牛建刚　谢承斌　郝吉

摘要：

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A80、A60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結韧性退化模型，模型计算值与试验值吻合较好。

关键词：常压预湿；加压预湿；混凝土；粘结性能；冻融环境

中图分类号：TU528.1

文献标志码：A文章编号：16744764（2018）03006607

Abstract：

The sintered shale ceramsite lightweight aggregate was treated by the atmospheric prewetting and pressurized prewetting. 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， loadslip curve and bond toughness of the specimen under prewetting 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 prewetting specimen， and the failure modes of the prewetting specimen were all fractured. The ultimate bond toughness of Au decreases with the increase of freezethaw cycle， and the residual toughness of A80 and A60 is relatively flat， but the bond toughness of the prewetting specimen is higher than that of pressurized prewetting specimen.Under the freezing and thawing environment， the bond toughness degradation model and the degenerative model of the residual strength and 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.

Keywords：

atmospheric prewetting； pressurized prewetting； concrete； bonding properties； freezing thawing environment

中国北方严寒及寒冷地区的混凝土结构主要受冻融侵蚀。严重的冻融损伤可致使混凝土构件无法继续承担荷载，缩短了混凝土结构的使用寿命。钢筋与混凝土的粘结性能是影响构件结构力学性能退化的主要原因之一[1]。因此，在严寒地区工程中，对混凝土粘结性能研究至关重要[2]。

轻骨料混凝土密度小，混凝土结构自重较轻，表面多孔，可增强混凝土的抗冻性，但轻骨料混凝土强度低，易发生脆性破坏[34]。为了解决这一缺陷，在水泥基体中掺加纤维是最有效的方法，塑钢纤维具有质轻、耐腐蚀等优点，掺入轻骨料混凝土中能明显提高其韧性及其他力学性能[56]。……