The construction industry is a major contributor to global carbon emissions, with embodied carbon in building materials representing a significant portion of this impact [1]. To mitigate these emissions, there is a pressing need to develop low-carbon structural designs [2]. This research focuses on comparing the embodied carbon associated with reinforced concrete (RC) beams designed according to two prominent building codes: ACI-318 [3] and Eurocode 2 [4].
This research hypothesizes that the choice of design code significantly influences the embodied carbon emissions of reinforced concrete (RC) beams. Specifically, it is proposed that adopting the ACI-318 code over Eurocode 2 (EC2) can lead to substantial reductions in embodied carbon by optimizing steel reinforcement and minimizing concrete sections.
By analyzing the design methodologies prescribed by these codes, this study aims to identify key differences and similarities that impact the embodied carbon footprint of RC beams. Through the derivation of equations from the codes, the research correlates structural design parameters (concrete strength, beam dimensions, reinforcement ratio, and load conditions) with the resulting embodied carbon emissions.
A total of 100 RC beams were designed using both ACI-318-19 and Eurocode 2, covering a wide range of practical design scenarios. Embodied carbon emissions were calculated for both concrete and steel components, considering production, transportation, and construction stages.
The results demonstrate that RC beams designed using ACI-318 generally exhibit lower embodied carbon emissions compared to those designed according to Eurocode 2. This is attributed to the ACI code's more direct approach to determining section dimensions based on reinforcement ratio and b/d ratio, often leading to more economical designs. On average, a carbon reduction of 25% was achieved through the ACI code, with variations ranging from 16% to 40% depending on specific design parameters.
This research contributes to the understanding of how design code choices impact the embodied carbon of RC structures. The findings highlight the potential for significant carbon reductions through the adoption of optimized design methods like those presented in the ACI code. Further research is recommended to explore the applicability of these findings to other structural elements and to incorporate life-cycle assessment for a more comprehensive evaluation of environmental impacts. By providing a quantitative comparison of embodied carbon emissions, this study offers valuable insights for structural engineers seeking to reduce the environmental footprint of their designs.