Fig. 9 shows the bond stress–slip curves obtained after 28 days for the geopolymer concrete pull-out specimens with ribbed bars and heat cured for 7 days. When compared to the 2D curing mode results, a 25% increase in bond strength is observed. This significant increase of the bond strength led to the yielding of the steel bar followed by concrete
splitting at failure. As for both compressive and tensile strengths, increasing the duration of the heat curing from 2 days to 7 days improves the bond strength.