Which bridge deck material is known for its resistance to decaying agents?

The bridge deck material notable for its resistance to decaying agents is timber, particularly when it is treated properly. While timber is generally perceived as vulnerable to rot and decay due to moisture, the use of preservatives and modern treatment methods can significantly enhance its durability against various environmental factors. These treatments help protect against mold, fungi, and insect damage, which are common decaying agents.

In contrast, while steel is durable and strong, it is prone to corrosion if not properly maintained and protected, particularly in moist or salty environments. Concrete, though very robust and commonly used for bridge decks, can suffer from issues like cracking and spalling, especially when exposed to aggressive chemical environments. Rubber is not typically used as a primary deck material; rather, it serves specific functions such as expansion joints or protective layers but does not embody the qualities of resistance to decay in the same manner as treated timber does. Thus, timber can be considered the best choice in this context when adequately treated to combat decay.