Small hair-like cracks in concrete can become problematic if they do what?

Small hair-like cracks in concrete can become problematic particularly when they extend to the rebar. This is crucial because rebar serves as reinforcement within the concrete, providing structural integrity and support. If the cracks reach the rebar, they can allow moisture and corrosive substances to penetrate, leading to corrosion of the rebar. Corrosion can weaken the structural support provided by the rebars, potentially resulting in more significant issues such as spalling, structural failure, or compromised safety over time.

While it is true that larger cracks, visible surface changes, and those occurring due to weather can also lead to issues, the direct threat posed by cracks reaching the rebar is a critical concern in the integrity of concrete structures. The health of the rebar is essential for maintaining the structural life and safety of concrete elements.