干燥脱水过程中纤维加筋固化淤泥的强度特性

淤泥是一种天然含水率高且力学性质极差的固体废弃物,采取有效的技术方法进行快速脱水和增强可以实现淤泥资源化和高效利用。选取离散短丝聚丙烯纤维作为加筋材料,水泥和粉煤灰作为固化材料,通过开展无侧限抗压试验,研究了纤维加筋固化淤泥在干燥路径中强度的变化,并分析了干燥过程中不同目标含水率状态(分别为45%,40%,35%,30%,25%,20%,15%,10%和5%)和纤维掺量(0~0.8%)对加筋固化淤泥强度的影响机理。结果表明:①纤维的加入能有效提高固化淤泥的峰值强度和残余强度,且强度值随纤维掺量的增加呈现先上升后下降的趋势,最优纤维掺量为0.1%;②干燥脱水过程中,试样的无侧限抗压强度随含水率的减小近似于线性增加,破坏形式由塑性破坏逐渐向脆性破坏过渡,而纤维的加入可以有效抑制试样的脆性破坏,提升试样的韧性;③纤维加筋对固化淤泥强度的贡献随含水率的减小而逐渐增加,根本原因是纤维—淤泥界面作用力在低含水率条件下能得到更佳的激发。

Strength Characteristics of Fiber Reinforced Solidified Sludge During Drying

Sludge is a kind of solid waste with high natural moisture content and extremely poor mechanical properties. Adopting effective technical methods for rapid dewatering and increasing strength is an important prerequisite for realizing the utilization and efficient utilization of sludge resources. In this paper,discrete shortstaple polypropylene fiber was selected as the reinforced material,cement and fly ash were used as the solidified materials. The unconfined compression test was carried out to study the strength change of the fiber reinforced solidified sludge in the drying path,and the drying was analyzed. The influence mechanism of different target moisture content states(5%~45%)and fiber content(0~0.8%)on the strength of reinforced solidified sludge during the process. The results show that:①The addition of fiber can effectively improve the peak strength and residual strength of solidified sludge,and the strength value increases first and then decreases with the increase of fiber content,and the optimal fiber content is 0.1%.②During the drying process,the sample of the unconfined compressive strength increases with the decrease of the moisture content of approximate to linear, and the damage form by the plastic damage to brittle fracture transition gradually,and the addition of fibers can effectively restrain the brittle failure sample,enhance the toughness of specimen.③The contribution of fiber reinforcement to the strength of solidified sludge increases gradually with the decrease of moisture content,and the root cause is that the fiber-sludge interface force can be better excited under the condition of low moisture content.