CN113605698A

CN113605698A - High-throwing self-compacting micro-expansion concrete-filled steel tube construction process

Info

Publication number: CN113605698A
Application number: CN202110515877.4A
Authority: CN
Inventors: 顾金戈; 徐佳能; 范晓晋; 胡锐; 刘春辉; 陈�胜; 廖榆; 倪汝贤; 孙靖宜; 卞越
Original assignee: China Huashi Enterprises Co Ltd
Current assignee: China Huashi Enterprises Co Ltd
Priority date: 2021-05-12
Filing date: 2021-05-12
Publication date: 2021-11-05

Abstract

The invention relates to the technical field of building construction, and discloses a high-throw self-compaction micro-expansion steel column concrete construction process which comprises three process modules, namely material blending, sample testing and construction operation; the process module material blending comprises the steps of material selection, proportioning design, test verification and the like; the process module sample test comprises the steps of steel column manufacturing, primary pouring, secondary pouring, maintenance test and the like; the construction operation of the process module comprises the steps of steel column improvement, pump concrete distribution, auxiliary vibration, cleaning and maintenance and the like. The construction method can effectively solve the construction difficulty of the steel pipe concrete, can avoid the quality defects of cavities, honeycombs and the like caused by the incapability of vibrating or insufficient vibration, greatly reduce the construction noise, can construct a plurality of layers of steel pipe columns at one time, accelerate the construction speed, ensure and improve the construction quality, has good economic and social benefits, and has great popularization value and wide application prospect.

Description

High-throwing self-compacting micro-expansion concrete-filled steel tube construction process

Technical Field

The invention relates to the technical field of building construction, in particular to a high-throw self-compaction micro-expansion concrete filled steel tube construction process.

Background

With the rapid development of building technology, the steel tube concrete is widely popularized and applied in high-rise buildings and large-span structural engineering. The Steel pipe Concrete structure (CFST) is a composite structure formed by filling Concrete in a Steel pipe, and can more effectively exert the respective advantages of two materials, namely Steel and Concrete, and overcome the defect that the Steel pipe structure is easy to bend. Compared with a steel structure, the CFST can save a large amount of steel, and has better fire resistance; compared with a concrete structure, the CFST can obtain larger building space, reduce the dead weight and the cement consumption, improve the anti-seismic performance and the like. The steel pipe concrete can utilize the synergistic bearing effect of two materials of the steel pipe and the concrete in the stress process, so that the steel pipe concrete has the characteristics of high bearing capacity, good plasticity and toughness, good fire resistance and earthquake resistance, good economic benefit and the like.

However, in the steel pipe concrete engineering, the concrete pouring amount is large, the pumping height is large, and the concrete is wrapped by the peripheral steel pipe, so that the pouring construction difficulty is quite large. The high-throwing self-compacting concrete has the characteristics of no segregation and no bleeding due to high fluidity, can automatically level and compact without vibration or auxiliary vibration, achieves the purpose of compacting the concrete by utilizing the kinetic energy generated when the concrete falls from a high position, can effectively solve the construction difficulty of the steel pipe concrete, can avoid the quality defects of cavities, honeycombs and the like caused by the incapability of vibration or insufficient vibration, greatly reduces the construction noise, accelerates the construction speed, ensures and improves the construction quality, and is one of the development directions of the steel pipe concrete construction methods.

However, the key technology of the steel pipe concrete composite material is to tightly combine the core concrete and the steel pipe wall, to obtain a reliable composite effect, to solve the problem of cooperativity of expansion and contraction and strength development, the continuous and stable expansion of the concrete in a closed state, the design and controllability of the expansion stress of the concrete-steel pipe wall, the preparation of the expanded concrete and the construction technology thereof.

Therefore, in the technical field of building construction, a technology capable of overcoming the respective technical difficulties and the combination of the high-throwing self-compacting concrete, the micro-expansive concrete and the steel column concrete is urgently needed, and the technology can be applied to the high-throwing self-compacting micro-expansive steel pipe concrete construction technology of high-rise buildings.

Disclosure of Invention

The invention overcomes the defects of the prior art, provides the technical barriers which can overcome the respective technical difficulties of high-throwing self-compacting concrete, micro-expansive concrete and steel column concrete and the combination of the three, and can be applied to the high-throwing self-compacting micro-expansive steel pipe concrete construction process of high-rise buildings.

The invention is realized by the following technical scheme:

the high-throwing self-compacting micro-expansion steel pipe concrete construction process comprises three process modules, namely material preparation, sample test and construction operation;

the process module I comprises the following steps of: A. material selection, B proportioning design and C test verification;

the sample test comprises the following steps: D. manufacturing a steel column, E, primary pouring, F, secondary pouring and G, maintaining and testing;

the construction operation comprises the following steps: H. steel column improvement, J pump concrete distribution, K auxiliary vibration, M cleaning and maintenance.

Further, in the step a, the material selection includes the following materials:

a1. cement: 42.5R ordinary Portland cement with the 28D compressive strength of 52MPa and qualified stability;

a2. fly ash: the grade I fly ash with the water requirement ratio of 92 percent and the screen residue of a 0.045mm sieve of 10.3 percent;

a3. silica fume: silica fume with the silica content of 94 percent and the activity index of 114 percent;

a4. swelling agent: the specific surface area is 255m²WG-CMA as three-expansion-source expansion agent with 0.025% of limited expansion rate in water of/kg and 7D;

a5. fine aggregate: medium sand with fineness modulus of 2.7 and stone powder content of 6 percent;

a6. coarse aggregate: 5-20 continuous gradation and 2.67g/cm apparent density³Crushed stone with the crushing index of 7 percent;

a7. pumping agent: the pumping agent special for the high-throwing self-compacting concrete has the solid content of 15.10 percent, the water reducing rate of 31 percent and the compressive strength of 199 percent.

Further, in the step B, in the proportioning design, the mass parts of the materials are as follows: 488.2-547.8 parts of cement, 29.7-36.3 parts of fly ash, 29.7-36.3 parts of silica fume, 32.4-39.6 parts of expanding agent, 733.5-896.5 parts of fine aggregate, 831.6-1016.4 parts of coarse aggregate and 15.12-18.48 parts of pumping aid.

Further, in the step c, test verification, the tested items include c1. development, c2. slump, c3.T500 development time, c4. rewinding time, c5. mixture segregation rate and c6.U type box height difference test.

Step D, in the manufacturing of the steel column, the specification of the steel column is 1200mm multiplied by 1600mm multiplied by 8000mm, and the wall thickness is 30 mm; step E, performing primary pouring in a pouring mode of four meters at the lower part of the steel column by adopting an automobile pump and a non-vibration mode; and F, performing secondary pouring by adopting an automobile pump and micro-vibration mode aiming at a pouring mode of four meters above the steel column.

Further, step G, in the maintenance test, covering the top opening surface, initially setting, napping and watering, detecting the blank sound and carrying out ultrasonic detection by D7, detecting the blank sound and carrying out ultrasonic detection by D28, cutting at a fixed point by D135, sampling and actually measuring.

And step H, in the steel column improvement, the inner side wall of the steel column is additionally provided with a stud, and/or the horizontal partition plate is additionally provided with an air hole.

Further, in the step j, the pump concrete distribution comprises the following steps:

j1. testing the expansion degree and the slump degree before pumping;

j2. laying out

The high-pressure pump pipe of (1);

j3. four meters of non-vibration high-pressure pump pipes at the lower part of the steel column are uniformly distributed.

And further, in the step K, in the auxiliary vibration, for the colleagues that four meters of the upper part of the steel column are distributed on the pump concrete, a vibration rod is inserted into the concrete of the lower layer for auxiliary vibration by 5-10cm, vibration points are uniformly arranged according to a quincunx shape, the vibration rod moves point by point, the vibration rod is inserted quickly and pulled slowly, the vibration time of each point is 5-10 seconds, the vibration rod does not obviously descend until the surface of the concrete is flush, and no air bubble appears.

Further, in the step M, cleaning and maintaining, the method comprises the following steps:

m1. pouring and distributing materials until the distance between the top of the concrete and the opening at the top of the steel column is 600mm, stopping pouring, taking out concrete slurry with the thickness of 100mm at the upper part, and scratching the top by using a tool;

and m2, pouring clear water with the thickness of 200mm on the top of the concrete after initial setting for maintenance, and additionally arranging a cover at the opening at the top of the steel column.

And m3, before the upper section of steel column is installed, taking out the residual clear water on the top of the concrete, wiping the top of the concrete, and removing the concrete grout adhered to the wall of the pipe.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. the steel tube concrete can more effectively exert the respective advantages of steel and concrete, and overcomes the defect that a steel tube structure is easy to bend.

2. It can save a great deal of steel, has better fire resistance, can obtain larger building space, reduces dead weight and cement consumption, and improves earthquake resistance.

3. The steel pipe concrete does not need a template and a formwork system, can save a large amount of wood, and has good environmental protection significance.

4. The high-throwing self-compacting concrete achieves the purpose of compacting the concrete by utilizing the kinetic energy generated when the concrete falls from a high position, can effectively solve the construction difficulty of the concrete filled steel tube, can avoid the quality defects of cavities, honeycombs and the like caused by incapability of vibrating or insufficient vibration, and greatly reduces the construction noise.

5. The construction method can be used for one-step construction of a multilayer steel pipe column, quickens the construction speed, ensures and improves the construction quality, has good economic and social benefits, and has great popularization value and wide application prospect.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

FIG. 1 is a schematic structural view of a test steel column of the present invention;

FIG. 2 is a schematic view of a steel column sampling site according to the present invention;

FIG. 3 is a schematic view of the sampling point location at A of the present invention;

FIG. 4 is a schematic view of the sampling point location at B of the present invention;

FIG. 5 is a schematic view of the sampling point location at C of the present invention;

FIG. 6 is a schematic view of the sampling point location at D of the present invention;

FIG. 7 is a schematic view of the sampling point location at E of the present invention;

FIG. 8 is a schematic view of the sampling point location at F according to the present invention;

FIG. 9 is a schematic view of the sampling point location at G of the present invention;

FIG. 10 is a schematic view of the sampling point location at H according to the present invention;

FIG. 11 is a schematic view of the sampling point location at I of the present invention;

FIG. 12 is a schematic view of the sampling point location at J according to the present invention;

FIG. 13 is a schematic view of the sampling point location at K according to the present invention;

FIG. 14 is a schematic view of the sampling point location at L of the present invention;

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.

The high-throwing self-compacting micro-expansion steel column concrete construction process comprises three process modules, namely material blending, sample testing and construction operation.

The process module I is used for blending materials and comprises the following steps: A. material selection, B proportioning design and C test verification;

step A, material selection, which comprises the following materials:

And B, in the proportioning design, the mass parts of the materials are as follows: 488.2-547.8 parts of cement, 29.7-36.3 parts of fly ash, 29.7-36.3 parts of silica fume, 32.4-39.6 parts of expanding agent, 733.5-896.5 parts of fine aggregate, 831.6-1016.4 parts of coarse aggregate and 15.12-18.48 parts of pumping aid.

Step C, in test verification, the tested items comprise c1. expansion degree, c2. slump, c3.T500 expansion time, c4. cylinder-reversing time, c5. mixture segregation rate and c6. U-shaped box height difference test.

TABLE 1 Material ratio (kg/m)³)

Numbering	Cement	Fly ash	Silica fume	Expanding agent	Fine aggregate	Coarse aggregate	Additive agent
								1	498	33	33	36	815	924	16.8
2	463	32	32	34	837	948	15.7
								3	496	34	34	36	776	956	16.8
4	496	34	34	36	848	884	16.8
								5	496	34	34	36	815	924	15.0

The specific components of five examples of the material proportioning test are shown in the table (table 1), and the test results of the tests of the five examples are shown in the table (table 2).

TABLE 2 test results

As can be seen from tables 1 and 2, when the concrete cementing material mixing amount is different, as shown in the numbers 1 and 2, the concrete compressive strength is greatly influenced, so that a reasonable cementing material dosage needs to be selected, and the dosage of the cementing material is determined to be 600 kg/m 3; when the sand rate of the concrete is different, as shown in the number 1, the number 3 and the number 4, the flowing performance of the concrete is greatly influenced, when the sand rate is too small, the phenomena of exposed aggregate and poor wrapping performance are easy to occur, and when the sand rate is too low, the phenomena of reduced concrete strength, poor segregation and poor clearance permeability are caused, so that a reasonable sand rate is necessary to be selected; when the mixing amount of the concrete admixture is different, the workability, particularly the fluidity of the concrete is greatly influenced, and as shown in the No. 5, the self-compacting concrete has poor fluidity, serious slump loss with time and poor clearance permeability, so that a reasonable mixing amount of the admixture is selected.

step D, in the manufacturing of the steel column, the specification of the steel column is 1200mm multiplied by 1600mm multiplied by 8000mm, and the wall thickness is 30 mm; step E, performing primary pouring in a pouring mode of four meters at the lower part of the steel column by adopting an automobile pump and a non-vibration mode;

and F, performing secondary pouring by adopting an automobile pump and micro-vibration mode aiming at a pouring mode of four meters above the steel column.

And G, in the maintenance test, covering the open surface at the top, initially setting, napping and irrigating, performing D7 knocking detection on the blank sound and performing ultrasonic detection, performing D28 knocking detection on the blank sound and performing ultrasonic detection, and performing D135 fixed-point cutting, sampling and actual measurement.

And H, in the steel column improvement, the inner side wall of the steel column is additionally provided with a stud, and/or the horizontal partition plate is additionally provided with an air hole.

Step J, in the pump concrete distribution, the method comprises the following steps: j1. testing the expansion degree and the slump degree before pumping; j2. laying out

The high-pressure pump pipe of (1); j3. four meters of non-vibration high-pressure pump pipes at the lower part of the steel column are uniformly distributed.

And step K, in auxiliary vibration, aiming at the same time that four meters of the upper part of the steel column are distributed on the concrete of the pump, inserting a vibration rod into the concrete of the lower layer for 5-10cm for auxiliary vibration, uniformly arranging vibration points according to a quincunx shape, moving point by point, quickly inserting and slowly pulling, wherein the vibration time of each point is 5-10 seconds, the concrete does not obviously descend until the surface of the concrete is flush, and no air bubble appears.

Step M, in the cleaning and maintenance, the method comprises the following sub-steps: m1. pouring and distributing materials until the distance between the top of the concrete and the opening at the top of the steel column is 600mm, stopping pouring, taking out concrete slurry with the thickness of 100mm at the upper part, and scratching the top by using a tool; m2, pouring clear water with the thickness of 200mm on the top of the concrete for curing after initial setting, and arranging a cover on the opening at the top of the steel column. m3, before the steel column is mounted, the residual clear water on the top of the concrete is contained, the top of the concrete is wiped dry, and the concrete grout adhered to the wall of the pipe is removed.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

It will be understood that the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for convenience in describing the invention, and do not indicate or imply that the components or mechanisms so referred to must be in a particular orientation, constructed and operated in a particular orientation, and thus are not to be considered as limiting the invention.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely preferred embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. The high-throwing self-compacting micro-expansion steel column concrete construction process is characterized by comprising three process modules, namely material preparation, sample test and construction operation, wherein the three process modules comprise a first process module, a second process module, a third process module and a third process module;

2. The construction process for the concrete of the high-throw self-compacting micro-expansion steel column according to claim 1, wherein the material selection in the step A comprises the following materials:

3. The high-throwing self-compacting micro-expansion steel column concrete construction process according to claim 2, wherein in the step B, the material parts by mass are as follows: 488.2-547.8 parts of cement, 29.7-36.3 parts of fly ash, 29.7-36.3 parts of silica fume, 32.4-39.6 parts of expanding agent, 733.5-896.5 parts of fine aggregate, 831.6-1016.4 parts of coarse aggregate and 15.12-18.48 parts of pumping aid.

4. The construction process of high-throw self-compacting micro-expansion steel column concrete as claimed in claim 3, wherein in the step C, test verification, the tested items comprise c1. expansion, c2. slump, c3.T500 development time, c4. cylinder-falling time, c5. mixture segregation rate and c6.U box height difference test.

5. The construction process for the concrete of the high-throw self-compacting micro-expansion steel column as claimed in claim 1, wherein in the step D, the steel column is made into a specification of 1200mm × 1600mm × 8000mm, and the wall thickness is 30 mm; step E, performing primary pouring in a pouring mode of four meters at the lower part of the steel column by adopting an automobile pump and a non-vibration mode; and F, performing secondary pouring by adopting an automobile pump and micro-vibration mode aiming at a pouring mode of four meters above the steel column.

6. The construction process for the high-throw self-compacting micro-expansion steel column concrete according to claim 5, wherein in the step G, maintenance test comprises top open surface covering, initial setting, napping and watering, D7 knocking, detecting and ultrasonically detecting, D28 knocking, detecting and ultrasonically detecting, D135 fixed-point cutting, sampling and actual measurement.

7. The construction process for high-throw self-compacting micro-expansion steel column concrete according to claim 1, wherein the step H. steel column improvement comprises additionally arranging studs on the inner side wall of the steel column and/or additionally arranging air holes on the horizontal partition plate.

8. The construction process for the high-throw self-compacting micro-expansion steel column concrete according to claim 7, wherein the step J of pump concrete distribution comprises the following steps:

j1. testing the expansion degree and the slump degree before pumping;

j2. laying out

The high-pressure pump pipe of (1);

9. The construction process for the high-throw self-compacting micro-expansion steel column concrete according to claim 8, characterized in that in the step K, in the auxiliary vibration, for the colleagues that the concrete is distributed on the pump four meters above the steel column, a vibration rod is inserted into the concrete on the lower layer for 5-10cm for auxiliary vibration, vibration points are uniformly arranged according to a quincunx shape, the vibration points move point by point, are rapidly inserted and slowly pulled, and each vibration time lasts for 5-10 seconds, so that the concrete does not obviously descend until the surface of the concrete is flush, and no air bubbles appear.

10. The construction process for the high-throw self-compacting micro-expansion steel column concrete according to claim 9, wherein the step M of cleaning and maintaining comprises the following steps: