A composite floor
By combining prefabricated plates without steel bars with cast-in-place reinforced concrete superimposed layer, combined with cement-based thermal insulation prefabricated plates and nano-silicon expanded resin particles, the problem of excessive thickness of prefabricated plates on the stacked floor is solved, and construction efficiency and floor functions are improved reduces cost and thickness.
Patent Information
- Application Number
- CN202411287924.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-14
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2044-09-14
AI Technical Summary
The thickness of the existing superimposed floor slabs is too large, resulting in high construction costs and low efficiency, and it is difficult to meet the functional needs of modern buildings for thermal insulation, sound insulation, etc.
The prefabricated plate without steel bars is combined with the cast-in-place reinforced concrete superimposed layer. The prefabricated layer is used as the bottom mold of the superimposed layer. The tensile steel bars are directly in contact with the prefabricated layer or have a spacing. The prefabricated layer is made of cement-based thermal insulation prefabricated plate. The overlap layer is composed of alkali-resistant glass fiber mesh cloth and cement slurry, and the nano-silicon puffed resin particles are used to improve the flexural strength.
The thickness of prefabricated plates is reduced, the assembly efficiency and construction convenience are improved, the cost of floor slabs is reduced, the net height of floors is increased, the structural composition is simplified, and the prefabricated plates are easier to be embedded in water and electricity pipelines. The prefabricated plates are lighter and thinner, making them easy to transport and install.
Smart Images
Figure CN118815044B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of assembled building construction methods, and in particular relates to a composite floor slab. Background Art
[0002] The existing traditional floor slabs include the following types:
[0003] 1. Traditional cast-in-place concrete floor:
[0004] like Figure 1 As shown, the process of cast-in-place concrete floor 2 is: erecting formwork on site → erecting first tension reinforcement 21 on the formwork (the distance between the first tension reinforcement 21 and the bottom formwork is not less than 15 mm) → pouring concrete to form a first concrete layer 23 (so that the thickness of the first protective layer 22 below the first tension reinforcement 21 embedded in the first concrete layer 23 meets the minimum thickness requirement of the concrete protective layer in the national standard, which is not less than 15 mm) → removing the formwork to form a cast-in-place concrete floor 2.
[0005] This method is the most traditional floor construction method. All construction work is completed on site, including on-site template cutting, on-site steel bar cutting, steel bar tying, concrete pouring, etc. The advantage of this process structure is that the structure is simple and reliable, which is the basis of all current floor construction methods. The disadvantages are: a. The requirements of a single structure can no longer meet the functional requirements of current national policies such as floor insulation and floor sound insulation; b. It requires a large number of on-site workers, which is difficult to manage and does not conform to the direction of national industrialization and high-end manufacturing;
[0006] 2. Traditional composite floor 3:
[0007] like Figure 3 As described above, the traditional composite floor 3 is a traditional cast-in-place concrete floor 2 divided from the middle to the upper and lower parts into a traditional composite layer and a traditional precast panel 31. The traditional precast panel 31 is cast in the factory through a formwork. During casting, the second tensile steel bar 34 is raised, and the distance between the second tensile steel bar 34 and the bottom form and the thickness of the second protective layer 35 meet the minimum thickness requirement of the concrete protective layer in the national standard, which is not less than 15 mm. Then, concrete is cast to form the traditional precast panel 31, and then the traditional precast panel 31 is transported to the site after it is manufactured. Figure 4 As shown, the composite layer steel bars 33 are installed at the construction site, and then the conventional precast panel 31 is used as a bottom form to cast concrete to form a conventional composite floor slab 3.
[0008] The advantage of this process is that the tasks of tying part of the steel bars of the floor slab and pouring part of the concrete are transferred from the construction site to the factory for prefabrication, which is in line with the national policy orientation.
[0009] The disadvantage of this process is that compared with cast-in-place concrete slabs, the slab structure is more complicated, so the thickness of the slab is thicker. Specifically, the thickness of the traditional cast-in-place concrete slab is usually 100mm to meet the national standard. For large bays, kitchens and bathrooms, the thickness of the fully cast-in-place concrete slab only needs 110mm to 120mm to meet the national standard. If the traditional composite slab process is adopted, the current national standard stipulates that the thickness of the prefabricated layer should not be less than 60mm, and the thickness of the composite layer should not be less than 70mm. In this way, the overall thickness of the traditional composite slab reaches 130mm. On the one hand, the thickness of the traditional prefabricated slab is thick, and the overall weight of the internal steel bars is large, which makes it difficult to transport. On the one hand, it is difficult to transport, hoist and lay. On the other hand, the excessive thickness will cause the final composite floor to occupy the space of the room, which significantly reduces the headroom in the room. Moreover, since the traditional prefabricated panels reach 60mm, the overall thickness of the composite floor can only be reduced by reducing the thickness of the composite layer to a minimum. Therefore, the thickness of the traditional composite layer is generally only 70mm, which is not convenient for pre-buried water and electricity pipelines in the composite layer. It can be seen that the traditional composite floor not only fails to give full play to the advantages of prefabricated floors, but also the construction cost is about 90 yuan / ㎡ higher than the traditional cast-in-place floors. The overall thickness is thicker than the traditional cast-in-place concrete floors. The structural process cannot meet the current national requirements for floor insulation and sound insulation.
[0010] 3. Insulated steel bar truss floor deck 4:
[0011] like Figure 5 , 6 As shown, the insulation steel bar truss floor slab 4 includes an insulation bottom plate 41, and the truss steel bars 43 are embedded and fixed in the insulation bottom plate 41. The insulation bottom plate 41 serves as a template layer and an insulation structure layer, and the truss steel bars 43 can replace the steel bars of part of the floor structure layer. After the insulation steel bar truss floor slab 4 is installed on site, the third tensile steel bars 44 are tied on site. The thickness of the third tensile steel bars 44 from the insulation bottom plate 41, i.e., the third protective layer 45, meets the minimum thickness requirement of the concrete protective layer in the national standard, which is not less than 15 mm. Then, concrete is poured on the insulation bottom plate 41 to form the third concrete layer 42. It can be seen that the difference between the insulation steel bar truss floor slab 4 and the cast-in-place concrete floor slab is that a. the insulation bottom plate 41 is only used as a structural member, not a structural member; b. the insulation bottom plate 41 is not disassembled after being used as a template, and is directly used as an insulation structure layer, so that the floor slab also has an insulation function.
[0012] The advantages of this structure are: the floor insulation is combined with the traditional cast-in-place floor structure, so that the floor and insulation are integrated. The disadvantages are: the insulation bottom plate 41 is relatively heavy and can only be hoisted by a tower crane, and the installation speed is slow; the insulation bottom plate 41 is only an insulation layer and cannot be counted as part of the floor structure and requires a steel truss to provide the bottom plate strength. This part of the steel truss can only be partially counted as structural steel bars. The thickness of the floor is thick, which greatly increases the amount of steel bars used in the entire floor structure, increasing the cost of the entire floor.
[0013] Through the above analysis, all the theoretical basis and calculation methods of concrete structure building design in China are derived from the "Concrete Structure Design Standard" (GB50010). This standard is the basic rule for concrete structure design and construction. The standard stipulates that the minimum thickness of the steel bar protection layer shall not be less than 15mm, which is a red line. Therefore, the design of traditional composite floor slabs is derived from this standard. According to the standard requirements, in order to meet the requirements of the steel bar protection layer thickness of 15mm and the minimum thickness limit of 50mm for the concrete precast slab in GB50010, the thickness of the traditional precast slab 31 prefabricated in the factory is at least 60mm. On the one hand, the increase in the thickness of the traditional precast slab 31 leads to an increase in the weight of the traditional precast slab 31, making the transportation and assembly of the traditional precast slab difficult. On the other hand, the increase in the thickness of the traditional precast slab 31 will occupy the thickness of the post-cast composite layer 32, making it difficult to pre-bury the water and electricity pipelines in the later stage, and the overall thickness of the slab will not be less than 130mm, which is still much higher than the cast-in-place concrete slab 2.
[0014] As building assembly, industrialization and integration have always been the focus of national guidance and support, composite floor slabs, as an important part of building assembly, are still the mainstream technical solution on the market. Compared with traditional concrete structure floors, although they have the advantages of assembly and integration, the existing composite slab system is more complex, has higher construction costs and greater construction difficulty than traditional structures. Therefore, there is an urgent need for a new composite slab structure system that can meet the needs of industrialization, assembly, prefabrication, and functional integration (integration of structure and insulation), while reducing costs, improving construction convenience, and improving construction efficiency. Summary of the invention
[0015] The technical problem to be solved by the present invention is to provide a composite floor slab which reduces the thickness of prefabricated panels in the composite floor slab, improves the assembly efficiency of the prefabricated panels, and improves the construction convenience.
[0016] The present invention discloses a composite floor slab, comprising a prefabricated layer and a composite layer, wherein the prefabricated layer is formed by splicing prefabricated panels without steel bars, the composite layer is a cast-in-place reinforced concrete structure, and the prefabricated layer is used as a bottom form when the composite layer is cast, and the tensile steel bars in the composite layer are directly in contact with the upper surface of the prefabricated layer or have a spacing with the upper surface of the prefabricated layer.c 0; the cross-sectional height of the composite floor is h´ , the effective height of the composite floor section is h 0 ´ The thickness of the prefabricated layer is t , the diameter of the tensile reinforcement is d , the distance between the tensile reinforcement and the upper surface of the precast layer is c 0, the distance from the edge of the tension zone of the composite floor to the point where the combined force of the tension reinforcement is defined as a s1 ;
[0017] a s1 = h´-h 0 ´ ;
[0018] a s1 ≥a s ;
[0019] a s1 = t + d / 2+ c 0;
[0020] when 15mm ≤ c≤25mm hour, 0 ≤ c 0 ≤5mm ;
[0021] when 25mm < c≤40mm hour, 5mm ≤ c 0 ≤10mm ;
[0022] in a s is the distance from the edge of the tension zone to the point of action of the combined force of the tension reinforcement in the cast-in-place concrete structure. c It is the minimum thickness of the concrete protective layer in the "Concrete Structure Design Standard (GB50010)".
[0023] In this embodiment, the heat transfer coefficient K of the composite floor slab is ≤1.8 W / ㎡•K. The heat transfer coefficient K is calculated using the JGJ / 134 standard.
[0024] In the above embodiment, the thickness t of the prefabricated layer is 15 mm to 30 mm.
[0025] In the above implementation manner, the present application has the following three implementation manners:
[0026] when 15mm ≤ c≤25mm hour, c 0=0mm.
[0027] when 15 mm ≤ c≤25 mm When or 25 mm< c≤40 mm, c 0=5mm.
[0028] when 25mm < c≤40mm hour, c 0=10mm.
[0029] Through three implementation methods, different environmental categories in construction standards can be adapted.
[0030] In this embodiment, the linear expansion coefficient of the prefabricated layer is 0.8*10 -5 ~1.8*10 -5 , steel bar corrosion weight loss rate ≤ 2%. The linear expansion coefficient is tested according to the "Concrete Physical and Mechanical Properties Test Method Standard" GB / T50081; the steel bar corrosion weight loss rate is tested according to the "Ordinary Concrete Long-term Performance and Durability Test Method Standard" GB / T50082.
[0031] In this embodiment, the prefabricated layer is formed by splicing a plurality of prefabricated panels, the splicing surfaces of adjacent prefabricated panels are in close contact, and adjacent prefabricated panels are connected by an overlapping layer arranged on the lower surface of the splicing seam, and the overlapping layer is a sandwich structure formed by coating cement slurry on the upper and lower surfaces of alkali-resistant glass fiber mesh cloth;
[0032] In this embodiment, the width of the overlapping layer is 100 mm to 300 mm.
[0033] In this embodiment, the prefabricated board is selected from cement-based thermal insulation prefabricated board; the cement-based thermal insulation prefabricated board comprises a thermal insulation structure layer, an upper surface reinforcement layer and a lower surface reinforcement layer, the thermal insulation structure layer is located between the upper and lower surface reinforcement layers, and the thermal insulation structure layer is fixedly connected to the upper surface reinforcement layer and the lower surface reinforcement layer;
[0034] In this embodiment, the upper surface reinforcement layer and the lower surface reinforcement layer are formed by coating cement slurry on the alkali-resistant glass fiber mesh cloth; the thermal insulation structure layer is formed by mixing and flattening the cement-based thermal insulation slurry and vibrating it;
[0035] In this embodiment, the cement-based thermal insulation slurry comprises the following components: cement dry material, functionalized coupling agent, hydroxypropyl methylcellulose, rubber powder, rice husk, and nano-silicon expanded resin particles; 2-3g of the functionalized coupling agent, 2-3g of hydroxypropyl methylcellulose, 15-30g of rubber powder, 60-80g of rice husk, and 20-40g of nano-silicon expanded resin particles are added to each kilogram of cement dry material; the functionalized coupling agent is selected from one of kH570 silane coupling agent and DL-411 aluminate coupling agent;
[0036] In this embodiment, the nano-silicon expanded resin particles are prepared by the following method:
[0037] Step 1: ingredients: 100 parts of styrene, 2-5 parts of nano-silicon powder, 0.3-0.5 parts of benzoyl peroxide (BPO), 0.04-0.08 parts of tert-butyl perbenzoate (T-BPB), 0.05-0.1 parts of hydroxyethyl cellulose (HEC), 0.3-0.5 parts of tricalcium phosphate (TCP), 0.02 parts of sodium pyrophosphate, and 8 parts of pentane;
[0038] In the second step, 115-125 parts of deionized water are added to the reactor, and styrene, nano silicon powder, benzoyl peroxide, tert-butyl perbenzoate, and sodium pyrophosphate are added to the reactor according to the component proportions determined in the first step, and 40-60% of the hydroxyethyl cellulose and tricalcium phosphate proportions determined in the first step are added at a constant temperature of 85-95° C. with stirring, and polymerization reaction is carried out. After the reaction for 3-4 hours, 20-30% of the hydroxyethyl cellulose and tricalcium phosphate proportions determined in the first step are added to the reactor, and the constant temperature reaction is continued for 3-4 hours. Finally, 20-30% of the hydroxyethyl cellulose and tricalcium phosphate proportions determined in the first step and pentane are added to the reactor, the pressure in the reactor is controlled to be ≤1.0Mpa, the temperature is raised to 115-130° C., maintained for 3-4 hours, and the material is cooled to below 30-50° C. for discharge, and the material is dehydrated and dried to obtain nano silicon expanded resin particles.
[0039] In this embodiment, in the second step, the material is dehydrated and dried and then stirred in a powder coating agent for 1-4 minutes to obtain nano-silicon expanded resin particles; the coating agent includes the following components in mass percentage: monoglyceride 9-11%, diglyceride 18-22%, and zinc stearate 68-72%.
[0040] In this embodiment, the cement-based thermal insulation prefabricated board is prepared by the following method: applying cement slurry on the mesh cloth to form a lower surface reinforcement layer; then the cement-based thermal insulation slurry is stirred evenly, spread and arranged on the lower surface reinforcement layer, vibrated, dried and formed to obtain a thermal insulation structure layer; finally, a mesh cloth is laid on the thermal insulation structure layer and cement slurry is applied on the mesh cloth, and dried naturally to obtain a cement-based thermal insulation prefabricated board; further, the thermal conductivity coefficient λ of the cement-based thermal insulation prefabricated board is ≤0.09W / m•K. The thermal conductivity coefficient λ is tested according to GB / T 10294 standard.
[0041] Due to the adoption of the above structure and method, the present invention has the following advantages:
[0042] 1. The present application replaces or partially replaces the structural area in the cast-in-place concrete with a prefabricated layer, and at the same time uses the prefabricated layer as a template for the cast-in-place composite layer, and sets the tensile steel bars in the composite layer to facilitate subsequent construction. Through such a setting, the present invention can select prefabricated panels with different functions as prefabricated layers, and can optimize the functionality of the composite floor slab, so that the prefabricated layer is both a structural layer and a functional layer on the one hand. After the construction of the composite floor slab is completed, the floor slab achieves the effect of structural and functional integration. On the other hand, compared with the prefabricated panels in traditional composite floors, the thickness is greatly reduced, and the prefabricated panels are lighter and thinner, making on-site vertical and horizontal transportation more convenient. Horizontal transportation and installation can be carried out manually or by tower crane installation. It is no longer like traditional prefabricated panels that can only rely on tower crane installation, which significantly increases the construction efficiency. After the on-site installation is completed, the composite floor slab can be formed by tying steel bars and pouring concrete on the prefabricated panels; and because the thickness of the prefabricated layer is reduced, the thickness of the composite layer can be increased, thereby facilitating the construction of pre-buried water and electricity pipelines.
[0043] 2. The present application simplifies the structure of the composite floor slab; compared with the traditional composite floor slab, the prefabricated layer of the present application no longer bears the main structural tension, and there is no truss steel bar for structural stability between the prefabricated layer and the composite layer, which simplifies the structural composition and makes the prefabricated panels lighter and thinner; the prefabricated panels of the prefabricated layer can be made 15-30mm thick, which is convenient for the transportation and installation of the prefabricated layer; the prefabricated layer of the present application is thin and can be equivalent to the cast-in-place concrete floor slab, and the net height of the floor is increased compared with the traditional composite floor slab.
[0044] 3. Compared with traditional composite floors, this application does not have structural steel bars, reduces the thickness of the floor, saves steel bars, concrete materials and labor costs, reduces the floor insulation layer, and reduces the cost of composite floors.
[0045] 4. The present application simplifies the connection measures between prefabricated panels. Since the prefabricated layer no longer bears the main structural tension, the adjacent prefabricated panels are installed with the joint surfaces close together. They are only connected by overlapping layers on the lower side of the joints of the adjacent prefabricated panels. Compared with the traditional method of connecting the traditional composite floor slabs through reserved post-cast strips, the construction is simple, convenient and low-cost.
[0046] 5. The minimum thickness of mainstream composite floor slabs on the market is 130mm if the standards are met. However, in this application, since the load-bearing structure is concentrated in the composite layer, the prefabricated layer only needs to meet the minimum requirements of the standard for the steel bar protective layer. If the standards are met, the minimum thickness of the composite floor slab of this application can be made to be 100mm.
[0047] 6. This application reduces the cost of composite floor slabs. The new composite floor slab structure has no truss steel bars in the prefabricated layer. The prefabricated layer and the composite layer do not need structural distribution bars, which greatly saves the amount of steel bars. The composite floor slab of this application is thinner than the traditional composite floor slab, which greatly saves the amount of concrete. The installation method is simpler than the traditional floor slab. It saves materials and labor, and the cost is lower than the traditional composite floor slab.
[0048] 7. The prefabricated board of the present application improves the flexural strength and load-bearing performance of the entire prefabricated board by adding nano-silicon expanded resin particles and functionalized coupling agents to the cement-based insulation board. At the same time, due to the effect of the functionalized coupling agent, the prefabricated board can be more firmly combined with the steel bars, and the prefabricated layer can be more tightly combined with the laminated layer; thus, the tightness and reliability of the combination between the prefabricated layer, the laminated layer and the steel bars are further improved; so that the prefabricated layer can serve as a protective layer for the steel bars.
[0049] In summary, the composite floor slab of the present invention reduces the thickness of the prefabricated slabs in the composite floor slab, making the construction of the composite floor slab more convenient, shortening the construction period, and improving the work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0050] Figure 1 This is a structural diagram of a traditional cast-in-place concrete floor.
[0051] Figure 2 This is a schematic diagram of the force division of traditional cast-in-place concrete slabs, where:
[0052] a is the force division diagram of the rectangular section of the traditional concrete floor;
[0053] b is the stress analysis diagram of the rectangular section of the traditional concrete floor.
[0054] Figure 3 This is a schematic diagram of the structure of precast panels in traditional composite floors.
[0055] Figure 4 This is a structural diagram of a traditional composite floor.
[0056] Figure 5 It is a structural schematic diagram of the bottom plate in the existing thermal insulation steel truss floor deck.
[0057] Figure 6 It is a structural schematic diagram of the existing thermal insulation steel truss floor deck.
[0058] Figure 7 It is a structural schematic diagram of the composite floor of the present invention.
[0059] Figure 8 It is a structural schematic diagram of Example 1 of the composite floor of the present invention.
[0060] Fig. 9 It is a structural schematic diagram of Example 2 of the composite floor of the present invention.
[0061] Fig.10 This is a schematic structural diagram of Example 3 of the composite floor of the present invention.
[0062] In the figure: 1. Composite slab; 11. Composite layer; 12. Precast layer; 13. Tensile reinforcement; 14. Overlap layer; 2. Traditional cast-in-place concrete slab; 21. First tensile reinforcement; 22. First protective layer; 23. First concrete layer; 3. Traditional composite slab; 31. Traditional precast slab; 32. Second concrete layer; 33. Composite layer reinforcement; 34. Second tensile reinforcement; 35. Second protective layer; 4. Insulated steel truss floor slab; 41. Insulated bottom slab; 42. Third concrete layer; 43. Truss reinforcement; 44. Third tensile reinforcement; 45. Third protective layer; DETAILED DESCRIPTION
[0063] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0064] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.
[0065] like Figures 7 to 10As shown, a composite floor 1 comprises a prefabricated layer 12 and a composite layer 11, wherein the prefabricated layer 12 is formed by splicing prefabricated panels without steel bars, the composite layer 11 is a cast-in-place reinforced concrete structure, and the prefabricated layer 12 serves as a bottom form when pouring the composite layer 11, and the tensile steel bars 13 in the composite layer 11 are directly in contact with the upper surface of the prefabricated layer 12 or are spaced apart from the upper surface of the prefabricated layer 12. c 0; the cross-sectional height of the composite floor 1 is h´ , the effective height of the section of composite floor 1 is h 0 ´ , the thickness of the prefabricated layer 12 is t , the diameter of the tensile reinforcement 13 is d , the distance between the tension steel bar 13 and the upper surface of the prefabricated layer 12 is c 0, the distance from the edge of the tension zone of the composite floor 1 to the point of action of the resultant force of the tension steel bar 13 is defined as a s1 ;
[0066] a s1 = h´-h 0 ´ ;
[0067] a s1 ≥a s ;
[0068] a s1 = t + d / 2+ c 0;
[0069] when 15mm ≤ c≤25mm hour, 0 ≤ c 0 ≤5mm ;
[0070] when 25mm < c≤40mm hour, 5mm ≤ c 0 ≤10mm ;
[0071] in a s1 is the distance from the edge of the tension zone of the composite floor slab 1 to the point of action of the resultant force of the tension reinforcement 13, a s is the distance from the edge of the tension zone to the point of action of the combined force of the tension reinforcement 13 in the cast-in-place concrete structure, c It is the minimum thickness of the concrete protective layer in the "Concrete Structure Design Standard" (GB50010).
[0072] By adopting the above structure, the present invention actually re-splits and redesigns the structure of the traditional cast-in-place concrete floor 2 to form a new composite floor 1. Specifically: Figure 1 , 2 As shown, the present invention divides the traditional cast-in-place concrete floor 2 into stress-bearing areas ( h 0 area) and the structural area ( a s area), h 0 is the effective height of the cross section of the traditional cast-in-place concrete floor 2, a s is the distance from the edge of the tensile zone of the traditional cast-in-place concrete floor 2 to the point of action of the combined force of the tensile steel bars 13 (specifically: a s is the distance from the central axis of the steel bar to the bottom surface of the traditional cast-in-place concrete floor slab 2, h 0 is the distance from the center axis of the steel bar to the top surface of the traditional cast-in-place concrete slab 2);
[0073] The reason why the traditional cast-in-place concrete floor 2 is divided into stress zones ( h 0 area) and the structural area ( a s area), because when designing the traditional cast-in-place concrete floor 2, the cross-sectional height of the traditional cast-in-place concrete floor 2 h It is determined according to the following method;
[0074] like Figure 1 , 2 As shown in the figure, since the cross section is in a static equilibrium state at the moment before failure, Figure 2 The stress state can establish two equilibrium equations:
[0075] One is that the resultant force of all forces in the horizontal axis direction is zero, that is
[0076] (4-1)
[0077] Where b is the width of the rectangular section;
[0078] —Cross-sectional area of longitudinal reinforcement in tension zone.
[0079] The other is that the resultant moment of all forces on any point on the cross section is zero. When the moment is taken at the point of action of the resultant force on the longitudinal reinforcement in the tension zone, we have
[0080] (4-2)
[0081] When taking the moment at the point of action of the resultant compressive stress of concrete in the compression zone, we have
[0082] (4-3)
[0083] In the formula M —Design value of the bending moment produced by the load on the cross section;
[0084] h 0—Effective height of the section, press Calculate
[0085]
[0086] h is the section height, a s It is the distance from the edge of the tensile zone of the floor slab to the point of action of the resultant force of the tensile reinforcement 13.
[0087] From the above two equilibrium equations, we can know that in the mechanical calculation of the traditional cast-in-place concrete floor 2, a s It does not participate in the force calculation. It can be seen that the division of the force zone and the structural zone according to this application is accurate. The force zone mainly guarantees the structural performance of the floor slab, such as the earthquake resistance, bending resistance, and bearing capacity of the floor slab; the structural zone does not participate in the force calculation of the structure, but mainly participates in the coordinated force of the floor slab while ensuring the performance, such as crack resistance, steel bar corrosion prevention, and ensuring the overall force of steel bars and concrete;
[0088] Although traditional cast-in-place concrete floor slabs 2 have h 0 and a s However, in the existing traditional inertial thinking, there is no concept of separately setting up the stress zone and the structural zone. The traditional cast-in-place concrete floor 2 is cast in one piece, while for the composite floor 3, the prefabricated board covers the entire structural area and part of the stress zone. Therefore, the present application overcomes the limitations of the existing traditional thinking and replaces or partially replaces the structural area in the traditional cast-in-place concrete with the prefabricated layer 12. This is the innovation of the present invention.
[0089] Furthermore, the thickness t of the prefabricated layer 12 of the present application is between 15 mm and 30 mm, and according to the "Concrete Structure Design Standard" (GB50010), the thickness generally increases by 5 mm. Therefore, the thickness of the prefabricated layer 12 of the present application is preferably 15 mm, 20 mm, 25 mm or 30 mm. In actual use, the prefabricated panels can be prefabricated into the above four models in the factory, and then different models can be selected according to the actual needs of the site and transported to the site for assembly to form the prefabricated layer 12.
[0090] As a new type of composite floor slab 1, under the above conditions, the composite floor slab 1 of the present application can be formed into the following three specific implementation methods in actual use to adapt to different use environment categories in the "Concrete Structure Design Standard" (GB50010): Embodiment 1:
[0091] like Figure 8 As shown in the "Concrete Structure Design Standard" (GB50010), when 15mm ≤ c≤25mm When the composite floor slab 1 of the present application c 0=0mm. In this embodiment, the prefabricated layer 12 is used as a bottom form when pouring the composite layer 11. The composite layer 11 is formed by placing the tensile steel bars 13 directly on the prefabricated layer 12 and then pouring concrete. Embodiment 2:
[0092] like Fig. 9 As shown in the "Concrete Structure Design Standard" (GB50010), when 15mm ≤ c≤25mm When or 25 mm< c≤40 mm, c 0=5mm. The difference between this embodiment and Embodiment 1 is that the composite layer 11 is formed by raising the tensile steel bars 13 by 5mm on the prefabricated layer 12 and then pouring concrete. Embodiment 3:
[0093] like Fig.10 As shown in the "Concrete Structure Design Standard" (GB50010), when 25mm < c≤40mm hour, c 0=10mm. The difference between this embodiment and embodiment 1 is that the composite layer 11 is formed by raising the tensile steel bars 13 on the prefabricated layer 12 by 10mm and then pouring concrete.
[0094] In the above three embodiments, the linear expansion coefficient of the prefabricated layer 12 is 0.8*10 -5 ~1.8*10 -5 , steel bar corrosion weight loss rate ≤ 2%. The linear expansion coefficient is tested according to the "Concrete Physical and Mechanical Properties Test Method Standard" GB / T50081; the steel bar corrosion weight loss rate is tested according to the "Ordinary Concrete Long-term Performance and Durability Test Method Standard" GB / T50082; and the heat transfer coefficient K of the manufactured composite floor 1 is ≤ 1.8W / ㎡•K.
[0095] On the basis of the limitations of Examples 1, 2, and 3, and under the same design conditions, the floor thickness, steel content, and concrete usage of the composite floor slab 1 of the present application are compared with those of the cast-in-place concrete floor slab 2 and the traditional composite floor slab 3, as shown below:
[0096] Comparative Example 1:
[0097] The design standard is: "Concrete Structure Design Standard" GB50010;
[0098] Design value: dead load 1.6KN / ㎡, live load 2.5KN / ㎡;
[0099] Set the environment category to one, c =15mm;
[0100] Assume the floor size is: 8000mm×4000mm;
[0101] The steel bars selected are: HRB400;
[0102] The concrete selected is: C30;
[0103] Calculation software: Yingjianke V5.3.0 and PKPM-PC;
[0104] The calculation results are shown in Table 1:
[0105]
[0106] Comparative Example 2:
[0107] The design standard is: "Concrete Structure Design Standard" GB50010;
[0108] Design value: dead load 1.6KN / ㎡, live load 2.5KN / ㎡;
[0109] Set the environment category to Class IIa. c =20mm;
[0110] Assume the floor size is: 8000mm×4000mm;
[0111] The steel bars selected are: HRB400;
[0112] The concrete selected is: C30;
[0113] Calculation software: Yingjianke V5.3.0 and PKPM-PC;
[0114] The calculation results are shown in Table 2:
[0115]
[0116] It can be seen from comparative examples 1 and 2 that, under the condition of meeting the same design requirements, compared with the traditional composite floor slab 3, the composite floor slab 1 of the present application can be thinner, use less concrete, and have a lower steel content, thus having significant structural advantages. Embodiment 4:
[0117] like Figure 7 , 8 As described in , 9 and 10, according to the actual construction situation, the prefabricated layer 12 of the present application is formed by splicing multiple prefabricated panels. Since the prefabricated layer 12 no longer bears the main structural tension, the lower surfaces of adjacent prefabricated panels at the splicing seam are directly connected by the overlapping layer 14. The overlapping layer 14 connects the two adjacent prefabricated panels into a whole and bears the force. The overlapping layer 14 is a sandwich structure composed of cement slurry coated on the upper and lower surfaces of the alkali-resistant glass fiber mesh cloth. The width of the overlapping layer 14 is 100mm to 300mm, which eliminates the post-casting strips between traditional prefabricated panels, greatly improves construction efficiency, and reduces construction costs. Embodiment 5:
[0118] Furthermore, the difference between this embodiment and embodiments 1, 2, 3, and 4 is that the prefabricated board adopts a cement-based thermal insulation prefabricated board, and the cement-based thermal insulation prefabricated board includes an thermal insulation structure layer, an upper surface reinforcement layer, and a lower surface reinforcement layer. The thermal insulation structure layer is located between the upper and lower surface reinforcement layers, and the thermal insulation structure layer is fixedly connected to the upper surface reinforcement layer and the lower surface reinforcement layer.
[0119] The upper and lower surface reinforcement layers of the cement-based thermal insulation prefabricated board are formed by coating cement slurry on an alkali-resistant glass fiber mesh cloth; the thermal insulation structure layer is formed by evenly stirring, flattening, and vibrating the cement-based thermal insulation slurry.
[0120] Furthermore, the cement-based thermal insulation slurry includes the following components: cement dry material, functionalized coupling agent, hydroxypropyl methylcellulose, rubber powder, rice husk, and nano-silicon expanded resin particles; 2-3g of the functionalized coupling agent, 2-3g of hydroxypropyl methylcellulose, 15-30g of rubber powder, 60-80g of rice husk, and 20-40g of nano-silicon expanded resin particles are added to each kilogram of cement dry material; the functionalized coupling agent is selected from one of kH570 silane coupling agent and DL-411 aluminate coupling agent.
[0121] The nano-silicon expanded resin particles are prepared by the following method:
[0122] Step 1: ingredients: 100 parts of styrene, 2-5 parts of nano-silicon powder, 0.3-0.5 parts of benzoyl peroxide (BPO), 0.04-0.08 parts of tert-butyl perbenzoate (T-BPB), 0.05-0.1 parts of hydroxyethyl cellulose (HEC), 0.3-0.5 parts of tricalcium phosphate (TCP), 0.02 parts of sodium pyrophosphate, and 8 parts of pentane;
[0123] In the second step, 115-125 parts of deionized water are added to the reactor, and styrene, nano silicon powder, benzoyl peroxide, tert-butyl perbenzoate, and sodium pyrophosphate are added to the reactor according to the component proportions determined in the first step. At the same time, 40-60% of the hydroxyethyl cellulose and tricalcium phosphate proportions determined in the first step are added, and the temperature is raised to 85-95° C. for constant temperature polymerization reaction. After the reaction is carried out for 3-4 hours, 20-30% of the hydroxyethyl cellulose and tricalcium phosphate proportions determined in the first step are added to the reactor, and the constant temperature reaction is continued for 3-4 hours. 4 hours, finally, add the hydroxyethyl cellulose determined in the first step, 20-30% of the tricalcium phosphate content and pentane into the reactor, control the pressure in the reactor to be ≤1.0Mpa, heat to 115-130°C, maintain for 3-4 hours, cool to below 30-50°C and discharge, dehydrate and dry the material, and then stir it in a powder coating agent for 1-4 minutes to obtain nano-silicon expanded resin particles; the coating agent includes the following components by mass percentage: monoglyceride 9-11%, diglyceride 18-22%, and zinc stearate 68-72%.
[0124] The above cement-based thermal insulation prefabricated board is prepared according to the following method:
[0125] Cement slurry is applied on the mesh cloth to form a lower surface reinforcement layer; then the cement-based thermal insulation slurry is stirred evenly, spread and arranged on the lower surface reinforcement layer, vibrated, dried and formed to obtain a thermal insulation structure layer; finally, mesh cloth is laid on the thermal insulation structure layer and cement slurry is applied on the mesh cloth, dried naturally to obtain a cement-based thermal insulation prefabricated board. The thermal conductivity of this cement-based thermal insulation prefabricated board is λ≤0.09W / m•K.
[0126] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.
Claims
1. A composite floor slab, comprising a prefabricated layer and a composite layer, characterized in that: The prefabricated layer is formed by splicing prefabricated panels without steel bars, the laminated layer is a cast-in-place reinforced concrete structure, and the prefabricated layer serves as a bottom form when pouring the laminated layer. The tensile steel bars in the laminated layer are directly in contact with the upper surface of the prefabricated layer or are spaced apart from the upper surface of the prefabricated layer. There is no truss reinforcement between the prefabricated layer and the laminated layer, and the cross-sectional height of the laminated floor is , the effective height of the composite floor section is The thickness of the prefabricated layer is , the diameter of the tensile reinforcement is , the distance between the tensile reinforcement and the upper surface of the precast layer is , the distance from the edge of the tension zone of the composite floor to the point where the combined force of the tension reinforcement acts is defined as ; ； ； ； when hour, ; when hour, ; in is the distance from the edge of the tension zone to the point of action of the combined force of the tension reinforcement in the cast-in-place concrete structure. It is the minimum thickness of the concrete cover in the "Concrete Structure Design Standard".
2. A composite floor slab according to claim 1, characterized in that: The heat transfer coefficient of the composite floor .
3. A composite floor slab according to claim 1, characterized in that: The thickness of the prefabricated layer It is 15mm~30mm.
4. A composite floor slab according to claim 1, characterized in that: when hour, .
5. The composite floor slab according to claim 1, characterized in that: when When or hour, .
6. The composite floor slab according to claim 1, characterized in that: when hour, .
7. A composite floor slab according to any one of claims 1 to 6, characterized in that: The linear expansion coefficient of the prefabricated layer is , the weight loss rate of steel bar corrosion is ≤2%.
8. The composite floor slab according to claim 7, characterized in that: The prefabricated layer is formed by splicing multiple prefabricated panels, the splicing surfaces of adjacent prefabricated panels are tightly attached, and the adjacent prefabricated panels are connected by an overlapping layer on the lower surface of the splicing seam. The overlapping layer is a sandwich structure formed by coating cement slurry on the upper and lower surfaces of alkali-resistant glass fiber mesh cloth.
9. The composite floor slab according to claim 8, characterized in that: The width of the overlapping layer is 100mm to 300mm.
10. The composite floor slab according to claim 8, characterized in that: The prefabricated panels are selected from cement-based thermal insulation prefabricated panels.
11. A composite floor slab according to claim 10, characterized in that: The cement-based thermal insulation prefabricated panel comprises a thermal insulation structure layer, an upper surface reinforcement layer and a lower surface reinforcement layer. The thermal insulation structure layer is located between the upper surface reinforcement layer and the lower surface reinforcement layer, and the thermal insulation structure layer is fixedly connected to the upper surface reinforcement layer and the lower surface reinforcement layer.
12. A composite floor slab according to claim 11, characterized in that: The upper surface reinforcement layer and the lower surface reinforcement layer are formed by coating cement slurry on the alkali-resistant glass fiber mesh cloth; the thermal insulation structure layer is formed by mixing and flattening the cement-based thermal insulation slurry and vibrating it.
13. A composite floor slab according to claim 12, characterized in that: The cement-based thermal insulation slurry comprises the following components: cement dry material, functionalized coupling agent, hydroxypropyl methylcellulose, rubber powder, rice husk, and nano-silicon expanded resin particles; 2-3g of the functionalized coupling agent, 2-3g of hydroxypropyl methylcellulose, 15-30g of rubber powder, 60-80g of rice husk, and 20-40g of nano-silicon expanded resin particles are added to every kilogram of cement dry material; the functionalized coupling agent is selected from one of kH570 silane coupling agent and DL-411 aluminate coupling agent.
14. A composite floor slab according to claim 13, characterized in that: The nano-silicon expanded resin particles are prepared by the following method: Step 1: ingredients: 100 parts of styrene, 2-5 parts of nano silicon powder, 0.3-0.5 parts of benzoyl peroxide, 0.04-0.08 parts of tert-butyl perbenzoate, 0.05-0.1 parts of hydroxyethyl cellulose, 0.3-0.5 parts of tricalcium phosphate, 0.02 parts of sodium pyrophosphate, and 8 parts of pentane; In the second step, 115 to 125 parts of deionized water are added to the reactor, and styrene, nano silicon powder, benzoyl peroxide, tert-butyl perbenzoate, and sodium pyrophosphate are added to the reactor according to the component proportions determined in step one, and 40 to 60% of the hydroxyethyl cellulose and tricalcium phosphate proportions determined in the first step are added at the same time, and the temperature is raised to 85 to 95° C. for constant temperature polymerization. After reacting for 3 to 4 hours, 20 to 30% of the hydroxyethyl cellulose and tricalcium phosphate proportions determined in the first step are added to the reactor, and the constant temperature reaction is continued for 3 to 4 hours. Finally, 20 to 30% of the hydroxyethyl cellulose and tricalcium phosphate proportions determined in the first step and pentane are added to the reactor, the pressure in the reactor is controlled to be ≤1.0Mpa, the temperature is raised to 115 to 130° C., maintained for 3 to 4 hours, and the material is cooled to below 30 to 50° C. for discharge, and the material is dehydrated and dried to obtain nano silicon expanded resin particles.
15. The composite floor slab according to claim 14, characterized in that: In the second step, the material is dehydrated and dried and then stirred in a powder coating agent for 1 to 4 minutes to obtain nano-silicon expanded resin particles; the coating agent includes the following components in mass percentage: monoglyceride 9 to 11%, diglyceride 18 to 22%, and zinc stearate 68 to 72%.
16. The composite floor slab according to claim 14, characterized in that: The cement-based thermal insulation prefabricated board is prepared according to the following method: Applying cement slurry on the mesh cloth to form a lower surface reinforcement layer; then stirring the cement-based thermal insulation slurry evenly, spreading it flat on the lower surface reinforcement layer, vibrating, drying and forming it, and obtaining a thermal insulation structure layer; Finally, a mesh cloth is laid on the thermal insulation structure layer and cement slurry is coated on the mesh cloth and dried naturally to obtain a cement-based thermal insulation prefabricated board.
17. A composite floor slab according to claim 16, characterized in that: Thermal conductivity of cement-based thermal insulation prefabricated panels .