Full depth recycling or full depth reclamation (FDR) is a process that rebuilds worn out

asphalt Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term ...

pavements Pavement may refer to: * Pavement (architecture), an outdoor floor or superficial surface covering * Road surface, the durable surfacing of roads and walkways ** Asphalt concrete, a common form of road surface * Sidewalk or pavement, a walkway al ...

by recycling the existing roadway.

Processes

Old asphalt and base materials are pulverized using a specialized machine called a

reclaimer A reclaimer is a large machine used in bulk material handling applications. A reclaimer's function is to recover bulk material such as ores and cereals from a stockpile. A stacker is used to stack the material. Reclaimers are volumetric mach ...

. On top of the pulverized material, water is added to reach the optimal moisture content for compaction and then a variety of materials, such as dry

cement A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel ( aggregate) together. Cement mi ...

lime Lime commonly refers to: * Lime (fruit), a green citrus fruit * Lime (material), inorganic materials containing calcium, usually calcium oxide or calcium hydroxide * Lime (color), a color between yellow and green Lime may also refer to: Botany ...

, fly ash, or asphalt

emulsion An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Altho ...

are incorporated for stabilization. A reclaimer is used again to mix all the materials. After shaping and grading, the new base is compacted to produce a strong, durable base for either an asphalt or

concrete Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wid ...

surface. Since this method

recycle Recycling is the process of converting waste materials into new materials and objects. The recovery of energy from waste materials is often included in this concept. The recyclability of a material depends on its ability to reacquire the p ...

s the materials ''

in situ ''In situ'' (; often not italicized in English) is a Latin phrase that translates literally to "on site" or "in position." It can mean "locally", "on site", "on the premises", or "in place" to describe where an event takes place and is used in ...

'', there is no need to haul in aggregate or haul out old material for disposal. The

vehicle A vehicle (from la, vehiculum) is a machine that transports people or cargo. Vehicles include wagons, bicycles, motor vehicles (motorcycles, cars, trucks, buses, mobility scooters for disabled people), railed vehicles (trains, trams), ...

movements are reduced and there is no need for detours since it can be done under

traffic Traffic comprises pedestrians, vehicles, ridden or herded animals, trains, and other conveyances that use public ways (roads) for travel and transportation. Traffic laws govern and regulate traffic, while rules of the road include traffi ...

, making this process more convenient for local residents. FDR with cement saves money while preserving

natural resource Natural resources are resources that are drawn from nature and used with few modifications. This includes the sources of valued characteristics such as commercial and industrial use, aesthetic value, scientific interest and cultural value. ...

s by using existing materials and conserving virgin aggregates. The road performance is improved through better stabilization, building a stronger, low-maintenance road that will last for many years. With proper engineering and testing protocols the FDR process provides a design life-cycle of 30 years. FDR is a manufacturing process and not an installation. Other pavement materials, such as concrete, asphalt, or aggregate base go through a rigorous quality control program that meets a qualified standard prior to site delivery and contractor installation. The FDR process requires the same level of understanding and product controls during lab testing and field verification to meet long-term performance goals.

External links

Full depth recycling

The Asphalt Recycling and Reclaiming Association
* {{cite web , url=http://www.asphaltzipper.com/how_it_works/rr/full-depth-reclamation.php , title=Asphalt Zipper , author= , website=asphaltzipper.com Pavements Recycling

Processes

See also

External links