COMMON ASPHALT PROBLEMS part1
Posted by Jesse Willoughby on Thu, Oct 15, 2009 @ 11:10 AM
Cracking Repairable with Sealant or Fill
Asphalt cracks that form in the pavement surface can allow many harmful substances - including water, salts and engine oils - into the base and subgrade, effectively leading to the failure of the pavement surface. There are many types of asphalt cracking and many causes for these differing problems. In many cases, cracks develop because of the expansion or contraction of the base or subgrade or because of voids that form between the layers or courses of pavement. These cracks can form randomly or in the following specific forms. In all cases, if repaired while still within ¼" to ½", these cracks are easily repaired and maintained.
Transverse cracking
Transverse cracking, or cracks that occur across the pavement surface about perpendicular to the parking lot center, are often caused by the asphalt expansion and contraction due to temperature changes and or this movement due to asphalt aging. Initially, these cracks will be relatively equally spaced depending on traffic but will eventually become more prevalent in the parking lot or roadway. In some cases, as these cracks become more prevalent, block cracking forms where the Transverse cracks develop into squares throughout the pavement.
Also, these cracks may extend either entirely or partially across the pavement area or roadway.
Transverse cracks begin as "hairline" cracks - or cracks up to ¼" wide - but will widen to ½" or wider with age and lack of proper repair. Because these cracks are allowing water into the pavement base and subgrade, lack of proper asphalt repair or maintenance will lead to more cracks developing parallel to the original transverse cracking. If not properly repaired, these transverse asphalt cracks will be appear with greater prevalence and the cracks will become wider; eventually, the cracks will be so prevalent that entire areas will be broken or "alligatored" (see Alligatoring section) leading to a more serious, cutting and patching asphalt repair.
Next we'll cover longitudinal asphalt cracking...
Source: U.S.Pavement Services