Long-Term Monitoring of Carbon Fiber-Reinforced Polymer-Wrapped Reinforced Concrete Columns Under Severe Environment

Corrosion of reinforcing steel in concrete structures is a major problem affecting North American infrastructure. Fiber-reinforced polymers (FRPs) have outstanding properties such as high strength, durability, and resistance to electrochemical corrosion. The use of FRP wraps and their effectiveness in restoring the integrity of corroded reinforced concrete structures, as well as their impact on corrosion activity, is still in question. This paper focuses on inducing corrosion in columns using an aggressive environment that simulates natural corrosion, and the use of carbon FRP (CFRP) wraps in repair of corrosion-damaged reinforced concrete columns. The experiment included 12 large-scale circular columns 300 x 1200 mm (12 x 48 in.). Ten columns were cast with 3% NaCl (by weight of cement) premixed with the mixing water in the outer 75 mm (3 in.) thick ring. The two remaining columns were uncontaminated and used as control specimens (one wrapped and one unwrapped). The ten chloride-laden columns were corroded using an aggressive environment. The experiment incorporated electrochemical chloride extraction (ECE) treatment on four of the columns followed by CFRP wrapping on eight columns. The research concluded that the CFRP wraps applied over corrosion-damaged reinforced concrete columns will decrease the corrosion rate of the reinforcement and restore the structural integrity of the column. The ECE and wrapping combination provided the best protection against future corrosion. The application of the wraps will be more effective when applied at earlier stages of the corrosion. The strength of the wrapped columns was also very close to that of the wrapped control column.