Optimization of RC Structures with Regard to Amount of Embodied CO2 Emissions

Abstract

The volume of CO2 emissions (and other greenhouse gases) has been rising almost continuously for several decades. Concrete is the most used man-made material in the world, thus the construction of reinforced concrete (RC) structures is associated with high environmental impact, mainly due to the consumption of cement as binder for concrete and steel as reinforcement. This article analyses the available options for the design of RC structure to reduce embodied CO2 emissions. The main part of the article is a case study demonstrating optimization of the load-bearing structure of multi-storey building. Emphasis was placed on achieving the optimal variant in terms of CO2 emissions, while maintaining a comparable cost of the construction. The results of this study show that in this particular case the use of concrete with a lower strength brings lower environmental impact than of concrete with higher strength. The reason is that the production of lower strength concrete allows the use of cements with a lower clinker content which is decisive for CO2 emissions. However, the use of concrete with higher strength allows more subtle structural members with lower content of concrete and potentially with higher durability.