# compaction



## drake (Feb 18, 2012)

what do you think has better packing results or pounds per sq inch a 4 stroke jumping jack or a 1000 pound plate tamper and we are packing 3/4 crush fairly moist or wet ..... what has more pounds per sq in do u think


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## Moxley-Kidwell (Jan 28, 2011)

I would guess jumping jack. The problem I see is if it's too wet I think both are going to bring the water to the top and you will have nothing but jello. Just my guess, I'm sure others with more experience will chime in.


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## tgeb (Feb 9, 2006)

Too many variables to give an accurate answer. 
But M-K is also correct.


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## drake (Feb 18, 2012)

i no what happens it does turn to jello, im also wondering the specs on the jumping jack and the 1000 pound plate what are the pounds per sq inch what gives u a better pack in a larger are i have a 30ft ring 2 ft deep filling up


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## CrpntrFrk (Oct 25, 2008)

Sorry if I offend but you are a foreman of an excavating company and don't know the answer to this question?

Lots of variables as Tgeb said. 

Both will give you the desired results if used correctly. Either way you should do nothing over 8"-10" lifts. 

Your dirt should compact in your hand when squeezed and crumble apart using a bit of pressure. If the dirt leaves mud in your hand it is too wet.


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## drake (Feb 18, 2012)

Ur not offending cause i know what I'm doin all I'm asking is what is the pounds per sq Inch on the 1000 pound plate and on the jumping jack i just loping for specs on that


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## rino1494 (Jan 31, 2006)

What model compactor, how many sq. in. is the compaction plate area, what size hp. ????


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## green (May 9, 2007)

So...how interested are you in a complete answer to your question? If all you are looking for is a number, I'm sure you could find it on the manufacturer's website for whatever piece of equipment you're using.

However, you've received some very good advice already. As tgeb suggested, the numbers you are looking for probably don't have any practical meaning. The site conditions and the methods you use have far more bearing on effective compaction than anything else.

If you want to start getting a handle on the facts surrounding compaction specs, try reading this:

http://www.mbw.com/pdf/Word2Wise.pdf

If that seems too painful for you, here are a couple of important points, taken from the body of the document:

"Compaction equipment users have always wanted to know how hard a rammer or vibratory plate “hits”. To answer this question, interested parties look to manufacturer’s published information. Unfortunately, IMPACT FORCE, CENTRIFUGAL FORCE, TOTAL APPLIED FORCE, AMPLITUDE and STROKE, AREA OF COMPACTION, DEPTH OF COMPACTION, WEIGHT, and TRAVEL SPEED provide interested parties with information of far less value than generally assumed. Relevance is at issue. Promotion of unrealistic performance expectations is a problem. Some information is presented in a fashion that encourages the public to mistake data for something it does not represent. "

"We have not provided an answer to the question … “How hard does the compactor hit?” At some point, users have to be educated, told that they are asking the wrong, in fact, an irrelevant question, and informed that there are no shortcuts or substitutes for good soil compaction practice"

My personal opinion: Use the jumping jack...it'll be easier to get unstuck.


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## jmacd (Jul 14, 2009)

The testing will determine if you compacted correctly.
I use jumping jack for trench work and small areas that don't have to be perfectly flat. 
Small plate for small flat areas like sidewalks. 
Large reversible plate diesel tamper for any larger areas were I can fit the machine.

I also own a single drum ride on for parking lots etc. All of these have different applications and all work if used correctly.


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## CanDoExcavating (Feb 11, 2010)

Around here alot of folks use stanley hammers mounted on a backhoe but instead of having a Moil point it is replaced with a 2' x 2' pad. Mostly used for compacting trenches and around foundations


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## EAycock (Feb 19, 2012)

*Compaction*

Two items of information are needed to answer your question. (1) The area (length by width) of the striking surface and (2) the force applied by the equipment. 

For example, if the equipment delivers a force of 1000 pounds and has a 4-inch by 4-inch surface, the pressure applied to the soil would be 62.5 psi (pounds per square inch). (1000 lbs. divided by 16 square inches)

If the striking surface is 12 inches by 12 inches and has the same 1000 pound of striking force, the pressure to the soil would be about 6.9 psi. (1000 lbs. divided by 144 square inches)

To determine which method compacts the best, have soil compaction tests performed for each one. 

Also, soils need to be compacted in small lift thicknesses. Well-graded gravel can be compacted in 10-inch to 12-inch lifts where clay soils should be compacted in 6-inch lifts.

One final note, soil compacts best at its optimum moisture content. If the soil is overly moist or overly dry, maximum compaction cannot be achieved.


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## S.R.E. (Apr 8, 2010)

There are so many way's to compact soil. There is only one thing that really matters. 
Does it pass the compaction test?:thumbsup:

There are so many variables that need to be considered. There is not just one formula to achieve compaction.


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