Strengthening effect of prestressed near-surface mounted CFRP bar system according to material properties of aged reinforced concrete beams

The flexural performance improvement of age-deteriorated reinforced concrete (RC) beams by a near-surface mounted carbon fiber-reinforced polymer (NSM CFRP) bar system was experimentally investigated. Ten 6.4 m long RC beams were fabricated and tested in four-point bending using different concrete compressive strengths to distinguish between old and new concrete, different steel reinforcement ratios to reflect deterioration with age, and different quantities of prestressed and non-prestressed CFRP bars. The results indicated that the ultimate strengths of the NSM CFRP-strengthened RC beams were up to twice that of the un-strengthened control beam, and the strengthening effect increased with the material properties of the RC beam. A finite element model of the strengthened RC beam was constructed and verified against the experimental results, then used to conduct a parametric study of the influence of the concrete compressive strength and steel reinforcement ratio on the strengthening effect of the prestressed NSM CFRP bar system.

Automated summary

The experimental investigation found that the near-surface mounted carbon fiber-reinforced polymer (NSM CFRP) bar system can significantly improve the flexural performance of age-deteriorated reinforced concrete (RC) beams, with ultimate strengths up to twice that of the un-strengthened beams. The strengthening effect is closely related to the material properties of the RC beams.