Estimating the Generation of Construction and Demolition Waste by Using System Dynamics: a Proposed Model

During the past decades, construction and demolition (C& D) waste has received increasing attention from construction practitioners and researchers around the world. A plethora of research has been published in various academic journals. These studies have investigated a wide range of topics under the umbrella of C& D waste management, of which investigation into the generation of C& D waste in various economies is an obvious component, as estimating the generation of future C& D waste is of major importance for decision making and planning. However, a question that arises here is: How can we forecast the development of a dynamic and complex waste management system? Up-to-date research shows that previous studies regarding C& D waste have been mainly separately concentrating their work on measuring C& D waste through various methods, including direct observation, comparing contractors ' records, sorting and weighting the waste materials on site, consultation with construction company employees, and truck load records, but without incorporating the inter-related factors involved in the waste management process. By acknowledging their contributions to providing information for understanding different C& D waste management practices, there is apparently a general lack of approaches that enables us to holistically consider the inter-relations and interdependences of factors within the C& D waste management process. Bearing this in mind, this research proposes a model that is based on system dynamics approach to serve as a decision support tool for estimating the C& D waste generation. The dynamic model integrates all vital factors that affect and are affected by C& D waste generation. The software ' iThink ' is used to help with the depiction of the model. The aim of the research presented here is twofold: first, to incorporate the nature of dynamics into the modeling process which are not easily measureable, but are vital to descriptions of C& D waste management. Second, based on the proposed model, C& D waste management strategies could be analyzed under different scenarios, thus the best strategies can be identified for long-range planning.