Precast concrete column with built-in recycled components and construction method thereof

Abstract

The present invention discloses a precast concrete column with built-in recycled components and a construction method thereof. The precast concrete column includes recycled components, column longitudinal reinforcement, spiral stirrups, ordinary or composite stirrups, a first connector, a second connector, new concrete and a grouting sleeve; the recycled components include old stirrups, old longitudinal reinforcement and old concrete. The present invention directly utilizes old beam-type components and old column-type components instead of crushing the old concrete therein into recycled blocks or recycled aggregates for reuse, which greatly simplifies the processing procedures, significantly improves the recycling rate of old concrete, significantly reduces the amount of new concrete and the corresponding cement, and has a significant energy-saving and carbon-reducing effect. At the same time, the present invention also provides a steel bar connector, so that the old stirrups have an additional lateral restraint effect on the column longitudinal reinforcement and the old longitudinal reinforcement and the column longitudinal reinforcement are synergistically stressed, thereby appropriately reducing the amount of spiral stirrups and column longitudinal reinforcement in the precast concrete column, which has obvious economic benefits.

Description

Technical Field

[0001] The invention relates to the technical field of recycling waste concrete, and in particular to a prefabricated concrete column with built-in recycled components and a construction method thereof. Background Art

[0002] With the rapid development of urban construction and the orderly advancement of urban renewal in my country, how to reuse the demolished old concrete components in a green and efficient manner has become a focus of increasing social attention. At present, the common practice is to crush the old concrete in the old concrete components into small-scale recycled aggregates or recycled blocks, and then add cement and other cementitious materials to prepare recycled aggregate concrete, or mix with new concrete to form recycled block concrete. However, in addition to the cumbersome process of crushing, it also produces a lot of energy consumption and difficult-to-use powder, which significantly reduces the recycling rate of old concrete; and the preparation of recycled aggregate concrete consumes a lot of cement. The proportion of new concrete in recycled block concrete is as high as about 70%, and the preparation of these new concretes also consumes a lot of cement. Since cement production produces a lot of CO2, the carbon emission reduction effect of the above current practices needs to be further improved. At the same time, the old steel bars recovered from the old concrete components during the crushing process also need to go through complex processes such as smelting before they can be reused as resources. These complex processes also consume a lot of energy and emit a lot of CO2, and the carbon emission reduction effect is not obvious. In summary, the recycling and reuse strategy of old concrete components needs to be further improved. Therefore, if old concrete components can be directly used in the production of new components without crushing, the above problems will undoubtedly be greatly alleviated. However, there is currently no precedent for how to simply and efficiently use old concrete components in the production of new components.

[0003] Precast concrete components are widely used in engineering construction due to their fast construction speed, high degree of industrialization and low environmental pollution. Columns are important vertical load-bearing components in building structures. In the production process of precast concrete columns, if the recycled components obtained after simple treatment of old concrete components can be directly cast inside the new precast concrete columns, it is undoubtedly an effective way to realize the direct utilization of old concrete components. Summary of the invention

[0004] At present, the existing technology cannot realize the recycling and reuse of old beam-type components and old column-type components at the component level. The present invention provides a precast concrete column with built-in recycled components and a construction method thereof, and is the first to propose an effective countermeasure for recycling and reuse of old beam-type components and old column-type components as a whole in precast concrete columns, which has a significant carbon emission reduction effect.

[0005] In order to achieve the purpose of the present invention, the present invention provides a precast concrete column with a built-in recycled component, comprising a recycled component, a column longitudinal reinforcement, a spiral stirrup, a common or composite stirrup, a first connecting piece, a second connecting piece, new concrete and a grouting sleeve;

[0006] The recycled component is surrounded by new concrete, the recycled component includes old stirrups, old longitudinal bars and old concrete, the height and cross-sectional width of the recycled component are respectively smaller than the height and cross-sectional width of the precast concrete column, and the volume of the recycled component is not less than 40% of the volume of the precast concrete column;

[0007] The column longitudinal reinforcement is located in the new concrete;

[0008] The grouting sleeve is located below the regeneration component;

[0009] The setting range of the common or composite stirrups is the area where the grouting sleeve is located;

[0010] The setting range of the spiral stirrup is the area where the non-grouting sleeve is located;

[0011] The first connecting member is made of steel bars and is used to connect the old stirrups and the column longitudinal bars. The first connecting member is set in the area where the regenerated components are located.

[0012] The second connecting member is made of steel bars and is used to connect the old longitudinal bars and the column longitudinal bars; the second connecting member is set within the upper longitudinal range of 0-500mm and the lower longitudinal range of 0-500mm in the area where the regenerated component is located;

[0013] Except for the inside of the grouting sleeve, new concrete is poured around the grouting sleeve and on the top, bottom and around the recycled component. The new concrete is natural aggregate concrete or recycled aggregate concrete with a maximum particle size of coarse aggregate not greater than 20 mm, or recycled aggregate concrete containing recycled sand from engineering slag.

[0014] Furthermore, the net distance between the lower surface of the regeneration component and the grouting sleeve is 50-100 mm.

[0015] Furthermore, the cross-sectional width of the recycled component is at least 150 mm smaller than the cross-sectional width of the precast concrete column.

[0016] Furthermore, the recycled component is obtained by removing the stirrup protective layer from the old concrete component obtained by dismantling the old building (structure) and performing surface roughening treatment.

[0017] Furthermore, the compressive strength of the new concrete is not lower than the compressive strength of the old concrete in the recycled component.

[0018] Furthermore, the first connecting piece buckles the column longitudinal reinforcement from the outside, and the first connecting piece is welded to the old stirrups.

[0019] Furthermore, the yield strength of the steel bars of the first connecting member is not lower than the yield strength of the old stirrups.

[0020] Furthermore, the second connecting piece is welded to the old longitudinal reinforcement and the column longitudinal reinforcement respectively.

[0021] Furthermore, the yield strength of the steel bars of the second connecting member is not lower than the smaller value of the yield strength of the old longitudinal bars and the yield strength of the column longitudinal bars.

[0022] The construction method of the precast concrete column with built-in recycled components comprises the following steps:

[0023] (1) Processing and manufacturing column longitudinal reinforcement, spiral stirrups, ordinary or composite stirrups, first connectors and second connectors;

[0024] (2) removing the protective layer of the stirrups of the old concrete component and roughening the surface to obtain a regenerated component, and locally treating the portion of the regenerated component where the second connecting piece is to be provided so that the welding surface of the old longitudinal reinforcement at the portion is exposed;

[0025] (3) Arrange column longitudinal reinforcement and grouting sleeves, tie spiral stirrups to column longitudinal reinforcement, and tie ordinary or composite stirrups to grouting sleeves to form a steel cage;

[0026] (4) adjusting the steel cage prepared in step (3) to an upright state, and hanging the regenerated component from top to bottom into the steel cage;

[0027] (5) The first connecting piece is buckled to the column longitudinal reinforcement from the outside, the first connecting piece is welded to the adjacent old stirrups, and the second connecting piece is welded to the adjacent column longitudinal reinforcement and the old longitudinal reinforcement;

[0028] (6) Complete the formwork and horizontal formwork of the precast concrete column with built-in recycled components, hoist the steel cage and recycled components constructed in steps (4) and (5) into the cavity surrounded by the formwork in a horizontal manner, and complete the detailed positioning;

[0029] (7) Pour sufficient new concrete into the cavity enclosed by the formwork, vibrate it thoroughly and then maintain the concrete.

[0030] Compared with the prior art, the present invention has the following advantages and effects:

[0031] (1) The present invention directly utilizes old beam-type components or old column-type components instead of crushing them into recycled blocks or recycled aggregates for reuse, which greatly simplifies the processing procedures, significantly improves the recycling rate of old concrete, significantly reduces the amount of new concrete and the corresponding fresh cement, and has an outstanding carbon emission reduction effect.

[0032] (2) The present invention sets a first connecting piece to connect the old stirrups in the recycled component with the column longitudinal reinforcement in the precast concrete column, so that the old stirrups can play an additional lateral restraining effect on the column longitudinal reinforcement, ingeniously exerting the unique restraining effect of the old stirrups in the precast concrete column, and further appropriately reducing the amount of spiral stirrups in the precast concrete column, which has obvious economic benefits.

[0033] (3) The present invention arranges a second connecting piece to connect the old longitudinal reinforcement in the recycled component with the column longitudinal reinforcement in the precast concrete column, so that the old longitudinal reinforcement and the column longitudinal reinforcement are subjected to force synergistically, which can exert the longitudinal tensile effect of the old longitudinal reinforcement under earthquake action or large eccentricity to a certain extent, thereby appropriately reducing the amount of column longitudinal reinforcement in the precast concrete column, and has obvious economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the overall structure of a precast concrete column with a built-in regeneration component provided by an embodiment of the present invention;

[0035] Figure 2 is a partial structural schematic diagram of a regeneration component in a precast concrete column with a built-in regeneration component in an embodiment of the present invention;

[0036] Figure 3 Schematic diagram of the positional relationship between the recycled component, column longitudinal reinforcement and spiral stirrups in the precast concrete column with built-in recycled component in an embodiment of the present invention;

[0037] Figure 4 It is a schematic diagram of the specific structure of the first connecting member and the second connecting member in the precast concrete column with built-in regeneration components in an embodiment of the present invention;

[0038] Figure 5 It is a schematic diagram of the partial connection position of the first connecting member and the second connecting member in the precast concrete column with built-in regeneration component in an embodiment of the present invention;

[0039] In the figure: 1-recycled component; 2-column longitudinal reinforcement; 3-spiral stirrups; 4-ordinary or composite stirrups; 5-first connecting piece; 6-second connecting piece; 7-new concrete; 8-grouting sleeve; 9-old stirrups; 10-old longitudinal reinforcement; 11-old concrete. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below in conjunction with the embodiments and drawings, but the embodiments of the present invention are not limited thereto. It should be pointed out that if there are any processes that are not particularly described in detail below, they can be implemented by those skilled in the art with reference to the prior art.

[0041] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5As shown, the present invention provides a precast concrete column with built-in recycled components, including recycled components 1, column longitudinal reinforcement 2, spiral stirrups 3, ordinary or composite stirrups 4, a first connecting member 5, a second connecting member 6, new concrete 7 and a grouting sleeve 8.

[0042] The recycled component 1 includes old stirrups 9, old longitudinal reinforcements 10 and old concrete 11, the old longitudinal reinforcements 10 are located in the old concrete 11, the old stirrups 9 are located on the outside of the old longitudinal reinforcements 10, and the outermost side of the old stirrups 9 is basically flush with the outer surface of the old concrete 11; the height and cross-sectional width of the recycled component 1 are respectively smaller than the height and cross-sectional width of the precast concrete column; the volume of the recycled component 1 is not less than 40% of the volume of the precast concrete column.

[0043] A grouting sleeve 8 is arranged below the regeneration component 1, and a distance is left between the two. The net distance between the lower surface of the regeneration component 1 and the grouting sleeve 8 is 50-100 mm. The setting range of the common or composite stirrups 4 is the area where the grouting sleeve 8 is located; the setting range of the spiral stirrups 3 is the area where the grouting sleeve 8 is not located.

[0044] The grouting sleeve 8 is a connecting piece used to connect the prefabricated column with the frame node or column at its lower end. The longitudinal reinforcement of the frame node or column at its lower end will be inserted into the grouting sleeve during construction, and then grouting material will be poured into the sleeve to achieve the purpose of connection.

[0045] The regenerated component 1 is surrounded by the new concrete 7, and the column longitudinal reinforcement 2 is longitudinally arranged in the new concrete 7. The first connecting piece 5 is made of steel bars and used to connect the old stirrups 9 and the column longitudinal reinforcement 2; the setting range of the first connecting piece 5 is the area where the regenerated component 1 is located; specifically, the first connecting piece 5 buckles the column longitudinal reinforcement 2 from the outside, and the first connecting piece 5 is welded to the old stirrups 9. The second connecting piece 6 is made of steel bars and used to connect the old longitudinal reinforcement 10 and the column longitudinal reinforcement 2; the setting range of the second connecting piece 6 is the upper longitudinal range of 0-500mm and the lower longitudinal range of 0-500mm in the area where the regenerated component 1 is located. When considering the earthquake effect or large bias pressure, the bending moment of the regenerated component 1 within the upper and lower ends is the largest. Therefore, the second connecting piece 6 is arranged within a certain range at both ends to allow the old longitudinal reinforcement 10 and the column longitudinal reinforcement 2 to cooperate in force, thereby exerting the longitudinal tensile effect of the old longitudinal reinforcement 10; specifically, the second connecting piece 6 is welded to the old longitudinal reinforcement 10 and the column longitudinal reinforcement 2 respectively.

[0046] The new concrete 7 is natural aggregate concrete or recycled aggregate concrete with a maximum particle size of coarse aggregate not exceeding 20 mm, or recycled aggregate concrete containing recycled sand from construction waste; except for the interior of the grouting sleeve 8, new concrete 7 is poured on the top, bottom and around the recycled component 1, and new concrete is also poured around the grouting sleeve 8.

[0047] In some embodiments of the present invention, the recycled component 1 is obtained by removing the stirrup protection layer from the old concrete component obtained by dismantling the old building (structure) and performing surface roughening treatment.

[0048] In some embodiments of the present invention, the height of the precast concrete column is 3000 mm, the cross-sectional width is 600 mm, and the thickness of the stirrup protection layer is 25 mm.

[0049] In some embodiments of the present invention, the compressive strength of the new concrete 7 is 60 MPa, and the compressive strength of the old concrete 11 of the recycled structure 1 is 50 MPa.

[0050] In some embodiments of the present invention, the column longitudinal reinforcement 2 adopts HRB400 hot-rolled steel bars with a diameter of 20 mm; the spiral stirrups 3 adopt HRB400 hot-rolled steel bars with a diameter of 10 mm; the ordinary or composite stirrups 4 adopt HRB400 hot-rolled steel bars with a diameter of 10 mm; the old stirrups 9 adopt HRB400 hot-rolled steel bars with a diameter of 10 mm; and the old longitudinal reinforcement 10 adopts HRB400 hot-rolled steel bars with a diameter of 20 mm.

[0051] In some embodiments of the present invention, the first connecting member 5 and the second connecting member 6 are both made of HRB400 hot-rolled steel bars with a diameter of 6 mm.

[0052] The above-mentioned construction method of a precast concrete column with built-in recycled components comprises the following steps:

[0053] (1) Processing and manufacturing column longitudinal reinforcement 2, spiral stirrups 3, ordinary or composite stirrups 4, first connecting pieces 5 and second connecting pieces 6;

[0054] (2) removing the protective layer of the stirrups of the old concrete component and roughening the surface to obtain the regenerated component 1, and locally treating the portion of the regenerated component 1 where the second connecting member 6 is to be provided, so that the welding surface of the old longitudinal reinforcement 10 at the portion is exposed;

[0055] (3) Arrange the column longitudinal reinforcement 2 and the grouting sleeve 8, tie the spiral stirrups 3 to the column longitudinal reinforcement 2, and tie the ordinary or composite stirrups 4 to the grouting sleeve 8 to form a steel cage;

[0056] (4) adjusting the steel cage prepared in step (3) to an upright state, and hanging the regeneration component 1 from top to bottom into the steel cage;

[0057] (5) The first connecting piece 5 is buckled onto the column longitudinal reinforcement 2 from the outside, the first connecting piece 5 is welded to the adjacent old stirrups 9, and the second connecting piece 6 is welded to the adjacent column longitudinal reinforcement 2 and the old longitudinal reinforcement 10;

[0058] (6) Complete the formwork and horizontal formwork of the precast concrete column with built-in recycled components, hoist the steel cage and recycled components 1 constructed in steps (4) and (5) into the cavity surrounded by the formwork in a horizontal manner, and complete the detailed positioning;

[0059] (7) Pour sufficient new concrete 7 into the cavity enclosed by the formwork, vibrate it thoroughly and then cure it.

[0060] As a traditional practice, the old concrete components are often first crushed to remove the internal steel bars, and then the large blocks of concrete are directly used as recycled blocks, or the large blocks of concrete are further crushed multiple times to be refined into recycled aggregates for use. Whether it is to prepare recycled block concrete using recycled blocks or to prepare recycled aggregate concrete using recycled aggregates, a large amount of fresh cement and other cementitious materials are required. Cement production not only consumes a lot of energy, but also has huge carbon emissions. In the process of multiple crushing, a large amount of powder that is difficult to use will inevitably be produced, which significantly reduces the recycling rate of old concrete. On the other hand, the old steel bars taken out in the process of crushing old concrete components also need to go through complex processes such as smelting before they can be reused as resources. These complex processes also consume a lot of energy and emit a lot of CO2, and the carbon emission reduction effect is not obvious.

[0061] In order to solve the above problems, the present invention proposes for the first time the idea of ​​directly recycling old beam-type components and old column-type components at the component level, instead of crushing the concrete therein into recycled blocks or recycled aggregates. This not only greatly simplifies the processing procedures, but also avoids a large amount of powder output. More importantly, it can significantly reduce the amount of new concrete and the corresponding fresh cement, and the energy-saving and carbon-reducing effects are significant. At the same time, since the steel bars inside the old concrete components can also provide important assistance in the service process of the new components, it not only avoids the cumbersome removal process of the old steel bars and the subsequent smelting and other complex processes, as well as the corresponding energy consumption and CO2 emissions, but also reduces the reinforcement requirements of the new components to a certain extent, which undoubtedly makes the present invention have greater advantages. Prior to this, there have been no related reports in the world on the direct recycling of old beam-type components and old column-type components in new components.

[0062] According to the present invention, although the steel bars inside the old concrete components are no longer taken out and sold, which seems to reduce a certain amount of economic income, which is also the main reason why predecessors found it difficult to think of directly recycling old beam components and old column components, the equipment and labor costs related to the crushing of old concrete components and the removal of steel bars can be saved, the expenses for the transportation and dumping of a large amount of powder can be avoided, the steel bars inside the old concrete components play a certain load-bearing role, which reduces the reinforcement demand of the new components, and the new concrete brought about by the direct recycling of old concrete components in new components and the corresponding fresh cement consumption are significantly reduced, resulting in cost savings, all of which make the present invention have good comprehensive economic benefits.

[0063] In summary, the present invention has good benefits in social, economic and ecological aspects.

[0064] According to the method of the present invention, a series of embodiments can also be developed, which does not limit the present invention in any form. Therefore, any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. Prefabricated concrete columns with built-in recycled components, characterized in that: It comprises a recycled component (1), a column longitudinal reinforcement (2), a spiral stirrup (3), a common or composite stirrup (4), a first connecting piece (5), a second connecting piece (6), new concrete (7) and a grouting sleeve (8); The recycled component (1) is surrounded by new concrete (7), the recycled component (1) comprises old stirrups (9), old longitudinal bars (10) and old concrete (11), the height and cross-sectional width of the recycled component (1) are respectively smaller than the height and cross-sectional width of the precast concrete column, and the volume of the recycled component (1) is not less than 40% of the volume of the precast concrete column; the recycled component (1) is obtained by removing the stirrup protective layer from the old concrete component dismantled from the old building (structure) and performing surface roughening treatment; The column longitudinal reinforcement (2) is located in the new concrete (7); The grouting sleeve (8) is located below the regeneration component (1). The grouting sleeve (8) is a connecting piece used to connect the prefabricated column and the frame node or column at the lower end thereof. The longitudinal reinforcement of the frame node or column at the lower end thereof is inserted into the grouting sleeve during construction, and then grouting material is poured into the sleeve to achieve the purpose of connection. The arrangement range of the common or composite stirrups (4) is the area where the grouting sleeve (8) is located; The setting range of the spiral stirrup (3) is the area where the non-grouting sleeve (8) is located; The first connecting member (5) is made of steel bars and is used to connect the old stirrups (9) and the column longitudinal bars (2). The shape of the first connecting member (5) is The first connecting member (5) is arranged in the area where the regenerated component (1) is located, the steel bar yield strength of the first connecting member (5) is not less than the yield strength of the old stirrups (9), the first connecting member (5) buckles the column longitudinal reinforcement (2) from the outside, and the first connecting member (5) is welded to the old stirrups (9); The second connecting member (6) is made of steel bars and is used to connect the old longitudinal bars (10) and the column longitudinal bars (2) so that the old longitudinal bars and the column longitudinal bars can be subjected to force in coordination and the longitudinal tensile effect of the old longitudinal bars can be exerted. The shape of the second connecting member (6) is The second connecting member (6) is arranged within the upper longitudinal range of 0-500 mm and the lower longitudinal range of 0-500 mm within the area where the regenerated component (1) is located. The steel yield strength of the second connecting member (6) is not less than the smaller value of the yield strength of the old longitudinal reinforcement (10) and the yield strength of the column longitudinal reinforcement (2). The second connecting member (6) is welded to the old longitudinal reinforcement (10) and the column longitudinal reinforcement (2) respectively. New concrete (7) is poured around the grouting sleeve (8) and the top, bottom and surrounding of the recycled component (1) except for the inside of the grouting sleeve (8). The new concrete (7) is natural aggregate concrete or recycled aggregate concrete with a maximum particle size of coarse aggregate not greater than 20 mm, or recycled aggregate concrete containing recycled sand from construction waste soil; The construction steps of the prefabricated concrete column with built-in recycled components include: (1) Processing and manufacturing column longitudinal reinforcement (2), spiral stirrups (3), ordinary or composite stirrups (4), first connecting pieces (5) and second connecting pieces (6); (2) removing the protective layer of the stirrups of the old concrete component and performing surface roughening treatment to obtain a regenerated component (1), and locally treating the portion of the regenerated component (1) where the second connecting member (6) is to be provided, so that the welding surface of the old longitudinal reinforcement (10) at the portion is exposed; (3) arranging the column longitudinal reinforcement (2) and the grouting sleeve (8), tying the spiral stirrups (3) to the column longitudinal reinforcement (2), and tying the ordinary or composite stirrups (4) to the grouting sleeve (8) to form a steel cage; (4) adjusting the steel cage prepared in step (3) to an upright state, and hanging the regenerated component (1) from top to bottom into the steel cage; (5) The first connecting piece (5) is buckled onto the column longitudinal reinforcement (2) from the outside, the first connecting piece (5) is welded to the adjacent old stirrups (9), and the second connecting piece (6) is welded to the adjacent column longitudinal reinforcement (2) and the old longitudinal reinforcement (10); (6) Complete the formwork and horizontal formwork of the precast concrete column with built-in recycled components, hoist the steel cage and recycled components (1) constructed in steps (4) and (5) into the cavity surrounded by the formwork in a horizontal manner, and complete the detailed positioning; (7) Pour new concrete (7) into the cavity enclosed by the formwork, vibrate it thoroughly and then cure it.

2. The prefabricated concrete column with built-in recycled components according to claim 1, characterized in that: The net distance between the lower surface of the regeneration component (1) and the grouting sleeve (8) is 50-100 mm.

3. The prefabricated concrete column with built-in recycled components according to claim 1, characterized in that: The cross-sectional width of the recycled component (1) is at least 150 mm smaller than the cross-sectional width of the precast concrete column.

4. The prefabricated concrete column with built-in recycled components according to claim 1, characterized in that: The compressive strength of the new concrete (7) is not lower than the compressive strength of the old concrete (11) in the recycled component (1).

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