"Andrew" wrote in message
o.uk...

I need a base for some large log stores. One solution is to place them on
440x220x100 concrete building blocks. This could be achieved fairly
quickly, and allows for straightforward relocation at a later date.

The site is disturbed ground - so this may not provide uniform support and
I can expect some settlement. However I can make adjustments at a later
date as and when the stores are empty.

Concrete blocks seem to come in 2 main types - dense and medium density.
Both types are available for a compression load of 70 N/mm2. The medium
density blocks weigh about 14.5kg as opposed to 18 kg for the dense blocks
but cost approximately 10% more.

I am willing to pay the extra premium on the medium density blocks in
return for the easier handling. But will the medium density blocks be more
fragile and liable to break in my application where the variable nature of
the ground support may give rise to shear stresses across the blocks?

Any comments appreciated.

Andrew

Another variable is their material.They come as basically concrete, and
basically fly ash. My experience is that the concrete variety last much
longer in damp (ie on the ground) conditions, whereas the fly ash ones
crumble away with frost damage. Both materials come in different bearing
abilities so the 3.5 / 7.0 / 14 Newton loading doesn't necessarily determine
their composition. Concrete one have a smoother finish with less pore and
are heavy.

Andrew