What is the primary purpose of control joints placed in concrete driveways?

Control joints are intentionally created grooves or cuts in concrete surfaces, including driveways, designed primarily to control where cracks occur. Concrete is prone to shrinkage as it dries and sets, and without these joints, cracks can form randomly throughout the concrete slab, leading to unsightly damage and compromise in structural integrity.

By placing control joints at strategically determined intervals, the concrete is given designated locations to crack, which helps to mitigate the random cracking that can occur from environmental factors like temperature changes and moisture levels. This strategic placement ensures that, instead of spreading unevenly across the entire surface, any cracking that does occur is contained and less noticeable, thus improving the overall longevity and serviceability of the driveway.

While control joints also indirectly contribute to other aspects, such as enhancing the appearance by creating a more uniform look and facilitating drainage by managing surface water flow, their primary function is to minimize and direct cracking, making this the most accurate choice.