3.8.3.2
Applying Sealer
Apply high molecular weight methacrylate sealer to prepared surfaces in
accordance with manufacturer's directions. Remove excess sealer, leaving
no visible surface film. Fill cracks greater than 3 mm (1/8 inch)1/8 inch
wide in accordance with sealer manufacturer's recommendations. Apply a
second treatment of sealer evenly over the cracks and remove excess sealer
on the surface. Cover with light broadcast of a dry masonry sand.
Distribute evenly over the surface at the rate recommended by the sealer
manufacturer. After a curing period of 12 hours at 23 degrees C (73
degrees F)73 degrees F, remove any loose sand by lightly brooming.
3.8.4
Drilling and Plugging Cracks
**************************************************************************
NOTE: Drilling and plugging is applicable only for
cracks which are reasonably straight and accessible
from one end. The hole must be large enough to
intercept the crack for its entire length. If load
transfer is necessary, plug the hole with grout. If
watertightness is necessary, but not load transfer,
plug the hole with resilient material.
**************************************************************************
Drill a [50] [75] mm ([2] [3] inch)[2] [3] inch diameter hole centered on
the crack. Clean the hole by flushing with water and compressed air prior
to placing grout. Fill the hole with [portland cement grout consisting of
one part portland cement, three parts fine aggregate, and sufficient water
to permit placement in the hole][bituminous joint sealant]. Place the
grout in lifts to avoid pressure from the weight of the grout causing the
grout to leak through the crack at lower levels.
3.8.5
Injection Grouting Cracks
**************************************************************************
NOTE: Portland cement grout is normally used to
seal wide cracks, but may be used to seal cracks as
narrow as 0.05 mm0.002 inch. Ultra-fine cement
grout may be used to seal cracks of a smaller size.
Epoxy resin is normally used for cracks between 0.13
and 6.3 mm0.005 and 0.25 inch wide. Polyurethane is
normally used for cracks greater than 0.13 mm0.005
inch wide.
The interval between valves should be greater than
the thickness of the member being repaired.
**************************************************************************
3.8.5.1
Preparation
Clean each crack of dust, dirt, loose concrete and unsound material by
vacuuming or flushing with water and allowing to dry to remove free water
in the crack. Insert a valve at both ends of each crack, at the junction
of two cracks, and along the length of each crack at [400 to 500][ ] mm
([16 to 20] [_____] inch) [16 to 20] [_____] inch intervals. Fill crack
between valves with crack surface sealer.
SECTION 03931
Page 62
Previous Page
