Dupré Vermiculite
replaces out-moded alternatives to give permanent
and trouble-free bases for vinyl lined pools, that
insulate and prevent puncture of the liner.
Ingredients needed
The constituents of
Vermiculite concrete for pool bases are simply:
Vermiculite
Ordinary Portland cement
Plasticiser and Clean
Water
The mix proportions can
be varied but the most commonly used preparations
are:
2 bags Vermiculite to 2
bags Cement
3 bags Vermiculite to 2
bags Cement
i.e. 6:1 and 8:1 by
volume respectively, the 6:1 giving a "firm"
concrete base and the 8:1 a "soft" base.
The addition of, up to, 1 part of smooth sand will
improve initial strength and surface finish but will
impair resilience and abrasion resistance. You can
make trial batches to see which best suits site
conditions.
Mixing
The mixing is carried
out in an ordinary drum mixer as follows:
The Vermiculite and
cement should be mixed dry for one minute, after
which the water with Plasticiser is added - this
being thrown to the back of the mixer. Mixing will
be more efficient if the drum is tilted forward. Wet
mixing should be complete in a couple of minutes. Do
not wet mix for too long. Consistently satisfactory
results are not obtainable by hand mixing. 12 bags
of Vermiculite will produce approximately 1m3
of concrete.