The Council for Scientific and Industrial Research in South Africa offers similar methods for the repair of potholes. In winter, the throw-and-roll technique may be the only available option. The FHWA suggests the best patching techniques, at times other than winter, are spray injection, throw-and-roll, semi-permanent, or edge seal procedures. 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. 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. 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. Pothole patching methods may be either temporary or semi-permanent. Sealing the cracks through asphalt crack filling can help prevent potholes and further pavement damage. Sealing Asphalt Cracks Īccording to the US Federal Highway Administration, 70% of unsealed cracks become potholes within 3 years. Utility cut management Įaton, 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. 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. Good crack control prevents water penetration into the pavement soil structure. ![]() Adequate crowns promote drainage to the sides. 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. Drainage ĭrainage structures, including ditching and storm sewers are essential for removing water from pavements. 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. Pavement condition monitoring can lead to timely preventive action. Sealing Asphalt Cracks Survey of pavements Īt-risk pavement are more often local roads with lower structural standards and more complicating factors, like underground utilities, than major arteries. Providing adequate drainage structures 3. Surveying of pavements for risk factors 2. The following steps can be taken to avoid pothole formation in existing pavements: 1. Pavement defects and cracks left unmaintained and unsealed so as to admit moisture and compromise the structural integrity of the pavement Failures at utility trenches and castings ( manhole and drain casings) 4. Insufficient pavement thickness to support traffic during freeze/thaw periods without localized failures 2. Potholes may result from four main causes: 1. ![]() Serious road accidents can occur as a direct result, especially on those roads where vehicle speeds are greater. If they become large enough, damage to tires, wheels, and vehicle suspensions is liable to occur. Potholes can grow to several feet in width, though they usually only develop to depths of a few inches. ![]() In the spring, thaw of pavements accelerates this process when the thawing of upper portions of the soil structure in a pavement cannot drain past still-frozen lower layers, thus saturating the supporting soil and weakening it. In areas subject to freezing and thawing, frost heaving can damage a pavement and create openings for water to enter. Eventually, chunks of pavement between the fatigue cracks gradually work loose, and may then be plucked or forced out of the surface by continued wheel loads to create a pothole. Potholes form progressively from fatigue of the road surface which can lead to a precursor failure pattern known as crocodile (or alligator) cracking. Water weakens the soil beneath the pavement while traffic applies the loads that stress the pavement past the breaking point. A deep pothole with a nearby patched area on New York City's Second AvenueĪccording to the US Army Corps of Engineers's Cold Regions Research and Engineering Laboratory, pothole formation requires two factors to be present at the same time: water and traffic.
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