Hybrid FRP Rebar (Steel-Core Composite Rebar)
Hybrid FRP Rebars are engineered to combine the corrosion resistance of fiber-reinforced polymers with the ductile behavior of a steel core.
By integrating a protected steel core within a composite outer layer, this system provides a balanced mechanical response, offering improved deformation capacity compared to conventional FRP rebars while maintaining enhanced durability in aggressive environments.
Hybrid FRP rebars are particularly suitable for applications where controlled deformation, crack control, and corrosion resistance are required simultaneously.
Key Benefits
- Combination of steel ductility and FRP corrosion resistance.
- Controlled post-yield mechanical response
- Improved deformation capacity compared to FRP rebars
- Reduced corrosion risk compared to conventional steel reinforcement
- Suitable for aggressive and corrosive environments
Design Philosophy
Hybrid FRP reinforcement is intended to provide an intermediate solution between traditional steel reinforcement and fully non-metallic FRP systems, offering enhanced durability while maintaining familiar structural behavior.
Unlike conventional FRP rebars, Hybrid FRP rebars exhibit a multi-stage tensile behavior resulting from the interaction between the steel core and the composite outer layer. This behavior enables controlled deformation and improved energy absorption compared to linear-elastic FRP reinforcement.
Three-Stage Tensile Response
Stage 1 -Elastic Composite Response
At initial loading stages, the hybrid rebar behaves elastically, with both the steel core and composite shell contributing to load resistance.
Stage 2 – Yield-Controlled Behavior
As loading increases, the steel core reaches its yield point, allowing controlled deformation while the composite layer continues to provide confinement and load sharing.
Stage 3 – Ultimate Resistance
At higher strain levels, the composite reinforcement governs the ultimate tensile capacity, ensuring a gradual and predictable failure mechanism
Comparison with FRP Rebars
Compared to conventional FRP rebars, Hybrid FRP rebars offer enhanced deformation capacity and a more familiar mechanical response, while still providing improved corrosion resistance relative to steel reinforcement.
Engineering Note
Structural design using Hybrid FRP rebars should be performed in accordance with applicable project requirements and design guidelines, taking into account the combined behavior of steel and composite materials.
Mechanical Properties – Hybrid FRP Rebar
Hybrid Rebar Diameter (mm) | Steel Core Diameter (mm) | Approx. Weight (kg/m) | Tensile Strength (MPa) | Tensile Modulus (GPa) |
14 mm | 10 mm | 0.745 kg/m | 700 MPa | 130 GPa |
15 mm | 10 mm | 0.780 kg/m | 750 MPa | 120 GPa |
16 mm | 12 mm0 | 0.1015 kg/m | 600 MPa | 130 GPa |
17 mm | 12 mm | 0.1115 kg/m | 650 MPa | 120 GPa |
Note : Values shown are indicative laboratory results. Actual performance may vary depending on product configuration, project requirements, and installation condition
Bond Performance with Concrete
Hybrid FRP rebars demonstrate reliable bond performance with concrete due to their surface profile and composite outer layer. Laboratory testing indicates bond strength values exceeding 15 MPa under standard test conditions.
Durability and Alkaline Resistance
Hybrid FRP exhibit high resistance to alkaline environments commonly found in concrete.
Testing conducted in high-alkaline solutions ( pH > 13) at elevated temperatures indicates retention of more than 80% of mechanical performance after extended exposure periods.
Tested Performance
The above properties are based on laboratory tensile testing conducted in accordance with ASTM D7205on hybrid composite reinforcement specimens
Typical Applications
- Concrete structures exposed to aggressive or corrosive environment
- Infrastructure projects requiring improved durability and controlled deformation
- Marine and coastal structures
- Bridge decks and transportation infrastructure
- Industrial foundations and slabs
- Water and wastewater treatment facilities
- Structures where reduced corrosion risk compared to steel reinforcement is required
- and more
When Hybrid FRP is Preferred
HOVACO Hybrid FRP rebars are preferred in applications where the linear-elastic behavior of conventional FRP rebar is not desirable, and a more controlled deformation response is required.
By combining a steel core with a composite outer layer, Hybrid FRP reinforcement provides enhanced mechanical response while improving resistance to corrosion compared to traditional steel reinforcement.
Environmental Exposure Conditions
- High moisture environments
- Chloride-exposed structures
- Alkaline concrete environments
- Industrial and chemically aggressive conditions
Application Note
The selection and design HOVACO Hybrid FRP rebars should be based on project-specific requirements and applicable design guidelines, considering the combined behavior of steel and composite materials.
Available Sizes
Hybrid Rebar Diameter (mm) | Steel Core Diameter (mm) | Approx. Weight (kg/m) |
14 mm | 10 mm | 0.745 kg/m |
15 mm | 10 mm | 0.780 kg/m |
16 mm | 12 mm | 1.015 kg/m |
17 mm | 12 mm | 1.115 kg/m |
Note : Customized diameters and lengths can be manufactured upon request.
Cutting & On-Site Handling
HOVACO Hybrid FRP rebars can be easily cut on-site using commonly available construction cutting tools equipped.
Bending & Anchorage Solutions
Due to the composite structure of Hybrid FRP rebars, on-site bending is not recommended. HOVACO offers multiple practical solutions to accommodate bending and anchorage requirements in concrete structures.
Option 1 – Factory-Produced Bent Bars
Custom bent Hybrid FRP rebars can be manufactured at the factory based on approved project drawings, ensuring accurate detailing and controlled production.
Option 2 – Steel Bends with Overlap
Conventional steel bends can be used in combination with straight Hybrid FRP rebars, utilizing appropriate overlap lengths as specified by project design.
Option 3 -Anchorage Systems
Specialized anchorage systems and end-term solutions are available to ensure effective load transfer in demanding structural detailing conditions.
Installation Notes
- Hybrid FRP rebars should be handled and installed in accordance with project specifications.
- Proper alignment and placement should be ensured prior to concrete casting
- Installation practices should consider the combined behavior of steel and composite materials
Ordering & Technical Support
For pricing, technical documentation, and project-specific support, please contact HOVACO Global.