Abstract In the present study, industrial wastes such as Granulated Blast Furnace Slag (GBFS) and Basic Oxygen Furnace Slag (BOFS) activated with calcium oxide (CaO) and medium reactive magnesia (MgO) are used for chemical stabilization of a soft clay. This environmentally friendly approach can eliminate the hazards associated with improper waste disposal and reduce greenhouse gas emissions generated by cement production. To this end, various amounts of additives (ranging from 2.5 to 20%) with the activator:slag ratio of 1:3 are added to kaolinite clay and cured at two temperatures of 20 and 45°C. A series of laboratory tests, including pH, Electrical Conductivity (EC), one-dimensional consolidation, Unconfined Compressive Strength (UCS), are conducted on the stabilized samples. The increasing temperature causes a faster formation of cementitious products and a higher UCS value, as confirmed by the SEM micrographs and XRD analysis, particularly in the case of MgO-BOFS (MB) and CaO-BOFS (CB) samples with the UCS values of 4 and 4.7 MPa after 90 days of curing, respectively. Furthermore, the MB- and CB-stabilized clay samples show a better compressibility characteristic compared to the MgO-GBFS (MG) and CaO-GBFS (CG) blends. To further enhance the activity of the additives and to prepare a slag-clay based geopolymers, two types of alkaline solutions at various Na2SiO3:NaOH ratios are added to the mixtures at the final step. In addition, the energy absorption capacity (Eu) and the secant modulus (E50) of the optimum blends are determined to assess the toughness and stiffness of the samples. The results indicate that the UCS values of the MB and CB samples increase up to 7.41 MPa and 8.44 MPa after 90 days of curing, respectively, when the Na2SiO3:NaOH ratio is 80:20. Generally, the use of slag-clay based geopolymers, particularly BOFS, is very effective to address the problems associated with the soft soil and the optimum mixtures are successful in decreasing settlements and enhancing compressive strength of the soft soil, which can be considered for use as a pavement base material.

中文翻译：

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矿渣基混合物和地质聚合物稳定的软粘土的力学和压缩特性

摘要 在本研究中，使用氧化钙 (CaO) 和中等活性氧化镁 (MgO) 活化的颗粒状高炉渣 (GBFS) 和碱性氧气炉渣 (BOFS) 等工业废物对软粘土进行化学稳定。这种环保方法可以消除与废物处理不当相关的危害，并减少水泥生产产生的温室气体排放。为此，将不同数量的添加剂（范围为 2.5 至 20%）以 1:3 的活化剂：炉渣比例添加到高岭土中，并在 20 和 45°C 的两个温度下固化。对稳定后的样品进行了一系列实验室测试，包括pH、电导率（EC）、一维固结、无侧限抗压强度（UCS）。SEM 显微照片和 XRD 分析证实，温度升高会导致胶结产品更快形成和更高的 UCS 值，特别是在 MgO-BOFS (MB) 和 CaO-BOFS (CB) 样品的情况下，UCS 值为固化 90 天后分别为 4 和 4.7 MPa。此外，与 MgO-GBFS (MG) 和 CaO-GBFS (CG) 混合物相比，MB 和 CB 稳定的粘土样品显示出更好的压缩特性。为了进一步提高添加剂的活性并制备基于矿渣粘土的地质聚合物，在最后一步将两种不同 Na2SiO3:NaOH 比例的碱性溶液添加到混合物中。此外，确定最佳共混物的能量吸收能力 (Eu) 和割线模量 (E50) 以评估样品的韧性和刚度。结果表明，当 Na2SiO3:NaOH 比例为 80:20 时，MB 和 CB 样品的 UCS 值在固化 90 天后分别增加到 7.41 MPa 和 8.44 MPa。一般来说，使用矿渣粘土基地质聚合物，特别是 BOFS，对于解决软土相关问题非常有效，并且最佳混合物成功地减少了软土的沉降和提高了抗压强度，可以考虑使用作为路面基层材料。