Effect of Activated Carbon as a Stabilizer on Geotechnical and Microstructural Properties of Clayey Sand Soil

Currently, chemical stabilization with various additives is a common method for improving the engineering properties of different soils. However, environmental and financial factors are also crucial in determining the types of additives used. The present study evaluates the effects of activated carbon (AC) as an environmentally friendly and cost-effective material on the geotechnical and microstructural properties of a clayey sand (SC). For this purpose, the AC as a stabilizer was added to the SC specimens at mass contents of ۱, ۲, ۳, ۴, and ۵% and unconfined compressive strength (UCS) and pH tests were performed at curing ages of zero, ۷, ۱۴, and ۲۸ days. Direct shear and permeability tests were also conducted on the specimens immediately after addition of the AC contents. Results showed that increasing the AC content upto ۴% and extending the curing age to ۲۸ days enhanced the UCS of SC by up to ۱۹۶%. All the stabilized specimens showed a significant decrease in pH level compared to the non-stabilized specimen, with increasing curing age from zero to later stages. However, the curing age had no significant effect on the pH of the stabilized specimens. The shear strength increased with the addition of up to ۱% AC, then decreased. The permeability of SC decreased as the AC content increased. Also, microstructural analyses were conducted using scanning electron microscopy (SEM) on both non-stabilized and stabilized specimens with ۴% AC at curing ages of zero and ۲۸ days. SEM revealed a flocculated microstructure in the stabilized specimens, mainly due to ion exchange, particularly at the ۲۸-day curing age.

کلیدواژه ها:

Activated carbon ، Clayey Sand ، UCS ، Shear strength ، Permeability ، SEM