Abstract

Superabsorbent polymers (SAPs) absorb more water than their mass. When applied to frigid, semiarid soils, they may modify physical processes and amplify winter freezing-thawing effects for remediating compaction. If so, SAPs may be an effective amendment in reclamation projects. Laboratory tests evaluated SAPs influences on setting antecedent soil moisture and mechanical conditions prior to freezing-thawing. This was done by evaluating evaporation characteristics, water retention, and Atterberg limits on five soil series of differing textures as affected by SAP application rates (0, 40, 80, and 200 mg SAP kg⁻¹dry soil). Then, soil columns with and without freeze-thaw cycles were evaluated for each SAP rate to determine if SAP amplified freezing-thawing to remediate compaction. This was done by observing changes in soil bulk density, peak penetration resistance, and saturated hydraulic conductivity (Ksat) as indicators of compaction. Results demonstrated that increasing SAP rates significantly decreased evaporative water losses, increased water retention, and increased the liquid limit. In a field setting, these trends would set antecedent soil conditions that favor the remediation of compaction during subsequent winter freeze-thaw cycles. Results also demonstrated that SAP significantly affected the freezing-thawing process on some indicators of soil compaction. Increases in SAP rates significantly decreased peak penetration resistance, had mixed effects on Ksat, but no effect on bulk density. This suggests particle rearrangement is occurring internally (i.e., aggregation) even though changes in bulk density are not evident. Application of SAP appears to have potential for amplifying the remediation of soil compaction during winter in frigid, semiarid environments.

摘要

高吸水性聚合物 (SAP) 吸收的水比其质量多。当应用于寒冷、半干旱的土壤时，它们可能会改变物理过程并放大冬季冻融效应以修复压实。如果是这样，SAPs 可能是填海项目的有效修正。实验室测试评估了 SAP 对冻融前设定的前期土壤水分和机械条件的影响。这是通过评估受 SAP 施用率（0、40、80 和 200 毫克 SAP kg ^-1干土）。然后，针对每个 SAP 速率评估具有和不具有冻融循环的土柱，以确定 SAP 是否放大了冻融以修复压实。这是通过观察土壤容重、峰值渗透阻力和饱和导水率 (Ksat) 作为压实指标的变化来完成的。结果表明，提高 SAP 速率显着降低了蒸发失水，增加了保水率，并提高了液限。在田间环境中，这些趋势将设定有利于在随后的冬季冻融循环中修复压实的先行土壤条件。结果还表明，SAP 显着影响了土壤压实的某些指标的冻融过程。SAP 速率的增加显着降低了峰值渗透阻力，对 Ksat 有混合影响，但对体积密度没有影响。这表明颗粒重排在内部发生（即聚集），即使堆积密度的变化不明显。SAP 的应用似乎有可能在寒冷、半干旱的环境中加强冬季土壤压实的修复。