I've heard the term pinwheel joint used in connection with concrete floors. What is a pinwheel joint?
The drawing below shows a plan view of this type of joint, named for its resemblance to a pinwheel. Since this joint type eliminates one step in construction, pinwheel joints sometimes replace the diamond or circular column-isolation joints typically used in industrial floors. It reportedly also produces a cleaner detail at the column. The fibrous isolation-joint material is clamped to the column before floor construction. As the concrete floor is poured, workers also place concrete within the column H-section to support the isolation-joint material. Durable Concrete for Ice Skating Rink