  The evolution of fractal surface structures with flattening of asperities was
investigated using isotropically roughened aluminium surfaces loaded in
compression. It was found that asperity amplitude, mean roughness and fractal
dimension decrease through increased compressive stress and number of loading
events. Of the samples tested, surfaces subjected to an increased number of
loading events exhibited the most significant surface deformation and were
observed to exhibit higher levels of static friction at an interface with a
single crystal flat quartz substrate. This suggests that the frequency of grain
reorganisation events in geomaterials plays an important role in the
development of intergranular friction. Fractal surfaces were numerically
modelled using Weierstrass- Mandelbrot based functions. From the study of
frictional interactions with rigid flat opposing surfaces it was apparent that
the effect of surface fractal dimension is more significant with increasing
dominance of adhesive mechanisms.
