Microstructure insights in mechanical improvement of a lime-stabilised pyroclastic soil

摘要

A large experimental work has been developed on a pyroclastic soil from Southern Italy to showrnits suitability to lime stabilisation and the effectiveness of the treatment. Some of the results obtained by meansrnof oedometer tests, including conventional loading paths as well as wetting paths, on both not treated and limernstabilised samples have been presented in the paper. The beneficial effects of the mechanical improvementrninduced after the addition of lime have been linked to the chemical–physical evolution of the system, withrnparticular reference to the short term. Microstructural analyses (XRD, DTA, FTIR) performed on not treated andrnstabilised samples showed that ionic exchange is not expected for the pyroclastic soil and that the ongoing ofrnpozzolanic reactions develop since the very short term in the system. The formation of calcium Silicate Hydratesrn(CSH) and Calcium Aluminate Hydrates (CAH) is responsible for the mechanical improvement of the stabilisedrnsoil, with particular reference to the structural collapse behaviour.