Marshalltown SG87SH SURFACE SHARK Floor Grinder - Manual (Page 26)

PAGE 26 SG87Sh SuRFACE ShARK FLooR GRINDER
STOPPING THE SURFACE GRINDER
Application: SG87SH SURFACE SHARK
The SG87Sh Floor Grinder is stopped by rotating or
releasing the starter control grip with the right hand to
the oFF position. When not in use, turn the oN/oFF
master switch to the oFF position.
OPERATIONAL PARAMETERS AND TECHNIQUES
FOR THE FLOOR GRINDER
Application: SG87SH SURFACE SHARK
Early Age Grinding
Early age grinding is an alternative to floating and
troweling. It gets it name from the fact that the concrete
is ground at an early age, after it has set but before
it has gained much structural strength. The process
usually involves the following steps:
1) Normal screeding of the floor.
2) Smoothing the floor surface with a skip float.
3) Cover the floor with polyethane sheeting.
4) Removing the sheeting and grinding the floor down
a uniform depth of approximately 1/32 inch within 24 to
48 hours of the initial pouring. The C10 silicon carbide
grinding stones are usually used for the process,
although the multi segmented, dry diamond blades
can be use as an alternative with substantially greater
productivity rates. The main benefit of early age
grinding is that it eliminates late work in cold weather.
With ordinary finishing methods, a slab cast in the
morning of a cold weather day might not get finished
troweled until very late at night. With grinding, the
construction crew is able to leave the job at the end
of a normal work day and return 1 or 2 days later to
finish the job. Early age grinding may not reduce the
total number of work hours, but it usually eliminates the
need for work at overtime rates, which can substantially
increase total project costs.
one side benefit of early age grinding is that the
process demands less skill than conventional floating
and troweling. This makes it an attractive process
where skilled crew personnel may not be available.
It is also an excellent procedure for concrete floors
that will be eventually covered by carpet or an applied
coating.
Definitions of Floor Flatness and Levelness.
The terms flatness and levelness have poorly
understood meanings in everyday speech, but have
important distinctions in floor construction.
Flatness is defined as planarity or lack of curvature. A
more simple definition is that a flat floor is smooth and
free of bumps and dips. An unflat floor is bumpy and
wavy. Levelness is defined as horizontality or lack of
slope. A level floor is horizontal. A floor that is unlevel
is sloped or tilted.
A floor can be flat, but still not level. Some floors
are specifically designed to be unlevel; they can be
intentionally sloped for drainage considerations. very
few, if any, floors are specifically designed to be
unflat. unfortunately, many turn out that way. Flatness
and levelness are both desirable, but have different
implications for the floor user. Flatness is critical where
the user’s main concern is the behavior of wheeled
type vehicles. Levelness is critical where the user’s
main concern is with fixed structures such as shelving,
racks and the placement of machine tools.
Exceptions exist, but for most users, flatness is more
important than levelness. The reasoning is that fixed
equipment can be shimmed or adjusted to compensate.
however, it is not as easy to adapt a wheeled vehicle
to a floor that is not flat enough to allow for proper
action.
Flatness and levelness also have different implications
for the floor contractor. Flatness is determined mainly
by finishing methods. Levelness is determined mainly
by the side forms.
Defined Versus Random Traffic Patterns.
Floors are subject to two kinds of traffic patterns:
defined and random. on a defined traffic floor, vehicle
movement is confined to fixed paths. on a random
traffic floor, vehicles are free to roam, though inevitably,
some traffic patterns are used more than others.
The distinction is important because the two kinds of
traffic demand different methods of measuring surface
regularity. on a defined traffic floor, a continuous (or
nearly continuous) profile in each of the paths can be
measured. but where traffic is random, the possible
travel paths are infinite in number. What usually results
is statistical sampling; selected points or lines are
checked and assumed that they represent the whole
floor surface.