Pile Protection for Coastal Structures

Pile Protection for Coastal Structures

CONCRETE PRESERVATION ALLIANCE

The Concrete Preservation Alliance is a growing coalition of organizations committed to advancing best practices in the field of concrete preservation and infrastructure renewal.

Working together to promote education and awareness of concrete repair industry standards, new and innovative corrosion prevention technologies and sustainable construction practices.

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OUR MEMBERS

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Jason Chodachek, NACE CP Technician

Jason Chodachek is a Marine Specialist with Vector Corrosion Technologies and a NACE Cathodic Protection Technician.

Jason received his associate's degree in computer engineering then started his career in the concrete repair industry. He has over 25 years of experience in the restoration and protection of reinforced concrete structures.

Jason has worked extensively in areas related to corrosion of reinforcing steel, cathodic protection installation, concrete condition assessments, and concrete repair.

Pile Protection for Coastal Bridges

• Extending the life of concrete and steel piles in fresh, brackish and saltwater

Outline

Corrosion and Concrete

Exposure Conditions

Types of CP Jackets

Comparison of CP Jackets

Typical Installations

Steel Sheet Pile CP

Why Does Steel Corrode? Corrosion and Energy

What is Concrete?

• Hard Sponge (very porous)

• Great in Compression• Poor in Tension• Requires Reinforcement

• Highly Alkaline (pH 13+)

Why Concrete Protects Against Corrosion

“Passivation” (a protective layer)

Passivation = A protective layer that holds energy in, prevents steel from corroding

Good quality concrete forms a protective passivation layer over the steel.

Why ConcreteProtects Against Corrosion

Results in the passivation layerbreaking down.

2 Main Disruptions to Passivation:• Carbon Dioxide (CO2)• Chlorides (salts)

Main Source of Corrosion

• Caused by chlorides breaking up passive oxide layer

• Sources of chlorides: • Marine Environments• De-icing Salts (NaCl,

CaCl2)• Chemical Plant

Environment• Cast-in Chlorides

• Vicious Circle: Chlorides are never consumed Salt is the main source for corrosion

Reinforced Concrete Pile Corrosion

CORROSION OF REINFORCED CONCRETE PILES

History of Pile Protection – Grout Filled Stay In Place Forms

• Oversized fabric / FRP forms placed around a distressed concrete pile.

• Secured at the bottom and closed with a heavy zipper.

• Filled with concrete

• Does not address ongoing corrosion of the reinforcing steel.

• Makes visual inspection of continued corrosion impossible.

Installed Bag Jacket Bag Jacket being removed

History of Pile Protection - FRP Epoxy Jackets

• FRP jackets placed around the area of deterioration on a pile and filled with an epoxy grout.

• Future corrosion under the jacketing is concealed.

• Corrosion continues under the filled jacket

• The jacket conceals damage from future visual inspections.

Epoxy Filled FRP Jacket Failed Epoxy Filled FRP Jacket

History of Pile Protection

• 1990’s it was documented that cement grout and epoxy grout jacketing repairs was ineffective for chloride contaminated piles.

• Corrosion continued and the jacketing concealed the pile damage from detection by visual inspection.

• 1998 Florida Department of Transportation research concluded that only jacketing that included cathodic protection be permitted.

• 1999 – Virginia Transportation Research Council found that jacketing alone is inadequate protection and should be supplemented with cathodic protection. Failed FRP Jackets Without Cathodic Protection

Pile Exposure Conditions

Submerged is the underwater section of piles. Thesubmerged section is less frequently affected bycorrosion damage due to low levels of dissolvedoxygen which is necessary at the cathodic sites tofacilitate the reduction reaction (O2 + 2H2O + 4e- →4OH-).

Submerged

Tidal Zone


Tidal Zone - is regularly saturated by the rise and fall ofsea levels caused by gravitational forces exerted by themoon, sun and the rotation of the earth. This section is atrisk due to increased levels of chloride and oxygen butcorrosion may be limited due to continual saturation.

Splash Zone


Zone 3 (Splash) is occasionally wetted and is verycorrosive due to high levels of chloride and oxygen.


Atmospheric

Zone 4 (Atmospheric) is the dry section of a pile that isexposed to airborne chloride deposition on the surface of theconcrete. After sufficient quantities of chloride diffuse to thelevel of the reinforcing steel, corrosion is initiated eventuallyleading to concrete degradation.

Submerged

Tidal Zone

Splash Zone


Atmospheric

All conditions can be corrosive!

Corrosion Protection Using Dissimilar Metals

ZincAnode

Reinforcing SteelCathodeGalvanic Cell

Zinc Activation

• Salt activates zinc by lowering the electrical resistance of water.

• Zinc oxide occurs from a chemical process called oxidation in which zinc atoms lose electrons, forming ions.

Zinc oxidizes when submerged in seawater

Tidal Zone Protection of Concrete Piles

Tidal Zone

Submerged

Bulk Anode – Submerged Zone

Zinc Mesh Jacket Galvashield® Tidal Jacket

Junction Box

Stay In Place FRP Form with Zinc MeshTidal Protection

Zinc Mesh Jacket Installation



Corrosion Rate of Zinc vs pH

Lower portions receive most of the cathodic current because of the continuous wetting with saltwater.

Dry portions of the jacket receive limited or no protection from lack of saltwater and direct contact with low pH concrete. Zinc Mesh passivates reducing galvanic current.

Zinc Mesh Jacket Limitations

Zinc Passivates

Zinc passivates with direct contact with concrete. Anode current drops greatly

without the wetting of seawater.

Improved Tidal / Splash Zone Protection Galvashield® Tidal Plus Jacket

Splash Zone

Tidal Jacket Improvements

What can be done to increase the zinc activation in the splash / tidal zone?

• Increase the zinc anode exposure to the saltwater

• Increase wet zone• Prevent the zinc from passivating• Increased performance / utilization

WET ZONE

DRY ZONE

Galvashield® Tidal Plus Jacket

Bulk Anode – Submerged Zone

Wicking AnodeTidal & Splash Zone PVC / FRP Form


WET ZONE

Saltwater wicks up the wicking fabric tail and completely saturates the zinc

anode inside the wicking fabric.

Fabric isolates the zinc from being passivated by the concrete mortar.

IncreasedCapillaryAction

Wicking TailWicking Tail

Tidal Plus Jacket – Increase Current Output

Cast solid zinc anode.

Wicking Fabric for increased saltwater capillary action.

Concrete

Anode wires cast Insidefull length of anode. Reliable connection for the entire life.

Protective barrier between zinc and low pH concrete.

Zinc passivates with direct contact with concrete. Stopping the flow of galvanic

current at a pH of 13 and below.


Tidal Plus JacketLife Cycle Design Improvements

Standard zinc density of 1.6lbs zinc / sqft (7.8kg / sqm). One size fits all. No adjustments can be made for longer service life.

Tidal Mesh Jacket Tidal Plus Wicking JacketDesigned based upon service life requirements. Anode spacing can be adjusted to meet service life requirements.


Stay In Place PVC forms and wicking anodes Wicking anodes attached and form installed


Bracing installed and secured. Jacket pumped with grout

Atmospheric

Dry Atmospheric – No SaltwaterGalvashield® DAS Activated Jacket

Saltwater is available to activate zinc.

NO -Saltwater is

available

Zinc Activation

• Salt causes zinc to oxidize.

• Zinc oxidizes in both a low and high pH environment.

• Steel is protected in a high pH environment

• Use a high pH environment to keep the zinc in an active state, while not being harmful to reinforcing steel.


Self-Activated Galvashield® DAS Jacket

• Saltwater NOTrequired!

• Alkali Activated Anodes used to protect piles and columns in:

• Saltwater • Brackish water• Fresh water and• Dry land applications.

• Use appropriate bulk anode for underwater protection when required.

Optional Junction Box

Anode encased in (high pH)Alkali Activated mortar

Stay In Place Form

SALTWATER NOT REQUIRED

Self-Activated Galvashield® DAS JacketFlorida DOT – Lake Worth

• 40 Galvashield DAS Jackets• Installed in the atmospheric zone• Alkali Activated due to the lack of

direct wetting of the saltwater


• Delaminated concrete was removed

• Continuity groove created


• Steel was cleaned• Reinforcing steel

checked for continuity


• Alkali Activated Galvashield DAS anodes pre-installed in onto FRP jackets


• Jackets placed around the column

• All anode and cathode connection are made

• Jacket is braced for pumping


• Concrete grout was pumped into the jackets with pumping ports spaced evenly around the jacket.


• Energizing of the jackets competed

• 45 degree chamfer applied to the top of the jacket.

Galvanic Jacket System OverviewModels and Recommended Use

Pumping PortsOptions

Integrated Pumping TubesPumped from the top using a “T” connector

Pumping PortsDivers used to move concrete hose from one pumping port to another

Concrete hoseAttached to port at bottom of the jacket.

Galvashield® Bulk AnodesSheet Pile Protection

Deteriorated Uncoated Sheet Piling Failed Coating


3 ZonesAtmospheric

Tidal

Submerged


Submerged

Submerged

Submerged has limited oxygen and is in direct contact with saltwater at all times. The seawater is a very good electrolyte.


Submerged

Submerged

Bulk aluminum anodes are directlyattached to the sheet pile wall. Theseawater acts as an electrolyte andgalvanic current is distributedthroughout the submerged zone.

Aluminum Bulk Anodes

Galvashield® Bulk AnodesSheet Pile ProtectionTidal & Atmospheric

Atmospheric

Tidal

These two zones have plenty of oxygen and moisture available to aid in the corrosion process. Bulk anodes cannot be used because of the lack of seawater.


Atmospheric

Tidal

Alkali Activated DAS anodes can be directly attached to the tidal and atmospheric locations of the sheet pile.

Tidal & Atmospheric


Atmospheric

Tidal

These Alkali Activated DAS anodesneed to be encased in an electrolyte.A concrete cap is added to the top ofthe sheet pile. This provides anenvironment for the anodes tofunction properly and provides addedprotection.

Tidal & Atmospheric


Bulk Aluminum Anode Bulk Aluminum Anode Magnesium Anode Coke Breeze BagSoil Side of Sheet Pile Wall

TimelineCathodic Protection Jackets

Before Cathodic ProtectionFabric and FRP filled concrete jackets and epoxy grout filled FRP jackets. Did notaddress the ongoing corrosion and concealed visual signs of corrosion behind the jacket.


1990Zinc Mesh

Jackets for tidal zone protection

1990Zinc Mesh


The original zinc mesh jacket was developed in the early 1990’s


1990Zinc Mesh


1999Alkali Activated discrete anodes for patch repairs



The Galvashield® XP was the first Alkali Activated anodeintroduced to the concrete repair market. This original XP anodehas evolved into multiple sizes and increased performance.


1990Zinc Mesh



2004Alkali Activated

Jackets


With the success of the Galvashield® XP anodes this same technologywas used to create a Alkali Activated Galvashield® DAS Jacket system.This Activated Jacket filled a void where the Tidal jacket was ineffective.The Galvashield® DAS Jacket was able to protect concrete reinforcedpiles in Fresh / Brackish water and Dry environments without thepresence of saltwater.



Jackets

1990Zinc Mesh



2015Wicking Fabric Jackets for

Extended Splash / Tidal zone protection



Jackets

The Galvashield® Tidal Plus Jacket improved on the original TidalJacket, increasing the protection to higher elevations outside ofthe tidal zone. The galvanic current and performance wassignificantly increased by isolating the zinc from concrete mortarwhile keeping the zinc fully saturated with saltwater.




1990Zinc Mesh







Jackets

QUESTIONS?

Contact Jason

Jason ChodachekBusiness Development ManagerMarine SpecialistVector Corrosion TechnologiesMelbourne, FL

Office: (813) [email protected]

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Pile Protection for Coastal Structures