Q.: Regarding reinforcement in slabs, please clarify whether you find a rebar spacing of 16 inches as good in reducing crack widths as a spacing of 6 or 8 inches, assuming there is the same total area of reinforcement in any case.

A.: Theoretically there is no difference because the restraint to movement is the same in all cases. Close examination of the distribution of fine cracks might show them to be slightly more uniform in size and spacing when the rebar spacing is smaller but the difference is perhaps not very important.