Author: Site Editor Publish Time: 2025-10-11 Origin: Site
Carbon fiber reinforced polymer (CFRP) is one of the most widely used high-performance reinforcement materials in civil engineering. With its advantages of high strength, lightweight, corrosion resistance, and ease of construction, it has become a core material for reinforcing and renovating concrete, steel, and masonry structures. Its application scenarios span the entire lifecycle of a building structure, from improving the performance of new structures to repairing and extending the life of existing structures, and even for emergency reinforcement after disasters. Specific applications can be categorized by structural type and reinforcement objective as follows:
The reinforcement function of carbon cloth essentially involves forming a "synergistic force-bearing system" with the original structure through the adhesive (epoxy resin). This transfers the carbon cloth's high strength (tensile strength approximately 7-10 times that of ordinary steel bars) to weak areas of the structure, thereby compensating for insufficient load-bearing capacity, rigidity deficiencies, or durability issues in the original structure.
Concrete structures are the core application for carbon cloth reinforcement, including key components such as beams, slabs, columns, walls, and joints. The core issues addressed are "inadequate bearing capacity," "crack control," and "ductility improvement." Specific applications are shown in the table below:
| Reinforced components | Core issues | Carbon cloth reinforcement methods | Typical scenarios |
| Concrete beams | Insufficient bending bearing capacity (excessive deflection, bottom cracking), insufficient shear bearing capacity (oblique cracks at beam ends) | - Bending reinforcement: 1-3 layers of carbon cloth are pasted on the bottom of the beam (parallel to the direction of force) - Shear reinforcement: U-shaped or ring-shaped carbon cloth is pasted on the side of the beam (perpendicular to the direction of force) | Renovation of floor beams of old office buildings (increased load), repair of bridge main beams (increased vehicle load) |
| Concrete columns | Insufficient axial/eccentric compressive bearing capacity (column cracking, deformation), insufficient ductility (brittle failure due to earthquakes) | - Hoop-wrapped carbon cloth (creating a "constraint effect", similar to stirrups) - Carbon cloth glued to the biaxial tension zone (resisting horizontal forces) | Seismic reinforcement of frame structure columns (improvement of seismic resistance of old buildings), load-increasing transformation of basement columns |
| Concrete slabs | Insufficient bending bearing capacity (cracks at the bottom of the plate, insufficient bearing capacity), insufficient local shear resistance | - Carbon cloth strips are pasted along the stress direction on the bottom of the board (unidirectional or bidirectional) - Radial carbon cloth is pasted on the board column nodes (to resist punching shear) | Adding partitions/equipment to residential floors (increased load), converting garage roofs to commercial use |
| Concrete walls | Insufficient shear bearing capacity (diagonal cracks in the wall) and insufficient out-of-plane bearing capacity | - Horizontal carbon cloth is pasted on the wall (to resist horizontal shear force) - Bidirectional carbon cloth mesh is pasted on the wall (to improve out-of-plane stiffness) | Seismic reinforcement of shear wall structures, anti-seepage and reinforcement of basement retaining walls |
| Joints | Insufficient bearing capacity of the core areas of beam-column joints and wall panel joints (earthquakes easily lead to damage) | - Paste the node area with a "tic-tac-toe" or ring-shaped carbon cloth (wrapping the core area) | Seismic retrofitting of frame structure nodes (old building nodes without stirrups or insufficient stirrups) |
Steel structure reinforcement requirements are often focused on increasing bearing capacity, improving stability, and repairing damage. Carbon cloth offers the advantages of eliminating the need for welding (preventing damage to the steel structure from high temperatures) and does not increase the structure's deadweight. Specific applications include:
Reinforcement of Tension/Compression Members: Carbon cloth is applied to the flanges or webs of steel structures to increase tensile/compressive bearing capacity (e.g., when steel columns or beams have insufficient cross-sections).
Joint Reinforcement: When welds crack or bolted connections are insufficient at steel joints, carbon cloth is applied around the joints to disperse stress concentrations (e.g., at steel truss joints and steel frame beam-column joints).
Fatigue Damage Repair: When fatigue cracks develop in steel structures subjected to alternating loads (e.g., bridges and factory crane beams), carbon cloth is applied to seal the cracks, preventing them from propagating and extending fatigue life.
Masonry structures (brick walls and columns) have high rigidity but very low tensile strength, making them susceptible to cracking due to temperature fluctuations, settlement, or earthquakes. Carbon cloth is primarily used for:
Wall Anti-Crack/Seismic Reinforcement: Attaching carbon cloth horizontally or vertically to the surface of brick walls increases the tensile and shear resistance of the wall and reduces cracking (e.g., brick walls of old residential buildings and historical buildings);
Brick Column Reinforcement: Wrapping axially compressed brick columns with carbon cloth circumferentially creates a constraint and increases compressive bearing capacity (e.g., brick columns of old factory buildings and fences).
Bridge Structures: Flexural reinforcement of main beams (using carbon cloth on the bottom), seismic reinforcement of bridge piers (using carbon cloth on the circumferential surface), and reinforcement of the lower slab of bridge deck pavement (using carbon cloth to improve crack resistance). The lightweight nature of carbon cloth avoids adding weight to the bridge.
Tunnel Structures: When cracks or leaks occur in the tunnel lining concrete, carbon cloth can be applied to the inside to seal the cracks and increase lining stiffness (e.g., subway tunnel and highway tunnel repairs).
Historical Buildings/Cultural Relics: Reinforcement of historical buildings (e.g., ancient wooden structures encased in concrete or masonry) requires minimally invasive treatment. Carbon cloth application does not require demolition of existing components and can be combined with antique coatings, minimizing the appearance of the building (e.g., reinforcement of beams and columns in ancient city walls and temples).
