Chloride corrosion of steel rebars in mortars with fly ash admixtures

✍ Scribed by N. Kouloumbi; G. Batis

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 765 KB
• Volume: 14
• Category: Article
• ISSN: 0958-9465
• DOI: 10.1016/0958-9465(92)90014-m

✦ Synopsis

This paper presents the results of an experimental investigation of the corrosion of steel rebars in different types of mortars immersed in 3"5% sodium chloride solution. The corrosion rate of the steel bars was determined in relation to the curing time and to the addition of Greek fly ash at 15 wt% and 30 wt%. The corrosion activity was evaluated by measuring: (a) the gravimetric weight loss of the reinforcing steel bars; (b) their corrosion rate using the linear polarization resistance technique; and (c) the total and free chloride content of the various mortars used, by a selective chloride electrode. Additionally some X-ray diffraction measurements were made in order to identify the complex substances formed.

The results indicate that the addition of Greek fly ash, at both percentages, improves the corrosion behaviour of the reinforcing steel bars by lowering the free chloride content. Also, the 28 days of curing time increases the corrosion resistance of the specimens, especially those without additive. In all cases the 28-days cured specimens show a lower content of total and free chloride and a reduced corrosion rate with respect to the 1-and 7-days cured specimens.