A Laboratory Methodological Proposal for “Geotechnical Lime Stabilization of A-4 Soils”

This paper establish the beginning of a research process regarding the behavior of soils stabilized with lime. Generally, the geotechnical practice of soils stabilized with lime requires a first step conducted in the laboratory, to attest the features of “natural soils” in order to improve their behavior in term of geotechnical performance and, a second step, carried out onsite with experimental test fields, in order to verify the benefit obtained by the use of lime treatments. The topic of this research focuses on the first step above described. In order to provide geotechnical laboratory tests useful to our purpose, A-4 soils (according to HRB classification) and CL-ML (according to USCS soils classification) were tested. These soils show a large distribution in the Piedmont Po Plain (NW Italy): they outcrop in correspondence to terraced alluvial fans linked to alpine watercourses and are generally applied for stabilization with lime for foundation structures and pavements. Additionally, these soils are mainly inorganic with a marked tendency towards sandy silt soils with the presence of gravel. The presence of gravel results on a greater strain hardening in the behavior of shear strength of soils. Finally, in support of geotechnicians, who have to draw up specifications, a systematized laboratory methodology to follow for A-4 soils stabilization with lime is here reported and a detailed analyses of mechanical behavior obtained on “soil-lime-water mixtures” is described.