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09/03/2011 1
SILANES
Sydney Opera House
protected with MASTERSEAL 360 TE
John Halsall
Regional Business Segment
Manager
Repair & Grouts
09/03/2011 2
What are Silanes?
• Chemical Compound of Silicone and Hydrogen
• Used as an Adhesion Promoter in
- Adhesives and sealants
- Coatings
- Fillers and Pigments
• Hydrophobic Treatment for Building / Structure
Protection
Silane RSi(OR´)3
09/03/2011 3
• Small Reactive Molecules
• Penetrate Deep Into The Substrate
• Chemically Bond With The Concrete
• Form A Water Vapour Permeable Protective Barrier
Against Harmful Waterborne Substances
S iO
O
O
S iO
S i
XO
R
S iS i
OO
OS i
OH
fR f
Substrate e.g. concreteSubstrate e.g. concreteSubstrate e.g. concreteSubstrate e.g. concrete
Silane MoleculeSilane MoleculeSilane MoleculeSilane Molecule
What are Silanes?
09/03/2011 4
Si
• Consider Silanes As Umbrella Protecting The
Substrate
What are Silanes?
09/03/2011 5
Silanes Make The Surface Of the Substrate Hydrophobic.
They Penetrate Deeply Into Substrate And React With The Surface
Of The Pore System.
dissolved
chlorides
water vapor
Dis
so
lve
d C
hlo
ride
s capillary pore
OH-functionsilanized
capillary pore
alkylsiloxane
How Do Silanes Work?
09/03/2011 6
Due To The Protective Function (Umbrella) Silanes Change The
Surface From Hydrophilic To Hydrophobic.
Non Modified Hydrophilic
Mineral Substrate Causes
Capillary Suction
Silane Treated Hydrophobic
Porous Mineral Substrate.
No Ingress Of Water
How Do Silanes Work?
09/03/2011 7
Water Absorption On Structural Concrete
0
1
2
3
4
0 1 2 3 4 5 6 7
Immersion [days]
Wa
ter
Ab
so
rpti
on
[%
]
Masterseal 360/Protectosil CIT
untreated
09/03/2011 8
Masterseal 360 TE (Protectosil BHN)
• Field Study – Zeebrugge Harbour Wall 1993 -
2005
09/03/2011 9
Silanes Vs Siloxanes
� Silanes are small molecules and Penetrate Deeply into the Substrate and
chemically react with the pore surface (3-10mm deep). This chemical
reaction and deep penetration give a life > 10 years
� Siloxanes are big molecules which form a film within the outer pores
system that creates a water barrier on any mineral building material with
pores (Bricks, roof tiles, concrete). This material is eventually washed out
of the pores and thus has a life of around 5 years..
SilaneRSi(OR´)3
SiloxaneSi O
OR
RO Si O Si O Si OR
OR OR OR
09/03/2011 10
No significant penetration
of a siloxane resin based
water repellent
Siloxane Treated
Silanes Vs Siloxanes
Penetration of the silane
into dense concrete
HIGH PENETRATION DEPTH = LONG SERVICE LIFE
Surface modification
can cause less adhesion
of a succeeding coating
No change in surface appearance
Silane Treated
09/03/2011 11
• Clear Liquids (Cream)
• Low Viscosity (10 times less than water)
• Simply Applied
• Highly Water Vapour Permeable
• No Change Of Surface Appearance
Silane Protection of Buildings / Structures
‘MASTERSEAL 360TE’
09/03/2011 12
Advantages of Silanes
They can avoid damage caused by
- Chloride induced corrosion of reinforcement
- Carbonation induced corrosion
- Freezing / thawing
- Acid Rain
- Alkali silica reaction
(Na,K)-Si-OH gel reacts with Ca → solidification → water absorbtion and
swelling
- Sulfate Attack
- Reduce Efforvescence
09/03/2011 13
• Storebaelt Bridge
• Sydney Opera House
• Zeebrugge Harbour
References
09/03/2011 14
Summary - Silanes
• Very effective for reduction of water absorption
• Excellent penetration depth
• Completely water vapour permeable
• Long-term stability over decades, proved in various field
studies
• Does not change surface and thus will accept
subsequent coatings
• Coated surfaces have a longer service life
• Repels various dissolved pollutants
• Easy spray application
• Available in various forms (is available in liquid, gel and
water dispersed forms
09/03/2011 15
Silane Based Corrosion Protection
09/03/2011 16
TYPES OF CORROSION PROTECTION
• Mechanical Methods
– Coating Of The Steel Reinforcement (Emaco Nanocrete AP)
– Coating Of Concrete Surface (Masterseal Acylics)
– Non Corrodeable Reinforcement (SS, Carbon , Fibreglass)
• Electrochemical Methods
– Chloride Ion Extraction
– Galvanic Cathodic Protection (
– Impressed Current Cathodic Protection
• Chemical Methods
– CORROSION INHIBITORS (PROTECTOSIL CIT)
09/03/2011 17
What Is Protectosil® Cit ?
Silane Based Corrosion Inhibitor To Reduce Active But Not Yet Visible
Corrosion (Ie Rusting Has Not Yet Resulted In Cracks, Spalling, Rust
Stains Etc)
Protectosil® CIT Consists Of Small, Reactive Molecules, That
Penetrate Deeply Into The Concrete And React With The Concrete
Pore Walls
⇒⇒⇒⇒ Prevents Ingress Of More Water, Chloride Ions And Other
Pollutants
⇒⇒⇒⇒ Can React With The Oxide Layer Of The Rebar
Strengthening Of The Passivation Layer
09/03/2011 18
Incipient Anodes (Ring Anode Effect)
09/03/2011 19
Corrosion In Reinforced Concrete
anode
cathode
cathode
4 Fe 4 Fe4 Fe 4 Fe4 Fe 4 Fe4 Fe 4 Fe2+2+2+2+ + 8 e+ 8 e+ 8 e+ 8 e----
4 Fe4 Fe4 Fe4 Fe2+2+2+2+ + O+ O+ O+ O2222 + 8OH+ 8OH+ 8OH+ 8OH---- 4 FeOOH + 2 H4 FeOOH + 2 H4 FeOOH + 2 H4 FeOOH + 2 H2222OOOO
2 O2 O2 O2 O2222 + 4 H+ 4 H+ 4 H+ 4 H2222O + 8 eO + 8 eO + 8 eO + 8 e---- 8 OH8 OH8 OH8 OH----
e----
e----
09/03/2011 20
Specimen SetSpecimen SetSpecimen SetSpecimen Set----up For Laboratory up For Laboratory up For Laboratory up For Laboratory
Testing Of Corrosion Testing Of Corrosion Testing Of Corrosion Testing Of Corrosion
InhibitorsInhibitorsInhibitorsInhibitors
FHWA TEST METHOD
25 mm25 mm25 mm25 mm
25 mm25 mm25 mm25 mm
PONDED SALTWATER
HUMIDITY PROBE
DRAWING NOT TO SCALE
09/03/2011 21
Test Set-up
Filled with15 % NaCl
concretehumidity
Acrylic glass edging
Sensor for
Steel rebars
Steel
rebars
The idea is to cycle the salt water ponding to drive the salt into the
concrete to initiate corrosion much faster than in real life
09/03/2011 22
Decrease in Corrosion Current Following
Application Of Protectosil Cit
Days pondingDays pondingDays pondingDays ponding
0000
Corrosion current [µA]
Corrosion current [µA]
Corrosion current [µA]
Corrosion current [µA]
100100100100
200200200200
300300300300
400400400400
500500500500
600600600600
700700700700
800800800800
untreated
After CIT applicationAfter CIT applicationAfter CIT applicationAfter CIT application
drying / CIT application
wetting/drying cycles wetting/drying cycles
Concrete sepcimen according to FHWA (30x30x17,5 cm), 15 % NaCl solution, Total
corrosion current
(macro- + microcell corrosion) measured,
> 90 % reduction of corrosion current> 90 % reduction of corrosion current> 90 % reduction of corrosion current> 90 % reduction of corrosion current
09/03/2011 23
Performance On Cracked ConcretePerformance On Cracked ConcretePerformance On Cracked ConcretePerformance On Cracked Concrete
Cracks are 0.3 mm wide
and 25 mm deep
Corrosion Corrosion Corrosion Corrosion
products products products products
visiblevisiblevisiblevisible
09/03/2011 24
PROTECTOSIL® CIT PREVENTS CORROSION ON
CRACKED CONCRETE
0000
100100100100
200200200200
300300300300
400400400400
500500500500
600600600600
0000 1111 5555 10101010 15151515 20202020 25252525 30303030 35353535 40404040 45454545 48484848
Time Time Time Time ---- WeeksWeeksWeeksWeeks
Corrosion current [µA]
Corrosion current [µA]
Corrosion current [µA]
Corrosion current [µA]
UntreatedUntreatedUntreatedUntreated
Protectosil CITProtectosil CITProtectosil CITProtectosil CIT
09/03/2011 25
ProtectosilProtectosilProtectosilProtectosil®®®® Cit Reduces Cit Reduces Cit Reduces Cit Reduces
Existing ActiveExisting ActiveExisting ActiveExisting Active Corrosion On Corrosion On Corrosion On Corrosion On
Cracked ConcreteCracked ConcreteCracked ConcreteCracked Concrete
0000
100100100100
200200200200
300300300300
400400400400
500500500500
600600600600
0000 1111 5555 10101010 15151515 20202020 25252525 30303030 35353535 40404040 45454545 48484848
Current, µA
Current, µA
Current, µA
Current, µA
Weeks of Salt Water ExposureWeeks of Salt Water ExposureWeeks of Salt Water ExposureWeeks of Salt Water Exposure
Slabs TreatedSlabs TreatedSlabs TreatedSlabs Treated
with CITwith CITwith CITwith CIT
UntreatedUntreatedUntreatedUntreated
Protectosil Protectosil Protectosil Protectosil
CITCITCITCIT
09/03/2011 26
Application Of Protectosil® Cit
• Spalled concrete and delaminations are repaired; totally corroded
reinforcement has to be replaced; the surface has to be cleaned from
dust, effluorences and oil
• Protectosil® CIT should be applied to ALL concrete using low-pressure
pumping equipment
09/03/2011 27
Field Performance of Field Performance of Field Performance of Field Performance of
ProtectosilProtectosilProtectosilProtectosil®®®® CITCITCITCIT
Balconies Near Salt WaterBalconies Near Salt WaterBalconies Near Salt WaterBalconies Near Salt Water
• 20 Year Old Building Located in Florida, USA20 Year Old Building Located in Florida, USA20 Year Old Building Located in Florida, USA20 Year Old Building Located in Florida, USA
• Total Repairs = US $ 1.2 millionTotal Repairs = US $ 1.2 millionTotal Repairs = US $ 1.2 millionTotal Repairs = US $ 1.2 million
• Repairs Made and ProtectosilRepairs Made and ProtectosilRepairs Made and ProtectosilRepairs Made and Protectosil®®®® CIT Applied in 1994CIT Applied in 1994CIT Applied in 1994CIT Applied in 1994
09/03/2011 28
• Spalls and Delaminations were repaired using standard methodsSpalls and Delaminations were repaired using standard methodsSpalls and Delaminations were repaired using standard methodsSpalls and Delaminations were repaired using standard methods
• ProtectosilProtectosilProtectosilProtectosil®®®® CIT was applied to all the exposed concreteCIT was applied to all the exposed concreteCIT was applied to all the exposed concreteCIT was applied to all the exposed concrete
• Corrosion testing was performed annually to verify performanceCorrosion testing was performed annually to verify performanceCorrosion testing was performed annually to verify performanceCorrosion testing was performed annually to verify performance
Field Performance of Field Performance of Field Performance of Field Performance of
ProtectosilProtectosilProtectosilProtectosil®®®® CITCITCITCIT
Balconies Near Salt WaterBalconies Near Salt WaterBalconies Near Salt WaterBalconies Near Salt Water
09/03/2011 29
0000
0000....2222
0000....4444
0000....6666
0000....8888
1111.0.0.0.0
1111....2222
1111....4444
1111....6666
1994199419941994 1994199419941994 1995199519951995 1996199619961996 1997199719971997 1998199819981998 1999199919991999 2000200020002000 2001200120012001
Corrosion Rate Before CITCorrosion Rate Before CITCorrosion Rate Before CITCorrosion Rate Before CIT
Corrosion Rate After CITCorrosion Rate After CITCorrosion Rate After CITCorrosion Rate After CIT---- steel steel steel steel
remains in passive condition for remains in passive condition for remains in passive condition for remains in passive condition for
at least 8 years at least 8 years at least 8 years at least 8 years
Corrosion c
Corrosion c
Corrosion c
Corrosion current, µA
urrent, µA
urrent, µA
urrent, µA/cm
/cm
/cm
/cm22 22
>>>>1.0 1.0 1.0 1.0 µAµAµAµA/cm/cm/cm/cm2222 = < 2yrs to defects= < 2yrs to defects= < 2yrs to defects= < 2yrs to defects
< 0.2 < 0.2 < 0.2 < 0.2 µAµAµAµA/cm/cm/cm/cm2222 = passive conditions= passive conditions= passive conditions= passive conditions
Field Performance of Field Performance of Field Performance of Field Performance of
ProtectosilProtectosilProtectosilProtectosil®®®® CITCITCITCIT
Balconies Near Salt WaterBalconies Near Salt WaterBalconies Near Salt WaterBalconies Near Salt Water
09/03/2011 30
Field Performance of Protectosil® CIT
Bridge Deck Exposed to Deicer Salts
• 1.8 miles long bridge
• 98,000 m2 of concrete deck
• Built in 1970
• Corrosion damage due to
chloride
ingress & transverse
cracking
GeCor 6
Linear
Polarisation
test
apparatus
09/03/2011 31
Commodore Barry Bridge - Corrosion Rate
Measurements from 1997 to 2000
0000
0000....1111
0000....2222
0000....3333
0000....4444
0000....5555
0000....6666
0000....7777
0000....8888
0000....9999
B GantryB GantryB GantryB Gantry E GantE GantE GantE Gantrrrryyyy F GantryF GantryF GantryF Gantry
TreatedTreatedTreatedTreated
UntreatedUntreatedUntreatedUntreated
Actual core showing
nature of transverse
cracks
Corrosion c
Corrosion c
Corrosion c
Corrosion current, µA
urrent, µA
urrent, µA
urrent, µA/cm
/cm
/cm
/cm22 22
> > > > 0.5 0.5 0.5 0.5 ---- 1.0 1.0 1.0 1.0 µAµAµAµA = 3= 3= 3= 3----10yrs to deterioration10yrs to deterioration10yrs to deterioration10yrs to deterioration
< 0.2 < 0.2 < 0.2 < 0.2 µAµAµAµA/cm/cm/cm/cm2222 = passive conditions= passive conditions= passive conditions= passive conditions
09/03/2011 32
Protectosil® CIT – Independant testing
J Bennett Associates - USA
‘Protectosil by Degussa Corporation effectively reduced
corrosion of reinforcing steel in ASTM G109JJ.’
Mott MacDonald - UK
‘..an effective alternative to the existing methods of durability
enhancement for reinforced concrete and the avoidance of
secondary effects such as incipient anode behavior.’
SGK - Switzerland
J.‘Protectosil CIT treatment resulted in a clear decrease
in corrosion current, and even repassivation is observed
on the sensors initially showing active corrosion.’
09/03/2011 33
SUMMARY
� Protectosil CIT should be considered as an solution in part of A long
term repair package
- Effective preventative measure to prevent incipient anodes
- Excludes of water borne chlorides
- Strengthens the passive layer on the steel surface
- Simply applied
- Cost effective
- Proven track record
- Backed up by independent testing
09/03/2011 34
END