ACI Concrete Flatwork Finishing Certification 2025 – 400 Free Practice Questions to Pass the Exam

Control joints play a crucial role in managing the natural cracking that occurs in concrete slabs. When concrete cures, it undergoes expansion and contraction due to temperature changes and moisture loss. Without control joints, these inevitable movements can create random cracks that compromise the integrity and appearance of the slab.

By incorporating control joints, which are intentional lines cut into the surface of the concrete, the material is allowed to expand and contract in a controlled manner. This helps to direct where cracks will occur, allowing them to happen along the joints rather than creating unsightly and unpredictable cracks throughout the slab. Thus, the correct answer emphasizes the function of control joints in accommodating the thermal and moisture-related dimensional changes of concrete, ensuring the overall durability and aesthetics of the finished product.