Abstract The action of added sodium sulfate (Na2SO4) leading to increased reactivity and early strength in slag: cement binders remains unclear. In this study, early hydration reactions and resultant compressive strength in a 50:50 slag:cement binder in the presence of Na2SO4 were investigated. Early strength increases in the presence of Na2SO4 were shown to be due to a combination of increased alite hydration and increased slag dissolution. Increased alite hydration was due to neither reduced dissolved Al concentration nor increased alite under-saturation but related to increased ionic strength. Increased slag dissolution was associated with both increased pH and decreased Ca activity with the two being connected through the portlandite solubility limit. Na2SO4 was shown to substantially enhance slag dissolution at fixed pH 13 with this action attributed to greater under-saturation of slag as a result of ettringite formation. Na2SO4 was shown to be superior to alternate activators in a slag:cement binder.

中文翻译：

---

硫酸钠在矿渣水泥混合物中促进早期水化的机制——来自孔隙溶液化学的见解

摘要 添加硫酸钠 (Na2SO4) 导致矿渣反应性和早期强度增加的作用：水泥粘合剂尚不清楚。在这项研究中，研究了在存在 Na2SO4 的情况下，在 50:50 矿渣:水泥粘合剂中的早期水化反应和由此产生的抗压强度。在 Na2SO4 存在下早期强度的增加被证明是由于阿利特水化增加和炉渣溶解增加的组合。alite 水合增加的原因既不是溶解的 Al 浓度降低也不是 alite 欠饱和度增加，而是与离子强度增加有关。矿渣溶解增加与 pH 值升高和 Ca 活性降低有关，两者通过硅酸盐溶解度极限相连。在固定的 pH 值 13 下，Na2SO4 显示出显着增强炉渣溶解，这种作用归因于钙矾石形成导致炉渣更不饱和。Na2SO4 被证明在矿渣：水泥粘合剂中优于替代活化剂。