Structural Failure of Pretensioned Concrete Sleepers under Cyclic Loading Due to Water Flow in Cracks

Pretensioned concrete sleepers are vulnerable to structural failure when flexural cracks develop in moisture-rich environments. This study presents experimental evidence showing that water ingress in cracked regions leads to accelerated degradation under cyclic loading. Tests conducted on full-scale sleepers and small-scale prisms revealed that (1) debonding between tendons and concrete significantly increases compressive stresses, and (2) moisture reduces the concrete’s compressive strength. Notably, post-tensioned sleepers exhibited greater resistance to failure under similar conditions. Tendon corrosion, while a long-term concern, was not a contributing factor within the observed failure timeframe. These findings support recommendations for improved drainage and favoring unbonded post-tensioned systems in high-moisture settings.