为减少砒砂岩区土壤水土流失,实现钢渣粉和砒砂岩在实际工程中的有效利用,通过无侧限抗压、X射线衍射(XRD)、扫描电子显微镜、超景深三维显微镜和压汞等试验,探究钢渣粉掺量、碱质量分数对砒砂岩钢渣粉水泥复合土宏观力学性能及细微观结构的影响。研究结果表明:在高温碱激发作用下,钢渣粉水化生成的凝胶和铝铁钙石对复合土的增强作用低于水泥对复合土的增强作用,导致钢渣粉替代水泥掺量增加,复合土的抗压强度降低;碱激发剂增加,可促进钢渣粉水化生成产物增多,更好地起到胶结土颗粒和填充内部孔隙的作用,使复合土表面结构更均匀,内部结构更密实,抗压强度提高,碱质量分数为2%时,效果最佳。研究成果可为砒砂钢渣粉水泥复合土在工程实际应用提供理论依据。
Abstract
The study aims to reduce soil and water loss in arsenic-bearing sandstone areas and promote the effective utilization of steel slag powder and arsenic-bearing sandstone in practical engineering applications. The effects of substitution rates and alkali equivalents of steel slag powder on the macro-mechanical properties and microstructure of arsenic-bearing sandstone-steel slag powder cement composite soil were investigated using unconfined compressive strength tests, X-ray diffraction (XRD), scanning electron microscopy, high-resolution three-dimensional microscopy and mercury intrusion porosimetry tests. Results show that under high-temperature alkali excitation, the gel and ettringite generated by the hydration of steel slag powder contribute less to the enhancement of composite soil than the cement does, which leads to a reduction in compressive strength of the composite soil with increasing substitution rate of steel slag powder. Increasing the dose of alkali activator promotes the generation of hydration products from steel slag powder, making it more effective in binding soil particles and filling internal pores. This results in a more uniform surface structure and a denser internal structure of the composite soil, which enhances its compressive strength. The best effect was observed when the alkali equivalent was 2%. The results provide a theoretical basis for the practical application of arsenic-bearing sandstone-steel slag powder cement composite soil in engineering.
关键词
钢渣粉 /
抗压强度 /
碱质量分数 /
砒砂岩 /
细微观结构
Key words
steel slag powder /
compressive strength /
alkali equivalent /
Arsenic-bearing sandstone /
microstructure
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基金
国家自然科学基金项目(51869022);内蒙古自治区自然科学基金项目(2020MS05051)
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