and volume of isolated pore
space (pores that are not connected to the external surface). The
values show that higher total porosity was obtained in M2 and
M4, 21.4 and 21.2, respectively, but specimen M4 reached the
highest open (connected) porosity (Fig. 4), which is crucial for
the permeability of pervious concrete. Compared to specimens
M3 and M5 in which the same proportions of material were used,
only the aggregate was different (slag instead of dolomite) in M2 and M4.