Joints that separate slabs from walls and columns are called ________ joints.

Joints that separate slabs from walls and columns are called ________ joints.

• A. Isolation
• B. Construction
• C. Expansion
• D. Control

Answer: (A)

Isolation joints separate the horizontal slab from vertical elements like walls and columns to allow independent movement between them. This keeps cracking from moving through the structural parts when the slab shrinks, expands, or settles, by providing a gap that is filled with a compressible material so the two parts can slide relative to each other. This concept is distinct from expansion joints, which accommodate thermal expansion between structural segments; control joints, which are planned cracking lines within the slab; and construction joints, which tie fresh concrete to already hardened concrete.

Isolation joints separate the horizontal slab from vertical elements like walls and columns to allow independent movement between them. This keeps cracking from moving through the structural parts when the slab shrinks, expands, or settles, by providing a gap that is filled with a compressible material so the two parts can slide relative to each other. This concept is distinct from expansion joints, which accommodate thermal expansion between structural segments; control joints, which are planned cracking lines within the slab; and construction joints, which tie fresh concrete to already hardened concrete.