Title:
Concrete After 30 Years of Exposure—Part II: Chloride Ingress and Corrosion of Steel Bars
Author(s):
Tarek Uddin Mohammed, Hidenori Hamada, and Toru Yamaji
Publication:
Materials Journal
Volume:
101
Issue:
1
Appears on pages(s):
13-18
Keywords:
cement; corrosion; steel
DOI:
10.14359/12983
Date:
1/1/2004
Abstract:
A detailed investigation on 30-year-old concrete specimens of 150 and 300 mm in diameter and height, respectively, made with ordinary portland cement (OPC), high early-strength portland cement (HES), moderate heat portland cement (MH), Type B slag cement (SCB), and alumina cement (AL) was carried out. Three steel bars were embedded at cover depths of 20, 40, and 70 mm. Carbonation depth, water- and acid-soluble chloride contents, and electrochemical and physical evaluation of corrosion were evaluated. Chloride ingress in concrete was lower for slag and alumina cements compared with the others. More corrosion over the steel bars, however, was found for alumina cement due to the porous steel-concrete interface. The surface condition of the steel bars embedded in concrete made with slag cements remains the same as the initially polished condition. Using slag cement is concluded as one of the best choices to improve the long-term durability of marine concrete structures.