Microstructural and Mineralogical Evaluation of the Effectiveness of Mixing Treatments in Stabilized Clays

This paper shows and discusses the results of a comprehensive mineralogical and microstructural investigation carried out on several samples collected from diaphragm walls obtained treating a deposit of overconsolidated clay with the cutter soil mixing (CSM) technology, one of the most recent methods for deep mixing. To this purpose, scanning electron microscopy, X-ray powder diffraction analysis, mercury intrusion porosimetry, and X-ray computed micro-tomography were extensively used to measure soil properties at the micro-scale. In addition, unconfined compression tests and permeability tests were conducted to evaluate the effectiveness of CSM also at the macro-scale. The capability of CSM to treat cohesive soils seems to be confirmed by the experimental investigation carried out so far, considering, particularly, the degree of mixture homogeneity achieved at the end of the mixing procedure, together with the growth of several hydration products in the cemented matrix.