Simplified AASHTO Cracking Protocol

Crack classification and rating involves the assignment of type and severity to detected cracks. While the typical output for cracking of the LCMS is unclassified in order to allow the user to apply their own protocol, an optional Simplified AASHTO protocol output is also available.

PavemetricsTM Simplified AASHTO Protocol is based on the AASHTO PP44 standard (Quantifying Cracks in Asphalt Pavement Surfaces). The Simplified Protocol classifies and rates cracking using four crack types and four severity levels based on a user-customizable crack width. Reporting is according to five road zones: two outside wheel-paths, two wheel-paths and one in-between the wheel-paths zone.

Cracking types include: longitudinal, transverse (further divided into full length and partial length), ‘multiple’ and alligator cracking.

Longitudinal cracking reports 100% of the road cracking present (excluding transverse) in each of the five road zones using four severities. Extent of longitudinal cracking is based on length of affected road for each zone.

Multiple and Alligator cracking types are used to record pattern-based cracking. Alligator type is reported when there are three or more adjacent cracks in a given road zone. ‘Multiple’ type is used to indicate cracking instances with only two adjacent cracks in a given road zone. Extent of Alligator and Multiple is according to the length of affected road zone while severity is defined by maximum crack width.

Transverse cracking is reported using two types; complete, for cracks which are more than 75% of the lane width, and incomplete for cracks which are at least 25% of the lane width but less than 75%. Severity rating is according to the maximum crack width. Extent is reported as a count of the number of crack instances at each severity level.

AASHTO

PP67; Can quantify cracking (location, orientation, width, but not “type”*)
PP68; Can collect images of pavement surfaces

*Pavemetrics has developped a simplified Crack Classification Protocol, See MTQ Cracking Protocol

ASTM

D5340; Can be used for airport condition index surveys
D6433; Can be used for Roads and parking lot pavement condition index surveys

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