锈蚀钢筋轴向拉伸疲劳试验研究

Axial Tensile Fatigue Properties of Artificially Corroded Steel Bars

采用通电加速锈蚀的方法获取锈蚀钢筋,并从中选取17根锈蚀率不同的钢筋试件进行轴向拉伸疲劳试验,以研究应力幅与锈蚀率对钢筋疲劳寿命以及疲劳锈损后力学性能的影响.钢筋试件按近似平均锈蚀率0%,3%,6%,9%,12%,15%设计.结果表明:实测锈蚀率为3.87%,6.78%,9.47%,12.32%,15.35%的钢筋疲劳寿命较未锈蚀钢筋疲劳寿命分别降低了51.26%,60.84%,65.82%,71.04%,79.22%;应力幅200MPa时,应力比为0.24,0.34钢筋的疲劳寿命分别较应力比为0.10时降低了8.6%,13.6%;钢筋的疲劳寿命近似按指数规律衰减.

The method of impressed current accelerating corrosion was employed to obtain corroded steel bars and then the corroded steel bars were used in axial tensile fatigue testing.The impact of corrosion rate on the fatigue life of corroded steel bars and mechanical properties after steel bars being corroded were observed.Two uncorroded reinforcement specimens and fifteen corroded reinforcement specimens were tested under constant amplitude axial tensile fatigue loading.For convenience,the specimens were divided into six groups with reinforcement of average corrosion rates approximately at 0%,3%,6%,9%,12% and15%.The results show as follows：The fatigue life of steel bars is obviously reduced as the result of reinforcement corrosion;a logarithmic linear relation exists between the stress magnitude and the fatigue life of the reinforcement specimens of different corrosion rates.Compared with uncorroded specimens,the fatigue life of corroded specimens drops about 51.26%,60.84%,65.82%,71.04%and 79.22%respectively,corresponding to tested corrosion rates of 3.87%,6.78%,9.47%,12.32%and 15.35%;when stress amplitude is 200 MPa,the fatigue life of steel bars at stress ratio of 0.24 and 0.34 is reduced by 8.6%and13.6% compared with that of steel bars at stress ratio of 0.10.The fatigue life of corroded steel bars attenuates with the development of corrosion by the exponential law approximately.