Sports Engineering

, Volume 15, Issue 1, pp 21–27 | Cite as

Archetypes in Thoroughbred dirt racetracks regarding track design, clay mineralogy, and climate

  • Christie A. Mahaffey
  • Michael Peterson
  • C. Wayne McIlwraith
Original Article


In Thoroughbred dirt racetracks, clay content plays a critical role in moisture management and influences mechanical properties. We hypothesized that different dirt track designs developed in response to the track materials used, particularly the clay content of the material. These designs are in turn a function of the local climate, in particular the amount of rainfall and the evaporation rate. X-ray diffraction makes it possible to determine whole rock and clay mineralogy for 26 tracks that were assigned to one of three track designs: shallow sand (SS), false base (FB), or false base with a pad (FBP). Results demonstrate that SS tracks occur in areas with the highest annual precipitation and have the lowest average clay content, whereas FBP tracks have the lowest annual precipitation and the highest average clay content. FB tracks have intermediate levels of precipitation and clay relative to other track styles. Understanding the effects of clay minerals in dirt and how different racetrack designs have evolved to handle differing levels of clay and moisture can aid in quantifying track maintenance decisions.


Clay mineralogy X-ray diffraction (XRD) Dirt racetracks Thoroughbred racing surface 



X-ray diffraction


Shallow sand


False base


False base with a pad



XRD samples were separated at the Racing Surfaces Testing Laboratory with analysis and surface sample preparation by James P. Talbot, K/T GeoServices, Inc. Funding was provided by the Grayson-Jockey Club Research Foundation, the founding sponsors of the Racing Surfaces Testing Laboratory and the Churchill Downs Incorporated Safety from Start to Finish Initiative.


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Copyright information

© International Sports Engineering Association 2012

Authors and Affiliations

  • Christie A. Mahaffey
    • 1
    • 2
  • Michael Peterson
    • 1
    • 2
  • C. Wayne McIlwraith
    • 2
    • 3
  1. 1.Mechanical EngineeringUniversity of MaineOronoUSA
  2. 2.Racing Surfaces Testing LaboratoryOronoUSA
  3. 3.Department of Clinical SciencesColorado State UniversityFort CollinsUSA

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