Impact of Portland cement and lime on the stabilization and shear strength characteristics of contaminated clay

ABSTRACT

Chemical treatment with cementitious materials is a common and economic solution to improving the mechanical behavior of contaminated clay soil. In this research, Portland cement and lime were used to treat kaolinite contaminated with anthracene and glycerol. The samples were cured for 7 days and their unconfined compressive strength (UCS) was determined. The results showed that the UCS of kaolinite contaminated with anthracene and glycerol was less than that of clean clay. In samples contaminated with anthracene, treatment with 3% Portland cement was roughly equivalent to that of 10% lime. In samples contaminated with glycerol, treatment with 9% Portland cement was equivalent to that of 10% lime. The results were verified by scanning electron microscopy. Triaxial unconsolidated undrained testing was carried out at different confining pressures on samples having similar UCS values. The results revealed that anthracene and glycerol contamination reduced the ultimate deviatoric stress and that the maximum deviatoric stress decreased as the amount of contamination increased. Also, the cohesion and internal friction angle decreased as the amounts of anthracene and glycerol increased. This could be attributed to the polarity, dielectric constant and viscosity of the organic material. All Portland cement–treated and lime–treated samples at the different confining pressures had higher peak shear strength values than the untreated ones. The maximum triaxial compression strength of specimens with equivalent UCS values was similar at low confining pressures, but an increase in confinement caused the Portland cement to perform better.

KEYWORDS:

• Kaolinite
• hydrocarbon contamination
• stabilization
• triaxial tests
• shear strength
• scanning electron microscopy

Disclosure statement

No potential conflict of interest was reported by the author(s).