Factors That Affect Bond

Mean bond strength data from 212 tests of black bottom bars (bars with untreated surfaces with concrete cover not smaller than one bar diameter and bar spacing not smaller than two bar diameters) of different diameters (from 3/8 to 1.7 in.) in normal weight aggregate concrete are plotted in Figure 26.1. The compressive strength of the concrete ranged from 2600 to 9900 psi.