Paving 101

Rose Paving / January 20, 2010

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Team applying an emulsion-based seal coat
Team applying an emulsion-based seal coat

Have you ever been confused by the terminology used in the paving industry? Let us help clear things up for you! Below are some of the terms commonly used in paving. Become familiar with these and you will have a better understanding the next time work is being done on YOUR parking lot.

Asphalt: The common name for “Bituminous Asphalt 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.

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.

Concrete: The common name for “Portland Cement Concrete Pavement.” A hard, compact building material formed when a mixture of cement, sand, gravel, and water dries.

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

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.

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.”

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

Reflective Cracking: Cracks in asphalt overlay pavement caused by cracks in the existing pavement “reflecting” up through the overlay. Specialized techniques and materials such as multi-membrane paving fabrics help reduce this problem.

Seal coating: 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.

Sub-grade: The soil prepared to support a structure or a pavement system. It is the foundation for the “pavement structure.”

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.

For a complete glossary of paving terms, visit our website and select “Paving Glossary” from the Education drop-down menu.