The Brew Cabin

Posted: **Mon Oct 26, 2009 12:17 pm**

Hi,
I have an upcoming paving job where a client has pebbles in her rear garden and wants paving instead. There are a lot of pebbles and we would have to go through the house to take them out, something I'd be keen to avoid, can I use the pebbles in the sub base and if so is there anything I should add in case they move about on compaction? Would sharp sand do the job or would it fall between the pebbles leaving me with the same problem as before? Do you think I'd be better off laying concrete down using the pebbles in the ballast?
Many thanks

Posted: **Mon Oct 26, 2009 8:08 pm**

from a specification point of view, it would depend on the pebble sizes you have. to replicate a Type 2 subbase (generally sand & gravel) from single sizes you will need (approx):

35% of M Grade Concrete Sand
10% of 6mm
10% of 10mm
20% of 20mm
25% 40mm

although i have no experience of compacting sand & gravel GSB as we have so much limestone up north.

Posted: **Tue Nov 03, 2009 11:08 am**

With clean aggregate, such as pebbles, it usually best to incorporate them as the 'coarse aggregate' within a concrete. As rounded elements, they aren't really suitable as a sub-base.

The Brew Cabin

Pebble sub base