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 a ...

pavements 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 mix ...

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 Fly ash, flue ash, coal ash, or pulverised fuel ash (in the UK) plurale tantum: coal combustion residuals (CCRs)is a coal combustion product that is composed of the particulates (fine particles of burned fuel) that are driven out of coal-fired ...

, or asphalt emulsion 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 surface. Since this method recycles the materials '' in situ'', there is no need to haul in

aggregate Aggregate or aggregates may refer to: Computing and mathematics * collection of objects that are bound together by a root entity, otherwise known as an aggregate root. The aggregate root guarantees the consistency of changes being made within the ...

or haul out old material for disposal. The vehicle movements are reduced and there is no need for detours since it can be done under traffic, making this process more convenient for local residents. FDR with cement saves money while preserving natural resources 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