Possible actions for pavement distresses occur on the proposed group project road:
Alligator cracking
1. Full depth shot repairs
This can be done by replacing the deteriorated asphalt surfacing with suitable bituminous mix placed
and compacted to the similar level to adjacent undeteriorated asphalt. The two types of bituminous
patching materials that can be used are hot mix asphalt and cold mix asphalt.
The construction process should be:
a)
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Marking
The boundaries identified to be patched should be marked
Preferred the straight line marking
These boundaries can be changed during cutting for undetected damage
b) Cleaning and drying
 The surface under the new patch must be clean, dry and free from loose material
 Air blowing followed by vacuum cleaning is recommended for efficient cleaning and drying
c) Tack coating
 A thin of bituminous is normally sprayed uniformly on the prepared surface prior to
patching hot mix to promote adhesion between the new layer and the cut surface.
 Tack coat materials should be cutback asphalt, emulsified asphalt or synthetic resin to be
used as the material for patching.
Bleeding
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Minor bleeding can often be corrected by applying coarse sand to blot up the excess asphalt
binder.
Major bleeding can be corrected by cutting off excess asphalt with a motor grader or
removing it with a heater planer.
Chip sealing with less binder
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A single chip seal is an application of binder followed by an aggregate. This is used as a
pavement preservation treatment and provides a new skid resistant wearing surface, arrests
ravelling, and seals minor cracks.
For a major bleeding, double chip sealing is used. It is application of two single seal coats.
The second coat is placed immediately after the first. This treatment waterproofs the
surface such as seals small cracks, reduces oxidation of the pavement surface, and improves
friction.
Block cracking
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Use slurry seal type II (general) as this type is coarser than a Type I aggregate slurry (it has a
maximum aggregate size of 6.4 mm (0.25 inches)) and is used to treat existing pavement
that exhibits moderate to severe raveling due to aging or to improve skid resistance.
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For low severity cracks (< 12.7 mm wide), Crack sealing to prevent the entry of moisture into
the sub grade through the cracks and also to further raveling of the crack edges.
Potholes
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Patching
Full-depth patches are necessary if the entire depth of pavement is distressed. Often times,
the underlying base, subbase or subgrade material is the distresses root cause and will also
need repair.
Partial depth patches are used for pavement distresses like raveling, rutting, delamination
and cracking where the depth of crack does not extend through the entire pavement depth.
Longitudinal crack
Cutting and patching involves the replacement of deteriorated asphalt surfacing with suitable
bituminous mix placed and compacted to similar level to adjacent undeteriorated asphalt. Two types
of bituminous patching materials commonly used are hot mix asphalt and cold mix asphalt.
To cut and patch helps to remove existing cracks and thereby eliminate reflection cracks. Cracks on
the deteriorated pavement need to be totally removed to prevent reflection cracks on the new
layer.
Edge drop-off
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Widening the pavement
Replace shoulder material and reconstruct
Levelling of shoulder with road surfaces
Shoulder material with inadequate resistance to erosion and abrasion.
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Insitu stabilise existing shoulder material with emulsion or replace material with good
quality material.
Resurfacing of pavement without resurfacing of shoulder.
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Tyne and add additional material and regrading and compact, preferably with an asphalt
edge beam at the same time.