In recent decades, sustainable management of construction and demolition waste is an essential aspect of pollution control and solid waste management practices. Since national statistics on construction and demolition waste (C&D Waste) have been collected in 1995, its generation has annually increased in Korea. According to the National Statistics in Korea, about 50% of all waste streams were generated from construction sector in 2013. Recently, intensive studies have been performed to develop sustainable management practices on the waste. Under the guideline on C&D waste treatment, recycling should preferably be employed prior to final disposal (e.g., landfilling). The regulatory obligation and governmental supporting system has raised the awareness of recycling and reuse in construction industry. However, it has frequently been raised an issue of official statistical inaccuracy of C&D waste recycling rate, 97.5%. This is partly due to inadequate data and data handling protocols that cannot often reflect real recycling processes of the waste. Methods based on material flow analysis can be a proper alternative to provide reliable recycling rate of C&D waste.

In this study, the recycling processes of C&D waste were analyzed, and its national recycling rate was estimated using material flow analysis. Available statistical data provided by Ministry of Environment and Korea Environment Corporation were used for material flow analysis. The collected data were validated with field investigations. System boundary of the material flow analysis covered from waste generation step in construction site to final disposal, and the analysis was performed using statistical data for 2013.

The field investigation showed that recycled aggregate is produced through sorting and mechanical shredding of C&D waste. The production efficiency (or process yield) was about 81.2%. The foreign materials in the waste accounted for 18.8% of the weight, and plastic waste materials composed 9.7% of incoming waste. The separated impurities were sent to recycling facilities, combustion plants and landfill sites, according to physico-chemical constitution. Efficiency of recycling facilities and the statistical data were integrated to estimate the national actual recycling rate, which turned out to be 87.7%. Approximately 49.1% of the construction-related waste was recycled as recycled aggregate for concrete production and base material layer for an asphalt pavement. In the future, various types of waste treatment facilities should be investigated as well as aggregate recycling facility to verify the actual recycling rate. Statistical accuracy should be assured through additional field investigations. Our findings can be applicable to development of policies and best management practices for construction and demolition waste as primary data.