Activated Ductile CFRP NSMR Strengthening

Area of Science:

• Civil Engineering
• Materials Science

Background:

• Adhesively-bonded carbon fiber-reinforced polymer (CFRP) systems significantly strengthen concrete structures.
• Brittle concrete delamination failure, reduced warning, and inefficient CFRP use are challenges with current methods.

Purpose of the Study:

• To introduce and evaluate a novel ductile near-surface mounted reinforcement (NSMR) CFRP system.
• To investigate the use of ductile enclosure wedge (EW) end anchors and low E-modulus adhesive for enhanced ductility and CFRP utilization.

Main Methods:

• Five concrete T-beams were strengthened with the novel NSMR CFRP system.
• CFRP rod activation stress was approximately 980 MPa.
• Beam responses were compared to un-strengthened and conventional epoxy-bonded NSMR strengthened beams.

Main Results:

• The novel system demonstrated identical linear elastic response compared to epoxy-bonded NSMR.
• Average deflection and yielding regimes improved by 220% and 300%, respectively.
• Brittle failure modes were prevented, with failure initiated by concrete compression or anchor overload.

Conclusions:

• The novel ductile NSMR CFRP system provides significant strengthening and ductility control.
• Reproducible and predictable strengthening effects were achieved, correlating well with theoretical predictions.
• This system offers a promising solution for enhancing concrete structure performance and CFRP utilization.