type of construction joint shall be subject to approval of the Contracting
Officer. Unless otherwise indicated and except for slabs on grade,
reinforcing steel shall extend through construction joints. Construction
joints in slabs on grade shall be keyed or doweled as shown. Concrete
columns, walls, or piers shall be in place at least 2 hours, or until the
concrete begins to lose its plasticity, before placing concrete for beams,
girders, or slabs thereon. In walls having door or window openings, lifts
shall terminate at the top and bottom of the opening. Other lifts shall
terminate at such levels as to conform to structural requirements or
architectural details. Where horizontal construction joints in walls or
columns are required, a strip of 25 mm 1 inch square-edge lumber, bevelled
and oiled to facilitate removal, shall be tacked to the inside of the forms
at the construction joint. Concrete shall be placed to a point 25 mm 1 inch
above the underside of the strip. The strip shall be removed 1 hour after
the concrete has been placed, and any irregularities in the joint line
shall be leveled off with a wood float, and all laitance shall be removed.
Prior to placing additional concrete, horizontal construction joints shall
be prepared as specified in paragraph Previously Placed Concrete.
3.9.2
Contraction Joints in Slabs on Grade
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NOTE: Drawings must indicate desired location and
detail for contraction joints.
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Contraction joints shall be located and detailed as shown on the drawings.
Contraction Joints shall be produced by forming a weakened plane in the
concrete slab by [use of rigid inserts impressed in the concrete during
placing operations] [use of snap-out plastic joint forming inserts] [or]
[sawing a continuous slot with a concrete saw]. Regardless of method used
to produce the weakened plane, it shall be 1/4 the depth of the slab
thickness and between 3 and 5 mm 1/8 and 3/16 inch wide. For saw-cut
joints, cutting shall be timed properly with the set of the concrete.
Cutting shall be started as soon as the concrete has hardened sufficiently
to prevent ravelling of the edges of the saw cut. Cutting shall be
completed before shrinkage stresses become sufficient to produce cracking.
Reservoir for joint sealant shall be formed as previously specified.
3.9.3
Expansion Joints
Installation of expansion joints and sealing of these joints shall conform
to the requirements of Section 03150A EXPANSION JOINTS, CONTRACTION JOINTS,
AND WATERSTOPS and Section 07920 JOINT SEALANTS.
3.9.4
Waterstops
Waterstops shall be installed in conformance with the locations and details
shown on the drawings using materials and procedures specified in Section
03150A EXPANSION JOINTS, CONTRACTION JOINTS, AND WATERSTOPS.
3.9.5
Dowels and Tie Bars
Dowels and tie bars shall be installed at the locations shown on the
drawings and to the details shown, using materials and procedures specified
in Section 03200A CONCRETE REINFORCEMENT and herein. Conventional smooth
"paving" dowels shall be installed in slabs using approved methods to hold
the dowel in place during concreting within a maximum alignment tolerance
of 1 mm in 100 mm 1/8 inch in 12 inches. "Structural" type deformed bar
SECTION 03300A
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