受荷混凝土中钢筋锈蚀速率计算方法

为研究荷载对钢筋锈蚀速率及结构耐久性的影响,在潮汐区与盐雾区开展不同荷载条件下氯离子扩散试验,荷载大小分别为无荷载、0.3倍和0.5倍混凝土抗折强度.在混凝土中掺入氯盐,开展不同浓度氯盐条件下的钢筋锈蚀试验.通过氯离子扩散试验得到荷载对氯离子扩散影响系数与荷载大小的关系,修正菲克第二定律中的氯离子扩散系数.钢筋锈蚀试验中测试不同时间下混凝土构件中钢筋的锈蚀电流密度,拟合出钢筋锈蚀电流密度与氯盐浓度和锈蚀时间之间的关系.结合混凝土中考虑荷载影响的氯离子扩散模型与钢筋锈蚀模型,给出荷载作用下混凝土中钢筋锈蚀速率的计算方法.该方法对于海洋环境中荷载作用下钢筋混凝土结构耐久性寿命计算具有重要意义.

Calculation of concrete steel corrosion rate under the action of load

To explore the effects of load on steel corrosion rate and structural durability, Chloride diffusion experiments under various load conditions were carried out in tidal zone and salt spray zone. The load sizes were 0 times, 0. 3 times, 0. 5 times the flexural strength. The steel corrosion experiments were conducted in concretes mixed with different concentrations of sodium chloride. The results of chloride diffusion experiments showed the relationship between chloride diffusion load coefficient and the load sizes. This could be applied to determine the chloride diffusion coeffients in Fick's second law. The current density of steel corrosion as a function of time were measured in steel corrosion experiments. A model could be be fitted to represent the relationship among the current density, chloride content and time could. The steel corrosion rate in concretes under the action of load could be calculated by pluging the chloride diffusion model and considering loading factor into the steel corrosion model. This method is important to calculate reinforced concrete structure durability under the action of load in marine environment.