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Paul Vinik, PEGreenman Pedersen Inc.
Improper concrete rehabilitation gives
the whole industry a black eye.
Myth and Mystery - It is not!
Proven Technology - Cathodic protection systems mitigate corrosion.
More times than not, galanic CP it is simple:
A galv. pile jacket A bulk anode
Pile Jackets and Bulk Anodes
• A pile jacket protects the pile in the splash zone.
• A 50 lb bulk anode protects the pile below MLW.
• Additional reinforcement can be added to restore
capacity if needed.
Why Conventional Repairs Don’t Work
• Chloride compromised concrete has to be removed; ~1.2 lb/yd3
• Incipient Corrosion - spalling and corrosion occurs immediately adjacent to the repaired area usually within 3 years.
Incipient corrosion - Are you chasing your tail?
“Agencies that have successfully implemented cathodic protection technology have experienced a reduction in the frequency and cost of bridge maintenance and an increase in the service life of their bridge structures.”
CP is vastly underused
NCHRP Synthesis Report 398 - Cathodic Protection for Life Extension of Existing Reinforced Concrete Bridge Elements
CP Usage: Transportation
USE OF CATHODIC PROTECTION ON VARIOUS BRIDGE COMPONENTS: 389 US
Cathodic Protection Installed on Bridge Components
No. of Installations586
Deck 375
Superstructure 47
Caps 49
Columns 83
Piles 107
Footers 15
Note: Table based on results of Question 21 of the survey.
https://www.fhwa.dot.gov/bridge/nbi/no10/defbr17.cfm
State Bridge Counts Bridge Area (Square Meters)
All SD % All SDALABAMA 16,129 1,200 7 9,207,383 317,110ARKANSAS 12,864 765 6 6,377,740 422,629CALIFORNIA 25,657 1,603 6 29,699,888 1,737,422COLORADO 8,717 488 6 5,043,659 217,106CONNECTICUT 4,238 332 8 3,322,219 444,281DELAWARE 879 39 4 980,591 58,474FLORIDA 12,355 265 2 16,976,405 276,470GEORGIA 14,863 692 5 9,485,343 286,575HAWAII 1,135 66 6 1,320,446 19,736ILLINOIS 26,775 2,303 9 13,091,565 1,363,579INDIANA 19,291 1,435 7 8,119,288 442,819IOWA 24,215 5,067 21 8,277,421 963,382KANSAS 25,001 2,115 8 8,280,831 345,289KENTUCKY 14,280 1,110 8 6,083,768 323,503LOUISIANA 12,910 1,821 14 16,413,320 1,383,842MARYLAND 5,335 300 6 5,160,901 176,262MASSACHUSETTS 5,192 482 9 4,078,753 595,053MICHIGAN 11,180 1,175 11 6,374,178 551,179MINNESOTA 13,329 709 5 6,497,340 219,116MISSISSIPPI 17,072 2,008 12 9,382,208 467,092MISSOURI 24,487 3,086 13 10,401,265 1,004,585MONTANA 5,302 515 10 2,013,880 179,376NORTH CAROLINA 18,183 1,854 10 9,273,649 899,738NEW JERSEY 6,737 596 9 6,921,627 535,460NEW YORK 17,456 1,837 11 12,870,778 1,442,996PENNSYLVANIA 22,779 4,173 18 12,403,798 1,232,192SOUTH CAROLINA 9,341 926 10 6,796,044 454,068VIRGINIA 13,932 825 6 9,679,909 453,057RHODE ISLAND 778 181 23 799,588 185,131VERMONT 2,772 145 5 854,371 43,099WEST VIRGINIA 7,228 1,372 3,734,304 516,252
Is CP underused?
Total Structurally Deficient
(2017)
All Bridges 615,002 54,560
NHS Bridges 145,104 5,010
CP Systems 389 (2009)
Each structure has to be handled separately and a site specific corrosion assessment and mitigation plan completed.
Impressed or passive CP? 6 random piles or 8 pile bents? 5 or 50 yrs?
• Galvanic every 2 years – simple anode check and/or replacement.
• Impressed current every 6 months
• Telemetry – 24 x 7
Just like all other Transportation Infrastructure - CP systems must be maintained.
Unlike other transportation investments (except for toll plazas ), by extending service life, CP returns funds to your maintenance budget!
CP in Practice:
ICCP utilizes titanium mesh anodes and an electrical power source to control corrosion.
Where Can CP Be Used?
Wherever the reinforcement is electrically continuous and embedded in concrete. Epoxy bar?
Bridge decks, caps, beams, piles, etc.
Sacrificial CP can use either zinc, or titanium anode materials wired directly to the reinforcement.
Finished Installations
• Telemetry, solar power, on-site monitoring stations.
CP saves $$$$ - It makes cents.
• History of the Howard Frankland (HF) Bridge:
Circa 1955 - Construction begins.
Late 1980’s –rated deficient - substructure corrosion. Scheduled for replacement.
Early 1990’s – holy concrete Batman, Don’t Demo that bridge yet! ICCP pile jackets installed.
2019 - Pile jackets still functioning 35 yrs. later. The HF is in full-load service. AADT =
177,500
I like easy math!
1990 – Began installing CP systems.2024 – new structure scheduled to be completed.
$750M/75 yr. = $10M/yr.
𝟐𝟎𝟐𝟒 − 𝟏𝟗𝟗𝟎 = 𝟑𝟒 𝒚𝒓𝒔 ∗$𝟏𝟎𝑴
𝒚𝒓= $𝟑𝟒𝟎, 𝟎𝟎𝟎, 𝟎𝟎𝟎
Extended Service Life - It Makes Cents $$$$
Tampa Bay Times -https://www.tampabay.com/blogs/baybuzz/2018/08/16/contract-to-build-new-howard-frankland-bridge-is-record-814m/
Remote Monitoring: 92 channels, I-275 over Tampa Bay. Installed early 1990’s
The Story of the W. Howard Frankland Bridge
How do we keep from getting a black eye?
• FDOT – NACE – GPI: Corrosion Protection of Concrete Structures
Learning Objectives:
Cathodic protection (CP) of reinforced concrete Concrete deterioration mechanisms
Other electrochemical methods Preventative measures for new concrete
Corrosion of steel in concrete Characteristics of cement and concrete
Assessment, diagnosis, repair, and protection of concrete
https://www.nace.org/education/courses-by-program/general-corrosion/corrosion-protection-of-concrete-structures-buildings
Cathodic Protection Focal Points
Inspection: Wiring, spacing, conductivity, and grouting must be understood by inspectors. Currently no specialized training is required.
Its simple: galvanic CP requires very little long term maintenance.
It’s a great tool and It saves money!
The best view in the world is from the moral high ground
Impressed Current or Sacrificial Cathodic Protection?
Sacrificial Cathodic Protection Its simple!
1. No external power required.
2. Minimal monitoring and maintenance.
3. Can be used on high-strength pre/post-tensioned strands.
Impressed Current Cathodic Protection of Concrete
1. Requires external power.2. Caution must be used with high-strength pre- and post-tensioned strands.3. Requires regular monitoring and maintenance.
How is it done?
• Titanium mesh is the most commonly used anode material for ICCP of reinforcement in concrete.
• The titanium mesh is embedded in concrete or mortar and wired to a rectifier.
ICCP – titanium mesh
Removal and replacement of corroded reinforcement restores structural capacity
Remote Monitoring
What is Corrosion?&
What is Cathodic Protection?
• A technique used to control the corrosion of a metal by manipulating energy flow. Commonly, a higher energy or more active metal acts as an anode and is preferentially corroded/sacrificed.
• Application of an electric field to polarize the steel reinforcement such that it favors the cathodic reaction over the anodic.
• CP Prevents corrosion by converting all of the anodic (active) sites on the metal surface to cathodic (passive) sites by supplying electrical current (or free electrons) from an alternate source.
• Provides service life extensions up to 50 years.
