Concrete over concrete thickness
- Thread starter SLM
- Start date
- Location
- Ardrossan Ayrshire
If it was mine I would fill any potholes then put a couple of inches of c40 on top. I have done a couple of eroded silage pit floors this way and the farmer was very happy with the job.
You MUST have it absolutely spotless or you will get issues, I think we used a pump mix to get smaller stone and hence an easier finish.
- Location
- Ardrossan Ayrshire
- Location
- South West
Following. Currently my main yard is cracking up and getting pitted. Half tempted to just pour over the top of it all but will cock the levels up too much so will need to dig it all out.
what sort of depth would people go for high traffic areas with lorry’s? 44t max but turning and reversing. I’d rather throw an extra inch at the job and never have to worry about it again but I don’t want to waste money.
what sort of depth would people go for high traffic areas with lorry’s? 44t max but turning and reversing. I’d rather throw an extra inch at the job and never have to worry about it again but I don’t want to waste money.
goldeneagle
Member
Would think 4 inches would be the minimum but depends on your appetite for risk. If sub base is solid may get away with thinner possibly 3. Old man did all our yard with 4" on about 12" subbase of gathered field stones in late 60s. It has held up ok even with artic lorries having to shunt quite a bit to get turned.
Cost it at 2" depth then 4" and work out whether the cost to replace is worth the saving if it goes wrong. Hows its laid and cured will affect strength in many cases (properly vibrated to get air out and covered for first 28 days to stop it drying out whilst curing).
Cost it at 2" depth then 4" and work out whether the cost to replace is worth the saving if it goes wrong. Hows its laid and cured will affect strength in many cases (properly vibrated to get air out and covered for first 28 days to stop it drying out whilst curing).
- Location
- South West
The subbase isn’t an issue I can put as much stone in as I can shake a stick at extremely cheaply, it’s currently on a 4” concrete thickness and has only lasted since the early 90’s. (With about 12” of base)
we have a high traffic volume so u suspect this is to blame and no drainage in the yard so water sits around for a while.
I’ve been measuring and costing it to go 5” with drainage installed with fibres in the concrete but I’m half tempted to put some mesh in too for the relative cost (in comparison to the above and the hassle factor of in potentially 30 years having to do it all again.
We’ve just put a new track in, mainly for lorries & big slurry tankers. Put down 8” concrete with mesh. No vehicles will be going on it for as close to 8 weeks as we can get.
Recently replaced concrete track that runs in front of our silage pits & thats 7”. An extra inch of concrete is cheap compared to redoing it in the future because you’ve skimped.
Recently replaced concrete track that runs in front of our silage pits & thats 7”. An extra inch of concrete is cheap compared to redoing it in the future because you’ve skimped.
- Location
- Ardrossan Ayrshire
Biggest reason for pad failure is traffic too soon. For artics etc you need to give it a month before use. If not it cracks underneath and these cracks work their way up through the slab over time. You do get high early strength concrete but it is basically just c45.
- Location
- South West
That’s going to be the issue and why I’m looking in to doing it in the summer. As this is the ‘main yard’ it’s unavoidable apart from going cross country. Hope for a dry summer and can just drive across a couple of fields to gain access from ‘the back’
I also run lorry’s so finding somewhere to park them up etc is going to be a task especially if it needs about a month!
Lakesdigger
Member
100% use mesh if you want it to last. Fibres are no replacement for mesh
- Location
- 200 miles N,NW of New York
We did half the yard infront of intake pit 6 years ago, I really don't know what concrete they used, but it was dug out on Friday night after 6 pm, levelled, sub base vibration rolled in, screeds set up by 1am, concrete poured at 6.30 Saturday morning, tempted down and left to dry,
Monday morning at 6am 44 tonne lorries were turning and screwing around to get on the in take pit, it gets around 16/18 lorries a day tipping ,
Not a sign of a crack or scuffled top surface,
What concrete would that be ?
Edit, there was steel mesh and fibre in it
- Location
- South West
To be fair I think there’s allot of ‘airing on the side of caution’ when it comes to concrete and weights.
I spoke to a guy I know in the concrete plant where I run some lorry’s in to and he said for the traffic and weight need to be atleast 250mm with mesh and fibres etc, needs to be vibrated and tamped out and needs to be covered and left to cure for a month etc.
I think the reality is there is a correct way to do it following manufacture spec and advice to the letter, and then there’s what the reality is you can get away with. Got to remember the manufacturers will add a percentage of time on for everything to make sure they don’t say yeah be fine after 48 hrs and it’s not and then there liable.
from abit of patch work we did we kept off it for 48 hrs and its not been an issue.
- Location
- Northumberland
Alternative to sheeting is to get a product you spray on with a knapsack sprayer. Did our farm road in the late `80s & its still fine
a 40 gallon drum did 400m x 3m approx
Google - concrete curing products
It’s over an existing slab of concrete so sub base can’t get much harder than that. It’s more to get a better finish and don’t want to grind down as a few bits of rebar now exposed
Did you get any before and after pictures?
suffolksmallholder
Member
- Location
- Suffolk
A well compacted base is one keystone. Laying over DPM another and an absolute minimum of 200mm C40 concrete with a maximum 4” slump using a proper slump cone are two more.
F-ing hard work but with the right machinery, workforce and a conscientious mixer wagon drivers things should go ok.
Seek more advice ofer reo and chairs.
SS
- Location
- Ardrossan Ayrshire
You couldn't do half the yard then the other half later?
- Location
- Ardrossan Ayrshire
goldeneagle
Member
You do get additives that will cut the cure time, like everything it all costs but if benefit is apparent its worthwhile.