Prefabricated floor slabs and corrugated steel plate combined floor slabs directly using old slabs and construction methods

Abstract

The present invention discloses a prefabricated floor slab and a corrugated steel plate composite floor slab and a construction method that directly utilize old slabs. The prefabricated floor slab includes an old concrete slab, new concrete, a steel mesh at the bottom of the slab, a steel mesh on the surface of the slab, steel bars and an overhanging rack. The corrugated steel plate composite floor slab includes an old concrete slab, new concrete, a steel mesh on the surface of the slab, steel bars, corrugated steel plates, longitudinal force-bearing steel bars at the bottom of the slab and transverse distribution bars at the bottom of the slab. The present invention directly utilizes old concrete slabs 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 cement, and has an outstanding carbon emission reduction effect; vertical through holes are drilled on the old concrete slab, steel bars are inserted into the through holes, and the gap between the two is filled with high-strength grouting material to further enhance the shear resistance of the interface between the new and old concrete.

Description

Technical Field

[0001] The invention relates to the technical field of recycling waste concrete, and in particular to a prefabricated floor slab and a corrugated steel plate combined floor slab directly utilizing old concrete slabs and a construction method thereof. Background Art

[0002] With the rapid development of urban construction, the recycling and reuse of old concrete components has gradually attracted social attention. The current practice is to crush 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, the process of crushing old concrete components into recycled aggregates or recycled blocks is relatively cumbersome, and a large amount of difficult-to-use powder will be produced during the crushing process, which will significantly reduce the recycling rate of old concrete; at the same time, the preparation of recycled aggregate concrete will consume a lot of cement, and the proportion of new concrete in recycled block concrete is as high as 70%, and the production of these new concretes will also consume a lot of cement. Since cement production will produce a large amount of CO2 emissions, the carbon emission reduction effect of the above current practices needs to be further improved. For this reason, the recycling and reuse strategy of old concrete components needs to be further improved. If old concrete components can be directly used in the production of new components without crushing, it will undoubtedly greatly alleviate the above problems. 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. Floor slabs are important horizontal components in building structures. In the production process of precast floor slabs and corrugated steel plate composite floor slabs, if the old concrete slabs can be directly poured inside the new slabs, it is an effective way to realize the direct utilization of the old concrete slabs. Summary of the invention

[0004] At present, the existing technology cannot realize the component-level recycling and reuse of old concrete slabs. The present invention provides prefabricated floor slabs and corrugated steel plate composite floor slabs and their construction methods that directly utilize old concrete slabs. It is the first to propose an effective countermeasure for recycling and reusing old concrete slabs as a whole in prefabricated floor slabs and corrugated steel plate composite floor slabs, which has a significant carbon emission reduction effect.

[0005] In order to achieve the purpose of the present invention, the present invention provides a prefabricated floor slab that directly utilizes old concrete slabs, comprising old concrete slabs, new concrete, a slab bottom steel mesh, a slab surface steel mesh, steel bar inserts and an overhanging tooth bar; the length and width of the old concrete slab are respectively smaller than the length and width of the prefabricated floor slab, and the volume of the old concrete slab is not less than 50% of the volume of the prefabricated floor slab; the new concrete is natural aggregate concrete or recycled aggregate concrete or recycled aggregate concrete containing engineering slag recycled sand with a maximum particle size of coarse aggregate not greater than 20 mm; in the old concrete Through holes are drilled vertically along the upper edge of the earth slab, and steel bars are inserted into the through holes; the gaps between the through holes and the steel bars are filled with high-strength grouting material; the bottom steel mesh and the surface steel mesh are located below and above the old concrete slab respectively; the internal upper longitudinal steel bars of the old concrete slab are connected with the longitudinal steel bars of the surface steel mesh; the extended rack is located on the side wall of the precast slab, and steel components are inserted into the extended rack, and the steel components are extended into the main body of the precast slab in the reverse direction; new concrete is poured on the top, bottom and sides of the old concrete slab and inside the extended rack.

[0006] The present invention also provides a corrugated steel plate composite floor slab that directly utilizes old concrete slabs, comprising old concrete slabs, new concrete, a slab surface steel bar mesh, steel bar inserts, a corrugated steel plate, a slab bottom longitudinal force-bearing steel bar and a slab bottom transverse distribution bar; the length and width of the old concrete slab are respectively smaller than the length and width of the corrugated steel plate composite floor slab; 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 or recycled aggregate concrete containing engineering slag recycled sand; through holes are vertically drilled on the old concrete slab, steel bar inserts are inserted into the through holes, and the gaps between the through holes and the steel bar inserts are filled with high-strength grouting material; the slab surface steel bar mesh is located above the old concrete slab; the internal upper longitudinal steel bars of the old concrete slab are connected to the longitudinal steel bars of the slab surface steel bar mesh; the corrugated steel plate is located below the old concrete slab, and the slab bottom longitudinal force-bearing steel bar and the slab bottom transverse distribution bar are arranged on the corrugated steel plate; new concrete is poured on the upper, lower and surrounding areas of the old concrete slab.

[0007] Furthermore, for the prefabricated floor slabs that directly utilize old concrete slabs, the steel components extend reversely into the prefabricated floor slab body by no less than 50 mm, and the steel components are steel bars or angle steels or I-shaped steels with a yield strength of no less than 235 MPa.

[0008] Furthermore, the length and width of the old concrete slab are at least 80 mm smaller than the length and width of the prefabricated floor slab or the corrugated steel plate composite floor slab.

[0009] Furthermore, the upper and lower surfaces of the old concrete slab are each cut to a thickness of 5-20 mm and roughened.

[0010] Furthermore, the old concrete slab is a concrete slab produced by demolishing old buildings or structures.

[0011] Furthermore, the compressive strength of the new concrete is not lower than the concrete compressive strength of the old concrete slab.

[0012] Furthermore, the length of the steel bar insert is 10-30 mm greater than the original thickness of the old concrete slab and not greater than the thickness of the prefabricated floor slab or the corrugated steel plate composite floor slab.

[0013] The construction method of the prefabricated floor slab directly using the old concrete slab comprises the following steps:

[0014] (1) Tie the bottom steel mesh and the surface steel mesh, and place the bottom steel mesh above the bottom formwork; lay a protective layer pad between the bottom steel mesh and the bottom formwork;

[0015] (2) Drill vertical through holes on the old concrete slab, insert the steel bars into the through holes and fill the gap between them with high-strength grouting material;

[0016] (3) inserting a steel component into the extended rack, and the steel component extends into the main body of the prefabricated floor slab in the reverse direction;

[0017] (4) Pour a layer of new concrete into the casting mold. The height of this layer of new concrete exceeds the steel mesh at the bottom of the slab, and vibrate it to make it dense.

[0018] (5) placing the old concrete slab that has been fully moistened in advance directly on the layer of new concrete poured in step (4), and applying a vertical downward vibration pressure on the upper surface of the old concrete slab for a duration of not less than 2 minutes;

[0019] (6) A slab surface steel mesh is laid on top of the old concrete slab. The slab surface steel mesh is spot welded to the adjacent steel bar inserts. The upper longitudinal steel bars inside the old concrete slab are welded to the longitudinal steel bars of the slab surface steel mesh using pre-bent steel bars. Then, a sufficient amount of new concrete is poured into the casting mold, fully vibrated and cured.

[0020] The construction method of the corrugated steel plate composite floor slab directly using the old concrete slab comprises the following steps:

[0021] (1) Arrange the longitudinal stress-bearing steel bars and transverse distribution bars at the bottom of the corrugated steel plate;

[0022] (2) Drill through holes in the old concrete slab, insert the steel bars into the through holes and fill the gap between the two with high-strength grouting material;

[0023] (3) Pour a layer of new concrete into the casting mold. The height of this layer of new concrete exceeds the transverse distribution reinforcement at the bottom of the slab, and vibrate it to make it dense.

[0024] (4) placing the old concrete slab that has been fully moistened in advance directly on the layer of new concrete poured in step (3), and applying a vertical downward vibration pressure on the upper surface of the old concrete slab for a duration of not less than 2 minutes;

[0025] (5) A slab surface steel mesh is laid on top of the old concrete slab. The slab surface steel mesh is spot welded to the adjacent steel bar inserts. The upper longitudinal steel bars inside the old concrete slab are welded to the longitudinal steel bars of the slab surface steel mesh using pre-bent steel bars. Then, a sufficient amount of new concrete is poured into the casting mold, fully vibrated and cured.

[0026] Compared with the prior art, the present invention has the following advantages and effects:

[0027] (1) Directly utilizing old concrete slabs instead of crushing them into recycled blocks or recycled aggregates for reuse greatly simplifies the processing procedures, significantly improves the recycling rate of old concrete, and significantly reduces the amount of new concrete and the corresponding fresh cement, with a significant carbon emission reduction effect.

[0028] (2) An overhanging rack is provided at the end of the floor slab, and a steel component is arranged near the connection surface between the overhanging rack and the main body of the floor slab. During on-site assembly, the overhanging rack is placed on the upper surface of the prefabricated composite beam to bear the load during construction, thereby solving the problem that a large number of vertical supports need to be set up on the construction site, resulting in high costs and complex construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the overall structure of a prefabricated floor slab that directly utilizes old concrete slabs provided by an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of the overall structure of a corrugated steel plate composite floor slab that directly utilizes old concrete slabs provided by an embodiment of the present invention;

[0031] Figure 3 It is a partial structural schematic diagram of an old concrete slab in a prefabricated floor slab and a corrugated steel plate composite floor slab directly utilizing the old concrete slab in an embodiment of the present invention;

[0032] Figure 4 It is a partial structural schematic diagram of a steel component in a prefabricated floor slab directly utilizing old concrete slabs according to an embodiment of the present invention;

[0033] In the figure: 1- old concrete slab; 2- new concrete; 3- steel mesh at the bottom of the slab; 4- steel mesh at the surface of the slab; 5- steel bar insertions; 6- extended racks; 7- corrugated steel plate; 8- holes; 9- steel parts; 10- longitudinal stress-bearing steel bars at the bottom of the slab; 11- transverse distribution bars at the bottom of the slab. DETAILED DESCRIPTION

[0034] 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.

[0035] like Figure 1 , Figure 3 , Figure 4 As shown, the present invention provides a prefabricated floor slab that directly utilizes old concrete slabs, comprising an old concrete slab 1, new concrete 2, a slab bottom steel mesh 3, a slab surface steel mesh 4, steel bar inserts 5 and an overhanging rack 6; the length and width of the old concrete slab 1 are at least 80 mm smaller than the length and width of the prefabricated floor slab, respectively, and the volume of the old concrete slab 1 is not less than 50% of the volume of the prefabricated floor slab; the upper and lower surfaces of the old concrete slab 1 are each reduced by 5-20 mm in thickness and roughened to increase the roughness of the interface between the new and old concrete; the new concrete 2 is natural aggregate concrete or recycled aggregate concrete with a maximum coarse aggregate size of not more than 20 mm, or recycled aggregate concrete containing recycled sand from engineering slag; A through hole 8 is drilled vertically on the upper edge of the old concrete slab 1, and a steel bar 5 is inserted into the through hole 8; the gap between the through hole 8 and the steel bar 5 is filled with high-strength grouting material, and the steel bar 5 can further enhance the shear resistance of the interface between the new and old concrete; the bottom steel mesh 3 and the surface steel mesh 4 are respectively located below and above the old concrete slab 1; the internal upper longitudinal steel bars of the old concrete slab 1 are connected with the longitudinal steel bars of the surface steel mesh 4; the overhanging rack 6 is located on the side wall of the precast floor slab, and a steel component 9 is inserted into the overhanging rack 6, and the steel component 9 extends into the main body of the precast floor slab in the reverse direction by not less than 50 mm; new concrete 2 is poured on the upper, lower and surrounding areas of the old concrete slab 1 and inside the overhanging rack 6.

[0036] In some embodiments of the present invention, the prefabricated floor slab directly utilizing the old concrete slab has a width of 600 mm, a length of 3000 mm, a slab thickness of 150 mm, and a protective layer thickness of 15 mm.

[0037] In some embodiments of the present invention, the compressive strength of the new concrete 2 is 30 MPa, and the compressive strength of the old concrete slab 1 is 25 MPa.

[0038] In some embodiments of the present invention, the bottom steel mesh 3 and the surface steel mesh 4 are formed by binding steel bars along the span direction and along the width direction, and the reinforcement along the span direction is C10@200; the reinforcement along the width direction is C8@200.

[0039] The above-mentioned construction method of prefabricated floor slabs directly using old concrete slabs comprises the following steps:

[0040] (1) Tie the bottom steel mesh 3 and the surface steel mesh 4, and place the bottom steel mesh 3 above the bottom formwork; and lay a protective layer pad between the bottom steel mesh 3 and the bottom formwork;

[0041] (2) vertically drilling a through hole 8 on the old concrete slab 1, inserting the steel bar 5 into the through hole 8 and filling the gap between the two with high-strength grouting material;

[0042] (3) inserting a steel component 9 into the interior of the overhanging rack 6, and the steel component 9 extends in the reverse direction into the main body of the prefabricated floor;

[0043] (4) Pour a layer of new concrete 2 into the casting mold, the height of this layer of new concrete 2 exceeds the steel mesh 3 at the bottom of the slab, and vibrate and compact it;

[0044] (5) placing the old concrete slab 1 that has been fully moistened in advance directly on the layer of new concrete 2 poured in step (4), and applying a vertical downward vibration pressure for a duration of not less than 2 minutes to the upper surface of the old concrete slab 1;

[0045] (6) A slab surface steel mesh 4 is arranged above the old concrete slab 1, and the slab surface steel mesh 4 is locally spot welded to the adjacent steel bar insertion strips 5. The upper longitudinal steel bars inside the old concrete slab 1 are welded to the longitudinal steel bars of the slab surface steel mesh 4 using pre-bent steel bars, and then a sufficient amount of new concrete 2 is poured into the casting mold, which is fully vibrated and cured.

[0046] like Figure 2 As shown, a corrugated steel plate composite floor slab directly using old concrete slabs comprises an old concrete slab 1, new concrete 2, a slab surface steel mesh 4, steel bar inserts 5, a corrugated steel plate 7, a slab bottom longitudinal force-bearing steel bar 10 and a slab bottom transverse distribution bar 11; the length and width of the old concrete slab 1 are at least 80 mm smaller than the length and width of the corrugated steel plate composite floor slab respectively; the upper and lower surfaces of the old concrete slab 1 are respectively reduced by 5-20 mm in thickness and roughened to increase the roughness of the bonding surface between the new and old concrete; the new concrete 2 is natural aggregate concrete or recycled aggregate concrete with a maximum coarse aggregate size of not more than 20 mm or recycled concrete containing engineering slag Recycled aggregate concrete of sand; a through hole 8 is vertically provided on the old concrete slab 1, and a steel bar 5 is inserted into the through hole 8; the gap between the through hole 8 and the steel bar 5 is filled with high-strength grouting material, and the steel bar 5 can further improve the shear resistance of the interface between the new and old concrete; the slab surface steel mesh 4 is located above the old concrete slab 1; the internal upper longitudinal steel bars of the old concrete slab 1 are connected with the longitudinal steel bars of the slab surface steel mesh 4; the corrugated steel plate 7 is located below the old concrete slab 1, and the longitudinal force-bearing steel bars 10 at the bottom of the slab and the transverse distribution bars 11 at the bottom of the slab are arranged on the corrugated steel plate 7; new concrete 2 is poured on the top, bottom and around the old concrete slab 1.

[0047] In some embodiments of the present invention, the corrugated steel composite floor slab directly utilizing the old concrete slab has a width of 750 mm, a length of 3000 mm, and a slab thickness of 150 mm.

[0048] In some embodiments of the present invention, the compressive strength of the new concrete 2 is 30 MPa, and the compressive strength of the old concrete slab 1 is 25 MPa.

[0049] In some embodiments of the present invention, an open corrugated steel plate 7 is used, and the steel plate model is YX35-125-750. In some embodiments of the present invention, longitudinal force-bearing ribs 10 and transverse distribution ribs 11 are arranged at the bottom of the corrugated steel plate.

[0050] In some embodiments of the present invention, the plate surface steel mesh 4 is formed by tying steel bars along the span direction and along the width direction, with the reinforcement C10@200 along the span direction and the reinforcement C8@200 along the width direction.

[0051] The above-mentioned construction method of the corrugated steel plate composite floor slab directly using the old concrete slab comprises the following steps:

[0052] (1) Arrange the longitudinal stress-bearing steel bars 10 and the transverse distribution bars 11 on the bottom of the corrugated steel plate 7;

[0053] (2) drilling a through hole 8 on the old concrete slab 1, inserting the steel bar 5 into the through hole 8 and filling the gap between the two with high-strength grouting material;

[0054] (3) pouring a layer of new concrete 2 into the casting mold, the height of which exceeds the transverse distribution reinforcement 11 at the bottom of the slab, and vibrating and compacting it;

[0055] (4) placing the old concrete slab 1 that has been fully moistened in advance directly on the layer of new concrete 2 poured in step (3), and applying a vertical downward vibration pressure for a duration of not less than 2 minutes on the upper surface of the old concrete slab 1;

[0056] (5) A slab surface steel mesh 4 is arranged above the old concrete slab 1, and the slab surface steel mesh 4 is locally spot welded to the adjacent steel bar insertion strips 5. The upper longitudinal steel bars inside the old concrete slab 1 are welded to the longitudinal steel bars of the slab surface steel mesh 4 using pre-bent steel bars, and then a sufficient amount of new concrete 2 is poured into the casting mold, which is fully vibrated and cured.

[0057] As a traditional practice, the old concrete slabs are often first crushed, the internal steel bars are taken out and sold, and then the large blocks of concrete after crushing are directly used in the form of recycled blocks, or the large blocks of concrete are further crushed for 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, and cement production not only has high energy consumption, but also has huge carbon emissions. On the other hand, a large amount of powder that is difficult to use will inevitably be produced during the multiple crushing processes, thereby significantly reducing the recycling rate of the old concrete. In order to solve the above problems, the present invention proposes for the first time the idea of ​​directly recycling the old concrete slabs at the component level, instead of crushing them into recycled blocks or recycled aggregates. This not only greatly simplifies the processing process, but also avoids the output of powder. More importantly, it can significantly reduce the amount of new concrete and the corresponding fresh cement, and the energy-saving and carbon-reducing effect is significant. Prior to this, there have been no related reports on the direct recycling of old concrete slabs in new components in the world.

[0058] According to the present invention, the steel bars inside the old concrete slabs are no longer taken out and sold, which seems to reduce a certain amount of economic income. This is also the main reason why predecessors found it difficult to think of directly recycling the old concrete slabs. However, considering that the equipment and labor costs related to the crushing of the old concrete slabs and the removal of the steel bars can be saved, the expenses of transporting and dumping a large amount of powder can be avoided, and the cost savings caused by the new concrete brought about by the direct recycling of the old concrete slabs in the new components and the corresponding fresh cement consumption are significantly reduced, the present invention still has good overall comprehensive economic benefits. At the same time, the internal steel bars of the old concrete slabs can also provide a certain amount of assistance during the service of the new components, thereby reducing the reinforcement requirements of the new components, which undoubtedly makes the present invention have greater advantages.

[0059] 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 floor slabs directly using old concrete slabs, characterized in that: It comprises an old concrete slab (1), new concrete (2), a slab bottom steel mesh (3), a slab surface steel mesh (4), steel bar inserts (5) and an extended rack (6); The length and width of the old concrete slab (1) are respectively smaller than the length and width of the prefabricated floor slab, and the volume of the old concrete slab (1) is not less than 50% of the volume of the prefabricated floor slab; New concrete (2) refers to natural aggregate concrete or recycled aggregate concrete with a maximum coarse aggregate size of not more than 20 mm, or recycled aggregate concrete containing recycled sand from construction waste; A through hole (8) is drilled vertically on the old concrete slab (1), and a steel bar insert (5) is inserted into the through hole (8); a gap between the through hole (8) and the steel bar insert (5) is filled with a high-strength grouting material; The slab bottom steel mesh (3) and the slab surface steel mesh (4) are respectively located below and above the old concrete slab (1); the internal upper layer longitudinal steel bars of the old concrete slab (1) are connected to the longitudinal steel bars of the slab surface steel mesh (4); The overhanging rack (6) is located on the side wall of the prefabricated floor slab, a steel component (9) is inserted into the overhanging rack (6), and the steel component (9) extends into the main body of the prefabricated floor slab in the reverse direction; new concrete (2) is poured on the upper, lower and surrounding areas of the old concrete slab (1) and inside the overhanging rack (6); The steel component (9) extends into the prefabricated floor slab body in the reverse direction by not less than 50 mm, and the steel component (9) is a steel bar or angle steel or I-shaped steel with a yield strength of not less than 235 MPa; The length and width of the old concrete slab (1) are at least 80 mm smaller than the length and width of the prefabricated floor slab or the corrugated steel plate composite floor slab.

2. Directly utilize the corrugated steel plate composite floor of the old concrete slab, characterized in that: It comprises an old concrete slab (1), new concrete (2), a slab surface steel mesh (4), steel bar inserts (5), a corrugated steel plate (7), a slab bottom longitudinal force-bearing steel bar (10) and a slab bottom transverse distribution bar (11); The length and width of the old concrete slab (1) are respectively smaller than the length and width of the corrugated steel plate composite floor slab; New concrete (2) refers to natural aggregate concrete or recycled aggregate concrete with a maximum coarse aggregate size of not more than 20 mm, or recycled aggregate concrete containing recycled sand from construction waste; A through hole (8) is drilled vertically on the old concrete slab (1), a steel bar insert (5) is inserted into the through hole (8), and a gap between the through hole (8) and the steel bar insert (5) is filled with a high-strength grouting material; The slab surface steel mesh (4) is located above the old concrete slab (1); the internal upper layer longitudinal steel bars of the old concrete slab (1) are connected to the longitudinal steel bars of the slab surface steel mesh (4); The corrugated steel plate (7) is located below the old concrete plate (1), and bottom longitudinal stress-bearing steel bars (10) and bottom transverse distribution bars (11) are arranged on the corrugated steel plate (7); new concrete (2) is poured above, below and around the old concrete plate (1).

3. The floor slab according to any one of claims 1 to 2, characterized in that: The upper and lower surfaces of the old concrete slab (1) are cut to a thickness of 5-20 mm and roughened.

4. The floor slab according to any one of claims 1 to 2, characterized in that: The old concrete slab (1) is a concrete slab produced by demolishing old buildings or structures.

5. The floor slab according to any one of claims 1 to 2, characterized in that: The compressive strength of the new concrete (2) is not lower than the concrete compressive strength of the old concrete slab (1).

6. The floor slab according to any one of claims 1 to 2, characterized in that: The length of the steel bar insert (5) is greater than the original thickness of the old concrete slab (1) by 10-30 mm and is not greater than the thickness of the prefabricated floor slab or the corrugated steel plate composite floor slab.

7. A construction method for prefabricated floor slabs directly using old concrete slabs, characterized in that: The following steps are involved: (1) tying the slab bottom steel mesh (3) and the slab surface steel mesh (4), placing the slab bottom steel mesh (3) above the bottom formwork; and arranging a protective layer pad between the slab bottom steel mesh (3) and the bottom formwork; (2) drilling a through hole (8) vertically on the old concrete slab (1), inserting the steel bar (5) into the through hole (8) and filling the gap between the two with high-strength grouting material; (3) inserting a steel component (9) into the extended rack (6), and the steel component (9) extends in the reverse direction into the main body of the prefabricated floor slab; (4) pouring a layer of new concrete (2) into the casting mold, wherein the height of the new concrete (2) exceeds the steel mesh (3) at the bottom of the slab, and vibrating and compacting the concrete; (5) placing the old concrete slab (1) that has been fully moistened in advance directly on the layer of new concrete (2) poured in step (4), and applying a vertical downward vibration pressure for a preset time to the upper surface of the old concrete slab (1); (6) A slab surface steel mesh (4) is arranged above the old concrete slab (1), the slab surface steel mesh (4) and the adjacent steel bar inserts (5) are locally spot welded, and the upper longitudinal steel bars inside the old concrete slab (1) and the longitudinal steel bars of the slab surface steel mesh (4) are welded and connected using pre-bent steel bars, and then a sufficient amount of new concrete (2) is poured into the casting mold, fully vibrated and cured.

8. A construction method for directly utilizing corrugated steel plate composite floor slabs of old concrete slabs, characterized in that: The following steps are involved: (1) Arranging longitudinal stress-bearing steel bars (10) at the bottom of the plate and transverse distribution bars (11) at the bottom of the plate on the corrugated steel plate (7); (2) drilling a through hole (8) on the old concrete slab (1), inserting the steel bar (5) into the through hole (8) and filling the gap between the two with high-strength grouting material; (3) pouring a layer of new concrete (2) into the casting mold, wherein the height of the new concrete (2) exceeds the transverse distribution reinforcement (11) at the bottom of the slab, and vibrating and compacting the layer; (4) placing the old concrete slab (1) that has been fully moistened in advance directly on the layer of new concrete (2) poured in step (3), and applying a vibration pressure vertically downward for a preset time to the upper surface of the old concrete slab (1); (5) A slab surface steel mesh (4) is arranged above the old concrete slab (1), the slab surface steel mesh (4) and the adjacent steel bar inserts (5) are locally spot welded, and the upper internal longitudinal steel bars of the old concrete slab (1) and the longitudinal steel bars of the slab surface steel mesh (4) are welded and connected using pre-bent steel bars, and then a sufficient amount of new concrete (2) is poured into the casting mold, fully vibrated and cured.

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