What is the purpose of an expansion joint in a sidewalk or walkway?

The purpose of an expansion joint in a sidewalk or walkway is to relieve stress and allow for movement. As concrete expands and contracts due to changes in temperature and moisture content, these joints provide a space that accommodates this movement. Without such joints, the concrete could crack or buckle under the stress of expansion, leading to a less durable and uneven surface.

The presence of expansion joints ensures that any movement is absorbed, thus maintaining the integrity of the sidewalk or walkway. This helps in prolonging the lifespan of the concrete structures and minimizing maintenance issues over time.