Interesting repair technique

[Dr Bob]

On 26/10/2017 at 11:07, rasputin said:

Closed cell?

It's closed cell so it doesn't leak. Open cell foams would allow water through. The link to geopolymers was a company called Uretec so it looks like  this is just polyurethane foam that is squirted in as a liquid and it foams in situ. The yellow colour is a bit is a giveaway. Pretty simple stuff. The pics are showing expanded PU foam. 

Cpt Pegg refers to something different - a resin with a mineral based filler...but that is what a PU foam is. I looked at the site for an MSDS sheet as that will give the chemical composition but I couldn't find one.

[Dr Bob]

Just looked at the FAQ page and it is definitely an expanding foam based on the applied density and expanding force info. The numbers look near enough for PU foam.

Edited October 29, 2017 by Dr Bob

[___]

1 hour ago, Dr Bob said:

It's closed cell so it doesn't leak. Open cell foams would allow water through. The link to geopolymers was a company called Uretec so it looks like  this is just polyurethane foam that is squirted in as a liquid and it foams in situ. The yellow colour is a bit is a giveaway. Pretty simple stuff. The pics are showing expanded PU foam. 

Cpt Pegg refers to something different - a resin with a mineral based filler...but that is what a PU foam is. I looked at the site for an MSDS sheet as that will give the chemical composition but I couldn't find one.

Well bugger me, I thought it was something more technical than that. I had started to think it may be a geopolymer cement based grout. Begs the question as to why this technique hasn't been used before if it actually works. I have previously had accountability for managing earthworks and this wasn't a technique we used at that time. I have a feeling it may still not be!

There is a bit of a smokescreen in that trade literature as to what their product really is.

JP

[Dr Bob]

8 hours ago, Captain Pegg said:

Well bugger me, I thought it was something more technical than that. I had started to think it may be a geopolymer cement based grout. Begs the question as to why this technique hasn't been used before if it actually works. I have previously had accountability for managing earthworks and this wasn't a technique we used at that time. I have a feeling it may still not be!

There is a bit of a smokescreen in that trade literature as to what their product really is.

JP

Cpt Pegg you are totally correct. I should have put my brain in gear last night! Geopolymer is a term used for inorganic polymers - not based on carbon . Typically made from a slurry of sodium silicate, aluminium hydroxide etc and cured with sodium hydroxide. Essentially are Al, Na, Si, O type structures so similar to cement. It is however much stonger. Some clever bloke reckoned this was the way they built the pyramids! More recently people have been blending in carbon based polymers i.e. PVC to form hybrids that are more flexible and impact resistant. They are commonly referred to as HIPS .....hybrid inorganic polymer systems. These geopolymers have a use as ground stabilisers but as they are expensive, I think it it more likely used in nuclear or offshore. Like you say they are more like grouts and not an expandable foam and a highly technical. Our company has actually been playing with these for a few years but not for that application.....which is why a light suddenly went on last night.

The confusion comes with the Uretec company selling a geopolymer that looks like it is a foamed polyurethane and calling it geopolymer, i.e. It is a polymer and it goes in the ground hence geo...polymer. It's like claiming my car is an electric car cause it has a battery and some wires...although the engine is diesel.

In this case the last pic I think clinches it as the stuff floats. It's a foam. Real geopolymers will have an SG nearer 2, like concrete.

If anyone who sees it is keen to find out what it is. Cut a bit of with a pen knife. If it cuts then it is a normal polymer. Stick a match under it and if it burns cleanly and melts it will be PS foam or if it burns with a smokey flame and chars then likely PU foam.

[___]

Dr Bob,

I think the colour and the buoyancy have probably led you to the correct conclusion. I was hoping that CRT might be leading the way with a new and clever asset management technique but I am not convinced this is such. So nb Innisfree doesn't stand corrected (sorry).

We shouldn't doubt CRTs understanding of earthworks management as their most safety critical pieces of infrastructure are the earthwork dams on their water supply reservoirs,

It was answering Murflynn's question that really got me thinking. It's good when a proper discussion and some learning breaks out.

JP

[bizzard]

They inject it like doughnuts are injected with custard or jam. Before taking the first bite at them search for the injection hole and bite into that, if you don't the custard-jam will squirt out of the hole at considerable pressure all over you or someone else.

[TheDuker]

15 hours ago, Captain Pegg said:

As explained. It isn't expanding foam.

Well,  . . .  it's foam, it obviously expands, and it floats. It looks exactly like the expanding foam - even the colour is right - produced primarily for use in the building trade, but that sometimes gets used for temporarily blocking vents and openings on inland vessels undergoing coastal tows.

[bizzard]

I think they need to be careful about leaving it lying about, it might get mistaken for a certain fungi, taken home, cooked and eaten.

[Dr Bob]

34 minutes ago, bizzard said:

I think they need to be careful about leaving it lying about, it might get mistaken for a certain fungi, taken home, cooked and eaten.

Ooooo.....nice!

[Hudds Lad]

now I wish I'd been cheeky and taken a pic of the barrels the stuff was coming from, would have saved a lot of guesswork 

[rasputin]

2 hours ago, TheDuker said:

Well,  . . .  it's foam, it obviously expands, and it floats. It looks exactly like the expanding foam - even the colour is right - produced primarily for use in the building trade, but that sometimes gets used for temporarily blocking vents and openings on inland vessels undergoing coastal tows.

And that stuff isn't closed cell

 

[Dr Bob]

5 minutes ago, rasputin said:

And that stuff isn't closed cell

 

PU foam can be made either closed or open cell dependent on the application. You do this by altering the formulation so that as the foaming reaction takes place, ie formation of gas bubbles, the bubbles either break or they do not. I havent a clue whether it is open or closed without looking at it - in the application shown. The advantage of open cell is that you can get a much bigger expansion so a much lower density foam (ie sg's of 0.05).. so a litre of liquid fills a much bigger hole. Why the interest in whether it is closed cell or open cell? Not trying to be argumentative...just interested.

[magictime]

If that's the lock I think it is, we passed through it a few days ago and the stonework under the offside bottom gate had completely collapsed, leaving a whacking great hole in the floor where you'd normally stand to open the gate. Had to call someone out to open it for us. Presumably this is the first stage of repair work - stopping a leak through the lock walls that has weakened the ground, maybe?

Edited October 30, 2017 by magictime

[rasputin]

45 minutes ago, Dr Bob said:

PU foam can be made either closed or open cell dependent on the application. You do this by altering the formulation so that as the foaming reaction takes place, ie formation of gas bubbles, the bubbles either break or they do not. I havent a clue whether it is open or closed without looking at it - in the application shown. The advantage of open cell is that you can get a much bigger expansion so a much lower density foam (ie sg's of 0.05).. so a litre of liquid fills a much bigger hole. Why the interest in whether it is closed cell or open cell? Not trying to be argumentative...just interested.

 

14 hours ago, Dr Bob said:

It's closed cell so it doesn't leak. Open cell foams would allow water through. 

Also I suppose I am a bit anti open cell on boats, so maybe you are right and it doesn't mater as long as it retains its integrity

[nb Innisfree]

1 hour ago, rasputin said:

And that stuff isn't closed cell

 

The same stuff I've used has been waterproof with no sign of absorbency so it must be closed cell. 

[WotEver]

Quite a concise article here comparing the differences:

https://www.thomasnet.com/articles/plastics-rubber/closed-cell-open-cell/

[nb Innisfree]

3 hours ago, bizzard said:

They inject it like doughnuts are injected with custard or jam. Before taking the first bite at them search for the injection hole and bite into that, if you don't the custard-jam will squirt out of the hole at considerable pressure all over you or someone else.

Take a can of aerosol cream and inject it into the jam hole (ooh missus) stop injecting before it splits the doughnut, mmm. 

[Dave_P]

Presumably they're going to clear that mess up?

[nb Innisfree]

13 minutes ago, Dave_P said:

Presumably they're going to clear that mess up?

If not put them in a closed cell... 

...coat

[rasputin]

1 hour ago, nb Innisfree said:

The same stuff I've used has been waterproof with no sign of absorbency so it must be closed cell. 

But that isn't my experience, I have had 2 boats where I have had to remove sodden so called closed cell PU

[matty40s]

Found some more in Loughborough Lock....

[Hudds Lad]

1 hour ago, matty40s said:

Found some more in Loughborough Lock....

That's the new CRT cash cow in action, by filling the cut with foam they can save up to 50% of water levels & attract the Ibiza Foam Party set to the canal to boost visitor numbers yet further, plus whilst said "ravers" are off their collective swedes on recreational pharmaceuticals they can charge them £30-40 each for the privilege

[ditchcrawler]

They were doing this today on Congleton Aqueduct when we went by. Note they had a floating sausage to catch leakage