Geotechnical Properties of Lime Stabilized Pyroclastic Soils

In the paper, some results of an extensive experimental investigation on lime stabilised Italian pyroclastic soils are presented and discussed. In their natural state, these materials present several complexities, starting with their mechanical behavior which is often at the transition between hard soils and weak rocks. These soils are very reactive with calcium oxide (CaO) provided by lime, the effectiveness of the stabilisation mainly depending on the amount of low alkali allumino-silicate glass phase. Nevertheless there is a lack of systematic studies on the suitability of pyroclastic soils to lime stabilisation, and the effects of the treatment parameters on the engineering properties of the stabilised material. Two pyroclastic soils have been considered in this study. The first is a sand with gravel belonging to a pyroclastic flow deposit of the Colli Albani volcanic complex, and the second is a silty sand originated by the late activity of the Somma-Vesuvius. The results on natural and lime stabilised samples allow to assess the suitability and the effectiveness of lime stabilisation.