Role of superabsorbent polymer in compression behavior of high water content slurries.

Efficient dewatering plays a crucial role in land reclamation projects involving dredged slurry with high water content. Superabsorbent polymers (SAP), renowned for their exceptional water absorption capacity, have emerged as potential environmentally friendly and highly efficient dewatering agents for large-scale slurry dewatering. This study aims to investigate the compressive behavior of SAP-treated high water content slurry soils used in backfilling dredged soils. One-dimensional consolidation tests, starting from a low effective stress of 1.5 kPa, were conducted on mixtures of dredged slurry combined with SAP. The results reveal the significant influence of SAP on the virgin compression behavior of SAP-slurry mixtures, primarily attributed to alterations in soil fabric and the formation of an "apparent soil structure" in SAP-slurry mixtures with high initial water contents. The remolded yield stress σ′yr and the void ratio (eyr) at σ′yr of SAP-slurry mixtures are influenced by two key factors: (1) changes in the initial void ratio (eeq0) and the void ratio at liquid limit (eL), computed by considering the reconstituted soil without SAP, and (2) changes in "apparent soil structure" induced by SAP, quantified by a parameter associated with the swelling potential of SAP. Under effective vertical stress σ′v close to σ′yr, the loss of "apparent soil structure" exhibits two patterns: a sudden loss pattern with minimal deformation for 1–2% SAP and a gradual loss pattern with significant deformation for 3% SAP. Once the "apparent soil structure" disappears, the compression curves for slurries with different SAP contents can be effectively normalized using the intrinsic compression line (ICL) and extent intrinsic compression line (EICL). The intrinsic compression index C*c for SAP-slurry mixture correlates well with the observed variations in reconstituted soil, which considers the variation in eeq0 and eL. However, the SAP content tends to affect the compression parameter e*100, enlarging it for 1% and 2% SAP, while reducing it for 3% SAP. Based on the experimental data, a new empirical equation is proposed to normalize the variation of e*100 with eeq0 and eL for SAP-slurry mixtures. These findings emphasize the substantial improvement in the unfavorable properties of high water content slurry soils through the use of SAP, providing valuable theoretical and practical support for utilizing dredged soils as backfill materials. [ABSTRACT FROM AUTHOR]