Final answer:
Water reaches steel in reinforced concrete primarily through cracks and porosity, which can lead to corrosion, a significant problem for infrastructure integrity.
Step-by-step explanation:
Water can reach steel in reinforced concrete in a couple of ways. One way is through cracks that may form in the concrete due to various reasons such as thermal expansion and contraction, drying shrinkage, or structural overload. As water seeps through these cracks, it comes into direct contact with the steel reinforcement. Another way water can reach the steel is through the concrete's porosity. Concrete is naturally porous to some degree, and if it's not properly cured or has a high water-to-cement ratio, it can allow moisture to penetrate through its matrix and reach the steel. This exposure to water can lead to corrosion, which is a significant problem that requires considerable resources to address, as evidenced by infrastructure issues like the collapse of the Silver Bridge.