Long-term strength and deformation tendencies of a mesocosm-cured cement-stabilized fine-grained sediments

Abstract Purpose This experimental program aimed to systematically evaluate the long-term evolution of the engineering performance of a stabilized sediment. Specifically, this program aimed to understand how the strength and deformation tendencies of the sediment evolved beyond standard 28-day metrics which are typically utilized. Materials and methods An organic fine-grained sediment was stabilized with 4% Portland cement by wet weight and monitored and evaluated over 12 months of curing in small mesocosms that were designed to better mimic field conditions. High quality samples were regularly obtained using Shelby tubes. The sediments engineering performance (strength and deformation tendencies) was evaluated using a combination of unconfined compressive strength, oedometer, and direct simple shear testing as well as a suite of index property tests. Mesocosm cured specimens were compared with samples created following traditional laboratory techniques and cured under the same conditions. Results and Discussion Stabilized sediment behavior was shown to continue to evolve (generally improve) over the 12 months of monitoring, suggesting that the current 28-day approaches used in practice may be conservative. The sediment was found to have relatively high undrained strength ratios, high apparent preconsolidation pressures, and did not show the potential for post-peak strength loss; which suggests stabilized sediment could be used in infrastructure construction applications. Conclusions Results of the experimental program showed the strength and deformation tendencies of the stabilized sediment may have the potential for use in structural applications with greater strength or deformation requirements, providing a potential new use for fine-grained materials in practice.