CN115504754A

CN115504754A - Steel pipe concrete based on solid waste expansion and preparation method thereof

Info

Publication number: CN115504754A
Application number: CN202211277101.4A
Authority: CN
Inventors: 马梦阳; 龙勇; 高立强; 陈露一; 欧阳华林; 舒健健; 周毅; 侍刚; 彭旭民
Original assignee: China Railway Major Bridge Engineering Group Co Ltd MBEC; China Railway Bridge Science Research Institute Ltd
Current assignee: China Railway Major Bridge Engineering Group Co Ltd MBEC; China Railway Bridge Science Research Institute Ltd
Priority date: 2022-10-18
Filing date: 2022-10-18
Publication date: 2022-12-23
Anticipated expiration: 2042-10-18
Also published as: CN115504754B

Abstract

The application relates to concrete filled steel tube based on solid waste expansion and a preparation method thereof, and the concrete filled steel tube comprises the following raw materials in parts by mass: 300 to 500 portions of cement, 150 to 250 portions of solid waste expanded rubber material, 5 to 15 portions of admixture, 500 to 900 portions of fine aggregate and 900 to 1300 portions of coarse aggregate; wherein the solid waste expanded glue comprises nickel slag, mineral powder, fly ash, semi-hydrated phosphogypsum and dihydrate phosphogypsum. The concrete filled steel tube prepared by adopting the expansion solid waste rubber material has good pumpability, low temperature rise, stable increase of expansion rate along with age, strong cohesive force between concrete and steel tube, and great use of solid waste material, is environment-friendly and has low cost.

Description

Steel pipe concrete based on solid waste expansion and preparation method thereof

Technical Field

The application relates to the technical field of building materials, in particular to concrete filled steel tubes based on solid waste expansion and a preparation method thereof.

Background

The ultra-high-rise steel pipe concrete structure requires that the concrete has good pumping performance, bleeding resistance and micro-expansion performance, the high strength of the concrete, the micro-expansion performance and the working performance are mutually influenced and restricted, and the core concrete is difficult to cause the steel pipe concrete to be voided due to later-stage curing difficulty; the large downward fall of concrete pouring is easy to cause segregation and the like. In addition, the structural section of the ultra-high structure is large in size, the deformation of the structure is influenced by the temperature change in the concrete hydration process, the concrete hydration temperature is required to be raised, and corresponding technical measures are required to be taken in the construction process to ensure the structural safety. Therefore, the research and development of the ultra-high-range concrete filled steel tube preparation technology has important significance and value.

With the rapid development of the building industry, natural resources for concrete production are increasingly reduced, the price of the ship is also increased, and how to realize the green development of the ultra-high steel tube concrete is a necessary way.

In the related technology, the ultrahigh-strength self-compacting micro-expansion steel pipe concrete mainly comprising cement and fly ash, an expanding agent, machine-made sand, broken stone, a shrinkage reducing functional material, an additive, water and copper-plated short and fine steel fibers is disclosed, mainly comprising natural resources and synthetic products, and not meeting the policies of green development and 'double carbon';

in addition, the solid waste steel pipe concrete containing the waste incineration fly ash is disclosed, steel slag and the waste incineration fly ash are mainly used as green expansion materials, however, the steel slag needs to be subjected to complex pretreatment and complicated procedures, and the compressive strength of the concrete is still not enough to meet the requirement of the ultra-high-grade steel pipe concrete on high strength.

Disclosure of Invention

The embodiment of the application provides concrete-filled steel tubes based on solid waste expansion and a preparation method thereof, and aims to solve the problem that concrete for steel tubes in the related technology is insufficient in compressive strength or does not accord with 'green' development.

The technical scheme provided by the application is as follows:

in a first aspect, the application provides a concrete filled steel tube based on solid waste expansion, which comprises the following raw materials in parts by mass:

300 to 500 portions of cement, 150 to 250 portions of solid waste expanded rubber material, 5 to 15 portions of admixture, 500 to 900 portions of fine aggregate and 900 to 1300 portions of coarse aggregate;

wherein the solid waste expanded glue comprises nickel slag, mineral powder, fly ash, semi-hydrated phosphogypsum and dihydrate phosphogypsum.

In some embodiments, the weight ratio of the nickel slag, the mineral powder, the fly ash, the phosphogypsum hemihydrate to the phosphogypsum dihydrate is 1: (0.2-0.5): (0.1-0.2): (0.2-0.4): (0.2-0.4).

In some embodiments, the admixture includes a polycarboxylate water reducer, a defoamer, and an air entraining agent.

In some embodiments, the mass ratio of the polycarboxylate water reducer, the defoamer and the air entraining agent is 100: (0.03-0.012): (0.002-0.007).

In some embodiments, the fine aggregate comprises iron tailings sand.

And/or the coarse aggregate comprises recycled aggregate and graded crushed stone.

In some embodiments, the mass ratio of the recycled aggregate to the graded broken stones in the coarse aggregate is 1 (3-5).

In some embodiments, the iron tailings sand has a fineness modulus of 2.3 to 3.0 and a thermal conductivity of 1.6 to 2.0W/(m · K);

and/or the recycled aggregate has a water absorption of 4-6%, a crushing value of less than or equal to 20% and a continuous gradation of 5-20mm;

and/or the continuous gradation of the graded crushed stones is 5-20mm.

In some embodiments, the nickel slag is blast furnace nickel slag, the nickel slag has a median particle size of 6-8 μm and Al ₂ O ₃ The content is more than or equal to 20 percent.

And/or the mineral powder is S95-grade mineral powder, and the specific surface area of the mineral powder is more than or equal to 400m ² /kg；

And/or the fly ash is I-grade fly ash;

and/or the cement is portland cement.

In a second aspect, the application also provides a preparation method of the concrete filled steel tube based on solid waste expansion, which comprises the following steps:

1) And stirring the cement, the solid waste expansion rubber material, the additive, the fine aggregate, the coarse aggregate and the water in a stirrer according to the proportion to obtain the concrete filled steel tube based on the solid waste expansion.

In some embodiments, the step 1) further comprises the steps of:

soaking the recycled aggregate in water for 20-30 h, taking out, and centrifuging by using a centrifuge, wherein the centrifugation radius is 8-12 cm, the centrifugation speed is 1500-2500 rpm, and the centrifugation time is 5-15 min to obtain saturated dried recycled aggregate;

and mixing the saturated dry recycled aggregate and the graded crushed stones according to a ratio to obtain the coarse aggregate.

The beneficial effect that technical scheme that this application provided brought includes:

(1) Common industrial solid waste materials such as nickel slag, mineral powder, fly ash, semi-hydrated phosphogypsum, dihydrate phosphogypsum and the like are used as expansion glue materials, so that the use of natural materials is reduced, and the requirement of the directive suggestion of fourteen five of the national development committee on the green development of building materials is met;

(2) The nickel slag, the mineral powder and the fly ash are all high-alumina slag, wherein the active Al is ₂ O ₃ Hydrogen generated by hydration with cementThe calcium oxide reacts to form hydrated calcium aluminate, and then sulfate ions provided by the phosphogypsum can react with the hydrated calcium aluminate to form acicular ettringite to compensate early shrinkage of the concrete. The spherical fly ash particles can improve the flowing property of concrete, and in addition, the phosphogypsum also has a good excitation effect on nickel slag, mineral powder and fly ash, and can improve the hydration activity of the nickel slag, the mineral powder and the fly ash under the combined action of an alkaline environment formed by cement, so that calcium silicate hydrate gel, hydrotalcite-like compound and other products are formed to improve the strength of the concrete. In addition, hydration of the nickel slag, the mineral powder and the fly ash is a low hydration heat release process, so that the temperature rise of concrete is reduced, and the temperature rise cracking degree is controlled;

(3) Phosphorus, fluorine and other impurities in the phosphogypsum dihydrate can block the progress of hydration reaction, so that a retarding effect is achieved, the phosphogypsum hemihydrate is used for replacing part of the phosphogypsum dihydrate to adjust the setting time of the concrete under the action of a mineral admixture with low activity, the setting time of the concrete is adjusted by quickly generating a needle-bar-shaped structure of the phosphogypsum hemihydrate and water, the regulation and control of the performance of the concrete are facilitated, the influence rule of the phosphogypsum hemihydrate and the phosphogypsum dihydrate on the expansion rate of the concrete is similar, and the expansion rate of the concrete cannot be greatly influenced even if the phosphogypsum hemihydrate and the phosphogypsum dihydrate are partially replaced with each other.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application, and it is obvious that the described embodiments are part of the embodiments of the present application, but not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making creative efforts shall fall within the protection scope of the present application.

In a first aspect, an embodiment of the present application provides a solid waste expansion-based concrete filled steel tube, which includes the following raw materials, by mass:

The solid waste expansion glue material is selected from common solid wastes in the metallurgical industry and the phosphogypsum production industry, is beneficial to relieving the problem of large accumulation of the current bulk solid wastes in China, promotes the recycling of wastes, and meets the requirement of green development.

The applicant obtains the solid waste expanded rubber material composition with excellent performance by optimizing the solid waste, wherein the nickel slag, the mineral powder and the fly ash are all high-aluminum slag, and the active Al in the high-aluminum slag ₂ O ₃ The calcium aluminate hydrate is generated by the reaction with calcium hydroxide generated by cement hydration, and then sulfate ions provided by phosphogypsum can react with the calcium aluminate hydrate to generate ettringite with a needle-shaped structure to compensate the early shrinkage of concrete;

the fly ash spherical particles can improve the flowing property of concrete and improve the pumpability of the concrete;

in addition, the coal ash and the phosphogypsum also generate good excitation effect on the nickel slag, the mineral powder and the coal ash, and can improve the hydration activity of the nickel slag, the mineral powder and the coal ash under the combined action of an alkaline environment formed by cement, so that calcium silicate hydrate gel, hydrotalcite-like compound and other products are formed to improve the strength of concrete;

hydration of the nickel slag, the mineral powder and the fly ash is a low hydration heat release process, which is beneficial to reducing the temperature rise of concrete and controlling the cracking degree of the temperature rise;

phosphorus, fluorine and other impurities in the dihydrate phosphogypsum can hinder the hydration reaction, so that the slow setting effect is realized, the dihydrate phosphogypsum can act together with a mineral admixture with low activity, the setting time of the concrete is overlong, the hemihydrate phosphogypsum is used for replacing part of the dihydrate phosphogypsum, the setting time of the concrete is adjusted by quickly generating a needle-rod-shaped structure of the dihydrate phosphogypsum through the hemihydrate phosphogypsum and water, and the regulation and control of the performance of the concrete are facilitated.

Specifically, the water-cement ratio of the concrete filled steel tube system based on solid waste expansion provided by the embodiment of the application is 0.24-0.45.

In some embodiments, the mass ratio of the nickel slag, the mineral powder, the fly ash, the phosphogypsum hemihydrate to the phosphogypsum dihydrate is 1: (0.2-0.5): (0.1-0.2): (0.2-0.4): (0.2-0.4).

In order to meet the requirements of the ultra-high-rise steel pipe on the high strength and the micro-expansion performance of the concrete, the inventor improves and adjusts the existing solid waste rubber material, can effectively improve the pumpability of the concrete, reduce the temperature rise of the concrete, compensate the early shrinkage of the concrete, and solve the problem of uneven heat transfer inside the concrete. It should be noted that the strength, expansibility, temperature rise, pumpability, etc. of the concrete are affected by the components of the solid waste expansion glue, and the selection and proportion of any one of the raw materials of the nickel slag, the mineral powder, the fly ash, the semi-hydrated phosphogypsum and the dihydrate phosphogypsum are changed, so that the strength, expansibility, temperature rise, pumpability, etc. of the obtained concrete are out of the range required by the embodiment.

The main component of the phosphogypsum hemihydrate is CaSO ₄ ·0.5H ₂ O; the main component of the dihydrate phosphogypsum is CaSO ₄ ·2H ₂ O。

According to the method, the high-efficiency polycarboxylate water reducer, the defoaming agent and the air entraining agent are compounded, so that the problems that the bubble content is high and the bubble size is difficult to control caused by the polycarboxylate water reducer can be solved, the gas content of newly-mixed concrete filled steel tubes is controlled within the range of 2% -3%, the concrete has good initial flow performance, the pumpability of the concrete is improved, and the problem of 'void' caused by bubbles is avoided.

In some embodiments, the fine aggregate comprises iron tailings; and/or the coarse aggregate comprises recycled aggregate and graded broken stones.

The iron tailing sand has high heat conductivity coefficient, effectively improves the heat conduction efficiency of concrete, reduces the temperature difference between the core part and other parts of the concrete, and is beneficial to improving the cracking problem caused by uneven temperature inside the concrete.

In some embodiments, the mass ratio of the recycled aggregate to the graded crushed stone in the coarse aggregate is 1 (3-5).

The recycled aggregate has water absorption much higher than that of the traditional aggregate, and can improve the problems of self-drying effect in concrete and insufficient expansion rate of the expanded solid waste rubber material in the middle and later periods through later-period water release.

Specifically, the recycled aggregate can be selected from recycled aggregates commonly used in the field, and the recycled aggregate is particles with the particle size of more than 4.75mm, which are prepared by crushing, screening and other procedures of waste concrete, mortar, stone, tiles and the like in construction waste and mixing according to a certain proportion.

In some embodiments, the iron tailings sand has a fineness modulus of 2.3 to 3.0 and a thermal conductivity of 1.6 to 2.0W/(m.K).

In some embodiments, the recycled aggregate has a water absorption of 4% to 6%, a crush value of 20% or less, and a continuous gradation of 5 to 20mm; and/or the continuous gradation of the graded crushed stones is 5-20mm.

In some embodiments, the nickel slag is blast furnace nickel slag, the nickel slag has a median particle size of 6-8 μm and Al ₂ O ₃ The content is more than or equal to 20 percent; and/or the mineral powder is S95-grade mineral powder, and the specific surface area of the mineral powder is more than or equal to 400m ² Per kg; and/or the fly ash is I-grade fly ash.

Preferably, the water demand ratio of the fly ash is less than or equal to 100, and the activity index is more than or equal to 70%.

In particular, the graded crushed stone may be selected from granite crushed stone or pebbles.

In some embodiments, the cement is portland cement.

In a preferred embodiment, the portland cement has a specific surface area of 350-500m ² /kg。

In some embodiments, the step 1) is preceded by the steps of:

101: soaking the recycled aggregate in water for 24 hours, taking out, and centrifuging by using a centrifuge, wherein the centrifugation radius is 8-12 cm, the centrifugation speed is 2000rpm, and the centrifugation time is 10min to obtain saturated dried recycled aggregate;

102: and mixing the saturated dry recycled aggregate and the graded crushed stones according to a ratio to obtain the coarse aggregate.

The recycled aggregate is saturated with water in advance, the recycled aggregate is in a saturated surface dry state by adopting a centrifugal method, and self-drying in the concrete and self-shrinkage cracking inhibition can be realized by releasing water in the later hardening period of the concrete.

The present application is further illustrated by the following specific examples.

Description of raw materials:

cement: huaxin P.I 42.5 cement;

mineral powder: s95 mineral powder produced by Zhuhai Yuyufeng iron and steel Limited company with a specific surface area of 494m ² /kg；

Fly ash: the grade I fly ash produced by Guangzhou Hengyun Enterprise group Limited company has water demand ratio of 98 percent and activity index of 78 percent;

semi-hydrated phosphogypsum and dihydrate phosphogypsum: the Hubei nationality;

polycarboxylic acid water reducing agent: wuhanhuaxuan KH-5 type high-performance polycarboxylic acid water reducing agent;

defoaming agent: the concrete defoamer comprises a Jiangsu Subo SBT-PXP (I) concrete defoamer;

air entraining agent: the Jiangsu Subo special GYQ-I concrete high-efficiency air entraining agent;

iron tailing sand: the fineness modulus is 2.6, and the heat conductivity coefficient is 1.7W/(m.K);

graded broken stone: guangxi Xindong mineral industry Co., ltd, the gradation is 5-20mm, the content of needle and sheet particles is 3.2%, and the crushing value is 9%;

recycled aggregate: the water absorption rate is 4-6%, the crushing value is less than or equal to 20%, and the continuous gradation is 5-20mm.

Example 1

This example illustrates the solid waste expansion based steel pipe concrete and the preparation method thereof disclosed in the present application, and the raw material composition is shown in table 1:

TABLE 1

The preparation process comprises the following steps:

101: treatment of recycled aggregate: after the recycled aggregate is saturated with water, the recycled aggregate is centrifugally treated to reach a saturated surface dry state, the water saturation rate is 6 percent, and the crushing value is 11 percent;

102: preparing an additive: compounding a polycarboxylate superplasticizer mother solution (solid content is 40%), a defoaming agent and an air entraining agent according to the mass ratio shown in the table 1, and diluting the mixture to a solid content of 25%;

103: preparing coarse aggregate: mixing the water-saturated recycled aggregate with the graded broken stones according to the mass ratio of 1;

104: preparing a solid waste expansion glue material: mixing nickel slag, mineral powder, fly ash, semi-hydrated phosphogypsum and dihydrate phosphogypsum in a mixer according to the mass ratio of 1;

105: preparing concrete filled steel tube: adding water into cement, solid waste expanded rubber materials, an additive, fine aggregates and coarse aggregates according to a mass ratio of 300.

Example 2

This example is used to illustrate the solid waste expansion-based steel tube concrete and the preparation method thereof disclosed in the present application, and the raw material composition is shown in table 2:

TABLE 2

The preparation process comprises the following steps:

102: preparing an additive: compounding a polycarboxylate superplasticizer mother liquor (solid content: 40%), a defoaming agent and an air entraining agent according to the mass ratio shown in the table 2, and diluting to solid content: 25%;

105: preparing concrete filled steel tube: adding water into cement, solid waste expanded rubber materials, an additive, fine aggregates and coarse aggregates according to a mass ratio of 400.

Example 3

This example illustrates the solid waste expansion based steel pipe concrete and the preparation method thereof disclosed in the present application, and the raw material composition is shown in table 3:

TABLE 3

102: preparing an additive: compounding a polycarboxylate superplasticizer mother liquor (solid content: 40%), a defoaming agent and an air entraining agent according to the mass ratio shown in the table 3, and diluting to solid content: 25%;

104: preparing a solid waste expansion glue material: mixing nickel slag, mineral powder, coal ash, semi-hydrated phosphogypsum and dihydrate phosphogypsum in a mixer according to the mass ratio of 1;

105: preparing concrete filled steel tube: adding water into cement, solid waste expansion glue materials, an additive, fine aggregates and coarse aggregates according to a mass ratio of 500.

Example 4

This example is used to illustrate the solid waste expansion-based steel tube concrete and the preparation method thereof disclosed in the present application, and the raw material composition is shown in table 4:

TABLE 4

102: preparing an additive: compounding a polycarboxylate superplasticizer mother solution (solid content is 40%), a defoaming agent and an air entraining agent according to the mass ratio shown in the table 4, and diluting the mixture to a solid content of 25%;

Example 5

This example illustrates the solid waste expansion based steel pipe concrete and the preparation method thereof disclosed in the present application, and the raw material composition is shown in table 5:

TABLE 5

102: preparing an additive: compounding a polycarboxylate superplasticizer mother liquor (solid content: 40%), a defoaming agent and an air entraining agent according to the mass ratio shown in the table 5, and diluting to solid content of 25%;

Example 6

This example illustrates the solid waste expansion based steel pipe concrete and the preparation method thereof disclosed in the present application, and the raw material composition is shown in table 6:

TABLE 6

102: preparing an additive: compounding a polycarboxylate superplasticizer mother liquor (solid content: 40%), a defoaming agent and an air entraining agent according to the mass ratio shown in the table 6, and diluting to solid content: 25%;

Comparative example 1

This comparative example is used for comparative illustration of the solid waste expansion based steel pipe concrete and the preparation method thereof disclosed in the present application, and the raw material composition is shown in table 7:

TABLE 7

102: preparing an additive: compounding a polycarboxylate superplasticizer mother solution (solid content is 40%), a defoaming agent and an air entraining agent according to the mass ratio shown in the table 7, and diluting the mixture to a solid content of 25%;

104: preparing a solid waste expansion glue material: mixing nickel slag, mineral powder, coal ash and semi-hydrated phosphogypsum in a mixer according to the mass ratio of 1;

Comparative example 2

This comparative example is used for comparative illustration of the solid waste expansion based steel pipe concrete and the preparation method thereof disclosed in the present application, and the raw material composition is shown in table 8:

TABLE 8

102: preparing an additive: compounding a polycarboxylate superplasticizer mother liquor (solid content: 40%), a defoaming agent and an air entraining agent according to the mass ratio shown in the table 8, and diluting to solid content: 25%;

104: preparing a solid waste expansion glue material: mixing nickel slag, mineral powder, fly ash and dihydrate phosphogypsum in a mixer according to the mass ratio of 1.2;

Performance testing

The following performance tests were carried out on the concretes prepared in examples 1-6 and comparative examples 1-2, the test results being filled in table 9:

(1) Slump/spread: the test is carried out according to GB/T50080-2016 standard of common concrete mixture performance test method.

(2) Compressive strength: the test is carried out according to GB/T50080-2016 standard of common concrete mixture performance test method.

(3) Sealing free expansion rate: the prepared concrete is poured into a steel cylinder with the embedded intelligent string type strain gauge arranged in advance, the size is phi 200mm multiplied by 400mm, and the volume deformation of the concrete is detected after 24 hours from pouring.

Note: in table 9, "S" represents example, e.g., "S1" represents example 1; "D" represents comparative example, e.g., "D1" represents comparative example 1".

TABLE 9

According to slump/expansion data in Table 9, it is shown that the concrete prepared by the scheme of the application in examples 1-6 has good working performance, and the air content of fresh concrete is effectively controlled to be 2-3%;

by combining the data of the embodiment 1 and the comparative examples 1-2, the concrete compounded with the nickel slag, the mineral powder, the fly ash, the semi-hydrated phosphogypsum and the dihydrate phosphogypsum in the embodiment 1 has higher compressive strength in 3 days, 7 days and 28 days compared with the comparative examples 1-2, and the data of the 60d sealing free expansion rate indicates that the concrete has good micro-expansibility, while the 60d sealing free expansion rate of the comparative examples 1-2 is less than 0, which indicates that the concrete has a shrinkage phenomenon, so that the solid waste expansion glue material can effectively improve the pumpability of the concrete, reduce the temperature rise of the concrete and compensate the early shrinkage of the concrete;

by combining the data of example 1 and examples 5-6, the ratio of the phosphogypsum hemihydrate to the phosphogypsum dihydrate in example 5 is too low, and the compressive strength monitored in 3 days and 7 days is lower than that of example 1, which indicates that the application can further effectively shorten the concrete setting time and improve the early strength of the concrete by controlling the ratio of the phosphogypsum hemihydrate to the phosphogypsum dihydrate within a proper range;

in example 6, the proportion of phosphogypsum hemihydrate to phosphogypsum dihydrate is too high, and the slump/expansibility data is lower than that of example 1, which shows that the working performance of the concrete is easily reduced due to the fact that the proportion of phosphogypsum hemihydrate is too high, so that the application can ensure the working performance of the concrete and improve the compressive strength by adjusting the proportion of phosphogypsum hemihydrate to phosphogypsum dihydrate within a proper range.

The above description is merely exemplary of the present application and is presented to enable those skilled in the art to understand and practice the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. The concrete filled steel tube based on solid waste expansion is characterized by comprising the following raw materials in parts by mass:

2. The solid waste expansion-based concrete filled steel tube according to claim 1, wherein the mass ratio of the nickel slag, the mineral powder, the fly ash, the phosphogypsum hemihydrate to the phosphogypsum dihydrate is 1: (0.2-0.5): (0.1-0.2): (0.2-0.4): (0.2-0.4).

3. The solid waste expansion-based steel tube concrete according to claim 1, wherein the admixture comprises a polycarboxylic acid water reducing agent, a defoaming agent and an air entraining agent.

4. The solid waste expansion-based steel tube concrete according to claim 3, wherein the mass ratio of the polycarboxylic acid water reducer to the defoaming agent to the air entraining agent is 100: (0.03-0.012): (0.002-0.007).

5. The solid waste expansion-based steel tube concrete according to claim 1, wherein the fine aggregate comprises iron tailings sand.

And/or the coarse aggregate comprises recycled aggregate and graded broken stones.

6. The solid waste expansion-based steel tube concrete according to claim 5, wherein the mass ratio of the recycled aggregate to the graded crushed stone in the coarse aggregate is 1 (3-5).

7. The solid waste expansion-based steel tube concrete according to claim 5, wherein the fineness modulus of the iron tailings sand is 2.3-3.0, and the thermal conductivity is 1.6-2.0W/(m-K);

and/or the continuous gradation of the graded crushed stones is 5-20mm.

8. The solid waste expansion-based steel tube concrete according to claim 1, wherein the nickel slag is blast furnace nickel slag, and the median particle size of the nickel slag is 6-8 μm, and Al is ₂ O ₃ The content is more than or equal to 20 percent;

And/or the fly ash is I-grade fly ash;

and/or the cement is portland cement.

9. The method for preparing concrete filled steel tube based on solid waste expansion according to any one of claims 1 to 8, comprising the steps of:

1): and stirring the cement, the solid waste expansion rubber material, the additive, the fine aggregate, the coarse aggregate and the water in a stirrer according to the proportion to obtain the concrete filled steel tube based on the solid waste expansion.

10. The method for preparing concrete filled steel tube based on solid waste expansion according to claim 9, wherein the step 1) is preceded by the following steps: