Between the Lines

by Katie Lee

Your asphalt is a major investment and asset. Maintain it well to protect both the life and the investment.

By Scott Milnes

Even the simplest luxuries we use on a daily basis can demand the most complicated maintenance. To many of us, parking lots are practically invisible, but to the facility manager with multiple or hundreds of locations, this can become an overwhelming budgetary concern when dealing with maintenance. No matter what your geographic location, a well-planned and budgeted preventative parking lot maintenance program will lower unexpected costs. Your asphalt is a major investment and asset. It should be maintained to prolong the life and hence the investment. Asphalt kept in good condition not only increases the value of the property, but also helps to eliminate possible safety hazards. Ignoring minor wear and tear on your parking lots can easily grow into major problems that will increase your costs and decrease customer retention. Keep in mind that parking lot maintenance is a large part of curb appeal. Potholes, cracks and loose debris are all negative reinforcements upon your customer’s first impression.

dentco parking lotsAcknowledge the Elements

Mother Nature is extremely hard on parking lots. Different regions face different environmental effects from sunlight, rain, snow, ice and wind abrasion. Other areas are prone to tornadoes, severe storms and even sinkholes. Not to mention salt, snowplows, chains, shovels, oil, gas and the list goes on and on. The seasonal elements alone tend to harden the pavement, making it more brittle and likely to crack. Another element that can be even more damaging to the asphalt is the friction from tires rolling across the surface. As if that is not enough, the sun alone will oxidize asphalt which hardens aggregates and extracts necessary oils that are essential in holding cement binders and aggregates together. Lastly, keep a close eye on irrigation systems, drainage systems, bird baths and areas that tend to collect water. Nothing accelerates the disintegration of asphalt faster that water. Once H2O penetrates a paved asphalt surface it begins to break up the base. Water penetrates pavement surfaces through small surface cracks and can easily develop into a pothole. Another problem magnified by water is raveling; this is a material defect and is intensified by vehicle traffic and fast moving water from rain or sprinklers. The longer these symptoms linger unattended, the greater the damage to the base and the greater the likelihood of higher repair costs.

Signs of wear and tear:

• Small, fragmented cracks

• Large cracks that flow with traffic direction

• Discoloration of blacktop or striping

• Cracked curbs, sidewalks or speed bumps

• Difference in surface texture

• Oil or antifreeze spots

• Loose asphalt

• Ruts or dips in surface

• Weeds or moss

• Birdbaths

Preventative Maintenance

The average life span of asphalt is about 15 years and it should be sealed every few years according to use and wear. Fixing birdbaths as soon as they appear will lessen the chance of water seeping through to the base and becoming a pothole. Asphalt is broken down by oil, gas, transmission fluid and other powerful chemical agents. If a piece of equipment or vehicle is leaking, or someone is washing out strong chemicals over the asphalt, it will have to be saw cut and repaired. All repair work should be saw cut, excavated, tack coated and paved with new hot mix asphalt. Cold patch is temporary at best. Leveling to move water is difficult considering the pre-existing design of your parking lot. To insure your satisfaction, the positive flow of drainage should be considered. Also check the existing and proposed grades. Sometimes simply lowering the grass along the edges of pavement will get rid of standing water. Overlaying an existing parking lot needs careful planning. If the existing surface is cracked through to the base and overlay will show reflective cracking in a short time.

Badly cracked areas should be stripped first. All pre-existing problems such as cracking, low spots, poor drainage and root damage should be resolved. A preventative maintenance program included in your budget will help keep your parking lot in good shape and minimize your long term costs.

Identifying Asphalt Stress

Although it is difficult to track discoloration over time, try to take pictures on a clear day so you have some type of reference to a dated color. Even after a 6-month period, you can notice the strong effects the sun has on your asphalt. As the oils are extracted from the base of the asphalt, the original deep black color will turn to a light black or dark grey. Oil spots are not necessarily signs of wear and tear or indicators of future problems. Needless to say, antifreeze, motor oil and other similar compounds definitely harm the durability of the asphalt cement binder which, in turn, weakens the surface directly.

Large Cracks

Probably more annoying to customers than anything else, large cracks can become an eyesore to your retail stores and provide a rough ride for cars. Large cracks are usually the sign of serious problems in the near future and should be dealt with immediately. Large cracks that are several feet apart and are rectangular or square in shape are referred to as block cracks. These cracks are usually not caused by a base defect. Block cracks tend to show up all over the surface area as opposed to specific regions. These cracks are specifically caused by the contraction of asphalt with a clay sub base. Large cracks that are parallel with traffic are referred to as transverse cracks. These are also usually caused by contraction of sub base materials (cement). Lastly, we have fatigue cracks that require repair or replacement depending on their size and location. After an overlay project or a new parking lot is completed, make sure you watch the birds after a good rain. Puddles will form in imperfect areas with dips in the asphalt and the birds love to show up for a nice bath. Bird baths are a true sign of an incorrect installation by the contractor, but they are also one of the easiest problems to repair.

Small Cracks

Small cracks can be a virtual road map to the future condition of your parking lot and if you pay attention to the warning signs, you can save money in the long run. Just like any other compound, asphalt contracts and expands and the aftermath is cracking. These surface cracks can be early warnings signs of a failing base. If your parking lot was a recent overlay project and cracks are appearing, it’s highly probable that the contractors didn’t use a strengthening fabric over the existing layer. Try to keep a close eye on new cracks and their frequency. It can make a big difference when it comes time to repair a surface versus a base.

Seal Coating

Seal coating is one of the best ways to initiate preventative maintenance for your asphalt. It prevents the damaging effects caused by the sun and water damage. Seal coating protects the surface and base materials from motor oil, gasoline, antifreeze, salt and various other damaging chemicals. The sun dries and extracts essential oil compounds from the asphalt and speeds up the processes of raveling and erosion. This can begin the rapid reduction in the overall thickness of your parking lot in less than 3 years. Surface sealing enhances the curb appeal of your facility while protecting and extending the life of your parking lot.

Crack Sealing

If caught in the early stages, crack sealing will successfully delay costly resurfacing. If done properly, it keeps water from entering and weakening the base or sub-base, while preserving the pavement adjacent to the cracks. This will prevent other debris from making its way into open cracks causing more compression-based damage. Proper attention to cracks will prevent problems from spreading and double the life of the pavement.

Catch Basins

Also known as storm basins, these drainage systems are used to collect pavement runoff and act as a junction for excess water. They are installed with a sump below that collects debris entering the catch basin through the grate opening. The trapped debris is then removed by hand or vacuum.

The Asphalt Institute

The Asphalt Institute is the international trade association of petroleum asphalt producers, manufacturers and affiliated businesses. Their mission is to promote the use, benefits and quality performance of petroleum asphalt, through engineering, research, marketing and educational activities, and through the resolution of issues affecting the industry. To learn more, visit their website at

Ready to Evaluate Your Parking Lot Maintenance Program?

If your retail stores or facilities are experiencing quality assurance issues, too many liability cases or simply have trouble completing parking lot specifications for national formats, you might want to consider calling a national ESM company. A parking lot management program could improve your customer experience, reduce your overall expenses, eliminate the worries of liability and provide a better customer experience.

— Scott Milnes is president of DENTCO, the first Exterior Services Management® (ESM) company. Milnes has managed the operations at DENTCO for more than 10 years and the company has doubled in size during his tenure. DENTCO offers 30 years of online portfolio management for snow and ice control, parking lot maintenance, landscaping, irrigation and other exterior services. Email the author at [email protected].

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