Flexural Pseudo-Ductility Effect in Hybrid GFRP/CFRP Bars under Static Loading Conditions

Area of Science:

• Civil Engineering
• Materials Science
• Polymer Science

Background:

• Composite rebars are prone to brittleness when overloaded, a significant challenge in civil engineering.
• The pseudo-ductility effect is a key area of research to enhance the performance of composite materials.

Purpose of the Study:

• To investigate methods for inducing pseudo-ductility in composite rebars.
• To compare the effectiveness of filament winding and hand braiding techniques in enhancing composite rebar properties.

Main Methods:

• Four-point bending tests were conducted on unidirectional (UD) rods with glass fiber-reinforced polymer (FRP) and carbon FRP cores.
• Overwrapping techniques included filament winding and hand braiding using carbon and glass roving or carbon fiber sleeves in an epoxy matrix.
• Microstructural analysis was performed using scanning electron microscopy (SEM) and computed tomography (CT).

Main Results:

• Both overwrapping techniques demonstrated the pseudo-ductility effect in composite rebars after reaching maximum force.
• Mechanical tests revealed distinct material behaviors influenced by the different overwrapping methods.
• Microstructural investigations identified structural differences correlating with observed mechanical performance.

Conclusions:

• The study successfully demonstrated pseudo-ductility in composite rebars using filament winding and hand braiding techniques.
• The choice of overwrapping technique significantly impacts the pseudo-ductility and mechanical behavior of composite rebars.
• Microstructural analysis provides insights into the performance variations between different composite rebar designs.