel powder is promoted to be uniformly dispersed in a foam concrete system, the phase separation phenomenon between the aerogel powder and each raw material of the concrete is reduced, and the strength of the foam concrete is further enhanced.

Preferably, the raw materials of the foam concrete also comprise 1-3 parts by weight of ammonium alginate.

Through adopting above-mentioned technical scheme, after ammonium alginate added, effectively bond other raw materials in modified silica aerogel powder and the concrete and mix, reduce the phase separation phenomenon between aerogel powder and each raw materials of concrete, further strengthen the intensity of foam concrete.

Preferably, the foaming agent comprises at least one of a tea saponin foaming agent and an animal protein foaming agent.

By adopting the technical scheme, at least one of the tea saponin foaming agent and the animal protein foaming agent is adopted as the foaming agent, so that the foaming performance is stable, and the stability of the foam concrete is enhanced.

In a second aspect, the present application provides a method for preparing foam concrete, which adopts the following technical scheme:

a preparation method of foam concrete comprises the following preparation steps:

s1, mixing the modified silicon dioxide aerogel powder, cement and water uniformly to obtain a first mixture;

s2, mixing the first mixture with light mullite, mineral powder, silica fume and fly ash, and uniformly mixing to obtain a second mixture;

and S3, mixing the second mixture with the reinforced fibers, adding a foaming agent after uniformly mixing, and uniformly mixing to obtain the foam concrete.

By adopting the technical scheme, firstly, the modified silicon dioxide aerogel powder is mixed with substances such as cement and the like, and after the substances are uniformly mixed, substances such as light mullite, mineral powder and the like are added, so that the strength and the heat insulation performance of concrete are further enhanced; by adding the raw materials step by step, the foam concrete is endowed with better stability and uniformity.

Preferably, 3 to 5 parts by weight of the accelerator and 1 to 3 parts by weight of ammonium alginate are added in the step S1.

By adopting the technical scheme, after the accelerant and the ammonium alginate are added, the aerogel powder is effectively dispersed, the modified silicon dioxide aerogel powder is promoted to be uniformly dispersed in a foam concrete system, the phase separation phenomenon between the aerogel powder and each raw material of concrete is reduced, and the strength of the foam concrete is enhanced.

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

1. in the application, the silicon dioxide aerogel powder is modified, epoxy acrylate resin is coated on the gel skeleton, and the density of gel skeleton ions is enhanced under the condition of not influencing the porosity, so that the strength of the foam concrete is further enhanced; meanwhile, the density difference between the modified silicon dioxide aerogel powder and other raw materials of the concrete is reduced, and the phase separation phenomenon among the raw materials is reduced, so that the compressive strength of the foam concrete is further enhanced.

2. In this application, the preparation step of preferred modified silica aerogel powder, the weight percent of preferred ethanol liquid for silica aerogel powder reacts better with epoxy acrylate resin, further strengthens the density of modified silica aerogel powder, strengthens the compressive strength of foam concrete. The proportion of the reinforced fiber is optimized, and the accelerant and the ammonium alginate are added, so that the phase separation phenomenon between the modified silicon dioxide aerogel powder and each raw material is effectively reduced, and the strength of the foam concrete is further enhanced. The specific components of the foaming agent are optimized, and the foaming stability of the foam concrete is enhanced.

3. According to the preparation method, the raw materials are added step by step, so that the modified silicon dioxide aerogel powder is effectively dispersed, the phase separation phenomenon is reduced, and the strength and uniformity of the foam concrete are enhanced.

Detailed Description

The present application is described in further detail below.

The components and manufacturers in the examples are shown in Table 1.

TABLE 1 Components and manufacturers

Components	Model/specification	Manufacturer of the product
			Cement	P.O32.5MPa	Conch brand
Silica aerogel powder	A103/40nm	LANGFANG TAOGE NANO-MATERIAL Co.,Ltd.
			Epoxy acrylate resin	FX-8002-80	Fangxin resin
Polyvinyl alcohol fiber	P139543	Aladdin
			Aluminium silicate fibre	/	Shanghai Ruvor building materials Co Ltd
Hydroxypropyl methylcellulose	/	Ansen chemical industry
			Hydroxyethyl cellulose	/	Jiangsu Ofu Biotech Co., Ltd
Tea saponin foaming agent	REL-CZS99	Sienreili bioengineering Co., Ltd
			Animal protein foaming agent	FP-1	Chemical Limited of Jinan Wen bamboo
Polyacrylamide	9003-05-8	Pan (Shanghai) International trade Co., Ltd
			Latex powder	YG-6001	Shanghai Yunlian industries Ltd
Epoxy resin	E44 type	Pan (Shanghai) International trade Co., Ltd

Preparation example

Preparation example 1A modified silica aerogel powder was prepared by the following steps:

a1, mixing 40kg of silicon dioxide aerogel powder with 80kg of ethanol solution with the weight percentage of 40%, and mixing and dispersing for 3 hours to obtain a silicon dioxide aerogel powder treated substance;

a2, mixing the silicon dioxide aerogel powder processed product with 20kg of epoxy resin, 2kg of silane coupling agent kh550 and 0.3kg of initiator azobisisobutyronitrile at the temperature of 72 ℃, mixing and reacting for 4 hours, drying for 20 hours at the temperature of 40 ℃, and drying to obtain the modified silicon dioxide aerogel powder.

Preparation example 2A modified silica aerogel powder was prepared by the following steps:

a2, mixing the silicon dioxide aerogel powder processed product with 20kg of epoxy acrylate resin, a silane coupling agent kh550 and 0.3kg of initiator azobisisobutyronitrile at the temperature of 72 ℃, mixing and reacting for 4 hours, drying at the temperature of 40 ℃ for 20 hours, and drying to obtain the modified silicon dioxide aerogel powder.

Preparation example 3A modified silica aerogel powder was prepared, which was different from preparation example 2 in that the ethanol concentration was 70% by weight, the dispersion time was 1 hour, and the mixing time was 2.5 hours at a temperature of 80 ℃ in step S2.

Preparation example 4A modified silica aerogel powder was prepared, which was different from the preparation example 2 in that the weight percentage of the ethanol solution was 45%.

Preparation example 5A modified silica aerogel powder was prepared, which was different from preparation example 2 in that the ethanol solution was 55% by weight.

Examples

Example 1A foamed concrete comprising the specific components and weights shown in Table 2 was prepared by the following steps:

s1, mixing and stirring the modified silica aerogel powder prepared in the preparation example 1, cement and water at the stirring speed of 1000r/min, and uniformly stirring to obtain a first mixture;

s2, mixing and stirring the first mixture with light mullite, mineral powder, silica fume and fly ash at the stirring speed of 1000r/min, and uniformly stirring to obtain a second mixture;

and S3, mixing the second mixture with the reinforced fibers at a stirring speed of 800r/min, adding the foaming agent after uniformly stirring, and stirring at a stirring speed of 1200r/min to obtain the foam concrete after uniformly stirring.

Example 2A foamed concrete was different from example 1 in specific components and weights, and the specific components and weights included were as shown in Table 2.

Examples 3 to 6A foamed concrete was different from example 1 in that the modified silica aerogel powder was 30kg in weight, and preparation examples 2 to 5 corresponded to the modified silica aerogel powders of examples 3 to 6, respectively.

Examples 7-8A foamed concrete, differing from example 6 in the specific composition of the reinforcing fibers, was comprised of the specific components and weights shown in Table 2.

Examples 9-10A foamed concrete, differing from example 1 in that an accelerator was added in step S1, and the specific components and weights included were as shown in Table 2.

Examples 11-12A foamed concrete, different from example 1, was prepared by adding ammonium alginate in step S1, and comprising the specific components and weights shown in Table 2.

Examples 13-14A foamed concrete, differing from example 1 in the specific composition of the foaming agent, was comprised of the specific components and weights shown in Table 2.

Examples 15-16A foamed concrete, differing from example 6 in that an accelerator and ammonium alginate were added, and the specific components and weights included were as shown in Table 2.

TABLE 2 specific compositions and weights for examples 1-2, examples 7-16

Comparative example

Comparative example 1A foamed concrete was distinguished from example 1 in that an equal amount of unmodified silica aerogel powder was used instead of the modified silica aerogel powder.

Comparative example 2 a foamed concrete, differing from example 1 in that it does not contain reinforcing fibres.

Comparative example 3 a foamed concrete differs from example 1 in that an equal amount of glass fibres is used instead of reinforcing fibres.

Comparative example 4 a foamed concrete was distinguished from example 1 in that an equal amount of unmodified silica aerogel powder was used instead of the modified silica aerogel powder, and that no reinforcing fiber was contained.

Comparative example 5A foamed concrete, different from example 1, was prepared in that unmodified silica aerogel powder was used in the same amount as the modified silica aerogel powder, and glass fiber was used as the reinforcing fiber.

Comparative example 6: a foam concrete comprises the following raw materials in parts by weight: 100kg of cement, 30kg of fly ash, 25kg of silicon dioxide aerogel, 0.5kg of hydroxypropyl methyl cellulose, 1kg of polyacrylamide, 01kg of emulsion powder, 1kg of polypropylene fiber and 100kg of water. The included components are shown in table 1.

The preparation method comprises the following steps: and mixing and stirring the raw materials at the stirring speed of 1200r/min, and uniformly stirring to obtain the foam concrete.

Detection method

Experiment one: experimental sample of compressive strength: the samples of examples 1 to 16 and comparative examples 1 to 6 were each prepared as a test piece of a cubic body having a side length of 150mm, and the test pieces were designated as experimental samples 1 to 16 and comparative samples 1 to 6; there were 5 samples for each of the experimental samples 1-16 and the comparative samples 1-6.

An experimental instrument: a compression testing machine.

The experimental method comprises the following steps:

compressive strength test: the compressive strengths of the experimental samples 1-16 and the comparative samples 1-6 are evaluated by referring to the compressive strength test in the experimental method standard for concrete physical and mechanical properties of GB/T50081-2019, for example, the compressive strengths of 5 experimental samples 1 are respectively detected, and then the average value of the compressive strengths of 5 experimental samples 1 is taken as the final compressive strength of the experimental sample 1.

The experimental results are as follows: the compression strength tests of the experimental samples 1 to 16 and the comparative samples 1 to 6 are shown in Table 3.

Experiment two: concrete density experiment experimental sample: the samples of examples 1 to 16 and comparative examples 1 to 6 were prism test pieces of 150mm × 150mm × 600mm, and the samples obtained from examples 1 to 16 were respectively designated as experimental samples 1 to 16, the samples obtained from comparative examples 1 to 6 were respectively designated as comparative samples 1 to 7, and 5 of each of the experimental samples 1 to 16 and the comparative samples 1 to 6.

An experimental instrument: a precision balance.

The experimental method comprises the following steps: respectively detecting the weights of the 5 experimental samples 1 by using a precision balance, and calculating the corresponding concrete volume and density; the final density of sample 1 was then determined as the average of the densities of 5 samples 1.

The experimental results are as follows: concrete density tests of the experimental samples 1 to 16 and the comparative samples 1 to 6 are shown in Table 3.

Experiment three: heat insulation performance test samples: samples, which were cubes having sides of 150mm, were prepared using examples 1 to 16 and comparative examples 1 to 6, and the samples obtained from examples 1 to 16 were respectively designated as experimental samples 1 to 16, and the samples obtained from comparative examples 1 to 6 were respectively designated as comparative samples 1 to 6, and 5 samples were each used for experimental samples 1 to 16 and comparative sample 16.

An experimental instrument: thermal conductivity tester.

The experimental method comprises the following steps: detecting the heat conductivity coefficients of the experimental samples 1-16 and the comparative samples 1-6 respectively by using a heat conductivity coefficient tester; for example, the heat conductivity coefficients of 5 experimental samples 1 are respectively detected, and the average value of the heat conductivity coefficients of the 5 experimental samples 1 is taken as the final heat conductivity coefficient of the experimental sample 1; the heat conductivity coefficient experiments are carried out on experimental samples 2-17 and comparative samples 1-6 by adopting the method.

The experimental results are as follows: the results of the thermal conductivity of the experimental samples 1-16 and the comparative samples 1-6 are shown in Table 3.

TABLE 3 results of the experiments of the experimental samples 1 to 16 and the comparative samples 1 to 6

As can be seen from the data in Table 3, the compressive strength of the test samples 1-16 is 4.8-6.1MPa, and the density is 612-671kg/m³The thermal conductivity coefficient is 0.036-0.051W/(m.K); the compression strength of the comparative samples 1-6 is 2.9-4.2MPa, and the density is 543-³The heat conductivity coefficient is 0.053-0.093W/(m.K); the lower the thermal conductivity, the better the heat preservation and insulation performance. The experimental data show that the experimental samples 1 to 16 have higher compressive strength and better thermal conductivity than the comparative samples 1 to 6.

Comparing the experimental sample 1 and the comparative samples 1 to 4, it can be seen that the compressive strength of the foam concrete is improved after the silica aerogel powder is modified and the reinforcing fiber is added, which indicates that the strength of the concrete can be enhanced by the modified silica aerogel powder and the reinforcing fiber. Probably because the fibers have certain toughness, the density of the modified aerogel powder is improved to a certain extent, and the compressive strength of the foam concrete is further enhanced after the modified silicon dioxide is matched with the reinforcing fibers.

Comparing the experimental sample 1 with the comparative sample 1, the comparative sample 3 and the comparative sample 5, it can be seen that the strength of the foam concrete is enhanced when the reinforcing fibers are polyvinyl alcohol fibers, aluminum silicate fibers and basalt fibers. Probably because the selected fiber has higher strength and better matching effect with modified silicon dioxide aerogel powder, cement and the like, the compressive strength of the foam concrete is enhanced.

Comparing the experimental sample 1 with the experimental samples 3-4, it can be known that the epoxy acrylate resin is used for modifying the silicon dioxide aerogel powder, because the epoxy acrylate resin has better toughness, heat resistance and stability, the epoxy acrylate resin with double bonds is linked on the surface of the silicon particles through the silane coupling agent and the initiator, and further initiates a polymerization reaction, so that an epoxy acrylate resin coating film is generated on the surface of the silicon particles, a covalent bond is formed between the epoxy acrylate resin and the aerogel framework, the density of the silicon dioxide aerogel powder is improved, and the compressive strength of the foam concrete is further enhanced.

Comparing the experimental sample 3 with the experimental samples 5 to 6, it can be seen that the compressive strength of the foam concrete is enhanced to a certain extent by optimizing the concentration of the ethanol solution. Probably, the ethanol solution can better dissolve the silicon dioxide aerogel powder under the condition that the weight percentage is 45-55%, so that the silicon dioxide aerogel powder can better react with the epoxy acrylate resin, the density of the modified silicon dioxide aerogel powder is further enhanced, and the compressive strength of the foam concrete is enhanced.

It can be seen from comparison of experimental samples 6-8 that the preferred composition and weight ratio of the reinforcing fibers contribute to the compressive strength of the foamed concrete. Comparing the experimental sample 1 with the experimental samples 9-10, it can be seen that after the accelerant is added, the compressive strength of the foam concrete is enhanced, the heat conductivity coefficient is reduced, and the heat preservation and heat insulation performance is enhanced. Probably because the promoters hydroxypropyl methyl cellulose and hydroxyethyl cellulose are added to effectively disperse the modified silicon dioxide aerogel powder which is easy to agglomerate and precipitate, and simultaneously, the modified silicon dioxide aerogel powder has better mechanical property and further enhances the compressive strength of the foam concrete.

Comparing experiment sample 1 and experiment samples 11-12, it can be seen that the compressive strength of the foam concrete is improved after adding ammonium alginate. Probably because ammonium alginate has certain thickening and emulsifying functions, the modified silicon dioxide aerogel powder and other raw materials in the concrete are bonded and mixed, so that the phase separation phenomenon among the raw materials is effectively reduced, and the compressive strength of the foam concrete is further enhanced. Comparing the experimental sample 1 and the experimental samples 13-14, it can be seen that after the tea saponin foaming agent and the animal protein foaming agent are preferably used as the foaming agents, the compressive strength is also enhanced to a certain extent, probably because the bubbles generated by the foaming agents are stable, so that the stability of the concrete is effectively enhanced, and better compressive strength is obtained.

Comparing the experimental sample 6 with the experimental samples 15-16, the components and the weight ratio of the reinforcing fiber and the foaming agent are preferably selected, and the accelerator and the ammonium alginate are added simultaneously, so that the compressive strength of the foam concrete is enhanced, and the heat conductivity coefficient is reduced; and after the components are matched with each other, the increase range of the compressive strength and the heat insulation performance is higher.

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 foam concrete is characterized by comprising the following raw materials in parts by weight:

150 portions of cement and 250 portions of cement;

20-30 parts of fly ash;

40-60 parts of mineral powder;

10-20 parts of silica fume;

10-30 parts of modified silicon dioxide aerogel powder;

20-40 parts of reinforcing fibers;

5-8 parts of light mullite;

3-6 parts of a foaming agent;

100 portions of water and 200 portions of water;

2. The foamed concrete according to claim 1, wherein the preparation method of the modified aerogel comprises the following steps:

3. The foamed concrete according to claim 2, wherein in step a2, the ethanol solution is 45-55% by weight.

4. The foamed concrete according to claim 1, wherein the reinforcing fibers consist of polyvinyl alcohol fibers, aluminum silicate fibers and basalt fibers in a weight ratio of 1 (1-2) to (0.5-1).

5. The foamed concrete according to claim 1, further comprising 3 to 5 parts by weight of an accelerator comprising at least one of hydroxypropyl methylcellulose and hydroxyethyl cellulose.

6. The foamed concrete according to claim 1, wherein the raw material of the foamed concrete further comprises 1-3 parts by weight of ammonium alginate.

7. The foamed concrete according to claim 1, wherein the foaming agent comprises at least one of a tea saponin foaming agent and an animal protein foaming agent.

8. A method of producing a foamed concrete according to any one of claims 1 to 7 comprising the steps of:

9. The method of claim 8, wherein 3 to 5 parts by weight of the accelerator and 1 to 3 parts by weight of ammonium alginate are added in step S1.