Micro-structural characteristics deterioration of intact loess under acid and saline solutions and resultant macro-mechanical properties

When exposed to chemicals, the micro-structural evolution of the loess and the impacts on the macro-mechanical properties are considered crucial for contaminated land reclamation. In this study, the micro-structural characteristics of the loess specimens that are exposed to acetic acid or sodium sulfate, are studied using scanning electron microscopy, X-ray diffraction, and energy dispersive spectroscopy analyses. Further, their macromechanical properties are determined by direct shear tests. The corrosion of the cement between particles under acetic acid environments and the salt-induced swelling under saline conditions play an important role in the micro-structural deterioration. The cohesion and friction angle for the wetted loess are about 16 kPa and 19 degrees respectively, while for the acetic acid-contamianted loess, they reduce to 10 kPa and 15 degrees respectively. They, for the sodium sulfate-contaminated loess, reduce further to below 10 kPa and 13 degrees respectively. The macromechanical properties show good correspondence with the micro-structural deterioration.

Automated summary

The micro-structural evolution of loess and its impact on macro-mechanical properties when exposed to chemicals were studied. The corrosion of cement between particles under acetic acid environments and salt-induced swelling under saline conditions played crucial roles in the micro-structural deterioration.