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

Sandberg, Paul LU (1998) In Report TVBM 3081.
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... (More)
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. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Book/Report
publication status
published
subject
in
Report TVBM
volume
3081
pages
26 pages
publisher
Division of Building Materials, LTH, Lund University
external identifiers
  • other:TVBM-3081
ISSN
0348-7911
language
English
LU publication?
yes
id
fa981216-1745-49c7-b73b-f6d7e03659ca (old id 1529238)
date added to LUP
2010-01-18 11:33:25
date last changed
2016-04-16 04:30:49
@techreport{fa981216-1745-49c7-b73b-f6d7e03659ca,
  abstract     = {Abstract<br/><br>
The effects of defects at the steel-concrete interface, the exposure regime, and the cement type, on the<br/><br>
initiation of pitting corrosion in specially designed concrete corrosion cells were investigated.<br/><br>
Concrete/mortar corrosion cells with cast-in mild steel electrodes representing the reinforcement were<br/><br>
exposed for wetting-drying cycles or submerged in NaCl solution. ParalIei field exposure testes were<br/><br>
carried out in sea water. The microstructure of the steel-concrete interface was altered by introduction of a<br/><br>
filter paper on the steel surface, by bending of the steel electrode and by compaction voids or cracks<br/><br>
formed at or close to the steel surface.<br/><br>
The results indicated that corrosion in most cases was initiated in deformed parts of steel electrodes.<br/><br>
Defects introduced at or close to the steel surface had a strong negative influence on the chloride threshold<br/><br>
for concrete exposed to wetting and drying and for field exposed concrete exposed submerged or in the<br/><br>
splash zone, but not for submerged laboratory exposed concrete.<br/><br>
The negative effect of filter paper and vo ids or cracks at the steel surface was stronger for slag cement<br/><br>
concrete as compared to concrete with sulphate resisting Portland cement with O or 5 % silica fume in the<br/><br>
binder.<br/><br>
The results support the idea that chioride induced pitting corrosion of steel in concrete is enforced mainly<br/><br>
under conditions of variable exposure conditions and in the presence of defects at the steel surface. The<br/><br>
results also indicate that reinforced slag cement concrete is more sensitive to the formation of, and the<br/><br>
effect of, cracks and other defects at the steel - concrete interface as compared to concrete bas ed on<br/><br>
sulfate resisting cement with O or 5 % silica fume in the binder.},
  author       = {Sandberg, Paul},
  institution  = {Division of Building Materials, LTH, Lund University},
  issn         = {0348-7911},
  language     = {eng},
  pages        = {26},
  series       = {Report TVBM},
  title        = {The effect of defects at the steel - concrete interface, exposure regime and cement type on pitting corrosion in concrete},
  volume       = {3081},
  year         = {1998},
}