Expansion joint in concrete

[Araucaria]

I'm part way through putting down a concrete floor in the hangar. When finished it'll be a single concrete floor of about 100 m2, in three bays each a bit more than 3m wide and 10m deep, and so far I've poured the two outside bays. I've now got the middle section to do between the two that are already done.

I feel I ought to provide for a bit of expansion between the sections. I remember seeing a hard-ish closed-cell foam strip - self adhesive I think - that the builders used around the walls of our bedroom when they were pouring in the stuff (technical term) on top of the hot-water heated floor. It was about a centimetre thick, and I'd guess probably 20cm wide - perhaps not thick enough for a big sheet of concrete? I'm not sure if that actually is what I need - but does anyone know what product I should use in concrete, and, more importantly, what it's called in French?

It's not important what it looks like, and I'm not looking for a really smart finish anyway. I did consider leaving the shuttering boards in place, but it turned out I needed to re-use them (I'm putting an inspection pit in the middle section).

[Chancer]

Un joint de dilatation.

They are usually an inverted T profile in pvc.

You set them on blobs of mortar and they serve as screeding rails.

[ventodue]

[quote user="Araucaria"]<snip>  I feel I ought to provide for a bit of expansion between the sections ... I'm not sure if that actually is what I need - but does anyone know what product I should use in concrete?[/quote]

Essentially, what you're trying to do is to allow the slabs to move independently of each other* - and  move they will, be it by contraction, expansion or settlement.  So you want something that can take up that movement.  Now you can buy specially-designed plastic profiles, like this ...

http://www.leroymerlin.fr/v3/p/produits/joint-de-dilatation-80-mm-x-5-m-e163240

 ...which are ok, but are possibly a bit more expensive than necessary for what you’re doing.

Fortunately, a few strips of fibre board, cut to size and left in place, will also do the job [:D].

* Have a look here, if you like, where there is a not-all-bad explanation of what you're doing and why [:)]

http://www.pavingexpert.com/concjnt1.htm

[Araucaria]

Thanks very much - I'll probably go for the fibreboard option as my slabs are mostly quite thick (up to 20cm) and those plastic sections are only 8cm deep.

Do either of you have any views on caniveaux? When I previously put some down I went for the (in my view) rather expensive option of the ones from Chausson in béton polymère - about €40 a metre (and I'll need at least ten): are their cheaper options elsewhere that won't break up when I drive a car across them?

[ventodue]

[quote user="Araucaria"] Do either of you have any views on caniveaux? [/quote]

My main view is that it's not a job you want to have to do twice! [:@].    But I also understand that neither do you want something that might be suitable for the rebuilding of Marseille docks ... [:-))]

Have a look at the Aco site here - should give you an idea of the quality of product that you need - e.g. their 'Self' range, perhaps?

http://www.aco.fr/guide-de-choix-caniveaux.html#

[Araucaria]

In scrabbling about for alternatives I found that Brico Depot do caniveaux much the same as the Chausson €40 jobbies, but at only €10 a metre.

The Chausson one is actually the product you linked to (or at least they are both called "Self"), while the Brico Depot one looks the same - and I will find out tomorrow if it is. It's made of the same material, beton polymerique, anyway.

It is only for a garage entrance, so it's what they are designed for, and it'll be well-embedded in concrete..

So thanks for all the suggestions.

And I may well end up with polystyrene for the expansion joint, as I can't find fibreboard locally, and the concrete arrives on Friday.

[Théière]

From memory yes the Brico Depot is the same material and if bedded down properly will be very suitable unless your car is more than 5 tons which is the weight most of the smaller ones are capable of taking including the ACO plastic range.

Which polystyrene, extruded or expanded?  expanded will break up eventually but extruded maybe too strong at around 40 tons/per metre

[Chancer]

I am using cheapo Brico-depot ones, they are plastic but very rugged, once Embedded in concrete they are very strong and will resist all wheeled traffic.

I think that they may need a greater fall than the ACO ones as silt builds up at the joints in mine.

[Araucaria]

I can confirm that the BricoDepot ones at €10 are exactly the same as the ones from Chausson for €40 - Aco Self, in béton polymere.