HSM, Univ Montpellier, IMT Mines Ales, CNRS, IRD, Ales, France.
LMGC, Univ Montpellier, IMT Mines Ales, CNRS, Ales, France.
Sci Total Environ. 2023 Feb 1;858(Pt 2):159980. doi: 10.1016/j.scitotenv.2022.159980. Epub 2022 Nov 5.
The integrated life cycle assessment (LCA), life cycle cost assessment (LCC) and laboratory-based experimental assessment were applied to provide insight for early stage decision-making on the valorization of the dredged sediments. The objective was to find a viable and sustainable solution for the valorization of the dredged sediment in concrete, holding up a certain level of standard concrete performance without compromising in terms of economy and environment. For the sensitivity analysis, parametric life cycle inventories were developed to assess the sensitivity of environmental and economic costs to the rate of sand substitution by sediment, as well as the variations in the concrete components. The workability of fresh concrete and the compressive strength of hardened concrete at 28 days were assigned as the quality indicators to evaluate the influence of sand substitution by sediment on the concrete performance. The compressive strength evaluation in the laboratory demonstrated that a maximum rate of sand substitution in concrete up to 40 % by predominantly sandy sediment could sustain the concrete strength class. However, LCA and LCC negated the rate of sand substitution by sediment higher than 20 %. The integrated environmental, economic, and experimental assessments demonstrated that the substitution of sand by predominantly fine sediment downgrades the strength class of concrete, even in the low rate of incorporation (10 %) and increases the environmental and economic costs. Inferred from the results, the maximum rate of sustainable sand substitution by sediment in concrete could be optimized through a compromise between the expected mechanical strength and workability of the concrete, the economic and environmental impacts of the superplasticiser and the sediment transport. Overall, integrating environmental and economic cost assessments into the laboratory-based assessment of the valorization scenarios would determine the threshold for the sustainable rate of incorporation of sediment in valorization scenarios.
综合生命周期评估（LCA）、生命周期成本评估（LCC）和基于实验室的实验评估被应用于为疏浚沉积物的增值早期决策提供深入了解。目标是为疏浚沉积物在混凝土中的增值找到可行和可持续的解决方案，在不影响经济和环境的情况下保持一定水平的标准混凝土性能。为了进行敏感性分析，开发了参数化生命周期清单，以评估环境和经济成本对沉积物替代砂率的敏感性，以及混凝土成分的变化。新鲜混凝土的工作性和 28 天硬化混凝土的抗压强度被指定为质量指标，以评估沉积物替代砂对混凝土性能的影响。实验室的抗压强度评估表明，在混凝土中，主要由砂质沉积物替代砂的最大替代率可维持混凝土强度等级。然而，LCA 和 LCC 否定了高于 20%的沉积物替代砂率。综合环境、经济和实验评估表明，主要由细沉积物替代砂会降低混凝土的强度等级，即使在低掺入率（10%）下，也会增加环境和经济成本。从结果推断，通过在预期混凝土的机械强度和工作性、超塑化剂和沉积物运输的经济和环境影响之间进行折衷，可以优化混凝土中沉积物可持续替代砂的最大比率。总的来说，将环境和经济成本评估纳入增值方案的基于实验室的评估中，可以确定在增值方案中可持续掺入沉积物的比率的阈值。
