CN111848213A

CN111848213A - Heat-insulation concrete

Info

Publication number: CN111848213A
Application number: CN202010717705.0A
Authority: CN
Inventors: 黄安良; 孙福新; 刘梓骏; 陈慧敏; 李彬锋; 邓杰豪
Original assignee: Guangzhou Guangfeng Concrete Co ltd
Current assignee: Foshan Runqianyu Intellectual Property Service Co ltd
Priority date: 2020-07-23
Filing date: 2020-07-23
Publication date: 2020-10-30
Anticipated expiration: 2040-07-23
Also published as: CN111848213B

Abstract

The application relates to the technical field of concrete preparation, in particular to heat-insulating concrete which is prepared from the following raw materials in parts by mass: 100-200 parts of cement, 120-160 parts of fly ash, 200-300 parts of coarse aggregate, 260-400 parts of river sand, 80-90 parts of silicon carbide, 50-75 parts of nano calcium carbonate, 10-20 parts of aluminum powder, 35-55 parts of fiber, 2-5 parts of water reducing agent and 70-120 parts of water. The application provides a thermal-insulated heat preservation concrete has good compressive property, crack resistance and heat preservation and heat-proof properties.

Description

Heat-insulation concrete

Technical Field

The invention relates to the technical field of concrete preparation, in particular to heat insulation concrete.

Background

Concrete is the most widely applied material in civil engineering, but concrete has the defects of poor pressure resistance, high brittleness, easy water seepage, poor heat insulation performance and the like, so that when houses and other residential buildings are constructed, gaps are easy to seep water, and the heat insulation effect is poor.

In the existing concrete preparation process, in order to realize high heat insulation performance, concrete is usually prepared into foam concrete, the high heat insulation performance can be realized, the heat conductivity coefficient can reach 0.18W/m.K, but the compression strength of the foam concrete is poor, the foam concrete is difficult to be used for bearing of buildings, and the service life of the buildings is further influenced.

In the existing concrete preparation process, in order to improve the strength of concrete, a polymer adhesive or polymer fibers are usually added into the concrete, and the polymer fills gaps of the concrete, so that the gap rate of the concrete is reduced, and the strength of the concrete is improved, but the heat insulation performance of the concrete is not affected at all.

Disclosure of Invention

The invention aims to provide heat insulation concrete which is beneficial to improving the heat insulation performance of the concrete under the condition of ensuring the good compression resistance and cracking resistance of the concrete.

In order to achieve the purpose, the invention provides the following technical scheme:

the heat insulation concrete is prepared from the following raw materials in parts by mass:

cement 150-280 parts

320 portions of coal ash and 430 portions

200 portions and 300 portions of coarse aggregate

River sand 350-420 parts

100 portions of vermiculite powder and 120 portions of

30-50 parts of aluminum powder

50-80 parts of fiber

10-20 parts of water reducing agent

80-140 parts of water.

By adopting the technical scheme, cement, fly ash, coarse aggregate and river sand are used as main raw materials of the heat-insulation concrete, and the addition of the vermiculite powder is beneficial to enhancing the structural strength of the heat-insulation concrete on one hand, and on the other hand, the vermiculite powder has good adsorbability and heat-insulation performance, so that the fiber plays a reinforcing role in the concrete raw material, and meanwhile, the fiber has good impermeability, impact resistance and fire resistance, so that the structural strength of the heat-insulation concrete is improved; in addition, the vermiculite powder with good adsorbability can be adsorbed on the surface of the fiber, so that the heat-insulating concrete is favorable for improving the heat-insulating performance of the concrete under the condition of ensuring good compression resistance and cracking resistance.

Further, the raw materials also comprise 80-130 parts by mass of hollow glass beads.

Further, the average particle fineness of the hollow glass beads is 0.02-0.05 mm.

By adopting the technical scheme, the hollow glass beads are added, so that the compressive strength of the heat-insulating concrete is favorably enhanced, and the heat-insulating concrete is not easy to crack when being subjected to pressure.

Further, the vermiculite powder is modified vermiculite powder, and the preparation method of the modified vermiculite powder comprises the following steps:

preparing raw materials: preparing 10-20ml of aluminum sulfate solution, urea and Al in the aluminum sulfate solution for each gram of expanded vermiculite³⁺The mass ratio of (8-15): 1, the volume ratio of concentrated sulfuric acid to aluminum sulfate solution is 1: (400-500);

mixing expanded vermiculite, urea, concentrated sulfuric acid and aluminum sulfate solution according to the raw material ratio, stirring for 18-32 hours at 80-100 ℃, eluting and drying to obtain modified vermiculite, drying the obtained solid for 9-11 hours at the temperature of 100 ℃ plus 115 ℃, and then grinding to obtain modified vermiculite powder.

By adopting the technical scheme, a plurality of holes are formed on the layered structure of the vermiculite powder, impurities in the holes are dissolved out by sulfuric acid solution to dredge the pore passages of the vermiculite powder, the adsorption capacity of the vermiculite powder is further improved, a large number of aluminum oxide particles are embedded between the sheets of the expanded vermiculite, the heat conductivity coefficient of the expanded vermiculite is reduced, the specific sheet structure of the expanded vermiculite has heat flow reflection capacity, the pore volume of the pores between the layers of the modified expanded vermiculite is reduced, the convection heat transfer path is blocked, and the heat insulation performance of the heat insulation concrete is further enhanced; meanwhile, a large number of uniform nano micropores are formed among the modified vermiculite layers, so that the compressive strength of the heat insulation concrete is increased.

Furthermore, the concentration of the aluminum sulfate solution is 0.05-0.5 mol/L.

Further, the average particle fineness of the modified vermiculite powder is in a range of 0.06-0.075 mm.

By adopting the technical scheme, the average particle fineness range of the modified vermiculite powder is controlled to be 0.06-0.075mm, so that the modified vermiculite powder can be more uniformly and fully filled in gaps in coarse aggregate, and the compression strength and the heat preservation and insulation performance of the heat insulation concrete can be further improved.

Further, the coarse aggregate is prepared from ceramsite, granite gravel and basalt gravel in a mass ratio of 1: and (2-3) 1.

By adopting the technical scheme, the ceramsite has the advantages of high strength and light weight, and the granite macadam has good heat-resistant stability and compressive strength; the compression strength of the basalt macadam is high; the coarse aggregate is prepared from the ceramsite, the granite macadam and the basalt macadam in a specific mass ratio range, so that the structural strength of the heat-insulation concrete is ensured, and the heat-resistance stability of the heat-insulation concrete is improved.

Further, the fibers are polypropylene fibers or basalt fibers.

Further, the fiber is prepared from polypropylene fiber and basalt fiber in a mass ratio of (1-2): 1, in a mixture of the components.

By adopting the technical scheme, the polypropylene fiber can effectively control microcracks of the high-strength concrete caused by heat generated in the cement hydration process, prevent and inhibit the formation and development of the concrete primary cracks, greatly improve the anti-cracking and anti-permeability performance and the anti-abrasion performance of the high-strength concrete, and increase the toughness of the concrete, thereby prolonging the service life of the concrete. The basalt fiber has the effects of high compressive strength and high temperature resistance.

Further, the heat insulation concrete is prepared from the following raw materials in parts by mass:

cement 180-280 parts

380 portions of fly ash and 430 portions of

230 portions of coarse aggregate and 300 portions of

390 portions of river sand and 420 portions of sand

100 portions and 130 portions of hollow glass microspheres

110 portions of vermiculite powder and 120 portions of

35-50 parts of aluminum powder

65-80 parts of fiber

13-20 parts of water reducing agent

100 portions of water and 140 portions of water.

250 portions of cement

415 parts of fly ash

250 portions of coarse aggregate

410 portions of river sand

110 portions of hollow glass beads

118 parts of vermiculite powder

45 parts of aluminum powder

75 portions of fiber

15 portions of water reducing agent

130 parts of water.

By adopting the technical scheme, the heat insulation concrete prepared from the specific components and the specific mass part range has good compressive strength and heat insulation performance.

In conclusion, the invention has the following beneficial effects:

1. the cement, the fly ash, the coarse aggregate and the river sand are used as main raw materials of the heat-insulation concrete, and the addition of the vermiculite powder is beneficial to enhancing the structural strength of the heat-insulation concrete on one hand, and on the other hand, the vermiculite powder has good adsorbability and heat-insulation performance, so that the fiber plays a role in reinforcing the concrete raw materials, and meanwhile, the fiber has good permeability resistance, impact resistance and fire resistance, and is beneficial to improving the structural strength of the heat-insulation concrete; in addition, the vermiculite powder with good adsorbability can be adsorbed on the surface of the fiber, so that the heat-insulating concrete is favorable for improving the heat-insulating performance of the concrete under the condition of ensuring good compression resistance and cracking resistance.

2. A plurality of holes are formed on the layered structure of the vermiculite powder, impurities in the holes are dissolved out by sulfuric acid solution to dredge the pore passages of the vermiculite powder, the adsorption capacity of the vermiculite powder is further improved, a large number of alumina particles are embedded between the sheets of the expanded vermiculite, the heat conductivity coefficient of the expanded vermiculite is reduced, the specific sheet structure of the expanded vermiculite has heat flow reflection capacity, the pore volume of the pores between the layers of the modified expanded vermiculite is reduced, the convection heat transfer path is blocked, and the heat insulation performance of the heat insulation concrete is further enhanced; meanwhile, a large number of uniform nano micropores are formed among the modified vermiculite layers, so that the compressive strength of the heat insulation concrete is increased.

3. The polypropylene fiber can effectively control microcracks of the high-strength concrete caused by heat generated in the cement hydration process, prevent and inhibit the formation and development of the concrete primary cracks, greatly improve the anti-cracking and anti-permeability performance and the anti-abrasion performance of the high-strength concrete, and increase the toughness of the concrete, thereby prolonging the service life of the concrete. The basalt fiber has the effects of high compressive strength and high temperature resistance.

Detailed Description

The following examples further illustrate the invention in detail.

In the following examples, Portland cement of Huarun brand P.O42.5R was used as the cement.

In the following examples, a polycarboxylic acid water reducing agent manufactured by basf and having a model number of rheopolus 411 was used as the water reducing agent.

In the following examples, class II fly ash from a Baifeng mineral processing plant, Lingshu county, was used as the fly ash.

In the following examples, basalt fiber and polypropylene fiber were purchased from Ding economic development LLC of Wuhan, wherein the polypropylene fiber has a specification of 12mm, and the basalt fiber has a specification of 12 mm.

In the following examples, all the apparatuses used in the production method of the present invention, such as a stirrer, a pulverizer, etc., were conventionally used.

Table 1 components and parts by mass (kg) of the heat insulating concrete of examples 1 to 9.

Example 1

The components and the parts by mass of the raw materials of the heat-insulating concrete are shown in the table 1.

In this example, the fibers are polypropylene fibers. The coarse aggregate is ceramsite. The vermiculite powder is prepared by crushing vermiculite by a crusher, and the average particle fineness of the vermiculite powder is 0.06 mm.

The preparation method of the heat insulation concrete comprises the following steps:

and S1, mixing and stirring the water and the cement in corresponding parts by mass by using a stirrer at 26 ℃ to obtain a cement paste mixture.

And S2, adding river sand and fly ash in corresponding parts by mass into the cement paste mixture, and stirring at a rotating speed of 500r/min for 15min to obtain cement mortar.

S3, mixing the coarse aggregate in the corresponding mass part with the vermiculite powder, the aluminum powder and the fibers in the corresponding mass part by using a stirrer, stirring at the speed of 500r/min for 35min, then adding the water reducing agent in the corresponding mass part, and stirring for 45min to obtain the heat insulation concrete.

Example 2

A thermal insulation concrete is different from the concrete of the embodiment 1 in that: the average particle fineness of the hollow glass beads was 0.02 mm.

Example 3

A heat insulating concrete, which is different from the concrete of example 2 in that: the fibers in this example are basalt fibers.

Example 4

A heat insulating concrete, which is different from example 3 in that: the fibers in the embodiment are formed by mixing polypropylene fibers and basalt fibers in a mass ratio of 1: 1, in a mixture of the components.

Example 5

A heat insulating concrete, which is different from example 4 in that: in this embodiment, the coarse aggregate is prepared from ceramsite, granite macadam and basalt macadam in a mass ratio of 1: 2: 1.

Example 6

A thermal insulation concrete is different from the concrete of example 5 in that: the coarse aggregate is prepared from ceramsite, granite macadam and basalt macadam in a mass ratio of 1: 3: 1.

Example 7

A heat insulating concrete, which is different from example 6 in that: in this embodiment, the vermiculite powder is modified vermiculite powder, and the preparation method of the modified vermiculite powder is as follows:

preparing raw materials: the concentration of the aluminum sulfate solution is 0.05mol/L, 10ml of the aluminum sulfate solution is prepared for each gram of expanded vermiculite, and Al in the urea and aluminum sulfate solution³⁺The mass ratio of (a) to (b) is 8: 1, the volume ratio of concentrated sulfuric acid to aluminum sulfate solution is 1: 400.

mixing expanded vermiculite, urea, concentrated sulfuric acid and aluminum sulfate solution according to the raw material ratio, stirring for 18 hours at 80 ℃, eluting and drying to obtain modified vermiculite, drying the obtained solid for 9 hours at 100 ℃, and then grinding to obtain modified vermiculite powder.

In this example, the average particle fineness of the modified vermiculite powder was 0.06 mm.

Example 8

A heat insulating concrete, which is different from example 7 in that: in this example, the preparation method of the modified vermiculite powder is as follows: preparing raw materials: the concentration of the aluminum sulfate solution is 0.3mol/L, 15ml of the aluminum sulfate solution is prepared for each gram of expanded vermiculite, and Al in the urea and aluminum sulfate solution³⁺The mass ratio of (a) to (b) is 12: 1, the volume ratio of concentrated sulfuric acid to aluminum sulfate solution is 1: 450.

mixing expanded vermiculite, urea, concentrated sulfuric acid and aluminum sulfate solution according to the raw material proportion, stirring for 25 hours at 90 ℃, eluting and drying to obtain modified vermiculite, drying the obtained solid for 10 hours at 110 ℃, and then grinding to obtain modified vermiculite powder.

In this example, the average particle fineness of the modified vermiculite powder was 0.065 mm.

Example 9

A heat insulating concrete, which is different from example 8 in that:

in this example, the preparation method of the modified vermiculite powder is as follows:

preparing raw materials: preparing 20ml of aluminum sulfate solution, urea and Al in the aluminum sulfate solution for each gram of expanded vermiculite³⁺The mass ratio of (a) to (b) is 15: 1, the volume ratio of concentrated sulfuric acid to aluminum sulfate solution is 1: 500.

mixing expanded vermiculite, urea, concentrated sulfuric acid and aluminum sulfate solution according to the raw material ratio, stirring for 32 hours at 100 ℃, eluting and drying to obtain modified vermiculite, drying the obtained solid for 11 hours at 115 ℃, and then grinding to obtain modified vermiculite powder.

In this example, the average particle fineness of the modified vermiculite powder was 0.075 mm.

Table 2 shows the composition and parts by mass (kg) of the raw materials used in examples 10 to 15 for producing heat insulating concrete.

Example 10

A heat insulating concrete, which is different from example 9 in that: the components and parts by mass of the raw materials are shown in table 2.

Example 11

A heat insulating concrete, which is different from example 10 in that: the components and parts by mass of the raw materials are shown in table 2.

Example 12

A heat-insulating concrete which is different from example 11 in that the components and parts by mass of the raw materials are shown in Table 2.

Example 13

An insulating concrete, which is different from the concrete of example 12 in that: the components and parts by mass of the raw materials are shown in table 2.

Example 14

A heat insulating and preserving concrete, which is different from the concrete of example 13 in that:

the average particle fineness of the hollow glass beads was 0.03 mm. The coarse aggregate is prepared from ceramsite, granite macadam and basalt macadam in a mass ratio of 1: 2.5: 1. The fiber is prepared from polypropylene fiber and basalt fiber in a mass ratio of 2:1, in a mixture of the components.

preparing raw materials: the concentration of the aluminum sulfate solution is 0.3mol/L, 15ml of the aluminum sulfate solution is prepared for each gram of expanded vermiculite, and Al in the urea and aluminum sulfate solution³⁺The mass ratio of (a) to (b) is 12: 1, the volume ratio of concentrated sulfuric acid to aluminum sulfate solution is 1: 450.

Example 15

An insulating concrete, which is different from the concrete of example 14 in that: the components and parts by mass of the raw materials are shown in table 2. The average particle fineness of the hollow glass beads was 0.05 mm.

Comparative example 1

An insulating concrete, which is different from the concrete of example 14 in that: the heat insulation concrete is prepared from the following raw materials in parts by mass:

150 portions of cement

320 portions of fly ash

200 parts of coarse aggregate

350 parts of river sand

30 parts of aluminum powder

150 parts of fiber

10 portions of water reducing agent

80 parts of water.

Comparative example 2

An insulating concrete, which is different from the concrete of example 14 in that: medical stone powder is used to replace vermiculite powder.

Comparative example 3

An expanded vermiculite powder concrete disclosed in chinese patent No. CN104058654B was used as comparative example 3.

The test data of each example and comparative example are shown in Table 3.

Heat-insulating concrete test pieces were prepared according to examples 1 to 15 and comparative examples 1 to 3, and the test pieces 1 to 18 were subjected to the following experiments and the test results are shown in Table 3.

Experiment 1

The 28d compressive strength (MPa) and the water absorption (%) of the test blocks 1-18 are respectively tested according to the compressive strength test detection in GB/T50081-2019 concrete physical and mechanical property test method Standard.

Experiment 2

The thermal conductivity (W/m.K) of the test blocks 1 to 18 was measured according to GB/T10294-2008 "method for measuring thermal insulation material steady-state thermal resistance and related characteristics by guarded hot plate method".

Table 3 test blocks 1-18 test results after experiments 1-2.

The raw materials of the test block 1 do not adopt hollow glass beads, the test block 2 adopts hollow glass beads with the average particle fineness of 0.02mm, and the data in the table 3 show that the compression strength of the test block 1 is smaller than that of the test block 2, and the thermal conductivity coefficient of the test block 1 is larger than that of the test block 2, so that the compression strength of the heat-insulating concrete is favorably enhanced by adding the hollow glass beads, and the heat-insulating concrete is not easy to crack under pressure; simultaneously, the hollow glass bead is favorable to filling the hole between the cement granule, thereby make thermal-insulated heat preservation concrete's closely knit degree improve, and then be favorable to improving thermal-insulated heat preservation concrete's compressive strength, make thermal-insulated heat preservation concrete be difficult to the fracture when receiving pressure, and simultaneously, the hollow glass bead still has certain mobility, and the inside of hollow glass bead is rarefied gas, make thermal-insulated heat preservation concrete possess matter light and thermal-insulated heat preservation, thereby make thermal-insulated heat preservation concrete accessible hollow glass bead's flow in order to realize certain elastic deformation, and then have stronger compressive strength when being favorable to thermal-insulated heat preservation concrete to keep its superior performance.

The test block 2 adopts polypropylene fibers, the test block 3 adopts basalt fibers, and the test block 4 adopts polypropylene fibers and basalt fibers in a mass ratio of 1: 1, in a mixture of the components. It can be seen from the data in table 3 that the compressive strength of the test block 2 is similar to that of the test block 3, and the compressive strength of the single test block 4 is obviously higher than that of the test blocks 2 and 3, which indicates that the polypropylene fiber can effectively control the microcracks of the high-strength concrete caused by heat generated in the cement hydration process, prevent and inhibit the formation and development of the concrete primary cracks, greatly improve the anti-cracking and anti-permeability performance, the anti-abrasion performance and the toughness of the high-strength concrete, and increase the service life of the concrete. The basalt fiber has the effects of high compressive strength and high temperature resistance. The fiber prepared from the polypropylene fiber and the basalt fiber according to a specific proportion greatly improves the impermeability, compressive strength and heat insulation performance of the heat insulation concrete.

The coarse aggregate of the test block 4 is ceramsite; the coarse aggregate adopted by the test block 5 is prepared from ceramsite, granite gravel and basalt gravel in a mass ratio of 1: 2: 1. The ceramsite has the advantages of high strength and light weight, and the granite macadam has good heat-resistant stability and compressive strength; the compression strength of the basalt macadam is high; the coarse aggregate is prepared from the ceramsite, the granite macadam and the basalt macadam in a specific mass ratio range, so that the structural strength of the heat-insulation concrete is ensured, and the heat-resistance stability of the heat-insulation concrete is improved. Therefore, the compression strength of the test block 5 is higher than that of the test block 4, and the heat insulation performance of the test block 5 is better than that of the test block 4.

The vermiculite powder adopted by the test block 7 is prepared by a specific preparation method, the vermiculite adopted by the test block 6 is directly prepared by crushing the vermiculite by a crusher, the test block 16 does not adopt the vermiculite powder, but the data in the table 3 can show that the compression strength of the test block 16 is smaller than that of the test block 6, and the heat conductivity coefficient of the test block 16 is higher than that of the test block 6; the compression resistance and the heat insulation performance of the test block 6 are inferior to those of the test block 7. The modified vermiculite powder has stronger adsorption capacity, a large number of alumina particles are embedded between the lamella of the expanded vermiculite, the heat conductivity coefficient of the expanded vermiculite is reduced, the specific lamella structure of the expanded vermiculite has heat flow reflection capacity, the pore volume of the interlayer pores of the modified expanded vermiculite is reduced, the convection heat transfer path is blocked, and the heat insulation performance of the heat insulation concrete is further enhanced; meanwhile, a large number of uniform nano micropores are formed among the modified vermiculite layers, so that the compressive strength of the heat insulation concrete is increased.

The test block 17 adopts the medical stone powder to replace the vermiculite powder, although the medical stone powder and the vermiculite powder have adsorption performance, as can be seen from the table 3, the compression strength of the test block 17 is only 46Mpa, and the compression strength of the test block 14 reaches 87Mpa, so that the compression strength and the heat insulation performance of the heat insulation concrete are improved greatly by the medical stone powder, and the water absorption rate of the heat insulation concrete is increased and the impermeability is reduced easily when the medical stone powder is added into the heat insulation concrete.

The raw materials of the test block 14 adopt specific mass parts of all components, and the prepared heat insulation concrete has good compressive strength and heat insulation performance.

The test block 18 is a concrete prepared by expanded vermiculite powder disclosed at present, the concrete is tested according to the experiment 1-2, the compressive strength obtained by the test is lower than the compressive strength of the application, and the data in the table 3 show that the impermeability and the heat insulation capability of the test block 18 are lower than the impermeability and the heat insulation capability of the application, so that the concrete prepared by compounding different components and different mass parts in the test block 18 has lower compressive performance, impermeability and heat insulation performance than the compressive performance, impermeability and heat insulation performance of the application although the vermiculite powder is adopted for preparing the concrete.

The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. The heat insulation concrete is characterized in that: the feed is prepared from the following raw materials in parts by mass:

cement 150-280 parts

320 portions of coal ash and 430 portions

200 portions and 300 portions of coarse aggregate

River sand 350-420 parts

100 portions of vermiculite powder and 120 portions of

30-50 parts of aluminum powder

50-80 parts of fiber

10-20 parts of water reducing agent

80-140 parts of water.

2. The heat insulating concrete according to claim 1, wherein: also comprises 80-130 parts of hollow glass microspheres by mass.

3. The heat insulating concrete according to claim 2, wherein: the average particle fineness of the hollow glass beads is 0.02-0.05 mm.

4. The heat insulating concrete according to claim 1, wherein: the vermiculite powder is modified vermiculite powder, and the preparation method of the modified vermiculite powder comprises the following steps:

preparing raw materials: 10-20ml of aluminum sulfate solution is prepared for each gram of expanded vermiculite, and the mass ratio of the urea to Al3+ in the aluminum sulfate solution is (8-15): 1, the volume ratio of concentrated sulfuric acid to aluminum sulfate solution is 1: (400-500);

5. The heat insulating concrete according to claim 4, wherein: the concentration of the aluminum sulfate solution is 0.05-0.5 mol/L.

6. The heat insulating concrete according to claim 4, wherein: the average particle fineness range of the modified vermiculite powder is 0.06-0.075 mm.

7. The heat insulating concrete according to claim 1, wherein: the coarse aggregate is prepared from ceramsite, granite macadam and basalt macadam in a mass ratio of 1: and (2-3) 1.

8. The heat insulating concrete according to claim 1, wherein: the fiber is polypropylene fiber or basalt fiber.

9. The heat insulating concrete according to claim 1, wherein: the fiber is prepared from polypropylene fiber and basalt fiber in a mass ratio of (1-2): 1, in a mixture of the components.

10. A heat insulating concrete according to any one of claims 1 to 9, wherein: the feed is prepared from the following raw materials in parts by mass: