What kind of deterioration can make a concrete tie defective according to FRA?

A concrete tie may be deemed defective if the deterioration leads to visible prestressing material. This condition is alarming because it indicates a significant compromise in the integrity and structural performance of the tie. Prestressing is a process used to enhance the strength of concrete, and if the prestressing strands are visible, it typically suggests that the concrete has degraded to the point where it no longer provides adequate support and protection for these critical components. This situation could lead to reduced load-carrying capacity and increased risk of failure, necessitating immediate attention and potential replacement.

Other forms of deterioration, such as crumbling or minor surface scratches, although concerning, do not necessarily indicate an immediate loss of structural integrity essential for safety. Insufficient fastener loads, too, indicate issues with connectivity to the rail but may not directly pertain to the physical condition of the concrete tie itself. Thus, visible prestressing material serves as a clear warning sign of more severe underlying issues.