Joint, Expansion

Definition

An expansion joint is a joint through tile, mortar, concrete, or masonry down to the substrate, intended to allow for gross movement due to thermal stress or material shrinkage. It is a discontinuity or break designed to permit movement.

Purpose

The primary purpose of an expansion joint is to absorb and accommodate the expansion and contraction of building materials due to temperature changes, preventing damage such as cracking or buckling.

Examples of Use

1. Bridges and Highways: Expansion joints are essential in bridges and highways to accommodate thermal expansion and contraction.
2. Building Facades: In large building facades, expansion joints prevent cracks caused by temperature-induced expansion and contraction of materials.
3. Concrete Floors: Expansion joints in large concrete floors prevent buckling and cracking due to temperature changes and material shrinkage.

Related Terms

• Contraction Joint: A joint that controls cracking by creating predetermined weak points.
• Control Joint: Similar to contraction joints, used to manage where cracks occur.
• Thermal Expansion: The increase in material dimensions due to temperature rise.

Notes

Expansion joints must be properly designed and placed to function effectively. They should be filled with flexible material that can accommodate the expected movements while maintaining a seal.