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Concrete clinker for the shop floor?

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Curious if anyone has any experience with using concrete clinker as a shop floor.  Have access to rediculiously cheap copious quantities.  Seems like it wouldn't be bad, but wanting to see if I am missing something.  


Thinking if I prep,

Dig out 8-10"


Drop landscape cloth

Drop 2 inches at a time and compact

Should be decently stable enough and if/when I decide to top it, nothing new to do?

Can get oil coated at the same price and by oil coated it is sometime called blackrock.  What is used to mix with blacktop, but just oil coated at this point.  So could do a few layer of oil coated then top with dry?


Or do not dig, just border and drop on top?  





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Thanks,  I  can get it for about $200 for 14cubic yards delivered.  Seems a good material, just have not ever played with it myself to know how it would hold up. is extremely light weight.  

Plans keep expanding the more I think about it.  Plan on adding a 20' expansion of about 1800ft^2 which would take about 3-4 loads worth to make a driveway to the shop.  Then was thinking while I was at it, I could just get the floor done for a shop at the same time.  So cost is just a small factor.  Would hate to get 3-5 truckloads out here and find out I made a bad call.    Also trying not to waste time and effort and at least make useable steps along to the final idea that are not at cross purposes.  Can get just one at a time and have time to compact (assuming it compacts).  Cannot find any good data on use as is when it is literally created to be ground into concrete.  


Currently sittting on old farmland, so not sure how much I would need to get down to be stable with vehicle weight, so just a guess on the 8-10"  Nothing built here before the housing development.  

Slabs would be poured if/when I can find equipment.  

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I have no experience with it and don't know if it's even available here in the Ozarks. What I have available and have used is crushed limestone and it works well for me both in he shop and drives. Hope someone with experience with it will chime in. Frosty has a lot of experience in AK with the road dept. maybe he knows about that stuff and we have several geologists on the forum also.

I can't control the wind, all I can do is adjust my sail’s.
Semper Paratus


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I would think that it would perform like gravel made of softer rock in that IIRC cement clinker is fairly soft, softer than, say, limestone rock.  So, under heavy weight, e.g. a driveway, the individual chunks would break up into smaller pieces and would compact more.  Also, it appears that cement clinker is reactive with water and will become harder if exposed to moisture.  So, if you are using it outside exposure to rain would give you something more like limestone gravel.  Inside, it would probably harden eventually but would take longer.  

I'm not sure if I would like a gravel or gravel like floor in my shop.  I think it would be less comfortable than dirt or concrete to stand and walk on.

How much thickness you need is more an engineering question and dependent on what kind of soil you have and what kind of uses you contemplate.  For a shop floor where it only has you walking around on it I would guess that you wouldn't need more than a couple of inches.  Compacting is always good.  If you have a choice, I would get the finest size available and then wet it down to harden.  If you can get a crusher I'd think that pea size and smaller would give a flatter and more solid floor.  It may be that if you are using a vibrating compactor it will break up the chunks and give you smaller size particles.

I have seen power plant fly ash which I believe is similar to cement clinker used as sort of a poor man's concrete for dust suppresion on dirt roads.  It is put down dry and then a water truck sprays it down.

As to whether you need to dig out an area or just put it on top of the existing soil would be, IMO, a question of whether you have power excavating equipment available.  Digging out even 4-6" of dirt by hand is a very demanding project.  I've thought about having a concrete floor laid in my shop which is a dirt floored old horse barn and the only way I'd think about doing it is if I could hire a crew to dig out the dirt to the depth I'd need.

I'd ask around with local contractors, particularly those who do driveways, etc. and see if they have any experience with it and what their experience has been.  If there is a cement plant in your area you might call their marketing department and ask about uses for cement clinker.

Just to be a bit pedantic I am using the term "cement clinker" because it is an intermediate step in the production of cement which is added to sand and gravel to make concrete.

Good luck and let us know what you decide and if you go with it how it works out.


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Thanks, and yes cement clinker is the proper term, I had already hit send before it registered in my head.  

Thinking about the compacting and the moisture, have a thought in my head to spread in some gypsum and see if it doesn't comglomerate or become a concretion itself with the rain?  Not as stable as mixed concrete for sure, just trying to make the best use of the material I have access to.  


Definitly not digging by hand.  Either equipment rental, or making this a partial contractor project where I supply the material.  Just put up a fence with preparation for this expansion.  So lining up boxes where I can. 


Heard a few times that this might not be comfortable to walk on.  Could always top with crushed granite or something similar after the fact if needed.  No roof height set yet, so another inch or two would not throw a wrench in the works.  Also, no roof yet, so should be easy to work at this point. 


May be a bit before I pull the trigger.  Really cannot afford the time to pause for this right now, and this will be a lot of compacting at a minimum, even if i have it dug out.  Figure a week or two of compacting between loads.  Especially if I do a full shop on top of the driveway.  No size set yet, but that would make this at least 4000ft^2 times whatever depth.  


Plan on retiring here right now.  So not a rush, more of taking advantage of an opportunity.  Once the kids shifts to his next job the price goes with him.  Needing to get ducks in a row and be able to pull the trigger if life takes a turn. 

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Neat stuff I wasn't aware of. Cement clinker is a modern form of what was called the slaked lime used to  make cements. I believe maybe the difference between old slaked lime cement and Portland cement is cement clinker. There is a good starter read on cement clinker here. https://civiltoday.com/civil-engineering-materials/cement/108-what-is-cement-clinker-clinker-definition-composition-types-uses

The next step after crushing the clinker in a ball mill is to add fly ash and you have Portland cement. The old slaked lime cement was crushed limestone that was burned to red heat and cooled it would be added to sand, gravel in a vat and water added to the desired consistency It was strong and lasted well but was brittle and broke down over time. I don't recall if it was a Roman improvement but they started adding volcanic ash, maybe as fines to start but discovered the ash made concrete hard but not brittle AND salt resistant.

Modern cement uses fly ash instead of volcanic ash to the same effect.

Anyway, all that said, I don't see why cement clinker wouldn't make good flooring if compacted solidly, I don't know how thick or what measures to take per depth. Broken up well, partially crushing it and water it should set up like poor concrete, think desert hard pan hard. 

How hard is the ground you want to do this on?

Has it been disturbed or is it original ground?

Is it dry soil or is there natural moisture below the surface, if so how deep?

Is the soil old farm field soil?

When you say "landscape cloth" do you mean a Geotextile? Meant to separate OG from fill and act as a barrier to fines, silts and clays while allowing water free flow. This prevents ground water from washing fines out of fill materials or conversely prevents clays and silts from washing into fill material and. For lack of a better term lubricating it so it can either move under pressure and vibration or freeze and heave in winter.

Geotextiles are serious business we see a LOT in use and sometimes misuse here.

While I wait for more details I'll throw out a couple things. OG is original ground, Existing ground is what's there now and may be compacted fill or graded and compacted OG. Or whatever but is not original undisturbed ground. Make sense?

Following your above prep and plan. If your existing ground is hard at depth you can clinker fill it in thicker lifts. 2" lifts compacted with a plate compacter will leave pulverized layers between lifts, the clinker powders fairly easily and might make a pad that wants to separate along the seams. Even if the powder hardens like cement they will be weak zones making your fill like a layer cake instead of one compacted mass. This isn't hard to deal with once you realize it CAN happen. More later.

Use a plate compacter and when the plate starts clattering STOP! You'll know when it happens a good example is to run one briefly across asphalt pavement. Then take a garden rake to the compacted surface to rough it up some. This lets the next lift mix some with the compacted material so there is no "seam". No need to go nuts just lots of deepish scratches is good.

Rinse repeat to depth.

How thick depends on the existing ground you're building on. 

I don't know about wetting it as you compact, I don't know how fast it will set. This stuff is not clay or silt, it's basically raw cement so it will react with water chemically and set not dry. Not knowing anything about this stuff I didn't read in the article I linked above I have no idea how much water to add during compaction. Watering when compacting is a tricky thing under normal circumstances and I have no idea how much or little to use with cement clinker. In normal soil water is a lubricant that lets particles to move past each other easily so when compacted smaller particles are driven into the spaces between larger until it's as solid as desired.

Cement clinker on the other hand will react chemically with water forming a low grade cement with itself as the aggregate (particles) and set up into a reasonably solid mass. Cool but how wet? I expect it'll want to be wetter than a similar gravel but maybe not. Cement being naturally hydrophilic it WILL absorb moisture from the surrounding soil, morning dew, etc. until it stops reacting and setting up. 

I'd be skyballing ideas if I speculate further. I have two suggestions at this point. First, call around and find someone who uses the stuff, probably the guys you're buying it from. Second, use George's excellent suggestion and make a small test pad. Maybe 2" thick the size of the plate compacter plate and use them for pavers elsewhere say at the bottom of the pool steps, etc.

I'll do some more web searching and see what I can come up with.

On the practical side rent a garden tractor with a front loader bucket and a rototiller deck. Set the depth of the tiller and make passes until it's chewed up to depth and scoop it out with the loader bucket. A couple hundred dollars and do your 4,000 sq/ft in a couple hours, sans blisters and back ache. 

If you don't have room a walk behind rototiller will save you hours of pick work so all you need do is shovel it into a wheel barrow.

Frosty The Lucky.

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Lot to answer, forgive me if I miss it on the first round.  And feel free to correct any assumptions i've made.  I can pick up in anything quickly, but do not know anything beyong a few books worth in road building. Appreciate the expert help.  

Old farm land.  Been a housing development on 1+acre plots for 25 years. In wet times, can sink into the top few inches just by walking on the ground.  In dry times, land will get 2" cracks in it. figure being old used up farm land too was distrubed, but not too far down would be solid?  

And yes, was thinking Geotextile to help keep the Clinker from sinking in.  No frost heave as I am down in Texas.  

Need to dig a hole or two and see what the ground really does.   Never run a perc test or anything here yet.  Have dug a bit for the septic line (aerobic) sprinkler repairs, but not really thinking about the ground stability.  Will be digging in some post holes for some steel post for gates and fence. Would be a good opportunity to see what's there. 

I am getting it from the mine, they dig and have this beautiful rotating kiln about a football field long to expand it.  They don't really use it.  Just off in a truck to whoever does.  I need to find someone that actually works with it and see if they can provide any advice. some guys have dropped it as roadbase per his coworkers memory, but haven't actually seen anything done with it myself yet.  tempted to just fingmd someone who uses this with blacktop, and drop off a few loads to them to keep the costs down and have blacktop with clicnker dropped, at least for the driveway part.  

They could provide it clean, or sprayed with an oil.  The blacktop companies use the oil sprayed version to mix with blacktop as an aggragate as far as I can tell.   Cost it the same to me either way.  $25 per load to cover the paperwork, then whatever truck I need to get it delivered.  


Tempted to just spend the $25 for a pickup load and make a few actual tests as suggested.  If I cannot find some hard data on what to do, just might take that option.  Honestly don't know if I dumped it into a pile, that it wouldn't turn into a solid lump after the furst rain.  


Would need to buy a plate compactor, but would need that regardless.  Have some at HF on clearance for under $350.  No idea how long they would hold up though. 

Do have a walk behind reverse tine tiller, but that would be a lot of work, and agree a rental is likely the way to go for the full plot.  

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It sounds like you have soil with a heavy clay component and that where is a fair amount of expansion and shrinking depending on whether conditions are wet or dry.  Have there been any issues with shifting or cracking foundations in your area?  (I suspect not because that is usually the result of very expansive bentonite clay which is altered volcanic ash.  That is more common in the Rocky Mountain area than in Texas.)  I believe that means that you wouold need a thicker layer of anything, gravel, cement clinker, etc. to support a load than you would if you had sandy soil which is more solid and compacted when wet.

If it were me, I'd get the equivalent of a couple wheel barrow loads and lay out a few small test areas of a couple square feet each and then use different variables, depth, intentionally soaked, dry, etc. and see what happens.  I'd drive one tire of a vehicle across them to observe load bearing characteristics.  This is, of course, if you can't find anyone with experience with cement clinker which would give you more guidance as to its suitability than experimentation.

I still think that a call to the marketing department of the company manufacturing it would be worthwhile.  

"By hammer and hand all arts do stand."

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Saying around here "It is not a matter of if your foundation will shift, but when".  So far no issues in my exact area, but decent foundations, poured deep enough for the load, and bolted to keep it compresssed if that makes sense.

Yep, thinking about testing myself for sure.  I understand DOE, just not any good data to play with this option yet.  Completely off scrip use as far as i can see.  Which means it is one of two options. 

1. Typically too expensive or 

2. Just a bad idea.


If it is just #1 im good. 

Currently pouring down rain for hours, so put a kaibash on digging a trench to see soil layers and compaction.  Will dig out a few square feet a few feet down and see what the walls look like soon.  


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I'm aware that your climate is a LOT different than semi-arid Wyoming (Laramie gets about 11.53" in precipitation/year) because I have two brothers-in-law near Tyler, TX.

You might check with your local US Department of Agriculture office and look at the soil maps of your area and then look at the characteristics of that soil type.  Also, the local office of the Texas Department of Highways (or whatever the actual Texas title is) may have engineering data on your particular soil type.  A phone call to the local highway engineer may give you a lot of information about whether cement clinker is a good or bad idea.

Keep us informed about how it all goes.  I'm finding this interesting.


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Thanks, yes we average 40" a year.  

Will try to look up some numbers and make calls Monday.  Always happy to talk with experts, just hard to track down the right resources sometimes. Appreciate pointing in the right direction.  


Will definitly keep posted on status as this progresses.  


If dusty when dry seems odd.  What i held in my hand seemed really clean.  Maybe after compaction and drying again it changes?  

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Not a degree but a little experience makes the difference. No idea what Crockett means unless it's a location or maybe the business selling the fill or? "Fine sandy loam" is perfectly clear, fine means all particles will pass a 20 screen (sieve with 20 openings per inch and no, openings are NOT 1/20th of an inch. -4 (passing a 4 screen) is sand, -20 means it is fine sand and loam is living growing soil like a farm field or garden. Sandy loam is probably less than 15% sand but without a gradation that is speculation.

Did they actually say "slopes"? Without knowing for sure my conservative self would assume that soil becomes unstable over a 1% slope if wetted past it's plastic limit, beyond it's liquid limit nothing is stable on a slope. Plastic limit means enough moisture you can roll a little between your palms and it will form little worms. It's plastic sort of like modeling clay. Liquid limit means wet enough you can put a small ball in the palm of your hand and tap your wrist from below and it will slump from liquefaction. Those are field tests requiring no equipment, tables, etc. There are lab tests that determine really precise numbers for all aspects of soils mechanics.

Frosty The Lucky.

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In soil science the name of the soil, in this case, Crockett, is the name of the location where it was first described scientifically.  It is the same as with geologic formations, e.g. the Mesa Verde Sandstone, the Oglalla Formation, or what I am sitting on and get my well water from, the Casper Formation.  So, this soil type was first described near someplace named Crockett (not surprising in Texas).  The soil type will vary geographically.  Hence, in your area it is fine sandy loam.  A mile down the road it may be somewhat different, maybe coarse sandy loam.


PS  I just mentioned this to my wife, Madelynn, and she raised the issue that if the clinker breaks down under use and becomes dusty that the dust may pose an inhalation hazard.  This might not be a problem if it solidifies when moisture is added but it is probably an issue that needs to be addressed.  I'm less concerned about this material because it is made of carbonates than I would be with something like coal clinker which is mostly silicates which break up into very sharp particles which can result in silicosis ("miner's tuberulosis").


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Thanks, yes.  Experience is more important than a degree and is truly appreciated for the interpretation. 

Still trying to digest the website.  


Building appears to be very limited due to a 1.00 shrink/swell (maxxed out).  Attched a few pictures below, one of the header and one specifically for this rated area. 





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There is a lot there you can't really use if you aren't in the business. Worse if you don't have geo info for your specific location it could cause you more troubles than guessing.  

What is the depth of bedrock? Don't know right? Try driving what we'd call a probe rod basically a smooth pointed piece of steel rod till it stops hard. Ground rod is perfect and heck you're going to wire it anyway aren't you? Borrow a fence post driver, mark the rod in 12" increments and count the blows per foot. You will not be able to use it directly for foundation design but it will provide some good information as to what depth it starts to harden up. Or maybe more valuable where undisturbed soils start if its ever been plowed, filled, etc.

Frosty The Lucky.

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