Thin sections were elaborated and described both in mixtures and in
individual materials. Further, thin sections were photographed (20 photographs)
and their image analyzed, to quantify in situ porosity. Our findings showed that
bulk material present unsorted particles with high porosity variability (between 44-
79%) within the same mixture; hence, these data correlate with the high variability
of their physical properties. Also, each particle size within the same material
(organic or inorganic) are perfectly sorted, but with different types of pores:
compound packing voids (3.36 mm), vughs (1 mm), and close packing voids
(0.25 mm). Consequently, physical properties vary in each particle size analyzed.
Finally, in mixtures with different ratio, porosity variability is low, because only
complex packing voids occur in these; however, physical properties vary according
to dominance of the type of pore (storage or percolation). Micromorfological and
image analysis are recommended in the studies of mixtures of materials in order to
understand the physical properties of the substrates. It is necessary to use the same
particle size in individual or mixture materials to guarantee reproducibility of their
physical properties.