冻融循环作用下纤维编织网增强混凝土加固梁的受弯性能

FLEXURAL PROPERTY OF RC BEAMS STRENGTHENED WITH TRC UNDER FREEZE-THAW CYCLE

采用四点弯曲加载的方式研究冻融循环作用下冻融循环次数、纤维编织网增强混凝土(TRC)黏结剂、TRC型式和弯曲应力水平等因素对TRC加固梁性能的影响。结果表明:冻融次数越多,承载力下降幅度越大,梁越容易发生剪切破坏;用细粒混凝土将预制TRC板粘贴到梁底,在限制裂缝、承载力及挠度变形方面所表现出来的性能与现浇TRC加固很接近,而用结构胶粘结预制TRC板在各方面性能的表现不甚理想;弯曲应力水平越大,试验梁经过冻融循环的极限承载力下降越多,梁的变形越大。冻融循环对TRC加固梁有较大影响,使得梁的破坏模式、极限承载力和挠度有所改变,但在整个试验过程中,TRC对梁的加固保持较好的作用,使梁的裂缝发展得到了较好的控制。

By the four-point bend loading mode,the influence of freeze-thaw cycle times,TRC binder,TRC form and bending stress level under freeze-thaw cycles on the flexural behavior of RC beams strengthened with TRC were considered. The results showed that the bearing capacity of the beam exhibited a great decrease with the increase of the number of freezing and thawing,and the beam was prone to shear failure. Precast TRC panels bonded to the bottom of the beam by high performance concrete was close to the casting TRC in restriction of crack,bearing capacity and deflection. However,the properties of precast TRC panels bonded to the bottom of the beam by organic adhesive were not ideal in all aspects. The ultimate bearing capacity of the beam under freezing and thawing cycles exhibited a more decrease with the increase of bending stress level. Therefore,the freeze-thaw cycles had a great impact on the beam strengthened with TRC,and the failure mode,ultimate load and deflection of beam were changed. In the whole experimental process,TRC had a good effect on the reinforcement of the beam,so that the crack development of the beam had been improved.