CONCRETE
BASICS:
There are two ways to go with concrete for the walkway: you can
order it from an already-mixed company, or you can mix it yourself.
Since a walk way is relatively small, you may opt to mix the concrete
yourself, although you should know that the mixing procedure is
hot and heavy work. If you
are placing the walk in sections, you must install stop boards that
will divide the form into a smaller working space. This technique
is best if you are mixing the concrete from scratch. Stop boards
also brace forms for stability. You can cut control joints in the
slab by slicing the concrete while it is still wet, but floated
or troweled, with the end of a trowel. Then use a groover tool to
smooth the cut. Put in expansion joints with expansion strips where
the walk butts against a solid surface such as a curb.
To order
from an already-mixed company, tell the order-taker the length,
width, and depth of the project. They will figure the number of
cubic yards of concrete you need. Be ready for the concrete truck;
the driver will dump it and run and you'll have to be prepared to
level the mixture, fill holes, remove high spots, and so on. Have
a couple of helpers handy; you don't have too much working time
with concrete.
Concrete
Formulas-
If you decide to mix the concrete yourself, look at chart below
for mixig ratios.
Air-entrained
concrete is needed in areas where concrete must withstand freezing
and thawing temperature shifts and deicing treatments. Air entrainment
is a process of introducing millions of microscopic air bubbles
into the concrete. The air bubbles permit enough space for the absorbed
water to expand when the water freezes, so the slab doesn't crack
or break apart. Air-entrained concrete is also easier to place and
finish than is regular concrete, because the tiny air bubbles act
as lubricants while the concrete is still plastic. Air-entrained
Portland cement is available in home center and building material
outlets.
Concrete Mixing Ratios:
