Abstract: The present invention contemplates a gyratory compaction apparatus for creating compression and shear forces in a sample material, the apparatus using a single roller to accomplish the gyration comprising a hollow cylinder mold including first and second end plates in slidable engagement with the mold at respective first and second open ends, with a chamber inside the mold for receiving the sample material, a support frame having an interior suitable for receiving the mold therein, a compression mechanism for compressing the sample material, and a gyratory assembly comprising a rotational drive motor having a drive shaft aligned along the longitudinal axis of the support frame interior, a cam mounted at the end of the drive shaft, a gyratory plate having an inner housing for encompassing and operably engaging the cam including a spring biased plunger operably engaging the cam and a first outer angular contact bearing for operably engaging the mold inner surface and a driven plate operably mounted to the suppo