The moisture seeps into the hole and then spreads to the rest of the rebar that is underneath the coating
Depending on where you live and the kind of environment it poses, you’ll be forced to approach long term building projects in different ways. For instance, roads in the north are constantly susceptible to freezing, thawing, and refreezing every single year. Cracks form in both concrete and asphalt and will line the highways in these areas. When I lived up north, I distinctly remember the feeling of hitting all of those bumps in the road while careening down the interstate at 70 to 80 miles per hour. The best thing the federal highway commission could do was fill the cracks with more asphalt, creating the distinctive ridge-shaped bumps that line the highways up north. But in the south near the coast lines, there are other stresses from the environment that pose serious risk for concrete and reinforced concrete alike. If you’re going to build something with reinforced concrete near the coasts, you better use corrosion resistant rebar tie wire or you could have a catastrophe after so many years of weathering and moisture exposure. That’s why some building contractors will utilize epoxy or PVC coated rebar, but those products are dangerous if the outer coating gets punctured during installation. The moisture seeps into the hole and then spreads to the rest of the rebar that is underneath the coating. This can lead to catastrophic corrosion and is extremely hard to fix. Otherwise you can use galvanized or stainless steel rebar tie wire for your reinforced concrete projects in coastal areas, but you will feel the extra cost burn a hole through your wallet.