The biggest contributor to asphalt damage and deterioration is – fortunately and unfortunately – the easiest and cheapest to prevent. The reason it’s unfortunate is because most property owners and managers have a reactionary mindset with regard to pavement maintenance, rather than a preventative one. This is a truly classic example where an ounce of prevention is worth a pound of cure. If you’re going to have anything done to your parking lot, having a qualified contractor perform crack filling is by far the highest priority.
According to the Asphalt Institute’s Mike Sonnenberg, the three largest contributors to asphalt damage are “water, water, and water.” Moisture penetration through the surface to the pavement sub-base and sub-grade can cause an array of new and more costly problems to the surface pavement including potholes and widespread cracking or “alligator” cracking. Furthermore, the sub-base can become damaged. The remedy for each of these failures becomes progressively and exponentially more expensive: (1) crack filling is cheap (2) pavement patching is more expensive (3) sub-base rehabilitation is more expensive still.
An appropriate course of action is as follows:
- Quickly identify new surface cracks and address them at the latest within one or two seasons after cracks appear. So if cracks appear in the spring, they should be filled in the fall.
- The most appropriate time to fill cracks is in cool weather – either in the spring or the fall – because the crack width is at its median point. Asphalt material expands in hot weather and contracts in cold weather, so in the spring and fall, cracks will not be at their widest or narrowest. If cracks are filled in the summer when cracks are at their narrowest, the amount of material in the crack may not be sufficient to keep the crack sealed when the pavement contracts in the winter. Likewise, if we fill cracks in the winter, we may have too much material such that in the summer, the material will bulge out and be increasingly likely to be torn out by crossing vehicle traffic. In the Puget Sound, this is not as critical because we don’t experience the wide temperature swings between seasons like other places such as the Midwest. Consequently, the variance in crack openings is not as large.
- Candidates for crack filling are those between 1/8th of an inch and 1.5 inches. Cracks narrower than 1/8th of an inch are too narrow to have the material appropriately penetrate the crack and adhere to the inner sidewall. Cracks wider than 1.5″ should be filled with a Class G hot mix asphalt or a polymer.
- Cracks should be cleaned and dry before they are filled with the crack filling material.
- A hot-apply crack filler is the most effective product. We use a product call DuraFil.
- The crack should be filled to flush with the pavement surface or slightly recessed, up to ¼ of an inch below grade and smoothened with a squeegee or torch. If too much material is applied and it bulges at the top, it has a higher likelihood of being torn out by crossing vehicle traffic, particularly during hot days.
- Crack filling is appropriate for solitary cracks but not for widespread cracking or what is known as “alligator” cracking. Those areas require removal and replacement patching.
Under most circumstances, crack filling is going to cost between $1 and $2 per lineal foot for cleaning and filling. This modest cost can potentially prevent thousands of dollars of rehabilitation or reconstruction of the pavement layer and the sub-base and sub-grade layers from asphalt damage. We strongly recommend it.