Loading characteristics of a tertiary clay and implications for road pavement design

  • Smith R. B. 
General Papers


A Tertiary clay was subjected to California Bearing Ratio testing and repeated load testing. X-ray diffraction showed that the clay fraction was quartz-rich with minor amounts of goethite (5–10%). The clay component consisted of mainly kaolinite (55%) and a mixed layer expandable clay (45%) with a minor amount of illite. The study showed that bearing capacity of the material was very sensitive to the moulded moisture content and relative density at compaction. Similarly the repeated loading characteristics at the stress levels likely to be experienced in a road subgrade indicated that the performance under repeated loading was also extremely sensitive to the moulded moisture content and relative density. The implications for road pavement design of this material are also discussed.


California Bearing Ratio Resilient Modulus Pavement Design Relative Compaction Standard Compaction 

Capacité portante d'une argile tertiaire et conséquences sur la conception de la chaussée


Une argile tertiaire est soumise à des essais C.B.R. et à des essais de chargement répétés. La diffraction X a montré que la fraction argileuse était riche en quartz, avec un peu de gœthite (5–10%). La phase argileuse est composée surtout de kaolinite (55%) et d'interstratifiés gonflants (45%) avec des traces d'illite. L'étude a montré que la capacité portante du matériau est très sensible à la teneur en eau et à la densité relative au compactage. De la même façon les caractéristiques de chargement répétés aux niveaux de contraintes susceptibles d'être rencontrés dans une sous-couche de chaussée indiquent que les performances sous chargements répétés sont également très sensibles à la teneur en eau et à la masse volumique réelle. L'auteur discute l'influence de l'utilisation d'un tel matériau sur la conception de la chaussée.


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Copyright information

© International Association of Engineering Geology 1988

Authors and Affiliations

  • Smith R. B. 
    • 1
  1. 1.Parramatta DivisionDepartment of Main Roads NSWParramattaAustralia

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