CN114656221A

CN114656221A - High-temperature-resistant concrete containing silica aerogel and waste glass powder

Info

Publication number: CN114656221A
Application number: CN202210447640.1A
Authority: CN
Inventors: 解盼盼; 马国伟; 王里
Original assignee: Hebei University of Technology
Current assignee: Hebei University of Technology
Priority date: 2022-04-26
Filing date: 2022-04-26
Publication date: 2022-06-24

Abstract

The invention discloses high-temperature-resistant concrete containing silica aerogel and waste glass powder, which comprises 13-19 parts of ordinary portland cement, 0.05-0.45 part of silica aerogel, 0.6-3 parts of silica fume, 0.01-0.3 part of water reducing agent, 12-24 parts of quartz sand, 3-9 parts of river sand, 6-8 parts of glass powder and 4.5-10 parts of water according to parts by weight. According to the high-temperature-resistant concrete containing the silica aerogel and the waste glass powder, which is disclosed by the invention, the glass powder and the silica aerogel are added into the high-temperature-resistant concrete, and fine glass powder particles melted at a high temperature wrap the surfaces of the silica aerogel particles to form a layer of protective film, so that the silica aerogel is effectively prevented from contacting with cement and water, the silica aerogel is prevented from being changed from hydrophobicity to hydrophilicity, and the strength and the high-temperature resistance of the concrete are effectively improved.

Description

High-temperature-resistant concrete containing silica aerogel and waste glass powder

Technical Field

The invention relates to the technical field of concrete, in particular to high-temperature-resistant concrete containing silica aerogel and waste glass powder.

Background

With the rapid development of the urbanization in China and the improvement of the social production level, high-rise buildings and special buildings emerge endlessly. The rapid development of productivity also requires that natural gas, gas and electrical equipment can provide convenient working and living conditions for people indoors, which obviously increases the possibility of fire in buildings. The existing data show that if the service life of a high layer is counted by 30 years, the fire occurrence probability is as high as 42.15 percent; if the life of the high-rise building is 70 years, the probability of fire occurrence can reach 99%. Once a fire occurs, the building is exposed to a high temperature environment for a long time, and the building risks collapse, and about millions of fires occur in the world each year, and about 7 to 8 thousands of people lose lives.

The aerogel is a nanoscale porous solid material formed by replacing a liquid phase in gel with gas in a certain drying mode by a sol-gel method, most of the pore sizes of the aerogel are distributed in a nanoscale, the porosity of the aerogel is over 95%, and the aerogel is called as a solid material with the lowest thermal conductivity due to the extremely low thermal conductivity. Due to the characteristics of low thermal conductivity, high specific surface area, high temperature resistance and the like, the material is applied to high precision fields such as medium aviation and aerospace, physical research and the like. In recent years, more and more researchers have applied aerogels to the field of building materials because of their low thermal conductivity properties, trying to combine them with cementitious materials to make an insulating material. In the existing research, most of the research focuses on the incorporation mode of the aerogel or the research of the aerogel on the aspects of mechanical property and heat preservation, and other researchers add other materials such as expanded perlite, vitrified micro bubbles and fly ash floating beads into concrete, so that the strength improvement effect is not very obvious.

Glass is an amorphous inorganic non-metallic material, has good transparency and chemical stability, and is widely applied in life, such as various glassware, tableware, cups, dishes, glass daily necessities and ornaments; and (3) manufacturing exquisite artistic glass, vases, artificial glass gemstones, and very common bulbs, tubes, displays and the like. As a consumable product, the collection and utilization of waste glass have been attracting attention in recent years. At present, the recovery rate of domestic waste glass is basically about 50%, and the domestic waste glass is mainly recovered by a glass factory, wine bottles and the like, and the production of regenerated glass by using waste glass is a main way for utilizing the waste glass in China. The means for recycling and utilizing the waste glass is limited.

At present, the high-temperature resistance of the concrete compounded by aerogel and glass powder is not researched, and a material for improving the high-temperature resistance of the aerogel-containing concrete under the condition of not reducing the strength of the concrete is urgently needed.

Disclosure of Invention

The invention aims to provide high-temperature-resistant concrete containing silica aerogel and waste glass powder, so as to solve the problem that the aerogel concrete is poor in high-temperature resistance.

In order to achieve the purpose, the invention provides high-temperature-resistant concrete containing silica aerogel and waste glass powder, which comprises 13-19 parts of ordinary portland cement, 0.05-0.45 part of silica aerogel, 0.6-3 parts of silica fume, 0.01-0.3 part of water reducing agent, 12-24 parts of quartz sand, 3-9 parts of river sand, 6-8 parts of glass powder and 4.5-10 parts of water according to parts by weight. More preferably, the high-temperature resistant concrete comprises, by weight, 13-18.16 parts of ordinary portland cement, 12.68-24 parts of quartz sand, 3.32-8.4 parts of river sand, 0.6-3 parts of silica fume, 0.01-0.08 part of a water reducing agent, 4.5-10 parts of water, 0.05-0.45 part of aerogel and 6-8 parts of glass powder.

Preferably, the strength of the ordinary portland cement is not lower than 42.5, the density is 2800-3300Kg/m3, the specific surface area is 300-400m2/Kg, and the water-cement ratio is 0.5, and the thermal conductivity at normal temperature after standard curing for 28 days is 0.528W/(m.K). More preferably, Na is contained in ordinary portland cement₂O、MgO、A1₂O₃、SiO₂、P₂O₅、K₂O, CaO contents are respectively 1.0%, 8.2%, 11.1%, 24.9%, 0.1%, 0.6% and 47.0%. Ordinary portland cement is the main cementitious material and is the main source of strength of concrete.

Preferably, the silicon dioxide aerogel is produced by adopting a supercritical drying process, the particle size is 0.1-2.0mm, the pore diameter is 17-23nm, and the bulk density is 140kg/m in a natural bulk state³And the coefficient of thermal conductivity is 0.01-0.015W/(m.K) at normal temperature. More preferably, the silica aerogel has a particle size of 0.3 to 0.8 nm. Silica aerogels have hydrophobic properties.

Preferably, the silica fume has an average particle diameter of 0.1 to 50 μm and a density of 650-800kg/m³The specific surface area is 24-30m²(ii) in terms of/g. More preferably, the silica fume has an average particle diameter of 0.1 to 30 μm. More preferably, the silica fume has an average particle diameter of 0.1 to 15 μm.

The small particle size of the silica fume has the following advantages: the particle grading is reasonable, so that the strength of concrete is improved; secondly, the heat conductivity coefficient of the cured product is increased, and the flame retardant property is improved; thirdly, the concrete is not easy to react with other substances, does not react with most of acid and alkali, and the particles of the concrete are uniformly covered on the surface of the concrete molding object, so that the concrete has stronger corrosion resistance.

Preferably, the water reducing agent is one of a sulfonated melamine water reducing agent or a polycarboxylic acid water reducing agent. The water reducing agent can reduce the consumption of the original water of cement mortar, and can be adsorbed on the surface of concrete, so that a flocculation structure caused by the stirring of water and the concrete is broken up, and the fluidity and the workability of the mortar are improved.

Preferably, the bulk density of the sulfonated melamine water reducer is 400-800kg/m³The drying weight loss is 2.0-4.0%, the pH value is 9-12, and the water reduction rate is 15-36%; the bulk density of the polycarboxylic acid water reducing agent is 600-800kg/m³The pH value is 4-7, the water reducing rate is 30-50%, and the solid content is 20-40%.

Preferably, SiO in quartz sand₂The content is 90-99.8%, the granularity is 5-500 meshes, and the density is 1700-2000kg/m³The refractoriness is 1650-. More preferably, the quartz sand has a particle size of 40 to 70 mesh.

Preferably, the river sand has a particle size of 4-100 meshes and a fineness modulus of 2.0. More preferably, the particle size of the river sand is 50-65 meshes, and the surface of the river sand is smooth. River sand and quartz sand together constitute fine aggregate.

Preferably, the particle size of the glass powder is 0.15-0.30 mm. Collecting waste cullet, selecting, cleaning, drying, crushing and sieving to obtain glass powder with qualified particle size, wherein the main component of the glass powder is Na₂SiO₃、CaSiO₃、SiO₂Or Na₂O·CaO·6SiO₂From the above, it can be seen that the main component is a silicate double salt, which is an amorphous solid with a random structure.

A preparation method of high-temperature-resistant concrete containing silica aerogel and waste glass powder comprises the following steps:

(1) weighing ordinary portland cement, silica fume, quartz sand, river sand, silica aerogel, a water reducing agent, glass powder and water according to corresponding proportions;

(2) mixing and uniformly stirring cement, silica fume, glass powder, quartz sand and river sand to obtain a dry material mixture;

(3) adding quarter water into the silicon dioxide aerogel, and stirring to be in a uniform state to obtain an aerogel water solution;

(4) mixing one quarter of water with a water reducing agent, and uniformly stirring to obtain a water reducing agent solution;

(5) mixing the remaining half of water with the dry material mixture and uniformly stirring to obtain cement mortar;

(6) and mixing the aerogel aqueous solution with cement mortar, stirring until the mixture is uniformly mixed, adding the water reducing agent solution, and stirring until the mixture is uniformly mixed to obtain the high-temperature-resistant concrete.

Therefore, the high-temperature resistant concrete containing the silica aerogel and the waste glass powder, which adopts the structure, has the following beneficial effects:

1. the silicon dioxide aerogel in the invention is less in usage amount, so that the concrete achieves excellent strength, the usage amount of the aerogel is reduced under the condition of keeping the strength of the concrete, and the cost is saved.

2. The raw materials such as the silicon dioxide aerogel, the glass powder and the like are directly used for synthesizing the high-temperature-resistant concrete, secondary processing (such as ion surface treatment and the like) is not carried out, the preparation method is simple, the application of directly applying the silicon dioxide aerogel to the high-temperature-resistant concrete at present is less, and most of the silicon dioxide aerogel is in the form of mortar or paint.

3. The glass powder used in the invention is obtained by crushing and screening the collected waste glass, thereby increasing the means of recycling the waste glass in China, and the cost for preparing the high-temperature-resistant concrete can be reduced by adopting the waste glass.

4. The silica aerogel has high temperature resistance and can be used as an aggregate to improve the strength of concrete at high temperature, but the performance of the silica aerogel is changed from hydrophobic to hydrophilic at 500 ℃, so that the strength of the silica-containing aerogel is greatly lost after 500 ℃. The glass powder is melted at the temperature of 500-600 ℃, and the molten glass powder has three functions: firstly, gaps generated by the bursting of the concrete at high temperature can be filled in a molten state, and the adhesion is provided to ensure that the interior is complete; secondly, the concrete is continuously hydrated to increase the strength; the melted fine glass powder particles are wrapped on the surface of the aerogel particles to form a layer of protective film, so that the aerogel is effectively prevented from contacting with water, the aerogel is prevented from being converted to hydrophilic performance, the hydrophobic performance of the aerogel is kept to a certain degree, and the high-temperature resistance of the aerogel-containing concrete is improved. The glass powder is doped into the concrete containing aerogel, so that the reduction of the high-temperature resistance of the aerogel at the temperature of 500-600 ℃ caused by performance change can be compensated, the glass powder and the silicon dioxide aerogel have a coupling effect, and the high-temperature resistance of the concrete containing the silicon dioxide aerogel and the glass powder is improved.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

FIG. 1 shows the morphology change of the refractory concrete prepared in example 1 before and after the temperature of 900 ℃;

FIG. 2 shows the morphology change of the refractory concrete prepared in comparative example 1 before and after the temperature of 900 ℃.

Detailed Description

The present invention will be further described below, and it should be noted that the present embodiment is based on the technical solution, and a detailed implementation manner and a specific operation process are provided, but the present invention is not limited to the present embodiment.

Example 1

The high-temperature resistant concrete of the embodiment 1 comprises the following components in parts by weight:

15 portions of ordinary Portland cement with the strength of 42.5, 1 portion of silica fume with the particle size of 0.1 to 15 mu m, 7.5 portions of glass powder, 6.68 portions of water, 15 portions of quartz sand with the particle size of 40 to 70 meshes, 3.5 portions of river sand with the particle size of 50 to 65 meshes, and 700kg/m of density³0.01 part of water reducing agent with water reducing rate of 36 percent and 0.06 part of silica aerogel with 0.3-1.0mm (thermal conductivity coefficient 0.013W/(m.K)).

The preparation process of the high-temperature resistant concrete comprises the following steps: the method comprises the following steps:

(2) pouring cement, silica fume, glass powder, quartz sand and river sand into a stirring pot, and uniformly stirring for 2 minutes to obtain a dry material mixture;

(3) adding quarter water into the silicon dioxide aerogel, and stirring for 2 minutes to a uniform state to obtain an aerogel water solution;

(4) mixing the quarter water with a water reducing agent, and uniformly stirring to obtain a water reducing agent solution;

(5) mixing the remaining half of water with the dry material mixture, and uniformly stirring for 3 minutes to obtain cement mortar;

(6) mixing the aerogel aqueous solution with cement mortar, stirring for 3 minutes in a stirring pot until the aerogel aqueous solution and the cement mortar are uniformly mixed, adding the water reducing agent solution, and stirring for 3 minutes until the water reducing agent solution and the water reducing agent solution are uniformly mixed to obtain high-temperature-resistant concrete;

(7) the high-temperature resistant concrete is put into a mould in a layered mode, then a casting object is covered by a plastic film, and the casting object is maintained for 24 hours at normal temperature;

(8) and then placing the concrete into a standard curing room with the temperature of 20-25 ℃ and the relative humidity of 90-95 percent, and curing for 7 days to obtain a high-temperature resistant concrete finished product.

Example 2

The high-temperature resistant concrete of the embodiment 2 comprises the following components in parts by weight:

15 portions of ordinary Portland cement with the strength of 42.5, 1 portion of silica fume with the particle size of 0.1 to 15 mu m, 7 portions of glass powder, 6.68 portions of water, 16.5 portions of quartz sand with the particle size of 40 to 70 meshes, 2.58 portions of river sand with the particle size of 50 to 65 meshes, and 700kg/m of density³0.01 part of water reducing agent with water reducing rate of 36 percent and 0.10 part of silica aerogel with 0.3-1.0mm (thermal conductivity coefficient 0.013W/(m.K)). The material preparation procedure was the same as in example 1.

Example 3

The high-temperature resistant concrete of the embodiment 3 comprises the following components in parts by weight:

15 portions of ordinary Portland cement with the strength of 42.5, 1 portion of silica fume with the diameter of 0.1 to 15 mu m, 8 portions of glass powder, 6.68 portions of water, 16 portions of quartz sand with the particle size of 40 to 70 meshes, 2 portions of river sand with the particle size of 50 to 65 meshes, and 700kg/m of density³0.01 part of water reducing agent with water reducing rate of 36 percent and 0.14 part of silica aerogel with 0.3-1.0mm (thermal conductivity coefficient of 0.013W/(m.K)). The material preparation procedure was the same as in example 1.

Comparative example 1

The concrete of comparative example 1 comprises the following components in parts by weight:

15 portions of ordinary Portland cement with the strength of 42.5, 1 portion of silica fume with the particle size of 0.1 to 15 mu m, 3.2 portions of water, 10.51 portions of quartz sand with the particle size of 40 to 70 meshes, 10 portions of river sand with the particle size of 50 to 65 meshes, and 700kg/m of density³0.36 part of water reducing agent with water reducing rate of 36 percent and 0.1 part of silica aerogel with 0.3-1.0mm (thermal conductivity coefficient 0.013W/(m.K)). The material preparation procedure was the same as in example 1.

Comparative example 2

The concrete of comparative example 2 comprises the following components in parts by weight:

9 portions of ordinary Portland cement with the strength of 42.5, 1 portion of silica fume with the diameter of 0.1 to 15 mu m, 3.2 portions of water, 17 portions of quartz sand with the particle size of 40 to 70 meshes, 1.75 portions of river sand with the particle size of 50 to 65 meshes, and the density of 700kg/m³0.36 part of water reducing agent with the water reducing rate of 36 percent and 7 parts of glass powder. The material preparation procedure was the same as in example 1.

Comparative example 3

The concrete of comparative example 3 comprises the following components in parts by weight:

9 portions of ordinary Portland cement with the strength of 42.5, 1 portion of silica fume with the diameter of 0.1 to 15 mu m, 3.2 portions of water, 17 portions of quartz sand with the particle size of 40 to 70 meshes, 1.75 portions of river sand with the particle size of 50 to 65 meshes, 0.36 portion of water reducing agent with the density of 500 kg/m3 and the water reducing rate of 36 percent, and 9 portions of glass powder. The material preparation procedure was the same as in example 1.

The high temperature resistant concrete products cured in examples 1 to 3 and the cured concrete products cured in comparative examples 1 to 3 were demolded from a cubic mold of 70.7X 70.7mm, and various performance tests were performed thereon, and the test results are shown in tables 1 to 3.

TABLE 1 slump, extension, penetration resistance of concrete

Examples and comparative examples	Slump (mm)	Extension degree (mm)	Penetration resistance (KPa)
				Example 1	46	190	25
Example 2	48	192	28
				Example 3	47	194	27
Comparative example 1	55	210	19
				Comparative example 2	52	202	21
Comparative example 3	41	181	30

TABLE 2 compressive strength of concrete before and after high temperature (MPa)

TABLE 3 thermal conductivity of concrete before and after high temperature (W/(m.K))

The silica aerogel and the glass powder are added in the embodiments 1 to 3, the slump and the expansion of the concrete in the embodiments and the comparative examples are respectively tested according to corresponding methods in GB/T14902-. The penetration resistance of the concrete of the examples and the comparative examples was tested according to the corresponding method in GB/T50080-2002, and the result was 19-30KPa, and the high temperature resistant concrete of the examples had good workability. After the mechanical property test before and after the high-temperature treatment and the determination of the heat conductivity coefficient at different temperatures are carried out, the test results are shown in tables 2 and 3, after the high-temperature treatment, the compressive strength of the embodiment is higher than that of the comparative example, and the strength loss is lower, so that the finished product of the high-temperature resistant concrete prepared by the embodiment still keeps the same state as that before the high temperature after the high-temperature treatment at 900 ℃ in figure 1, and the finished product of the concrete prepared by the comparative example 1 (without adding glass powder) is cracked and changed into a plurality of small blocks after the high temperature treatment at 900 ℃ in figure 2, so that the concrete of the embodiments 1-3 has good high-temperature resistance.

The action mechanism of the glass powder and the silicon dioxide aerogel is as follows:

the silica aerogel can bear the high temperature of 1100 ℃, however, the performance of the silica aerogel is changed from hydrophobic to hydrophilic at the temperature of 500-600 ℃, so that the original structure is changed, and the high temperature resistance of the aerogel is reduced. Research shows that the concrete containing the silica aerogel can efficiently resist high-temperature erosion before 500 ℃, and has less strength loss after high temperature compared with the concrete not doped with the silica aerogel, but the strength loss of the aerogel concrete after 500 ℃ is more and is similar to that of the concrete not doped with the aerogel. The glass powder is melted at the temperature of 500-600 ℃, and the molten glass powder has the functions of filling up the defects generated by the concrete at high temperature, bonding the set cement around the defects and the aggregate together and reducing the porosity; secondly, the activity of the active silicon dioxide in the glass powder is activated at high temperature, and the active silicon dioxide reacts with calcium hydroxide to generate C-S-H gel, so that the strength can be increased; the melted fine glass powder particles are wrapped on the surface of the silicon dioxide aerogel particles to form a layer of protective film, so that the silicon dioxide aerogel is effectively prevented from contacting with cement and water, the silicon dioxide aerogel is prevented from generating cracks, and the silicon dioxide aerogel is prevented from being converted into hydrophilic. Therefore, the glass powder is doped into the concrete containing the silicon dioxide aerogel to make up the reduction of the high temperature resistance of the aerogel at the temperature of 500-600 ℃ caused by performance change, and the coupling effect of the glass powder and the aerogel improves the high temperature resistance of the concrete.

Therefore, the high-temperature-resistant concrete containing the silica aerogel and the waste glass powder with the structure is adopted, the glass powder and the silica aerogel are added into the high-temperature-resistant concrete, fine glass powder particles melted at high temperature wrap the surfaces of the silica aerogel particles to form a layer of protective film, the silica aerogel is effectively prevented from contacting with cement and water, the silica aerogel is prevented from being changed from hydrophobicity to hydrophilicity, and the strength and the high-temperature resistance of the concrete are effectively improved.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the invention without departing from the spirit and scope of the invention.

Claims

1. The high-temperature-resistant concrete containing the silica aerogel and the waste glass powder is characterized in that: the high-temperature resistant concrete comprises, by weight, 13-19 parts of ordinary portland cement, 0.05-0.45 part of silica aerogel, 0.6-3 parts of silica fume, 0.01-0.3 part of a water reducing agent, 12-24 parts of quartz sand, 3-9 parts of river sand, 6-8 parts of glass powder and 4.5-10 parts of water.

2. The high temperature resistant concrete containing silica aerogel and waste glass powder according to claim 1, wherein: the strength of the ordinary Portland cement is not lower than 42.5, and the density is 2800-³The specific surface area is 300-400m²PerKg, the thermal conductivity is 0.528W/(mK).

3. The high temperature resistant concrete containing silica aerogel and waste glass powder according to claim 1, wherein: the silicon dioxide aerogel is produced by a supercritical drying process, the particle size is 0.1-2.0mm, the pore diameter is 17-23nm, and the bulk density is 140kg/m in a natural bulk state³The coefficient of thermal conductivity is 0.01-0.015W/(m.K) at normal temperature.

4. The high temperature resistant concrete containing silica aerogel and waste glass powder according to claim 1, wherein: the silica fume has an average particle diameter of 0.1-50 μm and a density of 650-800kg/m³The specific surface area is 24-30m²/g。

5. The high temperature resistant concrete containing silica aerogel and waste glass powder according to claim 1, wherein: the water reducing agent is one of sulfonated melamine water reducing agent or polycarboxylic acid water reducing agent.

6. The high temperature resistant concrete containing silica aerogel and waste glass powder according to claim 5, wherein: the bulk density of the sulfonated melamine water reducing agent is 400-800kg/m³The drying weight loss is 2.0-4.0%, the pH value is 9-12, and the water reduction rate is 15-36%; the bulk density of the polycarboxylic acid water reducing agent is 600-800kg/m³The pH value is 4-7, the water reducing rate is 30-50%, and the solid content is 20-40%.

7. The high temperature resistant concrete containing silica aerogel and waste glass powder according to claim 1, wherein: SiO in quartz sand₂The content is 90-99.8%, the granularity is 5-500 meshes, and the density is 1700-2000kg/m³The refractoriness is 1650-.

8. The high temperature resistant concrete containing silica aerogel and waste glass powder according to claim 1, wherein: the river sand has a granularity of 4-100 meshes and a fineness modulus of 2.0.

9. The high temperature resistant concrete containing silica aerogel and waste glass powder according to claim 1, wherein: the grain diameter of the glass powder is 0.15-0.30 mm.

10. The method for preparing high temperature resistant concrete containing silica aerogel and waste glass powder according to any one of claims 1 to 9, wherein: the method comprises the following steps: