How To Build A Spray-In-Place Concrete Fence - Monolithic

extremely valid measurement for concrete
in the 5, 6 sack range with 3/4 or
larger aggregate.
Compressive Strength Tests
Compressive strengths in the
conventional concrete industries are
performed by breaking cylinders that
have been filled and set aside for that
purpose. A good correlation between
a series of cylinders is about 20%.
Unfortunately shotcrete doesn’t test
very well in cylinders unless they
are special shotcrete cylinders which
are hard to come by. The most valid
system for testing shotcrete seems to
be the Windsor probe or spraying a 2”
thickness that is later cubed and tested.
Cubed tests and Windsor Probe
tests are generally quite comparable.
The Windsor Probe is much easier as
it is simply a matter of firing a bolt
with a predetermined charge into the
concrete and measure the depth of
penetration. It is somewhat destructive
in that there’s a small hole left
with a bolt sticking out of it. Cubed
tests are totally nondestructive unless
they are taken as cores. The major
problem with cubed tests is always
the question -- was the concrete cured
under exactly the same conditions that
are in the facility itself.
Concrete Thickness
Every endeavor is made to make
concrete the proper thickness. This
thickness is gauged by the amount of
embedment on the steel and by the
experience of the nozzleman. It is
further checked and corroborated by
the calculations of the volumes needed
for the project. In general, however,
the thickness is less important than
properly embedding all of the reinforcing
steel.
When 1/2 inch to 3/4 inch of concrete
covers the rebar on both sides, it
is thick enough.
The MudSlinger GHP1500 concrete pump is
an ideal size for building fences. This is a
very simple pump and can be driven by running
an air compressor.
Safe Operations and Practices
The use of appropriate safety equipment
is required. This includes face shields, or
safety goggles, respiratory protection (as
needed) and waterproof gloves. Wet concrete
will “burn” unprotected skin. Shoes
should be water proof and provide physical
protection to the wearer. The first layer of
shotcrete should be about 1/2 to 3/4 of one
inch. After it is set, a second coat can be
applied to bury the rebar.
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