基于低场核磁共振技术解析碱激发矿渣固化淤泥的水分演化及孔结构OA

Excessive free water in dredged sediment(DS)has a negative impact on the strength,durability and volume stability of the solidification system.This paper investigated the effects of water content of DS and ratio of curing agent to DS on hydration and pore structure of DS solidified with alkali-activated slag(AAS)based on low-field nuclear magnetic resonance technology.A novel method for quantitatively characterizing water hydration and transport was proposed,thereby deepening the understanding of the mechanism of water action during the solidification process.The results show that small-sized pores could effectively trap moisture through capillary force.When the water content of DS increases from 50%to 80%,the proportion of capillary pores increases,and the connectivity of the matrix pore network is enhanced.It results in an enhanced water transport effect,and part of water in capillary pores migrates directionally to the large pores about 160 nm due to humidity differences,and participates in secondary hydration reactions with unreacted slag.Increasing the ratio of curing agent to DS allows more water to participate in the hydration reaction.This not only refines the pore structure,but also weakens the water transport effect.The increase of hydration products improves the mechanical properties,and mitigates the adverse impact of high water content on the comprehensive perfor-mance of the system.