Terminology


Asphalt and Paving Terms

Aggregate

Stone or gravel that was crushed and screened to various sizes for use in concrete, asphalt or road surfaces used in concrete repairs and new concrete placements.

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 sub-grade or lower course of the pavement.

Asphalt

(Asphalt cement) A dark brown to black cementitious material in which the predominating 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.

Asphalt Emulsion Slurry Seal

A mixture of slow-setting emulsified asphalt, fine aggregate, and mineral filler with a slurry consistency.

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

Asphalt Pavement Structure

A pavement structure that is designed and constructed so that all courses above the sub grade are asphalt concrete.

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.

Backfill

Materials used in refilling a cut or other excavation, or the act of such refilling after the concrete foundation pour.

Base

The course or layer of materials in a roadway section on which the actual pavement is placed. It may be of different types of materials ranging from selected soils to crushed stone or gravel.

Base Course

The layer in the pavement system immediately below the binder and surface courses. it usually consists of crushed stone, although it may consist of crushed slag or other stabilized or un-stabilized material.

Binder Course

The layer in the pavement system immediately below the binder and surface courses. It usually consists of crushed stone, although it may consist of crushed slag or other stabilized or un-stabilized material.

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.

Cast-In-Place

Concrete placed and finished in its final location.

Cement

Finely powdered mixtures of inorganic compounds which when combined with water hardens with hydration and makes concrete as we know it.

Cement-Aggregate Ratio

The ratio, by weight or volume, of cement to aggregate in concrete.

Coal Tar

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

Cold Joint

A discontinuity produced when the concrete surface hardens before the next batch is placed against it.

Compaction

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

Concrete

A hard compact building material formed when a mixture of cement, sand, gravel, and water undergoes hydration.

Crack

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

Cracking

The process of contraction or the reflection of stress in the concrete pavement.

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

Expansive Potential

The potential of a soil to expand (increase in volume) due to absorption of moisture.

Exposed Aggregate

Surface texture where cement paste is washed away from concrete slab surface to expose durable chip-size aggregates for the riding surface.

Finish Grade

The final grade required by specifications for concrete placements.

Finished Grade

The final grade created as part of the project

Fly Ash

The finely divided residue resulting from the combustion of ground or powdered coal and which is transported from the fire box through the boiler by flu gasses; Used as mineral admixture in concrete mixtures.

Footing

A portion of the foundation of a structure that transmits loads directly to the soil.

Foundation

The lower part of a structure that transmits loads to the soil or bedrock.

Frost Depth

The depth at which the ground becomes frozen during the winter season.

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 sub grade or improved sub grade. A full-depth asphalt pavement is placed directly on the prepared sub grade.

Grade

The soil prepared to support a pavement structure or a pavement system. It is the foundation of the pavement structure.

Grade Beam

A foundation element or wall, typically constructed of reinforced concrete, used to span between other foundation elements such as drilled piers.

Green Concrete

Concrete that has set but not appreciably hardened.

Groundwater

Subsurface water found in the zone of saturation of soils or within fractures in bedrock.

Grout

A mixture of cementations material and water, with or without aggregate, proportioned to produce a pour able consistency without segregation of the constituents; also, a mixture of other composition but of similar consistency. See also Neat Cement Grout and Sand Grout, but not Concrete.

Hairline Cracking

Barely visible cracks in random pattern in an exposed concrete surface which do not extend to the full depth or thickness of the concrete, and which are due primarily to drying shrinkage.

Heave

Upward movement.

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.

Hot Mix Asphalt (HMA) Overlay

One or more courses of HMA over an existing pavement.

Hydration

The reaction of cement with water to form a chemical compound in concrete development.

Joint

A plane of weakness to control contraction cracking in concrete pavements. A joint can be initiated in plastic concrete or green concrete and shaped with later process.

Joint Cracks

Longitudinal separations along the seam between two paving lanes.

Lift

A layer or course of paving material applied to a base or a previous layer.

Lime Treated Sub grade

A sub grade preparation technique in which the sub grade soil and added lime are mechanically mixed and compacted to produce a higher modulus base material than the in-situ material.

Lithologic

The characteristics which describe the composition and texture of soil and rock by observation.

Moisture Barrier

A vapor barrier used under concrete to deter moisture vapor transmission migration.

Native Grade

The naturally occurring ground surface

Native Soil

Naturally occurring on-site soil, sometimes referred to as natural soil.

Pavement Base

he lower or underlying pavement course atop the sub base or sub grade and under the top or wearing course

Pavement Structure

The entire pavement system of selected material from sub grade to the surface.

Perched Water

Groundwater usually of limited area maintained above a normal water elevation by the presence of and intervening relatively impervious continuous stratum.

Portland Cement

A cement consisting predominantly of calcium silicates which reacts with water to form a hard mass, then transforming into a concrete or cementious product.

Proctor

A method developed by R.R. Proctor for determining the density/moisture relationship in soils. Important in concrete base construction. It is almost universally used to determine the maximum density of any soil that specifications may be properly prepared for field construction requirements.

PSI

1) Pounds per square inch; a measure of the compressive, tensile or flexural strength of concrete as determined by appropriate test. 2) In pavements, the Performance Serviceability Index.

Raveling

The progressive separation of aggregate particles in a pavement from the edges inward.

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.

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.

Reflection Cracks

Cracks in asphalt overlays that reflect the crack pattern in the pavement structure below it

Reinforced Concrete

Concrete containing adequate reinforcement (prestressed or not prestressed) and designed on the assumption that the two materials act together in resisting forces.

Scarify

To mechanically loosen soil or break down existing soil structure.

Settlement

Downward movement.

Skin Friction (Side Shear)

The frictional resistance developed between soil and an element of the structure such as a drilled pier.

Slump Test

Test used to determine concrete workability.

Soil

The loose surface material of the earth\’s crust, the base for most concrete construction.

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.

Strain

The change in length per unit of length in a given direction.

Stress

The force per unit area acting within a soil mass.

Sub-base

The layer of material placed to furnish strength to the base of a concrete or asphalt road.

Sub-grade

The surface produced by grading native earth, or cheap imported materials which serve as a base for more expensive paving. Necessary for concrete and asphalt finished road materials.

Sub base

The course in the asphalt pavement structure immediately below the base course. If the sub grade soil has adequate support, it may serve as the sub base.

Sub grade

The soil prepared and compacted to support a structure, slab or pavement system.

Upheaval

The localized upward displacement of a pavement due to swelling of the sub grade or some portion of the pavement structure.