cracks. The minimum width of the prepared crack
should be 6 mm1/4 inch.
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3.8.1.1
Preparation
Clean cracks by saw cutting or routing to provide the proper profile for
sealants. After the crack is sawcut or routed, clean the surfaces by
sandblasting and/or waterjetting. Adjust the height, angle of inclination
and the size of the nozzle as necessary to provide satisfactory results.
Provide protective covers and barriers as required to prevent over-spray
onto adjacent surfaces. Remove dust, dirt and loosely bonded materials
resulting from cleaning. Ensure surfaces are dry before application of
repair material. Apply bond breaker to the bottom of the routed or sawed
crack. Where cracks extend through surfaces to be repaired, make the
repair first and then tool, rout or saw the original line of the cracks
into the repaired area.
3.8.1.2
Rate of Progress
Limit the stages of crack sealing, which includes preparation and placement
of bond breaker, so only that length of crack that can be sealed during the
same workday is prepared.
3.8.1.3
Time of Application
Seal prepared cracks immediately following the cleaning and drying process.
Walls of the prepared crack shall be surface dry, and the atmospheric and
concrete temperatures shall be above 10 degrees C (50 degrees F)50 degrees F
at the time of application of the sealant. Provide an approved temporary
seal for open routed cracks that cannot be sealed under the conditions
specified.
3.8.1.4
Sealing
Do not apply sealant until the prepared cracks have been inspected and
approved. [Place masking tape on the finish surface on one or both sides
of a crack cavity to protect adjacent finish surfaces from primer or
sealant smears. Remove masking tape within 10 minutes after crack has been
filled and tooled.] Fill the cracks from the bottom up and tool the top
surface as indicated or as recommended by the manufacturer. Apply sealant
in accordance with ACI 504R.
3.8.1.5
Preformed Compression Seals
Rout or cut the crack to the dimensions indicated. Install the seals with
equipment that is capable of installing joint seals to the prescribed depth
without cutting, nicking, twisting, or otherwise distorting or damaging the
seal and with no more than five percent stretching of the seal. Cover the
sides of the crack and, if necessary, the sides of the compression seal
with a coating of lubricant, and install the seal to the depth indicated
with joint installation equipment. Coat butt joints with liberal
applications of lubricant.
3.8.2
Filling Cracks with Grout or Mortar
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NOTE: Filling cracks is not effective for active
cracks. The prepared crack should be minimum 25 mm
SECTION 03931
Page 60
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