Effect of fly ash on the corrosion performance and structural integrity of stainless steel concrete rebars in acid rain and saline environments

• Main Authors: Angeliki G. Lekatou, Sofia Tsouli, Christos Nikolaidis, Spyridon Kleftakis, Ilias K. Tragazikis, Theodoros E. Matikas
• Format: Article
• Language: English
• Published: Gruppo Italiano Frattura 2019-10-01
• Series: Frattura ed Integrità Strutturale
• Subjects: 304l rebars; fly ash; acid rain; reverse polarization; salt spray¬ing; tensile properties
• Online Access: https://www.fracturae.com/index.php/fis/article/view/2611/2749

The corrosion behavior of 304L stainless steel rebars in an alkaline solution simulating new concrete subjected to acid rain attack and a mildly to slightly acidic solution simulating corroded cover concrete that ex¬posed the reinforcement to direct acid rain attack, was investigated by reverse polarization. Both solutions contained Ca(OH)2 and fly ash (0-25 wt.% of the dry mixture). Concrete cubes containing 0-25 wt.% fly ash and reinforced with 304L rebars were subjected to salt spraying for 4 m. Although the polar¬ization behaviors in the two electrolytes were different, the relative trends with respect to the fly ash contents were similar. The beneficial effect of fly ash (up to 20 wt.%) on the corrosion resistance of 304L rebars was de¬mon¬strated. How¬ever, a deteriorating effect was realized at 25 wt.% addition. Partial re¬placement of cement by fly ash did not significantly affect the tensile properties of the 304L rebar before or after 4 m of salt spraying. The elastic modulus and percent elongation presented a slight decrease after 4 m of salt spraying, ir¬respectively of FA content. Corrosion-wise, 304L can replace 316L stainless steel provided that FA has been added to the concrete mixture, even at low contents (10 or 15 wt.%).