The answer for the coeficient of limiting friction between the materials listed is given in table 19 of BS 5975. I don't have a copy with me at this moment.
Values you will find in a book will be general, but may be close. You will want to look for a value for your specific condition though. Will the mortar or concrete be wet (that is, uncured not surface wet) when the steel is placed against it? If so, the initial, one time only, static coefficient of friction will be higher than once the bond is broken. Also make sure you are getting the static or dynamic coefficient of friction to fit the condition you are concerned with. Again, if you can find these values, they will be only general ranges. the specific steel and mortar or concrete can make a big difference.
From alot of experience, I can tell you that I've seen the values for static coefficient of friction of the same piece of neolite, resurfaced identically, to various ceramic tiles range from .35 to .9 using the exact same testing procedure, ASTM C 1028.
You might do a web search using "mortar, steel, coefficient, friction," and then narrow it down with ASTM 1028 if needed.
Andy Machon above said look at BS 5975 Table 19. (BS for design of falsework) I've just done that and it gives a minimum value of mu for steel on concrete of 0.1
In the past, I have used a value of 0.5 for concrete floor planks restraining the compression flange of steel beams, on the understanding that it is really more like 1.0 in practice, and this has been accepted by checking authorities. In reality it is probably quite variable, and the value you use will depend on why you need to know it!
Good luck.
Richard
