WA (see Fig. 4) and AP (see Fig. 5) vary as a linear function of residue content.
Both values increased with increasing amount of SMC.
WA rises up to 22.5% and according to ASTM C62-13a [48]its use as facing brick,
is limited just for the case of moderate and/or negligible weathering,
therefore when sewerage weathering is expected FCBs made by adding 17% of SMC must be coated.
Previous research [31] has shown same values of WA for similar percentage of additive (around 23% for 15% of SMC added).