The load-slip relationships for all the specimens tested in this investigation are shown in Fig. 6 (a-d). Itwas found that, for all low strength concrete specimens, the average peak pull-off loads were 20.83 kNand 25.85 kN for specimen LS7.5-DB12 and LS7.5-DB16 respectively. For normal strength concretespecimens, the average peak pull-off loads were 52.10 kN and 55.89 kN for specimens NS26-DB12and NS26-DB16 respectively. The average peak pull-off loads of normal strength concrete specimenswere significantly higher that those of low strength concrete specimens.