2.3. Measurement of electrical properties of bentonite
The electrical property of interest in this study is the resistivity of bentonite. The following procedures to measure the resistivity of all 3 samples were adopted from [13]. A cubical box made of Perspex without the top lid with dimensions of 10cmx10cmx10cm was first constructed. Two opposite sides of the box were pasted with aluminum foil to provide a conductive surface for measurement purpose. The empty box is then weighed using digital weight scale with maximum weighing capacity of 30kg to obtain its mass. The box is then filled up completely with B1 and pressed with a 4.7kg iron cast bar sitting on top of a 9.6cmx9.6cm wood block for 30 minutes. This is to ensure a uniformly flattened and compressed form of sample inside the box. By achieving this, the packing density of the sample in powder form under known pressure can be deduced. Density of powder varies with different applied pressure.