Abstract The aim of this study is to investigate systematically the chloride diffusivity and chloride threshold of a wide range of calcium-rich and fly ash-dominated alkali-activated samples in light of their compositional differences. To this end, the effects of various fly ash (FA)-to-slag ratios, of alkali concentrations and of silicate content in the activator were investigated. The electrochemical aspects of the passive samples were also assessed. Results show the prominent role of calcium in the matrix to reduce the chloride diffusivity. While higher alkali concentration increased the porosity and chloride diffusivities in general, lower modulus ratios provided considerably better performance in the FA-dominated samples. Chloride threshold values range between 0.19 (wt% binder mass) for calcium-rich mortars fabricated at low levels of alkalinities and 0.69 for FA-dominated mortars fabricated with highly alkaline activators. Half-cell potential and polarization resistance of alkali-activated samples were in general lower than their Portland cement counterparts.

中文翻译：

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增强碱激活砂浆中的氯化物扩散率、氯化物阈值和腐蚀开始：钙、碱和硅酸盐含量的作用

摘要 本研究的目的是系统地研究各种富含钙和以粉煤灰为主的碱活化样品的氯化物扩散率和氯化物阈值，根据它们的成分差异。为此，研究了各种粉煤灰 (FA) 与炉渣的比率、碱浓度和活化剂中硅酸盐含量的影响。还评估了被动样品的电化学方面。结果表明钙在基质中对降低氯化物扩散率的重要作用。虽然较高的碱浓度通常会增加孔隙率和氯化物扩散率，但较低的模量比在以 FA 为主的样品中提供了相当好的性能。氯化物阈值范围在 0 之间。对于在低碱度水平下制造的富钙砂浆为 19（重量百分比粘合剂质量），对于使用高碱性活化剂制造的以 FA 为主的砂浆为 0.69。碱活化样品的半电池电位和极化电阻通常低于其对应的波特兰水泥。