Effect of cement type on chloride binding and corrosion of steel in concrete
- South Bank Univ., London (United Kingdom). School of Architecture and Civil Engineering
Chloride binding and its influence on the rate of reinforcement corrosion has been investigated in a range of mixes by, respectively, pore solution analysis and measuring the galvanic current in macro corrosion cells formed by embedding mild steel bars in two layers of concrete. For chloride derived from NaCl and introduced at the time of mixing, chloride binding occurred in the order of: GGBS > PFA > OPC > SF and the amount of unbound (ie free) chloride increased with increasing chloride content. However the corrosion rates occurred in the order of PFA > SF > GGBS > OPC at 1% Cl{sup {minus}} and PFA > OPC > GGBS > SF at 3% Cl{sup {minus}}. The corrosion rates increased with increasing chloride content for all mixes due to an increase in the amount of free chloride. The higher rates of corrosion for PFA (and GGBS at 1% Cl{sup {minus}}) compared with OPC was attributable to a reduction in the OH concentration as a result of the pozzolanic reaction. The relatively low rate of corrosion for SF at 3% Cl{sup {minus}} is thought to largely depend upon the physical characteristics of the matrix rather than the pore solution chemistry.
- OSTI ID:
- 63245
- Journal Information:
- Cement and Concrete Research, Journal Name: Cement and Concrete Research Journal Issue: 4 Vol. 25; ISSN 0008-8846; ISSN CCNRAI
- Country of Publication:
- United States
- Language:
- English
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