What Is Fiber Reinforced Polymer?
Fiber Reinforced Polymer (FRP) is a composite material made of strong, stiff fibers embedded in a polymer matrix. The fibers provide strength and stiffness; the matrix binds the fibers together, transfers load between them, and protects them from environmental damage.
FRP is not a single material but a family of composites, classified by their reinforcing fiber type. The three main types used in structural engineering are CFRP (Carbon Fiber Reinforced Polymer), GFRP (Glass Fiber Reinforced Polymer), and AFRP (Aramid Fiber Reinforced Polymer). Each offers distinct advantages for different applications.
Three FRP Types Compared
CFRP — Carbon Fiber Reinforced Polymer
- Tensile strength: 2,400-4,900 MPa
- Elastic modulus: 160-390 GPa
- Density: 1.5-1.8 g/cm³
- Advantages: Highest strength and stiffness, lowest weight, excellent fatigue resistance, no corrosion
- Limitations: Highest cost, electrically conductive (can cause galvanic corrosion with aluminum), brittle failure mode
- Best for: Structural strengthening of buildings and bridges, seismic retrofit, aerospace
GFRP — Glass Fiber Reinforced Polymer
- Tensile strength: 1,000-2,400 MPa
- Elastic modulus: 35-72 GPa
- Density: 1.8-2.5 g/cm³
- Advantages: Lowest cost, electrically insulating, radar transparent, good impact resistance
- Limitations: Lower stiffness than CFRP (about one-third), heavier, susceptible to alkaline environments
- Best for: Non-structural reinforcement, rebar replacement, electrical applications, marine
AFRP — Aramid Fiber Reinforced Polymer
- Tensile strength: 2,000-3,600 MPa
- Elastic modulus: 60-125 GPa
- Density: 1.3-1.4 g/cm³
- Advantages: Excellent impact and abrasion resistance, lowest density, good vibration dampening
- Limitations: Poor compressive strength, degrades under UV, absorbs moisture
- Best for: Impact protection, ballistic applications, rope and cable, vibration-sensitive structures
FRP vs Traditional Materials
| Property | CFRP | GFRP | Steel | Concrete |
|---|---|---|---|---|
| Tensile strength (MPa) | 2,400-4,900 | 1,000-2,400 | 400-600 | 2-5 |
| Elastic modulus (GPa) | 160-390 | 35-72 | 200 | 25-35 |
| Density (g/cm³) | 1.5-1.8 | 1.8-2.5 | 7.85 | 2.4 |
| Corrosion | None | None | Significant | Carbonation |
| Fatigue | Excellent | Good | Moderate | Poor |
The combination of high strength, low weight, and corrosion immunity makes FRP composites increasingly attractive for infrastructure applications where lifecycle cost is considered alongside initial cost.
FRP Manufacturing Methods for Structural Products
Pultrusion: Continuous fibers are pulled through a resin bath and heated die to produce constant cross-section profiles (plates, strips, rods, I-beams). This is the primary method for producing CFRP plates used in structural strengthening. Wet lay-up: Dry fiber fabric is saturated with resin on-site and applied directly to the structure. This is the most common application method for CFRP structural strengthening in construction. Vacuum infusion: Dry fibers are placed in a mold, sealed under vacuum bag, and resin is drawn through the fiber stack by vacuum pressure. Produces higher-quality laminates than wet lay-up with better fiber-to-resin ratio. Filament winding: Continuous fibers are wound around a mandrel in precise patterns. Used for pipes, tanks, pressure vessels, and cylindrical components.FRP in Structural Strengthening
The structural strengthening market is dominated by CFRP because its high modulus (comparable to steel) makes it effective at controlling deflection and crack widths in strengthened concrete members. GFRP, despite its lower cost, requires 3-4 times more material area to achieve the same strengthening effect due to its lower modulus.
Our product range focuses on CFRP systems for structural strengthening, including fabrics from 200 to 600 g/m², pultruded plates, and all associated resin and adhesive systems. We supply these materials to structural strengthening projects worldwide across building, bridge, tunnel, wind energy, and industrial applications.
Explore our CFRP product range or contact us for technical consultation.