Overlay
Asphalt overlay is the process of applying a new layer of asphalt over a deteriorating sub layer. Instead of completely tearing up an aging or unusable surface, asphalt overlay projects use the existing surface as the base for the new asphalt pavement. However, in certain circumstances, certain asphalt surfaces considerable damage, potholes, rutting, large cracks, or growing expansions will need to be milled before the process of overlaying a new surface can begin.
The Steps In Asphalt Overlaying
The Assessment of Existing Asphalt
Only some existing asphalt surfaces are usable for an asphalt overlay project. Like we mentioned previously, if a surface has extensive structural damage, then the entire subsurface will need to be ripped up to make a new foundation. Additionally, certain asphalt surfaces may not be draining water correctly or they may not be suitable for an asphalt overlay because the surface may need to be regarded to handle water more effectively.
Milling the Asphalt
If necessary we may need to mill or remove the top layer of an asphalt surface that might be unsuitable as a sub-surface for an asphalt overlay. The layer with sustained damage must be removed to ensure that when the new asphalt is applied it is able to adhere with an even bond and to maintain a level surface. Our machines grind down from 1″ to 3″ depending on the existing wear of the asphalt surface. From there, the surface material will be hauled to an asphalt recycling plant where it can be integrated into new asphalt mix designs.
Base Repair
In some circumstances, the base of an asphalt surface may need to be replaced in areas where significant damage has formed. In order to make sure a severe problem will not form again the base of the asphalt surface will be rebuilt using multiple lifts of aggregate and asphalt.
Pave Surface
After the existing asphalt surface has been prepped, the new asphalt overlay can be paved on top. Depending on the thickness of the existing surface will determine the amount of asphalt overlay applied to the surface. However, typically the new surface is somewhere between 1-2”.
Asphalt Overlay on Concrete
As with asphalt, In some circumstances, asphalt overlay can be applied to an existing concrete paved surface. Like asphalt, when a concrete surface deteriorates there is not an easy option to repave the surface with concrete without ripping the surface up entirely. Asphalt overlay is an option for some asphalt surfaces that are in disrepair, but paving asphalt over concrete comes with some catches.
Concrete paved surfaces are not compressed and compacted like asphalt is, rather the concrete adheres and fills voids and irregularities with the soil and sub grade beneath it. Because concrete is a harder surface that does not have as much give as asphalt, expansion joints are cut into the surface to help prevent cracking from seasonal expansion.
When you pave over concrete with asphalt, sometimes over time potential expansion of the joints can create cracks and bumps. However, cracks in the asphalt along expansion joints will not cause the surface to fail, but it will need to be crack sealed over time to maintain a resistance to water and to maintain integrity.
