Corrosion resistance performance of high-volume fly-ash self-compacting concretes

The corrosion performance of self-compacting concretes with high-volume replacements of fly ash was evaluated by some electrochemical techniques. In this study, eight self-compacting fly-ash concretes of various strength grades were designed at desired fly ash percentages of 0, 10, 30, 50, 70 and 85%, and were compared with five different mixtures of normal vibrated concretes at equivalent strength grades. The corrosion characteristics of the developed concretes were studied through the measurement of resistivity, pH, carbonation depth, half-cell potential and corrosion rate. Results demonstrate that self-compacting concretes at all levels of fly ash replacement performed significantly better than the corresponding normal vibrated concretes. This can be mainly attributed to the pozzolanic activity of fly ash. The carbonation was, however, higher in low- and medium-strength self-compacting concretes compared to the normal concretes.