Ingredients. |
12 x 55 lb bags (660 lbs) NHL 5 per cubic yard (or
27 cubic feet) of aggregates consisting of 1 part
sharp concrete sand: 2 parts 1/2" to 3/4" aggregate
and approximately 2.5 to 3 gallons of water per 55
lbs. of lime. |
Mixing. | Mix dry to achieve a uniform color in a pan mixer
or roller pan mill, slowly add clean water until
semi dry, just sufficient to allow mix to bind when
squeezed in hand. Free fall mixers can cause
balling. |
Substrate. |
Lime concrete should be laid on a compacted sub
base of clean 2" to 3" clean screened
aggregate (# 2 Stone)(minimum 6" thick base). The
greater the thickness of the sub-base, the better the
insulation properties. Damp proof membranes are
not necessary. Lime concrete can be laid directly
on to sub soils that contain clays that have had a
3/4" layer of NHL 5 hydraulic lime rotovated into
them and compacted (sub soils should be analysed
before proceeding). Damp proof membranes are
not necessary. |
Laying. |
The concrete is placed in a single layer of 2", or 2
layers of 2" to make a 4" layer depending on
purpose. 2" will be sufficient for normal foot
traffic and 4" for light vehicular traffic. It should
be well rammed either by hand or with a
mechanical compaction plate to the desired level.
Form mechanical key between layers. Lay green
on green (within 24 hours). |
Finishing. | Exposed aggregate finish: after 24 hours the
surface of the compacted and levelled concrete is
brushed with a stiff yard broom initially, then a
soft brush. On large areas it may be necessary to
treat the surface of freshly compacted concrete
with an inhibitor to hold back the set.
A trial panel should always be done. |
Curing | Light mist with clean water for 72 hours or more
depending on conditions.
Never lay on a frosted or exceedingly hot surface.
Protect from extreme heat, freezing, excessive
wind, strong direct sunlight and rain. Ambient
temperature range should be
40oF-85oF with low to average humidity. |
Protection. | Foot traffic should be avoided for 7 - 10 days
depending on the weather. Cover with protective
walkways 12 hours after placing. These should
remain in place for at least 2-3 weeks or longer if
possible. |