If anything it would be difficult to screw the cbu into the concrete especially with the middle layer of thin set.
How to install tile on a concrete basement floor.
Mop the entire floor area of your basement as any dirt or dust is a potential hazard to the success of your tiling job.
Mortar is basically the adhesive that helps the tile stick to the concrete so choose the one that best suits your needs and your current situation.
Most tile professionals agree that attaching a cbu to a concrete floor would be more trouble than it is worth.
The next step is to apply a concrete sealer on the floor surface.
The commercially available mortars generally need to be mixed with a proportional amount of water.
It will also provide a stronger adhesion between mortar and concrete.
Pour just about an entire bag of the dry mixture into a large bucket.
Once everything is ready start by applying a layer of mortar to the floor.
A concrete sealer prevents moisture from staying underneath the ceramic tiles.
This is an optional step but can really benefit your tile installation in the long run.
Step 3 plan your layout.
Step 2 cleaning the concrete flooring.
Continue to mix until the texture is creamy.
Add just enough water to get the dry mixture wet and begin mixing.
Use a self mix thin set mortar for the tile installation.
After mopping allow your concrete.
In short installing cement board between concrete and tile is possible.