Development and validation of a recycling system policy for construction and demolition materials

Abstract

This thesis addresses the lack of proper management of reusable materials known as Construction and Demolition Waste (CDW) in developing countries. Construction and demolition waste refers to concrete, brick, asphalt, gravel, and angular sand. These materials are currently considered as waste and often, more likely always in developing countries, disposed of in dumping sites. This is regardless of the fact that they may be fully or partially reclaimed or recycled in new construction projects, saving valuable, scarce, and non-renewable resources. In addition to the depletion of natural resources, the disposal of construction and demolition waste causes substantial clogging of disposal sites with associated social and severe environmental impacts. It is in this context that this thesis first identifies and characterizes construction and demolition waste in Libya and Tunisia as two sample developing nations, and then develops and validates a basic recycling strategy called the Virgin-Material-for-UsedMaterial. The thesis then proposes avenues to consider for incentivizing the construction sector stakeholders, in developing countries, to use it; and finally, it carries out an environmentally and economically sustainable road intervention using recycled construction and demolition waste. System dynamics simulation is the main methodological approach used considering its versatility to define and analyze complex dynamic systems using computer models that include both qualitative and quantitative variables. Three models were thus created, each addressing a distinct research objective. The first model depicted and analyzed the composition and characteristics of Libya’s annual construction and demolition waste production as a function of mainly cement production, cement consumption, population and its growth, and gross domestic product. The second model establishes an initial model of a recycling framework for construction and demolition waste in a case study of the construction sector in Nalut, Libya. The cost savings and convenience of using the recycling framework tend to motivate stakeholder participation. The third model predicts the future distress of the recycled pavement as a function of the characteristics and composition of the construction and demolition waste and is validated on rehabilitated roads in the Port of Rades in Tunisia. The findings of the research are threefold. Since it is difficult to determine the exact amount of construction and demolition waste, and it is easy to estimate it instead, this study identified appropriate and relevant parameters that adequately describe and examine construction and demolition waste quantities generated on reasonable grounds. Cost savings are, for stakeholders, an effective motivator for recycling construction and demolition waste. Besides, the system dynamics model analyzing Libyan construction and demolition waste management is validated. It is also observed that sustainable road rehabilitation interventions can employ recycled materials successfully without compromising the technical quality of infrastructure, less so the economic cost-effectiveness and the social impact. Overall validation essentially consists of sensitivity analyses and a brief socio-political analysis.

Date	12 Oct 2022
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Gabriel J. Assaf (Supervisor)