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

Christie A. Mahaffey, Michael Peterson, C. Wayne McIlwraith

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


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.

Original languageEnglish
Pages (from-to)21-27
Number of pages7
JournalSports Engineering
Issue number1
StatePublished - Mar 2012

Bibliographical note

Funding Information:
Acknowledgments 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.


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

ASJC Scopus subject areas

  • Biomedical Engineering
  • Modeling and Simulation
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation
  • Mechanics of Materials
  • Mechanical Engineering


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