CHARACTERIZATION OF SUBGRADE SOILS AT SIMULATED FIELD MOISTURE

It is important to assess the strength characteristics of subgrade soils at equilibrium moisture content (EMC), generally a few percentage points wet of optimum moisture content (OMC). Investigation of the effect of saturation--degree and mode--above OMC on the resilient modulus (M sub R) of laboratory compacted subgrade soils is the topic of this paper. Three modes of saturating (wetting) are investigated: (a) capillary saturating, (b) vacuum saturating, and (c) molding wet of optimum. EMC and 96% saturation are the two different degrees of saturation considered. The M sub R of soil samples, both coarse- and fine-grain, are evaluated for different combinations of degree of saturation and saturating mode. The test results indicate that the degree of saturation above OMC has a nominal effect (20%) on M sub R of coarse-grain soils, whereas it has a severe effect (50 to 75% decrease) on the M sub R of fine-grain soils. Another finding is that both degree of saturation and saturating mode affect the M sub R of fine-grain soils. For interpretation of the results, particularly how M sub R is affected by saturation, the four-phase concept for unsaturated soils is used.

Language

  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 21-27
  • Monograph Title: Environmental moisture effects on transportation facilities and nonearth materials' thermal effects on pavements
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00712976
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Oct 10 1995 12:00AM