Abstract The effects of limestone replacement fraction, limestone specific surface area and water-to-binder (W/B) ratio on the threshold chloride concentration (TCC) for steel corrosion were evaluated. XRD and SEM analyses were conducted to examine the crystalline phases and microstructure of limestone-blended cement paste, respectively. The influence of pH value of concrete pore solution on the chloride binding capability was also investigated. The results demonstrate that the chloride threshold decreases as the limestone content or the W/B ratio increases, while limestone fineness shows negligible effect. XRD analyses indicate that addition of limestone inhibits the transformation from ettringite (AFt) to monosulfate (AFm), which exhibits superior chemical binding capability for chloride ions. SEM analyses suggest that addition of 15 wt% limestone contribute to a denser microstructure. Reduction in the pH value of pore solution compromises the chloride binding capability of concrete.

中文翻译：

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添加石灰石粉对钢筋混凝土钢筋腐蚀阈值氯离子浓度的影响

摘要 评估了石灰石置换率、石灰石比表面积和水与粘合剂 (W/B) 比对钢腐蚀阈值氯化物浓度 (TCC) 的影响。进行了 XRD 和 SEM 分析，分别检查了石灰石混合水泥浆的结晶相和微观结构。还研究了混凝土孔隙溶液的 pH 值对氯离子结合能力的影响。结果表明，氯化物阈值随着石灰石含量或 W/B 比的增加而降低，而石灰石细度的影响可以忽略不计。XRD 分析表明，石灰石的添加抑制了钙矾石 (AFt) 向单硫酸盐 (AFm) 的转变，其对氯离子具有优异的化学结合能力。SEM 分析表明，添加 15 wt% 的石灰石有助于形成更致密的微观结构。孔隙溶液 pH 值的降低会损害混凝土的氯化物结合能力。