Thanks all for the input. One paper about the same topic goes in detail about strength comparison between cubes of different sizes to cylinders of different sizes too. I was just concerned about the state of the inner core of the specimens but I'll try some of the suggestions above and see what...
EngineeringEric, TXStructural and cvg, Thank you for your contribution.
I'm not using cylinders because their surface would require end grinding (capping doesn't work with high strength), and the end-grinder is not available.
I will use more amount of superplasticizer, however I'm not sure...
I hope this is the right forum to post in...
(For Research) : I'm trying to do a concrete mix (mortar for now before adding fibers) with strength above 18 ksi (120 MPa) at 28 days. So at 7 days I need at least 15 ksi. This is known as ultra high performance concrete and many researchers even...
