Steel slag (SS) exhibits low hydration activities and expansive phases, which should be pretreated prior to using as binding materials. Thus, these properties of SS were improved through a combined treatment of alkali and then wet carbonation (A_C) in this study. Effect of sodium silicate modulus (M = 1.0–2.5) and carbonation temperature (50–200 °C) on cementitious property of SS was investigated. Results showed that the optimum modulus and temperature were 2.0 and 150 °C under single alkali and single carbonation treatment of SS, respectively. In case of combined treatment, the optimal modulus was 2.0 with an optimum temperature of 100 °C (A2.0_C100°C-SS). The 28 d compressive strength increased by 27.1% and expansion rate decreased by 17.7% of A2.0_C100°C-SS-PC compared to untreated SS-PC. This was attribute to the fact that the newly formed CaCO with micro-nano size and high activity existed in A_C-SS can react with Al-containing minerals in OPC to form monocarboaluminate, and Si-gels produced during carbonation can react with CH to form C-S-H phases. The early hydration activity of OPC was more obviously improved by adding A_C-SS compared to adding A_SS or C_SS. This was due to the micro-nano size effect of CaCO and Si-gels can provide nucleation sites for C-S-H formation. Alkali pretreatment can improve the SS carbonation, reaching the maximum carbonation degree of 53% at 100 °C compared to carbonation alone (47% at 150 °C). The embodied CO index of A2.0_C100-SS-OPC system decreased to 9.843 compared to OPC (10.511), indicating that the A_C treatment for SS was a more sustainable and environmentally friendly method.

中文翻译：

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粘结材料用钢渣的碱活化碳化预处理

钢渣（SS）具有低水化活性和膨胀相，在用作粘结材料之前应进行预处理。因此，在本研究中，通过碱处理和湿碳酸化 (A_C) 的联合处理，SS 的这些性能得到了改善。研究了水玻璃模量（M = 1.0–2.5）和碳化温度（50–200 °C）对SS胶凝性能的影响。结果表明，单一碱处理和单一碳化处理SS的最佳模量和温度分别为2.0和150℃。在联合处理的情况下，最佳模量为2.0，最佳温度为100℃(A2.0_C100℃-SS)。与未处理的SS-PC相比，A2.0_C100°C-SS-PC的28天抗压强度提高了27.1%，膨胀率降低了17.7%。这是由于A_C-SS中新形成的微纳尺寸、高活性的CaCO可以与OPC中的含Al矿物反应生成单碳铝酸盐，而碳酸化过程中产生的Si-gel可以与CH反应生成碳铝酸盐。 CSH 阶段。与添加A_SS或C_SS相比，添加A_C-SS对OPC的早期水化活性有更明显的提高。这是由于 CaCO 和 Si-gel 的微纳米尺寸效应可以为 CSH 的形成提供成核位点。碱预处理可以改善SS碳酸化，与单独碳酸化（150℃时47％）相比，在100℃时达到最大碳酸化度53％。与OPC（10.511）相比，A2.0_C100-SS-OPC体系的CO含量指数下降至9.843，表明A_C处理SS是一种更可持续、更环保的方法。