silanes jh clients.pdf

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]




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





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


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




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




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


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

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