Resilient Modulus of Freeze-Thaw Affected Granular Soils for Pavement Design and Evaluation. Part 1. Laboratory Tests on Soils from Winchendon, Massachusetts, Test Sections,
COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH
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This work is the first of a series of four reports about laboratory and field testing of various granular road and airfield subgrades. This report details the acquisition, testing and analysis of six soils from a test site in Winchendon, Massachusetts. Repeated load triaxial tests were done on frozen and thawed soils to characterize the variations in their resilient properties through out the seasons. Linear regression yielded empirical equations relating the resilient modulus to applied stress, unfrozen water content for frozen soils, moisture tension for thawed soils and density. Equipment and test procedures given in detail were developed that allowed simulation in the laboratory of the gradual recovery of stiffness that occurs in the field after thawing. The resilient moduli were strongly dependent on soil state, dropping at least two orders of magnitude upon thawing. For all soils the moduli increased with increasing confining stress, generally decreased with increasing principal stress ratio, and increased with increasing moisture tension levels. The resilient moduli increased by a factor of approximately two as the materials recovered from the effects of a freeze-thaw cycle. This recovery process is well modeled as a function of soil moisture tension level. The stress sensitivity did not appear to be a function of the soil moisture tension level. The report also includes tabulations of all the repeated load triaxial test data.
- Soil Mechanics
- Civil Engineering
- Test Facilities, Equipment and Methods