Abstract:The effect of freeze-thaw cycle to the bonding performance between steel bar and fly ash concrete was analysed through pull-out test to steel bars attached strain gages inside. The results of pull-out test under different number of freeze-thaw cycle show that the bonding strength between steel bar and concrete decrease as the content of fly ash increasing; when the content of fly ash stay the same, with the number of freeze-thaw cycle increasing, the concrete compressive strength decline, and the bonding strength decrease; as the fly ash replacement rate stay 40%, with the number of freeze-thaw cycle increasing, the ultimate bonding strength decreased speed reduce, and the free end displacement corresponding to the ultimate bonding strength increase, which shows that mixed with a large number of fly ash can remit the freeze-thaw damage phenomenon, the bonding performance of reinforced concrete specimens under freeze-thaw environment is improved.