abstract
Red mud, the main waste generated in aluminum and alumina production by the Bayer process, is considered "hazardous" due to its high pH. The characteristic of high alkalinity associated with the presence of alumino-silicates facilitates the assimilation and formation of compounds by reaction with chloride ions. The high pH also provides greater protection of rebars, which is reflected in the low corrosion potential and high electrical resistivity (filler effect) of concrete. In this study, the chloride concentration was monitored by measuring the conductivity of the anolyte. Red mud proved to be a promising additive for concrete to inhibit the corrosion process. The corrosion potential was monitored by electrochemical measurements and the electrical resistivity was evaluated using sensors embedded in concrete test specimens. The results showed that the addition of red mud is beneficial to concrete, reducing its chloride migration rate (diffusion coefficients) and corrosion potential and increasing its electrical resistivity. (C) 2011 Elsevier Ltd. All rights reserved.
keywords
CHLORIDE DIFFUSION-COEFFICIENTS; DURABILITY CHARACTERISTICS; ELECTRICAL-CONDUCTIVITY; EAF SLAG; PERMEABILITY; AGGREGATE; CEMENTS; BAUXITE; WASTE
subject category
Construction & Building Technology; Materials Science
authors
Ribeiro, DV; Labrincha, JA; Morelli, MR
our authors
João António Labrincha Baptista
Full professoracknowledgements
The authors wish to thank CNPq - National Council for Scientific and Technological Development (Brazil), PPGCEM/UFSCar - Postgraduate Program in Materials Science and Engineering at the Federal University of Sao Carlos (Brazil), and UA/DECV - Department of Ceramics and Glass Engineering, University of Aveiro & CICECO (Portugal) - Project FCT-PTDC/CTM/65243/2006.