NEW APPROACH TO DETERMINATION OF EXPANSION INDEX

An alternative approach is presented to the rapid determination of expansion index (EI) based on the electrical properties of soil. The magnitude of dielectric dispersion on 16 natural soils from various parts of California was determined on a saturated soil water paste prepared at the liquid limit of soil. Expansion index values were determined. The test results indicate that the plasticity index (PI) correlates with EI in the range of PI of about 15-25, but in the range of low and high values of PI a large deviation from a linear relationship is obtained. The linear relationship between EI and the magnitude of dielectric dispersion for all values of the latter is an indication of the significance of classifying soils using the magnitude of dielectric dispersion as a measure of the amount and type of clay. It is then shown that EI can be determined from a knowledge of the magnitude dielectric dispersion. An alternative classification of expansive soils based on the magnitude of dielectric dispersion is suggested and compared with expansion index classification proposed by Karzynski. The magnitude of dielectric dispersion of soil can be determined in an undisturbed or remolded state in about 1/2 hr. The determination requires a radio-frequency bridge and the calculation involved is very simple.

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00127115
  • Record Type: Publication
  • Report/Paper Numbers: ASCE #11538 Proceeding
  • Files: TRIS
  • Created Date: Dec 29 1975 12:00AM