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为了研究硝酸腐蚀条件下T型混凝土梁抗弯性能的变化规律,采用p H值为4.5的硝酸溶液对4根相同的T型混凝土梁分别浸泡20,40,60,80 d,然后对标准试验梁和腐蚀试验梁进行受弯试验。研究在不同硝酸腐蚀时间下的试验现象、开裂荷载和极限荷载、抗弯刚度和钢筋应变。结果表明:经过不同时间硝酸溶液腐蚀后的T型混凝土梁的受弯破坏仍为适筋梁弯曲破坏;随着硝酸腐蚀时间的增长,T型混凝土梁的开裂荷载减小,极限荷载明显下降,但达到一定程度后不再出现大变化;在弹性阶段,跨中位移增长缓慢且曲线大致呈线性关系,在屈服阶段,腐蚀时间越长,试验梁的位移突变的荷载越小,试验梁破坏时的最大挠度越大,即抗弯刚度越小。采用最小二乘法拟合出硝酸腐蚀下T型混凝土梁承载力衰减模型,其衰减函数大致符合指数函数的变化规律。
In order to study the variation of flexural behavior of T-shaped concrete beams under nitric acid corrosion, four identical T-shaped concrete beams were soaked for 20, 40, 60 and 80 d respectively with nitric acid solution with pH 4.5, and then the standard test beam and Corrosion test beam Bending test. The test phenomenon under different nitric acid corrosion time, cracking load and ultimate load, flexural rigidity and steel strain were studied. The results show that the flexural failure of T-shaped concrete beams after being corroded by nitric acid solution at different times is still the bending failure of the proper reinforcement beams. With the increase of nitric acid corrosion time, the cracking load of T-shaped concrete beams decreases and the ultimate load declines obviously, However, after reaching a certain level, there is no big change any more. During the elastic phase, the mid-span shift grows slowly and the curve is roughly linear. During the yielding phase, the longer the corrosion time is, the smaller the load of the test beam is. The greater the maximum deflection, the smaller the bending stiffness. The least squares method was used to fit the attenuation model of bearing capacity of T-shaped concrete beams under the corrosion of nitric acid. The attenuation function of the T-shaped concrete beam roughly accorded with the changing law of exponential function.