According to ACI 313-97....
(Cement, clinker)
Density - 88#/ft^3
Internal Friction phi - 33 degrees
Effective Internal Friction delta - 42-52 degrees
Friction against wall mu prime - .6 concrete, .3 steel
(Cement, portland)
Density - 84 - 100 #/ft^3
Internal Friction phi - 24 -30 degrees
Effective Internal Friction delta - 40-50 degrees
Friction against wall mu - .4 - .8 concrete, .3 steel