Corrosion protection by coatings on prestressed steel

It is well known that the durability of prestressed concrete structures is reduced as a result of the corrosion of steel in concrete. This paper presents various evaluation methods for selecting a suitable coating system for steel and concrete to prevent corrosion under static load conditions. For this, a specimen of 7-mm-diameter high-tension steel is taken and experiments have been conducted with 150-mm by 150-mm by 300-mm concrete prisms using cement polymer composite coating (CPCC) and fusion-bonded epoxy coating (FBEC). The performance of these coating systems has been compared with an uncoated controlled specimen in an aggressive environment by keeping them immersed in 3% sodium chloride (NaCl) + 0.04 sodium hydroxide (NaOH) solution and subjecting them to an accelerated corrosion. A potential of 2 V has been applied for pull-out bond strength. Based on the results of experimental studies, the composition of the coating system for the prevention of corrosion has been evaluated. © 2005, NACE International.