- Q.I have talked to eight
different concrete subcontractors, and four have
claimed that concrete expands as it sets and four claim
that it shrinks. Which is correct?
A.Concrete shrinks as
it cures, and will continue to shrink very slightly
at a decreasing rate over time. There are special
grouts used by millwrights for setting machinery
which do expand when they cure, but these are not
ordinarily used in construction.