The PL values of the mixtures containing granite powder,
namely, B, C, E, F, and H, were almost equal to those of the mixtures
that did not contain granite powder, namely, A, D, and G. The PL of a
mixture is used to determine the amount of water to be added to it.
However, in practice, the amount of water used is always lower
than the calculated value. Some mixtures had zero PI; however, this
did not prevent their extrusion.