Combining life cycle assessment and Building Information Modelling to account for carbon emission of building demolition waste: a case study

Abstract

Building demolition waste presents a significant challenge due to its large scale. Especially, the treatment of waste (i.e. demolition, collection, sorting, transportation, recycling and landfill) has environmental implications, e.g. carbon emissions due to energy consumed by equipment and vehicles. Therefore, it is imperative to identify the appropriate waste treatment methods with low carbon emissions. However, previous studies predominately focused on quantifying the carbon emission of buildings. In contrast, the carbon emission derived from the treatment of building demolition waste is largely overlooked. A conceptual framework is developed in this study to facilitate the assessment of carbon emissions over the life cycle of building demolition waste. In this conceptual framework, Building Information Modelling provides an effective approach to harvest data and feed into the Life Cycle Assessment. Case study of a high-rise residential building was conducted to showcase how this framework can be implemented in practice. Results showed that the environmental benefit derived from recycling of building demolition waste varies from one material to another. The recycling of metal waste has far higher environmental benefits compared to masonry wastes. In particular, aluminum could contribute to as high as 45% of carbon emission reduction despite only accounting for 0.66% of the total weight. Across various lifecycle stages, the onsite collection and sorting is the biggest contributor to the total carbon emission. In addition, on-site recycling has better performance compared to factory recycling and landfill in terms of carbon emissions. Furthermore, a large scale inventories are developed as an outcome of this case study. These findings provide useful inputs to the future endeavor of building demolition waste recycling in a bid to reduce the associated carbon emissions.