• Hello From Descent

    The publication date for issue 289 is the 10th of December, meaning subscribers should receive their copies during the week leading up to that date. It is also available from caving suppliers such as Inglesport and Starless River, or from our new website

    New Descent board here:

Non Caving Help

ANN

New member
Does anyone know of any Imprinted Concrete Pavers or anyone that could give me an Independent  Report on the cause of a crack on my drive.  We suspect that the installer did not put in sufficient expansion joints but he is ignoring our requests to come out to assess the situation.  Before we can take it further we need some confirmation of the cause of the problem and preferably a quote for a repair.  I am however finding it difficult to get someone to come and assess this.  I am in the Sheffield area if anyone is prepared to help.
 
Hi ANN

I have no information on how good these guys are but they seem to do a lot of drives around me. They are in the Penistone area so am sure would cover Sheffield.

Impress Drives: 01226 763273
Steve
 

ANN

New member
Hi
No trees.  We suspect it is a stress fracture  due to not enough expansion joints.  It appeared following the very hot weather in June but unfortunately we are not having any luck getting the installers to come out to assess. 
 

PeteHall

Moderator
ANN said:
Hi
No trees.  We suspect it is a stress fracture  due to not enough expansion joints.  It appeared following the very hot weather in June but unfortunately we are not having any luck getting the installers to come out to assess.

What soil are you on? Hot dry weather causes clay soils to shrink as they dry out and could easily result in your paving cracking if there was insuficient sub-base depth. Trees amplify this problem as they draw water out.

If you are unsure of your local soil conditions, you can try looknig here: http://mapapps.bgs.ac.uk/geologyofbritain/home.html
 
I had a printed drive and it didn't have any expansion joints in it - no issue with cracking (over the three years I was at that house).

Not sure a slab of that size would actually require expansion joints? Maybe some space around it (there was a gravel "gap" on one side of the driveway at our place).  Do these driveways get laid with rebar in them to take some of this stress and reduce the risk of cracking?

I'd be inclined to suspect poor foundation (lack of compaction / settlement) rather than a heat stress fracture.
 

ChrisB

Member
It's plausible that a slab could expand in hot weather and then crack rather than shrinking back again, but there would probably need to be some 'aggravating' factors. Joints in concrete are provided to allow for shrinkage as it cures, and (at longer distances) for thermal expansion and contraction. Some questions that may help a retired civil engineer diagnose the cause without having to visit:

How long is it since it was laid?
How long is the slab (at right angles to the crack)?
What is at the ends, ie, can it expand or is it trapped between (eg) a building and a road?
Is the slab all at the same slope or does the gradient change?
Does the width of the slab change (and if so, is the crack at a point where the width changes)?
Is the crack right across the slab?
Is the crack the same width all along it's length?
More difficult to check but is the crack the same width all the way down (try pushing in strip of plastic or similar)?
What does the installer's information say about the concrete mix they use, the type of reinforcement and the sub-base?

 
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