西安建筑科技大学学报(自然科学版)

氧气作为侵蚀介质参与钢筋混凝土结构的锈蚀破坏过程,因此,氧气扩散系数是结构耐久性预测模型的必要参数.针对实际服役中的混凝土结构,研究疲劳损伤混凝土氧气扩散系数与损伤变量的关系.研究结果表明:随着混凝土疲劳损伤度增加,小孔径孔隙比例先增后减; 混凝土氧气扩散系数随着损伤度增大而增大,损伤度较大时增长速率较快; 结合多孔材料气体扩散理论,建立了混凝土氧气扩散系数与损伤度、初始孔隙率的关系式,为海洋环境下混凝土结构耐久性预测提供理论基础.

Oxygen is involved in the corrosion failure process of reinforced concrete structures as an erosion medium, so the oxygen diffusion coefficient is a necessary parameter for the prediction model of structural durability. In this paper, the relationship between oxygen diffusion coefficient and damage variable of fatigue damage concrete is studied for concrete structure in actual service. The results show that with the increase of fatigue damage degree of concrete, the proportion of small pore size increases first and then decreases. The oxygen diffusivity of concrete increases with the increase of damage degree, and the growth rate is larger at a greater damage degree. Based on the gas diffusion theory of porous materials, the function for oxygen diffusivity is established using damage degree and initial porosity, which provides a theoretical basis for predicting the durability of concrete structures in marine environment.

引言
1 试验概况
2 试验结果分析
3 结论

表1 混凝土配合比/kg·m-3<br/>Tab.1 Mix proportion of concrete/kg·m-3

表1 混凝土配合比/kg·m-3
Tab.1 Mix proportion of concrete/kg·m-3

图1 疲劳试验装置<br/>Fig.1 Device for fatigue experiment

图1 疲劳试验装置
Fig.1 Device for fatigue experiment

表2 不同试件疲劳荷载<br/>Tab.2 Fatigue load for different specimens

表2 不同试件疲劳荷载
Tab.2 Fatigue load for different specimens

图2 氧气扩散试验装置<br/>Fig.2 Test device for oxygen diffusion

图2 氧气扩散试验装置
Fig.2 Test device for oxygen diffusion

图3 核磁共振孔径分布图<br/>Fig.3 Pore size distribution measured by NMR

图3 核磁共振孔径分布图
Fig.3 Pore size distribution measured by NMR

表3 混凝土试件氧气扩散系数/(m2·s-1)<br/>Tab.3 Oxygen diffusivity of concrete specimens/(m2·s-1)

表3 混凝土试件氧气扩散系数/(m2·s-1)
Tab.3 Oxygen diffusivity of concrete specimens/(m2·s-1)

图4 不同损伤度下的混凝土氧气传输系数<br/>Fig.4 Oxygen transfer coefficients under different degrees of damage

图4 不同损伤度下的混凝土氧气传输系数
Fig.4 Oxygen transfer coefficients under different degrees of damage

图5 不同损伤度下n值拟合<br/>Fig.5 Oxygen transfer coefficients under different degrees of damage

图5 不同损伤度下n值拟合
Fig.5 Oxygen transfer coefficients under different degrees of damage

表4 混凝土氧气扩散系数试验值与计算值比较(10-8 m2/s)<br/>Tab.4 Comparison of tested and calculated oxygen diffusivity of concrete(10-8 m2/s)

表4 混凝土氧气扩散系数试验值与计算值比较(10-8 m2/s)
Tab.4 Comparison of tested and calculated oxygen diffusivity of concrete(10-8 m2/s)

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备注

引言

1 试验概况

2 试验结果分析

3 结论

期刊信息