Behavior of a Simulated Collapsible Soil Modified with XPS-Cement Mixtures

The overall structure of collapsible soils collapses by moister absorption. This is also makes their stabilization and modification necessary with an additive which is often cement. However, a new modification additive, XPS-Cement Mixture, was utilized in this study in order to improve compression characteristics of a simulated collapsible soil. The soil used in this study is named ML in the unified classification system and the reason why it was used is because of its low plasticity index. This parameter is one of the most essential factors of collapsible soils so that makes their stabilization necessary. In the present study, the collapsibility potential (CP) of a simulated modified soil was evaluated by adding different percentage of cement to it. More than 120 tests were carried out in a three-cell consolidation apparatus. Based on information obtained, by adding XPS-Cement mixture up to a specified content CP decreases. However, by further addition no remarkable decrease would be observed. In addition, changes in the collapsibility index were investigated versus the changes in the vertical stress for two types of samples; modeled natural soil and improved soil. Of particular significance of this part is the result which exhibits the drastic effect of high levels of stress on the compression behavior of collapsible soils.