Characterization of changes in soil porous system by gamma-ray tomography

In this study the use of a first generation computed tomography (CT) scanner to evaluate changes in total porosity and bulk density of a porous medium (a soil sample) submitted to wetting and drying (W–D) cycles is presented. In nature, soils are commonly submitted to W–D cycles as they are exposed to the hydrologic cycle. Also, a large number of procedures conducted at laboratory levels frequently expose soils to W–D cycles. The methodology using the CT technique was applied to investigate a Brazilian clayey soil submitted to consecutive W–D cycles. The obtained results showed that the use of CT permitted a detailed evaluation of important changes in soil bulk density and total porosity due to these cycles, something that cannot be achieved by the traditional methods used to investigate these physical parameters.