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Ecodur 201: Rail Bridge Coating

Rail Bridge Coating

With America’s infrastructure that includes, bridges, pipelines, highways etc. getting a constant ‘D’ rating and in need of urgent rehabilitation that could run into the trillions of dollars if ever such a program is fully implemented, simple solutions such as extremely long lasting coatings are a highly cost-effective answer to extending the life of steel structures.
An example are railway bridges like this one in the Colorado Rockies. A relatively small structure, this one nevertheless bridges a water course that is subject to flash flooding. It provides a vital link to a busy quarry and in the summer months, especially, it additionally sees frequent tourist train traffic.

Problem
The line’s traffic schedule presented the problem of how to get the bridge work done without interrupting the passenger and freight services. The bridge did not just have to be prepped to NACE 2 and sometimes NACE 3 levels which is time consuming, it needed a durable coat with a quick curing cycle that would not present a period of emissions of Volatile Organic Compounds which can be harmful to health and force passenger train delays.

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The altitude of the bridge meant that a coating had to able to withstand temperature extremes that cause steel to expand and contract. Many conventional epoxies simply cannot tolerate such conditions, rapidly causing micro-cracking that allows in moisture and quickly leads to corrosion.

Whilst the temperatures at the time of application were mostly well above freezing during the day, they plummeted to below freezing at night. This temperature variable can delay and sometimes fully hinder a complete cure with conventional epoxies.

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Solution
Ecodur has an outstanding cold weather performance, well below those that were experienced at the time of application in early March, 2017. Being essentially a plasticized gypsum that is completely non-toxic, it has double the adhesion of most epoxies and permanently retains a high degree of tolerance for expansion and contraction of the substrate – in this case steel.
Furthermore, should any repairs be required now, or in the indefinite future, provided the original coating is clean and dry, repair patches will fully bond to the original Ecodur.

More than 20 years of testing on roads and public garages have demonstrated Ecodur’s high impact resistance so falling stray bits of gravel will have little effect whereas the brittle nature of many conventional epoxies makes them highly susceptible to impact damage.

Similarly, chemicals commonly encountered on railroad lines such as salts and creosotes are fully resisted by Ecodur which has been well proven in the oil patch where over a thousand oil and production water tanks with their chemical cocktails have been coated.

Application Results
Proper preparation was the key. Clean, bare steel free of rust flakes was done to a 3-mil profile. The Ecodur was manually applied. Because of the necessity to speed up the cure time, a slightly higher volume of catalyst was used which speeded up the initial cure from 30 minutes down to 20 minutes.

Full hardness was achieved in less than 24 hours at which point, following a final inspection, the bridge coating project performed by Elite Protective Coatings, was declared completed. The client subsequently express complete satisfaction with the coating and the process. As a direct result of the one coat and quick cure solution, no passenger or freight traffic was interrupted or cancelled.