工业废渣复合固化黄土强度特性及影响因素研究

工业废渣配合水泥用于土体固化能有效增加土体强度,提高废渣利用率,具有明显的经济效益和环保效益。将粉煤灰-脱硫石膏-水泥三元凝胶体系运用于黄土固化,使用CaOH₂和NaOH作为活性激发剂形成复合黄土固化剂,通过正交试验以无侧限抗压强度为标准判断固化剂各组分对强度的影响程度,并选取最优掺入比。使用最优掺入比研究了黄土含水率、水灰比和早强剂对复合固化黄土强度的影响,并与水泥黄土进行比较。结果表明:复合固化黄土中后期强度增长率高,90 d强度达到6.85 MPa,相当于20%水泥掺入比的水泥黄土90 d的强度;复合固化黄土的含水率在20%左右时各龄期强度最高。三乙醇胺和水玻璃可用作复合固化黄土早强剂。XRD衍射图谱和SEM微观结构印证了复合固化黄土固化原理和强度规律。

Loess Solidified by Industrial Waste Residue Composite Curing Agent: Strength Performance and Influential Factors

Industrial waste residue combined with cement is of remarkable economic and environmental benefits in solidifying soil by enhancing soil strength and improving residue utilization. A ternary gel system composing fly ash, desulfurized gypsum, and cement is applied to solidify loess in this research. CaOH₂ and NaOH are selected as activators of the composite curing agent. Through orthogonal experiments, the influence degree of each component of the composite curing agent on unconfined compressive strength is examined, and the optimum mixing ratio is determined. On this basis, the impacts of loess water content, water-cement ratio, and early strength agent on the strength of the solidified loess are investigated and compared with those of cement-improved loess. Result shows that the strength growth rate solidified by the composite curing agent in middle and late age is higher than that of cement-improved loess, with the 90 day strength amounting to 6.85 MPa, equivalent to that of cement-improved loess with 20% cement mixing ratio. When the water content of composite solidified loess is about 20%, the strength reaches to the maximum at all ages. Triethanolamine and sodium silicate can be used as early strength agent for the composite solidified loess. In addition, XRD diffraction pattern and SEM microstructure verified the curing principle and strength law.