Lian Fengmei, Du Chuanyang, Meng Dan
College of Architecture and Transportation, Liaoning Technical University, Fuxin 123000, China.
School of Civil Engineering, Liaoning Technical University, Fuxin 123000, China.
Materials (Basel). 2023 Jun 25;16(13):4593. doi: 10.3390/ma16134593.
Our research group prepared a new filling paste consisting of steel slag-oil shale residue and no admixtures. It was used as the research object to explore the combined effect of chloride and dry-wet cycling-driven erosion on the long-term stability of a cemented filling paste made of total solid wastes. Macroscopic experiments and microscopic analyses methods were employed. The influence of solutions with different mass fractions of chloride salts and different cycling periods on the uniaxial compressive strength and toxicity of the steel slag-oil shale residue-based filling paste was studied, and the deterioration mechanisms of the steel slag-oil shale residue-based filling paste under combined erosion from chloride and dry-wet cycling were investigated. The test results showed that in the same cycling conditions, the strength of the steel slag-oil shale residue-based filling paste increased first with the increase in the mass fraction of the chloride solution and then decreased with the increase in the mass fraction of the chloride solution after reaching the peak value; the leached concentrations of heavy metal ions decreased with increasing chloride salt mass fraction. With an increase in the number of dry-wet cycles, the compressive strength of the specimens in the chloride salt solution with a mass fraction of 0 (pure water) first increases and then tends to be stable. The strength of samples in 5% and 10% chloride salt solutions increased first and then decreased with an increase in the number of dry-wet cycles. The leached concentrations of heavy metal ions from the samples in all three solutions first decreased and then stabilized. The prehydration products of the steel slag-oil shale residue-based filling paste were C-S-H gels, AFt and Friedel's salt, and these increased with increasing chloride salt mass fraction and the number of dry-wet cycles. However, the hydration reactions of the samples in the 0% chloride solution nearly stopped in the later stages of cycling, and the samples in 5% and 10% chloride salt solutions developed local cracks due to the accumulation of hydration products. The results showed that the number of dry-wet cycles and the chloride salt mass fraction affected the strength and leaching characteristics of the steel slag-oil shale residue-based filling paste by changing the type and amount of erosion products. The test results provide a scientific basis for the promotion and application of backfilling pastes made from total solid wastes.
我们的研究小组制备了一种由钢渣-油页岩渣组成且无外加剂的新型充填膏体。以其作为研究对象，探讨氯离子和干湿循环侵蚀对全固体废弃物胶结充填膏体长期稳定性的综合影响。采用了宏观试验和微观分析方法。研究了不同质量分数氯盐溶液和不同循环周期对钢渣-油页岩渣基充填膏体单轴抗压强度和毒性的影响，并研究了钢渣-油页岩渣基充填膏体在氯离子和干湿循环联合侵蚀作用下的劣化机制。试验结果表明，在相同循环条件下，钢渣-油页岩渣基充填膏体强度随氯溶液质量分数的增加先增大，达到峰值后随氯溶液质量分数的增加而减小；重金属离子的浸出浓度随氯盐质量分数的增加而降低。随着干湿循环次数的增加，质量分数为0（纯水）的氯盐溶液中试样的抗压强度先增大后趋于稳定。5%和10%氯盐溶液中试样的强度随干湿循环次数的增加先增大后减小。三种溶液中试样重金属离子的浸出浓度均先降低后稳定。钢渣-油页岩渣基充填膏体的水化产物前期为C-S-H凝胶、AFt和Friedel盐，且随氯盐质量分数和干湿循环次数的增加而增加。然而，0%氯溶液中试样的水化反应在循环后期几乎停止，5%和10%氯盐溶液中试样因水化产物的堆积而产生局部裂缝。结果表明，干湿循环次数和氯盐质量分数通过改变侵蚀产物的类型和数量影响钢渣-油页岩渣基充填膏体的强度和浸出特性。试验结果为全固体废弃物充填膏体的推广应用提供了科学依据。
