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View Full Version : The great compaction equipment debate


PSUhardscaper
06-13-2011, 10:35 PM
So where does one find the correct application for different forces of compaction equipment? IR's website says the BX-6 can compact 12" of aggregate, but Paver Pete tells me it's only good on top of the pavers... he recommends something that can compact 8" in one swoop. But, if it takes a skidsteer to lift it, how to you compact a patio with different levels? (rhetorical question).

I had a GC tell me today that he compacts 2A stone in 4-6" lifts with a BX-6. Just looking at the size of the thing, I suggested (he is a friend of mine) that he should 1) Use a larger compactor. 2)Or compact in 2" lifts.

He laughs and says that the compaction equipment's force is all relative to the size of the plate compared to the weight.... so a heavier compactor with a larger plate is the same as the smaller, lighter models....

the floor is open - it seems everyone has different view on this issue

DVS Hardscaper
06-14-2011, 06:35 AM
A heavier compactor is NOT the same as a smaller compactor! Is a small skid steer the same as a full size skid steer?

We use compactors of all sizes as warranted.

The world has been compacting pavements and the ground long before that gas engine was invented. So in other words, it's not that dramatic, unless you really wanna get done fast.

There is nothing wrong with a small compactor doing 2-inch lifts.




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TomG
06-14-2011, 10:43 PM
The GC that told you that is 100% incorrect. As DVS said a small compactor is not the same as a big compactor. Centrifugal force is what matters... We own 3 different sizes of compactors. Wacker 1550, with 3,375lb centrifugal force, Wacker BPU 3050A, with 5,625lb centrifugal force and Weber CR8 with 16,250lbs centrifugal force.

Generally this is how our three sizes of compactors are used... The 1550 is primarily used to compact the pavers in, but we also use it to compact lifts of no more than 2". The 3050A is used on small patios and walk ways and compacts lifts of no more than 5". The CR8 is used on big patios, driveways, all permeable jobs, and some walk ways. It compacts in lifts of no more than 10".

As DVS said there is nothing wrong with doing 2" lifts with the small compactor. I have done driveways long long ago with using a small compactor and 2" lifts and it has held up fine. But in our business time and efficiency is money so when we can lay out a full 6"-8" of gravel for a walk and compact it once instead of 3-4 times that saves ALOT of $$$$. Big compactors are big money but a bigger compactor is one of the few tools that instantly saves you money.

mxridernorth
06-16-2011, 01:48 AM
Well technically it's the stress (force/unit area) so the contractor would have been correct if he had done the math. So as Tom noted, take the centrifugal force and divide by the plate area and you will see that compaction pressures applied by the bigger machines are far greater than the smaller machines.

PatriotLandscape
06-16-2011, 02:58 PM
But there are larger asphalt rollers that may look like they do the job but put out a very low impact compared to size
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mxridernorth
06-16-2011, 03:36 PM
Once again, it comes down to the area over which the force is applied. Larger roller = more area = less pressure (stress) to make the asphalt yield.

SVA_Concrete
06-16-2011, 05:44 PM
Remember static vs dynamic is a factor in compaction.


do you step on the soft dirt or do you jump many times at a fast pace on the dirt.

PSUhardscaper
06-26-2011, 09:01 AM
A 'veteran' contractor in my area told me yesterday that the best way to handle having the correct compaction equipment is to have both an upright jumping jack, and a smaller plate like the 1550 or the IR BX-6. He compacts the subsoil, as well as 4-6" lifts with the upright. THe only thing he uses for small plate for is the last 1-2" lift (for leveling) and also to compact pavers once they are laid. Does this combo sound like the best way to spend 2k? We are getting into more hardscape projects and I'm tired of renting. I know it will be 2+ seasons until I can make that money back, but I've got to start somewhere - but I have heard 10 different opinions on what I need to do patios, walkways, and SRWs. Any advice would be helpful - I don't want to spend a lot of money and realize later I made a mistake. Thanks

DVS Hardscaper
06-26-2011, 02:32 PM
I do not own a jumping up and down style compactor.

They're more for trenches. (according to my brother in law who's a geo-technical engineer, and I agree with him)

In the last 5 years, we have probably needed/rented a jumping up and down style compactor maybe 3 times.

If I ever come across a nice used one for sale, I would consider buying it. Otherwise, it's not even on the wish list.





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PSUhardscaper
06-26-2011, 02:56 PM
I think my 'veteran's' point was that you can get more centrifugal force with the jumping jack - so use it for 90% and save the little plate compactor for leveling and on top of pavers. It makes sense - I'm just not sure yet if I should be buying his recommended setup or the BX8, which should be able to do 3" lifts.

DVS- are you using that Harbor Freight beauty as your sole means of compaction?

DVS Hardscaper
06-26-2011, 03:08 PM
a jumping jack is intended for closed areas, such as trenches, where it as sides that retain the material being compacted from springing out all over the place.


whats a "harbour freight beauty"? never heard of that...

PSUhardscaper
06-26-2011, 03:13 PM
My mistake - looking again it was SVA who posted this pic. So what would you recommend? Owning 1 plate compactor or two machines (I am working on a 2k budget for this stuff). Thanks

DVS Hardscaper
06-26-2011, 03:31 PM
You may get mixed opinions.

I have a simple view on business purchasing. Especially with a 2k budget. Buy what you need the most / what you will use the most.

Patio installation and r-wall construction call for a plate compactor more than a jumping up and down style compactor. Like I said - in 5 years we've used a jumping tamper 3 times. I mentioned r-walls. We use a plate compactor to compact within 3 feet from the block, and a trench roller for the remainder.

If you're installing water and sewer lines, or buring alotta 4-inch pvc - then you'll need a jumping tamper.


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PSUhardscaper
06-26-2011, 03:45 PM
what's the CF on your plate compactor and how big of lifts do you do on a compacted subgrade?

SVA_Concrete
06-26-2011, 08:19 PM
yes that harbor freight special is one of ours. works fine for most of the work we do, and god forbid I mention we do 4 inch lifts -- and yes we still achieve 98% proctor.

we rent larger compactors on occasion -- generally for larger jobs.

more important than the size of the compactor is the knowledge of how to compact materials...

PSUhardscaper
06-26-2011, 10:13 PM
yes that harbor freight special is one of ours. works fine for most of the work we do, and god forbid I mention we do 4 inch lifts -- and yes we still achieve 98% proctor.

we rent larger compactors on occasion -- generally for larger jobs.

more important than the size of the compactor is the knowledge of how to compact materials...

Please elaborate on this knowledge or point me in the direction of where to read up on this.

SVA_Concrete
06-27-2011, 05:51 PM
Please elaborate on this knowledge or point me in the direction of where to read up on this.


JLC field guide (foundation section), Moving The Earth (McGraw Hill), www.bomag.com, ICPI Tech Spec 3

Know your material Cohesive or non cohesive (clay or sand/gravel)
Know the Proper Use of your Equipment (vibratory tamp does nothing in cohesive soil)
and Know when to use Water and when to be Patient. (too much water produces poor results, too little water produces poor results)