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Using a Pug mill to add moisture to Clay

Using a Pug mill to add moisture to Clay

(OP)
Hi all!

Currently considering unsing a pug mill to mix moisture into clay which is then used to form dam embankments.

Has anyone done anything similar? Common practice here is to mix it using an Excavator.

Please pass on your thoughts.

Thank you!

RE: Using a Pug mill to add moisture to Clay

You might plug your pug mill . . . the problem with this an excavator mixing - is the clay material being brought out in "lumps"? If so you would only be wetting the outside of the lump . . . nothing inside changing . . .

RE: Using a Pug mill to add moisture to Clay

(OP)
Thank you for your reply!

Clay is broken out into all sorts of sized lumps. Excavator mixing is slow and still requires grader to mix it in a confined area. WHat i would like is for it to come out workable like a pavement material to allow the grader to just grade and move out of the way.

Have you tried this before????

RE: Using a Pug mill to add moisture to Clay

pre-wetting a stockpile or borrow site using sprinklers or water trucks may be a better method. You need to allow enough time for the water to penetrate. Mixing should only be done to blend the material after it has been watered.

RE: Using a Pug mill to add moisture to Clay

An asphalt "reclaimer" can be used for this purpose, but will only work in 8 to 10 inch lifts...which is better for clay anyway. They can also be set up to inject moisture into the clay as the mixing occurs.

As cvg noted, allow time for moisture to move through the material before compaction.

RE: Using a Pug mill to add moisture to Clay

(OP)
Thanks everyone.

Not sure if the reclaimer would be appropriate as we are bulking it out using a excavator. What i would like is something to dump the clay into.

We are allowing the moisture to move into it, but mixing it using the excavator is slow and still leaving quite large clumps which the moisture is not penetrating.

The clay is being used for dam walls so the volumes are quite large and the working platform is only around 8m. Having the grader remixing and breaking down is like having an elephant in a room. No rome to haul or work around him.

Any other ideas would be greatly appriciated.

RE: Using a Pug mill to add moisture to Clay

if you have large dry clumps, than you need to wait longer for the moisture to penetrate. maybe try a disk to break it up and mix, but only after sufficient prewetting

RE: Using a Pug mill to add moisture to Clay

(OP)
Please define what a disk is? is there another name?

We also have alot of silica in the soil which is drying it out.

RE: Using a Pug mill to add moisture to Clay

I'm finding that our clay (weathered claystone) lumps are broken down quite well using multiple passes of a dozer track. This should make the lump size okay - but we do this on site where the material is spread out . . . can then add your moisture (you never said how much "low" the moisture is than what you wish to compact at) and let the soil condition . . . sprinklers and working area with dozer again. Can you not do this work on site - or does it have to be in the "conditioning yard" you have . . .?

RE: Using a Pug mill to add moisture to Clay

(OP)
its a mixture of a couple of things.

We are pulling the clay from a borrow pit but there isnt a huge ammount of area for mixing. I saw the pug mill as a means of reducing the ammount of plant and labour. If i could chisel it out with an excavator and dump it in a pug mill which produces 300t an hour of workable clay, i could create a very efficient process.

my biggest fear is clogging the pug, but the material is very dry and it not producing enough.

All of the above ideas work well, but im working on a tight budget. I would prefer less plant and man hours if possible.

Any ideas would be great.

RE: Using a Pug mill to add moisture to Clay

There was a machine made in the late 40's called a PulviMixer. I saw it used on several occasions. Could mix to at least 12 inches I think. Give a look at a large farm tractor hauling a PTO powered roto- tiller. I have one that I have used for Spring-time preparing a very large garden. Mine is only 5 feet wide on a 28 HP tractor, but I am sure there are those much larger. Can really do a mixing job to about like the asphalt reclaimer, but is hauled by a tractor so difficult slippery ground is no problem. Then you could load up the mix and use it elsewhere. Of course this also would work on a job where you add water, mix and then compact.

Try this link and you can see what I am talking about. http://www.landpride.com/product-search/rotary-til...

There likely are many other makes out there.

RE: Using a Pug mill to add moisture to Clay

OG...that's essentially what an asphalt reclaimer does.....it is a big roto-tiller.

RE: Using a Pug mill to add moisture to Clay

(OP)
Hi everyone.

All these ideas are helpfully and thank you for your responses.

What i would really like to do is less work on the top of the bank and more on the floor. Something that your could dump 3-4m3 in and out comes proccessed workable optimum clay.

RE: Using a Pug mill to add moisture to Clay

Is this a means and methodology question or a performance spec? I agree on potential use of an asphalt reclaimer, Bomag used to market theirs as a 'tiller, but I've typically only seen that on soils where we added lime to reduce the moisture & up strength. Wetting and disking is usually all we had to do to get moistures up (that or wait for the first rain). Why can't the contractor place the material in lifts and temper the soil into spec insitu? Nuclear density test, speedy moistures, ... would all give you testing feedback required.

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