Transcript Crack Treatment

Crack Treatment
Sponsored by:
Minnesota LTAP Center
Presented by:
Michael Marti, P.E.
SRF Consulting Group, Inc.
Dan Wegman, P.E.
SemMaterials
Filling vs Sealing
• Sealing involves prepping (creating reservoir,
cleaning, etc) where filling, at most, includes
blowing the crack clean.
• Crack filling is most often reserved for more
worn pavements with wider, more random
cracking.
• Crack sealing is normally done on cracks
which are less than ¾-inch wide, are spaced
uniformly and have limited edge deterioration.
Methods of Crack Treatments
• Crack Filling
– Preparation is fairly minimal, generally consisting
of blowing loose debris from the crack with
compressed air.
– In some cases, you can uses a hot air lance to clean
and dry the crack before applying the filler material.
– Mn/DOT Specification 3719, Crumb Rubber,
is recommended.
– The use of AC-3 as a crack filler is discouraged.
Methods of Crack Treatments
• Clean and Seal (formerly “blow and go)
– Make sure that cracks are clean and dry before
placing sealant
– Perform in late fall or early spring when cracks
are open
– Take care not to burn pavement with hot air lance
– Follow manufacturer’s recommendations for
sealant application
Methods of Crack Treatments
• Rout and Seal
– Over band should be about 2-1/2 inch
(¾” route plus ¾“ over band.
– Over band thickness should be as thin
as possible.
Methods of Crack Treatments
• Full-depth crack repair
– Milling depth varies from 1 ¼” for cracks in good
condition, to full depth for pavements with severe
deterioration in the crack vicinity.
– Mill width varies from 10 to 12” for shallow milling,
to 3 to 4” for deep milling.
– When choosing the configuration of the area to be
milled, the trench should be wide enough to
ensure good compaction. It is difficult to achieve
good compaction in a deep narrow trench.
Methods of Crack Treatments
• Crack Sealing and Overlays
– Crack sealing is recommended 6 to 12 months
prior to an overlay.
– To eliminate bumps caused by too much or
reactive sealant.
Methods of Crack Treatments
• Saw and Seal
– Place the sealant flush to the pavement surface.
– The strike-off will create a “slight over band” that
provides better adhesion of the sealant to the
pavement surface/reservoir edge corner.
Recommended Applications
Material
Lowmodulus
rubberized
asphalt
Mn/DOT Recommended Application
Spec
3720
3725
Initially recommended for rout and
seal method, using a ¾” x ¾”
reservoir and less over band.
Now 3725, which has slightly
higher resiliency properties, is the
recommended sealant for rout and
seal. It is also the recommended
sealant for saw and seal.
Recommended Applications
Material
Rubberized
asphalt
Mn/DOT Recommended Application
Spec
3723
• Was the common sealer for rout
and seal until recently (Now 3725)
• Good adhesion qualities
• Used for rout and seal in
situations where wider reservoir
widths are needed
• This product can also be used for
the clean and seal method
Recommended Applications
Material
Crumb
Rubber
Mn/DOT
Spec
3719
Recommended Application
• Very effective for clean and seal
method
• Works best in the early spring or
late fall when the cracks are open
• Although will crack in the winter, it
will re-heal during warmer
weather
• A double jacket melter is needed
to maintain proper temperature of
the product during application
Recommended Applications
Material
Asphalt
Emulsion
Mn/DOT
Spec
Recommended Application
CSS-1 • Used as a crack filler
CSS-1H • Emulsions are 33% water; will
CRS-2P
shrink with curing
HFMS-2 • Limited to use in warmer seasons
Recommended Applications
Material
Asphalt
Cement
Mn/DOT Recommended Application
Spec
AC-3
• Air blown asphalt used as crack
filler
• Will get quite brittle in the winter
• Will track in warmer weather
• Discouraged by Mn/DOT
Recommended Applications
Material
Cutback
Asphalt
Mn/DOT Recommended Application
Spec
RC
MC
SC
• Crack filler
• Not as readily available
• Not as safe as emulsions, but can
be used in the winter months