The UBC 97 clearly states that it is 1" for tilt up walls But in the current ACI-318-11, it seems to be vague, is it 3/4"? The walls are cast on site and not at a plant. Also where is this in the CBC-2013 or ACI 318-11?
Site cast tilt-up is usually considered the same as precast, so ACI 318-11 7.7.3 would apply. Also see ACI 301-10 Table 3.3.2.3(g) - these are the same requirements as in 318.