Sub base - Why won't my base compact

[Dan84]

Hi need some advice just got 14 tonne of mot to 1 and have borrowed a wacker plate from a neighbour it is a heavy duty wacker but is about 10 years old and upon starting compaction it seemed to be doing the job but after more than 20 passes of a small erea laid at a 120mm depth it is still loose and just by brushing my hand across it it completely breaks up I have used hired wackers before and the compaction is solid please can someone help shuerly this is not right but my neighbrough says it is fine the stone complys to the right standard need to know cuz another 14 tonne coming tomorrow am

[seanandruby]

maybe that bit has a lack of fines. It should be ok when you sand it up and wack it in.

[Dan84]

Thanks Sean just got in bin spreading hardcore all day had a hour wacking it looks a bit beter still a bit spongey I have used a geotextile under the mot so hopefully it will be ok I have got another 14 tonne tomorrow to build it up to the required level someone has said water will help with compaction is this right is 82kg ok weight or do I need heavier I here what you are saying about the mix of fines will try blinding with sand tomorrow when I get all the mot. thanks Danny

[GB_Groundworks]

dont use water on mot

if you have an area like sean said with no fines you get marbelling you need the fines to fill the voids and lock the big stones together,

i had to hand dig through an area of mot today, albeit on a big car park so would have been compacted with a big vibrating roller had to pick axe through it, it was that well adhered to itself

[Dan84]

Ok no water on mot it rained heavly last night will it need to dry before compaction can anyone advise me on whacker weight I know there is a table on main page about kg/sq meter an can not make sense of it

[Bob_A]

Usual answer is the biggest/heaviest you can get.
But you're gonna be limited to what your hire shop has and if you've got lots of awkward corners a bigger machine may be limited.
For what it's worth I have a Wacker VP1340 which is 74Kg. I think it's great but then again I've only used to do a couple of diy jobs.
http://eprotool.com/wacker-1340-plate-compactor-p-6859.html