冻融下预湿方式对塑钢纤维轻骨料混凝土与钢筋粘结性能的影响

Bonding properties of plastic fiber reinforced lightweight aggregate concrete and steel bar under freezing-thawing

通过常压预湿和加压预湿两种方式对烧结页岩陶粒轻骨料进行处理,探究不同冻融循环次数下,塑钢纤维轻骨料混凝土与钢筋的粘结性能,着重分析了两种预湿方式下试件力学性能、粘结强度、荷载滑移曲线、粘结韧性的变化规律。试验结果表明:加压预湿试件的力学性能、极限粘结强度低于常压预湿试件,且加压预湿试件的破坏形态均为劈裂破坏;加压预湿试件的极限粘结韧性Au随冻融循环次数增加而减小,残余粘结韧性A_(80)、A_(60)下降较为平缓,但常压预湿试件粘结韧性均高于加压预湿试件。建立了冻融环境下塑钢纤维轻骨料混凝土剩余粘结强度与抗压强度之间退化模型和粘结韧性退化模型,模型计算值与试验值吻合较好。

The sintered shale ceramsite lightweight aggregate was treated by the atmospheric pre-wetting and pressurized pre-wetting.The bonding properties of the lightweight aggregate concrete and the steel bar under different freezing and thaw cycles were investigated.The mechanical properties,bond strength,load-slip curve and bond toughness of the specimen under pre-wetting were analyzed.The experimental results show that the mechanical properties and ultimate bonding strength of the preheated wetting specimen were lower than those of the pre-wetting specimen,and the failure modes of the pre-wetting specimen were all fractured.The ultimate bond toughness of Audecreases with the increase of freeze-thaw cycle,and the residual toughness of A（80） and A（60） is relatively flat,but the bond toughness of the pre-wetting specimen is higher than that of pressurized pre-wetting specimen.Under the freezing and thawing environment,the bond toughness degradation model and the degenerative model of the residual strengthand compressive strength of the steel fiber lightweight aggregate concrete were established.The calculated values of the model were in good agreement with the experimental values.