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Posted: Thu Nov 04, 2010 6:02 pm
by fairview groundworks
I have laid a few farm entrances so concreting in general is OK but next job is on a slope steep enough that is 4 x4 only. I have to extend 20ft from existing.
Tamped finish to give more grip
do I trust the ready mix boys to delivery concrete with just the right slump otherwise I will have a dam at the bottom !! or do I get two mixers going and a team and set to.
Are there any ready mix tricks ? I have spoken to 2 companies and they can't guarentee anything
Size 20ft x 8ft x 6"
thanks
Posted: Thu Nov 04, 2010 6:34 pm
by lutonlagerlout
IIRC block paving is more suited to slopes over 12%
as you correctly worry ,concrete and gravity dont mix
if its for farm vehicles 80mm blocks on 30 mm grit sand and 200mm sub base should work
i have seen concrete belly on slopes and your heart goes into your mouth
LLL 
Posted: Thu Nov 04, 2010 7:51 pm
by GB_Groundworks
We have done concrete on steep slopes, decent concrete companies you can specify your slumps and mixes. We use cemex can't beat them, I wouldn't use volumetric as the mix tends to be poor, alternatively get your concrete and hold it till the right slump. Concrete sat in an idling dumper goes off really quickly,
Posted: Thu Nov 04, 2010 8:19 pm
by fairview groundworks
Thanks so far
I think i need an S1 slump. we also have cemex down here in sussex. Do you think S1 is right for a slope that is very steep?
would you pour it all in one go?
Posted: Thu Nov 04, 2010 8:31 pm
by GB_Groundworks
Cemex are global,
not in one section it out then extract timbers and fill voids, like building a concrete staircase.
Rough tamp or heavy brushed finish or add grit. Alternatively ronafix do high grip overlay products for concrete
Yeah s1 for slump.
Posted: Thu Nov 04, 2010 8:38 pm
by fairview groundworks
ok one last question, confidence is gaining all the time
so its a 6m length , i could make the "steps" every metre and if i understand correctly the staircase effect the concrte will be in one complete mass beneath the wooden formers.
the formers just hold it a bit while it sets
Posted: Thu Nov 04, 2010 8:57 pm
by rab1
yes is the short answer. just spend the time on the prep as you only get one go.
Posted: Thu Nov 04, 2010 8:58 pm
by GB_Groundworks
yeah, they are there to stop it slumping back down the slope only really needed on steep slopes
start at the bottom dont fill it all up at once, dont vibrate it or over tamp it till the consistency is right
and work from bottom to the top with finishing
Posted: Mon Dec 06, 2010 10:34 pm
by fairview groundworks
In case anyone was wondering... job done, superb
Before all the snow, just! Perfect mix and slump care of a helpful bloke at the batching plant from Bretts Concrete.
We started at the bottom as suggested, had rebar retaining " goalposts" every meter across the drive and didn't tamp too much. We add fibres just to make sure. It was really sticky and went in and then off a treat.
Customer still hasn't driven on it due to weather.
Thanks to all the advice.
Posted: Tue Dec 07, 2010 6:31 am
by Suggers
I was wondering - terrific - time to put up some photos David?