Alligator cracking is often used as our measure of failure. When pavement is failing we usually visualize area of alligator cracking and maybe a few potholes. Alligator cracking begins on the bottom of the pavement and is the result of de-flection or bending of the pavement under wheel load.

Plant mixed asphaltic concrete, well graded, crushed aggregate with a smooth surface texture.

Bleeding or flushing is the defect where the excess asphalt cement binder in the mix comes to the surface as “free” or excess material, making the surface slick and dangerous.

A structural base layer consisting aggregate bound or cemented by portland cement.

A mixture of aggregates and asphalt cements applied as an aggregate seal coat. The asphalt cement is sprayed on the pavement and then aggregate sprinkled on the surface.

An emulsified non-asphaltic by-product of the coal coking process which is sometimes used as surface seal. Subject to extensive shrinkage and cracking, normally not recommended unless mandatory for gas spillage resistance.

Localized pavement repairs to correct structural deficiencies. The pavement is saw-cut in rectangular patterns and all material within the rectangle is removed and replaced.

Fabrics refer to a crack retardant fabric membrane placed on the existing surface of existing pavement under a new overlay.

Usually a soft base SS1-H asphalt emulsion containing un-graded fillers (such as clay. slate polyethylene fibers, celluloid and/or asbestos).

A full range of emulsified asphalt surface seals, usually consisting of softer grade asphalts such as SS1-H and fillers like clay, slate, polyethylene fibers, sands, etc.

A spray applied emulsified asphalt sea that is used as a seasonal winterizer to protech asphalt cements. Usually consisting of soft-based SS1-H lasting only one season.

A design methodology where the asphalt material provides the majority of the pavement structural support.

Any material placed on the surface of an existing pavement and “sandwiched” under a new pavement layer.

The placement of asphaltic concrete mix over an existing asphaltic concrete or portland cement concrete surface.

Aggregate with cement binder, characterized by gray/white color. Relatively smooth, uniform concrete surface having few exposed aggregates.

A spray applied asphalt product used on the surface of a new aggregate base to promote bonding between the asphalt surfacing and aggregate base layers.

Raveling of the asphalt pavement is the gradual roughening of the surface texture. The fine sandy particles are “washing” away leaving the pavement with course rock on the surface and a much rougher texture that originally constructed.

The phenomenon that occurs to create cracks in new thin overlays that are identical to cracks that were were present in the existing pavement.

Rutting is a defect that occurs at the wheel path and is a permanent deformation of dip at the surface as the result of a moving load. Rutting can be the result of excessive stresses on the soil layer or an unstable asphalt concrete mix, and is a structural failure that must be corrected.

Seal coats or maintenance seals are generic terms for any of a number of surface coatings such as coal tar, filled asphaltic sealers, Gilsonite seals, etc., all aimed at protecting against moisture intrusion and raveling.

Slurry Surfacing is an asphalt slurry mixture made from closely graded fine aggregate, emulsified asphalt and water, all carefully calibrated and mixed to forma a mortar-like compound.

An emulsified asphalt, water and aggregate mixture with graded aggregates of No. 8 maximum size added at the job site.

An emulsified asphalt, water and aggregate of No. 4 maximum size with aggregates added at the job site. Type II is commonly referred to as “highway slurry seal”.

An emulsified asphalt, water and aggregate of 3/8" maximum size with aggregate added at the job site. Type III is not commonly used for anything but major highways and rural roadways.

A spray applied asphalt product used to promote Bonding between new asphalt concrete and other Surfaces. Most commonly used between asphalt Concrete pavement layers.

Cracking of this nature is related to shrinkage. The shrinkage can be the result of temperature or at rare instances the underlying soil. It is a non-structural defect and is more likely to form as the pavement hardens through oxidation. The major problem with this cracking is that it is unsightly and allows water into the soil layers, and if unsealed promotes structural failure.