Polyurethane Floor Slab Compressive Strength

[Kevin Yeo]

Hello guys,

By using 150 mm thk, 45 kg/m3 polyurethane as floor slab. What is the compressive strength of the slab? Is there any standard value for this material at this density?

Appreciate your help...

Rgds,
Kevin

[US Iceman]

Hi Kevin,

The physical properties of materials are normally available from the manufacturer. Have you tried that source?

Are you using the plastic as a covering for concrete floors in coolers or freezers?

Another property you may be interested in is the coefficient of expansion for temperature changes in the space where the plastic is installed.

[Peter_1]

I don't think that he will use plastic but polyurethane foam under the upperfloor.

45 kg/m³ is the same density we're using.

What do you mean with What is the compressive strength of the slab? Is there any standard value for this material at this density?

We dig the terrain ou till a depth of 60cm.

Underconcrete floor of 20 cm.

In the middle of this floor the heating tubes or above the floor the electrical heating mats.

Install also some probes to check the temperature.

Then install the vertical panels.
When installing them in U shape profiels, be cautious that you don't drill in the heating tubes.

Very, very important: remove +/- 15 cm of the inner steel to avoid cold-bridges towards the underfloor.
Install the door.

Then the PU-foam, preferable 2 layers, seems not over each other.
Leave at one sides a space so that you can foam it very tight with the PU foam in compressed bottles.
The PU of the floor must touch the PU of the vertical panels without any gap.

Or cut the last pieces in a triangle so that you can jam them against the walls.

Tape a small vertical expandable strip of +/- 25 cm high so that the concrete doesn't touch the panels where the floor can expand afterwards while freezing it.

Over the PU foam, place plastic foil to protect the PU- foam, bend them +/- 1 m upwards and attach them with tape on the vertical panels (to avoid that concrete dirts splashes on the panels)

Pour second upper floor.

Cut away plastic foil and expanable strip.

Oh, don't forget to install the cooling system.

Avoid heavily freezing within 28 days after pouring the concrete.

Install a heated pressure relief valve in the panels.


If interested, I can make a sketch of all this.

Hope this was helpfull.

[frank]

Oh, don't forget to install the cooling system.

Nice one Peter

[US Iceman]

I don't think that he will use plastic but polyurethane foam under the upperfloor.

You are correct Peter. I did not think of the PU being the floor insulation. I suppose I should have paid more attention to his request.

[Peter_1]

We're here to help each other and one fills the gaps in the thinking of the other.
This was once completely different

[Kevin Yeo]

Hi Peter & Iceman,

The floor requirement requires strength of 50 kpa on the wearing concrete slab & super flat floor. To achieve this, post tension concrete slab will be employed. However, the question here is whether the load of 50 kpa can be transferred to polyurethane slab (45 kg/m3) and eventually distributed evenly to the ground beam / slab.

So I guess, the ability of polyurethane to withstand such load will depends on its compressive strength since the loading pattern is of continuous (warehouse application) and compressive.

Peter,

We normally cut away the bottom portion of galvanised steel (colourbond or this is wat we call it) allowing polyurethane to be in direct contact with floor pu slab by using in-situ pu injection. As for the BRC wire mesh or Y-bar, we insist the concrete applicator to use spacer to that the pu slab will not be affected.

Thanks for your valuable input, i'll try to get the properties from the manufacturer.

Rgds,
Kevin

[Peter_1]

The technique I mentioned is used for freezers 50 x 30 x 10 m high ,stacked till the roof where reach trucks drive in and out, so it will widthstand all the load I suppose.

Indeed, the spacers in the concrete floor I forgot, but they're not there because they shouldn't touch the PU foam.

If they're not installed halfway the concrete floor, then they add nothing to the strength of teh floor itself.

On the mesh of the underfloor, we tie with cable binders the tubes for the heating in several ciruicts (distance 30 to 45 cm)

[cruzeiros]

I would like a "sketch" for the floor detail please.

Have you ever used sand to cover the electrical heaters ?

Thanks,
Cruz.