1. NAVAL CORROSION CONFERENCE
ROLE OF MIGRATORY CORROSION INHIBITORS FOR PROTECTING EMBEDDED AND EXPOSED STEEL
PRESENTED AT
MEGA RUST 2015
NAVAL CORROSION CONFERENCE
June 23 to 25, 2015
NEWPORT NEWS, VA
PRESENTED BY
ROBERT WALDE
SURTREAT HOLDING, LLC

2. Cement Chemistry
Porosity –Cement Phase 20% (W/C 0.5) – Penetration of water, air (oxygen and carbon dioxide), Chlorides (CIˉ), other. Alkalinity – pH 13 – Hydroxyl ions (OHˉ) – Inhibit steel corrosion. Carbonation - Reduce pH – Ca(OH)2 + CO2 → CaCO3+H2O pH – 13 to pH – 8

3. Reinforcing Steel Corrosion
Reinforcing Steel Corrosion – Major Cause of Concrete Structure Failure
Steel Corrosion Mechanism and Impact
Electrochemical oxidation process
Inhibited by cement alkalinity and cover
Accelerated by cement chloride, air and moisture content
Types of corrosion
Micro cell – same rebar
Macro cell – different rebar
Uniform – exposed steel
Pitting – most common
Feo Fe e- Anodic cell
H2O + O OH Cathodic cell
Feo + H2O + O Fe(OH)2 + 2e Equilibrium cell
Fe2O Expands causing concrete delamination and spalling

4. TYPES AND MECHANISMS OF MIGRATORY CORROSION INHIBITORS
INORGANIC TYPE
MIGRATE IN THE IONIC PHASE
FUNCTION AT THE ANODIC CORROSION SITE
CHEMICAL TYPES ARE SILICATES AND NITRITES
ORGANIC TYPE
MIGRATE IN THE VAPOR PHASE
FUNCTION AT BOTH ANODIC AND CATHODIC SITES
CHEMICAL TYPES ARE AMINE CARBOXYLATES AND AMINE ALCOHOLS

5. Reinforced Concrete Micro Structure

6. METHODS FOR UTILIZING MIGRATORY CORROSION INHIBITORS
SURFACE APPLIED ON REINFORCED CONCRETE
Inorganic and organic types used
ADDED TO CONCRETE AND SHOTCRETE MIX
DIRECT APPLICATION ON STEEL
Organic type dissolved in oil
INDIRECT APPLICATION ON STEEL
Organic types placed in enclosed space or on packaging
ADDITION TO STEEL SURFACE COATING
Organic type added to coating formulation

7. APPLICATION OF MIGRATORY CORROSION INHIBITOR ON BRIDGE DECK

8. CORROSION MEASUREMENT METHODS
ELECTRO-PHYSICAL METHODS
DIRECT CORROSION CURRENT FLOW FROM ANODE TO CATHODE
ASTM G109 MEASURES MACRO-CELL CURRENT
INDIRECT MEASUREMENT OF CORROSION CURRENT BY POLARIZATION RESISTANCE ASTM G 59
Icr =Vp/Pr
GALVAPLUSE INSTRUMENT
HALF-CELL POTENTIAL
ASTM C MEASURES POTENTIAL FOR CORROSION OR DRIVING FORCE FOR CORROSION IF CONDITIONS FOR CORROSION EXIST.
DIRECT OBSERVATION OF PROTECTIVE COATING SURFACES
DEGREE OF CREEP FROM X SCRIBED AREA ASTM D SCORE ON SCALE OF 10 TO 1
DEGREE OF SURFACE RUST ASTM D SCORE ON SCALE OF 10 TO 1

9. GALVAPLUSE CORROSION RATE MEASUREMENT

10. NASA/KSC JOINT R&D EVALUATION OF TWO NEW MIGRATORY REBAR CORROSION INHIBITORS IN 1996
MIGRATORY CORROSION INHIBITORS EVALUATED
Inorganic Water Soluble Anodic Type Applied at 100SF/Gal
Organic Alcohol Soluble Anodic/Cathodic Type Applied at 100SF/Gal
TEST METHOD USED
Macro-cell Designed To Measure Half-cell Potential and Corrosion Current
Design And Method Similar To ASTM G109
Chloride Activated Rebar (Anodic State) At 1 and 2 Inches From Surface
Cathodic State Rebar 5 Inches From Surface
Half-cell Measured Through Ports In Test Block

11. NASA/KSC INORGANIC MIGRATORY CORROSION INHIBITOR PERFORMANCE MEASUREMENT

12. NASA/KSC ORGANIC VAPOR PHASE MIGRATORY CORROSION INHIBITOR PERFORMANCE MEASUREMENT

13. CORPS OF ENGINEERS OKINAWA BRIDGE AND GIRDER RESTORATION PROJECT USING SURFACE APPLIED MIGRATORY CORROSION INHIBITORS
STRUCTURE TYPES
Fuel depot patrol bridges
Warehouse ring girders
AGE OF STRUCTURES
Built in the 1950’s
REBAR CORROSION CONDITION
Carbonation front has reached the rebar level
Concrete spalling exposed rusty rebar
SURFACE APPLIED MIGRATORY CORROSION INHIBITORS APPLIED
Inorganic/anodic /silicate type
Organic/anodic/cathodic/aminecarboxylate type
Application Rates 100SF/gal

14. Initial Conditions
1 ft.
Structures were experiencing significant rebar corrosion prior to rehabilitation. Corrosion appeared to be due to carbonation of the concrete rather than chloride-induced corrosion

15. Initial Conditions Ring girder of warehouse at Naha Port
Girder shows signs of deterioration due to rebar corrosion and general breakdown of the concrete cement structure. Spalling, efflorescence, delamination, rust stains and other common signs of concrete failure.

16. CORROSION RATE MEASUREMENTS ON REINFORCED CONCRETE BEAM BEFORE AND AFTER APPLICATION OF MIGRATORY CORROSION SYSTEM ON CONCRETE SURFACE
MIGRATORY CORROSION SYSTEMS
Organic, Duel Function, Vapor Phase Inhibitor Applied First At 100SF/Gal Of Formulated Product
Anodic Ionic Phase Migratory Inhibitor Applied Second At 100SF/Gal Of Formulated Product
CORROSION RATE IN MICROMETERS OF STEEL LOST PER YEAR BY CONVERSION OF CORROSION CURRENT IN MICROAMPS PER CM2
BEFORE APPLICATION AFTER APPLICATION
JANUARY JULY JULY 2010
MEDIAN CORROSION
RATE
AVERAGE CORROSION

17. CORROSION RATE MEASUREMENTS ON REINFORCED CONCRETE BRIDGE BEFORE AND AFTER APPLICATION OF MIGRATORY CORROSION SYSTEM ON CONCRETE SURFACE
MIGRATORY CORROSION SYSTEMS
Organic, Duel Function, Vapor Phase Inhibitor Applied First At 100SF/Gal Of Formulated Product
Anodic Ionic Phase Migratory Inhibitor Applied Second At 100SF/Gal Of Formulated Product
CORROSION RATE IN MICROMETERS OF STEEL LOST PER YEAR BY CONVERSION OF CORROSION CURRENT IN MICROAMPS PER CM2
BEFORE APPLICATION AFTER APPLICATION
JANUARY JULY JULY 2010
MEDIAN CORROSION
RATE
AVERAGE CORROSION

18. APPLICATION OF MIGRATORY CORROSION INHIBITORS ON PARKING GARAGE DECK
Corrosion Current Measured on 26 Points Over Rebar Mat Before And After Application of Inhibitors
Vapor Phase Inhibitor Applied At 150 Ft²/Gallon
Ionic Phase Inhibitor Applied At 200 Ft²/Gallon
6.5 Months Later Corrosion Current Measured At Some 26 Points on Deck
Corrosion Current Converted To Corrosion Rate
1 Micro Amps Per Cm² = 11.6 Micrometers of Rebar Steel Loss Per Year
Corrosion Rates Displayed on Bar Graph

19. REBAR CORROSION RATE BEFORE AND AFTER INHIBITOR APPLICATION

20. CALCULATION OF STRUCTURE LIFETIME BASED ON REBAR CORROSION RATE
Calculation Equation And Assumptions
Assumptions
Rebar diameter at time zero. Assume to be 20mm
Percent loss in rebar diameter to reach critical structural point. Assume to be 20% or 4mm
Equations
With respect to diameter D = 2x10¯³ x R(t) x K x T
With respect to time T = D/2x10¯³ x R(t) x K
D = the loss in rebar diameter over time T
T = Number of years in time for loss of the measured rebar diameter
R(t) = The average corrosion rate at time zero in terms of micrometers of steel lost per year
K = A factor multiplying the average corrosion rate it account for the presence of corrosion hot spots

21. CALCULATION OF TIME TO REACH CRITICAL STRUCTURAL POINT
Corrosion Rate Measurements Before and After Application of Migratory Corrosion Inhibitors
Average corrosion rate before application = 100uM/Yr.
Average corrected corrosion rate after application = 28uM/Yr.
Average corrosion rate before application for 5 highest point = 250uM/Yr.
Ratio of average rate before application and 5 hot spot points = 2.5 K
Calculation of Time in Years To Reach From Time Zero To Reach The Critical Structural Point Before And After Application of Migratory Corrosion Inhibitors
T= D/2x10¯³ x R(t) x K
Before application T = 4mm/2x10¯³ x 100 x 2.5 = 8 years
After application T = 4mm/2x10¯³ x 28 x 1.0 = 72 years

22. PAINT PLUS MIGRATORY CORROSION INHIBITOR
PAINT TYPE
2 Part Epoxy Polyamide Primer, Formula 150,Type III
Conformance:MIL-DTL-24441/20
MIGRATORY CORROSION INHIBITOR
Type: Amine-carboxylate added to part A
Concentration: 2.5weight percent of dry film solids
APPLICATION
Spray applied on new and pre-corroded ASTM A1008 carbon steel panels abraded with black beauty

23. PAINT PLUS MIGRATORY CORROSION INHIBITOR
PERFORMANCE EVALUATION
APPLICATION
2 To 3 Mil Film On Abraded White And Corroded Steel Panels
EXPOSURE
500 Hours In Salt Fog Chamber Per ASTM B117
PERFORMANCE MEASUREMENTS
Film Adhesion Per ASTM D3359 On Scale 0 To 5
Creep From X Score Per ASTM D1654 On Scale Of 0 To 10 (10 No Creep)
Degree Of Rust On Smooth Side Per ASTM D610 On Scale Of 0 To10

24. APPLIED ON CORRODED STEEL PANELS
COMPARISON OF PERFORMANCE WITH AND WITHOUT MIGRATORY INHIBITOR ADDED TO PAINT
APPLIED ON CORRODED STEEL PANELS
VCI TYPE CONDITION ADHESION CREEP DEGREE OF RUST
Without VCI B
With VCI B

25. APPLIED ON WHITE STEEL PANELS
COMPARISON OF PERFORMANCE WITH AND WITHOUT MIGRATORY INHIBITOR ADDED TO PAINT
APPLIED ON WHITE STEEL PANELS
VCI TYPE CONDITION ADHESION CREEP DEGREE RUST
Without VCI B
With VCI Added B
* average of 4 panels

26. BENEFITS OF PAINT PLUS MIGRATORY CORROSION INHIBITOR
CAN BE APPLIED ON RUST COVERED STEEL
WILL MIGRATE THROUGH RUST TO WHITE METAL SURFACE AND TO HARD TO COAT RECESSED AREAS
CAN PERFORM SPOT COATING MAINTENANCE WITHOUT NEED FOR SURFACE PREPARATION TO WHITE METAL
USE AS PRIMER COAT FOR FINAL FINISH COAT

27. MIGRATORY CORROSION INHIBITORS A TOOL FOR PRESERVATION OF BRIDGES
APPLY ON EXISTING REINFORCED CONCRETE STRUCTURES EXPERIENCING REBAR CORROSION TO EXTEND LIFE.
ADD TO CONCRETE MIX OR ON SURFACE OF NEW STRUCTURES TO INHIBIT DAMAGE FROM FUTURE CORROSION CONDITIONS.
APPLY PAINT WITH MIGRATORY CORROSION INHIBITORS ON NEW ANND CORRODED STEEL STRUCTURES AND COMPONENTS.

28. CREDITS FOR SUPPORT OF MIGRATORY CORROSION INHIBITOR PROJECTS
JOE CURRAN, NASA CORROSION LABORATORY KENNEDY SPACE CENTER (Original Evaluation Of Migratory Corrosion Inhibitors)
DAVID STEPHENSON, ASHOK KUMAR, US ARMY CORPS OF ENGINEERS, ENGINEER RESEARCH AND DEVELOPMENT CENTER (Project On Bridges Warehouse Ring Girders in Okinawa)
RICH LAMPO , US ARMY CORPS OF ENGINEERS, ENGINEER RESEARCH AND DEVELOPMENT CENTER ( Project on evaluation of addition of vapor phase corrosion inhibitors to steel primer)