Final answer:
An isolation joint, also known as an expansion joint, is used to separate a structural column from a concrete slab to allow for independent movement and prevent damage.
Step-by-step explanation:
The type of joint used to separate a structural column from a slab in concrete construction is commonly referred to as an isolation joint or expansion joint. This joint is designed to allow for independent movement between the structural elements to avoid potential damage from thermal expansion, shrinkage, or other forces. The isolation joint is typically created by inserting a preformed compressible material that can absorb the movement between the column and the slab, ensuring that loads are not transferred and that each element can behave independently.