joints to remove all laitance, loose or deteriorated filler, and old
sealant from the sides and upper edges of the joint space to be sealed.
Clean joints to sufficient depth to remove all loose material and debris
and to permit placement of the backup material and sealant as shown on the
drawings. Concrete surfaces shall be dry at the time of sealant
application.
3.9.1.1
Existing Sealant Removal
Cut the in-place sealant and expansion joint material loose from both joint
faces and to the minimum depth required to permit placement of the back-up
material and sealant depth equal to one half the width of joint or as
recommended by the sealant manufacturer, unless otherwise shown on the
drawings, using the waterjetting equipment as specified in paragraph
EQUIPMENT. Removal may be efficiently accomplished using high pressure
water jet with abrasive added. Prior to further cleaning operations,
remove all loose old sealant remaining in the joint opening by blowing with
compressed air. Chipping, spalling, or otherwise damaging the concrete
will not be permitted.[ For compression seals, sawcut the joint to the
width and depth shown on the drawings.]
3.9.1.2
Sandblasting and Waterjetting
Sandblast or waterjet clean the newly exposed concrete joint faces to at
least the depth of the back-up material and sealant and the concrete
surfaces extending a minimum of 13 mm (1/2 inch)1/2 inch from the joint
edges. Use a multiple-pass technique until the surfaces are free of dust,
dirt, filler, old sealant residue, or any foreign debris that might prevent
the bonding of the sealant to the concrete. After final cleaning and
immediately prior to sealing, blow the joints out with compressed air to
ensure that the joints are completely free of debris and water.
3.9.1.3
Rate of Progress of Joint Preparation
Limit the joint preparation which includes sandblasting or waterjetting,
air pressure cleaning and placing of the back-up material to only that
lineal footage that can be sealed during the same day.
3.9.2
Installation of Sealant
Store and apply the primer and sealant in accordance with the
manufacturer's written safety instructions and precautions and using
manufacturer recommended procedures.
3.9.2.1
Time of Application
Seal joints immediately
following final cleaning of the joint sidewalls and
following the placement
of the bond breaker and back-up material. Reclean
open joints that cannot
be sealed under the conditions specified, or when
rain interrupts sealing
operations, and allowed to dry prior to installing
the sealant.
3.9.2.2
Back-Up Material and Bond Breaker
Plug or seal off the lower portion of the joint opening using a back-up
material to prevent the entrance of the sealant below the specified depth.
Take care to ensure that the backup material is placed at the specified
depth and is not stretched or twisted during installation.
SECTION 03931
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