In the paper the role of microstructural investigations in understanding the chemo-mechanical response of lime-treated soils has been evidenced. Two lime-treated clays of different mineralogy (namely kaolinite and Ca-montmorillonite) have been considered for this study. The time dependent mineralogical and microstructural changes induced by lime addition have been monitored at increasing curing time by means of X-Ray Diffraction (XRD), Thermo-Gravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) Mercury Intrusion Porosimetry (MIP). In the short term, flocculation phenomena due to the cation exchange reactions control the microstructural features of lime-treated kaolin. The low reactivity of kaolinite clay minerals to pozzolanic reactions was detected as a delay in precipitation of new hydrated phases. The chemo-physical evolution of lime-treated bentonite depends on the combined effect of cation exchange and pozzolanic reactions which develop with a comparable time scale. Results of micro-scale investigations have been directly linked to experimental evidences at volume scale of the samples, allowing the understanding of mechanical behaviour of treated clays as function of the chemo-physical evolution of clay-lime-water system.
Microstructural investigations as a key for understanding the chemo-mechanical response of lime-treated soils / Russo, G.. - In: RIVISTA ITALIANA DI GEOTECNICA. - ISSN 0557-1405. - 1(2019), pp. 100-114. [10.19199/2019.1.0557-1405.100]
Microstructural investigations as a key for understanding the chemo-mechanical response of lime-treated soils
Russo G.
2019
Abstract
In the paper the role of microstructural investigations in understanding the chemo-mechanical response of lime-treated soils has been evidenced. Two lime-treated clays of different mineralogy (namely kaolinite and Ca-montmorillonite) have been considered for this study. The time dependent mineralogical and microstructural changes induced by lime addition have been monitored at increasing curing time by means of X-Ray Diffraction (XRD), Thermo-Gravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) Mercury Intrusion Porosimetry (MIP). In the short term, flocculation phenomena due to the cation exchange reactions control the microstructural features of lime-treated kaolin. The low reactivity of kaolinite clay minerals to pozzolanic reactions was detected as a delay in precipitation of new hydrated phases. The chemo-physical evolution of lime-treated bentonite depends on the combined effect of cation exchange and pozzolanic reactions which develop with a comparable time scale. Results of micro-scale investigations have been directly linked to experimental evidences at volume scale of the samples, allowing the understanding of mechanical behaviour of treated clays as function of the chemo-physical evolution of clay-lime-water system.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.