Potholes are the most common form of asphalt failure that require immediate repair and/or asphalt replacement. Potholes are open holes where the asphalt has not only cracked but broken away and separated from a section of the asphalt mat, creating a void and exposed base rock.
There are several potential causes for the formation of potholes. The following can all be root causes or combination causes for their formation:
Asphalt is too thin in the area of failure: Thin asphalt, less than 1” thick, is susceptible to premature failure under repeat traffic loadings.
Age and brittleness: Once asphalt has reached a certain age, especially if it has not been properly maintained, it can become brittle and rapidly deteriorate. Part of this deterioration is the potential for high severity potholes.
Poor drainage: Asphalt that holds standing water, especially in areas of traffic loadings such as wheel paths, is much more likely to form fatigue cracking that will eventually lead to potholes. Once potholes are formed in low lying areas, the water will continue to make them more severe if not addressed.
Luckily, potholes in asphalt can be fixed relatively easily via localized patching. How the patch is completed will determine if it will hold up to new traffic loadings and weather, or if it will fail again.
To properly patch a pothole, the following steps should be taken.
Sawcut the perimeter of the failure to the full depth of the asphalt. Make sure the sawcut encompasses the entire area of failure, including fatigued areas outside of just the pothole. Otherwise, a new pothole will form directly next to your new patch.
Apply liquid emulsified Tack Coat to the base material.
Remove the old asphalt from the failed area and compact the existing base material.
Rake in hot mixed asphalt to encompass the entire removal area.
Roll and compact the mixture while it is still hot to meet existing elevation of adjacent asphalt.
Following these steps will ensure you are making a lasting, quality repair to your asphalt pavement.
Infrared patching of asphalt pavement, often referred to as cold weather patching or seamless cold weather asphalt repair, is a temporary solution to pavement failures and an alternative to cold patch asphalt. The process consists of heating up an area of pavement to make it workable, raking the existing asphalt material (sometimes adding some new) to cover any inconsistencies, and rolling to finish.
Elevation adjustments around valve covers and manholes
Bonding speed bumps to existing asphalt surfaces
A means of repair in a newly installed asphalt overlay where a raveled area can be heated and rolled so as not to create new seams
However, infrared patching is NOT a permanent repair and is NOT a recommended solution to most asphalt failures. Asphalt typically fails due to a combination of vehicle/truck loading, the thickness of the pavement section, poor drainage, and/or poor subgrade conditions. In these conditions, removal and replacement of the failed asphalt is the best solution.
Oxidized and raveled pavement – Not enough binder left in surface to “rejuvenate” and hold together without post-patch raveling
Thin asphalt sections (2” or less such as those in Florida) – Since Infrared is a true surface-only repair, a failed pavement cannot benefit from this type of repair. It should be replaced in the areas of failure to avoid future rework
Exposed potholes – exposed potholes require removal of the pavement surrounding the pothole, compaction of the existing base material, and import of new asphalt to complete the permanent repair. Anything less will deliver a sub-standard product
Areas with gate-loops, areas within 2-ft of wood or metal, parking garages, dumpsters
On surfaces that have been sealed or chip sealed with coal tar or other emulsions
Alligator cracked or fatigue cracked asphalt – These failures are structural in nature and must be addressed by a permanent means of removal and replacement
Areas of heavy loading – Infrared patching adds no new strength and can actually weaken the patch area