冻融环境下钢筋与粉煤灰混凝土的粘结承载力

通过对粉煤灰混凝土试件的直接拔出试验,分析粉煤灰掺量与冻融作用对粘结试件的初始滑移粘结强度、劈裂强度、极限粘结强度及粘结强度-滑移曲线下的面积作为粘结试件韧性评价指标的变化规律.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;试件粘结韧性随粉煤灰掺量的增加先降低后增强,粉煤灰掺量较大的试件在加载过程中表现出良好的韧性;冻融作用对试件极限粘结强度的影响程度随粉煤灰掺量增大而减小,40%粉煤灰试件在冻融环境下表现出较好的粘结韧性.掺入较多粉煤灰可以在一定程度上减缓粘结试件的冻融损伤.

Bond Capacity of Reinforcement to Fly Ash Concrete under Freeze-thaw Cycle

Through the direct pull-out test of the fly ash concrete specimens,it was analyzed for change rule of fly ash and freeze-thaw on initial bond strength,bond slip the splitting strength,ultimate bond strength and the toughness evaluation index which expressed as an area under the bond strength slip curve. The results of pull-out test with different fly ash dosage and freeze-thaw cycle number show that the bonding strength between steel bar and concrete decreases as the content of fly ash increasing;bond toughness decreases and then increases with the increasing of fly ash dosage,large dosage of fly ash specimen showes good toughness in the loading process;the influence of freeze-thaw action on ultimate bond strength decreases with increasing of fly ash,40% fly ash dosage specimen under freeze-thaw environment showes good toughness. The addition of much fly ash can slow down the freeze-thaw damage of bonded specimens to some extent.