Common Asphalt Terms
Aggregate: A hard mineral material, such as crushed stone, sand or gravel used in pavement applications alone or mixed with an asphalt binder.
Asphalt Emulsion: Asphalt binder and water that contains a small amount of an emulsifying agent.
Asphalt Millings: Fine particles of bitumen and inorganic material. Sized from dust to less than an inch. Produced by the mechanical grinding of bituminous surfaces. See Millings.
Asphalt Reclamation: Asphalt Reclamation, also known as Full Depth Reclamation (FDR), is a cost effective method of pavement rehabilitation. During FDR the full thickness of the asphalt surface and a portion of the underlying base are uniformly graded and pulverized to serve as the base for a new road. Additives such as cement or asphalt emulsion are often incorporated to increase strength. The result is a homogenous layer with improved structural capacity.
Base: The layer of material beneath the road surface. May be composed of stone, gravle, sand, aggregate, dirt, or asphalt.
Cold-In-Place Recycling (CIR): Removing and reusing the existing asphalt surface. Involves milling off the top 2 to 5 inches of the existing asphalt surface and mixing the crushed asphalt with an asphalt recycling agent, and placing it back down with a paver. CIR is typically performed using a train of equipment, including an emulsion tanker, milling machine, a paver, and rollers. See more
Cracks (Alligator Cracks):Interconnected cracks caused by excessive wear over an unstable subgrade.
FDR- Full Depth Reclamation. See Asphalt Reclamation.
Flotation: The ability to keep a tire as close to the soil surface as possible, without causing ruts, compaction or becoming stuck.
Hot Mix Asphalt (HMA): Hot mixture of asphalt binder and aggregate, which can be compacted into a uniform dense mass.
Lime: A calcium-containing inorganic mineral composed primarily of oxides, and hydroxide, usually calcium oxide and/ or calcium hydroxide.
Millings: Fine particles of bitumen and inorganic material. Sized from dust to less than an inch. Produced by the mechanical grinding of bituminous surfaces. See Asphalt Millings.
Permeal Friction Course: Open-graded bituminous mixture placed over an impervious base. See also PFC.
PFC: Permeal Friction Course: Open-graded bituminous mixture placed over an impervious base. See also Permeal Friction Course
Portland Cement: Cement that is manufactured from limestone and clay and that hardens under water
Ruts: Channeled depressions in asphalt pavement. Also called Channels.
Seal coat: A thin surface treatment used to improve and/or protect asphalt surface.
Segregation: The non-uniformity of an asphalt mixture caused by physical segregation or thermal segregation.
- Physical segregation: non-uniform distribution or separation of coarse and fine aggregate sizes throughout the mass.
- Thermal segregation: non-uniform temperature distribution throughout the mass of a mixture.
Soil Cement: A highly compacted mixture of soil/aggregate, cement, and water.
Soil Stabilization: Process of preparing a surface for new road construction.
Subgrade: Soil prepared to support a pavement structure.
Tractive Effort: Tractive force and rolling effort on the road surface.