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Mid-America Transportation Center

Properties of Fouled Recycled Ballast

Final Report
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University of Kansas


  • Principal Investigator: Robert Parsons ( (785)864-2946)
  • Co-Principal Investigator: Jie Han ( (785)864-3714)
  • Co-Principal Investigator: Thomas Glavinich ( 785-864-3435)
  • Project Status
  • Start Date: 06/01/2012
  • End Date: 12/31/2013
  • About this Project
    Brief Project Description & Background
    Railroad ballast becomes fouled over time as crushed ballast particles, coal dust, or clay from the beneath the ballast fills the ballast void space. Fouling reduces ballast strength and prevents drainage. When fouling becomes severe, maintenance actions are required. For this project we are investigating the performance of used/recycled ballast as it becomes fouled. Samples of cleaned, used ballast will be tested for strength, permeability, and electrical conductivity. Fouling material consisting of clay, crushed ballast fines, and coal will be added back to the ballast and the decline in performance will be monitored.
    Research Objective
    The objective of this project is to develop charts relating percentage of fouling to performance for each type of fouling material and to determine if electrical conductivity has potential as a method to evaluate the amount of fouling. The ultimate goal is to be able to determine when maintenance actions are needed before conditions degrade too much.
    Potential Benefits
    The potential benefits of the research include charts that can be used to describe the amount of fouling and its effect on performance, and proof of the concept that electrical conductivity may be effective at identification of fouled ballast in a non-destructive manner.
    A thorough understanding of railroad ballast drainage and strength properties is required for developing ballast specifications. While the properties of new ballast meeting AREMA specifications have been investigated, as much as 70 percent of the ballast applied to track during maintenance activities is recycled ballast. This ballast and a great deal of ballast currently in service under track has experienced degradation due to particle breakdown and rounding. The properties of recycled or degraded ballast have not been thoroughly examined; however it is believed that this ballast will not perform as well as new ballast, particularly when fouled.

    Furthermore, non-invasive detection of fouled ballast is often difficult in the field. The family of geophysical technologies has promise for enabling such detection. Electrical conductivity is one of these technologies that has not been thoroughly explored for this function. It is proposed that the change in electrical conductivity of ballast as it becomes fouled be investigated.

    It is proposed that the properties of recycled ballast from 3-5 sources be characterized with regard to their degree of degradation. The initial work on the first source of ballast was undertaken as a part of Phase 1. Strength, permeability, and electrical conductivity tests will be conducted on clean and fouled samples with the goal of relating the degree of fouling to reductions in the strength, drainage, and conductive properties of recycled ballast. The anticipated outcome is relationships between permeability and fouling, strength and fouling, and conductivity and fouling for each type of fouling
    Total Project Cost
    $ 61,490