DRYING SHRINKAGE PROBLEMS IN HIGH PI SUBGRADE SOILS

Abstract

The main objective of this study was to investigate the longitudinal cracking in pavements due to drying shrinkage of high PI subgrade soils. The study involved laboartory soil testing and modeling. The shrinkage cracks usually occur within the vicinity of the edge of the pavement where moisture boundary conditions play a significant role in the behavior of expansive subgrade soils. The study investigated the shrinkage problems in pavement subgrade soils at four sites in Oklahoma. The soil specimens collected from the sites were tested for the basic index properties as well as soil suction and unsaturated diffusivity measurements. Various ranges of the test results have been implemented in suction profile and tensile stress prediction models for evaluating the typical suction changes and the corresponding tensile stresses in subgrade soils.