Mechanical properties of the soft soil stabilized with soda residue and ground granulated blast furnace slag under the erosion environment

Soda residue (SR) and ground granulated blast furnace slag (GGBS) can be used as effective stabilizer for soft soil. However, the behavior of the SR-GGBS stabilized soil in the presence of soaking is seldom examined. In order to reveal the performance of SR-GGBS stabilized soft soil under the erosion environment, visual observations and unconfined compressive strength tests are conducted, and the scanning electron microscopy is used to discuss the mechanism. The results indicate that the samples in tap water or 30 g/L NaCl solution are intact, and the density increases with the soaking time. In 15 g/L MgSO4 solution or mixed solution, the samples are eroded obviously, and the volume, mass and density decrease with the soaking time. When the soaking time increases from 28 d to 42 d, the unconfined compressive strength of the samples in tap water increases, and the strength of the samples in solution remains unchanged. The soaking results in the increase of ductility and decrease of deformation resistance. At the same soaking time, the strength of the samples in MgSO4 solution or mixed solution is about half that in tap water or NaCl solution. The ability to resist deformation is also weak for the samples in MgSO4 solution or mixed solution. The formation of hydration products such as ettringite and calcium chloraluminate hydrate in SR-GGBS stabilized soil is helpfull to resist to NaCl erosion, while its resistance to MgSO4 erosion is weak due to the micro-cracks and loose structure. The results will contribute to the use of SR and GGBS as stabilizers for soft soil in the complex environment.