A study on the corrosion of reinforcing bars in alkali-activated fly ash mortars under wet and dry exposures to chloride solutions. (September 2016)

• Record Type: Journal Article
• Authors: Monticelli, C.; Natali, M.E.; Balbo, A.; Chiavari, C.; Zanotto, F.; Manzi, S.; Bignozzi, M.C.
• Is Part Of: Cement and concrete research. Volume 87(2016)
• Page Start: 53
• Page End: 63
• Publication Date: 2016-09
• Subjects: D. Alkali activated cement -- C. Corrosion -- D. Chloride -- C. Mechanical properties -- B. Microstructure; Cement -- Periodicals; Cement -- Research -- Periodicals; Concrete -- Periodicals; Concrete -- Research -- Periodicals; Ciment -- Périodiques; Béton -- Périodiques; Cement; Concrete; Periodicals; 620.135
• DOI: 10.1016/j.cemconres.2016.05.010
• Languages: English
• ISSNs: 0008-8846

Abstract

Abstract: This research investigates the corrosion protection afforded to the embedded rebars by room temperature-cured alkali-activated mortars, based on class F fly ash (FA), during wet and dry (w/d) exposures to 0.1 M NaCl solution. The results were compared to those obtained in a traditional cement-based mortar (REF). The rebar corrosion behaviour was characterized by corrosion potentials (Ecor ) and potentiostatic polarization resistance (Rp ) measurements, polarization curve recording and electrochemical impedance spectroscopy (EIS). The information collected suggested that FA mortars afforded a lower corrosion protection to the rebars and the reason was investigated by microstructural, physical–mechanical and chemical analyses of the mortars. FA mortars were found to undergo a fast carbonation, so that depassivation of the rebars occurred concurrently, in spite of a limited total chloride content inside these mortars. REF mortar was much less susceptible to carbonation and rebar corrosion started when a sufficiently high chloride concentration was built up.