Brush and steel finish - rough timings - Help needed for second time pourer

[djaychela]

Hi Chaps

Last time (about 18 months ago) you guys were hugely helpful when I had an issue with a concrete (C30) base I had poured - had a surface of about 6mm laitence on it which I needed to remove mechanically, and ended up with a good job (albeit with a day's extra work).

So, I'm after a bit of advice for my second job in the back garden.

I'm doing another slab, it's 6.5m x 2.5m. I've got a good sub-base ready, got a DPM, steel fabric to go in place and the right plastic chairs for the fabric to sit on - I'm confident it will be OK in that respect.

Last time out, I did the pour at about 4pm, which was (in hindsight) a mistake, as it went off overnight, and from what I was told at the time I should have left it a few hours for the laitence to drain away before tamping and attempting to surface it - I ended up with a weak top of mostly cement and water which underneath was OK, but I had to remove it with a tool.

This time, what I'd like to achieve is a brush and steel finish - this slab will be outside (between two garages) so I'd like to get the finish right first time.

I know that there's a lot of experience needed in terms of knowing when it's the right time to start working with the tools, but if anyone could give me a rough timeline of when they would expect to be doing certain processes, that would be great. The concrete will be arriving at 10am on Thursday, so if you'd usually not expect to be applying a finish until 4pm (say) then anything you guys can tell me would be really useful - last time out you were all really helpful and it made the difference between it being a nightmare and all being OK.

Thanks

Darren

[msh paving]

10 am is to late, you want in in at 8am give you 2 more hours to set it off, +3c and rising to pour concrete, this time off year it will go off slow, dont get it too wet, what trowels and float have you got? you need a narrow stiff brush to finish with,dont get on the concrete too wet,but if there is a wind blowing down it can go off quick MSH

[lutonlagerlout]

^^ as MSH says 5-6 hrs after laying for finishing this time of year,need the concrete at 8
LLL

[GB_Groundworks]

There is no timeline it's to dependent on mix weather slump etc

I assume you'll be using a dpm under your slab to stop grout loss and weakening of the slab, and a c35 mix? What thickness?

Brushed is lot more forgiving than a proper troweled finish

Have you got access to a side so you can trowel and brush in correct direction and are you hiring a Fresno trowel with brush or just using a yard brush?

We have brushes mounted on magnesium bull floats for quick finish to yards etc or mounted to steel trowels for finer brushed finishes

Our process would be lay, roller tamp, magnesium float then when at correct point brush then trowel edges and arris the leading edge etc you want to avoid any exposed 90 degree corners on slabs