| 摘要: |
| 研究了轴压应力对钢筋锈蚀导致混凝土保护层胀裂历程的影响。采用DIANA软件构建了保护层受钢筋非均匀锈胀作用的三维仿真模型，建立了在轴压作用下，受围压约束裸筋与混凝土内钢筋横向变形等效的方法，有效解决了对混凝土柱同时施加轴压和非均匀锈胀作用的难题。在此基础上，对不同负载水平和配筋方式的24根轴压柱的锈胀开裂历程进行了数值分析，探讨了轴压应力大小对锈胀裂缝扩展和胀裂各阶段特征锈蚀率的影响规律，并分析了轴压应力水平与混凝土强度、相对保护层厚度等其他锈胀开裂影响因素间的相关性。结果表明：轴压应力的存在改变了混凝土构件锈胀裂缝的发展趋势，影响了保护层锈胀开裂各阶段的钢筋锈蚀率；构件内多根钢筋锈蚀导致保护层破损的形态及其发生整体剥落的可能性受轴压应力水平影响显著，相同条件下随轴压应力增大，保护层发生整体剥落的可能性大大增加；钢筋非均匀锈蚀比均匀锈蚀更容易使保护层胀裂，且两者间的差异随轴压应力水平增加而加大；施加轴压应力不会改变混凝土强度和相对保护层厚度对锈胀裂缝发展的影响规律。 |
| 关键词: 轴压作用 钢筋混凝土柱 负载 锈蚀 保护层 |
| DOI： |
| 分类号:TU375 |
| 基金项目:国家自然科学基金资助项目（51109121，51379111） |
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| Influence mechanism of axial compression on corrosion-induced concrete cover cracking |
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WANG Qing1,2, WEI Ze-zhong1, XU Gang1,2, WANG Yi-ming1
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1.College of Civil Engineering & Architecture, China Three Gorges University, Yichang;2.Collaborative Innovation Center for Geo-Hazards and Eco-Environment in Three Gorges Area, Hubei Province, Yichang
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| Abstract: |
| Influences of an axial compressive stress on the concrete cover expansion cracking process caused by reinforcement corrosion was studied. A three-dimension numerical simulation model for cover cracking affected by non-uniform corrosion expansion of a reinforcement concrete column was developed by DIANA, the equivalent method for lateral deformation of the reinforcement by confining pressure constraint and reinforcement in concrete by the action of axial compression was established, the problems concerning concrete columns imposed by the axial pressure and non-uniform corrosion effects were solved simultaneously. On this basis, the corrosive cracking process of 24 axial compression columns under different load levels and a reinforcement method were analyzed by simulation; the influence law of a characteristic corrosion rate of the axial compression stress to corrosive crack extension and expansion of crack characteristics in each stage was discussed; the relationships between the axial compressive stress levels and the strength of concrete, the relative thickness of the concrete cover and other corrosive cracking influence factors were analyzed. The analysis results show that the development trend of the corrosive cracks of the concrete members was changed by the existence of the axial compressive stress, and the rebar corrosion rates of the cover expansion cracking in different stages were affected by this stress. The failure form of the cover was caused by a multiple reinforcement corrosion in the component and the possibility of its overall spalling was influenced by the axial compressive stress level significantly. Under the same conditions, with the increase of axial compressive stresses, the possibility of the spalling of the concrete protective cover greatly increased. And the protective cover cracking overall spalled by the non-uniform corrosion of the reinforcement was easier than that of the uniform corrosion, and the differences between both conditions increased with the increase of the axial compression stress level. The influences of the concrete strength and the relative protective cover thickness on the development of the corrosive cracking law will not be imposed by the changes in the axial compression stress. |
| Key words: axial compression reinforced concrete column load condition corrosion protective cover |
