Full Depth Reclamation (FDR) is Used for Road Rebuilding Project for the First Time in Whatcom County

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Full Depth Reclamation (FDR) enables creating a stronger and wider road base and surface with minimal disruption of the project area while fully utilizing existing site materials. This eliminates the need to haul out and dispose of old materials as well as the cost to purchase and and disruption of hauling in replacement material.

Land Development Engineering

This process avoids tearing up the road, as well as loading and hauling away the old asphalt. The existing pavement is 100% recycled.

The principal engineers at Land Development Engineering and Surveying of Ferndale, Washington have proposed the use of Full Depth Reclamation and Cemented Treated base for the reconstruction of a section of Church Road, located in Ferndale, Washington. This process has not been used before on a public road project in Whatcom County.

The affected section of road is located directly South of the Ferndale Fire Station. This section does not provide proper sight distance as originally graded; as a result, the road has to be lowered. The conventional method is to excavate the existing pavement and gravel, cut the road to sub-grade and import 14" of gravel ballast, 2" of crushed rock, and place 4" of asphalt. The existing underlying gravel does not meet the ballast specifications and needs to be exported, adding to the cost of the project.

By utilizing FDR, the project will only need to pulverize existing pavement structure in-place and mix it with a certain amount of underlying base material to form an upgraded base. According to a principal at Land Development Engineering and Surveying, Ramon Llanos, "This process avoids tearing up the road, as well as loading and hauling away the old asphalt. The existing pavement is 100% recycled." In addition to the FDR, the project will add stabilization agents to make the roadway stronger.

Under the project proposal, the old asphalt will be milled and stockpiled on -site. The road will then be re-graded to the desired elevation using the existing gravel. The asphalt millings and powder cement are spread over the road surface. A CMI 650 reclaimer stabilizer machine will mix the gravel, asphalt millings, cement powder and underlying native materials. Then water will be added to the road, resulting in a cement treated base. This will result in a road base of equal or better quality and strength than 14" of gravel ballast.

Ramon Llanos is a principal at Land Development Engineering and Surveying (http://www.ldesinc.com). A Professional Engineer, Llanos is licensed in the State of Washington and has a Masters degree in Engineering from the University of British Columbia. In the early 1990's, he was involved in several road projects in British Columbia including one in 1991 which utilized Full Depth Reclamation (FDR) for the first time in British Columbia.


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