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Terms |
Definitions |
| A |
Asphalt (Asphalt cement) |
A dark brown to black cementitious material in which the prodominating constituents are bitumens, which occur in nature or are obtained in petroleum processing. Asphalt is a constituent in varying proportions of most crude petroleum and used for paving, roofing, industrial and other special purposes.
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Asphalt Emulsion Slurry Seal |
A mixture of slow-setting emulsified asphalt, fine aggregate, and mineral filler with a slurry consistency.
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Asphalt Leveling Course |
A course of hot mix asphalt of variable thickness use to eliminate irregularities in the contour of and existing surface prior to placing the subsequent course.
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Asphalt Pavement Structure |
A pavement structure that is designed and constructed so that all courses above the subgrade are asphalt concrete.
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Asphalt Pavements |
Pavements consisting of a surface course of asphalt concrete over supporting courses such as asphalt concrete bases, crushed stone, slag, gravel, portland cement concrete, brick, or block pavement.
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Alligator Cracks |
Interconnected cracks forming a series of small blocks resembling an alligator's skin or chicken-wire, and caused by excessive deflection of the surface over unstable subgrade or lower course of the pavement.
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| B |
Base Course |
The layer in the pavement system immediately below the binder and surface courses. it usually cojnsists of crushed stone, although it may consist of crushed slag or other stabilized or unstabilized material.
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Binder Course |
The layer in the pavement system immediately below the binder and surface courses. It usually cojnsists of crushed stone, although it may consist of crushed slag or other stabilized or unstabilized material.
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Bitumen |
A class of black or dark-colored (solid, semisolid, or viscous) cementitious substances, natural or manufactured, composed principally of high molecular weight hydrocarbons, of which asphalts, tars, pitches, and asphaltites are typical.
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| C |
Coal Tar |
A dark brown to black cementitious material produced by the destuctive distillation of bituminous coal.
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Compaction |
The act of compressing a given volume of material into a smaller volume.
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Crack |
An approximately vertical random cleavage of the pavement caused by traffic loading, thermal stresses and/or aging of the binder.
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Curing |
The development of mechanical properties of the asphalt binder. This occurs after the emulsion has broken and the emulsion particles coalesce and bond to the aggregate.
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| E |
Expansive Potential |
The potential of a soil to expand (increase in volume) due to absorbtion of moisture.
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| F |
Finished Grade |
The final grade created as part of the project. |
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Footing |
A portion of the foundation of a structure that transmits loads directly to the soil. |
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Foundation |
The lower part of a structure that transmits loads to the soil or bedrock. |
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Frost Depth |
The depth at which the ground becomes frozen during the winter season. |
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Full-depth Asphalt Pavement |
The term full-depth certifies that the pavement is one in which asphalt mixtures are employed for all courses above the subgrade or improved subgrade. A full-depth asphalt pavement is placed directly on the prepared subgrade. |
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| G |
Grade |
The soil prepared to support a pavement structure or a pavement system. It is the foundation of the pavement structure. |
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Grade Beam |
A foundation element or wall, typically constructed of reinforced concrete, used to span between other foundation elements such as drilled piers. |
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Groundwater |
Subsurface water found in the zone of saturation of soils or within fractures in bedrock. |
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| H |
Heave |
Upward movement. |
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Hot Mix Asphalt |
High quality, thoroughly controlled hot mixture of asphalt binder (cement) and well-graded, high quality aggregate, which can be compacted into a uniform dense mass. |
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Hot Mix Asphalt (HMA) Overlay |
One or more courses of HMA over an existing pavement. |
| J |
Joint Cracks |
Longitudinal separations along the seam between two paving lanes. |
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| L |
Lift |
A layer or course of paving material applied to a base or a previous layer. |
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Lime Treated Subgrade |
A subgrade preparation technique in which the subgrade soil and added lime are mechanically mixed and compacted to produce a higher modulus base material than the in-situ material. |
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Lithologic |
The characteristics which describe the composition and texture of soil and rock by observation. |
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| N |
Native Grade |
The naturally occurring ground surface. |
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Native Soil |
Naturally occurring on-site soil, sometimes referred to as natural soil. |
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| O |
Optimum Moisture Content |
The water content at which a soil can be compacted to a maximum dry unit weight by a given compactive effort. |
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| P |
Pavement Base |
The lower or underlying pavement course atop the subbase or subgrade and under the top or wearing course. |
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Pavement Structure |
The entire pavement system of selected material from subgrade to the surface. |
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Perched Water |
Groundwater usually of limited area maintained above a normal water elevation by the presence of and intervening relatively impervious continuous stratum. |
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| R |
Raveling |
The progressive separation of aggregate particles in a pavement from the edges inward.
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Reclaimed asphalt pavement (rap) |
Excavated asphalt pavement that has been pulverized, usually by milling, and is used like an aggregate in the recycling of asphalt pavements.
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Recycled Asphalt Mix |
A mixture produced after processing existing asphalt pavement material. The recycled mix may be produced by hot or cold mixing at a plant, or by procesing the materials cold and in-place.
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Reflection Cracks |
Cracks in asphalt overlays that reflect the crack pattern in the pavement structure below it.
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| S |
Scarify |
To mechanically loosen soil or break down existing soil structure. |
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Settlement |
Downward movement. |
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Skin Friction (Side Shear) |
The frictional resistance developed between soil and an element of the structure such as a drilled pier. |
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Soil (Earth) |
Sediments or other unconsolidated accumulations of solid particles produced by the physical and chemical disintegration of rocks, and which may or may not contain organic matter. |
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Strain |
The change in length per unit of length in a given direction. |
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Stress |
The force per unit area acting within a soil mass. |
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Strip |
To remove from the present location. |
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Subbase |
The course in the asphalt pavement structure immediately below the base course. If the subgrade soil has adequate support, it may serve as the subbase. |
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Subgrade |
The soil prepared and compacted to support a structure, slab or pavement system. |
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| U |
Upheaval |
The localized upward displacement of a pavement due to swelling of the subgrade or some portion of the pavement structure.
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