Hydraulic conductivity of clay mixed with nanomaterials

Abstract

The focus of this note is to investigate the hydraulic conductivity behavior of clay mixed with nanomaterials. Two different nanomaterials — namely, gamma-aluminum oxide powder (γ-Al 2 O 3 ) and nano-copper oxide (CuO) — were selected and mixed with clay at different percentages (i.e., 2%, 4%, and 6%). Hydraulic conductivity tests were carried out in a flexible wall permeameter following the ASTM D5084 standard. Mercury intrusion porosimetry (MIP) tests were also carried out to determine the pore-size distribution. At 2% of γ-Al 2 O 3 and nano-CuO, the hydraulic conductivity of clay decreased 30% and 45%, respectively. As the proportion of the nanomaterial increases, the reduction of hydraulic conductivity becomes less prominent as flow paths devoid of nanomaterials are unlikely. Reduction of hydraulic conductivity is due to the pores of clay being clogged by the nanomaterial. Pore-size distribution curves show that the largest pore size reduced by 20% when clay was mixed with 4% nano-CuO.