Reducing Embodied Carbon Emissions of High-rise Concrete Modular Buildings Leveraging Lightweight Module Design

To reduce embodied carbon (EC) emissions from the construction industry, promoting modular buildings, especially for highly populated regions, is of crucial importance. Nonetheless, the heavyweights of concrete modules have been reported to lead to a series of logistical problems in manufacturing, transportation, and hoisting. On the other hand, the double-panel issues in modular buildings posed concerns related to inefficient material usage, thus leading to potential EC increments. This paper aims to adopt the practical and idealized parametric lightweight designs of modules to estimate the EC reductions throughout the cradle-to-end-of-construction stages. Two types of lightweight module designs, i.e., dematerialized module and lightweight concrete module, were examined in high-rise concrete modular buildings in Hong Kong, considering the structural system features. The results indicate that the utilization of lightweight concrete in non-structural components of modular buildings resulted in EC reductions of 10.1% for a typical floor. Dematerialization by 30% on modules exerts the potential to reduce 11.6% EC for modular buildings compared to regular designs. The findings presented in this paper could provide valuable reference to assess the carbon-saving potentials of adopting lightweight modules in Hong Kong and worldwide.