ASPHALT PAVING GLOSSARY

Aggregates: Usually various sized stones, crushed rock, gravel, etc. that make up approximately 92-96% of the asphalt mixture. (Asphalt Cement makes up the other 4-8 %.)

Asphalt: The common name for "Bituminous Concrete". It is also known as "flexible pavement." It is a mixture of aggregates and hot asphalt cement that when placed, compacted and subsequently cooled, becomes the familiar asphalt.

Asphalt Base: Asphalt mix where the largest stone used is no larger than 3/4 of an inch ( typically #57 gradation). Base mixes are usually laid over a stone base at a depth of 1 1/2 to 2 inches compacted.

Asphalt Binder: The asphalt layer between the base layer of rock or other aggregate and the driving surface layer. The asphalt binder layer is usually made up of coarser materials and is usually thicker than the surface layer. The binder layer can be used as either a first layer or a driving surface, but its use is actually fairly limited. The vast majority of jobs call for a stone base layer, an asphalt base layer, then a surface layer.

Asphalt Cement: A petroleum byproduct used to "glue" the pavement together. By volume, this material makes up about 4-8% of the pavement mixture. (Aggregates make up the other 92-96%).

Asphalt Concrete: See definition of "Asphalt" above.

Base: Generic term for material installed prior to asphalt paving. May be a crushed stone product or asphalt
product (see full-depth asphalt pavements). The base material provides the load bearing characteristics of the
finished pavement.  The correct type and amount of base material must be determined and specified prior to paving. Lack of adequate base material is a primary cause of pavement failures.

Base Failure: Base failures occur when the layer beneath the binder layer and driving surface can no longer
adequately support the weight of the structure or the traffic. Base failures can occur for a number of reasons,
including: ground water, excessive load counts (too much weight), and inadequate design. The failure can be
corrected by excavating the failed material and replacing it with bridging stone material.

BCBC:  BCBC is made by using 1 1/2 inch stone. It has a very pores finish which allows water to penetrate into the sub-base. BCBC is very strong and makes a great base, but should have a ID-2 wearing coarse applied as well.

Blacktop: Common "slang" term for asphalt. However this term should not be used in requesting any specifications or work as the term is widely used with various meanings in different areas. For example sometimes "blacktop" is used to refer to a penetration pavement or hot oil treatment (see fog seal).

Coal-Tar: A by-product of coke ovens in the steel production industry. Refined coal-tar has been used as a base for asphalt pavement sealers since 1938. It has become more expensive in recent years due to the shift in steel production to foreign countries.

Compaction: Compressing a given volume of material into a lesser volume. A compacted subgrade and base is
essential.

Concrete: A hard, compact building material formed when a mixture of cement, sand, gravel, and water dries.

Course, Asphalt Base: A foundation course consisting of mineral aggregate, bound together with asphalt material.

Course, Asphalt Surface: The top course of an asphalt pavement, sometimes called asphalt wearing course.

Cracking: A separation of the asphalt layer due to excessive loads (weights), heat, or age.

Deflection: Deviation of a pavement from profile under weight loads.

Drainage: A system of drains and pipes for carrying away surface water. An asphalt surface is sloped to maximize the removal of surface water for vehicular safety.

Emulsion: Mechanically produced combination of ingredients which do not normally mix. For example, asphalt
emulsions are made by a procedure which mechanically mills the warm asphalt into minute globules, dispersing them in water, and adding a small amount of an emulsifying agent

Fall: Slope. The degree to which a paved surface is angled to aid in the drainage of water.

Full-Depth Asphalt Pavement: The process of constructing an asphalt pavement structure using asphalt products for all components. The base material and surface courses are all made up of appropriately specified grades of hot-mix asphalt in contrast to conventional paving using crushed stone materials etc. There are numerous benefits to this method of construction.

Geotextiles: Geotextile is the technical name for fabric like materials used in the paving process. Geotextiles are manufactured for specific uses and performance characteristics. Some uses include stabilization of base material to prevent migration into sub-grades, retarding of reflective cracking in asphalt overlays, and serving as a moisture barrier between pavement layers.

Grade: Slope. The degree to which a paved surface is angled to aid in the drainage of water. The act of leveling or sloping the subgrade or base layer before paving.

Joints: An asphalt joint is the area where two different "pulls" of asphalt meet. This area is usually highly visible after the paving operation and is sometimes referred to as a "seam."

Lay down: The portion of the asphalt paving process where the hot asphalt is actually placed or "laid down" by the paving machine.

Mat, Asphalt: A term used to describe the fresh asphalt surface behind the paving machine. Most commonly used to refer to the asphalt during the lay down and compaction phase of construction.

Overlay: The practice of placing new asphalt over an existing asphalt or concrete surface. Also called resurfacing.

Sealcoating: Application of a sealant (usually coal-tar emulsion or asphalt emulsion type) to preserve, protect, and beautify asphalt pavements. Generally used on low traffic streets or off-street locations.

Slope: The degree to which a paved surface is angled to aid in the drainage of water.

Slurry Seal: A sealcoating process generally used on runways, streets, and roadways. In this process the coating is manufactured by the application equipment as it is being applied. A closely specified blend of graded asphalt emulsion, additives, and aggregate slurry seal is generally classified as Type I, II, or III depending on the size of aggregate used. A large aggregate slurry seal with additional polymers may also be referred to as micro surfacing. Used infrequently on parking areas due to the potential for tracking in hot weather.

Stone Base: The layer in the pavement system below the asphalt binder and driving surface. The base usually
consists of crushed stones of varying sizes and gradations.

Subgrade: The soil prepared to support a structure or a pavement system. It is the foundation for the "pavement structure."

Subgrade Failure: Subgrade failures occur when the prepared soil beneath the asphalt structure can no longer
adequately support the weight of the structure or the traffic. Subgrade failures can occur for a number of reasons, including: ground water, excessive load counts (too much weight), and inadequate design. The failure can be corrected by excavating the soft material from the affected area and replacing it with compacted soil or bridging stone material.

Superpave: Is short for "Superior Performing Asphalt Pavement". It is an asphalt design philosophy that uniquely designs roads, parking lots and other asphalt structures according to the environment. Variables such as weather, the amount of traffic, the type of traffic, etc. are taken into account.

Surface: Asphalt mix where the largest stone used is no larger than 1/8 an inch (typically #8 gradation). Surface mixes are usually laid at a minimum depth of 1inch compacted.

Tack Coat: Asphalt oil, usually emulsion type, applied to existing pavement during repairs or overlay paving to
create a bond between the old and new asphalt.

Tracking: The result of products or materials being "picked up" by car tires, shoes, shopping cart wheels, etc. and being carried from the pavement or "tracked" onto surfaces where the material is not desired.

Transverse Crack: A break in the asphalt pavement that is at a ninety degree angle to the direction of the roadway or the direction in which the asphalt was laid.

Transverse Joint: A joint in the asphalt pavement that is at a ninety degree angle to the direction of the roadway or the direction in which the asphalt was laid.

Joseph Di Palantino & Sons, Inc.
2028 Huntingdon Pike, Huntingdon Valley, PA 19006   

Office:  267-722-8205      mailto:info@jdpsinc.com     Fax:  267-722-8217

WWW.JOSEPHDIPALANTINOANDSONS.COM           HIC REGISTRATION #PA048974