The expansive soils of south Texas have traditionally been stabilized with lime or Portland cement. As an alternative, a class F fly ash was tried to stabilize expansive soils obtained from within or the vicinity of Kleberg County in south Texas. Three groups of soil samples were made. The first group was stabilized with 20% by dry weight of Class F fly ash, the second group with 6% lime, and the third group with 10% Portland cement. The purpose of lime and cement stabilized samples was to have a basis of comparison for the effectiveness of fly ash stabilization. Methods used to evaluate the effectiveness of stabilization included grain size, plasticity index, unconfined compressive strength, and scanning electron microscopy. Laboratory test results showed that fly ash, lime, and cement stabilization were all effective in ameliorating the texture and plasticity of the soils by reducing the amount of clay size particles and the plasticity index. Portland cement was more effective followed by lime and fly ash stabilization in changing the texture and plasticity of the soils. The unconfined compressive strength of all soil samples were increased substantially as a result of stabilization. Again Portland cement imparted the highest level of strength to the soil. Electron micrographs of the stabilized samples showed the formation of a calcium-silicate- hydrate which is believed to be responsible for the increase in strength. For the covering abstract see IRRD 863991.


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  • Accession Number: 00663244
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • ISBN: 0-87262-986-4
  • Files: ITRD
  • Created Date: Aug 24 1994 12:00AM