North Carolina Building Contractor License Practice Exam

Which type of joints allow for both vertical and horizontal movement in concrete?

1. Control joints

2. Expansion joints

3. Construction joints

4. Isolation joints

The correct answer is: Expansion joints

Expansion joints are specifically designed to accommodate the movement that occurs in concrete structures due to factors like temperature changes, curing, and moisture variations. These joints allow for both vertical and horizontal movement, providing the necessary flexibility to prevent cracking or damage to the concrete when it expands or contracts. In a concrete structure, as temperatures rise, the concrete tends to expand; conversely, it shrinks when temperatures drop. By incorporating expansion joints, builders ensure that there's a designated space for this movement, maintaining the integrity of the overall structure. Control joints are primarily used to manage cracking by directing it to predetermined locations but do not allow for vertical movement. Construction joints serve as a stopping point in the pouring of concrete and do not typically accommodate movement. Isolation joints separate the concrete from other structures, allowing for independent movement but are more focused on vertical separation than on horizontal movement.