How do i know when sub base is compact?

[perky416]

Hi guys.

How do i know when the sub base is compact?

My sub base is a layer of 20mm limestone with 10mm limestone on the top. It is for artificial grass.
I am running the compactor over it and it does seem to be compacting however it keeps pushing up areas to the side of the compactor which loosen up again. Please see the pics attached.
I have been over the entire area 4 times. It seems to be getting better slightly but the compactor keeps pushing areas up.
Thanks

 

[mikeey84]

Spray some water over it, that will help it lock together, but with just 10 and 20mm, you will never get a firm surface like you do with MOT1 or similar, as that has a calibrated mixture of 30mm to dust or similar.

If you are laying some sand before the grass, this will help (compacting sharp sand onto it will probably help it compact), but a compacted sub base is something you buy a proper product to make

 

[perky416]

Hi mikeey.

Thanks. I was thinking i wonder if its because theres no dust in the mixture. It was recommended to me by the artificial grass supplier to use the limestone instead of the MOT1 as we have drainage issues and dogs that will no doubt pee on the grass. I was told it wouldnt be as strong but would have superior drainage. It wont be sand over the top but 6mm to dust grano.

Is there any technique to using the wacker? I cant pull it backwards as it pulls all the stones up. I cant go up and down because of the arch of the turn at each end of the area. I initially went in circles going around the edge and working my way into the middle however it pushed stones to the middle and made a hill/mound sort of thing that i had to rake off

 

[mikeey84]

I'm no expert, but just did my drive last week. Id get it as flat as possible, water helps to stop it digging in, then lay the grano and compact it again (again, unless it's a bit damp, give it a good spray) that will help.

Your supplier was right about the drainage, but should have recommended mot type 3, which is suds compliant