New cobble/setts - Help/comments

[TheVictorianCobbleCo]

I'm new here so please forgive if I cock up protocol. I'm introducing a 110x110x50 cobble/sett into the UK ex South Africa, as a cheaper alternative to the hewn granite sett. As the size is more uniform a it can be coloured in charcoal or sandstone, I believe it has a future here. My hassle is with the mix. I've used 60kg 10mm ballast with 12.5kg cement and 150ml Admix, and the surface finish is sandy on removing them from my own recipe rubber moulds. The wet mix at a decent slump is like tacky baby poo, so I suspect low quality ballast/too much sand. Thers stacks more info to give, but as a starter, any comments/advice?

[lutonlagerlout]

i suspect you are right about poor quality ballast,probably to soft a sand in the ballast,also the cement would have an impact ,i know rugby cement gives a nice finish for concrete whereas castle always ends up loking a weak mix.
try experimenting with different ballasts or even make your own,but i'm sure that sharp aggregates are stronger than soft ones
just my opinion
tony

[TheVictorianCobbleCo]

Thanks Tony, that helps a lot. I mixed up a 2.2/2.6/1 combo of sharp sand, 10mm granite stone and Blue circle enhanced (white packet) cement yesterday pm and could notice the difference immediately. I cast them and will take them out the moulds today, and am hopeful of good results. Will post the results.
Billy

[TheVictorianCobbleCo]

With the revised mix the results are magic! I will now trial the cobbles on a busy section of driveway. Can I take this opportunity to say thanks for a brilliant site, I've learnt/confirmed more in the last 2 weeks than in the last 2 years. I'm also happy to supply cobbles free of charge for wider exposure.
Billy Carter-Smith