Concrete Curing

[K8DO@aol.com]

For a large mass of concrete in the base of a tower, letting it dry on its
own will not result in significant loss of strength... how many ham towers
come down because the concrete base fragmented and allowed the tower to lever
over sideways, or sink into the ground?  ...  for thin flat slabs which are
expected to hold up cars, etc., and for building foundations, or machinery
foundations, or any use where the concrete is stressed closer to the maximum
values, then a controlled cure is necessary...so, in the ham tower world it
is not a problem... but, if it is not too much work to wet it a couple of
times a day and keep a vapor barrier over it, why not?...

Cement plus aggregate becomes concrete through the process of hydration of
the lime (a chemical reaction, not simply being physically wetted during the
mix)... for every molecule of lime to become properly hydrated into concrete
there must be adequate moisture present through out the 28 day curing
period... you can measure a 10% to 15% increase in strength for concrete that
is kept moist during this time, compared to concrete that is not... 

And there you have Concrete 101... you are entitled to 0.1 credits towards
getting your concrete PHD, for having read this...

Denny