FAQ
Asphalt
Paving & patching Q&A
When
can we drive on our new driveway?
Why are
there scuff marks on new asphalt surfaces?
What
are some of the causes of asphalt failure?
What
causes fatigue cracks in pavement?
Why
doesn't asphalt stay that nice rich black colour?
What
causes potholes?
What
causes alligator cracks?
Why
are there cracks in the asphalt along the edges?
When
should a parking lot be patched?
How
thick should the asphalt be?
Remove & Replace Q&A
This is the process of completely removing the existing
pavement and replacing it. It is the most extreme rehabilitation
process there is.
When
must a pavement be removed and replaced?
Won't
all pavements have to be removed and replaced at some
point?
How
long does this R+R process take?
Should
a geo-technical engineer be involved with a remove and
replace project?
Resurfacing
Q&A
Resurfacing is the process of installing a new layer
of asphalt (generally one and a half to two inches)
over the existing pavement (also known as overlaying).
When
should a parking lot be resurfaced?
How
long should a newly resurfaced lot last?
How
long before traffic is permitted on a newly resurfaced
lot?
Sealcoating Q&A
Sealcoating is the process of applying an asphalt emulsion
over an asphalt pavement to prevent oxidation damage
and prolong the life of a new, structurally sound, asphalt
pavement.
Why
do I need to seal asphalt?
How
does sealcoating work?
When
should a parking lot be sealcoated for the first time?
How
long should the first sealcoat application last?
Will
sealcoat waterproof a cracked pavement?
Will
sealcoating allow us to get anther couple of years out
of our old, cracked pavement?
What
is a slurry seal?
What
is sealcoat?
Will
the sealcoating material track into my buildings?
How
do you block off sections in a parking lot?
Why
are there tire marks showing on a newly sealcoated parking
lot?
How
long before people can walk on the freshly sealed pavement?
Cracksealing Q&A
Cracksealing is the process of injecting a hot pour
rubberized sealant into isolated cracks in the asphalt
pavement to prevent water from penetrating the sub-grade
and stone base.
What
causes the cracks in my asphalt?
When
should cracks be sealed?
How
often should a lot be cracksealed?
Why
do you rout or cut the crack and make it bigger?
Why
can't alligatored areas be cracksealed?
How
long does it take the material to dry?
What
are the benefits of Petrotac?
Will
sealcoat material stick to cracksealing material?
Speedhumps
& Speedbumps Q&A
Speedhumps are large traffic calming devices usually
installed on streets to reduce speeding and cut through
traffic. Speedbumps are narrow traffic calming devices
used in parking lots to protect pedestrians.
What
is the standard size for a speedhump?
What
is the standard size for a speedbump?
Where
should speedbumps be installed?
Where
should speedhumps be installed?
FAQ Answers...
When can we drive on our
new driveway?
Usually in a day or two unless it is really hot. If
you can avoid turning the wheels of your vehicles when
it is not moving that will help prevent scuffing.
For asphalt resurfacing, depending upon the temperature
of the day, one should allow 2 to 6 hours before using
the new lot.
Sealcoating needs a 24-hour drying (curing) time after
work is completed. Do not allow traffic on your lot
before the end of the 24-hour drying period.
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Why are there scuff marks
on new asphalt surfaces?
Scuffing of newly sealed or paved surfaces
are inevitable as it is the nature of asphalt material
combined with hot weather. After about a month those
scuff marks are rarely noticeable. The scuffs are just
the sand being displaced and will wash away. Asphalt
requires about 6 months to fully cure. Until that time
it is tender and best to be a little careful. Avoid
tight turns, and turning the steering wheel when the
vehicle is not moving. Avoid sudden stops if you can.
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What are some of the causes
of asphalt failure?
Inadequate thickness of the pavement section to support
the loads that travel across the asphalt, lack of maintenance,
and weak or unstable subgrade components.
Asphalt
deteriorates when weather and traffic wear "fines"
aggregates away. When the "fines" are worn
away, there is nothing to bind the larger aggregates
together and the surface begins to ravel. This weakens
the pavement section and eventually allows water to
penetrate the subgrade, which leads to pavement failure.
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What causes fatigue cracks
in pavement?
Fatigue cracks are the direct result of excessive bending
of the pavement surface. Asphalt will fail if subjected
to repetitive or excessive bending as from vehicular
traffic.
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Why doesn't asphalt stay
that nice rich black colour?
The UV rays from the sun breakdown the carbon bonds
in the asphalt oil thus causing the colour to change
from black to gray. It is this oil that binds everything
in the asphalt together so when it is depleted erosion
starts, some sand particles at first and then larger
pebbles to stones then with water infiltration it is
all down hill from there. This oil is also what keeps
the asphalt flexible. So when the asphalt is gray and
oxidized it is less flexible and more prone to cracking.
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What causes potholes?
Possible causes of potholes include asphalt that was
too thin, base failure under heavy loads or poor drainage
that weakens the subgrade and base. Poor quality (segregation
in the asphalt, poor compaction, or asphalt that was
burnt or did not have enough oil mixed into it) may
be a contributing factor.
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What causes alligator
cracks?
Usually alligator cracking is caused by excessive deflection
of the pavement due to an unstable base or due to repeated
traffic loads heavier than what the road was built to
withstand. If this cracking is not addressed then it
will expand and cause more damage.
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Why are there
cracks in the asphalt along the edges?
Edge cracks are usually caused because there is not
enough support next to the road or the base has washed
out. It is good if you can avoid driving on the edge.
If you do get cracks have them filled with a rubberized
crack filler. If the cracking is severe then it may
have to be cut out and replaced.
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When should
a parking lot be patched?
patching is a repair operation and can be done as often
as needed, until a lot reaches the resurfacing stage
(over 35% of the lot is alligator cracked). Damaged
areas will get much worse over the winter so it is best
to get them done before then. Book the repair work early!
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How thick should
the asphalt be?
Asphalt pavements have defined strength co-efficients
that determine their service life based on actual traffic
conditions. The thicker the asphalt, the longer the
pavement will last. For patching we like to put at least
an inch more than what was originally installed.
In
general, we use the following guidelines to determine
asphalt depths:
-
2"
Car traffic only, no truck traffic ever
-
3"
for driveways that have the occasional delivery
or septic truck
-
4`5"
Light truck traffic, 1-5 large trucks per day
-
6`7"
Heavy truck traffic, 5-30 large trucks per day
-
8`10"
Very heavy truck use (ex: city street or runways)
If
there are budget constraints, do less area at the appropriate
depth, not more area at less depth!!
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When must a
pavement be removed and replaced?
If the existing pavement system is completely unusable
due to age, neglect or change of use, then there is
no other option but to remove and replace it. If the
asphalt lot or driveway is 60% cracked then it is more
cost effective to remove it all and start over, opposed
to continued patching.
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Won't all pavements
have to be removed and replaced at some point?
No. If a pavement is consistently maintained it will
never have to be completely replaced. With sufficient
planning, a complete rehabilitation project will restore
a pavement to as new condition or better.
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How long does
this R+R process take?
The entire pavement system must be removed with excavating
equipment and hauled to a landfill. New gravel is trucked
to the site, graded and compacted prior to paving. So
size of the job and distance from the gravel pit and
asphalt plant play a big part in the timing, but on
average it is less than a week for smaller lots and
two to three days for a large acreage driveway.
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Should a geo-technical
engineer be involved with a remove and replace project?
Since this is such a large expense, it is wise to seek
professional guidance on pavement design and specifications.
The existing pavement and sub-grade should be tested
and the projected traffic use calculated to determine
the best design.
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When should
a parking lot be resurfaced?
Resurfacing a lot is ideal when the surface has become
heavily oxidized but the base is still stable. Usually
when the asphalt is approximately 12 to 15 years old,
provided it was paved and maintained properly (correct
thickness for the traffic, proper compaction, correct
type of asphalt, proper drainage, etc.)
Resurfacing when the weather is dry and warm is essential.
Paving when it is cold leads to cold "seams"
and possibly less than ideal compaction, which can contribute
to premature failure. The general rule of thumb is to
pave when temperatures are 10° C and rising.
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How long should
a newly resurfaced lot last?
Depends on deflection of the original pavement (prior
to resurfacing), how many trucks use the pavement and
the thickness of the new asphalt layer, but generally
you can expect at least 8 to 12 years before more serious
maintenance is required.
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How long before
traffic is permitted on a newly resurfaced lot?
Rubber tire traffic will not damage the new asphalt
but care should be taken to avoid sharp turns (especially
power steering marks created by non-moving vehicles).
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Why do I need
to seal asphalt?
Asphalt is a very complex mixture of thousands of chemicals,
which are predominantly open chain (aliphatic) in structure
with a considerable degree of un-saturation within their
molecular structure. The open chain provides easy access
to water, salt, oils which disintegrates the asphalt
molecules, i.e. reducing its binding and waterproofing
abilities. The first sign of this is the change in the
asphalt's colour. It changes or fades from black to
gray.
Once the asphalt binder has been lost, the surface will
become brittle and start to ravel (top layer of rocks
will loosen and start to come out) the flexibility will
lessen and cracks will appear. Water will get into the
base and damage the pavement's load bearing capacity.
By sealcoating, we are providing a flexible, stable
and homogeneous compound to act as a barrier to protect
asphalt surfaces from the damaging effects of the elements.
How long should traffic stay off the parking lot after
you seal it?
Ideally we recommend that it be allowed to cure for
24 hours or at least over night.
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How does sealcoating
work?
It is like sun block. We know that asphalt is a mixture
of aggregate (small stones) and mineral fillers (sand)
combined with 4.5% to 12% (average 6%) asphaltic binder
(asphalt cement). It is this binder that needs to be
protected from deterioration. This binder is highly
subject to problems with ultraviolet rays, moisture
and traffic overload. By placing a sealcoat over the
asphalt you are placing a protective barrier over the
asphalt. This process of applying a sealcoat every 3-6
years will double the life of your asphalt, saving you
from having to carry out costly repairs.
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When should
a parking lot be sealcoated for the first time?
Short answer is one year from construction. Ideally
an asphalt pavement should be sealed as soon as the
surface has fully cured (6 months). Sealer can only
be applied when it is sunny and the temperature is 15°C
and rising.
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How long should
the first sealcoat application last?
This depends on many factors: the number of coats, the
amount of traffic, how much sand and salt is put on
in the winters, whether it is in the shade more than
the sun, how much water runs over it, etc. Having said
that, the average for driveways is between 4 and 6 years.
Parking lots and Condos 3 to 5 years but less at the
entrances.
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Will sealcoat
waterproof a cracked pavement?
Absolutely not! A sealcoat is a preservative coating
but has no structural value. Minor cracks should be
sealed with a hot pour, rubberized material prior to
sealcoating. Network cracked areas should be excavated
and repaired with a sufficient thickness of asphalt
prior to sealcoating.
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Will sealcoating
allow us to get anther couple of years out of our old,
cracked pavement?
Unfortunately no. This is a common misconception. Sealcoating
at the end of a pavement life cycle is a waste of money.
It would be like someone painting a car that had rusted
out. Cracks will only be highlighted and water will
continue to have a free path to the base layer. If a
driveway or parking lot is too far gone, it is better
to save the money spent on sealcoating and apply it
towards repairs and eventually an overlay of new asphalt.
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What is a slurry
seal?
It is similar to a sealcoat but has a significant amount
of graded aggregate mixed into the emulsified asphalt.
It is applied to the pavement by a squeegee and is generally
used to improve the quality of the pavement surface
rather than just to maintain its current state.
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What is sealcoat?
It is a general term for any of a variety of coal tar
or asphalt emulsions applied to a relatively sound asphalt
surface to prevent damage from ultraviolet rays, moisture
and oxidation.
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Will the sealcoating
material track into my buildings?
Each section must be secured prior to the start of work.
Schedules must be communicated to the tenants so that
everyone understands the traffic patterns throughout
the project. The material will track if it is walked
on or driven on before it has dried.
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How do you
block off sections in a parking lot?
Developing a plan to section off the parking lot to
maintain traffic flow through the project is critical
to its success. Tenants must be informed throughout
the process so they can plan accordingly. Each area
is blocked off with tape and barricades. Each parking
lot is different so the sectioning plan and barricading
plan must be customized to the needs of the tenants
and the property manager.
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Why are there
tire marks showing on a newly sealcoated parking lot?
The material drys to the touch in a few hours but it
takes several weeks to fully harden, especially in the
hot sun. Expect power steering marks as the sand is
sheared away from the sealer but over time these marks
will go away.
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How long before
people can walk on the freshly sealed pavement?
People can walk on freshly sealed pavement after 1 or 2 hours
depending on temperature and relative humidity.
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What
causes the cracks in my asphalt?
All pavement failure starts with a crack. Asphalt cracking
is caused primarily by the effects of sun and moisture
and ground movements. Asphalt is flexible when new,
but with age it becomes more rigid and is less able
to tolerate vertical deflections. This causes a tension
and pulling apart in the pavement and before you know
it you have a crack. Once the crack is open, moisture
is able to reach the pavement's subsurface and soften
it, or freeze and expand it. Soon the pavement begins
to deteriorate around the crack, creating a larger problem.
Proper attention to the cracks will prevent the problems
from spreading and double the life of the pavement.
Treating the problem while it is still small will pay
big dividends later by delaying costly resurfacing.
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When
should cracks be sealed?
The sooner the better. Any crack will allow moisture
to penetrate to the subsurface and the larger the cracks
the faster this happens. The goal of a good pavement
management plan should be to keep the moisture from
entering the asphalt pavement; however, only isolated
cracks should be sealed, never alligatored areas.
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How often
should a lot be cracksealed?
Since this is a maintenance operation, it can be done
as often as needed. Pavements on a yearly maintenance
and repair plan, should budget for this once a year.
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Why do
you rout or cut the crack and make it bigger?
This is similar to why a dentist drills a cavity to
make it bigger, so you can better fill it. The regular
cracksealing operation (which we do not recommend because
it is just a band aid solution to a problem that requires
stitches) involves trying to pour the sealant into isolated
cracks throughout the pavement. When routing is added
to this operation, all cracks are routed to a uniform
width before injecting the sealant. Routing provides
a uniform reservoir to hold the material, thus widening
the crack, which reduces the degree of expansion during
freeze thaw cycles.
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Why can't
alligatored areas be cracksealed?
When alligatored areas appear in a parking lot it means
that water has penetrated the sub-grade layer and the
pavement can no longer support the weight of the traffic.
Cracksealing is not the solution at this stage.
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How long
does it take the material to dry?
The cracksealing material is applied at 300° F but
cools to the touch in minutes and can be open to traffic
almost as fast without worry of it tracking.
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What
are the benefits of Petrotac?
Petromat serves as a waterproofing membrane between
the existing surface and the new surface. It adds about
one inch of proportionate asphalt strength to the overlay.
It also aids in slowing the migration of cracks from
the underlying surface to the new one. Ultimately, Petrotac
significantly extends the life expectancy of a new asphalt
surface.
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Will
sealcoat material stick to cracksealing material?
The two materials will bond but since the cracksealing
material is designed to flex through a wide temperature
range, the sealer will chip off from the crackseal.
Expect a color difference between the two materials.
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What
is the standard size for a speedhump?
Speedhumps are typically 22' long by the width of the
street. There are 6' ramps on either side of a 10' plateau
in the middle of the speedhump.
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What
is the standard size for a speedbump?
Speedbumps are typically 3-4' wide and rise to a height
of 3". Speedbumps should be at least 3' wide and
be formed with a gradual radius to prevent damage to
vehicles.
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Where
should speedbumps be installed?
Generally, speedbumps are installed in a parking lot
to slow drivers down and protect pedestrians. If possible,
install speedbumps between islands so that cars cannot
drive around them.
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Where
should speedhumps be installed?
Speedhumps are usually installed on streets. Condos
or cities request them to reduce speeding and cut through
traffic on neighborhood streets.
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