氯盐侵蚀环境下圆形截面混凝土构件服役寿命 分析与配合比选择

氯离子侵蚀混凝土结构,导致混凝土过早发生破坏,其原因之一是在进行结构满足耐久性设计时忽略了结构的外形和扩散维数对氯离子扩散的影响。基于钢筋脱钝的临界氯离子浓度,提出了圆形截面氯离子侵蚀的耐久性服役寿命计算方法。开展了耐久性正交实验,通过服役寿命定量计算,可以对圆形截面构件混凝土的配合比进行设计与选择。通过算例分析混凝土构件的服役寿命,结果表明圆形截面构件相对于矩形截面构件具有更好的耐久性,在混凝土结构耐久性设计时,采用圆形截面构件可以增加满足耐久性的混凝土配合比方案,减小混凝土配置难度,降低建造成本。

STUDY OF SERVICE LIFE AND SELECTION OF MIX RATIO FOR CONCRETE COMPONENT WITH CIRCULAR SECTION BASED ON CRITICAL CHLORIDE ION

The concrete structure under chloride ion is destroyed prematurely because of the lack of durability. The reason is that the influence of structure shape and diffusion dimension on chloride ion diffusion is neglected when the structure meets the durability design. The method for calculating the durability service life of circular section under chloride ion erosion is proposed based on the critical chloride ion concentration. The orthogonal test of durability is carried out and the concrete mix ratio of circular section members can be selected by quantitative calculation of service life. Furthermore, efforts are made through giving examples in analysis of the distribution rule of chlorine ion contained in the circular section members. The results show that circular section members have better durability than rectangular section members. Therefore, it concludes that the circular section member is more durable than rectangular section member. The circular section members can increase the concrete mix ratio to meet the durability, reduce the difficulty of concrete configuration and reduce the construction cost.