Polished Stone Value Test and its relationship with petrographic parameters (hardness contrast and modal composition) and surface micro-roughness in natural and artificial aggregates

The goal of this work was first to establish the relationships between the PSV values and the microstructural and mineralogical features of the aggregates and surface micro-roughness, and then to establish the behavioural differences between natural and artificial aggregates. The results obtained indicate that the surface micro-roughness and the different PSV values of the natural aggregates are strongly governed by the existence of minerals with different degrees of hardness, together with the proportion of these minerals. In contrast, the different degree of porosity in artificial aggregates (a furnace slag) was seen to be responsible for its high surface micro-roughness and PSV values. Finally, the PSV and a petrographic parameter (Overall Hardness Contrast, Delta H) were seen to be related by an exponential curve (PSV=39.726 Delta H-0.057) with an extremely good fit, providing a good tool to estimate PSVs in natural and artificial aggregates from petrographic parameters.