What is the primary function of concrete expansion joints?

The primary function of concrete expansion joints is to allow for movement caused by temperature changes. Concrete is a material that expands when heated and contracts when cooled. These thermal movements can lead to cracking if there is no provision for movement within the structure. Expansion joints are essential because they accommodate this movement, helping to prevent damage from temperature fluctuations.

When designed properly, these joints can absorb the stresses associated with expansion and contraction, ensuring the overall longevity and stability of the concrete structure. This feature is particularly important in larger slabs, bridges, and pavements, where significant temperature changes are common. The inclusion of expansion joints allows for a controlled means of movement, thus enhancing the performance and durability of the concrete.