DETERIORATION CHARACTERISTICS OF RE-PAINTED Sn-BEARING STEEL IN ATMOSPHERE CONTAINING CHLORIDE

Abstract

 To evaluate deterioration characteristics of re-painted steel structure is crucially meaningful for making maintenance plan to painted steel structure in the future. In order to clarify the effect of Sn-bearing steel on the deterioration characteristics of re-painted steel structure, its corrosion behavior at paint defect of paint film on the rusted surface having difference base texture and residual chlorine was investigated by exposure test and accelerated corrosion cycle test. Sn-bearing steel showed a similar corrosivity to conventional steel (SM490 steel) in case of the accelerated corrosion combined cycle test composed of long wetting time, while it showed superior corrosion resistance in case of the exposure test. It is found that the evaluation using test specimens repainted on its surface remaining old paint film is simulated their deterioration characteristics accurately rather than that of using test specimens painted on its rusted full surface. For more quantitative evaluation of deterioration characteristics of re-painted steel structure, accelerated corrosion test considering rust layer, residual chloride and wetting time at surface of steel is supposedly required.