Abstract

The safe treatment of marine sediment has been a global-scale challenge. To reduce the environmental impacts associated with Portland cement (PC), an environment-friendly binder consisting of quicklime and ground granulated blast-furnace slag (GGBS) was used in the stabilization/solidification of natural marine sediment. Although the combination of lime and GGBS is used to stabilize the sediment with very low water content or moderate water content in previous studies, the natural marine sediment with such a high water content has not been treated by the quicklime–GGBS binder up to now. Therefore, a series of tests were performed to study the physicochemical, mechanical, and microstructural characteristics of quicklime–GGBS stabilized sediments. The results indicated that the quicklime–GGBS solidified/stabilized sediment had a similarly low water content at a proper quicklime-binder ratio to that of PC-stabilized sediments. The pH of quicklime–GGBS solidified sediments gradually decreased as the quicklime-binder ratio decreased and the curing period increased. The unconfined compressive strength (UCS) of quicklime–GGBS stabilized sediments was 1.4 times higher than that of the corresponding PC-stabilized sediments using the same test conditions. The hydration products effectively bonded the sediment particles and filled the pores between the sediment particles, facilitating the improvement of the UCS of the quicklime–GGBS stabilized sediment. The findings indicated that the use of GGBS and a small amount of quicklime can replace PC to stabilize natural marine sediment with high water content. This would be to provide binder dosage and component proportion for the field application of quicklime–GGBS binder and to significantly improve the economical and environmental effects of the treatment of high water content sediment.

• HIGHLIGHTS

• Innovative lime-activated GGBS is used as a binder in the improvement of sediment with ultrahigh water content.

• The water content, pH, and UCS of lime–GGBS stabilized sediments are contrastively studied.

• The engineering performances of lime-GGBS stabilized sediments are better than those of PC-stabilized sediment.

• An optimal and appropriate lime-binder ratio is suggested.

• Microstructure mechanism of lime–GGBS stabilized sediment is revealed through series of micro-tests.

摘要

海洋沉积物的安全处理一直是全球范围内的挑战。为了减少波特兰水泥（PC）对环境的影响，由生石灰和磨碎的粒化高炉矿渣（GGBS）组成的环保粘合剂被用于稳定/固化天然海洋沉积物。尽管在以往的研究中使用石灰和GGBS的组合来稳定含水量极低或中等含水量的沉积物，但迄今为止，尚未使用生石灰-GGBS粘合剂处理如此高含水量的天然海洋沉积物。因此，进行了一系列测试来研究生石灰-GGBS稳定沉积物的物理化学、力学和微观结构特征。结果表明，在适当的生石灰-粘合剂比例下，生石灰-GGBS固化/稳定沉积物的含水量与PC稳定沉积物相似。生石灰-GGBS固化沉积物的pH随着生石灰与粘结剂比例的降低和固化时间的延长而逐渐降低。在相同的测试条件下，生石灰-GGBS稳定沉积物的无侧限抗压强度（UCS）比相应的PC稳定沉积物高1.4倍。水化产物有效地粘合沉积物颗粒并填充沉积物颗粒之间的孔隙，有利于生石灰-GGBS稳定沉积物UCS的提高。研究结果表明，使用GGBS和少量生石灰可以代替PC来稳定高含水量的天然海洋沉积物。为生石灰-GGBS粘结剂的现场应用提供粘结剂用量和组份配比，显着提高高含水底泥处理的经济和环境效果。

• 强调

• 创新的石灰活化 GGBS 作为粘合剂用于改善超高含水量的沉积物。

• 对比研究了石灰-GGBS稳定沉积物的含水量、pH值和UCS。

• 石灰-GGBS稳定沉积物的工程性能优于PC稳定沉积物。

• 建议采用最佳且合适的石灰-粘合剂比例。

• 通过一系列微观试验揭示了石灰-GGBS稳定沉积物的微观结构机制。