[peteeng]

Evening all - For Ozzies here. Boral make a high modulus concrete called Aspire 50... E=50GPa out of the box... Trying to find out its aggregate. Peter

[mactec54]

Evening All - Up to cast No2. I have 2mm long steel fibres that I have been playing around with for a while. I have infused these with epoxy and now have chucked some into CSA grout. Both times have not come up to expectations... They clump and don't pack well. Especially they change the rheology of the CSA quite a bit... I wanted to add 1kg of fibres to the mix but didn't get past 0.5kg... Gave my Bosch drill quite a work out. When I poured it out into the mould it looked like the durcrete stuff in the video. It sort of climbed out of the bucket in large drips. But when it hit the mould it smoothed out... My target has been a E70 mix but that won't happen here. I expect if the maths are right to get 40-45GPa out of this mix so must be similar to Durcrete E45 material I think....... Now to make a mould to do some modulus testing... I wonder if I can infuse with water? Peter

I tried some metal chips I had saved from milling only added about 2% and just slowly added while mixing to stop clumping a snip of some of my save Chip from milling they are about 1" to 3/4" long so mixed quite well are trying some Glass fiber in my next blocks when I get time

[peteeng]

Morning All - Lets keep the discussion technical and share information. Its up to everyone to filter the information as required and keep it topical not personal. We are previleged to be able to participate in this sort of forum so be happy and make stuff and share here Peter

[peteeng]

Hi Mactec - My addition rate target is much higher then 2% by wt. To get to E70 (equivalent to aluminium) with steel and grout I need to add 60% steel by volume (if the strain transfer efficiency is 0.5) if they are long fibres then the efficiency is 1.0 and I'd only need 25% by volume. High quality long fibre laminates typically run at 50-55% volume fractions even 60%. Your swarf would be a long fibre so say we want E70. So (200*0.25*1)+(26*0.75)= 69.5GPa modulus. By weight this is (.25*7800)+(0.75*2100)= 1950+1575=3535kg/m3 so steel weight ratio is 1950/3535= 55% by weight.... If you put some swarf in a known volume you can figure out its bulk density and see if this figure can be achieved.... struggling on.. I'm off to release Block No2...Peter

So its released and looks good. Its stats are density 2356kg/m3 and its fibre content by weight is 17% (not addition rate actual proportion)and by volume is 6%. So the maths say its modulus is (200*0.06*0.5)+(26*0.94)= 36Gpa so a small step fwd but by using blue metal the supplier says it will get to 40GPa and Boral is making it at 50GPa so still need an answer. Have to buy some alox... The moulded surfaces of Block 2 are very good. need to test to see how good the figures are next step... Peter

[ardenum]

Hi Mactec - My addition rate target is much higher then 2% by wt. To get to E70 (equivalent to aluminium) with steel and grout I need to add 60% steel by volume (if the strain transfer efficiency is 0.5) if they are long fibres then the efficiency is 1.0 and I'd only need 25% by volume. High quality long fibre laminates typically run at 50-55% volume fractions even 60%. Your swarf would be a long fibre so say we want E70. So (200*0.25*1)+(26*0.75)= 69.5GPa modulus. By weight this is (.25*7800)+(0.75*2100)= 1950+1575=3535kg/m3 so steel weight ratio is 1950/3535= 55% by weight.... If you put some swarf in a known volume you can figure out its bulk density and see if this figure can be achieved.... struggling on.. I'm off to release Block No2...Peter

So its released and looks good. Its stats are density 2356kg/m3 and its fibre content by weight is 17% (not addition rate actual proportion)and by volume is 6%. So the maths say its modulus is (200*0.06*0.5)+(26*0.94)= 36Gpa so a small step fwd but by using blue metal the supplier says it will get to 40GPa and Boral is making it at 50GPa so still need an answer. Have to buy some alox... The moulded surfaces of Block 2 are very good. need to test to see how good the figures are next step... Peter

Will you be making a vibration damping test rig or you're going purely for stiffness?

[peteeng]

Hi Ard - Measuring the vibration decrement is a bit tricky DIY. All the literature & evidence says concrete, EG etc are 10x 20x damper then metals so that's good enough for me. My main issue is getting an accurate modulus for design purposes so I'll be just measuring E... In another thread Thomas is using Silimix/epoxy so I'm writing a white paper on DIY E measurement. I'll put it up here once its done. Drowning in things to do again I need a few minions.. Peter

[mactec54]

Hi Mactec - My addition rate target is much higher then 2% by wt. To get to E70 (equivalent to aluminium) with steel and grout I need to add 60% steel by volume (if the strain transfer efficiency is 0.5) if they are long fibres then the efficiency is 1.0 and I'd only need 25% by volume. High quality long fibre laminates typically run at 50-55% volume fractions even 60%. Your swarf would be a long fibre so say we want E70. So (200*0.25*1)+(26*0.75)= 69.5GPa modulus. By weight this is (.25*7800)+(0.75*2100)= 1950+1575=3535kg/m3 so steel weight ratio is 1950/3535= 55% by weight.... If you put some swarf in a known volume you can figure out its bulk density and see if this figure can be achieved.... struggling on.. I'm off to release Block No2...Peter

So its released and looks good. Its stats are density 2356kg/m3 and its fibre content by weight is 17% (not addition rate actual proportion)and by volume is 6%. So the maths say its modulus is (200*0.06*0.5)+(26*0.94)= 36Gpa so a small step fwd but by using blue metal the supplier says it will get to 40GPa and Boral is making it at 50GPa so still need an answer. Have to buy some alox... The moulded surfaces of Block 2 are very good. need to test to see how good the figures are next step... Peter

I see what you are trying to achieve with the steel

I'm just going off of what Trinic use they don't use steel mostly only Glass fiber So I will try more and see how it goes, they don't use steel much because of the possible rusting as it can get too close to the surface, then it will rust and cause cracking

[peteeng]

Hi Mactec - Yes rusting is a possible problem, I can get stainless steel fibres but more $$$ and plain steel is OK for development. The steel I have I've washed in solvent and put outdoors and it does not rust so I'm not sure what it is...

Glass fibre is 70GPa and as its made from melted sand (Sio2) so its the same stuff just long cylinders vs sort of spherical. There's lots of basalt fibres (basalt is blue metal aggregate) as well but they are 70GPa as well so no delta there. So I think packing the fibres is the issue. That's where infusion shines as the vac bag compresses the stack very nicely... I'm thinking of trying a water infusion with the CSA... The european E80 material is really what I want to replicate...If I could buy the E80 I would...Prefer a mix and pour solution to setting up a vac bag...Peter

[hanermo]

Please measure the E or bend ..

[peteeng]

Hi All - I was not happy with the Block 2 process. B2 I mixed the grout then mixed in the fibres that got my drill really hot!! So I thought this is the same as cooking, mix all the dry stuff together first. So I replicated Block2 recipe but mixed the fibres and grout dust first. Hard to see the fibres in the dust! Once I was happy the dry stuff was mixed I then set up the correct water mass and started adding to it in small amounts till the end. This worked really well. It poured this time instead of crawling... This now gives me hope that I can get more steel in.. But I think I need to use a better mixer. Will find my old corded drill.... Peter

It is also de-airing well, it bubbles away...

[catahoula]

looks great pete, excited to see how it continues to go. after all the hassle of welding/stress relief/blueprints for machining i'm kinda wishing i went with one of my former plans of casting both an EG or CSA base and gantry against a 24"x36" surface plate. Then I'd have an extra surface plate for the price of the shopped-out machining and still a lot left over. but.... buy the ticket, take the ride

[peteeng]

Hi Cat - The ride can be wild and disappointing but sometimes when the stars line up its a great feeling... Peter I went back through some of my dry stack data for the steel fibers and one test showed the max dry fibre stack I could get was Vf=14% Block 2 was Vf=6% so next block I'll shoot at 1kg of fibres and 12-14% Vf... Thats going to be a thick mix.... perhaps creep up on it...I also have some aluminium powder here I can try....Peter

[peteeng]

Hi All - Here's some info on calculating your material modulus... Peter

[ardenum]

Can you guess by the color what material the headstock is made of? it starts with an E8...wink, wink

https://i.imgur.com/1rLL3EO.png

Doing it otherwise turned out to be a major pain in the ass.

[ihavenofish]

used chewing gum?


:P


I'm confused about the axis arrangement though.

[peteeng]

Hi Ard - Your learning, so your in the EU? IHNF I think he has only shown half of the machine. Peter

[peteeng]

Afternoon All - Took advantage of some free time today to do Block No4... I read back through my notes and saw that a dry stack of fibres was 14% volume ratio so that's the most steel I can put in it. So I calculated out a 10% Vf batch and got busy. This is a 42% addition by weight. Its twice as much as the prior batch and I was going to go half way... BUT. So I get busy batched out the ingredients and start mixing the dry stuff with my old Ryobi. It gets along OK but then slows down and goes BANG, hot black plastic thrown around the area. So back to the Bosch. I look at the batch and think its a bit big so halve it and add the required min water and its still crumbly so add the extra water to the max 25% ratio and its just bread crumbs. So add a little extra a couple of times and it comes together like a dough. It won't pour and it seems to be stuck in the bucket so I leave it there. Tomorrow I'll cut it out. At 10% Vf the estimated E low is 34GPa (n=0.5) and E high is 43GPa (n=1.0)... I may as well buy grout at 34GPa and its a done deal.... The steel fibres aggregate, entangle and are not friendly... have to be able to add much more to get to the target E70... So its ALOX next... You guys in europe just buy the E45 or E80 material so much easier.... I do like the concrete vs the epoxy, water clean up is great and reuse the buckets etc Peter

Re: Aspire 50 its only batched and not available in bags. Called Boral today about it. The data sheets don't say what the aggregate is just the usual silica portland flyash etc...

[peteeng]

Hi Ard - Now your a cast convert why not the other parts as well?? Especially if you have access to E80 material?? E80 material is just a dream down here in Oz... Peter

[ardenum]

Hi Ard - Now your a cast convert why not the other parts as well?? Especially if you have access to E80 material?? E80 material is just a dream down here in Oz... Peter

Not sure about longevity, once I make this I want it to be functional(structure wise) for 50 years. I doubt the company can guarantee that the E80 beam structure will still be viable after 50 years of vibrations. But who knows, maybe I will have to compromise once I sum up all the costs...

Regardless of the properties, I still see this as a 'concrete'. Maybe that's where my hesitancy comes from.

[peteeng]

Hi Jon - The E80 material was specially developed for machine parts. Not for construction. To provide 50 year guarantees for anything is tough. The grout I have here can be guaranteed for 100 years by the supplier and I see no difference to the UHPC that's made in Europe. Time will tell. Roman concrete structures have been around for 2000 years plus...and they used the wrong engineering formulas to design their structures!! Peter

https://en.wikipedia.org/wiki/Roman_concrete