Cape Seal A surface treatment where a chip seal is followed by the application of either slurry seal or micro-surfacing.

Channels (Ruts)Channeled depressions that sometimes develop in the wheel paths of an asphalt pavement.

Clinker A fused or partially fused by-product of the combustion of coal. Also includes lava and Portland Cement and partially vitrified slag and brick.

Coal Tar A dark brown to black cementitious material produced by the destructive distillation of bituminous coal.

Coarse Aggregate Aggregate retained on the 2.36 mm (No. 8) sieve.

Coarse-Graded AggregateOne having a continuous grading in sizes of particles from coarse through fine with a predominance of coarse sizes.

Cold In-place Recycling Train A unit consisting of a large milling machine towing a screening/crushing plant and pugmill mixer for the addition of asphalt emulsion and production of cold mix base.

Compaction The act of compressing a given volume of material into a smaller volume.

Consensus Properties Aggregate characteristics that must follow certain criteria to satisfy a Superpave mix design. Specified test values for these properties are not source specific but widely agreed upon. They include Coarse Aggregate Angularity, Fine Aggregate Angularity, Flat or Elongated Particles, and Clay Content.

Consistency The degree of fluidity of asphalt cement at any particular temperature. The con-sistency of asphalt cement varies with its temperature; therefore, it is necessary to use a common or standard temperature when comparing the consistency of one asphalt cement with another.

Corrugations (Washboarding) and Shoving A type of pavement distortion. Corrugation is a form of plastic deformation typified by ripples across the pavement surface. These distortions usually occur at points where traffic starts and stops, on hills where vehicles brake on the downgrade, on sharp curves, or where vehicles hit a bump and bounce up and down. They occur in asphalt layers that lack stability.

Crack and Seat A fractured slab technique used in the rehabilitation of PCC pavements that minimizes slab action in a jointed concrete pavement (JCP) by fracturing the PCC layer into smaller segments. This reduction in slab length minimizes reflective cracking in new HMA overlays.

Crack An approximately vertical random cleavage of the pavement caused by traffic loading, thermal stresses and/or aging of the binder.

Crack-Relief Layer A large stone, open graded asphalt mixture placed over a distressed pavement that minimizes reflective cracking by absorbing the energy produced by movement in the underlying pavement.

Crusher-Run The total unscreened product of a stone crusher.

Curing The development of the mechanical properties of the asphalt binder. This occurs after the emulsion has broken and the emulsion particles coalesce and bond to the aggregate.

Cutback Asphalt Asphalt cement that has been liquified by blending with petroleum solvents (diluents). Upon exposure to atmospheric conditions the diluents evaporate, leaving the asphalt cement to perform its function.

D Deep Strength Asphalt Pavement Pavements containing at least four inches of HMA over non-stabilized base courses.

Deflection Basin The idealized shape of the deformed pavement surface as a result of a cyclic or impact load as depicted from the peak measurements of five or more deflection sensors.

Deflection A load-induced, downward movement of a pavement section.

Rebound Deflection The amount of surface rebound when a load is removed.

Representative Rebound Deflection The mean value of measured rebound deflections in a test section, plus two standard deviations, adjusted for temperature and most critical period of the year for pavement performance.

Residual Deflection The difference between original and final elevations of the pavement surface resulting from the application to, and removal of, one or more loads from the surface.

Deflection Sensor The term that shall be used to refer to the electronic device(s) capable of measuring the vertical movement of the pavement; and, mounted in such a manner as to minimize angular rotation with respect to its measuring plane at the expected movement. Sensor types include seismometers, velocity transducers, and accelerometers.

Delivery Tolerances Permissible variations from the exact desired proportions of aggregate and bituminous material as manufactured by an asphalt plant.

Dense-Graded Aggregate An aggregate that has a particle size distribution such that when it is compacted, the resulting voids between the aggregate particles, expressed as a percentage of the total space occupied by the material, are less than 10%.

Densification The act of increasing the density of a mixture during the compaction process.

Design ESALThe total number of equivalent 80-kN (18,000-lb.), single-axle load applications (equivalent single axle loads) expected throughout the design period.

Design Lane The lane on which the greatest number of equivalent 80-kN (18,000-lb.) single axle loads (ESAL) is expected. This will normally be either lane of a two-lane roadway or the outside lane of a multi-lane highway.

Design Period The number of years from the initial application of traffic until the first planned major resurfacing or overlay. This term should not be confused with pavement life or analysis period. Adding hot mix asphalt overlays as required will extend pavement life indefinitely or until geometric considerations (or other factors) make the pavement obsolete.

Design Subgrade Resilient Modulus The value of the Subgrade Resilient Modulus (MR) used for designing the pavement structure. It is a percentile value of the subgrade resilient modulus test data distribution that varies with design ESAL.

Disintegration The breaking up of a pavement into small, loose fragments caused by traffic or weathering (e.g. raveling).

Distortion Any change of a pavement surface from its original shape. Drum

Mix Plant A manufacturing facility for producing asphalt paving mixtures that proportions the aggregate, then dries and coats the aggregate with a proportional amount of asphalt in the same drum. Variations of this type of plant use several types of drum modifications, separate (and smaller) mixing drums, and coating units (coater) to accomplish the mixing process. They are more suited for long runs of the same product.

Dryer An apparatus that will dry the aggregates and heat them to the specified temperatures.

Ductility The ability of a substance to be drawn out or stretched thin. While ductility is considered and important characteristic of asphalt cements in many applications, the presence or absence of ductility is usually considered more significant than the actual degree of ductility.

Durability The property of an asphalt pavement that represents its ability to resist disintegration by weathering and traffic. E Edge

Joint Cracks The separation of the joint between the pavement and the shoulder, commonly caused by the alternate wetting and drying beneath the shoulder surface. Other causes are shoulder settlement, mix shrinkage, and trucks straddling the joint.

Effective Thickness The ratio of the thickness of an existing pavement material compared to the equivalent thickness of a new HMA layer.

Emulsifying Agent or Emulsifier The chemical added to the water and asphalt that keeps the asphalt in stable suspension in the water. The emulsifier determines the charge of the emulsion and controls the breaking rate. ESAL (equivalent single axle loads) The effect on pavement performance of any combination of axle loads of varying magnitude equated to the number of 80-kN (18,000-lb.) single-axle loads that are required to produce an equivalent effect.

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