CN112482816A - FRP/ECC double-faced adhesive type reinforced concrete bidirectional plate for reinforcing damaged steel bar and preparation method thereof - Google Patents
FRP/ECC double-faced adhesive type reinforced concrete bidirectional plate for reinforcing damaged steel bar and preparation method thereof Download PDFInfo
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- CN112482816A CN112482816A CN202011410983.8A CN202011410983A CN112482816A CN 112482816 A CN112482816 A CN 112482816A CN 202011410983 A CN202011410983 A CN 202011410983A CN 112482816 A CN112482816 A CN 112482816A
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- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
- E04G23/00—Working measures on existing buildings
- E04G23/02—Repairing, e.g. filling cracks; Restoring; Altering; Enlarging
- E04G23/0218—Increasing or restoring the load-bearing capacity of building construction elements
Abstract
The invention discloses an FRP/ECC double-faced adhesive type reinforced concrete bidirectional plate and a preparation method thereof. According to the method, the transverse and longitudinal bonding strength between the FRP grid/ECC and the RC bidirectional plate is improved by coating the epoxy resin glue between the FRP grid/ECC and the RC bidirectional plate. For the RC plate with serious cracks on the surface or large cracks caused by unloading, the crack part after FRP grid/ECC reinforcement has larger stripping stress along the normal direction of the interface. Once the peeling stress is larger than the transverse and longitudinal bonding strength between the reinforcing layer and the RC beam, the reinforcing layer can peel off to cause reinforcing failure. When the bidirectional plate is reinforced, the FRP grids are stressed bidirectionally, and the requirement on bonding strength is higher. The epoxy resin glue can be soaked into new and old concrete to strengthen the interface and improve the bonding strength at the interface. Meanwhile, the FRP is restrained by spraying the ECC coating, so that the damage of harmful ions can be effectively resisted, and the problem of aging of the binder is solved.
Description
Technical Field
The invention relates to the field of concrete structure reinforcement, in particular to an FRP/ECC double-faced adhesive type reinforced damaged reinforced concrete bidirectional plate and a preparation method thereof.
Background
The reinforced concrete beam plate structure is one of the most common structural forms in civil engineering, but in the long-term use process, the reinforced concrete beam plate structure can be subjected to the natural disasters such as severe environment, earthquake, fire and the like, and the structure bearing load is continuously increased or the use function is changed. The large-amount reinforced concrete bidirectional plate structure has the problems of serious reinforcing steel bar corrosion, excessive cracks, overlarge fishing rate, insufficient bearing capacity and the like, and has durability, applicability and safety. From the development process of the European and American countries, the method adopting reinforcement and repair is occupying an increasingly large proportion. Therefore, the color fading of the 'great civil engineering' era in China can be expected, various effective reinforcing and reforming measures are researched, the bearing capacity of the damaged reinforced concrete beam plate structure is recovered and improved, the reinforced concrete beam plate structure is suitable for higher bearing requirements, and the requirement of new use functions is very important.
At present, commonly used reinforcing and modifying methods include a crack repairing method, a steel bonding reinforcing method, an external bonding FRP reinforcing method and the like. The externally bonded FRP reinforced concrete structure has the outstanding advantages of light weight, high strength, strong designability, light dead weight, convenient construction, small influence on the appearance of the structure, good corrosion resistance and the like. For the traditional external adhesion FRP reinforcement technology, the adhesion between the FRP sheet or plate and the reinforced structure concrete surface mainly depends on an adhesive, and the adhesive is a high molecular polymer made of epoxy resin as a matrix. The organic adhesive is very sensitive to damp-heat, dry-wet cycle, salt fog, high temperature and other environments. Because the concrete structure needing to be reinforced is in a severe environment, the bonding strength of the FRP reinforcing system is seriously degraded in a severe service environment. Once the FRP reinforcement system and the existing concrete are bonded to fail, the reinforcement effect is lost, and the existing structure is in a more dangerous state. Therefore, it is necessary to properly solve the problem of durability due to the deterioration of the adhesive at the interface between the FRP and the reinforced concrete.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a preparation method of an FRP/ECC double-faced adhesive type reinforced concrete bidirectional plate.
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
in a first aspect, the invention provides an FRP/ECC double-faced adhesive reinforced concrete bidirectional slab, which is characterized in that: the reinforced composite plate comprises a reinforced bidirectional plate, a bonding agent, a composite material and an FRP grid; the preparation method comprises the following steps:
cracks exist on the tension side of the reinforced bidirectional plate, adhesive is coated on the tension side of the reinforced bidirectional plate before reinforcement,
fixing the FRP grids to the tension side, and finally spraying a composite material on the tension side to form a reinforced whole, thereby obtaining the FRP/ECC double-faced adhesive reinforced damaged reinforced concrete bidirectional plate;
the FRP grids are wrapped and restrained by the composite material; the adhesive is coated between the FRP grid/ECC and the reinforced bidirectional plate, so that the transverse and longitudinal adhesive strength between the FRP grid/ECC and the reinforced bidirectional plate is improved, and the reinforcing failure caused by the peeling and falling phenomena of the reinforcing layer due to overlarge peeling stress is prevented; the adhesive can be soaked into concrete to strengthen the interface and improve the adhesive strength at the interface.
In a second aspect, the invention provides a method for preparing the FRP/ECC double-faced adhesive reinforced damaged reinforced concrete bidirectional slab, which is characterized in that: the method improves the transverse and longitudinal bonding strength between the FRP grid/ECC and the existing concrete slab by smearing the bonding agent between the FRP grid/ECC and the existing concrete slab; the adhesive can be soaked into concrete to strengthen the interface and improve the adhesive strength at the interface; the method comprises the following steps:
1) before reinforcing, coating an adhesive on the tension side of the reinforced bidirectional plate;
2) fixing the FRP grids to the tension side;
3) and finally, spraying the composite material on the tension side to form a reinforced whole.
As a preferred scheme, the composite material is an ultrahigh-toughness cement-based composite material, and the weight ratio of each component to cement is 1.4-2.0 of fly ash; 1.0-1.1 parts of 80-120-mesh quartz sand; 0.5-1 part of water; water reducing agent: 0.01-0.015; PVA: 0.05-0.06.
Further, the FRP mesh is a CFRP mesh.
Further, the adhesive is an epoxy glue.
When the bidirectional plate is reinforced, the FRP grids are stressed bidirectionally. To ensure that the FRP provides effective bi-directional restraint, the bond strength at the interface needs to be increased. The adhesive can be soaked into concrete to strengthen the interface and improve the adhesive strength at the interface. The method thus simultaneously increases the bond strength between the FRP mesh/ECC and the existing concrete panel in both the transverse and longitudinal directions by applying the adhesive between the FRP mesh/ECC and the existing concrete panel. The reinforcing failure caused by peeling and falling off phenomena of the reinforcing layer due to overlarge peeling stress is prevented.
The working principle of the invention is as follows:
the epoxy resin glue can be infiltrated into new and old concrete, and forms giant molecules with a three-dimensional network structure under the action of a curing agent, so that the bonding at the interface is strengthened. Although epoxy adhesives provide reliable bonding, such organic adhesives are very sensitive to hot and humid environments, dry and wet cycles, salt spray, high temperatures, etc., resulting in poor durability. The characteristics of high temperature resistance and small cracks of the ultra-high toughness cement-based composite material can increase the fire resistance of the structure and the erosion resistance of harmful ions such as chloride ions and the like; in addition, the ultimate tensile strain can exceed 3%, and the FRP grid is wrapped and restrained by taking the FRP grid as an interface adhesive and a reinforcing material, so that the problem that the FRP is easy to peel off due to aging of the interface adhesive of the externally-adhered FRP sheet is solved. So that one side of the FRP grid is coated with epoxy resin glue to be fixed on the bidirectional plate
The side is pulled and coated with ECC to wrap the side, so that the durability of the epoxy resin adhesive can be improved, the cooperative work with the FRP material can be ensured, the mechanical properties of the two materials are fully exerted, and multiple effects of improving the stress performance, the durability and the fire resistance are realized.
The invention has the advantages and beneficial effects that:
when the bidirectional plate is reinforced, the FRP grids are stressed in both directions, so that the requirement on bonding strength is higher. According to the invention, the epoxy resin glue is coated between the FRP grid/ECC and the existing concrete slab, so that the transverse and longitudinal bonding strength between the FRP grid/ECC and the existing concrete slab is improved. The FRP grid replaces an FPX sheet, so that the problem that the ultrahigh-toughness cement-based composite material cannot completely permeate the FRP sheet and generate enough interface bonding strength is solved; one side of the FRP grid is coated with epoxy resin glue and fixed on the tension side of the bidirectional plate, and then is coated with ECC, so that the high-temperature resistance and small crack of the ECC material can be exerted, the fire resistance of the structure and the corrosion resistance of harmful ions such as chloride ions can be increased, the durability of the epoxy resin glue is improved, the excellent tensile property of the epoxy resin glue can ensure the cooperative work with the FRP material, the mechanical properties of the two materials are fully exerted, and the multiple effects of improving the stress performance, the durability and the fire resistance are realized.
Drawings
FIG. 1 is a schematic view of a FRP/ECC double-faced adhesive reinforced concrete two-way slab for reinforcing damaged reinforced concrete;
FIG. 2 is a schematic view of a bi-directional plate bottom crack;
FIG. 3 is a schematic cross-sectional view of a FRP/ECC double-faced adhesive reinforced concrete bidirectional panel;
in the figure: 1. reinforced plate, 2, epoxy glue, 3, CFRP grid, 4, ECC, 5, crack.
Detailed Description
The invention is explained in further detail below with reference to the figures and the specific embodiments.
As shown in figure 1, the invention relates to a method for reinforcing a reinforced concrete bidirectional plate by using FRP grid/ECC double-sided adhesive. The concrete used for casting the slab is C20 concrete with the size of 1800mm multiplied by 1500mm multiplied by 70mm and four simple sides. Before reinforcement, firstly, a bonding agent 2 is coated on the tension side, then the FRP grid 3 is fixed on the side, and finally, a composite material 4 is sprayed to form a reinforced whole.
The composite material 4 is an ultrahigh-toughness cement-based composite material, and the weight ratio of each component to the cement is 1.4-2.0 of fly ash; 1.0-1.1 parts of 80-120-mesh quartz sand; 0.5-1 part of water; water reducing agent: 0.01-0.015; PVA: 0.05-0.06; the FRP grid 3 is a CFRP grid; the binder 2 is epoxy resin glue.
Panel 1(B1) is an unreinforced panel and panel 2(B2) is a reinforced panel.
| Board | Yield load KN | Ultimate load KN |
| |
20 | 44 |
| |
24 | 54 |
The FRP grid/ECC is adopted to reinforce the bidirectional plate, and the bearing capacity is improved by 10-15%. The method for reinforcing the reinforced concrete bidirectional plate by adopting the FRP grid/ECC double-faced adhesive tape has the advantage that the bearing capacity is improved by 20-30%.
During the construction process, the control of the key links is required, and the control is divided into two aspects of materials and construction. Firstly, in terms of materials, the thickness of an FRP grid and the size of the grid size are selected according to actual needs; the preparation of the ultra-high toughness cement-based composite material is carried out according to the proportion and the feeding sequence strictly, so that the ultra-high toughness cement-based composite material is ensured to be reliably bonded with concrete and can be coordinated with the original concrete bidirectional plate for deformation. Secondly, in the construction link, before the FRP grids are fixed to the tension side of the bidirectional plate by epoxy resin glue, the concrete interface is processed as required, and then the FRP grids are fixed to the concrete surface, so that gaps are avoided; the required overlapping length is required to be met during overlapping, both ends of the overlapping section are fixed firmly by using an anchor, and the overlapping part is prevented from becoming a weak part. In the case of the injection work, voids are generated in some crossing portions where the crossing portions are difficult to be filled, and voids in the mesh portions are filled and compacted with trowels.
Claims (6)
1. The utility model provides a two-way board of impaired reinforced concrete is consolidated to FRP ECC double faced adhesive tape formula which characterized in that: comprises a reinforced bidirectional plate (1), an adhesive (2), a composite material (4) and an FRP grid (3); the preparation method comprises the following steps:
the method comprises the steps that a crack (5) exists on the tension side of a reinforced bidirectional plate (1), before reinforcement, an adhesive (2) is coated on the tension side of the reinforced bidirectional plate (1), an FRP grid (3) is fixed to the tension side, and finally a composite material (4) is sprayed on the tension side to form a reinforced whole, so that the FRP/ECC double-faced adhesive reinforced damaged reinforced concrete bidirectional plate is obtained;
the FRP grid (3) is wrapped and restrained by the composite material (4); the adhesive (2) is coated between the FRP grid/ECC and the reinforced bidirectional plate (1) so as to improve the transverse and longitudinal adhesive strength between the FRP grid/ECC and the reinforced bidirectional plate (1) and prevent the reinforcing layer from peeling off due to overlarge peeling stress to cause reinforcing failure; the binder (2) can be soaked into concrete to strengthen an interface and improve the binding strength at the interface.
2. The preparation method for preparing the FRP/ECC double-faced adhesive type reinforced damaged reinforced concrete bidirectional plate as recited in claim 1, is characterized in that: the method improves the transverse and longitudinal bonding strength between the FRP grid/ECC and the existing concrete slab by smearing the bonding agent between the FRP grid/ECC and the existing concrete slab; the adhesive can be soaked into concrete to strengthen the interface and improve the adhesive strength at the interface; the method comprises the following steps:
1) before reinforcement, coating an adhesive (2) on the tension side of a reinforced bidirectional plate (1);
2) fixing the FRP grid (3) to the tension side;
3) and finally, spraying the composite material (4) on the tension side to form a reinforced whole.
3. The preparation method of the FRP/ECC double-faced adhesive type reinforced concrete bidirectional plate as claimed in claim 2, which is characterized in that: the composite material (4) is an ultrahigh-toughness cement-based composite material, and the weight ratio of each component to cement is 1.4-2.0 of fly ash; 1.0-1.1 parts of 80-120-mesh quartz sand; 0.5-1 part of water; water reducing agent: 0.01-0.015; PVA: 0.05-0.06.
4. The preparation method of the FRP/ECC double-faced adhesive type reinforced concrete bidirectional plate reinforced by damaged steel bars according to claim 2 or 3, which is characterized by comprising the following steps: the FRP grid (3) is a CFRP grid.
5. The preparation method of the FRP/ECC double-faced adhesive type reinforced concrete bidirectional plate reinforced by damaged steel bars according to claim 2 or 3, which is characterized by comprising the following steps: the binder (2) is epoxy resin glue.
6. The preparation method of the FRP/ECC double-faced adhesive type reinforced concrete bidirectional plate according to claim 4, which is characterized in that: the binder (2) is epoxy resin glue.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011410983.8A CN112482816A (en) | 2020-12-03 | 2020-12-03 | FRP/ECC double-faced adhesive type reinforced concrete bidirectional plate for reinforcing damaged steel bar and preparation method thereof |
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|---|---|---|---|
| CN202011410983.8A CN112482816A (en) | 2020-12-03 | 2020-12-03 | FRP/ECC double-faced adhesive type reinforced concrete bidirectional plate for reinforcing damaged steel bar and preparation method thereof |
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Citations (7)
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|---|---|---|---|---|
| KR20100115646A (en) * | 2009-04-20 | 2010-10-28 | (주)안풍건설 | Repairing method of concrete structure using fibersheet and pushpin |
| CN103496865A (en) * | 2013-09-16 | 2014-01-08 | 北京工业大学 | Hybrid FRP (Fiber Reinforced Plastic) grid enhancedreinforced ECC (Engineered Cementitious Composite) and application thereof tostructure for reinforcing concrete structure |
| CN105888283A (en) * | 2016-05-10 | 2016-08-24 | 郑州大学 | Method for reinforcing reinforced concrete shear wall structure by using FRP grid strengthened ECC strips |
| CN205591398U (en) * | 2016-05-10 | 2016-09-21 | 郑州大学 | FRP mesh grid - ECC strip reinforcing reinforced concrete shear wall |
| CN105948579A (en) * | 2016-04-27 | 2016-09-21 | 山东大学 | Waterproof ECC and carbon fiber cloth composite reinforced material and use method thereof |
| KR20160120114A (en) * | 2015-04-07 | 2016-10-17 | 한국기술교육대학교 산학협력단 | Fiber Reinforced Concrete Structure With End Slip Prevention |
| CN107382187A (en) * | 2017-06-26 | 2017-11-24 | 山东建筑大学 | Reinforcement of concrete post method based on Green High Performance fiber reinforced cement-based composite material |
-
2020
- 2020-12-03 CN CN202011410983.8A patent/CN112482816A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20100115646A (en) * | 2009-04-20 | 2010-10-28 | (주)안풍건설 | Repairing method of concrete structure using fibersheet and pushpin |
| CN103496865A (en) * | 2013-09-16 | 2014-01-08 | 北京工业大学 | Hybrid FRP (Fiber Reinforced Plastic) grid enhancedreinforced ECC (Engineered Cementitious Composite) and application thereof tostructure for reinforcing concrete structure |
| KR20160120114A (en) * | 2015-04-07 | 2016-10-17 | 한국기술교육대학교 산학협력단 | Fiber Reinforced Concrete Structure With End Slip Prevention |
| CN105948579A (en) * | 2016-04-27 | 2016-09-21 | 山东大学 | Waterproof ECC and carbon fiber cloth composite reinforced material and use method thereof |
| CN105888283A (en) * | 2016-05-10 | 2016-08-24 | 郑州大学 | Method for reinforcing reinforced concrete shear wall structure by using FRP grid strengthened ECC strips |
| CN205591398U (en) * | 2016-05-10 | 2016-09-21 | 郑州大学 | FRP mesh grid - ECC strip reinforcing reinforced concrete shear wall |
| CN107382187A (en) * | 2017-06-26 | 2017-11-24 | 山东建筑大学 | Reinforcement of concrete post method based on Green High Performance fiber reinforced cement-based composite material |
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Application publication date: 20210312 |