CALGARY, Alta. - The use of road salt has become an institutional solution to creating safe and drivable roadways during the snow-filled winter months - but it comes at a cost to equipment operators....
WINTER WEAR: Nobody knows more about salt corrosion than those who operate dump trucks for municipalities.
CALGARY, Alta. – The use of road salt has become an institutional solution to creating safe and drivable roadways during the snow-filled winter months – but it comes at a cost to equipment operators.
On average about five million tonnes of road salt is spread each year on roadways across the country, eating away at truck frames and undercarriages.
Discovered as an effective solution to snow and ice control in the ’30s, the use of road salts in conjunction with plowing became widespread throughout Canada in the ’60s.
With a significant increase to the rusting of vehicles in the ’70s, the effect sodium chloride has on its surrounding environment has been widely debated.
Environment Canada undertook a five-year study to assess the issues resulting from chlorides in the environment.
The study focused on road salts containing sodium chloride, calcium chloride, magnesium chloride and potassium chloride.
Chloride works as a catalyst in the oxidization process and the report, published in 2001, supported the continued use of road salt.
However, it recommended a number of ways to better manage distribution practices, lowering the amount of road salts used and hopefully reducing corrosion.
Many applications of road salt today are applied using a “pre-wetting” system.
Road salt begins working to melt ice and snow once it becomes wet, therefore applying a light brine spray before salt distribution allows the road salt to begin working immediately and stick to the surface once laid down, leaving lower traces of chloride in the air.
Combinations of salt and sand are also common practice.
Generally salt only works to about -10 C and the sand provides traction for wheels in contact with snow.
As new alternatives continue to be researched, chlorides continue to be the main combatant against dangerous winter driving conditions and a concern for rust on vehicles.
With close to one million kilometres of roads in Canada, a number of dump trucks are utilized in the transfer and distribution of road salts in needed areas.
Although non-corroding materials and improved paint coatings have aided in slowing the corrosion process, the trucks in the front line of the rock salt distribution must take special precautions to battle corrosion.
Know the product
To aid in corrosion prevention it is important to know what makes up the truck box being used.
“I’d caution against bi-metals, any combination of aluminum or steel together, in any application,” said John Ivany, fleet manager with the City of Moncton, N.B. “When you have two types of metals the weaker metal works as an anode. I’d be very, very careful with aluminum.”
It’s the motto of the Boy Scouts and when it comes to preventing corrosion in trucks it also makes sense. A number of application products offer protection against rust and slow down the corrosion process.
“Prep the metal properly with a good primer and paint,” said Ivany.
In Nanaimo, B.C. the city uses plows and sanders to keep roadways safe for travel and the island city uses two different application products to help dispel rust.
“For us the most problematic areas are in the cabs of the truck on the floors,” explained Mike Hacking, fleet manager for the Pacific coast city. “In our case what we generally do is paint the floors.”
The two differing applications work in different ways.
One product is used in conjunction with paint to prevent rust from starting; while the other product is a rust converter used to neutralize oxidization and prevent further corrosion.
A number of light-duty trucks can be equipped with box-liners to prevent rust and corrosion in pick-up boxes. Hacking says the same liner can be adapted to problematic areas of dump trucks and his fleet uses two different brands.
“We’ve done the floor of a couple of our trucks with it and it’s basically a rubber coating,” he explained.
Wiring in trucks can be especially susceptible to salt corrosion. Corrosion is an electrochemical process and the established electric current can speed up the process. It is recommended to never reduce the integrity of wiring by tampering with the coating.
“We use a dielectric grease at the connectors and the connectors are sealed with a shrink wrap tube,” explained Hacking. “We also use a marine grade wire, which is generally used out on vessels in the water, when we do any wiring.”
Keep it clean
With all the products on the market to reduce corrosion and slow down the corrosion process, the best defense is to reduce the amount of time salt is in contact with the metal.
“We wash the equipment quite regularly and undercoat the equipment a couple of times a year,” noted Ivany.
“But you want to keep salt away from bare metal. Keep it clean and get the salt washed off as often as you can.”
Until a completely rustproof truck is created, salt will be the kryptonite to many super trucks. In the meantime, the replacement of corroded trucks is a reality to many fleet owners and managers, and can be an expensive task.
Taking the time to invest in preventive measures can make a large difference in the end.
“You just have to use a quality product,” said Hacking. “It may cost a little more, but in the long-run it will cost a lot less.”