alwc japan
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CorrosionTRANSCRIPT
Corrosion and Protectionfor Steel pile
Yoshikazu Akira, Dr. Eng.Researcher Port and Airport Research InstituteEmail: [email protected]
Independent Administrative Institution
Port and Airport Research Institute
Aiming for technologies that can contribute to the world
Its primary goal is facilitating the smooth and efficient construction of port and airports. Another major goal is researching, developing, and improving technologies for constructing ports and airports.improving technologies for constructing ports and airports.
Research fields (2006-2011)
n Research on infrastructure for homeland securityn Research for the creation of a comfortable and beautiful homelandn Research on infrastructures for a vigorous society and economy
Independent Administrative Institution
Port and Airport Research InstituteMaterials group
Long-term exposure test pier in Hasaki(1984~) Exposure test site in PARI
(1964~)
n Corrosion and corrosion protection of steel structuresn Durability of materialsn Maintenance of port and airport facilities n Others
Contents
n Corrosion of steel
Ø Corrosion Mechanism of SteelØ Corrosion of steel in under ground Environment
Corrosion of steel in marine environmentØ Corrosion of steel in marine environment
n Corrosion Protection of steel Structures
Ø Corrosion control using thickness allowance for corrosionØ protection methods
Airport facilities - D runway in HANEDA airport
2020m1100m
http://www.pa.ktr.mlit.go.jp/haneda.html
reclamationPier (Jacket)
Design service life: 100 yearsCathodic protectionCathodic protection
(Galvanic anode method, Al Alloy)(Galvanic anode method, Al Alloy)Cathodic protectionCathodic protection
(Galvanic anode method, Al Alloy)(Galvanic anode method, Al Alloy)
Stainless steel coatingStainless steel coating(PRE:44~, Thickness:0.4mm) (PRE:44~, Thickness:0.4mm) Stainless steel coatingStainless steel coating(PRE:44~, Thickness:0.4mm) (PRE:44~, Thickness:0.4mm)
Titanium CoverTitanium CoverTitanium CoverTitanium Cover
Corrosion Protection of Steel Structures
2020m1100m
Corrosion Mechanism of Steel (1)
H O+1/2O 2OH- 2OH- H O+1/2OFe2+ Fe2+
Fe(OH)2 Fe(OH)2
Neutrality environment
Steel2e-
H2O+1/2O2 2OH-
2e-
2OH- H2O+1/2O2Fe2+ Fe2+
anodecathode cathode
Corrosion Mechanism of Steel (1)
H O+1/2O 2OH- 2OH- H O+1/2OFe2+ Fe2+
Fe(OH)2 Fe(OH)2
Neutrality environment
Steel2e-
H2O+1/2O2 2OH-
2e-
2OH- H2O+1/2O2Fe2+ Fe2+
anodecathode cathode
Influence of environment
Dissolved OxygenTemperature Fluid velocity
etc
Influence of environment
Dissolved OxygenTemperature Fluid velocity
etc
Corrosion environments and corrosion tendencies in marine environment
Mean Sea Level(MSL)
Mean High Water Level (MHWL)
Corrosion rate
2. Splash zone
1. Marine atmosphere(Without corrosion protection)
< 0.1 mm/year
0.3 mm/year
Concentrated Corrosion
Occurrence at just below MLWL
Mean Sea Level(MSL)
Mean Low Water Level (MLWL)
Dep
th
3. Tidal zone
4. Submerged zone
5. Below the Sea bottomSea bottom
0.1-0.3 mm/year
0.1-0.2 mm/year
0.03 mm/year
Mechanism of concentrated corrosion under marine environment
Macro cell corrosion is caused by the difference of the Dissolved Oxygen (DO) concentration.
Anode : Fe Fe2+ + 2e-
Cathode : O + 2H O +4e- 4OH-
(Corrosion)
Cathode : O2 + 2H2O +4e- 4OH-
Tidal zone
Submerged zone
DO : high
DO : low
Cathode
Anode
Splash zone
Applicable protection methods for port steel structures
Marine atmosphere
Splash zone
Protective coating
Protective coating
Protective coating
Tidal zone
Submerged zone
Below the sea bottom
Protective coating
Cathodic protection
M.L.W.L. -1mM.L.W.L.
Protective coating
Cathodic protection
Protective coatingnon
Corrosion Mechanism of Steel (2)
Fe2+
SRB
SO42-
S2-
Non DO environmentMicrobiologically Influenced Corrosion
Steel2e-
2H+ Fe2+H2
FeS
SRB: Sulfate- Reducing Bacteria
Corrosion Mechanism of Steel (2)
Fe2+
SRB
SO42-
S2-
Non DO environmentMicrobiologically Influenced Corrosion
Steel2e-
2H+ Fe2+H2
FeSInfluence of environment
SRBSulfate, SO42-
etc
Influence of environment
SRBSulfate, SO42-
etc
SRB: Sulfate- Reducing Bacteria
Kind of bacteria related corrosion in soil
BacteriaSRBSulfate-reducing bacteria
MPBMethane-Producing Bacteria
IOBIron- Oxidation Bacteria
SOBSulfur- OxidationBacteria
IBIron Bacteria
Classification Anaerobic bacteria Aerobic bacteria
Inhabiting Clay, Sludge, Acid environment
Soil, Oil field, Sulfur Groundwater
that contains Inhabiting environment
Clay, Sludge, Reclaimed ground, rust etc
environmentof sulfuric acid
Sulfur deposit, Sewage
that contains Fe and Mn
pH 5.0 ~ 9.5 Neutrality 2.0 ~ 2.5 2.0 ~ 3.5 6 ~ 8
Nourishment SO42-
Lactic acid Acetic acid Fe2+ S, FeS Fe2+, Mn2+
HCO3-, CO32-
Reaction Reducing SO42- to S2-
Reactingmethane
Oxidizing Fe2+ to Fe3+
Oxidizing S or FeS to sulfuric acid
Oxidizing Fe(OH)2 to FeOOH orFe3O4
Microbiologically Influenced Corrosion
Exposure environment:Artificial sewage
(mg/L)Glucose 250(NH4)SO4 142KH2PO4 15.0KH2PO4 15.0MgSO4-7H2O 11.3CaCl2-2H2O 1.4FeCl3 0.1
Corrosion of Steel in under ground Environment
p Uneven environment due to stir soil
p Existing groundwaterp Connected to RC structures
Variation of kinds of soilp Variation of kinds of soilex. Moisture, Humidity and Soil quality
Aver
age
of c
orro
sion
rat
e (m
m/y
r)Corrosion rate of Steel in under ground Environment
Fig. 6.3.2
Refer: S. Moriya, S. Murase, K. Nakano, The statistical investigation into corrosion loss of the steel pope pile and sheet pipe pile under ground environment, Search for Civil Engineering Journal, 47-3, 2005 (Japanese)
Aver
age
of c
orro
sion
rat
e (m
m/y
r)
Exposure time (years)
Protection of rust layerProtection of rust layer
For rust covers penetration of O2
and H2O, corrosion rate has decreased with a lapse of time
Aver
age
of c
orro
sion
loss
(m
m/y
r)
(68.3%)(95.5%)(99.7%)
Poor condition of O2Poor condition of O2
O2 Supplied- from penetration from
Corrosion loss of Steel in under ground Environment
Ref. S. Moriya, S. Murase, K. Nakano, The statistical investigation into corrosion loss of the steel pope pile and sheet pipe pile under ground environment, Search for Civil Engineering Journal, 47-3, 2005 (Japanese)
Aver
age
of c
orro
sion
loss
(m
m/y
r)
Ave.
Service time (years)
(68.3%) - from penetration fromground due to air
- from rain or groundwater
Amount of dissolved oxygen decrease, as depth from ground deep
Aver
age
of c
orro
sion
loss
(m
m/y
r)
(68.3%)(95.5%)(99.7%)
Poor condition of O2Poor condition of O2
O2 Supplied- from penetration from
Corrosion loss of Steel in under ground Environment
Ref. S. Moriya, S. Murase, K. Nakano, The statistical investigation into corrosion loss of the steel pope pile and sheet pipe pile under ground environment, Search for Civil Engineering Journal, 47-3, 2005 (Japanese)
Aver
age
of c
orro
sion
loss
(m
m/y
r)
Ave.
Service time (years)
(68.3%) - from penetration fromground due to air
- from rain or groundwater
Amount of dissolved oxygen decrease, as depth from ground deep
Weight loss of steel due to corrosion after 100 years in common condition in soil environment was predicted about 1mmWeight loss of steel due to corrosion after 100 years in common condition in soil environment was predicted about 1mm
Other Factor of Corrosion in Soil Environment
Potential of Hydrogen (pH) in soilPotential of Hydrogen (pH) in soil
pH less than 4 : Heavy corrosion
Organic acid (ex. Humic acid) : Heavy corrosion ??
Alkalinity environment : no influence
PO43-, SiO32-, CO32-: reducing corrosion
Alkalinity environment : no influence
Microbiologically Influenced CorrosionMicrobiologically Influenced Corrosion
Constituents of soilConstituents of soil
CO2, SO2, HS : accelerating corrosion
Chloride ion, Sulfate : accelerating corrosion
Example of result of investigation (1)
Investigation of corrosion in PWRIInvestigation of corrosion in PWRI
Exposure time: 17 years
0.0240.0030.009
0.024
0.01 0.02 0.030
0
Corrosion rate (mm/yr)
-5Protection method0.2m~ : painting
0.002
0.024
0.004
0.001
0.002
0.003
5
10
15
20
25
30
35
40
0.2m~ : painting~0.2m : no protection
hardly corrodes
Example of result of investigation (2)
Corrosion rate (mm/yr)Both sides
Dep
th o
f gr
ound
sur
face
(m
)D
epth
of
grou
nd s
urfa
ce (
m)
2years5years
10years
Other index
n Relationship between resistivity of soil and corrosion rate
Corrosion rate Resistivity of soil (ohm cm)
Very high 0 ~ 500
High 500 ~ 1000
Medium 1000 ~ 2000
small 2000 ~ 10000
Very small 10000 <
Countermeasure of corrosion(corrosion protection method)
CountermeasureCountermeasure
Protection methodProtection method
Coating protectionCoating protection
Organic coatingOrganic coating
Inorganic coatingInorganic coating
PaintingPainting
Organic coatingOrganic coating
Metallic coatingMetallic coating
Corrosion control using thickness allowance for corrosionCorrosion control using thickness allowance for corrosion
Cathodic protectionCathodic protection
Using anti-corrosion materialUsing anti-corrosion material
Environment controlEnvironment control
Combined coatingCombined coatingMortar coatingMortar coating
Countermeasure of corrosion(corrosion protection method)
CountermeasureCountermeasure
Protection methodProtection method
Coating protectionCoating protection
Organic coatingOrganic coating
Inorganic coatingInorganic coating
PaintingPainting
Organic coatingOrganic coating
Metallic coatingMetallic coating
Corrosion control using thickness allowance for corrosionCorrosion control using thickness allowance for corrosion
Cathodic protectionCathodic protection
Using anti-corrosion materialUsing anti-corrosion material
Environment controlEnvironment control
Combined coatingCombined coatingMortar coatingMortar coating
Painting
・The ease of application ・Possible to apply to new and established structures・Structural service life : several ~more than 10 yearsseveral ~more than 10 years
Need of repair for long-term use
Primer Zinc rich paint
Middle coat Epoxy, Polyurethane, Polyester, (tar-epoxy) etc.
Top coat Polyurethane, Silicon, Fluoride paint
Heavy protective painting system
20 years exposure
Organic coating
Polyethylene lining
Underwater organic coatingConstruction by underwater paint
Only applicable to newly-constructed structures
Polyethylene liningsteel
polyethylene
adhesive
special surface treatment
Inorganic coating – mortar coating
Str
uct
ure
An example of Mortar / FRP cover method
FRP cover
Mortar
Str
uct
ure
FRP cover
Inorganic coating – electro-deposition
ElectrocoatingCaCO3
Local energyLocal energy・・wind forcewind force・・wave forcewave force・・solar powersolar powerPower supplyPower supply CaCO3
Mg(OH)2
Power supplyPower supply
DC power
Stru
ctur
e
anode
Seawater Ca2+
Mg2+
Inorganic coating – metallic coating
Covering steel with high corrosion resistance material
ex. Titanium, Stainless steel…
Classifications for this methodTitanium coating HANEDA airport
Thermal spraying(Al, Zn, Al-Zn alloy …)
Titanium coating
Stainless steel coating
Titanium clad
Stainless steel clad
Plating (Al, Zn)
Tokyo-bay Aqua Line (Route 409)
FUKUYAMA port12yearsAl Zn
Cathodic protection
Galvanic anode methodGalvanic anode method Impressed current methodImpressed current method
MLWL
-
MLWL –1m
DC Power Source+
HWL
Anode (Al, Zn, Mg )
Protective Current
HWL
MLWL –1m
Insoluble anode
Protective Current
Finally
Detailed specification design
Performance based design
n Structural performancen Durability
Corrosion of steel
Maintenance based design of steel structures
Life Cycle Management System
Maintenance planning
Regular inspection
Database
Input & reference
History of utilization
Designing and environmental condition
Proposal on countermeasures
Optimization of management and reduction of LCC
Performance evaluation
timeperf
orm
ance
Database • Inspection • Prediction• Countermeasure
Input & reference
Input & reference
Designing and environmental condition
Remaining service life and future utilizing plan
LCM System
Book on corrosion protection of steel pipe pileTitle: UndecidedAuthors: Joint research group
Dr. HamadaDr. AbeMr. ShimizuDr. Akira et al
Publication is scheduled in March, 2010.
Thank you very much for your kind attentionThank you very much for your kind attention
Technical Standard and Commentaries for Port and Harbour Facilities in Japan
It was revised in 2007.Shifted from specification design
to performance based designThe demanded performance should keep The demanded performance should keep being satisfied for the design service life.
ØAppropriate designØAppropriate constructionØAppropriate maintenance
MaterialsIt is necessary to select the using material in consideration of the quality, durability and economy.
Corrosion protection and repair of port steel structures
It will be revised in 2009.Shifted from specification design
to performance based design
Contents Contents n Corrosion of steel under marine environmentn Note on selection of corrosion protection methodsn Design of protection methodsn Construction of protection methodsn Maintenance and repair of protection methodsn Repair and reinforcement of steel structures