Department of Structural Eng., College of Civil Eng., Tongji University, Shanghai 200092, PR China.
Department of Structural Eng., College of Civil Eng., Tongji University, Shanghai 200092, PR China; Key Laboratory of Performance Evolution and Control for Engineering Structures, Tongji University, Ministry of Education, Shanghai 200092, PR China.
Waste Manag. 2020 Mar 15;105:268-278. doi: 10.1016/j.wasman.2020.02.015. Epub 2020 Feb 20.
In the construction industry, reuse and recycling strategies help reducing waste, saving energy and cutting down emissions by converting construction and demolition (C&D) waste into resources. This study proposes a novel framework to guide the life cycle assessment (LCA) of concrete structures with reuse and recycling strategies. The material flow in recycling strategies is clarified explicitly. A new definition of degradation rate is introduced to set a nonlinear allocation rule for reusable components based on the durability feature of concrete structures. Reusable rate and replacement percentage are adopted to provide a convenient way to adjust the type and level of the strategies. As a result, a unified system boundary and corresponding indicator functions can be established for various strategies, combing the closed-loop analysis and the open-loop analysis. In the case study, design for deconstruction (DfD) and recycled aggregate concrete (RAC) are taken as examples of reuse and recycling strategies, respectively. With the proposed framework, LCA of various strategy combinations are conducted considering the global warming potential (GWP) and abiotic depletion potential (ADP) indicators. Results show that the maximal environmental benefit of DfD is 1.8-2.8 times compared to that of RAC. When adopting DfD and RAC simultaneously, the environmental benefit level of each strategy will decline, whereas the overall benefits will be increased. LCA with the proposed framework avoids some assumptions in conventional LCA and provides more reliable results for various strategy combinations.
在建筑行业，再利用和回收策略通过将建筑和拆除（C&D）废物转化为资源，有助于减少浪费、节约能源和减少排放。本研究提出了一种新的框架，以指导具有再利用和回收策略的混凝土结构的生命周期评估（LCA）。明确了回收策略中的物质流。引入了新的降解率定义，根据混凝土结构的耐久性特征，为可重复使用的组件设置非线性分配规则。采用可重复使用率和替换百分比，为调整策略的类型和水平提供了一种便捷的方法。结果，可以为各种策略建立统一的系统边界和相应的指标函数，将闭环分析和开环分析结合起来。在案例研究中，分别将拆卸设计（DfD）和再生骨料混凝土（RAC）作为再利用和回收策略的示例。使用所提出的框架，考虑全球变暖潜力（GWP）和非生物消耗潜力（ADP）指标，对各种策略组合进行了 LCA。结果表明，与 RAC 相比，DfD 的最大环境效益是其 1.8-2.8 倍。同时采用 DfD 和 RAC 时，每种策略的环境效益水平会下降，但整体效益会增加。该框架下的 LCA 避免了传统 LCA 中的一些假设，为各种策略组合提供了更可靠的结果。
