The problematic expansive soils are spread in many countries and require significant improvement. The impacts of nanosilica and the Electric Arc Furnace (EAF) slag on the improvement of the swelling potential, volume changes, and Unconfined Compressive Strength (UCS) of the expansive clay samples were experimentally investigated in this study. In addition, the durability of the stabilizers against adverse effects of consecutive freeze-thaw cycles was also assessed using macro and micro tests. The results showed that the expansibility of the soil samples improved by 20% of the EAF slag and 0.5% of nanosilica decreased by 77.5% after one day of curing. To evaluate the durability of the samples, the number of freeze-thaw cycles was repeatedly increased until the dynamic equilibrium was reached. Then, the volume and water content changes and also the strength reduction rate of the treated and untreated samples were measured at the end of each cycle. The results revealed that the dynamic equilibrium for both untreated and treated samples was recorded during the 2nd to 4th cycles. The highest strength reduction rate occurred after the 1st and 2nd cycle and it was respectively 29% and 36% for the untreated and only 14% and 18% for the treated samples by the optimal amount of the EAF slag and nanosilica after 7 days of curing. However, the strength reduction rate decreased to 5.4% and 6.4% after 28 days of curing, thus curing time brought the significant improvement and promising results for the treated samples against the freeze-thaw cycles. In addition, the maximum volumetric strain was measured as 6% for the untreated expansive clay, occurring after the 4th freezing cycle. However, this value decreased significantly to 2.75%, occurring after the 3rd freezing period, for the sample improved by nanosilica and the EAF slag simultaneously. Thus, the results confirmed the strong potential use of the mixture of the EAF slag and nanosilica in reducing the negative effects of freeze-thaw cycles on the soil characteristics. Finally, to identify the underlying improvement mechanisms, the microstructural analyses were also carried out on different soil samples by using the X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) tests.

有问题的膨胀土壤遍布许多国家，需要大幅度改善。本研究通过实验研究了纳米二氧化硅和电弧炉炉渣（EAF）对膨胀粘土样品的溶胀潜力，体积变化和无侧限抗压强度（UCS）改善的影响。此外，还使用宏观和微观测试评估了稳定剂对连续冻融循环不利影响的耐久性。结果表明，养护一天后，土壤样品的膨胀性提高了20％的电弧炉渣，而0.5％的纳米二氧化硅降低了77.5％。为了评估样品的耐久性，反复增加冻融循环的次数，直到达到动态平衡。然后，在每个循环结束时，测量处理后和未处理样品的体积和水含量变化以及强度降低率。结果表明，在第2至第4个循环中记录了未处理和已处理样品的动态平衡。最佳强度降低率出现在第一个和第二个循环之后，在经过7天的固化后，通过最佳量的EAF炉渣和纳米二氧化硅，未处理样品的强度降低率分别为29％和36％，处理后的样品仅为14％和18％ 。但是，固化28天后强度降低率分别降低到5.4％和6.4％，因此固化时间对处理后的样品进行了冻融循环，带来了显着的改善和令人鼓舞的结果。此外，未经处理的膨胀土的最大体积应变为6％，发生在第四个冷冻周期之后。但是，对于同时被纳米二氧化硅和EAF熔渣改良的样品，该值在第三个冷冻期后显着降低至2.75％。因此，结果证实了EAF炉渣和纳米二氧化硅的混合物在减少冻融循环对土壤特性的负面影响方面具有强大的潜力。最后，为了确定潜在的改善机制，还使用X射线衍射（XRD）和扫描电子显微镜（SEM）对不同的土壤样品进行了微结构分析。结果证实了电炉渣和纳米二氧化硅的混合物在减少冻融循环对土壤特性的负面影响方面具有强大的潜在用途。最后，为了确定潜在的改善机制，还使用X射线衍射（XRD）和扫描电子显微镜（SEM）对不同的土壤样品进行了微结构分析。结果证实了电炉渣和纳米二氧化硅的混合物在减少冻融循环对土壤特性的负面影响方面具有强大的潜在用途。最后，为了确定潜在的改善机制，还使用X射线衍射（XRD）和扫描电子显微镜（SEM）对不同的土壤样品进行了微结构分析。