The effect of defects at the steel - concrete interface, exposure regime and cement type on pitting corrosion in concrete

Research output: Book/ReportReport

Abstract

Abstract
The effects of defects at the steel-concrete interface, the exposure regime, and the cement type, on the
initiation of pitting corrosion in specially designed concrete corrosion cells were investigated.
Concrete/mortar corrosion cells with cast-in mild steel electrodes representing the reinforcement were
exposed for wetting-drying cycles or submerged in NaCl solution. ParalIei field exposure testes were
carried out in sea water. The microstructure of the steel-concrete interface was altered by introduction of a
filter paper on the steel surface, by bending of the steel electrode and by compaction voids or cracks
formed at or close to the steel surface.
The results indicated that corrosion in most cases was initiated in deformed parts of steel electrodes.
Defects introduced at or close to the steel surface had a strong negative influence on the chloride threshold
for concrete exposed to wetting and drying and for field exposed concrete exposed submerged or in the
splash zone, but not for submerged laboratory exposed concrete.
The negative effect of filter paper and vo ids or cracks at the steel surface was stronger for slag cement
concrete as compared to concrete with sulphate resisting Portland cement with O or 5 % silica fume in the
binder.
The results support the idea that chioride induced pitting corrosion of steel in concrete is enforced mainly
under conditions of variable exposure conditions and in the presence of defects at the steel surface. The
results also indicate that reinforced slag cement concrete is more sensitive to the formation of, and the
effect of, cracks and other defects at the steel - concrete interface as compared to concrete bas ed on
sulfate resisting cement with O or 5 % silica fume in the binder.

Details

Authors
  • Paul Sandberg
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Materials Engineering
Original languageEnglish
PublisherDivision of Building Materials, LTH, Lund University
Number of pages26
Volume3081
Publication statusPublished - 1998
Publication categoryResearch

Publication series

NameReport TVBM
Volume3081
ISSN (Print)0348-7911

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Related research output

Paul Sandberg, 1998, Division of Building Materials, LTH, Lund University. 86 p.

Research output: ThesisDoctoral Thesis (compilation)

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