In regions where the concrete structures are exposed to a salty environment, the concrete requires high resistance to chloride-ion penetration. To achieve higher resistance against chloride ingress, a pozzolanic admixture incorporating a high volume of SiO2 and Al2O3 has been developed. The admixture is a fine mineral powder with a specific surface area of 13,000 m2/kg or higher. It is typically mixed with the concrete at a cement replacement level of 5–13 mass% (20–40 kg/m3). To demonstrate the applicability of the admixture to general ready-mix concretes, this study examined the fundamental properties of concrete cured under standard conditions regarding resistance against chloride ingress. Chloride immersion tests revealed high resistance against penetration of concrete produced with the admixture. Pore-size distribution analysis confirmed that the volume of pores less than 0.01 μm diameter increased whereas a decrease of large pores occurred (0.1 μm diameter or larger). The major contributor to the high resistance was found to be the immobilization of penetrating chloride ions by the formation of Friedel’s salt.

中文翻译：

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用含有丰富 SiO2 和 Al2O3 的外加剂制成的标准固化混凝土的抗氯化物侵入性能

在混凝土结构暴露于含盐环境的地区，混凝土需要高度抵抗氯离子渗透。为了提高对氯化物侵入的抵抗力，已开发出一种含有大量 SiO2 和 Al2O3 的火山灰混合物。外加剂是比表面积为 13,000 m2/kg 或更高的精细矿物粉末。它通常以 5–13 质量% (20–40 kg/m3) 的水泥替代水平与混凝土混合。为了证明外加剂对一般预拌混凝土的适用性，本研究检查了在标准条件下固化的混凝土的基本特性，以防止氯化物进入。氯化物浸泡试验表明，该外加剂生产的混凝土具有很高的抗渗透性。孔径分布分析证实，直径小于 0.01 μm 的孔体积增加，而大孔（直径 0.1 μm 或更大）的体积减少。发现高电阻的主要贡献者是通过形成弗里德尔盐固定渗透的氯离子。