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  • 1.  Corduroy Roads - Any Recent Uses?

    Posted 01-03-2019 09:58 AM
    Edited by Tirza Austin 01-03-2019 11:47 AM
    Is anyone aware of a recent use (last 50 years or so) of the Corduroy Road principle used on a modern topped road?  I have a fairly high traffic 2-lane asphalt road located in a rather saturated area.  It's in poor condition and construction equipment has proceeded to rut it out further as the base stays so wet.  In discussion, a corduroy road was suggested, but I only find references of application from more than 50 years ago (some of which did include stone & asphalt).   Thoughts?

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    "Corduroy road" on Revolvy.com
    Corduroy road Corduroy road In war, corduroy roads are often used as an emergency measure where poor quality roads have been damaged by the large numbers of vehicles or troops that have passed over them. Seen here are Germans in Yugoslavia in 1944.
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    Maria Price P.E., M.ASCE
    Engineering Manager
    City of Chattanooga
    Chattanooga TN

  • 2.  RE: Corduroy Roads - Any Recent Uses?

    Posted 01-04-2019 08:07 AM
    Edited by Tirza Austin 01-04-2019 08:07 AM
    ​The City of Waterloo dug up the remains of a Corduroy Road under a municipal arterial roadway during the construction of an LRT (See attached newspaper article).  I also recently came upon a low volume road where corduroy was used (see photo).  This is much more recent and certainly in the past 50 years.  We tested the road both corduroy and conventional with an FWD and got some interesting numbers.  While the deflection was about 3x the conventional, it was performing well.  Only issue was that some of the wood was near the surface and it needed some more granular on top. 

    David Hein P.Eng, M.ASCE
    Prinicpal Engineer,
    Applied Research Associates, Incl.
    Toronto ON
    (416) 621-9555

  • 3.  RE: Corduroy Roads - Any Recent Uses?

    Posted 01-04-2019 08:08 AM
    Edited by Tirza Austin 01-04-2019 08:08 AM
    Since the advent of geosyntetic fabrics, such as geotextiles and geogrids, use of logs for soil reinforcement has virtually disappeared. Less than 10 years ago I recommended it for an embankment on very soft, swampy soil, using the cut down swamp trees as reinforcement along the border of the embankment. In spite of the careless construction, with logs randomly placed, not orthogonally to the border and tied together as should have been done, only about 20% of the 3-m high, 500-m long reinforced slope failed, proving that somehow the reinforcement worked. But I doubt that even in such cases where logs are available, it is a more economical solution than the geosyntetic one, due to the intense handwork required.

    Eduardo Do Val P.E., Ing., M.ASCE
    Do Val Engenharia Consultiva
    Sao Paulo
    55 11 38133443

  • 4.  RE: Corduroy Roads - Any Recent Uses?

    Posted 01-04-2019 09:47 AM
    Edited by Tirza Austin 01-04-2019 09:46 AM
    ​A more modern approach would be to use geotextile to do this.  If one doesn't firm things up appropriately, use a second layer after you roll the first layer of aggregate above the first layer of geotextile.  You would most certainly be able to vibratory compact over the second layer of geotextile gravel fill.

    Brent Bubar P.E., M.ASCE
    Region Engineer
    Maine Dept Of Transportation
    Presque Isle ME

  • 5.  RE: Corduroy Roads - Any Recent Uses?

    Posted 01-04-2019 11:52 AM
    Edited by Tirza Austin 01-04-2019 11:51 AM
    I used the corduroy ​technique about 30 years ago on a farm to market road on the east side of the Andes in Ecuador.  We were working in volcanic soils that had insitu moisture contents in excess of 100%.  We used split mahogany logs (predominant tree in the region) which spanned the entire roadway and covered them with about 6 inches of river run gravel.  While the method was effective for the limited traffic the road received it was labor intensive and I do not know how long the timber would survive the rain forest environment.  I haven't been back since the construction in 1987, but google maps shows the road to still be there.  I would think corduroy would be cost prohibitive in the US and you would likely be using pine or some other soft specie for logs and the life of the road would not be long.  A better and more modern alternative is to use a heavy geotextile separator/reinforcement fabric under the base to reduce the pumping action.  You may need a geogrid/textile combination.  FHWA, NHI and the Asphalt Institute all have design guides as do most of the major geosynthetics manufacturers.

    Norman Dennis Ph.D., P.E., D.GE, F.ASCE
    Univ of Arkansas
    Fayetteville AR

  • 6.  RE: Corduroy Roads - Any Recent Uses?

    Posted 02-13-2019 10:24 AM
    Edited by Tirza Austin 02-13-2019 10:23 AM
    I have used the Tensar geogrid (Triax 140/160) extensively underneath 8 inches of flexbase over utility trenches which have not been properly compacted.  It is generally impractical to recompact very deep utility trenches underneath pavement in new sub-divisions.  In another case where a pavement had been constructed over a "filled in" creek (Mother nature remembered where the water ran), I had to use a geogrid/textile combination due to pumping action.

    James Anderson, MASCE
    Anderson Consulting
    North Richland Hills, TX

  • 7.  RE: Corduroy Roads - Any Recent Uses?

    Posted 02-14-2019 08:09 AM
    Edited by Tirza Austin 02-14-2019 08:08 AM
    For backfilling narrow deep utility trenches under a pavement, why not use CLSM (controlled low strength material)?

    Joram Amir Ph.D. CE D.GE. F.ASCE
    Amir Geotechnical Engineering Ltd.

  • 8.  RE: Corduroy Roads - Any Recent Uses?

    Posted 02-17-2019 09:11 PM
    Edited by Tirza Austin 02-17-2019 09:11 PM
    The use of Controlled Low Strength material would be ideal for backfilling of narrow utility trenches under pavement.  When used with high volumes of air, they are self compacting and self leveling.  Unfortunately they tend to be very expensive and then there is the haul-off of the excavated material.  My use of the Tensar geogrid/flexbase combination was primarily remedial in nature.  Trenches deeper than 15 feet, even if compacted at 95-100%, unlikely given trench safety standards, and perhaps "chimney" service connections, will settle several inches during the build-out phase of subdivision construction when pavements are subjected to their heaviest loads.

    James Anderson, MASCE
    Anderson Consulting
    North Richland Hills, TX

  • 9.  RE: Corduroy Roads - Any Recent Uses?

    Posted 01-04-2019 02:56 PM
    Edited by Tirza Austin 01-04-2019 02:56 PM
    Have you looked into Tensar Geogrid? I attended a seminar and they claim to have success on marshy soils. No doubt other factors will be involved.

    Akshaykumar Patel P.E., M.ASCE
    Round Lake IL
    (847) 223-8879

  • 10.  RE: Corduroy Roads - Any Recent Uses?

    Posted 02-14-2019 12:08 PM
    Edited by Tirza Austin 02-14-2019 12:08 PM
    Geogrids are good alternatives for filling over pumping sub-grades to get you above the failing area and to be able to get compaction on subsequent lifts if you have enough depth.

    However, you should try to determine and eliminate the excess water under the pavement section.  This can be done with cross drains and edge drains, which drain to ditches on the sides of the road.  Improper drainage is a major cause of failing roads and should be the first thing looked at.

    David Bradeson PE,MASCE