Concrete countertop mixes use additives to increase strength and reduce cracks.
Other additives are used to make the concrete flow better. This makes it easier to jig the concrete and release air bubbles.
To build the best countertops, you need the right concrete mix. You have two main options, buy pre-mixed concrete or make your batch.
A good mix for concrete countertops should.
Have a law water-cement ratio to prevent shrinkage cracks.
Provide high compressive strength.
Be easy to work with.
Have good surface quality.
If this is your first time making concrete countertops, I recommend buying premixed ones. Just use the correct amount of water and pour it into the forms.
Cement is permanent. Cement is a popular choice as a countertop surface right now, but in ten years, it might feel dated and old, and removing them will be difficult.