Investigation of geotechnical properties of clay soils mixed with recycled nano carbon black

Recycled waste materials have been investigated in different ways in civil engineering applications and at these studies the usability of waste materials have been examined in concrete production, road construction and soil improvement. In this study, the effect of recycled nano carbon black (nano-CBr) on consistency limits and unconfined compressive strength properties of clayey soils was investigated. For this purpose, 4 different ratios (1%, 3%, 5% and 10%) nano-CBr were mixed to 3 different clay soils (White, Green and Red clays). In order to determine the mineralogical and chemical properties of mixtures, pH, TDS, X-Ray, SEM and contact angle tests were also performed. In this study, 1% nano-CBr ratio was generally determined as the limit value in all experiments. The consistency properties of the mixed samples have not significantly changed for the red and green clay but have importantly affected the white clay properties. Based on the 1% nano-CBr ratio, the unconfined compressive strength (UCS) values of all mixed samples increased. Addition of super hydrophobic nano-CBr to clay soils, turned clay soils into a hydrophobic material, is resulting in an increase in the contact angle values. On the other hand, pH values did not show a significant change with the increase of the nano-CBr ratio. The total dissolved solids (TDS) measurements showed a series of rise and fall steps with the increase of nano-CBr ratio and showed a tendency to stabilize at 10% nano-CBr ratio.