New method for ageing resistant storage of argillaceous rock samples to achieve reproducible experimental results even after long intermediate storage times

In case of radioactive waste confinement indurated clays are potential host rocks as well as barrier rock formations. Therefore, laboratory tests on indurated clays together with physical modelling as well as numerical calculations are important topics of today’s international research work. Lots of laboratory experiments have been carried out in the past years at the Professorship for Waste Disposal and Geomechanics to determine the mechanical and hydraulic characteristics of argillaceous rocks, in particular with cylindrical samples. Due to increasing storage time, the properties of the rock exhibited at the time of the laboratory tests might not necessarily be reflective of the actual properties of the rock in situ that the sample is supposed to represent. Within long-term plastic bag storage of claystone core samples macroscopic damage was observed that negates the development of laboratory tests. This contribution deals with the experience of more than one year using a new method for ageing resistant storage of argillaceous rock samples to achieve reproducible experimental results even after long intermediate storage times. Investigated material properties are strength and deformability. A comparison between different types of storage with respect to mechanical properties is given, demonstrating the basic advantage of using pressure cells in the future to get reproducible data independent of storage times.