冻融环境下钢筋与粉煤灰混凝土的粘结性能
Bonding properties between reinforcement and fly ash concrete under freeze-thaw cycle

通过对内贴应变片钢筋的直接拔出试验，分析冻融作用下粉煤灰掺量对钢筋与粉煤灰混凝土间粘结性能的影响，得出冻融循环作用对钢筋与粉煤灰混凝土之间粘结性能的影响规律。试验结果表明：钢筋与粉煤灰混凝土的粘结强度随粉煤灰掺量的增加而降低；当粉煤灰掺量一定时，随着冻融循环次数的增加，混凝土强度有所下降，钢筋与粉煤灰混凝土间极限粘结强度降低；当粉煤灰掺量较大，达到40%时，随冻融次数的增加，钢筋粉煤灰混凝土试件极限粘结强度的下降幅度明显减缓，极限粘结强度对应的滑移量增大。表明掺入较多粉煤灰可使试件的冻融损伤现象得到缓解，冻融环境下钢筋混凝土的粘结性能得到提高。
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.