Behaviour of unsealed stabilized road pavements using non-linear strength model

Applications of soil stabilization in unsealed road pavements are increasing being applied in Australia and worldwide. These include using standard stabilizers such as cement, flyash, polymers, resins, acids, as well as using non-standard stabilizers in the forms of enzymes. The pavement designs based on such stabilizers are predominantly based on either project experience or site specific laboratory and/or field tests based properties. The behaviour of the underlying materials, in particular partial saturation and non-linear nature, is often neglected for simplicity in the design approaches which are currently in-place. The current research investigates the behaviour of unsealed roads subjected to operational traffic using the unsaturated Coulomb-strength model. Firstly, laboratory experiments were conducted on the basis of clay soil to investigate the stabilized and non-stabilized strength properties. Having calibrated the model, 3-D FE analyses were conducted to predict the response of unsealed road pavement under traffic loads. The results showed that the response of stabilized road pavements using realistic non-linear strength envelop is substantially different from the traditional pavement response predictions. Thus, it is required to adopt partial saturation and soil non-linearity for more realistic assessments of stabilization contribution during design than are currently used.