Welded, sandblasted, stainless steel corrugated bars in non-carbonated and carbonated mortars: A 9-year corrosion study

• Long-term corrosion results of welded stainless steel in mortar are shown.
• Sandblasted welded stainless can be used in non-carbonated mortar with chlorides.
• Corrosion resistance of similar welded, sandblasted S32205 is very high.
• Similar welded S20430 corrodes in carbonated mortar with chlorides.
• Welded, sandblasted CS corrodes less than non-welded CS.

Three different stainless steel corrugated grades (UNS S20430, S30403 and S32205) were similar welded to stainless steel bars with the same composition and dissimilar welded to carbon steel (CS). After cleaning the welding oxides by sandblasting, the reinforcements were embedded in mortar with chlorides and some of the samples were carbonated. Corrosion activity was monitored using corrosion potential (Ecorr) and electrochemical impedance spectroscopy (EIS). After 8 years of exposure, the samples were anodically polarized. Visual evaluation of the attack was performed after another additional year of exposure. Similar welded stainless steels offer a good durability if they have been sandblasted, except for S20430 when it is embedded in carbonated mortar with chlorides. Dissimilar welded steels are active since the beginning of the exposure for both studied conditions, but sandblasting reduces the corrosion rate of CS compared to non-welded CS bars.