Limestone dust

[slickboy]

Would it be ok to lay block paving on limestone dust or 'sinter' or would the fact that it's too limey mean it would effect permanent efflourescence in the blocks? I'm asking because a guy who supplies us with it for blinding hardcore says he supplies it to block paving lads for laying the pavers on instead of grit sand.

[Dave_L]

No idea but I know it goes damn hard!!!

[Tony McC]

No: it's not OK because it's not adequately free-draining. Limestone dust bind together (hence it's predominant use withing self-binding gravels) and as a consequence, its ability to drain is severely limited.

It's up to you to decide whether you wish to lower your standards to shave off a few pennies per metre and be one of the cowboy posse, or maintain your standards, working to proven best practice and so sleep easy at night knowing your clients are less likely to have you out explaining what's gone wrong and slagging you off to all and sundry.

[lutonlagerlout]

a mate of mine has just informed me that he has blinded his drive with " tarmac chippings" as the aggregate supplier did them for £10 a tonne
some people never learn

LLL

[slickboy]

Ok I see but would it cause efflourescence when mixed with cement and used as a mortar for bedding flags?

[Rich H]

Can't see how. It's the salts leaching out of the concrete/clay slabs/bricks/pavers that causes effluorescence.

[slickboy]

Thing is I've seen efflourescence in the shape of mortar dabs on the top of paving that has obviously been spot bedded so maybee it would!?!