Crack Fill and Seal Coating
The procedure of crack filling consists of cleaning out all vegetation and dirt from major cracks ¼ inch or larger with a motorized crack cleaner. Next all the major cracks are blown out and the surface of the pavement where the cracks are is cleaned. Finally, the cracks are filled with a hot pour (rubberized) polymeric joint sealer to prevent moisture from getting under the asphalt pavement.
Benefits of Crack Filling
Crack filling should be done prior to any seal coat applications. If cracks are left unattended, water is able to penetrate to the base soaking and swelling the limestone, thus destroying its strength and load bearing capabilities. For a long-term repair, hot poured crack sealant should be used to prevent moisture penetration and extend pavement life.
The procedure of seal coating should always include crack filling as well. As described above the cracks are cleared of all vegetation and dirt and then the entire pavement surface is thoroughly cleaned of all dirt and debris. After cleaned, two coats of a commercial grade coal tar emulsion are applied to the asphalt pavement. After the second coat of sealer is applied, the sealed pavement must be clear of car traffic for a period of 24 hours. If the pavement has striping it will be re-striped within the 24 hour period during which it cannot be driven on.
Benefits of Seal Coating
Seal coating protects the asphalt against UV radiation or simply sunlight. The first and most obvious sign of degradation is the gradual change in the color of the asphalt from black to brown and finally to gray. Also, because the asphalt is oxidizing under UV radiation it loses its flexibility. When asphalt loses its flexibility it becomes brittle, begins to crack and break. A seal coating will restore the natural characteristics of asphalt as a flexible pavement. It will also protect the pavement against the harmful effects of salt, chemicals and petroleum products. Petroleum products cause most of the damage as witnessed by oil spots and gas spills. The reason for its poor resistance is that asphalt is a petroleum product. Naturally, gasoline and oils will dissolve directly into the asphalt, soften the structure and eventually cause major damage to asphalt pavements. The seal coat application will create a shield to protect the asphalt pavement from many of these harmful elements.