This paper investigates the free chloride profiles, diffusion parameters and chloride binding capacity of an alkali activated concrete (AACM) together with a control Portland cement (PC) concrete. Ggbs based AACM concrete specimens with different molarity of activator were exposed to a 5% NaCl solution for 540days to determine their free chloride diffusion properties. The relationships between the free and bound chloride concentration were determined by applying Freundlich and Langmuir isotherms. The required cover to steel reinforcement for corrosion prevention is derived to satisfy the limiting thresholds of free and bound chloride concentrations.

The results show that Fick's second law of diffusion applies to the free chloride profiles of AACM concrete and provides higher values of diffusion coefficients than a similar grade of PC concrete. The relationship between the free and bound chlorides is defined by the Langmuir isotherm. PC concrete has higher chloride binding capacity than AACM concrete for both water and acid soluble chlorides. Less concrete cover to steel reinforcement is required in AACM than PC concrete when calculated by using the bound chloride concentration threshold limit. The values of cover based on the corresponding free chloride limit in AACM concrete are higher than its bound chloride values.

本文研究了碱性活化混凝土（AACM）和对照波特兰水泥（PC）混凝土的游离氯剖面，扩散参数和氯离子结合能力。将具有不同摩尔浓度活化剂的Ggbs基AACM混凝土样品暴露于5％NaCl溶液中540天，以确定其游离氯的扩散特性。通过应用Freundlich和Langmuir等温线确定游离和结合氯离子浓度之间的关系。得出了用于防止腐蚀的钢筋补强所需要的覆盖层，以满足游离和结合氯化物浓度的极限阈值。

结果表明，菲克第二扩散定律适用于AACM混凝土的游离氯剖面，并且比类似等级的PC混凝土具有更高的扩散系数值。游离氯化物和结合氯化物之间的关系由Langmuir等温线定义。相对于AACM混凝土，PC混凝土对水和酸溶性氯化物的氯化物粘结能力更高。通过使用束缚氯化物浓度阈值限值进行计算，AACM所需的钢筋混凝土保护层少于PC混凝土。基于AACM混凝土中相应的游离氯化物限量的覆盖值高于其结合氯化物值。