Development of New Repair and Maintenance Technique with Carbon Fiber Reinforced Polymer Composite
T. Ando, E. Sawada, and K. Nii
Appears on pages(s):
carbon fiber; concrete sturctures; corrosion durability; impermeability; reinforcing bar
New repair and maintenance technique for existing reinforced concrete structures has been developed as a result of a marriage of corrosion prevention and carbon fiber reinforced polymer (CFRP) installation techniques. Rebar corrosion prevention is basically provided by penetrating liquid and/or mortar, while mechanical degradation is compensated by CFRP. CFRP can also provide an effective protective layer for subsequent corrosive agent penetration. The technique can overcome various drawbacks of the current repair techniques by minimizing repair time and unnecessary chipping of damaged concrete, and protect degrading concrete structures. Such excellent performances have been proven by a series of experiments. Steel rebar embedded in a concrete block brushed with lithium nitrite-based penetrating corrosion inhibitor has been proven rust-free for years. The tensile strength of CFRP sheet have been proven unchanged after the exposure of 10,000 hours of accelerated weathering conditions. The CFRP sheet has also been proven impermeable to salt ion and water by experiments. Both shear and tensile strengths of concrete columns, damaged by salt penetration and then repaired with this new technique, have been proven equal or greater than the original strengths of control column. The performance of this technique has also been granted an official “Examination and Certification of Building Preservation & Maintenance Techniques” by the authorized organizations of the Ministry of Construction, Japan in July, 1998.