Concrete under tension - relation between crack opening and cracking strain?

[drennon236]

I need to find the cracking strain; which is the total strain minus the elastic strain corresponding to the undamaged material. So I am wondering, from the posted picture, how can I find the cracking strain? - is it the strain from 0.9*f_ctm to f_ctm in the first picture?

 

[AndrewFinAustralia]

Hard to tell.

You'd need to see the full article. I read the 0.9 f_ctm as being 10% factor of safety in the loading. I have no idea what the 'ctm' stands for in this instance. It just indicates to me that a strain from 0.11 to 0.15 occurred with no major increase in stress (ie: deformation was commencing in some way, shape or form.) Think metals as they approach their UTS. I'm unsure of the paper and can't answer further.

Being concrete, it probably starts microcracking at lower strain, which is not apparent to the naked eye.


Regards,