Importance of Crack Sealing

What type of maintenance is the best value?

As property managers or home owners, you certainly have to manage your time and money or that of your clients’. To this end, we offer you the simple question: which of the most common pavement maintenance options is the best value? Sure, every step is important from periodic sealing of the asphalt all the way up to pothole repair or asphalt replacement. But what activity can you do to the get the biggest bang for the smallest buck?

The answer of Hot Crack Sealing may surprise you, but the evidence is overwhelming. When done correctly the process of hot crack sealing includes cleaning the surface and channel of the crack, sealing the crack with molten tar, and then spreading a thin layer of aggregate to reduce immediate failure. Let me explain further.

Why Cracks Develop

Cracks develop in your asphalt – residential or commercial are both the same – when the different patches that make up your asphalt move in different directions and/or at different rates. Similar to how earthquakes are made by the shifting of the earth’s tectonic plates, your asphalt and the material underneath is always shifting and expanding or contracting. The case can be made in fact that your parking lot or driveway expands or contracts in any given day more than any other part of your property. Direct sunlight heats the surface which starts to expand while the earth keeps the lower parts of your asphalt consistently cool. This causes the different depths of your asphalt to expand or contract at different rates which causes the material to break down. Also, most parking lots or driveways are not shaded which only increases the exposure to the damaging elements. Underneath the driveway there are multiple processes at work from the shift of materials to the ever-dreaded water intrusion, even insect and wildlife – all of which can damage the substrate on which your asphalt is supported.  Isn’t asphalt amazing to be able to withstand all these factors!

Now that you understand why cracks develop, what can be done about them? And this brings us back to the question of the day: which procedure is the best value in pavement maintenance? And I will answer again: Hot Crack Sealing. The process of hot crack sealing is basically pouring hot tar (approximately 350 degrees fahrenheit) into the cracks to eliminate or reduce the amount of water that penetrates the surface.

How to correctly seal the cracks in your asphalt.

Crack Sealing with a Pump UnitWhile part of the crew is cleaning the cracks, we also begin heating the tar. There are special kettles that transfer the direct heat of the propane to the crack melt (crack melt is an industry term for the special tar used to seal cracks). Once the cracks are clean and the crack melt has reached it’s temperature, we can begin applying the crack melt to the cracks. This is done with a specialized walk-behind kettle or a pressurized hose. But the process doesn’t stop there.

Once the crack melt has been applied to the cracks, it remains exceptionally sticky until it cools. In general, the longer a substance takes to cure, the more durable the adhesive will remain.  Down in the channel of the crack, this “sticky-ness” is a great thing, but it can cause a problem on the top surface. This means that when an object (such as a car tire or a person’s shoe) rolls or walks over the top of the hot crack melt, the extreme adhesion of the crack melt can stick to the foreign substance and then pull out of the crack.  To insure proper curing of the crack melt, it is important to introduce a fine layer of aggregate to the top of the surface.  This creates a thin barrier to reduce the likelihood of the crack melt being pulled from the crack, allowing the tar to cure in place, which in turn creates the barrier to keep weather and other damaging elements out of your asphalt.  You probably had no idea that crack melt was so important!

We at Exterior Maintenance Service are happy to educate our customers on the various pavement maintenance methods available and to help you get the largest value for your property maintenance dollar.  We hope that you will call us at 615-973-9626 or email us at [email protected].  We look forward to serving you for many years to come.