should I perform preventive maintenance?
How do pavements differ in cost and quality?
do the pot holes pop up year after year?
Pot holes always bust my budget. How can I prevent them?
the difference between resurfacing and resealing?
Where is the best Green Chili in Denver?
Who should I call for a good product at a fair price?
the invention of the wheel, man has cursed the mud and devised ways
to defeat it. Materials have evolved from Roman stone roads, to
cobblestone streets, to concrete and asphalt pavements. Pavements
act as a roof over the road base. If water gets under this roof,
it loses its support and will fail. With asphalt, this is the beginning
of the dreaded Pothole.
pavement is basically a mixture of rock and sand held together
by Portland cement. When water is added a chemical reaction takes
place. The mud must be placed and finished before the reaction
is too far along or it will lose its strength.
the chemical reaction heat is produced, the water evaporates,
and a rigid (rock-like) pavement results. For some applications
wire mesh, rebar or fiber mesh are included in the pavement
for additional strength. Concrete does not bend. It is strong
but brittle. It is especially useful for water courses (drain
pans, curb and gutter) and high weight loading areas (dumpster
pads). It is more expensive to install than asphalt but is a
wise investment for certain locations.
Asphalt pavement is a mixture of rock and sand held together
by liquid asphalt cement. Liquid asphalt is a product of crude
oil refining. It is heated and combined with the aggregate at
a temperature of over 300 degrees. It is placed and compacted
while hot and, when cooled, a flexible (spring-like) pavement
results. Asphalt will bend with traffic loads and with expansive
soils. If these factors are greater than the pavement is designed
to withstand, it may crack or break instead of returning to its
original shape. This kind of damage is commonly seen at dumpster
loading areas and in parking stalls.
in concrete can happen during the curing process. As the water
evaporates the concrete may shrink. For that reason, control joints
are placed at intervals to provide uniform weak points for the
pavement to crack. After curing, overloading or a poor base under
the pavement may also cause it to crack and break.
in asphalt generally occurs as it ages. Exposure to the sun
evaporates the light volatiles from the liquid asphalt that
binds the aggregate together. This causes shrinking and eventually
the asphalt pulls apart at a weak point. Control joints are
not used in asphalt to guide this cracking as they are in concrete.
loads are another cause of cracking in asphalt. They can compress
the asphalt beyond its design, breaking the bond, and leaving
DAMAGE TO ASPHALT PAVEMENTS
ultimate goal in asphalt pavement maintenance is to protect the
surface from the elements and to prevent water from infiltrating
through cracks into the base.
everything that contacts asphalt is bad for it.
can cause compression damage from overloading
tires can, especially on turns, scrub away the finer aggregates
from the pavement surface leaving a rough texture and a weaker
and fuel spills, which are petroleum products like the asphalt
cement, can soak into and soften the pavements so the aggregate
isn't bound together as good as it was originally.
can cause damage several ways. As it runs across the pavement
from sprinklers, (a daily occurrence 6 to 8 months a year), rain
and snow melt it washes away the fines from the top of the pavement
creating a rougher surface
penetrating the pavement through cracks can cause damage in both
warm and cold weather. In warm weather it soaks down into and
softens the base under the pavement. Since asphalt is flexible,
vehicle traffic will cause it to move up and down over the soft
base and pump out the base. This creates a void under the pavement
and allows it to fail under the weight of the vehicles on top.
cold weather you have the same expansion and contraction scenario
plus the freeze - thaw action that can create the void under the
pavement without the need for vehicles on top.
lots represent a sizeable investment. The best and most cost efficient
way to maintain this investment is to conduct various asphalt maintenance
procedures on the lots periodically.
are three main options for repairing asphalt pavements.
least expensive is a surface patch where the area is cleaned,
any loose debris is removed and a tack coat is applied. Hot-mix
asphalt is placed in the hole and compacted and another layer
is placed over the hole and surrounding area to seal it. There
is no cutting involved, very little material to haul away and
a relatively small amount of new asphalt needed.
process is best used where no cracks are evident such as an
area where water and traffic have worn away the pavement and
it is not broken or sunken. Another area would be where part
of an overlay has popped off and can be patched in.
areas where the pavement is sunken, heaved up, or cracked into
an "alligatored" pattern it is necessary to remove and replace
the existing asphalt from the base up. The damaged asphalt is
cut out and hauled away, the base material is graded and compacted
and new hot-mix asphalt is placed in at least two layers and each
layer is compacted. A surface patch doesn't work here because
the cracks extend through the pavement to the base and will reappear
unless a full depth repair is performed.
asphalt has reached a point where it has lots of patches, cracks
and otherwise is showing its age, an overlay may be called for.
The existing pavement is repaired to a point where it will provide
a solid base for the overlay, and then two inches of hot-mix asphalt
are placed and compacted.
some instances a paving fabric is incorporated with the overlay
to separate the new asphalt from the old, cracked asphalt.
PURCHASING PARKING LOT SERVICES
order to get a proposal that fits the needs of the pavement it is
best to know the condition of the parking lot. The best way to do
this is to periodically walk the lot and make notes or indicate
on a site plan areas of concern. Having accurate site plans and
notations of major concerns available for the contractor is a good
starting point and will improve the usefulness of the subsequent
overseeing asphalt repair is a new experience (or if you are on
a new property), it may help to look over old proposals to familiarize
yourself with the history of the property and the terminology used.
They may also be a source of questions on terminology and processes
that can be cleared up when meeting with the estimator.
an idea of the extent of the maintenance or repairs that the budget
will allow to be included in the bid.
Is the main concern potholes?
curb appeal a concern?
the lot in need of an extensive overhaul?
Try to set aside time to walk the lot with the contractor. This
allows both parties to note concerns and questions about specific
areas to be included in the proposal.
maintenance and repair is a positive for your pavement, for your
property, and can be for you, too.
Asphalt is here to answer questions, explain our services, give
informed advice, and provide quality service.
in one persons opinion, Santiago's
green chile is a killer (and I mean that in a good way)!