基于相似理论的海工预应力混凝土构件寿命预测

Prediction analysis of service life of marine prestressed concrete structure based on similarity theory

根据经典相似理论及海工预应力混凝土结构耐久性的主要表征量,以氯离子扩散系数为纽带建立了室内加速模拟环境试验结构与现场环境结构之间的时间相似关系。参考连云港港区氯盐侵蚀环境,设计了相应的人工气候模拟侵蚀条件;浇筑了2根与现场构件材料组成相同、结构特征相似的试验梁。对现场构件及侵蚀后的试验梁钻取混凝土粉末试样,通过快速氯离子检测方法(即RCT法)测得氯离子含量。按照Fick第二扩散定律并通过Matlab拟合得到氯离子扩散系数,并根据其时间衰减关系得到该地区对应的海洋大气区时间相似系数,实现现场服役结构耐久性寿命预测。

According to classical similarity theory prestressed concrete structures, the time similarity and the main characterization of durability of the marine relationships between trial structures of indoor accelerated simulation tests in an artificial environment and the in-situ structures in the actual environment have been established by taking chloride ion diffusion coefficients as a linkage. Considering the chlorine salt corrosion environmental conditions in the Lianyungang port, the design of the homologous system of corrosion for artificial climate modeling is made. Simultaneously, two experimental beams with the same composition of materials and similar structural features are poured. And then a sample of concrete powder which is taken from the beams placed in the artificial climate modeling laboratory and in the Lianyungang port area is used for examination and tests on the concentration of the chloride ion by use of a rapid chloride ion detection method （ i. e a RCT method）. On the basis of the Fick＇s second law of diffusion, the diffusion coefficients of the chloride ion are fitted by a software Matlab. The corresponding time similarity coefficients A, under the marine atmosphere are calculated. This method can provide the basis for prediction of the service life of the marine prestressed concrete structures and make a key step for engineering applications in the future.