In a bonded, post-tensioned slab, what is required to prevent corrosion?

• A. Plastic covering
• B. Concrete encasement
• C. Steel sheath
• D. Metal covering

Answer: (A)

In a bonded, post-tensioned slab, preventing corrosion is crucial to ensure the longevity and structural integrity of the system. A plastic covering is essential as it acts as a protective barrier around the tendon, insulating it from moisture and other corrosive elements that could lead to deterioration over time. This method effectively seals out water and aggressive chemicals from the surrounding environment, thereby preserving the steel tendons within the concrete.

While concrete encasement, a steel sheath, or metal covering may serve some protective functions, they do not specifically provide the same level of moisture protection needed in this context. Concrete can still be permeable and may allow moisture to reach the steel, while metal coverings can create a risk of corrosion themselves if not properly managed. Thus, the use of plastic covering is the most effective measure to prevent corrosion in a post-tensioned slab system.