pile corrosion protection

[cvg]

plan is to chip off the caliche coating, [sand blast] and coat with [zinc primer] or [coal tar] or [epoxy coating] and then construct a concrete apron.

Not sure what the best approach is, any thoughts?

 

[damorim]

Depends how much the Client is willing to spend? Sandblasting and metallizing would likely the best best... Waterblasting and painting (epoxy) if you are worried about budget. Any consideration to lining the channel with a rip-rap blanket rather than a concrete apron? Would be quicker/cheaper as well.

 

[dik]

Caution: Many tar modified epoxies are carcinogenic.

Dik

 

[MotorCity]

If it were me and money was of no concern, I'd sand blast and epoxy coat. Might cost more upfront, but it would pay dividends later in low maintenance.

 

[cvg]

so what if I just blast and coat the bottom where it is below the proposed lininng and let them work on the rest of the piles in the future if they want. Frankly, I dont think anything has been done to maintain these for 60 years

 

[wiktor]

The best approach will be to sand blast and prime with zinc rich primer. You may also add two or three galvanic anodes per pile embedded in the concrete apron and connected to the pile.
Galvanic anodes are here:

https://www.vector-corrosion.com/galvanic-anodes

 

[dik]

zinc 'hockey pucks' would be good...

dik

 

[damorim]

I'll send down some Winnipeg Jets pucks! haha

 

[oldestguy]

With a concrete slab, how do you know some future gully washer will not undermine it and then what do they have? Rip-rap sounds more suitable.

 

[cvg]

we are handling the scour part of the project with a combination of things but riprap under the bridge is not a preferred option in this case

 

[BridgeSmith]

Yeah, them cows don't like walking on riprap very much. More to the point, the ranchers get mighty ticked if you put riprap where they want the cows to go. For those situations, we've occasionally used a "smooth grouted riprap" system, which essentially involves putting down the riprap and then pouring high slump concrete enough to cover the rocks.

 

[damorim]

Haha, first time I've heard about having to take cows into consideration in the design... clearly not a design constraint in my neck of the woods! I imagine they wouldn't be too pleased with rip-rap in that case.

 

[BridgeSmith]

I just assumed that was the reason when I saw what looked to be hoof prints from cattle in the photo.

 

[cvg]

I think horses are more of a concern than cows on this particular project

 

[BridgeSmith]

Yeah, horses trying to walk on riprap would definitely be a problem. For that matter, riprap is a problem for anything with hooves to walk on.