织物增强混凝土薄板加固钢筋混凝土梁的二次受弯性能试验研究

为研究织物增强混凝土(TRC)薄板加固钢筋混凝土(RC)梁二次受荷的力学性能,以1根对比梁和5根以初始应力为变化参数的加固梁作为研究对象,进行基于磷酸钾镁水泥(MPC)界面剂粘贴TRC预制薄板加固RC梁的正截面抗弯强度试验研究,并分析其对加固梁的力学性能、破坏特征及裂缝开展情况的影响。结果表明:TRC薄板与RC梁有着较好的界面黏结性能;TRC薄板的应变滞后现象随着梁初始应力的提高而愈加明显,RC梁的极限荷载和截面刚度也随之减小;TRC薄板能改善RC梁裂缝形式,破坏时薄板裂缝呈现"细而密"的特点;对于损伤程度较小的RC梁,其加固效果较好;临近钢筋屈服的RC梁即使卸载加固,其承载力亦提高有限。

EXPERIMENTAL RESEARCH ON SECONDARY BENDING BEHAVIOR OF REINFORCED CONCRETE BEAMS STRENGTHENED WITH TEXTILE REINFORCED CONCRETE SHEETS

In order to study the actual stress mechanical properties of RC beam strengthened with TRC sheets,one RC beam and five reinforcing beams whose parameters were the initial stress were chosen as the research objects.Magnesium potassium phosphate materials with high temperature resistance and good interfacial bonding propertiesinorganic cementitious( MPC) were used to study the flexural strength of normal section of RC beam strengthened with TRC sheets based on MPC interface agent and to analyse the impact on the failure characteristics,development of cracks and the mechanical properties of the strengthened beams. The results showed that the precast TRC sheets and RC beams have a better interface bonding performance; strain hysteresis of TRC sheets beam became obvious with beam's initial stress increased,and the ultimate load and stiffness of RC beam decreased; prefabricated TRC thin sheets could improve the form of crack which presented fine and dense cracks on the RC beams. For the smaller injury RC beams,the reinforcement effect was better; for the RC beams nearing the yield of steels,the increase in their capacity was also limited even reinforced RC beam was unloaded.