Use of a Multi-level Assessment Approach for Assessing Prestressed Concrete Sleepers Distressed by Internal Swelling Reactions (ISR)

Alkali-silica reaction (ASR) and internal sulfate attack (ISA) have compromised concrete sleepers both individually and combined. Although numerous studies have identified the cause, they have not effectively estimated the extent of the damage. This research assesses concrete sleepers of diverse ages using a multi-level assessment integrating microscopic and mechanical tools. The assessment encompassed visual inspection specifically focusing on crack openings normalized by a reference gauge, microscopic evaluations through the damage rating index (DRI), and mechanical tests, including the stiffness damage test (SDT) and compressive strength. The DRI revealed damage features associated with both aggregate particles and cement paste deriving from internal swelling reactions (ISR). Notably, the proportion of these features varied with the sleeper's age. Therefore, the multi-level approach proved effective in assessing the current condition of ISR-affected sleepers. Integrating this approach into regular inspections could potentially extend the lifespan of ISR-distressed sleepers.