The UPC oedometer is a stainless steel cell designed to conduct 1-D tests on unsaturated specimens under controlled hydraulic (by using different techniques to impose the soil suction) and mechanical (through a diaphragm pressure that applies a controlled pneumatic loading) conditions. As for the vertical load, a piston attached to a membrane (in an upper chamber) is sitting on the top of the specimen, thus transferring the pressure to it. There are three type of porous stones that can be selected. A high permeability pore-stone consisting of concentric metallic rings, which makes it suitable for soil suction control using the vapor transfer technique (i.e. high suctions). Another base consists of a high air entry value (HAEV) ceramic plate, which is used for controlling the suction using the axis translation technique (i.e. low suction range). And the third one, combines a HAEV porous stone at the center of the base, with concentric (high permeability) metallic rings at the periphery, enabling conduction tests in unsaturated tests from low to high suction values (and vice versa). This apparatus is mainly used in this project to determine the swelling properties of the barrier materials at different suctions.