ROLE OF MIGRATORY CORROSION INHIBITORS FOR PROTECTING EMBEDDED

AND EXPOSED STEELPRESENTED AT

MEGA RUST 2015NAVAL CORROSION CONFERENCE

June 23 to 25, 2015NEWPORT NEWS, VA

PRESENTED BYROBERT WALDE

SURTREAT HOLDING, LLC

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

Reinforcing Steel CorrosionReinforcing 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++ + 2e- Anodic cell

H2O + O 2OH- Cathodic cell

Feo + H2O + O Fe(OH)2 + 2e- Equilibrium cell

Fe2O3 Expands causing concrete delamination and spalling

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

Reinforced Concrete Micro Structure

METHODS FOR UTILIZING MIGRATORY CORROSION INHIBITORS

SURFACE APPLIED ON REINFORCED CONCRETE Inorganic and organic types usedADDED TO CONCRETE AND SHOTCRETE MIX Inorganic and organic types usedDIRECT APPLICATION ON STEEL Organic type dissolved in oil INDIRECT APPLICATION ON STEEL Organic types placed in enclosed space or on

packagingADDITION TO STEEL SURFACE COATING Organic type added to coating formulation

APPLICATION OF MIGRATORY CORROSION INHIBITOR ON BRIDGE DECK

CORROSION MEASUREMENT METHODSELECTRO-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 C876-09 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 D1654 SCORE ON

SCALE OF 10 TO 1 DEGREE OF SURFACE RUST ASTM D610 SCORE ON SCALE OF 10 TO 1

GALVAPLUSE CORROSION RATE MEASUREMENT

NASA/KSC JOINT R&D EVALUATION OF TWO NEW MIGRATORY REBAR CORROSION INHIBITORS IN 1996MIGRATORY 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

NASA/KSC INORGANIC MIGRATORY CORROSION INHIBITOR PERFORMANCE MEASUREMENT

NASA/KSC ORGANIC VAPOR PHASE MIGRATORY CORROSION INHIBITOR PERFORMANCE MEASUREMENT

CORPS OF ENGINEERS OKINAWA BRIDGE AND GIRDER RESTORATION PROJECT USING SURFACE APPLIED MIGRATORY CORROSION INHIBITORS

STRUCTURE TYPESFuel depot patrol bridgesWarehouse ring girders

AGE OF STRUCTURESBuilt in the 1950’s

REBAR CORROSION CONDITIONCarbonation front has reached the rebar levelConcrete spalling exposed rusty rebar

SURFACE APPLIED MIGRATORY CORROSION INHIBITORS APPLIED Inorganic/anodic /silicate typeOrganic/anodic/cathodic/aminecarboxylate type Application Rates 100SF/gal

14

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

Initial Conditions

1 ft.

15

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.

Initial Conditions

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 2007 JULY 2007 JULY 2010

MEDIAN CORROSION 41 6 5

RATE

AVERAGE CORROSION 61 23 14

RATE

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 2007 JULY 2007 JULY 2010

MEDIAN CORROSION 30 8 7

RATE

AVERAGE CORROSION 37 13 7

RATE

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/GallonIonic Phase Inhibitor Applied At 200 Ft²/Gallon6.5 Months Later Corrosion Current Measured At Some

26 Points on DeckCorrosion Current Converted To Corrosion Rate1 Micro Amps Per Cm² = 11.6 Micrometers of Rebar Steel

Loss Per YearCorrosion Rates Displayed on Bar Graph

REBAR CORROSION RATE BEFORE AND AFTER INHIBITOR APPLICATION

CALCULATION OF STRUCTURE LIFETIME BASED ON REBAR CORROSION RATE

Calculation Equation And AssumptionsAssumptions 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

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 InhibitorsT= D/2x10¯³ x R(t) x K

Before application T = 4mm/2x10¯³ x 100 x 2.5 = 8 yearsAfter application T = 4mm/2x10¯³ x 28 x 1.0 = 72 years

PAINT PLUS MIGRATORY CORROSION INHIBITORPAINT TYPE2 Part Epoxy Polyamide Primer, Formula 150,Type III Conformance:MIL-DTL-24441/20

MIGRATORY CORROSION INHIBITORType: Amine-carboxylate added to part AConcentration: 2.5weight percent of dry film solids

APPLICATIONSpray applied on new and pre-corroded ASTM A1008 carbon steel panels

abraded with black beauty

PAINT PLUS MIGRATORY CORROSION INHIBITOR

PERFORMANCE EVALUATIONAPPLICATION2 To 3 Mil Film On Abraded White And Corroded Steel Panels

EXPOSURE500 Hours In Salt Fog Chamber Per ASTM B117

PERFORMANCE MEASUREMENTSFilm 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

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 4B 3 4

With VCI 5B 6 8

COMPARISON OF PERFORMANCE WITH AND WITHOUT MIGRATORY INHIBITOR ADDED TO PAINT

APPLIED ON WHITE STEEL PANELSVCI TYPE CONDITION ADHESION CREEP DEGREE RUST

Without VCI 5B 5.3 3.0

With VCI Added 4B 6.3 8.8

* average of 4 panels

BENEFITS OF PAINT PLUS MIGRATORY CORROSION INHIBITORCAN BE APPLIED ON RUST COVERED STEELWILL 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

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.

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)