Pore fluid salinity effects on post-stabilization performance of cement-treated Marl

Abstract

Soil improvement using chemical admixtures has been extensively investigated in the recent past and these admixtures are abundantly being used on various construction projects. However, there is a need to elucidate the long-term performance of stabilized geomaterials under aggressive pore fluid environments such as high salinity of groundwater in coastal areas. This study presents the effects of the concentration of pore fluid salinity on the post-stabilization behavior of cement-treated Marl specimens to brine solution from Sabkha deposits and rejected water from a water treatment plant. Unconfined compressive strength (UCS), mineralogy, chemical, and microstructural evaluations have been carried out in this regard. minerals like albite and muscovite completely leached out of the samples after 28 days of soaking in a saline environment. A new mineral Attapulgite was formed at various concentration levels of the pore fluid. Significant changes in the chemical composition were also observed in various phases of the experiments. Moreover, at all salinity levels, the UCS initially increased to a maximum of 75 % which later reduced to a value less than the original strength whereas the elastic modulus (E50) increased as the soaking period progressed. Lastly, it is emphasized that the engineering properties of treated soils exposed to aggressive pore fluids should be carefully assessed for a reliable prediction of the long-term performance of geotechnical structures.

Keywords

• Marl
• Cement-stabilization
• Pore salinity
• Strength
• Microstructure
• Mineralogy