Abstract
Visual inspection and field experience from concrete railroad sleepers (crossties) provide evidence that cyclic loading of train axles accelerates their degradation in areas of high precipitation. Because prestressing forces close flexural cracks after every load application, this repetitive motion generates water flow within cracks. In this study, multiple mechanisms are systematically investigated through laboratory experimentation to understand the deterioration of concrete in cracked prestressed beams exposed to moisture and under cyclic loading. Results identified abrasion as the leading degradation mechanism. High hydraulic pressures, cavitation, and leaching damage are also investigated but seem less likely to govern this problem.