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Wet Dirt

Discussion in 'General Industry Questions' started by xcavate, Dec 21, 2008.

  1. xcavate

    xcavate Well-Known Member

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    Anyone know how to get some wet dirt to dry asap? I have about 400 cy of wet clay I need dry to grade a floor in a building with. The floor is structural so they want me to use all the garbage under the building but there is a million haunches in the slab that make grading the wet material ******.
     
  2. pushcat

    pushcat Well-Known Member

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    Best way to dry dirt is to keep it aerated, tough to do this time of year. You could add fly ash, lime or other additives, but by the time you figure in cost of materials, trucking, and actual working of the materials, you're better off just importing suitable material. I know, general contractors and owners can't seem to grasp that concept, but 400 yds is nothing.
     
  3. xcavate

    xcavate Well-Known Member

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    Contaminated Dirt

    Its contaminated material it cant leave the site. They are putting it all under the building. So If I was to add lime to it how much would it take? Its going to be a change order I just need to come up with a solution.
     
  4. Turbo21835

    Turbo21835 Senior Member

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    Whats the material consitency? That determines the amount needed. Its not an exact science to stabilize material, it is an art form. For that yardage, I would say 25 tons of portland will put you where you need to be. It may be over kill, but someone else is paying for you to learn.
     
  5. joispoi

    joispoi Senior Member

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    x2 on portland. You´ll have to mix it in as you go. If you have to bring in extra fill, use aggregate and mix it in. It will set like concrete after it´s been compacted.
     
  6. xcavate

    xcavate Well-Known Member

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    So just get some portland cement type 2 and mix it in. Can I mix it in the stockpile or right before I put it down. The material is sloopy but not soup. If I get portland delievered in bulk I think I would have to mix it asap before it got wet. Any help would be greatly appreciated.
     
  7. Turbo21835

    Turbo21835 Senior Member

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    What are you using for equipment? This does not sound like a stabilization job, rather a modification. Thats splitting hairs, the dividing line is based on % of material added. I assume you have a soils engineer for the project? If so, get with them. Base your amount a portland needed on your moisture content. Lime will work, but it is usually more costly than portland, and it has more handling downsides, IMO.

    Our normal process for small stabilization was as follows. Assuming you are getting the load of portland delivered in bulk, you will need a big roll of heavy plastic. Dig a small pit, sloped deeper on one end, this will help you with spreading later on. Put dirt on the edge of your plastic, leave a few areas on each side where air can escape. Have the tanker driver get his hose as far under the plastic as possible. Have him blow the load off with low pressure and as much volume as he can. This will reduce dust.

    We usually spread the wet material over the fill area. Then using a backhoe, or loader we would grab a bucket of portland and start spreading it thinly over the wet material. If it is extremely wet you start nearest the pile working your way across the fill. This will help give you somewhat solid ground to drive over. If its dry enough you can move across without getting stuck, then go all the way to the other side of your fill and spread in reverse. This seems to spread the material a little more evenly.

    Mixing the material in. This always depending on how many sq ft we had to do, how wet the material is, and how well we needed the material blended. Im going to take it this job is small. Your best bet, if you have enough room is corner the blade of a dozer and roll it into the clay. Then windrow from one side of the fill and back again, at least twice. This will help blend the material in. If you can get a rototiller on a small tractor this will work well also.

    Now here is where things are tricky. This is more art than science. Depending on how wet your clay actually is, you may need to add water. Sounds back asswards when youre trying to dry material. But the portland needs moisture to start working. If after blending your portland, the clay looks more like sand and is granular, you need more moisture. If it looks like a load of dry clay picked up with a self loading scraper, youre in good shape.

    Compact, and grade as normal. Remind your soils guy that the moisture level on his density gauge may be a little higher than it should be for the material and proctor, have him come back a few days later. Remember, portland will burn you, its not as bad as lime is though. You get some lime in your boots and sweat a little, you will have a real hot foot. Common way we tested our lime to see if we had a good hot batch, was to mix some lime with water in a plastic pop bottle, toss it away and watch it blow up. I would also say, be prepared to clean your equipment. It is a dusty job, and if your machines have any moisture on them, the cement will stick right away. A good washing will take care of this. Also, be prepared to replace air filters on your machines.
     
  8. AtlasRob

    AtlasRob Senior Member

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    bulk powder

    I agree 100% with the advise given

    :notworthy WOW! another lesson learnt. So simple yet so effective. :drinkup

    If you can get your hands on a tractor mounted tiller/rotovator you will have it sorted.
     
  9. catken

    catken Well-Known Member

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    fly ash

    use fly ash and will solve your problems
     
  10. Turbo21835

    Turbo21835 Senior Member

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    Flyash will help to an extent, but with it being winter, it takes a lot of fly ash. Top that off if you get a bunch of rain your going to start going back to what you started with real quick. Portland and lime are your best bet this time of year as they create their own heat and will burn off any frost in your soil.

    Forgot to add, be quick about digging your footings and any grade work your doing, portland stabilized clay can be some hard digging if you let it set up. On one project we were just doing the stabilization and compaction work. Another contractor had the fine grade work. They waited two days before bringing their grade crew out. With 90 deg temps the portland set up like right now. They couldnt even get the rippers in the ground. So we ended up milling the top of the runway so they could grade it.

    Hey AtlasRob, how much do you think I should have charged for that trick?

    Also, if your looking for someone to help you out, let me know.
     
  11. xcavate

    xcavate Well-Known Member

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    The material is in a pile now. We are taking from that pile and dumping it to a mini excavator that is doing all the shaping. There isnt more then 5x5 of flat ground in this building. I have a PC228 excavator and L120 loader plus 2 minis and a skid steer. Can I mix the portland in with the pile to dry it out then rehandle it and grade and compact it in place? I would use the excavator and loader to mix the portland into the pile.

    As I said before its all considered contaminated which it really isnt. The soil is a dark brown silt to fine sand. The stuff isnt so bad as it self levels but it needs to dry out about 10-15% so I can work it easier.

    How much is in a bulk truck of cement hold and about how much does it cost?
     
  12. Turbo21835

    Turbo21835 Senior Member

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    How many cubic yards is your pile? I dont see where if would be a problem to mix the portland right at the pile then spread and compact, as long as you use everything you mixed with portland in that shift. If memory serves me right we were getting tanker loads that weighed 25 tons. Not sure on price, but it was a lot cheaper than lime. Something you may consider is contacting a local redi mix, or maybe even a block supply company. Im willing to be the block guys may have something for you. Since I have seen masons use a small "silo" I watched them load it with from a super sack.
     
  13. xcavate

    xcavate Well-Known Member

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    I have about 400 cy left that I have to use and am doing about 1o0 cy a day. Does the portland change the consistancy of the soil right away or does it take a while?
     
  14. Turbo21835

    Turbo21835 Senior Member

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    It shouldnt take too long. I would say a 2000-4000 lbs of portland per 100 yards would get your pretty dry, pretty quick. Thats a lot of powder to add, and as the portland cement gets wet the chemical reaction that takes place will create a good amount of heat that will also help with drying. Your not really looking at a lot of material so im thinking if you can get portland cement from a masonry supplier in 2-3000lb super sacks is going to be most effective for this project.
     
  15. swampdog

    swampdog Senior Member

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    I've been following this thread with interest hoping to learn something. My first thought was that adding portland cement to the wet soil would result in a concrete like substance that could harden up much like concrete. You probably don't want that as that would interfere with proper compaction and other site preparation activities.

    But adding only 6,000 pounds of portland cement to 400 yards of material (about 1.2 million pounds) should not result in concrete. Using rough calculations, your silt/sand to cement mixture would be mixed in a ratio of about 200 to 1. To make concrete, a 5 to 1 or 4 to 1 mix is common. So I can't really see much risk of you ending up with a surface that can't be worked if you go with the 200 to 1 mix.

    Before spending a lot of money on portland cement, you might want buy one bag (40 kg in Canada) to mix a few test batches using different formulas. If it gives you the drying results that you want, you then can approach the larger job with confidence.
     
    Last edited: Dec 23, 2008
  16. Turbo21835

    Turbo21835 Senior Member

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    Thing to remember about hand mixing a "test" batch will provide a results that you may not be able to re create by mixing in volume and with a machine. Using an excavator and loader will not give you a thorough blend like a shovel will.

    As far as being too hard? You can place and compact portland stabilized soil just like any clay material. It will not be rock hard, but will be hard. Grade it as soon as it is placed and compacted. It will fully set in a few days depending on temps.
     
  17. Bob Horrell

    Bob Horrell Charter Member

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    I don't have a lot of experience with this problem, however, I had a job where I was grading a pad for a barn and had the wet clay problem. I added dry sand and worked it into the clay. It was easy to do, cheap, and left a well compacted and stable pad. For that job I used about 25% sand. I was using a 4X4 skiploader which could hardly travel on the clay without getting stuck when I started. I spread the sand on top of the clay and worked my way across the sand I spread to get further onto the job. Once the sand was spread on top of the clay (I could then drive on it without much problem), I ripped and cross ripped it mixing it in well and helping to dry it at the same time. I then finished and track rolled it to a very hard and stable surface.
    I know this probably won't work for this job but it might work for someone else in a similar situation to the one I was in. It really depends on how deep the moisture is in the clay, whether or not more moisture is introduced while working it etc.
     
  18. AtlasRob

    AtlasRob Senior Member

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    A trick like that is priceless if you've got a bulk load of powder you need to unload and have nowhere to store it.

    Have this one on me :drinkup ;)
     
  19. surfer-joe

    surfer-joe Senior Member

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    I've worked with a lot of soil cement and you have to compact and fine grade as soon as you can. Once it sets, you are done.
     
  20. AtlasRob

    AtlasRob Senior Member

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    I think the test batch mix is a good idea.
    I would suggest a bucket of muck with the L120 then add a bag of cement dust ( 25kg UK ) Swampdog says 40kg Canadian, shove the muck about with the L120, roll it, backblade it etc you know the score, then see what you get. Depending on how wet the muck is and how big your bags of dust are you might have to add another bag or even 2, but it will give you a good idea of quantities required IMHO.