Which term describes joints that separate slabs from walls and columns?

Which term describes joints that separate slabs from walls and columns?

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

Answer: (A)

Isolation joints separate a concrete slab from surrounding walls and columns to allow the slab and the structural frame to move independently. This movement comes from shrinkage, settlement, and temperature changes, and keeping the slab isolated prevents cracks in the slab from transferring into the walls or columns. The joint is typically filled with a flexible material so the slab can slide slightly without restraining the frame. Other joint types have different roles: expansion joints accommodate length changes due to temperature in structures, control joints create predictable cracking lines within the slab, and construction joints are where pours are stopped and later continued. Therefore, the term that describes joints separating slabs from walls and columns is isolation joints.

Isolation joints separate a concrete slab from surrounding walls and columns to allow the slab and the structural frame to move independently. This movement comes from shrinkage, settlement, and temperature changes, and keeping the slab isolated prevents cracks in the slab from transferring into the walls or columns. The joint is typically filled with a flexible material so the slab can slide slightly without restraining the frame.

Other joint types have different roles: expansion joints accommodate length changes due to temperature in structures, control joints create predictable cracking lines within the slab, and construction joints are where pours are stopped and later continued. Therefore, the term that describes joints separating slabs from walls and columns is isolation joints.