I watched a video on the construction of Burj Khalifa, Dubai. The construction engineers answered that they're using a special type of protection known as Cathodic protection to protect from the corrosion due to local ground water. They told a compound named "Polymer Slurry" (What's that?). They're using viscous Polymer Slurry as their basic coat to dump the high density & low permeability concrete in order to create a "GOOD FOUNDATION". What is it made of? (Simply any polymer?) And what does it do? Does it actually repel water? Many organic compounds repel water... Then Why this?
After reading the link provided in the question, and doing a little googling, of "polymer slurry" and "foundation", I found something useful.
Polymer slurry seems to be made of one or more hydrophilic superabsorbent polymers, such as polyethylene glycol, polyvinyl alcohol, or carboxymethylcellulose that produce a thick viscous slurry when mixed with water. It does not repel water so much as the opposite. It is so hydrophilic that it absorbs water before the water can reach the concrete or the steel. Then this slurry becomes thicker the more water it absorbs so that the rate of diffusion of water through the slurry decreases. Ultimately, this action creates a hydrogel, which may be quite strong, despite being mostly water, due to extensive hydrogen bond crosslinks.
Other applications of polymer slurry seem to be in the drilling industry to modulate the viscosity of drilling fluids.
The polymer slurry has the purpose of keeping the hole stable, while it is still being worked on.
While building a 50 m deep hole, I think it's common to need to change or replace the tool, when it broke, or the type of ground changed.
Changing the thing on the other end of 50 m steel rod means to pull out the rod, make the change, and let it down again.
But even without any change, the rod needs to be pulled out before filling with concrete, I think.
The slurry does not repell water on the surface like oil would, but it repels ground water from entering the bore hole by having a higher pressure.
The pressure comes from a higher density and same depth below ground.
One useful effect of the polymer could be that it does not soak into dry parts of the hole wall.
Over 50 m of hole wall, a touching rod will ceartainly loosen some sand, but id will not just drop to the end - depending on the slurry and the particle size, it will sink slowly, or even not at all.
So, large boreholes were dug 164 feet (50 m) deep and then filled with viscous polymer slurry to maintain the stability of the hole. The slurry is denser than water, but lighter than concrete. The concrete, when poured into the hole, displaces the slurry and hardens to form a foundation pile.