Concrete
The length of curing time after concrete is poured greatly
affects the way a diamond blade will interact with it during
cutting. Curing can be affected by weather (temperature, moisture
and time of year) and the composition (admixtures, aggregate and
sand). Cured concrete is typically set at least 48 hours. The sand
is completely bonded with the mortar and the concrete reaches full
hardness.
Green Concrete
Concrete is typically in its green state for 6 to 48 hours after
it is poured. In this early state, the sand is not completely
bonded with the mortar and the concrete doesn't reach full
hardness. When cutting green concrete, the sand loosens more
readily, and flows more freely in the slurry, and produces much
more abrasion on a diamond blade.
Undercut protection is critical when cutting green concrete to
prevent excessive wear on the steel core at the segment weld. Green
concrete sawing is common when working on new construction projects
such as; motorways, runways, driveways & industrial
flooring.
Aggregates
Aggregates are the granular fillers in cement that can occupy as
much as 60% to 75% of the total volume. They influence the way all
diamond tools perform. Aggregates can be naturally occurring
minerals, sand and gravel, crushed stone or manufactured sand. The
most desirable aggregates used in concrete are triangular or square
in shape; with hard, dense, well-graded and durable properties. The
average size and composition of aggregates greatly influence the
cutting characteristic of a diamond blade.
Large aggregates tend to cause blades to cut slower, and smaller
aggregates allow the blades to cut faster.
Aggregate hardness is a very important factor when cutting
concrete. As hard aggregate, Such as flint, dulls diamond grit more
quickly, segment bonds generally need to be softer when cutting
hard aggregate. This allows the segment to wear normally and bring
new sharp diamond grit to the surface. Softer aggregate will not
fracture diamond grit as quickly, so harder segment bonds are
needed to hold the diamond in place long enough to use their full
potential.
Steel reinforcement
Further strengthening and structural integrity of concrete is
accomplished by introducing concrete reinforcing steel bars
(Rebar), Steel Wire Strand or Wire meshing into the concrete. It
costs more to cut concrete that contains reinforcing steel because
cutting rates are slower and blade life is reduced. If the cross-
sectional area of concrete is 1-% steel, the blade life will be
about 25% shorter than if no steel were present. Concrete with 3%
can reduce blade life as much as 75%.
Asphalt
Hot Mix Asphalt (HMA) is a mixture of Asphalt Concrete (a
petroleum based "glue" that comprises less than 8% of weight of the
total pavement mixture) and aggregates of various sizes and sand.
Asphalt does not cure as concrete does, and once spread and rolled,
it can be cut or drilled almost immediately. Unlike cured concrete,
sand in asphalt never bonds as firmly, and the slurry created when
sawing will be extremely abrasive.
A metal bond similar to cutting green concrete and undercut
protection for the steel core are important factors when
undertaking asphalt-cutting operations.
It is common for many operators to cut through the asphalt layer
into the sub-base. However, this should be discouraged as generally
the sub-base contains high contents of very abrasive materials such
as sand and dirt. This undesirable situation causes rapid wear of
the diamond blade.
Brick and block
Generally concrete building block tends to consistently have
soft, abrasive qualities while brick tends to be harder and less
abrasive. There are a large variety of brick types on the market,
each designed and manufactured to provide certain qualities. The
degree or hardness is mostly determined by the clay mixture, method
of manufacture and the firing temperature.
Stone
Natural stone comes in a variety of hardness, so it is important
to take care in selecting the appropriate diamond blade. If in
doubt ask us to specify the right blade for you.
| « Hard |
Soft » |
| Flint |
Granite |
Slate |
Marble |
Flagstone |
Sandstone |
Limestone |
Ceramic Tile
Ceramic tile is typically on the higher range of the hardness
scale although there are some differences between each type based
on clay mixture, manufacturing processes and firing temperature. A
common concern when cutting tile is chipping. For this reason,
diamond blades with continuous rims, closely spaced segments or
turbo segments are often popular choices.