High-ductility concrete laminated slab based on shape memory alloy

Abstract

The utility model belongs to the technical field of fabricated buildings, and discloses a high-ductility concrete laminated slab based on shape memory alloy, which comprises a high-ductility concrete bottom slab, a plurality of steel bar trusses and rib materials, the high-ductility concrete bottom plate is a flat plate with a preset thickness, and the plurality of steel bar trusses are arranged above the high-ductility concrete bottom plate in parallel; wherein the steel bar truss is arranged in the length direction of the high-ductility concrete bottom plate, and the bottom of the steel bar truss is embedded in the high-ductility concrete bottom plate; the rib materials are arranged in the high-ductility concrete bottom plate in the length direction and arranged between every two adjacent steel bar trusses. Wherein the rib material is a shape memory alloy; according to the high-ductility concrete laminated slab, the recovery stress of the shape memory alloy can be indirectly converted into the prestress in the high-ductility concrete laminated slab through the bonding effect between the shape memory alloy and the high-ductility concrete, and cracks generated in the production, transportation and construction processes of the laminated slab are effectively limited.

Description

Technical Field

[0001] The utility model belongs to the technical field of assembled buildings, and in particular relates to a high-ductility concrete composite plate based on shape memory alloy. Background Art

[0002] At present, the mainstream building structure in the construction industry is reinforced concrete structure, in which the steel bars are subjected to tension and the concrete is subjected to compression, forming a whole and serving as the main load-bearing component. After the traditional reinforced concrete structure is supported by formwork, the components are cast together through cast-in-place method, which makes the overall structure rigid and has good corrosion and fire resistance. However, it also has some defects, such as high labor costs, low productivity, and long construction period.

[0003] Compared with traditional cast-in-place buildings, prefabricated buildings are a new direction in construction. First, the components are mechanized in the factory, and then transported to the construction site for assembly and connection to form a whole. The emergence of prefabricated buildings is undoubtedly a new revolution in the construction field. While promoting the industrialization of construction, it is also conducive to the development of green buildings and the efficient use of resources, and effectively guarantees the physical quality of construction projects.

[0004] As an important component of prefabricated buildings, the traditional composite slab consists of two parts: an ordinary concrete base plate (thickness greater than 60mm) and a steel truss (providing rigidity during transportation and construction). In the factory, the lower half of the steel truss is buried in the ordinary concrete base plate and prefabricated according to the size requirements. After curing to the design strength, the prefabricated components are transported to the construction site for overall assembly and node connection. After that, a layer of concrete is poured on the upper part. After reaching the design strength, the cast-in-place concrete of the upper layer and the prefabricated components of the lower layer form a composite structure. The prefabricated part Produced in a factory, the production process is highly mechanized, low-cost, and high-precision, and it effectively avoids construction steps such as formwork. However, in the actual construction process, the weight of the prefabricated composite slabs is still relatively large, and lifting equipment is required to lift the prefabricated components at the construction site. Secondly, beard ribs need to be set around the composite slabs, which increases the difficulty of construction, reduces construction efficiency, and significantly increases costs. In addition, due to the low strength and ductility of ordinary concrete, cracks are easily generated during the production, transportation, and construction of the composite slabs, resulting in a low yield rate. In addition, the presence of cracks during the construction process affects the later delivery of the house. Utility Model Content

[0005] In response to the technical problems existing in the prior art, the present invention provides a high-ductility concrete composite slab based on shape memory alloy, so as to at least to some extent overcome one or more problems caused by the limitations and defects of the above-mentioned prior art.

[0006] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0007] The utility model provides a high-ductility concrete composite plate based on shape memory alloy, comprising a high-ductility concrete bottom plate, a plurality of steel trusses and reinforcement materials;

[0008] The high-ductility concrete base plate is a flat plate of a preset thickness, and a plurality of the steel trusses are arranged in parallel above the high-ductility concrete base plate; wherein the steel trusses are arranged along the length direction of the high-ductility concrete base plate, and the bottoms of the steel trusses are buried inside the high-ductility concrete base plate;

[0009] The reinforcement is arranged in the high-ductility concrete bottom plate along the length direction and placed between two adjacent steel trusses; wherein the reinforcement is a shape memory alloy.

[0010] Furthermore, the steel truss comprises an upper chord, two lower chords and two web members;

[0011] The upper chord is arranged above the high-ductility concrete base plate and along the length direction of the high-ductility concrete base plate; the two web members are arranged in an "eight" shape on both sides of the upper chord, and both web members are made of wavy steel bars with bent legs; the two lower chords are symmetrically arranged below the upper chord;

[0012] The crest of the web is fixedly connected to the upper chord, and the trough of the web is bent toward a side away from the upper chord, and is fixedly connected to a lower chord provided on the same side at the bending point; wherein the bent portions of the lower chord and the web are both embedded in the high-ductility concrete base plate.

[0013] Furthermore, the angle between the web and the horizontal plane is 45°-60°.

[0014] Furthermore, the diameter of the upper chord is 8-16 mm, the diameter of the lower chord is 8-16 mm, and the diameter of the web is 5-8 mm.

[0015] Furthermore, the distance between two adjacent steel bar trusses is 100-200 mm.

[0016] Furthermore, the pre-stretching elongation of the reinforcement is 1%-8%.

[0017] Furthermore, the heating temperature of the reinforcement is 100-450° C., and the recovery stress is 200-500 MPa.

[0018] Furthermore, the diameter of the reinforcement is 5-8 mm.

[0019] Furthermore, the dimensional characteristics of the high-ductility concrete base plate are: length×width×thickness=(1000-6000) mm×(1000-3000) mm×(15-30) mm.

[0020] Furthermore, the surface of the high ductility concrete base plate is roughened.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] The high-ductility concrete composite slab based on shape memory alloy provided by the utility model adopts a high-ductility concrete base plate. Since the thickness of the high-ductility concrete base plate is relatively thin, the weight of the prefabricated components is greatly reduced, the construction difficulty of lifting and installation is reduced, and the cost is reduced; there is no need to extend beard reinforcement around the base plate, and effective connection between the plates can be achieved by overlapping the steel bars, which simplifies the construction process; secondly, by arranging shape memory alloy reinforcement between two adjacent steel trusses, the bonding effect between the shape memory alloy and the high-ductility concrete is utilized, so that the recovery stress of the shape memory alloy will be indirectly converted into prestressed stress inside the high-ductility concrete composite slab, effectively limiting the cracks generated in the composite slab during production, transportation and construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0024] Figure 1 This is a schematic diagram of the planar structure of the high-ductility concrete composite slab based on shape memory alloy provided by the present invention;

[0025] Figure 2 A cross-sectional view of the high-ductility concrete composite slab based on shape memory alloy provided by the present invention;

[0026] Figure 3 It is a cross-sectional view of the steel truss in the present utility model.

[0027] Among them, 1 is a high-ductility concrete base plate, 2 is a steel truss, 3 is a reinforcement, 21 is an upper chord, 22 is a web member, and 23 is a lower chord. DETAILED DESCRIPTION

[0028] In order to make the technical problems, technical solutions, and beneficial effects solved by this application more clearly understood, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application; it is obvious that the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of this application.

[0029] As attached Figure 1-3 As shown, the present invention provides a high-ductility concrete composite plate based on shape memory alloy, including a high-ductility concrete base plate 1, a plurality of steel trusses 2 and reinforcement 3.

[0030] The high-ductility concrete base plate 1 is a flat plate of a preset thickness, which is formed by pressing and plastering high-ductility concrete; preferably, the surface of the high-ductility concrete base plate 1 is roughened to ensure a reliable connection between the high-ductility concrete base plate 1 and the post-cast concrete layer, thereby improving the integrity of the composite plate.

[0031] The high-ductility concrete base plate 1 has the following dimensional characteristics: length × width × thickness = (1000-6000) mm × (1000-3000) mm × (15-30) mm. Preferably, the raw materials of the high-ductility concrete include cement, fly ash, silica fume, sand, PVA fiber, and water; wherein, by mass percentage, the cement: fly ash: silica fume: sand: water = 1:0.9:0.1:0.76:0.58; the volume content of PVA fiber is 1.5%, based on the total volume of the uniformly mixed cement, fly ash, silica fume, sand, and water. Due to the incorporation of PVA fiber, when the high-ductility concrete cracks, the PVA fiber in the crack can transfer tensile stress, thereby limiting the crack width, resulting in a fine and dense crack.

[0032] Several of the steel trusses 2 are arranged in parallel above the high ductility concrete base plate 1, and the bottoms of the steel trusses 2 are buried inside the high ductility concrete base plate 1; wherein, the steel trusses 2 are arranged along the length direction of the high ductility concrete base plate 1, and the spacing between adjacent steel trusses 2 is 100mm-200mm.

[0033] The steel truss 2 includes an upper chord 21, two lower chords 22 and two webs 23; the upper chord 21 is arranged above the high ductility concrete base plate 1 and is arranged along the length direction of the high ductility concrete base plate 1; the two webs 23 are arranged in an eight-shaped shape on both sides of the upper chord 21, and both of the webs 23 use wavy steel bars with bent feet; the two lower chords 22 are symmetrically arranged below the upper chord 21; wherein the crest of the web 23 is fixedly connected to the upper chord 21, and the trough of the web 23 is bent toward the side away from the upper chord 21, and is fixedly connected to the lower chord 22 arranged on the same side at the bending point; wherein the bent parts of the lower chord 22 and the web 23 are buried in the high ductility concrete base plate 1, thereby forming an effective connection between the steel truss 2 and the high ductility concrete base plate 1.

[0034] Specifically, the web member 23 is wavy along the length direction of the high-ductility concrete base plate 1; wherein, the wave crest of the web member 23 is welded to one side of the upper chord member 21, and the wave trough of the web member 23 is bent outward and welded to the lower chord member 22 on the same side at the bending point; preferably, the angle between the web member 23 and the horizontal plane is 45°-60°; the diameters of the upper chord member 21 and the lower chord member 22 are both between 8-16 mm, and the diameter of the web member 23 is between 5-8 mm.

[0035] The reinforcement 3 is arranged in the high-ductility concrete base plate 1 along the length direction and placed between two adjacent steel trusses 2; wherein the reinforcement 3 is a shape memory alloy; it should be noted that the reinforcement 3 made of shape memory alloy can generate a preset recovery stress under heating conditions after pre-stretching; preferably, the pre-stretching elongation of the reinforcement 3 is 1%-8%, and the diameter of the reinforcement 3 is 5-8mm; at a heating temperature of 100-450°C, the recovery stress is 200-500MPa; in terms of weight percentage, the chemical composition of the reinforcement 3 includes: 15% manganese, 5% silicon, 5% nickel, 8% chromium, 0-1% nitrogen, 0-4% vanadium, 0-0.2% carbon and the balance iron.

[0036] The high ductility concrete composite slab based on shape memory alloy described in the present invention is constructed as follows:

[0037] Step 1: Pre-stretch the reinforcement 3 to obtain the pre-stretched reinforcement 3.

[0038] Step 2: prepare high-ductility concrete according to a preset mix ratio requirement; press the high-ductility concrete into a flat plate of a preset thickness to obtain a high-ductility concrete base plate 1.

[0039] Step 3: After the high-ductility concrete is pressed and troweled, the foot of the steel truss 2 is embedded in the high-ductility concrete base plate 1 along the longitudinal direction to effectively connect the steel truss 2 and the high-ductility concrete base plate 1 and form a high-ductility concrete composite plate.

[0040] Step 4: Arrange a pre-stretched reinforcement 3 in the middle of two adjacent steel trusses.

[0041] Step 5: After the curing is completed, the reinforcement 3 is electrically heated to prepare a high-ductility concrete composite plate with prestress, that is, a high-ductility concrete composite plate based on shape memory alloy is obtained.

[0042] Project example description:

[0043] Taking the composite slab in a certain prefabricated building project as an example, the high ductility concrete composite slab based on shape memory alloy is described in detail as follows:

[0044] In this engineering example, the high-ductility concrete base plate 1 has a length of 3000 mm, a width of 1000 mm, and a thickness of 15 mm. The steel trusses 2 are arranged parallel to the top of the high-ductility concrete base plate 1, with a spacing of 200 mm between two adjacent steel trusses 2. In the steel trusses 2, the diameter of the upper chord 21 is 12 mm, the diameter of the lower chord 22 is 8 mm, and the diameter of the web 23 is 5 mm. The reinforcement 3 is arranged in the middle position between adjacent steel trusses 2, and the diameter of the reinforcement 3 is 5 mm.

[0045] The specific construction process is as follows:

[0046] First, the reinforcement is pre-stretched with a stretching elongation of 4% to obtain the pre-stretched reinforcement; high-ductility concrete is mixed according to the mix ratio and pressed into a high-ductility concrete base plate with a length of 3000mm, a width of 1000mm, and a thickness of 15mm; the steel trusses are buried in the high-ductility concrete base plate; then, the pre-stretched reinforcement is buried in the high-ductility concrete base plate and arranged in the middle position of adjacent steel trusses; after the curing is completed, the reinforcement is electrified to be heated to a temperature of 100°C; then, due to the shape memory alloy generating a recovery stress of 200MPa, the bonding effect between the shape memory alloy and the high-ductility concrete base plate is utilized to generate a specific prestress inside the high-ductility concrete composite plate, effectively limiting the cracks generated in the composite plate during production, transportation and construction.

[0047] The high-ductility concrete composite slab based on shape memory alloy described in the present invention utilizes high-ductility concrete to press and form a base plate of preset thickness, arranges steel trusses above the base plate along the length direction, and embeds shape memory alloy reinforcements between two adjacent steel trusses; since the thickness of the high-ductility concrete base plate is relatively thin, the weight of the prefabricated components is greatly reduced, the construction difficulty of hoisting and installation is reduced, and the cost is reduced; since the thickness of the high-ductility concrete base plate is relatively thin, there is no need for reinforcement to extend around the base plate, and the effective connection between the plates can be achieved by overlapping the steel bars, which simplifies the construction process Process; since shape memory alloy is a special metal material with shape memory effect, after pre-stretching, when heated to a certain degree, the shape memory alloy will return to its original shape; if constraints are applied to both ends of the shape memory alloy before heating, recovery stress will be generated inside the shape memory alloy; the shape memory alloy is embedded in the high-ductility concrete composite slab, and the bonding effect between the shape memory alloy and the high-ductility concrete is utilized. The recovery stress of the shape memory alloy will be indirectly converted into prestressed stress inside the high-ductility concrete composite slab, effectively limiting cracks generated in the composite slab during production, transportation and construction.

[0048] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes within the technical scope disclosed by the present invention, any changes, replacements and other implementation methods that can be easily thought of by any technician familiar with this technical field.

Claims

1. A high ductility concrete composite slab based on shape memory alloy, characterized in that: It comprises a high ductility concrete base plate (1), a plurality of steel trusses (2) and reinforcement (3); The high-ductility concrete base plate (1) is a flat plate of a preset thickness, and a plurality of the steel trusses (2) are arranged in parallel above the high-ductility concrete base plate (1); wherein the steel trusses (2) are arranged along the length direction of the high-ductility concrete base plate (1), and the bottoms of the steel trusses (2) are buried inside the high-ductility concrete base plate (1); The reinforcement (3) is arranged in the high-ductility concrete base plate (1) along the length direction and placed between two adjacent steel bar trusses (2); wherein the reinforcement (3) is a shape memory alloy.

2. The high ductility concrete composite slab based on shape memory alloy according to claim 1, characterized in that: The steel truss (2) comprises an upper chord (21), two lower chords (22) and two web members (23); The upper chord (21) is arranged above the high-ductility concrete base plate (1) and along the length direction of the high-ductility concrete base plate (1); the two web members (23) are arranged in an "eight" shape on both sides of the upper chord (21), and both web members (23) use wavy steel bars with bent legs; the two lower chords (22) are symmetrically arranged below the upper chord (21); The crest of the web member (23) is fixedly connected to the upper chord member (21), and the trough of the web member (23) is bent toward a side away from the upper chord member (21) and fixedly connected to a lower chord member (22) arranged on the same side at the bending part; wherein the bent parts of the lower chord member (22) and the web member (23) are both embedded in the high-ductility concrete base plate (1).

3. The high ductility concrete composite slab based on shape memory alloy according to claim 2, characterized in that: The angle between the web (23) and the horizontal plane is 45°-60°.

4. The high ductility concrete composite slab based on shape memory alloy according to claim 2, characterized in that: The diameter of the upper chord (21) is 8-16 mm, the diameter of the lower chord (22) is 8-16 mm, and the diameter of the web (23) is 5-8 mm.

5. The high ductility concrete composite slab based on shape memory alloy according to claim 1, characterized in that: The distance between two adjacent steel bar trusses (2) is 100-200 mm.

6. The high ductility concrete composite slab based on shape memory alloy according to claim 1, characterized in that: The pre-stretching elongation of the reinforcement (3) is 1%-8%.

7. The high ductility concrete composite slab based on shape memory alloy according to claim 1, characterized in that: The heating temperature of the reinforcement material (3) is 100-450° C., and the recovery stress is 200-500 MPa.

8. The high ductility concrete composite slab based on shape memory alloy according to claim 1, characterized in that: The diameter of the reinforcement (3) is 5-8 mm.

9. The high ductility concrete composite slab based on shape memory alloy according to claim 1, characterized in that: The dimensional characteristics of the high-ductility concrete base plate (1) are: length×width×thickness=(1000-6000) mm×(1000-3000) mm×(15-30) mm.

10. The high ductility concrete composite slab based on shape memory alloy according to claim 1, characterized in that: The surface of the high-ductility concrete base plate (1) is roughened.

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