Goals:

Performance Criteria:

• Require a 5-year warranty on crevice corrosion and pack rust plus a minimum 25+ year coating life.

Warranties:

• Two-year Bonded / Three-year Contractual.

Coatings Selection:

• The project required a surface tolerant coating system, compatible with water cleaning, to be applied over rusted steel and an existing red lead alkyd system. The coating used would also need to be 'active' in the pack rusted joints and connections.

 Surface Preparation:

The original intention was to abrasive blast to a SP10 for Zone 1, however this was cost prohibitive ('negative air' and containment were major cost items).

CN then looked at waterjetting and high pressure water cleaning, which meant a simpler containment process and no 'negative air'. This alternative reduced the cost on the first phase of the project by 50%, with no performance penalty.

Inspection Standards:

SSPC SP12/NACE 5, as the written standard.

SSPC VIS 4-I, as the visual standard.

COATING SYSTEM APPLICATION

The Termarust Series Coating System:

A stripe coat of TR2200 Penetrant/Sealer , was applied to all pack rusted joints, connections and rivets. TC2200 Penetrant/Sealer soaks into the joints, displaces moisture, neutralizes the acid which fuels the corrosion and ensures system activity.

Zone #1 (Splash Zone):

5-7 mils DFT of TR 2100 Primer/Topcoat was applied to all bare metal areas prepared to a SSPC-SP12-WJ3L-SC2.

Zone #2 (Balance of Bridge);

Spot prime @ 2-3 mils DFT of TR 2100 Primer/Topcoat was applied to all areas of tightly adhered rust.

All Zone #1 and #2:

Received a topcoat of 5-7 mils DFT of TR2100 Primer/Topcoat.

Zone #1:

The splash zone received an additional coat of TR 2301 @ 1.5 - 2 mils DFT.

TR 2301 Splash Zone Coating is designed to keep the splash zone areas free of dirt build-up.

NOTE: In the second year of Phase I, due to TR 2100 superior performance after a long winter, the owner stopped using TR 2301 as the TR 2200 alone met their cosmetics criteria.

TR2100 Primer/Topcoat (pH of 10) neutralizes acidity and has a high polar attraction to steel which allows it to wet the metal profile and displace moisture. TR 2100 crystalline platelet structure creates a superior hydrophobic barrier because the crystals align at the surface (similar to fish scales).

TR 2200 Penetrant/Sealer is applied:

To all pack rusted joints, seams, connections and where any gaps appear.

TR 2100 Primer/Topcoat is applied:

As a stripe coat on all pack rusted joints and connections, rivets, bolts, seams and edges.As a topcoat of 5.0 to 7.0 mils DFT on all surfaces.

(Note: all these processes are applied wet on wet)

TR 2300 Specialized Protective Coatings is applied:

A coat of 1.5 - 2.0 mils DFT Termarust 2301 Splash Zone coating was applied to all surfaces in Zone 1, as indicated in the specification.

WARRANTIES

The restoration of the Quebec Bridge is covered by a 5-year warranty jointly supplied by the contractor/applicator and coating manufacturer.

The warranty covers corrosion on all surfaces with no exclusion and includes pack rusted joints and crevice corrosion, however it does allow rusting to a SSPC- VIS 2-82, rust grade 9 (0.03% of the painted surface).

The Termarust Technologies’ warranty is secured by a two-year bonded and an additional three-year contractual warranty.

Inspection Requirements:

• Quality Control provided by the contractor, must meet the requirements of QP1/QP2 (similar to ISO 9000) (QP1 is for a quality control program, QP2 relates to lead removal)
• Contractor must provide daily QC reports to the consultant
• Consultant must perform QA checks for each aspect of work Consultant must ensure all workers have received lead training
• Consultant must ensure the contractor/applicator meets specification requirements

Quality Assurance Provided by the Consultant:

• Review all documentation submitted
• Verify contractor's equipment, calibration of equipment
• Confirm that the work committed to in the tender is completed as per the specification requirements.
• Advise the owner regarding any problems with respect to the specification, surface prep, submissions, health and safety, environmental issues, the product used, problems with the data sheets, etc.
• The consultant must check the contractor's QC to ensure the specification requirements are met.

Typical Inspection Defects Include:

• Moisture
• Misses
• Poor surface preparation
• Coating adhesion
• Not maintaining proper 'stand-off' distances
• Adhesion Tests are performed at each location. After surface prep, 'X-cut', mechanical and hydraulic testing is performed. Representative values are kept for CN to review.
• A Risk Assessment of the surface prep method, adhesion of the existing coating and overcoat system, was conducted by CN prior to the development of the coating specification.

Summary

1. CN and their consultants developed a performance based, structure specific specification using water for surface preparation.
2. A 50% cost saving was realized by using water. This allowed the Quebec Bridge Restoration project to stay within budget.
3. Performance goals were established and secured with a contractor/applicator and coating manufacturers warranty.
4. A detailed inspection (Quality Control and Quality Assurance) program was developed to administrate the specification.