Unveiling Construction and Demolition Waste Dynamics: A Case Study of the Building Construction Sector in Sri Lanka

Construction and demolition waste (CDW) generation is an increasing global concern. Despite the significance of the construction industry to the economy of Sri Lanka, limited studies have been conducted on this topic, and no proper guidelines have been developed. Therefore, a comprehensive study on CDW is necessary to establish the required framework for developing guidelines for effective CDW management. This study aims to address this gap by investigating CDW generation in the building construction sector in Sri Lanka. The study examines the generation patterns and current management strategies of CDW in different phases at different conditions of significant construction projects in Sri Lanka. To ensure a representative sample, construction sites in the Colombo and Kandy districts were carefully selected, representing various project types and stakeholders, including public and private owners, commercial establishments, residential projects, and office structures. Data was collected by a rigorous questionnaire survey of stakeholders from 32 construction and demolition projects, complemented by face-to-face interviews with responsible higher officials. Key findings include high average wastage percentages for asbestos (7.4%) and ceramic tiles (7.1%), varying concrete wastage rates across building types (8.2% in high-rise structures, 5.2% in low-rise buildings, and 4.0% in medium-rise buildings), and potential inefficiencies in material use procedures. Substructure components show room for improvement in material consumption, with a wastage percentage of 6.3%, while superstructure components demonstrate relatively efficient material management, with a wastage ratio of 4.8%. Analysis of demolition waste composition reveals significant proportions of brick (25%), concrete (20%), timber (8%), and steel (6%), highlighting the importance of proper handling and disposal practices. Overall, finding of this study show that comprehensive waste management strategies are required, and the types of waste generated during building construction vary depending on factors such as construction stage, building size, contractor grade, etc.