Concrete pavement slab repairing method

Abstract

The invention discloses a concrete pavement slab repairing method, and relates to the technical field of pavement slab repairing. The method comprises the following steps: performing interface pretreatment on a concrete pavement slab to be repaired; a composite reinforcing layer is laid on the concrete pavement slab subjected to interface pretreatment; and the composite reinforcing layer is maintained, and repairing of the concrete pavement slab is completed. The FRP grid and the ECC high-ductility concrete are compounded, the performance of the reinforcing layer is improved, the good effect on repairing the pavement slab is achieved, meanwhile, the cost is reduced, and the sustainable development target is met.

Description

Technical Field

[0001] This invention relates to a method for repairing concrete pavement panels, belonging to the field of pavement panel repair technology, and is particularly applicable to the repair of prefabricated concrete pavement panels in airports, highways, and other similar applications. Background Technology

[0002] Currently, airport pavements are mainly made of cast-in-place cement concrete, which is prone to cracking and other damage under repeated aircraft loads and environmental stresses. Airport pavement repairs significantly impact airport operations. Prefabricated pavements use factory-prefabricated pavement panels, which are then assembled on-site, allowing for faster maintenance. However, under the combined effects of loads and the environment, pavement panels can still suffer damage. Therefore, finding efficient ways to repair prefabricated pavement panels is of significant practical importance. Summary of the Invention

[0003] The purpose of this invention is to provide a method for repairing concrete pavement panels. By combining fiber-reinforced polymer (FRP) mesh and ECC high-ductility cement-based composite material, the performance of the reinforcement layer is improved, which has a significant effect on the repair of pavement panels.

[0004] To achieve the above objectives, the present invention employs the following technical solution, including:

[0005] Interface pretreatment is performed on the concrete pavement slab to be repaired;

[0006] A composite reinforcement layer is laid on the concrete pavement slab after interface pretreatment;

[0007] The composite reinforcement layer is cured to complete the repair of the concrete pavement slab.

[0008] Optionally, the interface pretreatment includes: roughening the interface of the concrete pavement to be repaired until the coarse aggregate is exposed, cleaning the surface and keeping it moist but without standing water, and applying an interface agent.

[0009] The interface agent is an epoxy-based interface agent.

[0010] Optionally, the composite reinforcement layer includes: an FRP mesh and ECC high-ductility concrete; the FRP mesh is a basalt fiber mesh and is cut according to the internal steel reinforcement dimensions of the concrete pavement slab.

[0011] Optionally, the preparation of the ECC high-ductility concrete includes:

[0012] Cement, fly ash, sand, and admixtures are added to a mixer and mixed evenly at the first set speed. Water is then added to form a uniform slurry.

[0013] Continue stirring at the initial set speed, and sprinkle the fiber in batches;

[0014] Stir at a first set speed and a second set speed greater than the first set speed alternately until the fibers are completely dispersed and agglomerated.

[0015] Optionally, the fiber is PVA fiber with a volume content of 1.5%;

[0016] The ratio of cement to fly ash is 7:3;

[0017] The sand is quartz sand with a particle size of 110 mesh, a water-cement ratio of 0.28, and a sand-cement ratio of 0.36.

[0018] Optionally, the additives include thickeners and water-reducing agents;

[0019] The thickener used is hydroxypropyl methylcellulose, at a dosage of 0.03%.

[0020] The water-reducing agent is Sika water-reducing agent 540P, and the dosage is 0.25%.

[0021] The addition of water-reducing agents can indirectly reduce cement usage, lowering costs while improving the mechanical properties of concrete. Thickeners, by absorbing moisture and forming a network structure, increase the viscosity of the paste, allowing fibers to be evenly dispersed in the paste and ensuring that the material's toughness and strength meet the standards.

[0022] Optionally, the method for laying the composite reinforcement layer includes: first pouring a set amount of ECC high-ductility concrete on the interface of the concrete pavement slab after the interface pretreatment is completed, then placing the FRP mesh at the center of the interface of the concrete pavement slab, and then pouring the remaining ECC high-ductility concrete.

[0023] Optionally, the ECC high-ductility concrete is poured to a thickness of 15mm-20mm within 30 minutes of completion. This must be done in conjunction with surface repair of the pavement slab, ensuring the reinforced slab thickness remains consistent with the original slab.

[0024] Optionally, the curing of the composite reinforcement layer includes: after the ECC high ductility concrete is poured, smoothing the surface and covering the surface of the composite reinforcement layer with a damp cloth, and steam curing for at least 2 days.

[0025] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0026] This invention effectively strengthens and repairs concrete pavement slabs by combining fiber-reinforced polymer (FRP) meshes with high-ductility ECC (ecologically modified cementitious) composite materials. The FRP mesh provides high load-bearing capacity, while the ECC material offers ductility and crack control; together, they significantly improve the durability and fatigue resistance of the repaired structure. Modular repair reduces material waste, and the use of ECC materials from industrial waste (such as fly ash) aligns with sustainable development goals. In practical construction, prefabricated FRP meshes and factory-prefabricated ECC materials can significantly shorten the construction cycle and meet the demands of rapid airport reopening. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the composite reinforcement layer provided in an embodiment of the present invention;

[0028] Figure 2 A cross-sectional view of a prefabricated concrete pavement panel provided in an embodiment of the present invention;

[0029] Figure 3 A schematic diagram of a scaled-down model of a prefabricated concrete pavement panel provided in an embodiment of the present invention;

[0030] Figure 4 A comparison diagram of the load strength of the control plate and the repair plate provided in the embodiments of the present invention;

[0031] Figure 5 A physical image of the comparison plate provided in the embodiments of the present invention;

[0032] Figure 6 A physical image of the repair plate provided in an embodiment of the present invention.

[0033] Figure label:

[0034] 1. FRP mesh; 2. ECC high ductility concrete; 3. Reinforcing steel; 3.1. First layer of reinforcing steel; 3.2. Second layer of reinforcing steel; 4. Interface; 5. Surface defects. Detailed Implementation

[0035] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations thereof. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0036] The term "and / or" simply describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Additionally, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0037] Example 1

[0038] This embodiment describes a method for repairing prefabricated concrete pavement panels, including:

[0039] Interface 4 pretreatment is performed on the prefabricated concrete pavement panels to be repaired.

[0040] A composite reinforcement layer is laid on the prefabricated concrete pavement slab after interface pretreatment.

[0041] The composite reinforcement layer is cured to complete the repair of the prefabricated concrete pavement slab.

[0042] The specific steps for performing the above method are as follows:

[0043] like Figure 2 The figure shown is a cross-sectional view of the prefabricated concrete pavement panel provided in this embodiment. First, the prefabricated concrete pavement panel is roughened at interface 4. The pavement panel is roughened until the coarse aggregate is exposed. The surface is cleaned and kept moist but without standing water. An interface agent is applied to enhance the adhesion between the new and old materials. Templates are set up around the perimeter to facilitate subsequent concrete pouring.

[0044] The interface agent used is epoxy-based interface agent CB-720, comprising component A and component B. Component A is epoxy resin, and component B is a modified amine curing agent. When using, component A and component B are mixed evenly in a 3:1 ratio and applied at a rate of 0.2-0.3 kg per square meter. Based on the chemical crosslinking characteristics of epoxy resin, a high-strength transition layer is formed, significantly improving the interfacial shear and tensile properties.

[0045] like Figure 1 The composite reinforcement layer provided in this embodiment includes: FRP mesh 1 and ECC high ductility concrete 2; the FRP mesh 1 is a basalt fiber mesh and is cut according to the size of the internal steel reinforcement 3 of the concrete pavement slab.

[0046] ECC high ductility concrete 2 is prepared using a mixer. First, dry materials such as cement, fly ash, sand, and admixtures are added and slowly mixed evenly. Then, water is added to form a uniform slurry. The mixer is kept running at a slow speed, and fibers are sprinkled into the slurry in batches. After all the fibers are added, the mixer speed is alternated between fast and slow until all the fibers are dispersed and agglomerated. The variable speed mixing time is 5 minutes, and generally, the maximum variable speed mixing time is 6 minutes.

[0047] The ECC high-ductility concrete 2 contains PVA fiber with a volume content of 1.5%, which has a compressive strength greater than 40 MPa, a tensile strength greater than 5 MPa, and an ultimate tensile strain greater than 3%. The ratio of cement to fly ash is 7:3; the sand is quartz sand with a particle size of 110 mesh, a water-cement ratio of 0.28, and a sand-cement ratio of 0.36.

[0048] The admixtures include a thickener and a water-reducing agent. The thickener is hydroxypropyl methylcellulose, used at a dosage of 0.03%; the water-reducing agent is Sika Water-Reducing Agent 540P, used at a dosage of 0.25%. A planetary mixer is used, alternating between fast and slow mixing to improve fiber dispersion. The addition of the water-reducing agent indirectly reduces cement usage, lowering costs while improving the mechanical properties of the concrete. The thickener, by absorbing water and forming a network structure, increases the viscosity of the paste, allowing the fibers to be evenly dispersed in the paste, ensuring the material meets toughness and strength standards.

[0049] The FRP mesh 1 is laid and the ECC high-ductility concrete 2 is poured. The FRP mesh 1 is cut according to the dimensions of the internal reinforcing steel 3 of the prefabricated concrete pavement panel. The FRP mesh 1 is a basalt fiber mesh with a thickness of at least 5 mm. The ECC high-ductility concrete 2 is poured in two layers according to the quantity. The prepared ECC high-ductility concrete 2 must be poured within 30 minutes. After the first pour is completed, the FRP mesh 1 is laid at the center of the pavement panel interface 4.

[0050] Among them, the pouring thickness of ECC high ductility concrete 2 is 15mm-20mm, which needs to be combined with the repair of surface defects 5 of the pavement panel, and the thickness of the reinforced panel should be consistent with that of the original panel.

[0051] The composite reinforcement layer is cured by: after the ECC high ductility concrete 2 is poured, smooth the surface and cover the surface of the composite reinforcement layer with a damp cloth, and steam curing for at least 2 days.

[0052] Example 2

[0053] This embodiment, based on the technical solution of Embodiment 1, conducted a scaled-down model test of prefabricated concrete pavement slab repair. The concrete compressive strength of the scaled-down pavement slab model used in the laboratory was approximately 55 MPa. The slab dimensions were l×h×b = 1500mm×750mm×120mm. The reinforcing bars were 8mm in diameter, HRB400, and arranged in a double-layer, bidirectional configuration with a spacing of 90mm. The upper and lower protective layers were 15mm thick. Detailed drawings of the pavement slab and reinforcement are shown below. Figure 3 As shown, (a) is a top view of the scaled model of the prefabricated concrete pavement panel, (b) is a front view of the scaled model of the prefabricated concrete pavement panel, and (c) is a side view of the scaled model of the prefabricated concrete pavement panel; in (b), the double-layer reinforcement includes the first layer of reinforcement 3.1 and the second layer of reinforcement 3.2.

[0054] The concrete pavement slabs used for repair need to be roughened: the concrete protective layer on the bottom surface of the slab is removed to expose the internal reinforcing steel bars 3. The base material of the repair layer is ECC high-ductility concrete 2 with a thickness of 25mm. FRP mesh 1 of the same size as the internal reinforcing steel bars 3 is set in the ECC high-ductility concrete 2, with a mesh thickness of 5mm and a specification of 100mm×100mm.

[0055] The static loading was performed using a simply supported long side (i.e., a span of 1500 mm), with the loading point located at the mid-span. The test used a 50t jack with three-point staged loading, each stage carrying 2 kN.

[0056] The test results are as follows Figure 4 As shown; Figure 5 This is a picture of the actual product for comparison. Figure 6 This is a picture of the actual board being repaired.

[0057] (1) The ultimate load of the control plate (unreinforced plate) is about 110kN, while that of the repaired plate is about 175kN, an increase of about 59%, and the enhancement effect is significant.

[0058] (2) The cracks in the control plate were wide and developed rapidly after cracking, while the cracks in the repair plate were mostly fine and dense, and the crack width increased slowly, indicating that the damage development of the ECC+FRP structure was well controlled.

[0059] Based on the above embodiments, this invention, through the combination of fiber-reinforced polymer (FRP) mesh and high-ductility cement-based composite material (ECC), achieves excellent results in the reinforcement and repair of prefabricated concrete pavement slabs. The repaired pavement slabs exhibit high strength and tensile strength. Furthermore, modular repair reduces material waste, and the use of ECC material from industrial waste aligns with sustainable development goals. In practical construction, the use of prefabricated FRP mesh and factory-prefabricated ECC material can significantly shorten the construction cycle and meet the requirements for rapid airport operation.

[0060] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method of repairing a concrete pavement panel, comprising: The application relates to a method for repairing a concrete pavement, which comprises the following steps: carrying out interface pretreatment on a concrete pavement to be repaired; laying a composite reinforcing layer on the concrete pavement after the interface pretreatment is completed; carrying out maintenance on the composite reinforcing layer to complete the repair of the concrete pavement.

2. The method of repairing a concrete pavement panel according to claim 1, wherein, The interface pretreatment comprises the following steps: carrying out interface (4) chiseling treatment on the concrete pavement to be repaired until coarse aggregates are exposed, cleaning the surface and keeping the surface moist and free of water, and brushing interface agent. The interface agent is an epoxy-based interface agent.

3. The method of claim 1, wherein the step of applying the repair material is performed by a robotic device. The composite reinforcing layer comprises an FRP grid (1) and ECC high-ductility concrete (2); the FRP grid (1) is a basalt fiber grid, and is cut according to the size of the internal steel bars (3) of the concrete pavement.

4. The method of claim 3, wherein the step of applying the repair material is performed by a robotic arm. The preparation of the ECC high-ductility concrete (2) comprises the following steps: cement, fly ash, sand and an additive are put into a mixer, water is added after uniform stirring at a first set speed, and a uniform slurry is formed; the first set speed is kept, and the fibers are added in batches; the fibers are alternately stirred at the first set speed and a second set speed greater than the first set speed until the fibers are completely dispersed and aggregated.

5. The method of claim 4, wherein the step of applying the repair material is performed by a robotic device. The fibers are PVA fibers, and the volume content is 1.5%; the cement and fly ash are in a ratio of 7:3; the sand is quartz sand, the particle size is 110 mesh, the water-binder ratio is 0.28, and the sand-binder ratio is 0.

36.

6. The method of claim 5, wherein the step of applying the repair material is performed by a robotic device. The additive comprises a thickening agent and a water-reducing agent; the thickening agent is hydroxypropyl methyl cellulose, and the dosage is 0.03%; the water-reducing agent is Sika water-reducing agent 540P, and the dosage is 0.25%.

7. The method of repairing a concrete pavement panel according to claim 3, wherein The method for laying the composite reinforcing layer comprises the following steps: pouring a set amount of ECC high-ductility concrete (2) on the interface (4) of the concrete pavement after the interface pretreatment is completed, placing the FRP grid (1) at the center position of the interface (4) of the concrete pavement, and then pouring the remaining ECC high-ductility concrete (2).

8. The method of claim 7, wherein the step of applying the repair material is performed by a robotic arm. The pouring thickness of the ECC high-ductility concrete (2) is 15mm-20mm, and the pouring time is within 30 minutes after the preparation is completed.

9. The method of repairing a concrete pavement panel according to claim 1, wherein, The maintenance on the composite reinforcing layer comprises the following steps: after the pouring of the ECC high-ductility concrete (2) is completed, the surface is smoothed, a wet cloth is covered on the surface of the composite reinforcing layer, and steam curing is carried out for at least 2 days.

Images