What is required when concrete placement is interrupted or work has concluded for the day?

When concrete placement is interrupted or when work concludes for the day, a construction joint is necessary to ensure a proper bond and alignment between the different sections of concrete that are poured at different times. Construction joints are specifically designed to accommodate these interruptions, allowing future concrete placements to connect seamlessly with the previously poured concrete.

These joints are important for maintaining structural integrity, as they provide a defined location for the new concrete to bond with the old concrete. Without a properly formed construction joint, issues such as cracking, uneven surfaces, and poor structural performance can arise due to the lack of support and bonding.

In contrast, other types of joints serve different purposes: expansion joints accommodate movement due to temperature changes, isolation joints separate different materials, and contraction joints are designed to manage cracking due to shrinkage. Thus, for situations involving work stoppage or interruptions in pouring, the use of a construction joint is crucial for ensuring the durability and stability of the concrete structure.