ABSTRACT
Ballast deforms and degrades progressively under heavy cyclic loading. The degradation of ballast particles can occur in several ways: grinding off of small-scale asperities (abrasion) in which resulting fines cause fouling and reduce drainage; breaking of fragments and angular projections, which influence the initial settlement; and fracturing or splitting of individual particles. This breakage is responsible for the long-term stability and safety of the track.
