REINFORCED RECYCLED LUMP/AGGREGATE CONCRETE PRECAST COLUMN AND CONSTRUCTION METHOD THEREOF

Abstract

A reinforced recycled block/aggregate concrete precast column and a construction method are provided. The reinforced recycled block/aggregate concrete precast column includes several first one-bar hoops, vertical reinforcement bars, several second one-bar hoops, a flexible hinge area, and recycled block/aggregate concrete; the first one-bar hoops and second one-bar hoops are each provided with an anchor end; the first one-bar hoops and second one-bar hoops are disposed in the flexible hinge area, and only the second one-bar hoops are disposed outside the flexible hinge area; the outer edge of each first one-bar hoop is flush with the outer surface of the reinforced recycled block/aggregate concrete precast column; and the interior of the reinforced recycled block/aggregate concrete precast column is filled with the recycled block/aggregate concrete, thereby greatly increasing the recycling rate of engineering waste, reducing shedding of a concrete protective layer in the flexible hinge area of the column.

Claims

1. A reinforced recycled lump/aggregate concrete precast column, comprising a plurality of first one-bar confinements, longitudinal bars, a plurality of second one-bar confinements, a plastic hinge region, and recycled lump/aggregate concrete; each of the first one-bar confinements and each of the second one-bar confinements being provided with an anchoring end; the plurality of first one-bar confinements and some of the plurality of second one-bar confinements being arranged in the plastic hinge region, and only some of the second one-bar confinements being arranged outside the plastic hinge region; outer edges of the first one-bar confinements being flush with outer surfaces of the reinforced recycled lump/aggregate concrete precast column, the first one-bar confinements being configured to restrain a concrete cover, and a vertical spacing between two adjacent first one-bar confinements of the first one-bar confinements being not greater than 200 mm; the second one-bar confinements abutting against the longitudinal bars, and the second one-bar confinements being configured to restrain the longitudinal bars; the anchoring end being formed by bending at 135° twice; and an interior of the reinforced recycled lump/aggregate concrete precast column being filled with the recycled lump/aggregate concrete, the recycled lump/aggregate concrete consisting of fresh concrete and demolished concrete lumps, and the fresh concrete being recycled aggregate concrete containing recycled coarse aggregates and excavated soil.

2. The reinforced recycled lump/aggregate concrete precast column according to claim 1, wherein a mass ratio of the recycled coarse aggregates to natural coarse aggregates in the fresh concrete is not greater than 4, the excavated soil partially or completely replaces natural sand, and a mass ratio of the excavated soil to the natural sand is not less than 1.

3. The reinforced recycled lump/aggregate concrete precast column according to claim 2, wherein a strength grade of the fresh concrete is not lower than C40; and the demolished concrete lumps are lumps formed by breaking old buildings, structures, and roads after removing all or part of steel bars, and a characteristic size of each of the demolished concrete lumps is not less than 60 mm.

4. The reinforced recycled lump/aggregate concrete precast column according to claim 3, wherein a mass ratio of the demolished concrete lumps to the fresh concrete in the recycled lump/aggregate concrete is 1:4 to 2:3.

5. The reinforced recycled lump/aggregate concrete precast column according to claim 4, wherein each of the first one-bar confinements and each of the second one-bar confinements is a stirrup formed by bending a high-strength steel bar for multiple times, and a size of the outer edge of each of the first one-bar confinements is larger than the size of an outer edge of each of the second one-bar confinements.

6. The reinforced recycled lump/aggregate concrete precast column according to claim 5, wherein a length of each of two straight segments of the anchoring end is not less than a larger value in 10 d and 75 mm, and d is a diameter of the stirrup.

7. The reinforced recycled lump/aggregate concrete precast column according to claim 6, wherein a height of the plastic hinge region is between 1.0 h and 2.0 h, and h is a cross-sectional height of the reinforced recycled lump/aggregate concrete precast column.

8. The reinforced recycled lump/aggregate concrete precast column according to claim 7, wherein a spacing between the two adjacent second one-bar confinements in the plastic hinge region is not greater than a smaller value in 6 D and 100 mm, and D is a minimum diameter of the longitudinal bars; and a spacing between the two adjacent second one-bar confinements outside the plastic hinge region is not greater than 10 D.

9. The reinforced recycled lump/aggregate concrete precast column according to claim 1, wherein a yield strength of each of the first one-bar confinements and the second one-bar confinements is not less than 500 MPa.

10. A construction method for the reinforced recycled lump/aggregate concrete precast column according to claim 9, comprising: processing and making the plurality of first one-bar confinements, the longitudinal bars, and the plurality of second one-bar confinements; arranging the longitudinal bars, positioning a vertical position of each of the first one-bar confinements and the second one-bar confinements, and simultaneously positioning a relative horizontal position between each of the first one-bar confinements and each of the longitudinal bars; arranging the first one-bar confinements and the second one-bar confinements in the plastic hinge region in sequence, and simultaneously completing arranging of the second one-bar confinements in a remaining region; completing formwork making and horizontal installation of the reinforced recycled lump/aggregate concrete precast column, at this time the outer edge of each of the first one-bar confinements being in contact with an inner surface of a formwork; and fully wetting the demolished concrete lumps in advance, and casting the reinforced recycled lump/aggregate concrete precast column by means of horizontal construction; and during casting, first putting the demolished concrete lumps into the formwork at a time, then pouring the fresh concrete into the formwork and fully vibrating until the casting is completed.

11. The reinforced recycled lump/aggregate concrete precast column according to claim 2, wherein a yield strength of each of the first one-bar confinements and the second one-bar confinements is not less than 500 MPa.

12. A construction method for the reinforced recycled lump/aggregate concrete precast column according to claim 11, comprising: processing and making the plurality of first one-bar confinements, the longitudinal bars, and the plurality of second one-bar confinements; arranging the longitudinal bars, positioning a vertical position of each of the first one-bar confinements and the second one-bar confinements, and simultaneously positioning a relative horizontal position between each of the first one-bar confinements and each of the longitudinal bars; arranging the first one-bar confinements and the second one-bar confinements in the plastic hinge region in sequence, and simultaneously completing arranging of the second one-bar confinements in a remaining region; completing formwork making and horizontal installation of the reinforced recycled lump/aggregate concrete precast column, at this time the outer edge of each of the first one-bar confinements being in contact with an inner surface of a formwork; and fully wetting the demolished concrete lumps in advance, and casting the reinforced recycled lump/aggregate concrete precast column by means of horizontal construction; and during casting, first putting the demolished concrete lumps into the formwork at a time, then pouring the fresh concrete into the formwork and fully vibrating until the casting is completed.

13. The reinforced recycled lump/aggregate concrete precast column according to claim 3, wherein a yield strength of each of the first one-bar confinements and the second one-bar confinements is not less than 500 MPa.

14. A construction method for the reinforced recycled lump/aggregate concrete precast column according to claim 13, comprising: processing and making the plurality of first one-bar confinements, the longitudinal bars, and the plurality of second one-bar confinements; arranging the longitudinal bars, positioning a vertical position of each of the first one-bar confinements and the second one-bar confinements, and simultaneously positioning a relative horizontal position between each of the first one-bar confinements and each of the longitudinal bars; arranging the first one-bar confinements and the second one-bar confinements in the plastic hinge region in sequence, and simultaneously completing arranging of the second one-bar confinements in a remaining region; completing formwork making and horizontal installation of the reinforced recycled lump/aggregate concrete precast column, at this time the outer edge of each of the first one-bar confinements being in contact with an inner surface of a formwork; and fully wetting the demolished concrete lumps in advance, and casting the reinforced recycled lump/aggregate concrete precast column by means of horizontal construction; and during casting, first putting the demolished concrete lumps into the formwork at a time, then pouring the fresh concrete into the formwork and fully vibrating until the casting is completed.

15. The reinforced recycled lump/aggregate concrete precast column according to claim 4, wherein a yield strength of each of the first one-bar confinements and the second one-bar confinements is not less than 500 MPa.

16. A construction method for the reinforced recycled lump/aggregate concrete precast column according to claim 15, comprising: processing and making the plurality of first one-bar confinements, the longitudinal bars, and the plurality of second one-bar confinements; arranging the longitudinal bars, positioning a vertical position of each of the first one-bar confinements and the second one-bar confinements, and simultaneously positioning a relative horizontal position between each of the first one-bar confinements and each of the longitudinal bars; arranging the first one-bar confinements and the second one-bar confinements in the plastic hinge region in sequence, and simultaneously completing arranging of the second one-bar confinements in a remaining region; completing formwork making and horizontal installation of the reinforced recycled lump/aggregate concrete precast column, at this time the outer edge of each of the first one-bar confinements being in contact with an inner surface of a formwork; and fully wetting the demolished concrete lumps in advance, and casting the reinforced recycled lump/aggregate concrete precast column by means of horizontal construction; and during casting, first putting the demolished concrete lumps into the formwork at a time, then pouring the fresh concrete into the formwork and fully vibrating until the casting is completed.

17. The reinforced recycled lump/aggregate concrete precast column according to claim 5, wherein a yield strength of each of the first one-bar confinements and the second one-bar confinements is not less than 500 MPa.

18. A construction method for the reinforced recycled lump/aggregate concrete precast column according to claim 17, comprising: processing and making the plurality of first one-bar confinements, the longitudinal bars, and the plurality of second one-bar confinements; arranging the longitudinal bars, positioning a vertical position of each of the first one-bar confinements and the second one-bar confinements, and simultaneously positioning a relative horizontal position between each of the first one-bar confinements and each of the longitudinal bars; arranging the first one-bar confinements and the second one-bar confinements in the plastic hinge region in sequence, and simultaneously completing arranging of the second one-bar confinements in a remaining region; completing formwork making and horizontal installation of the reinforced recycled lump/aggregate concrete precast column, at this time the outer edge of each of the first one-bar confinements being in contact with an inner surface of a formwork; and fully wetting the demolished concrete lumps in advance, and casting the reinforced recycled lump/aggregate concrete precast column by means of horizontal construction; and during casting, first putting the demolished concrete lumps into the formwork at a time, then pouring the fresh concrete into the formwork and fully vibrating until the casting is completed.

19. The reinforced recycled lump/aggregate concrete precast column according to claim 6, wherein a yield strength of each of the first one-bar confinements and the second one-bar confinements is not less than 500 MPa.

20. A construction method for the reinforced recycled lump/aggregate concrete precast column according to claim 19, comprising: processing and making the plurality of first one-bar confinements, the longitudinal bars, and the plurality of second one-bar confinements; arranging the longitudinal bars, positioning a vertical position of each of the first one-bar confinements and the second one-bar confinements, and simultaneously positioning a relative horizontal position between each of the first one-bar confinements and each of the longitudinal bars; arranging the first one-bar confinements and the second one-bar confinements in the plastic hinge region in sequence, and simultaneously completing arranging of the second one-bar confinements in a remaining region; completing formwork making and horizontal installation of the reinforced recycled lump/aggregate concrete precast column, at this time the outer edge of each of the first one-bar confinements being in contact with an inner surface of a formwork; and fully wetting the demolished concrete lumps in advance, and casting the reinforced recycled lump/aggregate concrete precast column by means of horizontal construction; and during casting, first putting the demolished concrete lumps into the formwork at a time, then pouring the fresh concrete into the formwork and fully vibrating until the casting is completed.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0032] FIG. 1 is a schematic structural diagram of a reinforced recycled lump/aggregate concrete precast column;

[0033] FIG. 2 is a schematic diagram of a positional relationship between first one-bar confinements and longitudinal bars in the present embodiment;

[0034] FIG. 3 is a schematic diagram of a positional relationship between second one-bar confinements and longitudinal bars in the present embodiment; and

[0035] FIG. 4 is a schematic structural diagram of the first one-bar confinements and the second one-bar confinements as well as the corresponding anchoring ends in the present embodiment.

[0036] In which: 1: first one-bar confinement; 2: longitudinal bar; 3: second one-bar confinement; 4: plastic hinge region; 5: anchoring end; 6: fresh concrete; and 7:

[0037] demolished concrete lump.

DESCRIPTION OF EMBODIMENTS

[0038] The present invention is further described in detail below in conjunction with the embodiments and the accompanying drawings, but the implementations of the present invention are not limited thereto. It should be noted that if there are processes not particularly described in detail below, they may be implemented by those skilled in the art with reference to the prior art.

[0039] A reinforced recycled lump/aggregate concrete precast column in the present embodiment includes a plurality of first one-bar confinements 1, longitudinal bars 2, a plurality of second one-bar confinements 3, a plastic hinge region 4, and recycled lump/aggregate concrete, as shown in FIG. 1 (in order to clearly show specific arrangement of longitudinal bars and stirrups inside the column, part of fresh concrete of the column is hidden);

[0040] each of the first one-bar confinements 1 and the second one-bar confinements 3 is provided with an anchoring end 5;

[0041] the first one-bar confinements 1 and the second one-bar confinements 3 are alternately arranged in the plastic hinge region 4, and a spacing between the adjacent first one-bar confinement 1 and second one-bar confinement 3 is 50 mm; only the second one-bar confinements 3 are arranged in a region outside the plastic hinge region 4, and a spacing between the two adjacent second one-bar confinements 3 is 200 mm; outer edges of the first one-bar confinements 1 are flush with outer surfaces of the reinforced recycled lump/aggregate concrete precast column, and the first one-bar confinements 1 are configured to restrain a concrete cover, as shown in FIG. 2; the second one-bar confinements 3 abut against the longitudinal bars 2, and the second one-bar confinements 3 are configured to restrain the longitudinal bars 2, as shown in FIG. 3;

[0042] each of the first one-bar confinements 1 and the second one-bar confinements 3 is a stirrup formed by bending a high-strength steel bar for multiple times, and the anchoring end 5 is formed by twice bending at 135°, as shown in FIG. 4 (the first one-bar confinements and the second one-bar confinements have a same structure except different sizes);

[0043] an interior of the reinforced recycled lump/aggregate concrete precast column is filled with recycled lump/aggregate concrete;

[0044] the recycled lump/aggregate concrete is mainly formed by mixing fresh concrete 6 with demolished concrete lumps 7; a mass ratio of recycled coarse aggregates to natural coarse aggregates in the fresh concrete 6 is 1: 1, and fine aggregates (natural sand) are completely replaced with excavated soil; and a mass ratio of the demolished concrete lumps 7 to the fresh concrete 6 is 2: 3. Table 1 is a mix proportion of the fresh concrete 6 in the present embodiment, wherein cement is Shijing brand 42.5R ordinary Portland cement, the excavated soil is taken from Alluvial-Proluvial soil 5.5 m under the ground of a foundation pit in a supporting engineering project for underground comprehensive pipe gallery and road fast transformation of Guanghua first-class highway, and particles with a particle size larger than 4.75 mm should be screened out before use; the natural coarse aggregates with a particle size less than 26.5 mm are purchased from a factory near Guangzhou Nursery; the recycled coarse aggregates with a particle size less than 26.5 mm are obtained from crushing waste concrete at a Taicheng crushing yard in Baiyun District, Guangzhou; and a water reducer is a Sika 540P solid polycarboxylate water reducer. The actually measured slump of the fresh concrete 6 obtained according to the mix proportion in Table 1 is 195 mm, and the actually measured compressive strength can reach 41.4 MPa. According to this mix proportion and the mass ratio of the demolished concrete lumps 7 to the fresh concrete 6, it may be calculated that the construction and demolition wastes (including the excavated soil, the recycled coarse aggregates, and the demolished concrete lumps) accounts for 70% of the total mass of the concrete.

TABLE-US-00001 TABLE 1 Mix proportion of fresh concrete Fine Coarse aggregates aggregates (kg/m.sup.3) (kg/m.sup.3) Natural Recycled Water Water Cement Excavated coarse coarse (kg/m.sup.3) (kg/m.sup.3) (kg/m.sup.3) soil aggregates aggregates reducer 226 430 614 570 570 0.39

[0045] In this embodiment, a cross-sectional size of the reinforced recycled lump/aggregate concrete precast column is 400 mm×400 mm, and a height of the reinforced recycled lump/aggregate concrete precast column is 4,000 mm. A thickness of the concrete cover is 25 mm. A height of the plastic hinge region 4 is 800 mm.

[0046] In this embodiment, both the first one-bar confinements 1 and the second one-bar confinements 3 adopt HRB600 hot-rolled steel bars with a diameter of 8 mm; the longitudinal bars 2 adopt HRB400 hot-rolled steel bars with a diameter of 20 mm; a length of two straight segments of the anchoring end 5 is 80 mm; a strength grade of the fresh concrete 6 is C40; and a strength grade of the demolished concrete lumps 7 is C30, and a characteristic size of the demolished concrete lumps 7 is ranged from 60 to 100 mm.

[0047] A construction method for the reinforced recycled lump/aggregate concrete precast column includes the following steps: [0048] (1): processing and making a plurality of first one-bar confinements 1, longitudinal bars 2, and a plurality of second one-bar confinements 3; [0049] (2): arranging the longitudinal bars 2, positioning a vertical position of each of the first one-bar confinements 1 and the second one-bar confinements 3, and simultaneously positioning a relative horizontal position between each of the first one-bar confinements 1 and each of the longitudinal bars 2; [0050] (3): alternately arranging the first one-bar confinements 1 and the second one-bar confinements 3 in the plastic hinge region 4 in sequence, and simultaneously completing arranging of the second one-bar confinements 3 in the remaining region; [0051] (4): completing formwork making and horizontal installation of the reinforced recycled lump/aggregate concrete precast column, at this time an outer edge of each of the first one-bar confinements 1 being in contact with an inner surface of a formwork; and [0052] (5): fully wetting demolished concrete lumps 7 in advance, and casting the reinforced recycled lump/aggregate concrete precast column by means of horizontal construction; and during casting, first putting the demolished concrete lumps 7 into the formwork at a time, then pouring fresh concrete 6 into the formwork and fully vibrating until the casting is completed.

[0053] As described above, the present invention may be better implemented. The present invention significantly increases the total recycling ratio (may reach 70%, far higher than that of conventional recycled aggregate concrete (generally at most about 25%) and conventional recycled lump concrete (generally at most about 40%)) of the construction and demolition wastes in the concrete.

[0054] The implementations of the present invention are not limited by the above-mentioned embodiments, and any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present disclosure shall be equivalent substitution modes, which are included within the scope of protection of the present disclosure.