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Idiomas disponibles
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Introduction
WARNING
product, you must read and understand the
safety chapter.
Basic working techniques
Contraction joints and joint spacing
As concrete hydrates or cures and begins to set, it
develops internal stresses which may cause random
cracks.
Random cracks cast doubt on the quality and
workmanship of the concrete. Contraction joints are cut
in concrete to relieve these stresses before they seek
their own relief in the form of random crack.
The Soff-Cut Ultra Early Entry system controls random
cracking through the early timing of a saw cut at
predetermined locations to create weakened planes in
the concrete that subsequently crack at the bottom of
the cut to relieve stress.
Sawed contraction joints must be a minimum of ⅛ of the
concrete depth and a minimum of 25 mm (1ʺ) deep.
Saw contraction joints when the concrete holds the
weight of the product and the operator. Make sure that
the product does not make marks on or cause damage
to the concrete.
There are many possibilities for joint layout. Joint layout
should be provided, the saw contractor should submit a
detailed joint layout for approval prior to cutting.
There are many conditions that have an effect on joint
spacing.
•
Concrete thickness.
•
Type, amount and location of reinforcement.
•
Shrinkage potential of concrete-cement (type,
quantity), aggregate (size, quantity, quality), water to
cement ratio, admixtures, concrete temperature.
•
Base friction.
•
Slab restraints.
•
Layout of foundations, racks, pits, equipment pad,
trenches, etc.
•
Environmental factors - temperature, wind, humidity.
•
Methods and quality of concrete curing.
Generally, contraction joint patterns should divide slabs
into approximate square panels per the recommended
spacing shown in the table.
Concrete thickness, mm
(in.)
90 (3.5)
794 - 001 - 19.04.2022
Operation
Before you operate the
Maximum spacing, m (ft.)
2.4 (8)
Concrete thickness, mm
(in.)
100, 114 (4, 4.5)
125, 140 (5, 5.5)
150 (6) or greater
At all intersecting cross cuts, install Husqvarna joint
protectors at each joint to prevent joint damage. Install
an additional joint protector where the right wheel will
cross the joint to prevent concrete damage.
Maximizing the Soff-Cut system
"The timing of concrete operations - especially finishing
and jointing - is critical... Failure to address this
issue can contribute to undesirable characteristics in
the wearing surface as cracking..." (Extract from the
foreword of the American Concrete Institute (ACI) 302.1
R-96.)
The Soff-Cut Ultra Early Entry system has revolutionized
the method used to control random cracking.
In order for an operator to do a satisfactory job using the
Soff-Cut system, the following criteria must be met:
•
A Soff-Cut Ultra Early Entry dry up-cut saw.
•
A Husqvarna Soff-Cut dry-cutting diamond blade.
•
A Husqvarna anti-ravel skid plate installed with every
new diamond blade.
•
An operator skilled in using the Soff-Cut Ultra Early
Entry cutting system.
Without this, joints can not be cut clearly enough to
control random cracking before it starts, which is what
the building owner is paying for.
The ACI Spec 302.1R-96 says it best:
"Early-entry dry-cut saws use diamond-impregnated
blades and a skid plate that helps prevent spalling.
Timely changing of skid plates is necessary to effectively
control spalling. It is best to change skid plates in
accordance with manufacturer's recommendations...The
goal of saw-cutting is to create a weakened plane
as soon as the joint can be cut...The timing of the
early-entry process allows joints to be in place prior
to development of significant tensile stress in the
concrete..."
The Portland Cement Association (PCA) engineering
bulletin, Concrete Floors on the ground, also states:
"Proper jointing can eliminate unsightly random cracks.
Aspects of joining that lead to a good job are choosing
the correct type of joint for each location, establishing
a good joint pattern and layout, and installing the
joint at the correct time... Timing of joint sawing is
critical...Lightweight, high-speed, early-cut saws have
Maximum spacing, m (ft.)
3.0 (10)
3.6 (12)
4.5 (15)
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