Exposed aggregate

[rab1]

i know at my brothers work there not allowed to take anything that contains sugar near the prodution area as a can of coke spilt means binning a cube.

[Tony McC]

My father-in-law (long dead and I've since divorced his daughter) was a concrete wagon driver and it was standard practice for them to carry a 2lb (1kg) bag of sugar in the cab in case they got a breakdown. He reckoned 2lb was enough to keep an 8m³ mix unset for 24 hrs and so give them a chance to get the wagon towed back to the yard to discharge into their own waste pit and save the mixer drum.

He drove an old half-cab, which will date me, and anyone else who remembers them. His couldn't run-and-pour so if we were kerb-laying and he rolled up, there'd be a collective moaning from the lads because we knew the concrete would be discharged in 1m³-ish piles around 10m apart that would then have to be shovelled into place rather than being churned out as a continuous windrow bed or 'straight-to-the-back' haunching.

Didn't know Rugasol had been stoppped. I thought I'd seen it being used last summer, but maybe it was summat else.

[lutonlagerlout]

I wonder what the chemistry is behind the sugar and cement not mixing
apart from the old richard the third trick I have seen gangs sabotage other gang's sand with sugar, i just assumed it would attract wasps
hmm
LLL ???

[lutonlagerlout]

ps looked for rugasol and couldnt find it to buy anywhere
LLL

[Brucieboy]

Sugar affects the setting and hardening of concrete by delaying the hydration process - the chemical reaction between cement and water. Very simply, the sugar coats the particles of cement making if difficult for the water to do its job (the formation of tri-calcium aluminate and tri-calcium silicate in the early stages of hydration). As Tony says, mixer drivers have used bags of sugar or molasses to get them out of a fix - as long as the drum can still be rotated to mix it in.

Proprietary concrete set retarders are more engineered products such as hydroxycarboxylic acids.

[GB_Groundworks]

bruiceyboy is one of my favourite new members science and brew cabin

[lutonlagerlout]

I agree Giles
with bruce ,sean,jay, and 1 other whose name escapes me I feel we have a nap hand of concrete experts
all good
LLL

[Tony McC]

bruiceyboy is one of my favourite new members science and brew cabin

I've edited his excellent piece about fibres and hope to get it into the reinforcement page over the coming weekend, assuming I get everything else done. Today is the first day tis week that I've sat at my desk, and there's a HUGE backlog of work....

[Brucieboy]

Thanks for the comments fellas. Glad to be of help on this first class forum (along with the other members).

[TheRockConcreting]

How you getting on with this luton?

[lutonlagerlout]

found the cem1 and the aggregate
still not sure what 0/2 sand is?
obviously the weather has been against me so far
LLL

[TheRockConcreting]

still not sure what 0/2 sand is?

Its just washed soft sand, 5-7% clay/silt for concrete use. You can test this yourself with a glass coffee jar.