钢筋与粉煤灰混凝土在冻融环境下的粘结锚固

ANCHORAGE AND BOND 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,分析冻融循环与粉煤灰掺量双重因素对直接拔出试件粘结性能的作用。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;粉煤灰掺量一定时,粘结性能随冻融循环次数的增加而降低;当粉煤灰掺量较大,冻融作用对试件极限粘结强度的影响程度明显减小,拔出荷载沿锚固段均匀稳定地传递,钢筋自由端滑移量增大,证明掺入较多粉煤灰可在一定程度上减缓粘结试件的冻融损伤。

Through pull-out test to steel bars attached strain gages inside, the effect of freeze-thaw cycle and fly ash content to the bonding performance of specimens were analyzed. The results of pullout 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 bonding strength decrease;as the fly ash replacement rate stay40%, with the number of freeze-thaw cycle increasing, the ultimate bonding strength decreased speed reduce,the pull out load along anchoring steady transmission, 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.