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Journal Articles Geotechnique Year : 2023

Drying effect on the microstructure of compacted salted silt

Zi Ying
  • Function : Author
Yu-Jun Cui
Myriam Duc

Abstract

This study investigates the drying-induced microstructure evolution of compacted silt with different salinities, using mercury intrusion porosimetry (MIP) and environmental scanning electron microscope (ESEM). The pore size distribution (PSD) of specimens compacted near optimum (w = 17%) exhibited bi-modal characteristics. Upon drying (w = 8%), the PSD changed to tri-modal pattern with appearance of a new nano-pore population. This suggested the development of nano-fissures which could occur in the clay fraction and at the interface between clay particles and silt/sand grains due to the clay shrinkage. With further drying (w = 3%), the nano-pores disappeared and the PSD recovered to bi-modal characteristics, suggesting that the created nano-fissures were enlarged until they became micro-fissures. The salinity seemed to decrease the frequency of the drying-induced micro-pores due to the enhanced mechanical strength of salted soil by the soil aggregation resulting from the compression of diffuse double layer and a possible cementation effect produced by precipitated salt. However, the salinity effect was relatively low, due to (i) the low clay fraction (15.7%) and the low activity clay minerals (illite, chlorite and kaolinite), (ii) the low specific surface area (24 m 2 /g) which limited the salinity effect on diffuse double layer.
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Dates and versions

hal-03573083 , version 1 (14-02-2022)

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Zi Ying, Yu-Jun Cui, Nadia Benahmed, Myriam Duc. Drying effect on the microstructure of compacted salted silt. Geotechnique, 2023, 73 (1), pp.62-70. ⟨10.1680/jgeot.20.P.319⟩. ⟨hal-03573083⟩
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