Abstract
Ballast fouling reduces the hydraulic conductivity and strength of ballast and can be detrimental to track performance. Therefore, it must be remediated when detected. While saturated and highly fouled conditions are readily detected using nondestructive methods such as ground penetrating radar, low to moderate fouling and unsaturated moisture conditions still pose a challenge. The objective of this research is to study low to moderately fouled ballast as a function of the interrelated properties and the strength and deformation response. The water holding capacity and shear strength were tested on one ballast aggregate and two different gradations of sand fouling materials which were collected from in service track. This paper describes the experimental methodology for ensuring replicate, large samples were tested at the same relative density, volumetric water content, and degree of fouling between two laboratories. The results showed that the strength of the ballast decreases continuously with the increase of the fouling percentage and water content intensifies the strength loss. Furthermore, it was found that the gradation of the fouling material is a critical factor influencing the mechanical response of the ballast. This study can shed light on the relationships between fouling, moisture, and ballast strength and deformation in varying conditions.