Sustainability implications of using precast concrete in construction: An in-depth project-level analysis spanning two decades

Conventional cast in-situ, precast and prefabricated construction are construction methodologies with increasing construction modularity. Construction methodologies and modularity, in turn, are determinants of sustainability onsite. This paper analyses 38 construction projects in Hong Kong, spanning a substantial period of twenty years for a systematic comparison on their construction methodology and sustainability performance. Specific indicators are developed to evaluate projects’ sustainability performance with various levels of prefabrication. Environmental sustainability indices capture the carbon emission and waste generation of projects. Social sustainability indices represent the human resource usage and overall accident rate of projects. Economic sustainability indices denote the project cost and time used for completion. Finally, a composite sustainability index is compiled. The study finds significant positive correlations between the percentage of prefabrication applied onsite and the sustainability attributes. Detailed project analysis further suggests that the highest sustainability performance was found in projects that adopted modular construction methodology (MiC) as the primary construction methodology. • Construction methodologies, level of modularity and sustainability are interrelated. • Hong Kong's building construction has been increasingly modularized since the 1990s. • Construction-specific Composite Sustainability Index (CSI) used to evaluate sustainability onsite. • Level of prefabrication and construction sustainability are positively correlated. • Project adopted highest level of prefabrication (88%) achieved the highest CSI (84.4).