Lime Stabilizing soils. (What is that white powder?)
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- Опубликовано: 24 июл 2018
- Lime modification/stabilization is typically used to dry or stabilize over-moist clay based subgrade soils to allow follow on work to proceed quicker. There is some experiential evidence that it actually improves "strength" of the subgrade although that has been hotly contested by some engineers. It is basically a Lime Kiln Dust (powdered cement is sometimes substituted if the soils contain too much sand, at a much greater cost.) that is thoroughly incorporated into the top 12-16 inches typically and then recompacted with a sheepsfoot roller, regraded and then smooth-rolled before subbase is installed.
This job took place mid July of 2018 on a school parking lot expansion project in West Lafayette, Indiana. 
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Our company rebuilt U.S. 61 through Tunica Mississippi in the 1990's and instead of blowing out the hydrated lime out of pneumatic tankers
Environmental Regulations due to the dust we had modified some water trucks with 8inch drop pipe bars. Brought in a contractor who was set up to mix the lime out of the pneumatic tankers and mix it with water to make a slurry the trucks would come on site and would dump the lime slurry on the roadbed in front of the mixers and grade crew. The lime in rural areas were blown out dry then water added during mixing.. that lime slurry would heat up in those tanks on the water trucks where you couldn't touch the tank with your bare hand.
This video is some high quality content for construction professionals. Thank you
Thank you! I was studying about this in class, and it was really neat to see it in action.
Wow! You sure have to go through alot of steps to get the expansion ready for pavement. Thank you for sharing
Interesting practice of using the blade rippers after lime was applied . And generally Terex compactor with skeleton wheels is used instead of sheep foot .
I thought a water truck + soil-stabilizer could be linked up via a heavy duty tow bar and water hose then used together simultaneously ? The recycler (which usually has the dual function of being able to discharge water, slurry, and other liquids) can inject water---being pumped from the truck---into the soil while also mixing in the lime. This would save a step in the process. Perhaps the project was small enough where hooking up the equipment would actually take more time ?
Thanks for watching! Yes, that can be done I'm sure, although none of the lime contractors in this area do it (that I have witnessed, anyway). I have actually seen it done on asphalt in-situ remediations where the emulsion truck is connected by hose and asphalt emulsion is injected into the cutting drum chamber to achieve what you're talking about. And also, yes, the length of this particular project was short enough that there wasn't room for any sort of train situation as you can probably tell by the machines weaving back and forth around each other.
We only hooked up water trucks to the mixers on jobs where we had room
AIRPORT AND ROADWAYS but, only where the haul distance from water supply was not too great.
Are you doing this for black soil stabilization?
Please provide how much lime required per square feet?
Can I do this surrounding of my house which was considered on black soil?
I have lot of questions to ask how to connect you?
Do needful
We were stabilizing clay fill dirt. It didn't need the extra treatment as it compacted to pretty well 100% before we added the cement. The process will harden up all manner of soils and help dry overly wet soils in the case of lime treatment.
Never saw lime plowed in with grader scarifiers or rippers have seen disc used and just the mixers used. Lime when used on Arkansas gumbo works great to just get it in a workable state but, it is a nasty operation
You dont want to do on really hot days cause the lime dust will react with the moisture on your skin in your nose and mouth DUST MASK ARE REQUIRED.... PORTLAND CEMENT NOT AS BAD BUT, CAN BE JUST AS BAD...
I'd say the reason they do the initial ripping in is to get slots for the lime or cement and water to penetrate the soil profile and start to mix with the water instead of having wet puddles of cement standing on the surface. We have enough sand content locally in the soil that the county won't accept lime stabilization as a credit to replace part of the crushed stone subbase section, but 10-14" of subgrade mixed with cement at 4-5% will generally earn an allowance of removing 6 of the 12" of stone - pursuant to a geotechnical review and pavement section design.
I don’t understand unmixed lime remaining next to the existing asphalt, must have very loose specifications and inspections.
At the time of design, apparently the soil had excess moisture and the engineer was worried about constructability and timeliness without major undercuts and import of crushed stone. The unmixed strip along the asphalt is the width of the housing outside the edge of the mixing drum plus enough space that you're not damaging the sidewalls of two $7000+ tires on that machine by rubbing them along the edge of the asphalt (which itself lay on unmodified subgrade with a gravel subbase.)
As I mentioned in the beginning of the video, the soils tech had tested the grade already at 100% compaction without the lime and it had been proofrolled prior to lime with a loaded tri-axle to the satisfaction of the geotechnical inspector. The engineer decided since the lime was in the contract, that they didn't want to remove it. Empirically speaking, the treatment was unwarranted, but we were directed to install it nonetheless. The specs were clearly written and there was continuous ongoing inspection by the design engineer firms representative and the independent geotechnical consultant.
@@manofinterests334 I understand what you are saying, but calcium oxide that hasnt reacted yet still runs the risk of reacting once it is covered up with the parking surface, causing damage to "finished" surface. I enjoy a nice open discord like this also.
@@pennworld Assuming you're concerned about shrink or swell of soils heaving or settling the surface product, here's some dry reading to alleviate your worries: www.sciencedirect.com/science/article/pii/S2215016120301485
From a practical standpoint though, my understanding is LKD is used directly in some asphalt mixes so from a product damage point of view it's not a contaminant. Next item of consideration is that around this area, asphalt is always installed over crushed limestone... which would be the next direct course installed on top of the lime dust, so hydration wouldn't affect that product. And in terms of hydration, the LKD was watered down thoroughly before mixing so the product that didn't get mixed would have mostly hydrated prior to installation of the stone subbase eliminating any worries that minimal shrink or swell that might affect the surface. The main thing you have to worry about (that we know of right now) with the unmixed LKD is getting it in your eyes, on sweaty skin or breathing it in... and that - is no bueno.
I think I got cancer just watching this video
Nah. Closer to lime poisoning... maybe silicosis? Cancer isn't going to get you today. At least not from this stuff...
Way to dry to compact properly
Mix is Way to dry, and that poor grader get it out of the lime that’s what the mixer is for ....
I was good with it until I saw the guy performing the nuke test with all of that equipment still running nearby. Good way to get killed. Happened to two techs in our company several years ago.
I was concerned about that as well, so I stood watch near him the entire time he was doing his work.
He was doing a compaction test
Dillon Moreland yes I know. Slang for ASTM 6938.
@@ybd3179 hydrated lime can burn your skin and would definitely not be good to get it in your eyes. This was cement powder, so you also have the phosphates and other nasties to worry about. Best to wear protective clothing and a mask if the dust is blowing around you.