Cement as a Tank Lining Material

[corrosionman]

Portland cement is used extensively as a Pipe lining coating. Such coatings are only approx 8 mm thick and I hear that it is their shape that holds them in place.
Would a hand applied (trowelled) coating be any use for large tank linings. We have many large Carbon Steel tanks which need re-lining. They have an epoxy resin lining which is failing and contain potash salt slurry which is corrosive. They are difficult to get completely dry and maybe a cement lining would tolerate the damp walls and still have enough natural bond to remain in position. We even wondered about adding Zinc dust to create a water based zinc rich primer
Any comments will be much appreciated. ( I expect them all to be negative so please shout up.)

 

[Metalguy]

I've worked with some large (120" dia) cement-lined steel pipe where short steel studs were welded to the ID, and a steel mesh was then welded to the studs. Cement was then sprayed on.

"I'm that dog who saw a rainbow, only none of the other dogs believed me." from "Kate and Leopold"

 

[kenvlach]

I don't much like the idea of using Portland cement-type concrete to patch epoxy resin. Had a bad experience with fresh concrete reacting with epoxy. The high alkalinity reacted with the epoxy and left a powdery interface.
Also, zinc powder in fresh concrete mix will react to form hydroxide and bubbles, I suspect a reaction like this:

Zn + 2H₂O, @pH 13 --> Zn(OH)₂ + H₂(g)

Do the tanks need complete re-lining or just patching? You will need to find a resin compatible with the existing one & traces of moisture, and resistant to the potash slurry. What was used originally?

 

[0707]

a suitable hpoxy resin reinforced with glass cloth fiber could be an option for your tank. Specialists on this type of lining will help you on the choice of the proper resin for your service.

regards

Luis

 

[corrosionman]

Many thanks for all your interest.There are several difficulties with this tank which generated my thoughts on a water based cement. First, the tank is in a very damp humid condition - - the salt seems to be "engrained"into the steel wall and no matter how much it is washed or blasted it feels damp and goes rusty within a couple of hours so a resin / epoxy lining does not bond very well.
Secondly all resins have a expansion rate about 7 times that of steel so in operational state there is a shrinkage or expansion force trying to disbond the lining.
This tank had extensive re-lining last year and it has failed , thats why I am looking at it now, hence my query.
Also a water based product is much easier to apply than a resin. However we are now setting up a few practical tests to see if cement bonds to blasted steel that is damp and salty so I'll update you on the results next week.
Thanks for input CM

 

[Metalguy]

You need to remember that Portland cement/sand mixes have poor tensile and bending strength, but have fairly good compressive strength. Water shouldn't hurt the bond-may even help as concrete cured underwater is great.

If you can get rid of all the resin and weld the steel supports to the ID, you should be OK.

"I'm that dog who saw a rainbow, only none of the other dogs believed me." from "Kate and Leopold"

 

[rustbuster]

You should contact TAC Inc. They do alot of corrosion / abrasion resistant linings for chemical tanks, pulp & paper etc. Go to info@tac.ca for information.

Good luck

 

[triflowcorrosion]

Where are you applying this (State)? What is the tank holding? What is the exact material already used? What is the size of the tank? Depending on the material the tank is holding, we can reline the tank with a 10 year guarantee. Could very well reline over existing material, or have to remove it. I would strongly suggest that using cement in a damp/moist environment is not a great idea. rfernley@triflow.ca Let me know the info above and I may be of assistance