A possible boost for Optiblend and Hythane?, page-15

LOL I spat my coffee out reading that

20MPa? Segments? I’m talking about the truckloads of pre-tensioned Planks and Super-T’s (and their international equivalents) that are pumped out constantly pretty much everywhere around the world.

it varies depending on design but in the region of 35 MPa, I’ve seen 40 MPa discussed as questionably achievable. This is all done with heated moulds, steam curing.
Removal from the mould means you’re de-stressing the rams and transferring the prestress force to the member so it need to be mature enough to not crush or crack with a significant factor of safety built in.

You can’t just throw 100MPa+ mixes into a mould LOL, the higher the strength the more brittle and the harder to control spalling in fire. You’d normally have polypropylene fibres for that even with a design strength of 50MPa which is pretty much universally what’s specified for this kind of thing in Australia.

final strength is higher but it’s like, design specifies 50MPa, get 36 at transfer, pass 50 by the time it’s on site, 65 after a month or so.

Also the more cement and faster reaction the more autogenous shrinkage and heat, the final strength always comes in higher than specified since the process is controlled by transfer but you’re talking out of your ass saying 65MPa 1 day strength can be used in infrastructure.

The notional use of CNT in this context would be increasing the strength at transfer without the problems caused by higher strength concrete, and increasing the flexural tensile strength which controls the amount of prestressing required in the first place.
Whether the latter could be used in design is a bit up in the air but the former is a matter of crushing a cylinder

Possibly improvements for 50MPa concrete not that great?would love to see actual data, and there may be some possible durability issues that need to be studied before CNT would get acceptance.

I’m not actually arguing this company has a future but the pseudo technical slagging of CNT “you can just X” by people who clearly don’t know what they’re talking about is irritating.