The
hydrated product of the cement compound in a grain of cement adheres
firmly to
the unhydrated core of the grains of cement. This means that unhydrated cement
left in a grain of cement will not reduce the strength of cement mortar
or
concrete, as long as the products of hydration are well compacted.
Abrams
obtained strength of 280 MPa using
mixes with a w/c ratio of only 0.08.
At such
a low w/c ratio, only surface hydration of cement grains would have
taken place
& a considerable portion of cement grains must have remained in
unhydrated
state. Abrams could obtain the strength as he applied tremendous pressure to
obtain proper compaction of such a mixture.
