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TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
One-Coat Systems Applicable to Steel Bridge Structures
Coatings & Corrosion LaboratoryOffice of Infrastructure R & D
Turner-Fairbank Highway Research CenterFederal Highway Administration
McLean, VA 22101
TRB 2009
One-Coat Systems Applicable to Steel Bridge Structures
Coatings & Corrosion LaboratoryOffice of Infrastructure R & D
Turner-Fairbank Highway Research CenterFederal Highway Administration
McLean, VA 22101
TRB 2009
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Coating SystemsCoating Systems1. 3-coat control (Organic Zn + Epoxy + Polyurethane)2. 2-coat control (MCU-Zn + Polyaspartic)3. Polyaspartic (ASP)4. Epoxy Mastic (EM)5. Calcium Sulfonate Alkyd (CSA)6. Glass Flake Polyester (GFP)7. High Build Acrylic (HBAC)8. Waterborne Epoxy (WBEP)9. Polysiloxane (SLX)10. Urethane Mastic (UM)
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Test PanelsTest Panels
Unscribed Scribed Unscribed Scribed Unscribed Scribed
1 3-coat 3 3 3 3 6 6 24
2 2-coat 3 3 3 3 6 6 24
3 ASP 3 3 3 3 6 6 24
4 EM 3 3 3 3 6 6 24
5 CSA 3 3 3 3 6 6 24
6 GFP 3 3 6**
7 HBAC 3 3 3 3 6 6 24
8 WBEP 3 3 3 3 6 6 24
9 SLX 3 3 3 3 6 6 24
10 UM 3 3 3 3 6 6 24
30 30 27 27 54 54 222
Outdoor Weathering (6 x 12 in.)*Total
** Only laboratory test panels were prepared due to late arrival of test material.
Total
* The test panels will be exposed to natural weathering at Turner-Fairbank facility with periodic salt spray.
System No. System ID
Laboratory (4 x 6 in.) Sea Isle (4 x 6 in.)
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Accelerated Laboratory TestingAccelerated Laboratory Testing1. Freeze Cycle for 24 hours at -23 oC (-10 oF)
2. UV/Condensation Cycle for 168 hours:• 4-hour UV at 60 oC (140 oF)• 4-hour condensation at 40 oC (104 oF)
3. Alternating Salt-Fog Cycle for 168 hours:• 1-hour wet with 0.35% (NH4)2SO4 plus 0.05% NaCl solution at
ambient temperature• 1-hour dry at 35 oC (95 oF)
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Accelerated Laboratory Testing - ContinuedAccelerated Laboratory Testing - Continued
● Test Hours per Cycle: 360 Hours● Total Test Cycles: 19● Total Test Hours: 6,840 Hours● Performance Evaluation After Each Test Cycle
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Outdoor Exposure at TFHRCOutdoor Exposure at TFHRC
• Periodic performance evaluation every six months
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Outdoor Exposure at Sea Isle City, NJOutdoor Exposure at Sea Isle City, NJ
• Periodic performance evaluation every six months
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Periodic Performance EvaluationPeriodic Performance Evaluation1. Surface Defects and Failures ( By holiday detector and digital
microscope )2. Coating Impedance Properties3. Rust Creepage (ASTM D7087)4. Photographic Documentation5. Change of Gloss *
* For outdoor exposed panels only
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
PhotomicrographsPhotomicrographs
(2-coat system, 20X) (3-coat system, 20X)
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Rust Creepage Growth (Lab Testing)Rust Creepage Growth (Lab Testing)
0
5
10
15
20
25
30
35
40
0 720 1440 2160 2880 3600 4320 5040 5760 6480 7200
Duration (hour)
Cre
epag
e (m
m)
3-coat2-coatASPEMCSAGFPHBACWBEPSLXUM
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Rust Creepage Growth (Sea Isle City)Rust Creepage Growth (Sea Isle City)
0
5
10
15
20
25
30
35
40
0 4320 8640 12960 17280
Duration (hour)
Cre
epag
e (m
m)
3-coat2-coatASPEMCSAHBACWBEPSLXUM
0.0
0.5
1.0
1.5
12240 129600.0
0.5
1.0
1.5
12240 129600.0
0.5
1.0
1.5
122400.0
0.5
1.0
1.5
12240 12960
0
5
10
15
20
25
30
35
40
0 4320 8640 12960 17280
Duration (hour)
Cre
epag
e (m
m)
3-coat2-coatASPEMCSAHBACWBEPSLXUM
0.0
0.5
1.0
1.5
12240 129600.0
0.5
1.0
1.5
12240 129600.0
0.5
1.0
1.5
122400.0
0.5
1.0
1.5
12240 12960
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
3-Coat System (Control)3-Coat System (Control)
0 2,160 4,320 6,840
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
CSACSA
0 2,160 4,320 6,840
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
GFPGFP
0 2,160 4,320 6,840
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
EMEM
0 2,160 4,320 6,840
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
WBEPWBEP
0 2,160 4,320 6,840
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
UMUM
0 2,160 4,320 6,840
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Findings Findings
1. Two control coating systems (3-coat and 2-coat) had a dry film thickness (DFT) of approximately 13 mils and a pencil scratch hardness of HB.
2. The 3-coat demonstrated very good performance in almost all aspects and slightly better than the 2-coat.
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Findings - Continued Findings - Continued 3. With regard to initial DFT, pencil scratch hardness, and
adhesion properties, the eight one-coat systems varied significantly compared to those of the controls.
4. Four one-coat systems (ASP, WBEP, SLX, and UM) had either higher adhesion strength or thicker DFT compared to the controls, but their performance in terms of defect development, rust creepage, and rate of physical deterioration was far inferior to the rest.
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Findings - Continued Findings - Continued 5. The fifth one-coat system, HBAC, had a DFT of 10.4
mils with a very soft pencil scratch hardness (6B) and showed mixed results with a relatively low number of coating defects, moderate rust creepage resistance, and good physical appearance.
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Findings - Continued Findings - Continued 6. To date, CSA has been the best performer despite its
softness and very weak adhesion strength. 7. GFP is also an excellent coating system and is the 2nd
best in the overall performance rating. These two one-coat systems outperformed the controls.
8. Performance of EM was comparable to those of the control systems.
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
100-Year Life Coating Systems
Coatings & Corrosion LaboratoryOffice of Infrastructure R & D
Turner-Fairbank Highway Research CenterFederal Highway Administration
McLean, VA 22101
TRB 2009
100-Year Life Coating Systems
Coatings & Corrosion LaboratoryOffice of Infrastructure R & D
Turner-Fairbank Highway Research CenterFederal Highway Administration
McLean, VA 22101
TRB 2009
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
BackgroundBackground1. This is a Congress mandated study under the HPS
program.2. Main objective is to identify and evaluate coating
materials that can provide 100 years of maintenance-free service life for steel bridge structures.
3. This study started in November 2008 and will be carried out for 36 months.
4. Some types of weathering steel will be also tested.
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Coating Systems SelectedCoating Systems SelectedSystem
Number Category Generic Coating Name
1 Control - Conventional 3-coat Shop System IOZ / Epoxy / Aliphatic Polyurethane
2 Control -3-coat OZ Shop System Zn-rich Epoxy / Epoxy / Aliphatic Polyurethane
3 3-coat Fluoro-Topcoat System MCU Zn / Epoxy / Fluorourethane
4 2-coat Fast Dry Coating Zn-rich Epoxy / Aliphatic Polyurethane
5 2-coat Polysiloxane Inorganic Zinc / Polysiloxane
6 Metallizing (conventional) + Topcoat Thermal Sprayed Zinc / Linear Epoxy
7 Organic Zinc Rich Epoxy (Zinc Flake)/Linear Epoxy Experimental Primer / Topcoat
8 Calcium Sulfonate Alkyd HR Single Coat CSA
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Type 1 Test Panels (4 x 6 in.)Type 1 Test Panels (4 x 6 in.)
Accelerated Lab Test
Outdoor Weathering Test
Destructive Test (Ahesion)
Control 2 10 10 4 24
Others 6 30 30 12 72
Subtotal 8 40 40 16 96
Number of Test PanelsNumber of
Coating Systems
CategoryTotal Number
of Test Panels
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Type 2 Test Panels (18 x 18 in.)Type 2 Test Panels (18 x 18 in.)
Outdoor Weathering Test (without salt
spray)
Outdoor Weathering Test (with salt spray)
Outdoor Weathering Test
(Golden Gate Bridge)
Control 2 2 2 2 6
Others 6 6 6 6 18
Subtotal 8 8 8 8 24
Number of Test PanelsNumber of
Coating Systems
CategoryTotal Number
of Test Panels
[A-A] [B-B]
18 in.
18 in.
B
B
A
A
StripeCoat
Weld
Normal Test Area with Attachments
(No Cl-, target anchor profile,
target DFT)
Poorly Prepared Area (4 x 8 in.)(Cl-, less anchor profile, 20% less DFT)
20% Thicker DFTArea (4 x 8 in.)(No Cl-, target anchor profile)
Tee
AngleAngle
Bolt & nut Angle
FHWA Outdoor Large-Scale Weathering Test Panel for 100-Year Coating Study
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Test PanelsTest Panels
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
TestsTests1. Coating Thickness2. Gloss3. Color4. Pencil Scratch Hardness5. Infrared Spectrometry6. Adhesion 7. EIS
8. Rust Creepage9. Surface Examination
(Defects & Other Types of Failures)
10. Digital Microscopy11. Digital Photography
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Future Research Ideas (Some Thoughts)Future Research Ideas (Some Thoughts)1. Chloride Tolerance on Various Steel Substrate Conditions
• Test Methods – Accuracy and New Methods• Threshold Values – 7 µg/cm2 (?)
2. Field Coating Performance Monitoring Devices • Thermography• Sensors, etc.
3. Protective Barrier Systems for Concrete Bridge Structures• Waterproofing Membranes for Bridge Decks• Traditional Coating Systems
4. Signage and Pavement Markings
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER
EIS Test Cells for Field MonitoringEIS Test Cells for Field Monitoring