Civil Engineering Reference
In-Depth Information
break, put up shuttering if necessary, and
work out your levels. Then mix the limecrete
(see below) and lay it! Keep the mix fairly
dry as too much water will make it crack, but
level it and float it just like a concrete slab.
will become much more sticky and workable
without adding more water. Once you've got
the right consistency - not sloppy but not
crumbling apart either - then you will know
from the mark on your bucket how much
water you've used, and can re-mark your
bucket to suit.
Measuring quantities
Mixing
Work towards using either a whole bag or
a half bag of lime as your measure, then
this does not have to be tipped out of the
bag each time but can be put into the mixer
straight from the bag.
As the materials are dry, they can be mixed
in a cement mixer. A small cement mixer
will usually take half a bag of lime to three
volumes of sand, but a larger one might
take double this. Whatever mixing method
you use, all ingredients must be thoroughly
mixed together - all lime benefits from long
mixing.
Wheelbarrows marked with a marker
pen (very important!)
work well. Start by
working out what volume half a bag of lime
fills, mark this on the barrow, then add the
other half and mark this as well, so you
know what volume both a half and a full
bag of lime take up. You'll need three times
as much aggregate as lime for the mix, so
fill one barrow to the mark you made to
show the volume of lime, then offload into
another barrow to make sure that both are
marked to the same volume.
•
Get all materials ready in the right
quantities.
•
Start the mixer.
•
Add some sand.
•
Add some water.
Another option, once you've marked up
the volume that lime takes up, is to fill this
volume with sand and then move the sand
into buckets, so then you know how many
buckets are needed for either a full bag or a
half bag of lime.
•
Add some lime.
•
Continue adding, making sure that more
sand goes in than lime, and that the
mix stays wet until the last lot of lime is
added. Remember that it will get stickier
as it mixes so be careful not to add too
much water!
Once the volumes are worked out, you
will need to work out the volume of water
needed per mix. Fill a bucket and mark its
level, then add this cautiously to the mix
(see right), taking care not to add too much.
It should be fairly dry at the point where
all the sand and lime are mixed together,
because after 15 minutes of more mixing it
•
Once all the ingredients are fully mixed,
continue mixing for 15 minutes before
tipping out. This makes the mix much
more workable and sticky.
