带横向荷载裂缝钢筋混凝土梁的钢筋锈蚀形态研究

Corrosion pattern of rebar in RC beam with loading transverse cracks

对荷载作用下恒电流通电锈蚀的带荷载裂缝钢筋混凝土梁进行研究,绘制通电锈蚀前后横向裂缝和顺筋锈胀裂缝分布图,探究横向荷载裂缝对通电锈蚀过程及锈胀裂缝开展的影响。通过三维激光扫描对锈蚀钢筋表面特征进行分析,对比通电锈蚀和自然锈蚀条件下钢筋锈蚀的纵向不均匀性和锈胀裂缝发展。研究发现,通电锈蚀和自然锈蚀下,横向裂缝的存在都会加速该处钢筋的锈蚀截面损失,但通电锈蚀下横向裂缝处的钢筋会出现明显的"颈缩"现象。钢筋截面周长锈蚀率和截面锈蚀率的分布规律相同,截面周长锈蚀率同样可以较好地反映钢筋锈蚀程度。通电锈蚀和自然锈蚀钢筋的平均截面面积与最小截面面积的比值能反映钢筋锈蚀的不均匀性,其值满足Gumbel分布。

In this paper,a reinforced concrete beam with loading cracks was studied under the action of electrified corrosion with constant current.The distributions of transverse cracks,rust expansion and reinforcement cracks were drawn before and after electrified corrosion,and the influence of transverse loading cracks on the process of electrified corrosion and expansion of cracks was explored.The surface characteristics of corroded steel bar were analyzed by three-dimensional laser scanning.The longitudinal inhomogeneity of reinforcement corrosion,the development of corrosion and expansion cracks were compared under the condition of electrified corrosion and natural corrosion. Results indicate that the existence of transverse cracks accelerate the corrosion section loss of steel bar at transverse cracks,but a significant necking phenomenon at the transverse cracks under electrified corrosion can be observed.The distribution of section corrosion ratio and circumference corrosion ratio is the same,and the circumference corrosion ratio can also reflect the degree of corrosion of steel bar.The ratio of average cross-section area to minimum crosssection area of the corroded rebar under natural and accelerated corrosion can reflect the inhomogeneity of rebar corrosion,and its value satisfies the Gumbel distribution.