Water Resistant Mortar

We have a new concrete water tank for cement plant and the drawing specifies that the concrete wall on the inside is to be coated with 20mm water resistant mortar on the concrete walls. What would be the proportions of cement\lime and sand for such mortar, what type of sand (i.e. course or fine) what type of lime ( hydraulic lime, non-hydraulic lime)?
There is no more specifications regarding the mortar (only on a drawing) and there is no way to obtain any information from the designer (it is another story why that is), so I am on my own. The only thing is that the tank’s walls are constructed from concrete category S2…so it is my task to specify the mortar mix…


I think you should be looking at waterproofing treatments, not mortar, for a new concrete tank. Google crystalline concrete waterproofing and you will find a few manufacturers.

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