Quote Originally Posted by badhabit View Post
I haven't done much research into EG vs. UHPC, it mostly seems like a "religious war" and in my opinion there is not a clear "winner". The biggest downside to UHPC (as far as i've research!) is that it behaves like a concrete(duh!) so it keeps "moving" for a very long time. EG does not, but it then have other properties that are undesireable(toxic before hardening, non-newtonic makes degassing problematic, it is a plastic makes process "dirty" and recycling hard etc) and EG is very(purely) dependent on the aggregate to get a good result(=high modulus)..

A modulus of 12 seems wrong, epoxy in itself is something like 3-4ish. So 12 seems low...i would expect at least double for a "professional solution".... i really need to do the test on my(and Stefs) mix using Silimix282... What was the coupon-size you cast for the test you made? Were your samples "perfect smooth square" or did you have an "open side" on your mold giving an rough side? I was thinking about casting a 800x20x20 coupon and stuffing it from the end making all sides smooth, but i'm worried about the air affecting the result "unfair" due to the narrow cross-section...and making the crosssection bigger increases the forces required to make deflection very quickly....

I haven't seen any information from Stef regarding accuracy tests for his machine, but his surfacefinish looks spot on(in aluminium though)....so that is mainly what i based my comment about Stefs machines performance on....

/Thomas
I just glanced through this paper - which surveys many previous research on this subject (Only epoxy based I think). And it shows a table of various previous researches. For me it looks like many of the researches report EM below 20 for EG. This seem to be agree with Pete's observation of 17 GPA.
Since the aggregates I used had max size of around 15mm, Pete suggested I have a minimum cross section of at least 40mm and length of 800. So my specimen was 50x50x1000mm. Its was a full solid block/beam. It was not that difficult to deflect. I applied forces starting from 4Kg up to 17Kg and measured the deflections which ranged from 3um to 16um.