Investigating the Microstructure of Compacted Crushed Callovo-Oxfordian Argillite

Some aspects of the macroscopic geotechnical behavior of compacted soils are highly related to their microstructure. This paper presents a qualitative and quantitative microstructure investigation of compacted samples made up of crushed Callovo-Oxfordian argillite. This material is considered as being possibly used as backfill material in radioactive waste disposal at great depth. Scanning electron microscopy and mercury intrusion porosimetry technique were employed to determine the fabric and pore size distribution properties of the samples. The results show that an increase of the compaction effort only results in the reduction of the inter-aggregates porosity. After wetting, the sample displays a relative homogenous microstructure with a decrease in the macropores population.