Shrinkage strain characterization of expansive soils using digital imaging technology

Summary The main objective of this chapter was to describe various shrinkage strain estimation methods followed in geotechnical practice and then introduce a novel method of estimating shrinkage volume changes in soils by testing a cylindrical specimen prepared at various expected moisture contents in the field. The procedure uses digital image analyses, which eliminates operator dependency on test measurements. Two separate experimental studies were presented here which cover linear and three-dimensional volumetric shrinkage test measurements conducted on natural and stabilized expansive clayey soils. Variations in measurements indicated larger shrinkage strains with digital when compared to manual measurements, indicating erroneous characterization of the severity nature of the soil with manual measurements. Major findings from test methods, repeatability, reliability, and future research needs were also addressed.