Abstract:
A sustainable demand of good quality materials for construction, together with environmental restrictions on public works, makes Deep Soil Mixing (DSM) a very appealing solution for infrastructure development. The simple principle of mixing cement with in situ soil, instead of adding quarried aggregates, enables to reinforce with columns unsuitable ground making it able to host application otherwise too costly or impossible. However, the effectiveness of treatments relies on the capability of operators to infer amenable mechanical properties to the soil, an issue that becomes often critical for clays due to the difficulty of fragmenting soil clogs and the imperfect soil-cement mingling. The present study reports the results of a laboratory-based program aimed at testing the effectiveness of an additive traditionally used for tunneling purposes, that reduces the adhesion and clogging tendency of clayey particles. Experiments particularly addressed to quantify the performance in DSM application, are performed on two reference materials, a kaolinite and a smectite, mixed with different dosages of water, cement and additive. The variation of the mechanical properties induced by the additive is herein analyzed performing rheological and unconfined compressive (UCS) tests. Micromechanical tests are performed as well to interpret the positive role of the additive.