Seal Coating Tucson

Understanding Asphalt Maintenance, Asphalt Repair and Seal Coating

Eagle Rocks Excavatings expert team of asphalt seal coating professional located right here is Tucson Arizona has the knowledge to extend the life of asphalt highways, public and private roads, and parking lots through properly timed and applied seal coating, which intern saving money by significantly reduces repair costs through sealcoating maintenance.

Research has demonstrated that properly applied (properly timed) seal coating can save the owner of a property 65% or more- over the life of a hot mix asphalt pavement. But what does seal coating actually do that result in this substantial savings?

To understand how seal coating works, it is necessary to understand the nature of the asphalt pavement itself. Because of its excellent waterproofing, flexibility, and adhesive properties to bind and hold the aggregates in the pavement, asphalt has been used extensively for paving and road construction. Prior to the advent of asphalt as a paving material, roads were constructed by spreading graded aggregates over a road bed. These roads worked well as long as the aggregates remained in place and stayed dry. Naturally, these roads needed constant repair. The aggregates would shift under the traffic and the roads load carrying ability was severely damaged when it rained. The aggregates would absorb water, swell and lose its strength. But spraying asphalt on the surface of the aggregates solved this problem somewhat. Asphalt paving technology gradually evolved and today the vast majority of all roads are constructed using asphalt as the binding material for the aggregates. Due to its waterproofing properties, asphalt protects the aggregates from absorbing water, thus preserving their strength and load-carrying capacities. Today’s asphalt pavement is a mixture of stone aggregate and mineral filler combined with 5% to 6.5% asphalt binder or asphaltic cement. The strength of an asphalt pavement is directly related to the pavement design from the ground up. The asphalt pavement that people see is only the “roof’, so to speak, of the entire pavement. This “roof” covers a bed of graded aggregates of varying depths according to ground conditions as well as traffic requirements. This base of aggregate is what really carries the load of the traffic. The same theory applies to off-street parking lots or drive ways. A firm resilient surface that provides a roof over the aggregate base will keep the pavement bed dry. It is important to have an elastic characteristic in this pavement so that it can expand and contract and still remain intact.

Why seal asphalt?
In spite of its excellent adhesive and waterproofing properties asphalt has some serious drawbacks that relate to its chemical makeup. Asphalt is a very complex mixture of thousands of chemicals which are predominately open chain (aliphatic) in structure with a considerable degree of un-saturation within their molecular structure. The open chain provides easy access to weather, salts, and free radicals, which disintegrate the asphaltic molecules. As the asphaltic molecules disintegrate, the asphalt in the pavement loses much of its original properties, such as binding and waterproofing. The first visual sign of this phenonemen is a progressive change in the color of asphalt pavement from rich black to brown to gray. Furthermore, asphalt, being a byproduct of the petroleum distillation process, is easily dissolved by other products that are also are derived from the petroleum, such as oils, fats, grease, mineral spirits etc. The reason is quite logical: As petroleum, these various products existed together for millions of years. It is only through the petroleum refining process that they are separated for various uses. Because these individual products come from the same source, they have a natural affinity for one another and when put in contact with each other will try to join together again. So when automotive oil or gasoline (both petroleum distillates) leak onto an asphalt pavement, they will work to easily dissolve the similar chemicals in asphalt. These problems are primarily associated with off-street pavements such as parking lots minor streets, airport aprons or runways, service stations, and home driveways, which carry low levels of traffic.

Roads, having the advantage of continuously rolling traffic, do not need protection because the rolling action of the traffic steadily brings the lower layers, rich in asphalt or bitumen, to the surface and “kneads” the oxidized surface layers back into the pavement. Off-street pavements do not have the advantage of this kneading action. Eventually all the asphalt binder is exhausted and the aggregates begin to unravel due to the absence of the binding cement or bitumen. This happens to all pavement including roads. The rate of pavement deterioration depends upon the traffic volume as well as climatic conditions. The next step in the deterioration process is the development of minor cracks which widen and deepen with time. The surface layers of off-road pavements are under continuous attack from the weather and other destructive elements, eventually developing minor surface cracks. If the cracks are not repaired at this stage, water seeps into the base courses and damages the pavement’s load bearing capacity. This is evidenced by rutting, shifting, shoving, and alligatoring. The pavement then must be either overlaid or completely removed and reinstalled, depending on the condition. The damage will continue if proper protective actions are not taken. So it would be logical to conclude that off- street pavements can be preserved by a ‘protective coating” that resists attack by the elements that destroy the asphalt in the first place. Seal coating asphalt can be compared to painting wood. If you leave un- treated wood in the sun and exposed to the elements it will very shortly turn black and start decomposing. In the same way un-sealed asphalt will turn grey and start un-raveling and soon the surface will be covered in the ‘fines” or the smallest of the aggregates. You will notice them making a crunching noise under your feet as you walk across the parking lot. Cleaning and seal coating at this point will slow the un-raveling process down and save real dollars for the property owners. Unsealed pavements will require repairs starting with the second year and could require an overlay as often as every ten years. Cost savings over the life of the pavement will be a substantial 65% if the pavement is maintained regularly. The words patching, crack sealing, and seal coating, must become a regular part of your maintenance schedule to achieve this cost savings. In addition to the savings you will also notice that customers prefer to shop at your shopping center when the asphalt is regularly maintained. This will increase the bottom line for everyone. If you live in an HOA and must maintain the streets you will also benefit from this maintenance in the same manner. Your insurance will cost less and your property values will be higher when the streets are regularly maintained. Curb appeal is universal.

Please don’t hesitate to call us today for a free estimate and asphalt evaluation. Whether your job is large or small our team of professionals will correctly recommend the work that needs to be completed and demonstrate how we construct it to last. Eagle Rock Excavating 520-514-2779

April 2017
« Dec