Pothole

A pothole is a pot-shaped depression in a road surface, usually asphalt pavement, where traffic has removed broken pieces of the pavement. It is usually the result of water in the underlying soil structure and traffic passing over the affected area. Water first weakens the underlying soil; traffic then fatigues and breaks the poorly supported asphalt surface in the affected area. Continued traffic action ejects both asphalt and the underlying soil material to create a hole in the pavement.

A pothole is a pot-shaped depression in a road surface, usually asphalt pavement, where traffic has removed broken pieces of the pavement. It is usually the result of water in the underlying soil structure and traffic passing over the affected area. Water first weakens the underlying soil; traffic then fatigues and breaks the poorly supported asphalt surface in the affected area. Continued traffic action ejects both asphalt and the underlying soil material to create a hole in the pavement. ==Gallery== File:Asphalt deterioration.jpg|Crocodile cracking showing moisture seepage, a sign of a weakened soil structure beneath the failed asphalt File:Pothole in Villeray, Montréal.jpg|Detail of pothole, showing presence of water in soil structure, on a road in Montréal, Québec File:Newport Whitepit Lane pot hole.JPG|Example of a pothole reappearing on a newly patched roadway, also showing the transition between crocodile cracking and the pothole, with water dried up, in a road on the Isle of Wight Image:Banbury's Bretch Hill Pothole, 2010.png|Small potholes, showing isolated failures of the pavement and its subsurface structure, in a road in Banbury, UK File:Dirtroadpotholes.JPG|Potholes on an unpaved road in Sweden ==Prevention== The following steps can be taken to avoid pothole formation in existing pavements: 1. Surveying of pavements for risk factors 2. Providing adequate drainage structures 3. Preventive maintenance 4. Utility cut management 5. Sealing asphalt cracks ===Survey of pavements=== At-risk pavement are more often local roads with lower structural standards and more complicating factors, like underground utilities, than major arteries. Pavement condition monitoring can lead to timely preventive action. Surveys address pavement distresses, which both diminishes the strength of the asphalt layer and admits water into the pavement, and effective drainage of water from within and around the pavement structure. ===Drainage=== Drainage structures, including ditching and storm sewers are essential for removing water from pavements. Avoiding other risk factors with good construction includes well-draining base and sub-base soils that avoid frost action and promote drying of the soil structure. Adequate crowns promote drainage to the sides. Good crack control prevents water penetration into the pavement soil structure. ===Preventive maintenance=== Preventive maintenance adds maintaining pavement structural integrity with thickness and continuity to the mix of preventing water penetration and promoting water migration away from the roadway. ===Utility cut management=== Eaton, et al., advocate a permitting process for utility cuts with specifications that avoid loss of structural continuity of pavements and flaws or failures that allow water penetration. Some municipalities require contractors to install utility repair tags to identify responsible parties of the deteriorated patches. ==Repair== Pothole patching methods may be either temporary or semi-permanent. Temporary patching is reserved for weather conditions that are not favorable to a more permanent solution and usually uses a cold mix asphalt patching compound placed in an expedient manner to temporarily restore pavement smoothness. Semi-permanent patching uses more care in reconstructing the perimeter of the failed area to blend with the surrounding pavement and usually employs a hot-mix asphalt fill above replacement of appropriate base materials. The Federal Highway Administration (FHWA) offers an overview of best practices which includes several repair techniques; throw-and-roll, semi-permanent, spray injection, and edge seal. The FHWA suggests the best patching techniques, at times other than winter, are spray injection, throw-and-roll, semi-permanent, or edge seal procedures. In winter, the throw-and-roll technique may be the only available option. The Council for Scientific and Industrial Research in South Africa offers similar methods for the repair of potholes. ===Materials=== Asphaltic patch materials consist of a binder and aggregate that come in two broad categories, hot mix and cold mix. Hot mixes are used by some agencies, they are produced at local asphalt plants. The FHWA manual cites three types of cold mixes, those produced by a local asphalt plant, either 1) using the available aggregate and binder or 2) according to specifications set by the agency that will use the mix. The third type is a proprietary cold mix, which is manufactured to an advertised standard. ===Throw-and-roll repair=== The FHWA manual cites the throw-and-roll method as the most basic method, best used as a temporary repair under conditions when it is difficult to control the placement of material, such as winter-time. It consists of: Placing the hot or cold patch material into a pothole Compacting the patch with a vehicle, such as a truck Achieving a crown on the compacted patch of between 3 and 6 mm This method is widely used due to its simplicity and speed, especially as an expedient method when the material is placed under unfavorable conditions of water or temperature. It can also be employed at times when the pothole is dry and clean with more lasting results. Eaton, et al., noted that the failure rate of expedient repairs is high and that they can cost as much as five times the cost of properly done repairs. They advocate this type of repair only when weather conditions prevent proper techniques. Researchers from the University of Minnesota Duluth have tested mixing asphalt with iron ore containing magnetite which is then heated using ferromagnetic resonance (using microwaves at a specific frequency) to heat the mixed asphalt. The mixture used a compound of between 1% and 2% magnetite. The group discovered that material could be heated for a patch to in approximately ten minutes which then applied a more effective repair and drove out moisture which improved adhesion. File:Pothole throw-and-roll material placement.png|Throw-and-roll pothole repair procedure—material placement File:Pothole throw-and roll compaction of patch.png|Throw-and-roll pothole repair procedure—compaction of patch ===Semi-permanent repair=== The FHWA manual cites the semi-permanent repair method as one of the best for repairing potholes, short of full-depth roadway replacement. It consists of: 1. Removing water and debris from the pothole 2. Making clean cuts along the sides of prospective patch area to assure that vertical sides of the repair are in sound pavement (Eaton, et al., recommend a bituminous tack coat in the open cavity, prior to placement of patch material.) 3. Placing the hot or cold patch mix material 4. Compacting the patch with a device that is smaller than the patch area, e.g. vibratory rollers or a vibratory plate While this repair procedure provides durable results, it requires more labor and is more equipment-intensive than the throw-and-roll or the spray-injection procedure. File:Pothole semi-permanent repair cut edges.png|Semi-permanent pothole repair procedure—straightening edges using hand-held pavement saw File:Pothole semi-permanent repair vibratory compactor.png|Semi-permanent pothole repair procedure—compaction using vibratory-plate compactor File:Man on roller, Campsie Road, Omagh - geograph.org.uk - 1715261.jpg|Semi-permanent pothole repair procedure—small vibratory compactor for larger repairs ===Spray-injection repair=== The FHWA manual cites the spray-injection procedure as an efficient alternative to semi-permanent repair. It requires specialized equipment, however. It consists of: 1. Blowing water and debris from the pothole 2. Spraying a tack coat of binder on the sides and bottom of the pothole 3. Blowing asphalt and aggregate into the pothole 4. Covering the patched area with a layer of aggregate This procedure requires no compaction after the cover aggregate has been placed. File:Pothole spray-injection equipment.png|Spray-injection device for pothole repair—truck and trailer unit in the United States File:Operation nids-de-poule.JPG|Spray-injection device for pothole repair—all-in-one repair unit in Montreal, which allows the operator to work from the comfort and safety of the cab File:Pothole patching.jpg|Spray-injection device for pothole repair—all-in-one repair unit in the Czech Republic ===Edge seal repair=== The FHWA manual cites the edge seal method as an alternative to the above techniques. It consists of: 1. Following the "throw-and-roll" steps 2. After the repaired section has dried, placing a ribbon of asphaltic tack material on top of the patch edge, overlapping the pavement and the patch 3. Placing sand on the tack material to prevent tracking by vehicle tires In this procedure, waiting for any water to dry may require a second visit to place the tack coat. The tack material prevents water from getting through the edge of the patch and helps bond the patch to the surrounding pavement. ===Efficacy of repair methods=== An FHWA-sponsored study determined that the "throw-and-roll technique proved as effective as the semi-permanent procedure when the two procedures were compared directly, using similar materials". It also found the throw-and-roll procedure to be generally more cost-effective when using quality materials. It further found that spray-injection repairs were as effective as control patches, depending on the expertise of the equipment operator. ===Visual art=== Two artists, Jim Bachor of Chicago and Baadal Nanjundaswamy of Bengaluru, India, have used artwork as a commentary on potholes by placing mosaics (depicting ice cream in various manifestations) or sculpture (in the form of a crocodile) in potholes. Elsewhere, activists in Russia used painted caricatures of local officials with their mouths as potholes, to show their anger about the poor state of the roads. In Manchester, England, a graffiti artist painted images of penises around potholes, which often resulted in them being repaired within 48 hours. Activists in Spain have also got quick fixes with penis graffiti. ===Song=== The Beatles song "A Day in the Life" references potholes. John Lennon wrote the song's final verse inspired by a Far & Near news brief, in the same 17 January edition of the Daily Mail that had inspired the first two verses. Under the headline "The holes in our roads", the brief stated: "There are 4,000 holes in the road in Blackburn, Lancashire, or one twenty-sixth of a hole per person, according to a council survey. If Blackburn is typical, there are two million holes in Britain's roads and 300,000 in London." ===Television=== In the Seinfeld episode The Pothole, George discovers that he has lost his keys, including a commemorative Phil Rizzuto keychain that says "Holy Cow" when activated. He then retraces his steps, and returns to a street where he had jumped over a pothole, which is now filled in with asphalt. The "Holy Cow" phrase is heard when a car runs over it. ===News=== In December 2025, the BBC current affairs programme Panorama broadcast an episode titled "The Pothole Problem", in which reporter Richard Bilton investigated the rising number of potholes across the United Kingdom, the injuries and vehicle damage they cause, and the difficulties local authorities face in keeping up with repairs. ==References==

Text derived from https://en.wikipedia.org/w/index.php?oldid=1376575477 under CC BY-SA 4.0; modifications have been made.