In the following bridge preservation project, the HRCSA maintenance coating was applied to a minimally prepared steel substrate (WJ4 || WA1 ) inside a highly condensed period of time (2 weeks of rail line shut-down).
The steel bridge as it WAS before WJ4 || SA1 surface preparation and HRCSA application.
One Year After the Bridge Overcoating Initiative.
Coating Systems: Beautification or Corrosion Mitigation Initiative?
The US Federal Highway Administration strongly promotes maintaining existing infrastructure in a “Good State of Repair”. This has lead to a great emphasis on “doing more with less” by focusing on bridge preservation practices designed around extending the service life of the existing structures. Mitigating corrosion is a big part of this formula.
The British structure featured in today’s discussion reveals how structures can be preserved cost effectively and with minimal preparation – regardless of tight time schedule pressures.
What the sections which were applied to specification look after 7 years. (No undercuttin).
- Most areas were prepared and corrosion mitigated to specification.
- Some areas were missed during the works (Time constraints, access limitations).
- ALL ACTIVE CORROSION HOTSPOTS CAN BE VERY QUICKLY AND EASILY REPAIRED WITH POWER AND HAND TOOL CLEANING.
The two circled areas of concern in this photograph are active corrosion hotspots which showed up after the application of chemically active HRCSA materials that triggered the delaminating of tightly adhered black oxide patches. HRCSA chemistries cause heavily contaminated black oxide spots to detach. (See repair procedure bottom of page).
The browned areas reveal bridge immersion from brackish Ouse River water during two separate floodings.
In the circled area, rust bleeding is coming from where previously salt contaminated delaminating coating was missed during surface preparation before the application of the HRCSA self-priming topcoat. A complete repair of this active corrosion hotspot can be achieved in very short order using a right angle sander, solvent wipe and brushed on application of single component, single coat HRCSA self-priming topcoat.
This photo demonstrates the excellent surface wetting and polar bonding of the HRCSA system on heavily pitted and previously heavily corroding substrate (Pressure washed then coated). Salts had been very effectively mitigated during surface preparation else it would have shown through the applied coating material. The coating profile shows no signs of deterioration and is working properly to protect the substrate from the elements.
Another fine example of excellent surface wetting and polar bonding of the HRCSA system to heavily pitted and corroded steel substrate. The coating shows no signs of deterioration and is working properly. Pitted areas (black oxide delaminations) can be quickly and easily repaired using the attached repair procedure below.
Further evidence of discoloration caused by the brackish flood waters as they rose up the side of the girder. Although the coating may be have been discolored there is no corrosion or damage triggered by the brackish floodwaters.
There can be many reasons why hard to reach areas get overlooked during busy works and stressful time constraints. These can include machine failures, weather constraints and so forth. Fortunately, HRCSA repairs can be quick and easy using the repair procedure defined below. [Note: Less than 1% of the surface area was affected.]
In the following examples, inadequate surface preparation and salt removal causing premature coating failures on the sections highlighted below.
